Patent Application
20050099628
1. Field of the Invention
The present invention relates: to a mark for position detection, which is provided upon an object, and which is used when detecting positional information of this object; to a mark identification method and a mark detection method for identifying a specific mark from a plurality of marks; to an exposure method, in which a pattern upon a substrate is exposed to light; and to a positional information detection method.
2. Description of Related Art
A micro device such as a semiconductor element or a liquid crystal display element or the like is manufactured by repeating each of a film manufacture processing process, a processing for exposure to light process, and an etching processing process and the like a plurality of times, thus layering a plurality of patterns upon a substrate. In this processing for exposure to light, an exposure device is utilized for transcribing a pattern which is formed upon the mask to a substrate upon which a photosensitive material is applied. This exposure device comprises a mask stage which supports the mask and shifts it in two dimensions, and a substrate stage which supports the photosensitive substrate and shifts it in two dimensions; and the pattern upon the mask is transcribed to the photosensitive substrate while sequentially shifting the mask stage and the substrate stage. Since, in the processing for exposure to light, it is necessary to superimpose the image of the pattern which must be next superimposed upon the pattern which is already formed upon the substrate with good accuracy, accordingly alignment is performed between the shot region upon the substrate and the mask which has the pattern for the subsequent layer.
Normally, in the alignment procedure for the substrate, there are performed: a pre-alignment procedure, which is a preliminary positional alignment when the substrate is loaded upon the substrate stage; a search alignment procedure in which, in the state with the substrate supported upon the substrate stage, a rough positional alignment is performed by using two or three search marks which are provided upon the substrate; and a fine alignment procedure in which, using the result of the search alignment procedure, the substrate is finely positionally aligned. Among these, in the fine adjustment procedure, a deviation and a rotation and the like of the substrate in the two dimensional directions (the plane direction, the XY direction) with respect to a standard position are obtained from the result of the search alignment, and, based upon these, the position of the design upon each shot region (alignment mark), and the position (the measured value or the calculated value) which was used for the pattern transcription for the previous layer are compensated, the alignment marks are guided within the measurement region of the alignment optical system by using these compensated positions, and, the fine alignment of the substrate is performed by detecting these.
Here, as a method of fine alignment, apart from the die by die alignment method in which an alignment mark is detected in each of the shot regions upon the substrate, and alignment is performed with the pattern which is transcribed upon the substrate, there is an EGA (Enhanced Global Alignment) method. With this EGA method, the positions of alignment marks are detected which are respectively associated with at least 3 shot regions which are selected from a plurality of shot regions upon the substrate (these are termed the sample shot regions), and the position of each shot region upon the substrate is calculated statistically by an approximation calculation procedure, using the actual positions of the alignment shot regions and their design positions (or their compensated positions). By doing this, the substrate is shifted in order according to these positions which are calculated, and the respective patterns upon the mask for each of the subsequent layers are transcribed onto the plurality of shot regions in the state of being accurately positionally aligned. It should be understood that the measurement region of the alignment optical system is set as the center of the design position of the search mark during the search alignment procedure, and is set as the center of the design position or of the compensated position of the alignment mark during the fine alignment procedure. The alignment optical system detects the mark within the measurement region.
Although in, for example, the manufacture of a semiconductor device it may happen that the alignment marks are transcribed onto each layer as shifted, in this case, when an alignment mark which has been used for the previous layer (or for the previous to the previous layer) is visible through the layer above, then it may happen that a mark of the same type (a mark upon the previous layer) comes to be present in the vicinity of the alignment mark which is the subject of detection. When the alignment marks are present in the vicinity of one another, even if the system has guided the alignment mark which is the subject of detection in the measurement region of the alignment optical system based upon the accuracy of the pre-alignment, it may happen that a plurality of marks of the same kind undesirably enter into the measurement region, or that only a mark other than the subject of detection enters into the measurement region. In this case since, with a prior art alignment optical system, during the fine alignment, it is not decided whether any mark is the subject for detection, or whether a mark within the measurement region is the subject of detection, accordingly it may happen (undesirably) that the measurement of the position of an alignment shot region is performed based upon an erroneous alignment mark which is not the subject of detection, which will remarkably deteriorate the accuracy of alignment.
Furthermore, it also may happen that the alignment procedure is performed for a pattern of a subsequent layer by utilizing an alignment mark which was used for the previous layer (or the previous to the previous layer). In this case as well, it becomes difficult to specify the alignment mark for aligning the pattern from the subsequent layer from the large number of alignment marks which include the alignment marks for the previous layer (or the previous to the previous layer).
Yet further, with a sequence in which the search alignment is performed as in the prior art, it is necessary to prevent errors in detection of the search mark during the search alignment. In order for this, a forbidden zone is provided upon the substrate in order to prohibit formation of the same type of pattern (one resembling the search mark) at the vicinity of the search mark. This forbidden zone is provided in order to avoid the erroneous detection of a search mark, by ensuring that no other patterns enter into the measurement region when the search mark has been guided into the measurement region of the alignment optical system. However, the pattern transcription region upon the substrate is reduced in size by just the area of the forbidden zone, and the presence of a forbidden zone is not desirable from the point of view of efficient utilization of the substrate, because it imposes a restriction upon the ease of arrangement of the circuitry, and the like.
Furthermore, with a search mark upon a substrate, since the search mark which is provided upon the mask is transcribed onto the substrate and formed thereupon, each one of the search marks comes to be formed in each of the shot regions upon the substrate. However, since the number of search marks upon the substrate which are utilized in the search alignment procedure is 2 or 3, accordingly a large number of unused search marks which are not used in the search alignment procedure come to be formed upon the substrate. Since the mere existence of these search marks reduces the size of the pattern transcription region upon the substrate, this is not desirable from the point of view of efficient utilization of the substrate.
Even further, in the search alignment procedure, although two or more search marks which are separated upon the substrate are detected by the alignment optical system, when, after the alignment optical system detects the first search mark, it goes to detect the second search mark within the measurement region of the alignment optical system, if for example the substrate is deformed, since the actual relative position of the first search mark and the second search mark is different from the design relative position, the procedure of arranging the second search mark within the measurement region of the alignment optical system does not proceed smoothly.
Furthermore, although the image of the alignment mark which has been detected by the alignment optical system is image processed in the alignment procedure, the speed of processing is higher if the detection of the mark position is performed after compression processing of the image of the mark which has been obtained is performed, than if no such compression processing is performed. However, when compression processing is performed, if the mark is small, it may happen that it becomes impossible to perform detection of the position of the mark because the mark image is, undesirably, spoilt.
Still furthermore, when manufacturing a micro device, although a CMP (Chemical Mechanical Polishing) procedure may be performed in order to flatten the surface of the device, it sometimes happens that, due to the concave and convex state of the surface of the device, the surface of the device contacts the polishing surface of the CMP device at a certain inclination, which is undesirable, so that it may happen that the state of the polishing becomes uneven.
The present invention has been made in consideration of this type of circumstance, and it takes as its objective to provide a mark for position detection and a mark identification method, which, even when a large number of the same type of marks are present in the vicinity of a mark which is to be the subject of detection, can reliably detect this mark which is the subject of detection. Furthermore, it takes as its objective to provide an exposure method, which, by reliably detecting a mark which is the subject of detection, can enhance throughput by maintaining alignment accuracy even during a sequence in which fine alignment is performed, without performing any search alignment after pre-alignment, and which can perform-processing for exposure to light with good accuracy.
In order to solve the above described problems, with the present invention, there are employed the structures below, which correspond to
The mark (10) for position detection of the present invention is provided upon an object (P), and is used when detecting positional information of the object with a position detection device (9, CONT), and it comprises a first pattern (1) for outputting the positional information to the position detection device (9, CONT) by being observed by the position detection device (9, CONT); and a second pattern (2) which is arranged in a predetermined positional relationship with respect to the first pattern (1), and which consists of n patterns (where n=1) of N types (where N=2) combined, thus expressing Nn types of information.
The mark identification method of the present invention is a mark identification method for detecting positional information of an object (P) using a detection device (9, CONT), and for identifying a specific first mark (1A) from a plurality of first marks (1A through 1E) which are provided upon the object (P), and, upon the object (P), along with the first marks (1A through 1E), there is provided a second pattern (2) which is arranged in a predetermined positional relationship with respect to the first marks (1A through 1E), which consists of a combination of n patterns (where n=1) of N types (where N=2), and which expresses Nn types of information; and the second pattern (2) is detected by the detection device (9, CONT), and the specific first mark (1A) is determined based upon information which is expressed by the second pattern (2).
In the position detection method of the present invention, by detecting a specific first mark (1A) which has been determined by a mark identification method as described above using the detection device (9, CONT), it detects the positional information for the object (P).
According to the present invention, by providing the second pattern which is associated in a predetermined positional relationship with respect to the first pattern for outputting positional information, by detecting the state of this second pattern, even if a mark of the same type is present in the vicinity of the mark which is to become the subject of detection, it is possible to specify the mark for use for position detection from this plurality of marks. Furthermore, since the second pattern is made up as a combination of n patterns of N types, even without setting the region for arrangement of the marks upon the substrate to be wide, it is possible to display information of the large number of Nn types. The result of this is that, even though a large number of the same type of mark are present, it is possible to perform mark identification without squeezing down the pattern transcription region upon the substrate.
