Patent Application
20130068726
The present invention relates to a plasma processing apparatus such as a dry etching apparatus or a CVD apparatus.
In connection with plasma processing apparatuses, wafers as objects to be processed are held by a support pedestal, which is referred to as a susceptor and is provided in a chamber. Next, a high-frequency voltage is applied to the chamber in the air-tight state, while gas for generating plasma is supplied, so as to generate plasma in the chamber. By exposing the wafers to plasma, the wafers are subjected to plasma processing such as dry etching.
With such a plasma processing apparatus, in order to allow a plurality of wafers to be held by the support pedestal, a tray that can accommodate a plurality of wafers is used (e.g., Patent Document 1). The tray has a plurality of accommodation holes each having a diameter slightly greater than that of each wafer. A margin portion is provided so as to project from the bottom edge of the inner circumference portion of each accommodation hole toward the inner side of the accommodation hole. The margin portion holds the outer edge of the wafer from below to accommodate the wafer inside the accommodation hole. The support pedestal includes a tray placing portion where the tray is placed and a plurality of wafer holding portions provided so as to project upwardly from the tray placing portion. When the tray is placed on the tray placing portion of the support pedestal, the wafer holding portions enter the accommodation holes of the tray from below, and lift and hold the wafers at the margin portion. The wafers held by the wafer holding portions of the support pedestal are electrostatically attracted by an electrostatic attracting apparatus provided in each of the wafer holding portions. The wafers are cooled by a cooling gas (e.g., helium gas) that is supplied from a cooling gas supplying duct provided inside the support pedestal.
Patent Document 1: JP 2009-147375 A
However, with the conventional plasma processing apparatus as described above, in which a plurality of wafers are held by the support pedestal altogether by the tray having the accommodation holes penetrating through in the thickness direction, what matters is whether or not the wafers are actually accommodated in the respective accommodation holes. That is, in the case where there is any accommodation hole where no wafer is present (not accommodating the wafer) among a plurality of accommodation holes provided to the tray, the wafer holding portion corresponding to the accommodation hole with no wafer will directly be exposed to plasma. When the wafer holding portion is exposed to the plasma, not only the wafer holding portion but also the entire plasma processing apparatus may be damaged.
Accordingly, an object of the present invention is to provide a plasma processing apparatus that can prevent the wafer holding portion of the support pedestal from being directly exposed to plasma from any accommodation hole of the tray where no wafer is present.
A first mode of the present invention provides a plasma processing apparatus that includes: a conveyable stock unit for supplying and collecting a tray that accommodates a wafer in each of a plurality of accommodation holes penetrating through in a thickness direction; a processing unit that performs plasma processing to each wafer accommodated in the tray supplied from the stock unit; an alignment unit that has a table on which the tray before being subjected to the plasma processing is placed, positioning of the wafer on the table being performed at the alignment unit; and a wafer presence-absence detecting unit that detects whether or not the wafer is present in each of the accommodation holes of the tray placed on the table of the alignment unit.
Specifically, the plasma processing apparatus further includes a conveying mechanism that conveys the tray, and a conveyance control unit that causes the tray on the table to be returned to the stock unit instead of the tray being transferred to the processing unit by the conveying mechanism, when the wafer presence-absence detecting unit detects that the wafer is not accommodated in any of the accommodation holes of the tray placed on the table.
Before the plasma processing in the processing unit, the tray is placed on the table of the alignment unit for positioning. To the tray on the table, the wafer presence-absence detecting unit performs detection as to whether or not the wafer is present in each of the accommodation holes. As a result, when there is any accommodation hole where no wafer is present out of the plurality of accommodation holes provided to the tray, the tray can be prevented from being subjected to plasma processing in the processing unit.
Specifically, the wafer presence-absence detecting unit includes an optical sensor for detecting the wafer accommodated in each of the accommodation holes of the tray on the table, and a determining unit that determines whether or not the wafer is present in each of the accommodation holes provided to the tray, based on a signal from the optical sensor.
Preferably, the optical sensor includes: a light projector that projects inspection light toward the tray; and a light receiver that is arranged at a position where the inspection light is blocked and unreceived when the wafer is accommodated in any of the accommodation holes of the tray, and where the inspection light is received when the wafer is not accommodated in any of the accommodation holes of the tray.