In the exposure method of the present invention is an exposure method which transcribes a prescribed pattern onto a substrate (P), upon the substrate (P), there are provided a first pattern (1) for detection of positional information by a position detection device (9, CONT), and: a second pattern (2) which is arranged in a predetermined positional relationship with respect to the first pattern (1), and which consists of n patterns (where n=1) of N types (where N=2) combined, thus expressing Nn types of information; the second pattern (2) is detected by the detection device (9, CONT), and, based upon the information expressed by the second pattern (2), the positional information is detected from the first pattern (1); and, based upon the positional information which has been detected, the substrate (P) and the prescribed pattern are shifted relatively to one another, and the prescribed pattern is transcribed onto the substrate (P).
According to the present invention, since the second pattern is provided which is associated in the predetermined positional relationship with respect to the first pattern for outputting the positional information, by detecting the state of this second pattern, even if a plurality of patterns of the same type are present in the vicinity of the pattern which is to become the subject of detection, it is possible to specify the first pattern for use for position detection from this plurality of patterns, based upon the information expressed by the second pattern. Accordingly, it is possible to perform the alignment procedure with good accuracy using this first pattern, and it is possible to enhance the accuracy of the exposure to light. Furthermore, since the second pattern is made up as a combination of n patterns of N types, even without setting the region upon the substrate for arrangement of the first pattern for detecting the positional information to be wide, it is possible to display information of the large number of Nn types. Accordingly, even though a pattern of the same type is present, along with being able to specify the first pattern for use for position detection, it is possible to perform the processing for exposure to light with good accuracy, without squeezing down the prescribed pattern transcription region upon the substrate.
The exposure method of the present invention is an exposure method which transcribes a prescribed pattern onto a substrate (P) in which, upon the substrate (P), there are provided a first pattern (1) and a second pattern (2) which is in a predetermined positional relationship with respect to the first pattern (1), and, among a plurality of marks (1, 10) formed upon the substrate (P): relative positional information for the first pattern (1) and the second pattern (2) of specified marks (1, 10) is detected; based upon the relative positional information, positional information for another mark (1′), among the plurality of marks (1) formed upon the substrate (P), which is different from the specified mark (1) is determined; and, based upon the positional information which has been determined, the substrate (P) and the prescribed pattern are shifted relatively to one another, and the prescribed pattern is transcribed onto the substrate (P).
According to the present invention, by detecting the relative positional information of the first pattern and the second pattern of the specified mark, it is possible, for example, to obtain information related to the amount of deformation of the substrate, or to its amount of rotation. And, even in a case such as when the relative position of the specified mark and another mark is different from their design relative position, it is possible to determine the positional information of the specified mark and of the other mark based upon the information which has been obtained. Accordingly, when detecting the other mark after having detected the specific mark within the measurement region of the position detection device, it is possible to perform shifting of the substrate smoothly, since the other mark is arranged in the measurement region of the position detection device.
The mark detection method of the present invention is a mark detection method which, using a mark detection device (9, CONT) of an image processing method which has a predetermined measurement region, detects a second mark (2) from upon an object (P) upon which are formed a first mark (1) and the second mark (2) which is in a predetermined positional relationship with respect to the first mark (1) and which is smaller than the first mark (1), and an image of the measurement region is photographed and image data is acquired; the image data is subjected to compression processing; positional information for the first mark (1) is detected from the image data which has been compression processed; and, based upon the positional information for the first mark (1) which has been detected, and relative positional information for the first mark (1) and the second mark (2), positional information for the second mark (2) is detected from the image data for the measurement region which have been photographed.
The exposure method of the present invention is an exposure method in which, using a mark detection device (9, CONT) of an image processing method which has a predetermined measurement region, a second mark (2) is detected from upon a substrate (P) upon which are formed a first mark (1) and the second mark (2) which is in a predetermined positional relationship with respect to the first mark (1) and which is smaller than the first mark (1), and, after having performed positional alignment of the mask (M) and the substrate (P), a pattern upon the mask (M) is exposed to light onto the substrate (P) such that an image of the measurement region is photographed and image data is acquired; the image data is subjected to compression processing; positional information for the first mark (1) is detected from the image data which has been compression processed; and, based upon the positional information for the first mark (1) which has been detected, and relative positional information for the first mark (1) and the second mark (2), positional information for the second mark (2) is detected from the image data for the measurement region which have been photographed.
According to the present invention, if for example the mark detection device is a detection device of an image processing method, then, although sometimes it happens that it is possible to enhance the processing speed by performing the mark detection after the image data has been compressed, it also sometimes happens that an inconvenience occurs, such as that the image of the second mark is blurred by the compression procedure, which is undesirable. However, by providing the first mark which is in a predetermined positional relationship with this second mark and moreover is larger than the second mark, the image data of this first mark is not blurred, even if compression processing is performed. Accordingly, the positional information of the first mark is detected by using the compressed image data for this first mark, and then it is possible to obtain the positional information for the second mark with good efficiency based upon the result of this detection.
The mark detection method of the present invention is mark detection method which detects marks (1, 2) upon an object using a mark detection device (9, CONT) which has a predetermined measurement region in which non subject marks (2) are provided at almost equal spacing in the vicinity of the subject mark (1) which is the subject of detection, and the subject mark (2) is detected.
The exposure method of the present invention is an exposure method in which marks (1, 2) upon a substrate (P) are detected using a mark detection device (9, CONT) which has a predetermined measurement region, and a pattern of a mask (M) is exposed to light onto the substrate (P) while positionally aligning the mask (M) and the substrate (P) in which non subject marks (2) are provided at almost equal spacing in the vicinity of the subject mark (1) which is the subject of detection, and the subject mark (1) is detected.
According to the present invention, by providing the non subject marks at almost equal spacing in the vicinity of the subject mark, it is possible to avoid, for example, the inconvenience that, when performing chemical mechanical polishing (CMP) of the device, the surface of the device should contact the polishing surface of the CMP device at an angle, and accordingly it is possible to perform the polishing procedure with good accuracy.
The positional information detection method of the present invention is a positional information detection method in which a subject mark (2) which is formed upon an object (P) is detected using a mark detection device (9, CONT) which detects the mark by a prescribed detection method, and, based upon this detection result, positional information for the object (P) is detected, and a non subject mark (1) which is formed upon the object (P) in a predetermined positional relationship with the subject mark (2), and of which the ease of detection by the predetermined detection method is high, is detected by the mark detection device (9, CONT); based upon the detection result of the non subject mark (1), and the predetermined positional relationship, the subject mark (2) is detected by the mark detection device (9, CONT); and, based upon the detection result for the subject mark (2), positional information for the object (P) is detected.
According to the present invention, when detecting the subject mark, by detecting the non subject mark which has a higher ease of detection and which moreover is in the predetermined positional relationship with respect to the subject mark, after having detected the non subject mark at a high processing speed, it is possible to perform detection of the subject mark with good efficiency, based upon the detection result for the non subject mark and the predetermined positional relationship.
The mark of the present invention is a mark which is formed upon an object, and which is used for detection of positional information of the object. The mark (P1, P2) is arranged in a desired position within a predetermined mark region (A1) which is ensured upon the object (P2), and information is expressed by its position within this mark region.
According to the present invention, since the information is expressed by the positional information of the mark, it becomes possible to express a larger amount of information, as compared to a case in which the information is expressed by the mere presence or absence of a mark.
Furthermore, the mark of the present invention is formed upon an object (P), and is used for detection of positional information for the object, and includes a first mark region (1) and a second mark region (A1) which is in a predetermined positional relationship with the first mark region; and wherein: a first mark is formed within the first mark region for detecting positional information for the object; a second mark (2, P1, P2) is formed within the second mark region and is arranged at a desired position within the second mark region; and information related to the first mark is expressed based upon the position of the second mark within the second mark region.
The exposure device of the present invention is an exposure device which comprises a detector (9) which detects positional information for a substrate by detecting a mark which is formed within a mark region which is made up of a first mark region and a second mark region upon the substrate (P), and a driver (CONT, PST, PSTD) which is electrically connected to the detector, and which shifts the prescribed pattern and the substrate relatively to one another, based upon positional information for the substrate which has been detected by the detector; and which transcribes the prescribed pattern onto a substrate, in which the mark which is detected by the detector comprises: a first mark (1) which, by being detected by the detector, generates a signal which expresses positional information for the substrate by the detector; and a second mark (2, P1, P2) which is arranged at a desired position within a second mark region; and the detector detects information related to the first mark based upon the position of the second mark within the second mark region (A1).
The exposure method of the present invention is an exposure method for transcribing a prescribed pattern onto a substrate (P), comprising: a process of detecting positional information for the substrate by detecting a mark (2) which is formed within a mark region which is made up of a first mark region (1) and a second mark region (A1) upon the substrate; and a process of, based upon positional information for the substrate which has been detected by the detector, shifting the prescribed pattern and the substrate relatively to one another and exposing the prescribed pattern to light; wherein: the mark (2) is a mark which comprises a first mark (1) which causes a position signal for the substrate to be generated by being detected by the detection process, and a second mark (2, P1, P2) which is formed in a desired position within the second mark region, and which expresses information which is related to the first mark by its position within the second mark region; and wherein: information which is related to the first mark is detected based upon the position of the second mark within the second mark region.