With this structure, since presence-absence of the wafer in each of the accommodation holes is determined by whether or not the inspection light from the light projector is received by the light receiver, that is, whether or not the inspection light is blocked by the wafer, the determining unit can accurately determine whether or not the wafer is present in each of the accommodation holes.
Alternatively, the wafer presence-absence detecting unit includes: an imaging unit that images the accommodation holes of the tray on the table from above; and a determining unit that determines whether or not the wafer is present in each of the accommodation holes of the tray, based on an image obtained by the imaging unit.
The table may be a rotary table that rotates the tray within a horizontal plane. In this case, the wafer presence-absence detecting unit detects whether or not the wafer is present in each of the accommodation holes provided to the tray, while the tray is rotated by the rotary table.
With this structure, whether or not the wafer is present for each of the plurality of accommodation holes can be detected by one optical sensor whose projection direction of the inspection light is fixed, or by one imaging unit whose field of view is fixed, which is included in the wafer presence-absence detecting unit.
The alignment unit includes: a centering mechanism that performs center position alignment of the tray relative to the rotary table; and a rotary direction positioning unit that performs positioning in the rotation direction of the tray while the tray is rotated by the rotary table. The wafer presence-absence detecting unit detects whether or not the wafer is present in each of the accommodation holes provided to the tray, while the positioning in the rotation direction is performed by the rotary direction positioning unit.
With this structure, since whether or not the wafer is present in each of the accommodation holes can be detected during the positioning of the tray in the rotation direction, the time required for processing in the alignment unit can be reduced. This can contribute toward a takt time improvement of the whole plasma processing apparatus.
The plasma processing apparatus may further include an alarm issuing unit that issues an alarm when the wafer presence-absence detecting unit detects that the wafer is not accommodated in any of the accommodation holes of the tray.
The second mode of the present invention provides a plasma processing method, including: conveying from a stock unit to an alignment unit a tray that accommodates a wafer in each of a plurality of accommodation holes penetrating through in a thickness direction, and placing the tray on a table; detecting whether or not the wafer is present in each of the accommodation holes of the tray on the table of the alignment unit; conveying the tray from the alignment unit to the processing unit when the wafer is present in each of the accommodation holes of the tray on the table, and executing plasma processing; and returning the tray from the alignment unit to the stock unit when the wafer is absent in any of the accommodation holes of the tray on the table.
In the present invention, at the tray positioning stage in the alignment unit before plasma processing to the wafers is performed in the processing unit, whether or not the wafer is present in each of the accommodation holes provided to the tray is determined. As a result, when there is any accommodation hole where no wafer is present out of the plurality of accommodation holes provided to the tray, the tray can be returned to the stock unit instead of being transferred to the processing unit. Accordingly, it becomes possible to prevent the wafer holding portion of the processing unit from being directly exposed to plasma from the accommodation hole of the tray where no wafer is present. Thus, not only the wafer holding portion but also the entire plasma processing apparatus can be prevented from being damaged.
In the following, with reference to the drawings, a description will be given of an embodiment of the present invention. In
With the plasma processing apparatus 1, as shown in
As shown in
In
In
In
The conveyance arm 31 rotates within the horizontal plane by the rotation of the rotary shaft 32. Further, as being interlocked with the shifting movement of the bottom stage 33b of the horizontal shifting mechanism 33 within the horizontal plane relative to the base stage 33a, the top stage 33c shifts within the horizontal plane relative to the bottom stage 33b. This allows the conveyance arm 31 to shift within the horizontal plane.