The method of manufacturing according to the present invention is a method of manufacturing an exposure device which exposes a prescribed pattern onto a substrate (P), wherein: there is provided a detector (9) which detects positional information for the substrate by detecting a mark which is formed in a mark region which consists of a first mark region (1) and a second mark region (A1) upon the substrate; there is also provided a driver (CONT, PST, PSTD) which shifts the substrate to a position in which the substrate is presented for exposure to light, based upon positional information for the substrate which has been detected by the detector; and wherein: the mark comprises: a first mark (1) which causes a signal which expresses positional information for the substrate to be generated by the detector, by being detected by the detector; and a second mark (2) which is arranged in a desired position within the second mark region; and wherein: the detector (9) detects information which is related to the first mark based upon the position of the second mark (2, P1, P2) within the second region (A1).
According to the present invention, since the information is expressed by the positional information of the mark, accordingly it becomes possible to express a greater amount of information, as compared with a case in which the information is expressed by the mere presence or the absence of a mark.
The mark of the present invention is a mark which is formed upon an object (P), and which is used for detection of positional information of the object, comprising: a vertical pattern portion (
According to the present invention, since the information is expressed by the positional information of the mark, it is possible to express a greater amount of information, as compared with a case in which the information is expressed by the mere presence or absence of a mark. Furthermore since, because the vertical pattern portion extends along the first direction, it is possible to detect the position of the vertical pattern if it is possible to detect a portion anywhere upon the vertical pattern portion, and since, because the horizontal pattern portion extends along the second direction, it is possible to detect the position of the horizontal pattern if it is possible to detect a portion anywhere upon the horizontal pattern portion, and since, from these results, it is possible to obtain the position of the intersection point of the vertical pattern portion and the horizontal pattern portion, accordingly it becomes possible to be lax with the accuracy when relatively positioning the detection area of the detection device with respect to the pattern portion.
The mark of the present invention is a mark which is formed upon an object (P), and which is used for detection of positional information of the object, comprising: a first mark region (1) and a second mark region (A1) which is in a predetermined positional relationship with respect to the first mark region; and wherein: a first mark for detecting positional information for the object is formed within the first mark region; and a second mark (2) which is arranged in a desired position within the second mark region is formed within the second mark region; and the second mark comprises: a vertical pattern portion (
The exposure device of the present invention is an exposure device which comprises a detector (9) which detects positional information for a substrate by detecting a mark which is formed within a mark region which is made up of a first mark region (1) and a second mark region (A1) upon the substrate (P), and a driver (CONT, PST, PSTD) which is electrically connected to the detector, and which shifts the prescribed pattern and the substrate relatively to one another, based upon positional information for the substrate which has been detected by the detector; and which transcribes the prescribed pattern onto a substrate, wherein: the mark which is detected by the detector comprises: a first mark which, by being detected by the detector, generates a signal which expresses positional information for the substrate to the detector; and a second mark (2) which comprises a vertical pattern portion (
The exposure method of the present invention is an exposure method for transcribing a prescribed pattern onto a substrate (P), comprising: a process of detecting positional information for the substrate by detecting a mark which is formed within a mark region which is made up of a first mark region (1) and a second mark region (A1) upon the substrate; and a process of shifting the prescribed pattern and the substrate relatively to one another, based upon positional information for the substrate which has been detected by the detector, and exposing the prescribed pattern to light; wherein the mark comprises: a first mark which, by being detected by the detection process, generates a position signal for the substrate; and a second mark (2) which comprises a vertical pattern portion (
The method of manufacturing of the present invention is a method of manufacturing an exposure device which exposes a prescribed pattern onto a substrate (P) in which there is provided a detector (9) which detects positional information for the substrate by detecting a mark which is formed in a mark region which consists of a first mark region (1) and a second mark region (A1) upon the substrate; there is also provided a driver (CONT, PST, PSTD) which shifts the substrate to a position in which the substrate is presented for exposure to light, based upon positional information for the substrate which has been detected by the detector; and wherein: the mark is a mark which comprises: a first mark which causes a signal which expresses positional information for the substrate to be generated by the detector, by being detected by the detector; and a second mark (2) which comprises a vertical pattern portion (P1) which extends within the second region in a first direction; and a horizontal pattern portion (P2) which extends within the second region in a second direction which intersects the first direction; and wherein: the detector detects information which is related to the first pattern, based upon the position of the intersection point between the vertical pattern portion and the horizontal pattern portion.
According to the present invention, since the information is expressed by the positional information of the mark, it becomes possible to express a greater quantity of information, as compared with the case of expressing the information by the mere presence or absence of a mark. Furthermore since, because the vertical pattern portion extends along the first direction, it is possible to detect the position of the vertical pattern if it is possible to detect a portion anywhere upon the vertical pattern portion, and since, because the horizontal pattern portion extends along the second direction, it is possible to detect the position of the horizontal pattern if it is possible to detect a portion anywhere upon the horizontal pattern portion, and since it is possible to obtain the position of the intersection point of the vertical pattern portion and the horizontal pattern portion, accordingly it becomes possible to be lax with the accuracy when relatively positioning the detection area of the detection device with respect to the pattern portion.
The mark of the present invention is a mark which is formed upon an object, and which is used for detection of positional information for the object comprises a pattern portion which extends within the mark region in a first direction; and wherein: the information is expressed based upon a position which is related to the second direction of the intersection in the first direction of the pattern portion within the mark region.
According to the present invention, since the information is expressed by the positional information of the mark, it becomes possible to express a greater quantity of information, as compared with the case of expressing the information by the mere presence or absence of a mark. Furthermore since, because the pattern portion extends along the first direction, it is possible to detect the position of the pattern if it is possible to detect a portion anywhere upon the pattern portion, accordingly it becomes possible to be lax with the accuracy when relatively positioning the detection area of the detection device with respect to the pattern portion. Yet further, it is possible to simplify the detection process, since it will be acceptable to detect the position of the pattern portion only in relation to the second direction, in other words, only in relation to a single direction.
The mark of the present invention is a mark which is formed upon an object (P), and which is used for detection of positional information for the object: comprising a first mark region (1) and a second mark region (A1) which is in a predetermined positional relationship with respect to the first mark region; and comprising: a first mark which is formed within the first mark region, and which is used for detecting positional information for the object; and a second mark which comprises a pattern portion (
The exposure device of the present invention is an exposure device which comprises a detector (9) which detects positional information for a substrate by detecting a mark which is formed within a mark region which is made up of a first mark region (1) and a second mark region (A1) upon the substrate (P), and a driver (CONT, PST, PSTD) which is electrically connected to the detector, and which shifts the prescribed pattern and the substrate relatively to one another, based upon positional information for the substrate which has been detected by the detector; and which transcribes the prescribed pattern onto a substrate, wherein: the mark which is detected by the detector comprises: a first mark which is formed in the first mark region, and which, by being detected by the detector, generates a signal which expresses positional information for the substrate by the detector; and a second mark (2) which comprises a pattern portion (
The exposure method of the present invention is an exposure method for transcribing a prescribed pattern onto a substrate (P), comprising: a process of detecting positional information for the substrate by detecting a mark which is formed within a mark region which is made up of a first mark region (1) and a second mark region (A1) upon the substrate; and a process of shifting the prescribed pattern and the substrate relatively to one another, based upon positional information for the substrate which has been detected, and exposing the prescribed pattern to light; wherein the mark comprises: a first mark which, by being detected by the detection process, generates a position signal for the substrate; and a second mark (2) which comprises a pattern portion (
The method of manufacturing of the present invention is a method of manufacturing an exposure device which exposes a prescribed pattern onto a substrate (P), wherein: there are provided a detector (9) which detects positional information for the substrate by detecting a mark which is formed in a mark region which consists of a first mark region (1) and a second mark region (A1) upon the substrate, and a driver which shifts the substrate to a position in which the substrate is presented for exposure to light, based upon positional information for the substrate which has been detected by the detector; and wherein: the mark comprises: a first mark which causes a signal which expresses positional information for the substrate to be generated by the detector, by being detected by the detector; and a second mark (2) which comprises a pattern portion (
According to the present invention, since the information is expressed by the positional information of the mark, it becomes possible to express a greater quantity of information, as compared with the case of expressing the information by the mere presence or absence of a mark. Furthermore since, because the pattern portion extends along the first direction, it is possible to detect the position of the pattern if it is possible to detect a portion anywhere upon the pattern portion, accordingly it becomes possible to be lax with the accuracy when relatively positioning the detection area of the detection device with respect to the pattern portion. Yet further, since it will be sufficient to detect the position of the pattern portion only with respect to the second direction, in other words, only with respect to one direction, accordingly it is possible to enhance the simplicity of the detection process.