The rotary operation of the conveyance arm 31 within the horizontal plane (the rotary operation of the rotary shaft 32) is achieved by the control apparatus 6 exerting the actuation control of the rotary shaft driving motor 32a (
In
In
The rotary table 41 rotates by the actuation of a rotary table driving motor 46 (
As shown in
The control apparatus 6 allows the conveyance arm 31 to shift in the conveyance chamber 3 within the horizontal plane, so that the conveyance arm 31 places the tray 7 on the rotary table 41. Thereafter, the control apparatus 6 exerts the actuation control of the centering mechanism driving unit 42d, so that the pair of longitudinal direction members 42a (i.e., the pair of lateral direction members 42b accordingly) are actuated to approach each other (arrow A in
After centering of the tray 7 is achieved, the control apparatus 6 exerts the actuation control of the centering mechanism driving unit 42d such that the pair of longitudinal direction members 42a (i.e., the pair of lateral direction members 42b) become away from each other. Thus, the four abutment members 42c leave the tray 7, and the tray 7 can be rotated by the rotary actuation of the rotary table 41. It is to be noted that, in the present embodiment, as shown in
In
In
The notch detecting sensor 43 can detect the position of the notch 7c of the tray 7, by observing the light reception state of the light receiver JS1 as to the inspection light L1, while the inspection light L1 is projected from the light projector HS1 in the state where the rotary table 41 on which the tray 7 is placed is rotated (arrow B in
In
The light projector HS2 of each of the wafer presence-absence detecting sensors 44A and 44B is provided at the position where the inspection light L2 can be emitted to the wafer W accommodated in the accommodation hole 7a provided to the tray 7, which is centered by the centering mechanism 42. When the inspection light L2 passes through the accommodation hole 7a of the tray 7 and the inspection light L2 is received by the light receiver JS2 (
As described above, in the present embodiment, the tray 7 accommodates one wafer W in one accommodation hole 7a arranged at its center position, and accommodates six wafers W in six accommodation holes 7a having their respective centers aligned on the phantom circle CL (the circumferential position) about the center position of the tray 7 at regular intervals. In association with this arrangement, there are the two wafer presence-absence detecting sensors, that is, the first wafer presence-absence detecting sensor 44A that performs the wafer presence-absence detection as to one accommodation hole 7a arranged at the center position of the rotary table 41, and the second wafer presence-absence detecting sensor 44B that performs the wafer presence-absence detection as to the six accommodation holes 7a arranged at the circumferential position.
Here, as shown in
The second wafer presence-absence detecting sensor 44B that performs the wafer presence-absence detection as to the six accommodation holes 7a at the circumferential position of the tray 7 is one in number. However, by allowing the tray 7 after being centered to be rotated by the rotary table 41, the single second wafer presence-absence detecting sensor 44B can perform the wafer presence-absence detection as to the six accommodation holes 7a at the circumferential position of the tray 7. It is to be noted that, the rotation control of the rotary table 41 is achieved by the wafer presence-absence determining unit 6b of the control apparatus 6 exerting the actuation control of the rotary table driving motor 46.
Further, the wafer presence-absence detection as to the six accommodation holes 7a at the circumferential position of the tray 7, performed by the single second wafer presence-absence detecting sensor 44B is executed when the tray 7 is rotated by the rotary table 41 for 7c by the notch detecting sensor 43. That is, the wafer presence-absence detection is performed in parallel with the notch detection for positioning the rotation angle position of the tray 7. Therefore, the time required for performing processing in the alignment chamber 4 can be reduced. This contributes toward the takt time improvement of the whole plasma processing apparatus 1.
Further, as described above, with the plasma processing apparatus 1 according to the present embodiment, the second wafer presence-absence detecting sensor 44B emits the inspection light L2 to the region that is outside the outer edge of the rotary table 41 and that is inner than the phantom circle SS inscribed to the six accommodation holes 7a arranged at the circumferential position of the tray 7. Therefore, even in the case where no wafer W is present in the accommodation hole 7a, which is the detection target, of the tray 7, the inspection light L2 will not be reflected by the rotary table 41. Accordingly, the wafer presence-absence determining unit 6b of the control apparatus 6 can be prevented from erroneously recognizing that the wafer W is present as to the accommodation hole 7a in which no wafer W is present.
In
In
In
In
Next, a description will be given of the procedure in which the plurality of wafers W are subjected to plasma processing by a batch process by the plasma processing apparatus 1. The control apparatus 6 firstly shifts the conveyance arm 31, and allows the conveyance arm 31 to hold one of a plurality of the trays 7 (the wafer W is accommodated in each of the accommodation holes 7a of each of the trays 7) supplied to the stock unit 2. Thereafter, the control apparatus 6 actuates the conveyance arm 31 to shift the tray 7 in the alignment chamber 4 (arrow D1 in
The control apparatus 6 places the tray 7 on the rotary table 41 of the alignment chamber 4 in the foregoing manner, and thereafter exerts the actuation control of the centering mechanism driving unit 42d to actuate the centering mechanism 42, to perform centering of the tray 7 in the manner described in the foregoing (Step ST1 in
Further, the control apparatus 6 executes the wafer presence-absence detection in parallel with the detection of the notch 7c performed by the notch detecting sensor 43. That is, when the rotary table 41 is actuated to rotate the tray 7 for detection of the notch 7c and the tray 7 is rotated, the two wafer presence-absence detecting sensors (the first wafer presence-absence detecting sensor 44A and the second wafer presence-absence detecting sensor 44B) perform the wafer presence-absence detection as to each of the accommodation holes 7a of the tray 7 (Step ST2 in
After Step ST2 is finished, the control apparatus 6 determines whether or not detection of the notch 7c has succeeded (Step ST3 in
On the other hand, when the wafer presence-absence determining unit 6b of the control apparatus 6 determines that the notch 7c is successfully detected in Step ST3, the control apparatus 6 determines that whether or not the wafer W is present in every accommodation hole 7a provided to the tray 7, based on the result of Step ST2 (Step ST5 in
In Step ST5, when the wafer presence-absence determining unit 6b does not determine that the wafer W is present in every accommodation hole 7a provided to the tray 7, that is, when the wafer presence-absence determining unit 6b determines that there is any accommodation hole 7a in which no wafer W is present among the seven accommodation holes 7a provided to the tray 7 (no wafer), an error message (alert) is displayed on the display unit 61 (Step ST4 in
Further, when it is determined that there is any accommodation hole 7a in which no wafer W is present among the seven accommodation holes 7a provided to the tray 7 (no wafer), the control apparatus 6 enters the standby state for returning the tray 7 to the stock unit 2 (Step ST4 in
On the other hand, when the wafer presence-absence determining unit 6b determines that a wafer W is present in every accommodation hole 7a provided to the tray 7 in Step ST5 (wafer present), the control apparatus 6 rotates the rotary table 41, to perform the positioning in the rotation direction of the tray 7 based on the position of the notch 7c detected in Step ST2 (Step ST6 in
When the wafer presence-absence determining unit 6b determines that no wafer W is present in any of the accommodation holes 7a (no wafer) and the standby state in Step ST4 is entered, the control apparatus 6 actuates the conveyance arm 31 and returns the tray 7 on the rotary table 41 to the stock unit 2.
In this manner, with the plasma processing apparatus 1 according to the present embodiment, at the stage before the plasma processing is performed to the wafers W where the tray 7 is held by the rotary table 41, detection as to whether or not the wafer W is present in each of the accommodation holes 7a provided to the tray 7 (the wafer presence-absence detection) is performed. As a result, in the case where there is any accommodation hole 7a in which no wafer W is present among the plurality of accommodation holes 7a, the tray 7 is not conveyed to the processing chamber 5.
When the wafer presence-absence determining unit 6b determines that the wafer W is present in every accommodation hole 7a and the standby state in Step ST7 is entered, the control apparatus 6 actuates the conveyance arm 31 so as to hold the tray 7 on the rotary table 41, and to place the tray 7 on the susceptor 51 of the processing chamber 5 via the conveyance chamber 3. This operation is represented by arrow E1 in
When the control apparatus 6 allows the tray 7 to be held by the four up-and-down pins 54, the control apparatus 6 allows the conveyance arm 31 to recede from the processing chamber 5 (arrow E3 in
After the control apparatus 6 establishes the sealed state of the processing chamber 5, the control apparatus 6 exerts the actuation control of the up-and-down pin driving mechanism 53 so as to lower the four up-and-down pins 54. This lowering allows the tray 7 to be placed on the tray placing portion 51a of the susceptor 51, and the wafers W accommodated in the accommodation holes 7a of the tray 7 to be placed on (held by) the wafer holding portions 51b of the susceptor 51 (
After the control apparatus 6 allows the tray 7 and the wafers W to be placed on the susceptor 51, the control apparatus 6 performs the actuation control of the gas supplying source 52a so as to supply gas for generating plasma in the processing chamber 5. Next, the DC voltage applying apparatus 52d is actuated so as to apply a DC voltage to the electrostatic attraction-purpose electrodes 56 in the wafer holding portions 51b. Thus, the wafers W on the wafer holding portions 51b are electrostatically attracted to the electrostatic attraction-purpose electrodes 56.