As in the above, according to the present invention, by providing the second pattern as a combination of n examples of N types of pattern in a predetermined positional relationship with respect to the first pattern for outputting the positional information, and by detecting the shape of this second pattern, even if the same type of marks are present adjacent to the mark which is to be the subject of detection, it is possible to specify the mark which is to be used for position detection from this plurality of marks. And it is possible for the second pattern to display Nn types of information, i.e. a large number, even though the region for arranging the marks upon the substrate is not set to be particularly wide, and, even if a large number of the first patterns of the same type are present, it is possible to perform the mark identification procedure without squeezing down the pattern transcription region upon the substrate. And it is possible to perform the alignment procedure at good accuracy by utilizing this first pattern.
Furthermore, according to the present invention, by detecting the relative positional information of a first pattern and a second pattern of a specified mark, it is possible to obtain information related to the amount of deformation and the amount of rotation of the substrate. Accordingly it is possible, based upon this information which has been obtained, to determine the positions of other marks from the specified mark, and, since it is possible to perform detection of these plurality of marks smoothly, it is possible to enhance throughput.
Furthermore, according to the present invention, when performing mark detection from image data of a mark which are compressed, since the image data of a large non subject mark cannot be squeezed down even if they are subjected to compression processing, accordingly it is possible to detect the positional information of the non subject mark using the compressed image data of this non subject mark, and to obtain the positional information of the subject mark quickly based upon this detection result. Accordingly, it is possible to perform the mark position detection procedure in a short period of time with good efficiency.
Furthermore, according to the present invention, by providing non subject marks at equal spacing around the vicinity of the subject mark, it is possible to avoid the inconvenience that the surface of the device may contact at an inclination with respect to the polishing surface of a CMP device, so that it is possible to perform a polishing procedure with good accuracy. Accordingly, it is possible to manufacture a device which is endowed with the desired functionality.
In the present invention, the mark which is formed on an object and provided with a subsidiary pattern comprises a mark for position detection which detects a position, the subsidiary pattern which is used for identify the mark for position detection which is a target on the object on which a plurality of marks for position detection are formed.
In the present invention, the mark for position detection which is provided with the subsidiary pattern of claim 100, a subsidiary pattern forming area in which the subsidiary pattern is allowed to be formed in a predetermined positional relationship with the mark for position detection, wherein the subsidiary pattern shows an information which identifies the mark for position detection as a target according to whether or not the subsidiary pattern is formed in the subsidiary pattern forming area.
In the present invention, a mark for position detection which is provided with the subsidiary pattern of claim 100 such that the subsidiary pattern shows an information which identifies an identification mark as a target according to a shape of the subsidiary pattern.
In an exposure method of the present invention, the mark for position detection as a target is identified by using the subsidiary pattern from above the object on which the mark for position detection which is provided with the subsidiary pattern of claim 100 is formed, a relational position between a device pattern which is projected on the object and the object is controlled according to a positional information of the object which is obtained as a result of a measurement for the mark for position detection as a target, and a device pattern is transcribed on the object of which relational position is controlled.
In an exposure method according to the present invention, the subsidiary pattern has a predetermined positional relationship which is defined for the mark for position detection, the mark for position detection is measured in a step which identifies the mark for position detection, and after that, an information which identifies the mark for position detection as a target is detected from the identified pattern by using a relational positional information of the subsidiary pattern with reference to the mark for position detection.
In an exposure method according to the present invention, the mark for position detection which is provided with the subsidiary pattern has a predetermined positional relationship with the mark for position detection and is provided with the subsidiary pattern forming area in which the subsidiary pattern is allowed to be formed, and the subsidiary pattern shows an information which identifies the mark for position detection as a target according to whether or not the subsidiary pattern is formed in the subsidiary pattern forming area.
In the present invention, an exposure device which transcribes the device pattern on the object of which relative position is controlled comprises a detection device which detects the mark for position detection from above the object on which the mark for position detection which is provided with the subsidiary pattern of claim 1 is formed, an identification device which identifies the mark for position detection as a target by using the subsidiary pattern, an projection optical system which projects an image of a device pattern on the object, and a position control device which controls the relative position between the image of the device pattern which is projected on the object and the object according to the position information of the object which is obtained as a result of a measurement for the mark for position detection as a target.
In the present invention, a device manufacturing method comprises the steps of identifying the mark for position detection as a target by using the subsidiary pattern from above the object on which the mark for position detection which is provided with the subsidiary pattern of claim 100 is formed, controlling the relative position between the image of the device pattern which is projected on the object and the object according to the position information of the object which is obtained as a result of a measurement for the mark for position detection as a target, and transcribing the device pattern on the object of which relative position is controlled.
In an exposure method according to the present invention, the mark for position detection which is provided with the subsidiary pattern has a predetermined positional relationship with reference to the mark for position detection and is provided with a subsidiary pattern forming area in which the subsidiary pattern is allowed to be formed, and the subsidiary pattern shows an information which identifies the mark for position detection as a target according to whether or not the subsidiary pattern is formed in the subsidiary pattern forming area.
A device of the present invention is manufactured by using the device manufacturing method of the present invention.
In the mark for position detection of the present invention which is provided with the subsidiary pattern of claim 100, the mark for position detection is provided with a plurality of pattern sections which extend to a predetermined direction and are formed periodically, the subsidiary pattern is formed in a part of the pattern section among a plurality of the pattern sections continuously, and the mark for position detection as a target is identified by differentiating a shape of a part of the pattern section among a plurality of the pattern sections from a shape of the other pattern sections among a plurality of the pattern sections.
In the present invention, an exposure method comprises the steps of forming a plurality of marks for position detection according to a positional arrangement such that a positional relationship of a plurality of marks for position detection form a predetermined arrangement, detecting the predetermined arrangement from above the object, specifying the mark for position detection as a target among the marks for position detection which form the predetermined arrangement according to an information for the predetermined arrangement, obtaining an information for the position of the object by using the specified information for the position for the mark for position detection as a target, controlling the relative position between the image of the device pattern which is projected on the object and the object according to the information for the position of the object, and transcribing the device pattern on the object of which relative position is controlled.
First Embodiment
In the following, first embodiments of the mark identification method and the exposure method according to the first embodiment of the present invention will be explained with reference to the figures. This embodiment is one which employs the mark identification method of the present invention in an alignment process (a so called scanning step) of an exposure device which exposes to light a pattern on a mask onto a photosensitive substrate by the step-and-scan method; and
In
The illumination optical system IL is a device which illuminates a mask M which is supported upon the mask stage MST with the exposure light EL, and it comprises a light source, an optical integrator which makes uniform the intensity of the luminous flux which has been emitted from the light source, a condenser lens which collects the exposure light EL from the optical integrator, a relay lens system, a variable field window which sets the illuminated region upon the mask M to a slit shape, and the like. As the exposure light EL which is emitted from the illumination optical system IL, there may be used, for example, an emission line in the ultraviolet region which is emitted from a mercury lamp (the g line, the h line, the i line), and far ultraviolet light (DUV light) such as KrF excimer laser light (of wavelength 248 nm) or the like, or vacuum ultraviolet light (VUV) such as ArF excimer laser light (of wavelength 193 nm) and F2 laser light (of wavelength 157 nm) or the like.
The mask stage MST is a device which supports the mask M, and can be shifted with respect to the base 3 in two dimensions in a plane which is perpendicular to the optical axis AX of the projection optical system PL, in other words in the X-Y plane, and can also be finely rotated. This mask stage MST is driven by a drive device MSTD such as a linear motor or the like, and this drive device MSTD is controlled by a control device CONT which controls the operation of the entire exposure device in an integrated manner.
The projection optical system PL consists of a plurality op optical elements (lenses), and these optical elements are supported upon a lens barrel. In this embodiment, the projection optical system PL is a reduction system whose projection ratio is, for example, 1/4 or 1/5. It should be understood that this projection optical system PL may also be either a equal ratio system or a magnification system. Furthermore, the projection optical system PL comprises an imaging characteristic control device not shown in the drawings which performs compensation of the optical characteristics. This imaging characteristic control device performs compensation of the optical characteristic of the projection optical system PL, such as its projection ratio, its distortion aberration, or the like, by, for example, performing spacing adjustment of a part of the lens group which makes up the projection optical system PL, or by performing gas pressure adjustment within a lens chamber of a part of the lens group. This imaging characteristic control device is controlled by the control device CONT.
The substrate stage PST is a device which supports the photosensitive substrate P, and comprises: an XY stage which determines the position of the photosensitive substrate P upon a stand 5 two dimensionally in a plane which is perpendicular to the optical axis AX of the projection optical system PL, in other words in the XY plane; a Z stage which determines the position of the photosensitive substrate P in the direction which is parallel to the optical axis AX of the projection optical system PL, in other words in the Z axis direction; and a θ stage which finely rotates the photosensitive substrate P.
A shift mirror 6 is provided upon the substrate stage PST. Furthermore, a laser interferometer 7 is provided in a position which confronts this shift mirror 6. The shift mirror 6 consists of a plane mirror which has a vertical reflection plane in the X axis and a plane mirror (not shown in the drawing) which has a vertical reflection plane in the Y axis. The laser interferometer 7 consists of a laser interferometer for the X axis which illuminates a laser beam upon the shift mirror 6 along the X axis and a laser interferometer for the Y axis (not shown in the drawing) which illuminates a laser beam upon the shift mirror along the Y axis, and the position (the X coordinate and the Y coordinate) in the X direction and in the Y direction of the substrate stage PST is measured by these laser interferometers 7 for the X axis and for the Y axis. Furthermore, the rotational angle of the substrate stage PST is measured from the difference between two measurement values by arranging two of the laser interferometers 7 in parallel along one of the X axis and the Y axis. The measurement results for the positional information of the substrate stage PST due to these laser interferometers 7, such as its X coordinate, its Y coordinate, its rotational angle and so on, are outputted to the control device CONT, and the control device CONT controls the position determination operation of the substrate stage PST via the drive device PSTD such as a linear motor or the like while monitoring this positional information. Although this matter is not shown in
The exposure device EX comprises an alignment optical system (a position detection device or mark detection device) 9 which is disposed separately from the projection optical system PL, and which utilizes an off-axis method. This alignment optical system 9 is provided with a rectangular shaped measurement region, and irradiates broadband light of wavelength about 550˜750 nm which is emitted by, for example, a halogen lamp upon alignment marks (marks for position detection) which are provided upon the photosensitive substrate P, and detects an image of indicator marks which are arranged upon a surface which is conjugate to the surface of the photosensitive substrate and an image of the alignment marks which are present within the measurement region with a photographic element (a CCD). The control device CONT, after aligning the image of the pattern upon the mask M and a shot region upon the photosensitive substrate P using the alignment optical system 9, along with scanning the mask stage MST in a direction which is perpendicular to the optical axis AX of the projection optical system PL (in this embodiment, the +X direction), synchronously with this, scans the substrate stage PST in, for example, the opposite direction (the −X direction) at a speed ratio which is the same as the projection magnification of the projection optical system PL, and sequentially transcribes (exposes to light) the pattern image upon the mask M to each of the shot regions upon the photosensitive substrate P.
Next, while referring to
As shown in
The identification mark 2 is a mark for identifying, among the plurality of alignment marks 1 which are provided upon the photosensitive substrate P, that alignment mark 1 which should be used in the alignment procedure, and is provided in association with each of the plurality of alignment marks 1. The identification mark shown in
Here, with the identification mark 2 shown in
With the identification mark 2 shown in
Furthermore, the control device CONT obtains the coordinates of the alignment mark 1 in the stage coordinate system based upon the results of measurement of the substrate stage PST which are outputted by the laser interferometers 7 for the X axis and for the Y axis when the alignment mark 1 has been photographed. This type of technique for photographing an image of the alignment mark 1 with the photographic elements to obtain the coordinate values of the alignment mark 1 is termed the FIA (Field Image Alignment) type, and, in this embodiment, it will be supposed that an alignment process of the FIA type using the alignment optical system 9 is performed, and furthermore that the alignment mark which consists of lines and spaces which is used in this embodiment is a two dimensional mark which is detected by the alignment detection system of the FIA type, so that it is possible to perform position detection in the X axis direction and in the Y axis direction with a single mark. It should be understood that although, in the above explanation, it has been assumed that it is a FIA type system which images the image of the alignment mark 1 upon the indicator plate, it would be the same if the construction were to be such that the indicator plate was arranged upon another optical path from the optical path of the detection light for alignment, and the image of the alignment mark and the image of the indicator mark were imaged upon a photographic element.
Next, a method for detecting an alignment mark which is formed upon the photosensitive substrate P by using the exposure device EX which comprises the alignment optical system (position detection device) 9 having the above described structure, and for performing processing for exposure to light, will be explained while referring to
First, the mask M and the photosensitive substrate P are carried to the mask stage MST and the substrate stage PST respectively. Here, when carrying the photosensitive substrate P to the substrate stage PST and supporting it thereupon, preliminary position alignment of the photosensitive substrate P with respect to the substrate stage PST is performed (in the step S1) using an orientation flat or a notch or the like, according to the physical shape of the photosensitive substrate P, for example if the photosensitive substrate P is a wafer.
It should be understood that although, here, the positional alignment when carrying the photosensitive substrate P to the substrate stage PST and supporting it thereupon is termed a “pre-alignment procedure”, it could also be the case that a preliminary positional alignment is performed using the physical shape of the photosensitive substrate P, upon the substrate transportation path, before the photosensitive substrate P is supported upon the substrate stage PST; or it could be the case that a preliminary positional alignment is performed using the physical shape of the photosensitive substrate P, both upon the transport path before the photosensitive substrate P is supported upon the substrate stage PST, and also directly before the photosensitive substrate P is supported upon the substrate stage PST; and such procedures are also termed “pre-alignment procedures”.
Next, the exposure device CONT decides (in the step S2) whether this processing of the photosensitive substrate P for exposing it to light is the first episode of processing for exposure to light or not, in other words whether this is the first layer of pattern transcription for the photosensitive substrate P, or whether it is the second or a subsequent layer of pattern transcription.
If it is decided that this is the first episode of processing for exposure to light, then the control device CONT, while shifting the mask stage MST which supports the mask M and the substrate stage PST which supports the photosensitive substrate P in synchrony with one another, also illuminates the mask M with the exposure light EL by the illumination optical system IL, and thus exposes to light the pattern upon the mask M via the projection optical system PL onto each of the shot regions of the photosensitive substrate P (in the step S8).
At this time, the shot arrangement is performed based upon the design data (the shot map data).
On the other hand, if in the step S2 it is decided that this is the second or a subsequent episode of processing for exposure to light for the photosensitive substrate P, then the control device CONT detects the mark within the measurement region with the alignment optical system 9 (in the step S3).
Here, as will be explained subsequently using
And, when the control device CONT has specified those alignment marks from the plurality of alignment marks which are to be used in the alignment procedure, it detects the positions (the coordinate values in the stage coordinate system) of these alignment marks which it has specified (in the step S5).
Next, the control device CONT determines whether or not it has detected the position of the prescribed number of alignment marks (in the step S6).
If in the step S6 it is decided that the prescribed number has not been reached, then the control device CONT returns to the step S3. On the other hand, if it is decided that the prescribed number has been reached, then the control device CONT performs a statistical calculation procedure (an EGA procedure or the like) using the detected positions of the plurality of alignment marks, and performs position calculation of each of the shot regions (in the step S7).
And, having detected the positions of the predetermined alignment marks upon the photosensitive substrate P with the alignment optical system, and having performed positional alignment of the mask M and a shot region upon the photosensitive substrate P based upon a base line amount which is regulated in advance, the control device CONT shifts the photosensitive substrate P in order according to the calculated positions of each of the shot regions which were calculated in the step S7, and exposes the pattern image upon the mask M to light with the exposure light EL and projects it in the state in which the pattern image upon the mask M has been accurately superimposed upon and aligned with each of the shot regions. At this time, the base line amount which is used in the step S8 is measured in advance using a standard mark FM (refer to
It should be understood that the alignment procedure is constituted by a series of episodes of performing the steps S3 through S7, in which a plurality of alignment marks upon the photosensitive substrate P are detected and the detection of the position of each shot region (the EGA processing) is performed.
Here, upon the photosensitive substrate P, it may happen that a plurality of alignment marks are formed in respective correspondence to a plurality of shot regions; for example, it may happen that the respective alignment marks which have been provided corresponding to shot regions which adjoin one another may be disposed close to one another. In this case, it may happen that the alignment optical system 9 contains together this plurality of alignment marks which are close to one another within the measurement region at the same time.
As shown in
Furthermore, a layered structure in which a plurality of layers are provided is formed upon the substrate: the alignment marks 1A and 1E are alignment marks which are formed upon the topmost layer (hereinafter for convenience termed the “No. 3 layer”); the alignment marks 1B and 1D are alignment marks which are formed upon the previous layer, in other words upon the layer below the No. 3 layer (hereinafter for convenience termed the “No. 2 layer”); and the alignment mark 1C is an alignment mark which is formed upon the previous to the previous layer, in other words upon the layer below the No. 2 layer (hereinafter for convenience termed the “No. 1 layer”). Since, in this manner, the fact that the alignment marks are in the state of being near to one another is because an alignment mark which is formed upon a previous layer is being observed, accordingly, in
And, with the identification mark 2 which is associated with the alignment mark 1A, the character pattern A is provided in the region R1, the character pattern B is provided in the region R2, the character pattern C is provided in the region R3, and the character pattern A is provided in the region R4. Furthermore, with the identification mark 2 which is associated with the alignment mark 1C, the character pattern A is provided in the region R1, the pattern B is provided in the region R2, the character pattern A is provided in the region R3, and the character pattern C is provided in the region R4. Moreover, with the identification mark 2 which is associated with the alignment mark 1E, the character pattern A is provided in the region R1, the character pattern B is provided in the region R2, the character pattern C is provided in the region R3, and the character pattern C is provided in the region R4. On the other hand, with the identification marks 2 which are associated with the alignment marks 1B and 1D, no character pattern is present in any of the regions R1 through R4. In this manner, the alignment marks 1A through 1E and the identification marks 2 which are associated with them are formed upon each of the layers, and the identification marks 2 are provided so that the information which is specified by the identification marks 2 is different for each of the layers.