When the control apparatus 6 senses that the gas for generating plasma supplied into the processing chamber 5 is adjusted to a predetermined pressure, the control apparatus 6 exerts the actuation control of the first high-frequency voltage applying apparatus 52c so as to apply a high-frequency voltage to the induction coil 55. Thus, plasma is generated inside the processing chamber 5.
After the wafers W are held on the wafer holding portions 51b by the electrostatic attraction, the control apparatus 6 actuates the cooling gas supplying apparatus 52f such that the bottom face of the wafer holding portions 51b is filled with the cooling gas from the cooling gas supplying duct 58. Further, the control apparatus 6 exerts the actuation control of the second high-frequency voltage applying apparatus 52g, so that the plasma in the processing chamber 5 is attracted to the wafers W on the wafer holding portions 51b. Thus, the wafer processing (etching) to the wafers W is started.
When a predetermined time has elapsed from the start of the plasma processing to the wafers W, the control apparatus 6 stops the application of the bias voltage to the electrostatic attraction-purpose electrodes 56 by the second high-frequency voltage applying apparatus 52g, to thereby stop plasma generation in the processing chamber 5. Next, the control apparatus 6 exerts the actuation control of the cooling gas supplying apparatus 52f so as to stop supply of the cooling gas. After the cooling gas supply has stopped, at the timing where the pressure of the cooling gas at the bottom face of the wafer W has fully reduced, the control apparatus 6 stops supply of the gas from the gas supplying source 52a to the processing chamber 5, and stops application of the high-frequency voltage to the induction coil 55 by the first high-frequency voltage applying apparatus 52c. Further, the control apparatus 6 stops application of the DC voltage to the electrostatic attraction-purpose electrodes 56 by the DC voltage applying apparatus 52d, to thereby release the electrostatic attraction of the wafers W. After the wafer electrostatic attraction is released, diselectrification is performed as necessary to eliminate electrostatics remaining on the wafers W or the tray 7, and processing in the processing unit ends.
During the processing in the processing chamber 5 described above, the control apparatus 6 constantly causes the vacuum evacuating apparatus 52b to perform the evacuation operation of the gas in the processing chamber 5 to the outside of the plasma processing apparatus 1, and causes the coolant circulating apparatus 52e to perform the circulation operation of coolant into the coolant flow channel 57. By the coolant circulating apparatus 52e performing the coolant circulation operation in the coolant flow channel 57, the wafers W are cooled via the susceptor 51. Thus, high plasma processing efficiency can be retained in synergy with the cooling of the wafers W through the cooling gas.
It is to be noted that, as described above, during the plasma processing to the wafers W in the processing chamber 5, the control apparatus 6 actuates the conveyance arm 31, so as to take out the tray 7 accommodating the wafers W to be subjected to plasma processing next from the stock unit 2, and to convey the tray 7 to the alignment chamber 4. Further, the control apparatus 6 allows the tray 7 to be placed on the rotary table 41. Thus, during execution of the plasma processing to the wafers W in the processing chamber 5, the center position alignment (centering), the positioning in the rotation direction of the rotary table 41, and the presence-absence detection of the wafers W can be performed as to the tray 7 accommodating the wafers W to be subjected to the plasma processing next.
When the plasma processing to the wafers W in the processing chamber 5 is finished, the control apparatus 6 actuates the up-and-down pin driving mechanism 53 to raise the four up-and-down pins 54, so that the tray 7 is lifted and held above the susceptor 51. It is to be noted that, the four up-and-down pins 54 fit in the up-and-down pin fitting holes 7d provided on the bottom face side of the tray 7 from below in the process of raising.