In the following the case will be explained of aligning, in the step S4 shown in
Here, process data containing information relating to the alignment marks which are to be the subjects of position detection (detection subject marks), shot map data including positional data for each shot region upon the photosensitive substrate P and positional data for the marks within each shot region, and mark information are stored in advance in the control device CONT (or in a storage device connected thereto).
The process data, for example, includes information such as “the alignment mark 1A is an alignment mark which is used in the alignment procedure when superimposing a subsequent layer circuit pattern over the No. 3 layer”. Accordingly, when performing processing for light exposure by using the mask M which includes the circuit pattern for the subsequent layer, the control device CONT refers to this process data, and performs the alignment procedure after determining upon all the alignment marks which are to be used (the marks which are to be the subjects of detection).
In the mark information, for example, there may be included information related to the forms and the positions of disposition of the three types of pattern A through C in the identification marks which are respectively associated with the plurality of alignment marks 1A through 1E, like “if, respectively, the character pattern A is disposed in the region R1, the character pattern B is disposed in the region R2, the character pattern C is disposed in the region R3, and the character pattern A is disposed in the region R4, then this alignment mark is 1A”. The control device specifies that the alignment mark 1A is that subject mark which has been detected from the plurality of alignment marks 1A through 1E by referring to this mark information.
First, the control device CONT, as described above, detects the marks within the measurement region of the alignment optical system 9 (in the step S3).
Here, the control device CONT, along with determining the mark 1A which is to be the subject of detection by referring to the process data, also reads out the coordinate values of the mark 1A which is to be the subject of detection from the shot mark data, and drives the substrate stage PST based upon these coordinate values, and performs control so as to move this mark 1A which is to be the subject of detection into the measurement region of the alignment optical system 9. And the control device CONT performs mark detection by taking in and image processing the luminance data within the measurement region of the alignment optical system 9.
The control device CONT first makes a decision (in the step S11) as to whether or not one or more alignment marks have been detected within the measurement region of the alignment optical system 9.
In other words, since the positional accuracy of the photosensitive substrate P is low because its position is determined during the pre-alignment in the step S1, it sometimes happens that no mark is detected within the measurement region of the alignment optical system 9. Due to this, the control device CONT makes a decision as to whether or not there is a mark within the measurement region.
In the step S11, if it has been decided that no mark has been detected within the measurement region, the control device CONT makes a decision (in the step S12) as to whether or not the number of times that the measurement region has changed has reached a prescribed number of times.
In the step S12, if it is decided that the number of changes of region has reached a prescribed number of times, the control device CONT provides an error display. On the other hand, if it is decided that the number of changes of region has not reached the prescribed number of times, the control device CONT changes the measurement region (in the step S13).
And the control device performs mark detection using the alignment optical system 9 for the measurement region which has been changed (in the step S3).
It should be understood that the change of measurement region in the step S13 includes a procedure of taking the target coordinate value (the coordinate value of the mark 1A which is the subject of detection according to the shot map data) as a center, and changing to a lower or higher magnification by adjusting the alignment optical system 9 with respect to the measurement region, or a procedure of adding on a predetermined offset which is based upon the coordinate values of the subject mark for detection 1A from the shot map data as a compensation coordinate value, and shifting the measurement region based upon this compensation coordinate value, or the like.
On the other hand, in the step S11, if it has been decided that a plurality of alignment marks have been detected within the measurement region (in other words, if the situation has arrived at the one shown in
In other words, as has been explained using
Next, the control device CONT obtains (in the step S15) the respective positions of the identification marks 2 which are associated with each of these alignment marks 1A through 1E from the specified positions Oa through Oe of the alignment marks 1A through 1E which have been obtained in the step S14.
In other words, as shown in the schematic figure of
It should be understood that although, in this embodiment, the structure is such that the respective relative position of each of the regions R1 through R4 with respect to the central position O of the alignment mark 1 is obtained, it would also be acceptable, for example, to obtain the position (the relative position) OR1 of the region R1 which corresponds to the central position O of the alignment mark 1, and to obtain the respective positions (the relative positions) OR2 through OR4 of the regions R2 through R4 with respect to this position OR1 of the region R1 which has been obtained.
Next, the control device CONT observes, using the alignment optical system 9, each of the regions JR1 through R4 of the identification mark 2 which was obtained in the step S15, and detects the character patterns A through C which are respectively arranged in each of these regions R1 through R4 (in the step S16).
The control device CONT detects, using the alignment optical system 9, the images of the character patterns A through C which are formed in each of the regions R1 through R4 of the respective identification marks 2 which are associated with the alignment marks 1A through 1E which were obtained in the step S15, image processes these observed images, and obtains the forms (the shapes) of the character patterns which are respectively arranged in each of the regions R1 through R4. Here, the control device CONT compares together standard images which are stored in advance as mark information, and the observed image which has been detected by the alignment optical system, and, by a pattern matching method which derives the degree of similitude of these two images, obtains the shape of the character patterns which are disposed in each of these regions R1 through R4. Since the identification mark 2 is made up of a character pattern which displays 34 types of information when the observed image which has been observed by the position detection device of the image processing method which includes the alignment optical system 9 and the control device CONT has been image processed, accordingly the control device CONT performs image processing based upon the results of detection by the alignment optical system 9, and is able to obtain the shape of the character pattern based upon a pattern matching method.
Next, the control device CONT refers to the mark information, and, based upon the information related to the shape and the positioning of the character pattern of the identification mark 2 which has been obtained in the step S16, specifies, from the plurality of alignment marks 1A through 1E, the mark 1A which is to be the subject of detection using the alignment procedure (in the step S17).
And the control device CONT determines that the alignment mark which is used in the alignment procedure is 1A.
When it has determined that the alignment mark which is used in the alignment procedure is 1A, the control device CONT aligns the mask M and the shot region SH1 of the photosensitive substrate by using this alignment mark 1A (in the step S5).
In the following, after having performed position calculation for each shot region, as has been explained using
As has been explained above, by providing the identification marks 2 so as to associate them in a predetermined positional relationship with respect to the alignment marks 1 for outputting the positional information for the photosensitive substrate P (the shot regions), by detecting the form of this identification mark 2, even if the same types of alignment mark 1B through 1E are present adjacent to the alignment mark 1A which is to be the subject of detection, it is possible to specify, from this plurality of alignment marks 1A through 1E, that alignment mark 1A which must be used in the alignment procedure. And, since the identification mark 2 is made up as a combination of four by disposing the three types of character pattern respectively in the four regions R1 through R4, it is possible to display the large number 34 of types of information even without setting the region for formation of the alignment marks for disposing the alignment mark 1 upon the photosensitive substrate P to be wide, so that it is possible to identify the mark without narrowing down the region for circuit pattern formation upon the photosensitive substrate P, even if a large number of alignment marks of the same type are present within the measurement region in which a large number of alignment marks are formed for each layer.
It should be understood that although, in the above described embodiment, a structure is implemented in which the respective positions Oa through Oe of the plurality of alignment marks 1A through 1E within the measurement region are obtained, and, based upon this positional information which has been obtained, the position of the identification mark 2 (the positions of the regions R1 through R4) are obtained while referring to the mark information, and the forms of the character patterns A through C which are respectively disposed in these regions R1 through R4 are obtained by a pattern matching method, it would also be acceptable, without performing position detection of the alignment marks 1A through 1E, to determine the positions of each of the identification marks 2 based upon the shot map data, and to specify the identification mark 2 by performing character pattern detection. And, since the identification marks 2 and the alignment marks 1 are arranged in a predetermined positional relationship, it is possible to specify that alignment mark 1A which must be utilized in the alignment procedure based upon the positional information for the identification mark 2 which has been specified.
In the above described embodiment, the character patterns are the alphabetic characters A through C, but of course they are not limited to being alphabetic characters; it would be acceptable for them to be patterns which specify Nn types of information when the observed image which has been observed by the position detection device of the image processing method has been image processed; for example, it would be acceptable to inscribe the digits “1”, “2”, and “3”, or to inscribe characters including hiragana (conventional Japanese syllabic letter) or katakana (modified Japanese syllabic letter), or patterns such as “◯”, “Δ”, and “□”.
Although, in the above described embodiment, the structure was such that the identification marks 2 included the four regions R1 through R4, and one thereof was provided for each one of the alignment marks 1, it would also be acceptable, as shown in
Next, the second embodiments of the mark for position detection and the mark identification method of the present invention will be explained with reference to
In
In the example shown in
When specifying that alignment mark 1, from the plurality of alignment marks 1 with which these bit marks 30 are associated, which should be utilized in the alignment procedure, the control device CONT detects the respective specified positions O of the plurality of alignment marks 1 by the same procedure as was explained using
Since, in this manner, it is arranged to identify the identification mark 2 according as to which regions, among the four regions R1 through R4, patterns are provided in and which regions patterns are not provided in, therefore, even if, as for example in the example shown in
It should be understood that although, in the above described example, the case was explained in which the identification mark 2 was identified according as to which regions, among the regions R1 through R4, a bit mark 30 was provided in and which regions a bit mark 30 was not provided in, it is also possible, for example, after having detected the number of the bit marks 30, to detect the position with respect to the specified position of, for example, an edge portion or the like of the alignment mark 1 for each of these bit marks 30 which have been detected, and to identify a identification mark 20 based upon the number of bit marks 30 and their arrangement (the number and the arrangement of the regions in which the bit marks 30 are provided). Furthermore, instead of obtaining the relative positions of each of the regions R1 through R4 with respect to the specified position of the alignment mark 1 (the relative positions of the bit marks 30 with respect to the specified position of the alignment mark 1), it would also be acceptable to obtain the relative position of each of the regions R1 through R4 itself, and to identify the identification mark 2 based upon these relative positions of the regions R1 through R4 themselves which have been obtained, and upon the number of the bit marks 30.
As has been explained above, a structure is also possible in which the identification mark 2 is built up by arranging respective bit marks 30 for each of n regions R1 through Rn; and, by doing this, it is possible to specify 2n types of information. And, by building up the identification mark 2 with the bit marks 30, there is no requirement for complicated image processing like a so called pattern matching method—in which feature this embodiment is different from the first embodiment—so that it is possible to perform the mark identification with a comparatively simple image processing procedure.
Next, the third embodiment of the present invention will be explained with reference to
In
In other words although, as described above, the bit marks 30 are detected by scanning the photographic element for the X axis and the photographic element for the Y axis, if, for example, as shown in
It should be understood that although, in this embodiment, each of the regions R1 through R4 is set to a position in which they do not overlap either in the X axis direction or in the Y axis direction, it would also be acceptable to set them to positions in which they did not overlap in one of either the X axis direction or the Y axis direction.
Next, the fourth embodiment of the present invention will be explained with reference to
As shown in
It should be understood that, in the identification mark 2, apart from continuation in the pattern portions 12L of the marks 12 for X detection, continuation is also possible in the pattern portions 11L of the marks 11 for Y detection. For example, in the example shown in
It should be understood that, apart from forming identification marks by extending the lengths in the extension direction of the patterns for detection, as in this embodiment, it might also be considered to increase the number of patterns for detection. For example although, in this embodiment, the pattern portions 12L are formed on both sides of the mark 11 for Y detection at each third line portion, it would also be possible, by forming them with four lines at one side and three lines at the other side, or by forming four lines at each side, to identify them from marks in which three line portions at each side are formed.
Furthermore, if there is a dedicated X axis direction (or Y axis direction) detection mark 23 like the one shown in
Next, the fifth embodiment of the present invention will be explained with reference to
In
It should be understood that, by detecting the shape of this mark for perception by a pattern matching method, it is possible to identify the alignment mark 1 based upon the result of this detection. In other words, it is also possible to utilize the mark for perception as the identification mark 2.
Next, the sixth embodiment of the present invention will be explained with reference to
In this embodiment, a identification mark 2 is not provided to each of the alignment marks 1; the alignment optical system 9 specifies the detection subject mark from the alignment marks 1A through 1E which have been detected in the measurement region by utilizing an alignment procedure, based upon information related to the arrangement of the plurality of the alignment marks 1 which are detected within the measurement region. In the following explanation, the case of specifying the alignment mark 1A from the plurality of alignment marks 1A through 1E will be explained.
As shown in
The control device CONT refers to the mark information an specifies the alignment mark 1A which is to be the detection subject mark from the arrangement of the central positions Oa through Oe which has been obtained. In other words, the control device CONT obtains each of the mutual relative positions of the central positions Oa through Oe, and, as shown by the solid lines in
It should be understood—although it is clear from
It should be understood that although, in this embodiment, the relative positions of a plurality of alignment marks 1A through 1E are specified, and the detection subject mark is specified from this relative positional information, it would also be acceptable to arrange, for example, to obtain the respective relative positions of the alignment marks 1A through 1E with respect to the specified position of the circuit pattern which is formed upon the shot region (refer to the symbol K in
Next, the seventh embodiment of the present invention will be explained while referring to
The circuit pattern, the alignment mark, and the identification mark formed upon the mask M are transcribed onto a resist of the previous layer of the photosensitive substrate P by processing it by exposure to light. An image of the circuit pattern, the alignment marks, and the identification marks is formed upon the previous layer of the photosensitive substrate P (in the step SA1).
Development processing is performed upon the photosensitive substrate P upon which the image of the alignment marks and the identification marks has been transcribed. By this development processing, the alignment marks 1 and the identification marks 2 are formed in a predetermined positional relationship (in the step. SA2).
The photosensitive substrate P upon which the resist has been applied over the previous layer, after having been pre-aligned, is transported to the substrate stage PST of the exposure device EX. The control device CONT performs detection of the alignment marks 1 and the identification marks 2 which are formed upon the photosensitive substrate P by using the alignment optical system 9 (in the step SA3).
Here, as shown in
Furthermore, from the relative positional information which it has detected, the control device CONT obtains (in the step SA5) the amount of change of the distance between the alignment mark 1 and the identification mark 2 from the time point at which the alignment mark 1 and the identification mark 2 were formed upon the photosensitive substrate P until the relative positional information is detected, or the amount of rotation of the photosensitive substrate P (the shot region) in a prescribed direction.
In other words, as shown in
The control device CONT compensates the design position of the other alignment marks based upon the scaling and rotation which have been obtained (in the step SA6).
The control device CONT determines the position of the alignment marks other than the alignment mark 1 which has been detected based upon the compensation amount (in the step SA7).
That is to say, it is possible to utilize the alignment mark 1 as a search alignment mark, and, in such a case, as shown in the schematic view of
When the alignment procedure has been completed, the exposure device EX exposes the circuit pattern upon the mask M to light onto the subsequent layer upon the photosensitive substrate P (in the step SA8).
It should be understood that, in this embodiment, the detection of the relative positional information of the alignment mark 1 and the identification mark 2 has been explained as being performed at the time of the search alignment procedure, but it would also be acceptable, for example, to perform it at the time of the pre-alignment procedure.
Furthermore although, in this embodiment, the scaling information and so on was obtained by detecting the specified position O1 of the alignment mark 1 and the specified position O2 of the identification mark 2, from the point of view of accuracy, it is more desirable, when obtaining the scaling information and the rotation information, for the distance between the two detection points to be great. Thus, it is desirable to form a second identification mark at a position which is the symmetric point to the identification mark 2 when the center of the alignment mark 1 is taken as the point of symmetry, and to obtain the scaling information and the rotation information and so on from the specified position of this second identification mark, and the specified position O2 of the original identification mark 2. Yet further, the same beneficial result may also be obtained by increasing the distance between the alignment mark 1 and the identification mark 2.
Next, the eighth embodiment of the present invention will be explained with reference to
If the alignment mark 1 and the identification mark 2 shown in
In this case, as shown in
As has been explained above, when detecting a identification mark 2 which is smaller than the alignment mark 1, by detecting an alignment mark 1 which can be easily detected by the mark detection device, in other words which has a greater surface area than the identification mark 2 and whose ease of detection is high, and which moreover is in the prescribed positional relationship with the identification mark 2, after detecting the alignment mark 1 with high speed processing, it is possible to perform detection of the identification mark 2 with good efficiency, based upon the detection result of the alignment mark 1 and the prescribed positional relationship.
It should be understood that although, in this embodiment, the detection method is one which detects the position of the alignment mark 1 which is larger than the identification mark 2 which is the detection subject mark, and detects the position of the identification mark 2 based upon the result of this detection, it would also be acceptable, as a detection method, to detect the positional information for a non subject mark which is in a predetermined positional relationship with respect to the detection subject mark and moreover for which, for example, the luminance data of the image which is photographed by the alignment optical system is alike, and to perform position detection of the detection subject mark based upon this detection result. Here, by a mark of which the luminance data is alike, is meant a mark for which the value of the scattering of the image data (the luminance data) is small, and the control device CONT is able to detect in a short time period the position for which the scattering value is the smallest in the measurement region of the alignment optical system (the photographic element), in other words the position of the non subject mark. In this manner, if the non subject mark is in a predetermined positional relationship with respect to the detection subject mark, and has a shape for which position detection is possible at high speed (the ease of detection is high) according to the image processing method of the mark detection device (the detection method), then, by performing position detection of this non subject mark, based upon the result of this detection, it is possible to detect the position of the subject mark in a short time period.
Next, the ninth embodiment of the present invention will be explained with reference to
As shown in
It should be understood that here by “spacing” is meant that, in
Although sometimes a CMP (chemical-mechanical polishing) procedure may be performed for flattening the surface of the photosensitive substrate P (the device surface) by employing this type of structure, as shown in the schematic view of
It should be understood that, instead of providing the non subject marks 2 at an equal spacing around the vicinity of the subject mark 1, it would also be acceptable to arrange to protect the subject mark 1 by providing partition portions around the vicinity of the subject mark 1 and made from the same substance as the subject mark 1. Furthermore, if the line width of the subject mark 1 is minute, when image processing such as was described in the eighth embodiment described above is performed upon the image data, or when observation is performed by using an optical system of low magnification which can observe a wide area upon the substrate, it may happen that it is not possible to perceive the subject mark quickly. To address this matter, if the line width of the partition portions which are provided for protection of the subject mark 1 is made to be thicker than the line width of the subject mark 1, then satisfactory results can be obtained, even in the case that the image data is compressed, or that the marks are observed by employing an optical system of low magnification.