When the tray 7 is lifted and held above the susceptor 51 by the raising actuation of the up-and-down pins 54, the control apparatus 6 opens the gate valve 8 to allow the conveyance arm 31 to enter the processing chamber 5. Further, the control apparatus 6 allows the tray 7 being lifted and held by the up-and-down pins 54 to be retained by the conveyance arm 31, and to leave the processing chamber 5. Then, the control apparatus 6 allows the tray 5 to be placed on the tray temporarily placement table 45 of the alignment chamber 4 (arrows F1 and F2 in
In this manner, the tray 7 conveyed from the processing chamber 5 is temporarily placed on the tray temporarily placement table 45, and is returned to the stock unit 2 after being cooled. Thus, the wafers W (tray 7) are prevented from being returned to the stock unit 2 in the state where the wafers W are kept at high temperatures by the plasma processing. Further, in the state where the tray 7 accommodating the wafers W at high temperatures is still placed on the tray temporarily placement table 45, the tray 7 accommodating the wafers W to be subjected to the plasma processing next is taken out from the alignment chamber 4 and conveyed to the processing chamber 5. Thus, the time required for the whole plasma processing can be shortened and the work can efficiently be performed.
When the tray 7 placed on the tray temporarily placement table 45 is returned to the stock unit 2, the batch process for the wafers W accommodated in the tray 7 ends.
As described in the foregoing, the plasma processing apparatus 1 in the present embodiment includes: the alignment chamber 4 where the positioning of the tray 7 accommodating the wafer W in each of the plurality of (seven herein) accommodation holes 7a; and the processing chamber 5 where the plasma processing is performed to the wafer W accommodated in each of the plurality of accommodation holes 7a of the tray 7. Further, the plasma processing apparatus 1 includes: the rotary table 41 that holds the tray 7 accommodating the wafers W and rotates the tray 7 within the horizontal plane in the alignment chamber 4; the centering mechanism 42 that performs the center position alignment of the tray 7 relative to the rotary table 41 in the alignment chamber 4; and rotation direction positioning means (the notch detecting sensor 43 and the alignment processing unit 6a of the control apparatus 6) for performing positioning in the rotation direction of the tray 7 while the tray 7 is rotated by the rotary table 41 in the alignment chamber 4. Further, the plasma processing apparatus 1 includes: the susceptor 51 (the support pedestal) provided with the tray placing portion 51a on which the tray 7 is placed in the processing chamber 5 and the plurality of wafer holding portions 51b that lift and hold the wafers W by entering the accommodation holes 7a of the tray 7 from below when the tray 7 is placed on the tray placing portion 51a; and the plasma processing unit 52 (the plasma processing means) that performs the plasma processing to the plurality of wafers W held by the plurality of wafer holding portions 51b provided to the susceptor 51. Still further, the plasma processing apparatus 1 includes: the conveyance arm 31 as conveying means for conveying the tray 7 having undergone the center position alignment relative to the rotary table 41 by the centering mechanism 42 and the positioning in the rotation direction by the rotation direction positioning means from the rotary table 41 of the alignment chamber 4 to the susceptor 51 in the processing chamber 5; the two wafer presence-absence detecting sensors 44A and 44B as the wafer presence-absence detecting unit that perform detection as to whether or not the wafer W is present in each of the accommodation holes 7a of the tray 7 held by the rotary table 41 of the alignment chamber 4 (the wafer presence-absence detection); and the wafer presence-absence determining unit 6b of the control apparatus 6.
The plasma processing apparatus 1 according to the present embodiment is structured such that, at the stage of positioning the tray 7 in the alignment chamber 4 before the plasma processing to the wafers W in the processing chamber 5 is performed (i.e., at the stage of centering and positioning in the rotation direction of the tray 7), the detection as to whether or not the wafer W is present in each of the accommodation holes 7a provided to the tray 7 is performed (the wafer presence-absence detection). As a result, in the case where there is any accommodation hole 7a in which no wafer W is present out of the plurality of accommodation holes 7a provided to the tray 7, the tray 7 can be prevented from being placed on the susceptor 51. Thus, it becomes possible to prevent the wafer holding portion 51b from being directly exposed to plasma from the accommodation hole 7a of the tray 7 where no wafer W is present, and hence to prevent not only the wafer holding portion 51b but also the entire plasma processing apparatus 1 from being damaged.
Further, in the plasma processing apparatus 1 according to the present embodiment, the wafer presence-absence determining unit 6b performs detection as to whether or not the wafer W is present in each accommodation hole 7a based on whether or not the inspection light L2 emitted from the wafer presence-absence detecting sensors 44A and 44B to the wafer W accommodated in the tray 7 held by the rotary table 41 is detected. In this manner, since the presence-absence of the wafer W in each accommodation hole 7a is determined based on whether or not the inspection light L2 is blocked by the wafer W, despite its simple structure, the wafer presence-absence determining unit 6b can accurately determine presence or absence of the wafer W in each accommodation hole 7a.
Further, in the plasma processing apparatus 1 according to the present embodiment, the wafer presence-absence detecting unit performs the wafer presence-absence detection while the tray 7 is rotated by the rotary table 41. Thus, the time required for detecting presence or absence of the wafer can be reduced, and the processing work time in the plasma processing apparatus 1 can be reduced.
In the foregoing, though the description has been given of the embodiment of the present invention, the present invention is not limited to the embodiment described above. For example, in the embodiment described above, the tray 7 is structured to accommodate one wafer W in one accommodation hole 7a arranged at the center position, and six wafers W in six accommodation holes 7a having their respective centers disposed at regular intervals on the phantom circle CL about the center position. However, this is merely one example, and the number of wafers W that can be accommodated in the tray 7 or disposition of the accommodation holes 7a can arbitrarily be set.
Further, in the present embodiment, the notch detecting sensor 43 can detect the notch 7c that is formed by cutting out part of the outer edge of the tray 7. The wafer presence-absence detecting means 44A and 44B are only required to be capable of detecting whether or not the wafer W is present in each accommodation hole 7a provided to the tray 7. Accordingly, the sensors 43, 44A, and 44B may not necessarily be the transmission type optical sensors described above, and may each be other sensor such as a reflection type optical sensor (i.e., an optical sensor that is provided with a light projecting unit and a light receiving unit that receives the reflection light of the inspection light projected by the light projecting unit, the light projecting unit and the light receiving unit being provided in an integrated manner). It is to be noted that, in the case where the reflection type optical sensors are used, the light projectors HS1 and HS2 shown in
In the embodiment described above, the transmission type optical sensors (the wafer presence-absence detecting sensors 44A and 44B) are used as the wafer presence-absence detecting means that detect whether or not the wafer W is present in each of the accommodation holes 7a provided to the tray 7 held by the rotary table 41. However, in place of such optical sensors, an imaging apparatus such as a CCD camera may be used, so that the wafer presence-absence detection may be performed based on an image obtained by imaging the tray 7 on the rotary table 41 from above by the imaging apparatus. In this case, the wafer presence-absence determining unit 6b determines whether or not the wafer W is present in each accommodation hole 7a based on the image imaged by the imaging apparatus. While the tray 7 is rotated by the rotary table 41, by the imaging apparatus such as a CCD camera performing imaging, it becomes possible to detect whether or not the wafer is present in each of the plurality of accommodation holes 7a with one imaging apparatus whose field of view is fixed.
In the embodiment, the mechanism for aligning the tray 7 including the rotary table 41 is disposed in the independent alignment chamber 4. However, the mechanism for aligning the tray 7 including the rotary table 41 may be disposed in the conveyance chamber 3. The present invention is also applicable to this structure.
The specific structure related to the stock unit 2 is not limited to the one shown in the embodiment. For example, the plasma processing apparatus 1 according to a modified embodiment shown in
The transfer robot 83 performs, as conceptually indicated by arrow G1 in
What is provided is a plasma processing apparatus that can prevent the wafer holding portion of the support pedestal from being directly exposed to the plasma from the accommodation hole of the tray where no wafer is present.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-121094 | May 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/002908 | 5/25/2011 | WO | 00 | 11/26/2012 |