Next, the tenth embodiment of the present invention will be explained with reference to
As shown in
In the following, the method of giving information in this embodiment will be explained, with reference to
With the second mark 2 shown in
As described above, by changing one or both of the horizontal position of the vertical pattern P1 and the vertical position of the horizontal pattern P2, the positions of the intersection points between the vertical pattern P1 and the horizontal pattern P2 are mutually changed, as in
It should be understood that the alignment optical system for detecting the alignment mark which is formed in the alignment mark region 1—for example, the alignment optical system 9 which comprises a photographic element as shown in
Furthermore, although the fact that variations of the horizontal position of the vertical pattern P1 and of the vertical position of the horizontal pattern P2 are related to the resolving power of the detection device has already been discussed, if the desired resolving power is not obtained by the alignment optical system which comprises the photographic element due to the influence of processes such as so called mark low level differences and the like, it sometimes happens that the desired resolving power can be obtained by making good use of the gain adjustment function of the photographic element, in other words, of the function of varying the amplitude of the signal which is generated from the photographic element. Moreover, if an alignment device is utilized which is endowed with the function of varying the wavelength of the alignment light which illuminates the alignment marks according to the characteristics of the resist which is applied to the wafer, then it will also be acceptable to take good advantage of this wavelength changeover function when detecting the second marks 2. As described above, by varying the detection conditions when detecting the second mark 2 according to the influence of processes and the characteristics of the resist, it becomes possible to obtain a higher resolving power with the detection device, and accordingly it is possible to increase the variation of the horizontal position of the vertical pattern P1, and the variation of the vertical position of the horizontal pattern P2, of this embodiment, and it becomes possible to express a greater amount of information.
It should be understood that although, in
Yet further, although in
The Application of the Tenth Embodiment to the Search Mark
Now, as the search mark which was previously described in the section relating to the prior art, a mark such as shown, for example, in
The search mark 50 includes three vertical patterns P1L, P1C, and P1R which extend in the vertical direction so as to be mutually parallel to one another, and two horizontal patterns P2A, P2C, and P2U which extend in the horizontal direction so as to be mutually parallel to one another, and is made so as to define 9 intersection points in which the three vertical patterns and the three horizontal patterns overlap with one another. Among these vertical patterns which extend in the vertical direction so as to be mutually parallel to one another, the central pattern P1C may be positioned at any desired position between the left and right vertical patterns P1L and P1R, and, among the horizontal patterns which extend in the horizontal direction so as to be mutually parallel to one another, the central pattern P2C may be positioned at any desired position between the left and right vertical patterns P2A and P2U. And, by establishing a correspondence between different items of information and the position of each of the intersection points, it is possible to indicate a large number of items of information, in the same way as with the tenth embodiment described above.
Although this idea has already been described for the prior art, in order to prevent detection errors for the search mark, a forbidden zone is provided in which formation of the same type of pattern in the vicinity of the search mark is prohibited, and, by applying the concept of the tenth embodiment as described above to the search mark, and making the position of the intersection point of the vertical pattern P1C and the horizontal pattern P2C to be different for each layer, it becomes possible to identify the search mark which must be detected.
Next, the eleventh embodiment of the present invention will be explained with reference to
As shown in
In the following, the method of displaying information will be explained in relation to the second mark which is positioned at the upper right of the drawing paper in
With the second mark 2 shown in
As described above, by making one or both of the horizontal position of the first pattern portion within the first separated region A1 and the horizontal portion of the second pattern portion P2 within the second separated region A2 to be different, it becomes possible to display a large number of items of information, equal to the number of combinations of the horizontal position of the first pattern P1 and the horizontal position of the second pattern P2. Accordingly, in the same manner as in the tenth embodiment described above, as compared with a identification mark which utilizes a bit mark, it becomes possible to make a great leap forward in increasing the number of items of information which can be displayed.
Furthermore, with the second mark of the tenth embodiment described above, it was necessary to detect the horizontal position within the second mark region for the vertical pattern portion, and to detect the vertical position within the second region for the horizontal pattern portion. However, there are some detection devices used in photographic elements which can only detect positional information in one direction. Granted that this type of detection device is used, when performing detection of the second mark of the tenth embodiment shown in
By contrast to this, with the second mark 2 of the eleventh embodiment shown in
Furthermore although, in the above explanation of the embodiment, a structure has been explained in which, after mainly having specified the detection subject mark, the subsequent procedures such as positional alignment and so on are performed by using the positional information of the mark which has been specified; but the present invention is not to be considered as being limited thereby; a structure would also be acceptable such as, for example, one in which, after having detected a specified mark, positional information was detected from that specified mark for a different mark from the specified mark which was in a predetermined positional relationship thereto, and the subsequent procedures were performed using the positional information for that different mark.
Furthermore, it is also possible to utilize the embodiments explained above in combination. For example, along with providing a identification mark 2 which is made up from bit marks 30 in the vicinity of the alignment mark 1 of the second embodiment, it would also be acceptable to arrange the identification mark 2 along the extension of the direction of extension of the pattern portion of the alignment mark 1 of the fourth embodiment. Yet further, if the pattern information of the circuit pattern portion which is formed in the shot region is combined, it becomes possible to display even more types of information.
It should be understood that, as the exposure device EX of this embodiment, apart from an exposure device of the scanning type which exposes the pattern upon the mask M to light by shifting the mask M and the photosensitive substrate P in synchronism, it would also be possible to apply the present invention to an exposure device of the step and repeat type, which exposes the pattern upon the mask M in a state in which the mask M and the photosensitive substrate P have both been stopped, and which successively step shifts the photosensitive substrate P. Furthermore, as the exposure device and the mark for position detection of this embodiment, it would also be possible to apply the present invention to a proximity exposure device which exposes the pattern upon the mask M to light by closely contacting together the mask M and the photosensitive substrate P without employing any projection optical system PL.
The utility of the exposure device EX is not limited to the exposure device for manufacturing semiconductors; it could also be applied in a wide context—for example, to an exposure device for a liquid crystal which exposes a liquid crystal display element pattern upon a square glass plate to light, or to an exposure device for manufacturing a thin film magnetic head.
As the projection optical system PL, it will be acceptable, if far ultraviolet light such as that from an excimer laser or the like is used, to utilize a material which is transparent to far ultraviolet rays such as quartz or fluorite or the like as the nitrate??; if an F2 laser or an X-ray beam is used, to utilize an optical system of the reflection-refraction type or of the refraction type (for the mask, a reflection type is also used); or, if an electron beam is used, to utilize an electronic optical system consisting of an electronic lens and a deflector as the optical system. It will be understood that it is not necessary to state that the optical path which the electron beam traverses is brought to the vacuum state.
If linear motors are used for the substrate stage PST and/or the mask stage MST, it will also be acceptable to utilize either an air floating type which uses air bearings, or a magnetic floating type which uses Lorentz force or reactance force. Furthermore, for the stage, either a type which shifts along guides, or a guideless type in which no guides are provided, is also acceptable.
If a planar motor is utilized as the drive device for the stage, either one of the magnetic unit (the permanent magnet) and the armature unit may be connected to the stage, and the other of the magnetic unit and the armature unit may be provided to the shift surface side (the base) of the stage.
The reaction force which is generated by the shifting of the substrate stage PST, as is described in Japanese Unexamined Patent Application, First Publications No. Hei 8-166475, may be allowed to escape to the floor (the ground) mechanically using a frame member. The present invention may also be applied to an exposure device which has this type of structure.
The reaction force which is generated by the shifting of the mask stage MST, as is described in Japanese Unexamined Patent Application, First Publications No. Hei 8-330224, may also be allowed to escape to the floor (the ground) mechanically using a frame member. The present invention may also be applied to an exposure device which has this type of structure.
As described above, with the exposure device of the embodiment of the present application, each type of sub-system, including each mechanical element which is enumerated in the scope of the claims of this patent, is manufactured by assembly so as to preserve a predetermined mechanical accuracy, electrical accuracy, and optical accuracy. In order to ensure these various types of accuracy, before and after this assembly, adjustment is performed in order to arrive at optical accuracy for the various optical systems, adjustment is performed in order to arrive at mechanical accuracy for the various mechanical systems, and adjustment is performed in order to arrive at electrical accuracy for the various electrical systems. The process of assembly from the various sub-systems to the exposure device includes, between the various types of sub-system, mechanical connection, wiring connection of the electrical circuitry, conduit connection of air pressure circuits, and the like. It goes without saying that, before the process of assembly from these various types of sub-system to the exposure device, there is a process of assembling each of the sub-systems. When the process of assembly from these various types of sub-system to the exposure device has been completed, overall adjustment is performed, and thereby the various types of accuracy as an integrated exposure device are assured. It should be understood that it is desirable to perform the manufacture of the exposure device in a clean room in which the temperature and the degree of cleanliness are appropriately managed.
As shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| P 2002-095562 | Mar 2002 | JP | national |
| P 2002-242457 | Aug 2002 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP03/04019 | Mar 2003 | US |
| Child | 10950450 | Sep 2004 | US |
