One aspect of the present invention relates to an inspection device and an inspection method.
In order to cut a wafer including a semiconductor substrate and a functional element layer formed on one surface of the semiconductor substrate along each of a plurality of lines, an inspection device that forms a plurality of rows of modified regions inside the semiconductor substrate along each of the plurality of lines by irradiating the wafer with a laser beam from the other surface side of the semiconductor substrate is known. An inspection device described in Patent Literature 1 includes an infrared camera and can observe a modified region formed inside a semiconductor substrate, processing damage formed on the functional element layer, and the like from the back surface side of the semiconductor substrate.
[Patent Literature 1] Japanese Unexamined Patent Publication No. 2017-64746
In the inspection device as described above, in the stage before the wafer is irradiated with the laser beam (the wafer is laser-processed), it is necessary to determine processing condition including irradiation conditions of the laser beam based on wafer information, a laser processing target, and the like. In order to appropriately determine the processing condition, for example, it is necessary for a user to repeatedly perform the laser processing process while adjusting the processing condition to derive the appropriate processing condition.
One aspect of the present invention has been made in view of the above circumstances, and an object of the present invention is to provide an inspection device and an inspection method capable of easily determining appropriate processing condition.
An inspection device according to one aspect of the present invention includes an irradiation part configured to irradiate a wafer with a laser beam, an imaging part configured to take an image of the wafer, an input part configured to receive an input of information, and a control part, wherein the input part receives an input of wafer processing information including information of the wafer and a laser processing target for the wafer, and the control part is configured to determine a processing condition including an irradiation condition of the laser beam by the irradiation part based on the wafer processing information received by the input part, to control the irradiation part so that the wafer is irradiated with the laser beam according to the determined processing condition, to acquire a laser processing result of the wafer due to the irradiation of the laser beam by controlling the imaging part to take an image of the wafer, and to evaluate the processing condition based on the laser processing result.
In the inspection device according to the aspect of the present invention, when the wafer processing information is input, the processing condition corresponding to the wafer processing information is determined. In this way, since the processing condition is automatically determined by inputting the wafer processing information, for example, the processing condition can be easily determined as compared with a case in which the laser processing process is repeatedly performed while the user adjusts the processing condition to derive an appropriate processing condition. Then, the inspection device according to the aspect of the present invention evaluates the processing condition based on the laser processing result performed in the determined processing condition. Thus, for example, the processing condition can be appropriately optimized by changing the processing condition as necessary based on the evaluation result. As described above, according to the inspection device according to the aspect of the present invention, the appropriate processing condition can be easily determined.
The control part may determine the processing condition corresponding to the wafer processing information received through the input part by referring to a database in which the wafer processing information and the processing condition are stored in association with each other. The processing condition determination process can be simplified by determining the processing condition based on the information in the database.
The control part may evaluate the processing condition based on the laser processing result and the wafer processing information. Thus, for example, the processing condition can be evaluated based on whether or not the actual laser processing has been performed so that the laser processing target for the wafer is achieved, and the processing condition can be appropriately evaluated.
The control part may be configured to further correct the processing condition based on the laser processing result when it is evaluated that the processing condition is not appropriate. Thus, when the processing condition is not appropriate, the processing condition can be automatically changed based on the laser processing result, and the processing condition can be optimized more easily.
When the processing condition is corrected, the control part may configured to further update the database based on information including the corrected processing condition. When the processing condition is determined later based on the input of the wafer processing information, it becomes possible to determine a more appropriate processing condition by registering the corrected processing condition in the database in this way.
The above-described inspection device may further include a display part configured to display information, and the control part may be configured to further control the display part so that the determined processing condition is displayed. Due to the processing condition (suggested to the user) being displayed, it is possible to inform the user a kind of processing condition with which the processing is performed, and it is possible to change the processing condition based on a user's instruction or the like as needed.
The control part may extract a plurality of processing condition candidates that are processing condition candidates corresponding to the wafer processing information that has received the input by referring to the database and may control the display part so that the plurality of processing condition candidates are displayed. Thus, when there are a plurality of (suitable) processing conditions corresponding to the processing information of the wafer, each of the processing condition candidates can be displayed (suggested to the user) as a processing condition candidate.
The input part may receive a user input for selecting one processing condition candidate in a state in which the plurality of processing condition candidates are displayed by the display part, and the control part may determine the processing condition candidate selected in the user input received through the input part as the processing condition. Thus, the processing condition desired by the user can be determined from the plurality of processing condition candidates based on the user's instruction.
The control part may derive a degree of matching with the wafer processing information for each of the plurality of processing condition candidates and may control the display part so that the plurality of processing condition candidates are displayed in a display mode in consideration of the degree of matching. Thus, for example, it is possible to show the user the degree of matching, and to distinguish between the processing condition candidates with a high degree of matching and the processing condition candidates with a low degree of matching and to display them, and it is possible to make it easier for the user to select an appropriate processing condition from the plurality of processing condition candidates.
The control part may derive an estimation processing result when the wafer is irradiated with the laser beam by the irradiation part based on the processing condition and may control the display part so that an estimation processing result image that is an image of the estimation processing result is displayed. It is possible to show validity of the processing condition to the user and make it easier for the user to determine whether or not the processing condition needs to be changed by displaying a processing image when the laser processing is performed based on the processing condition.
The input part may receive an input of first correction information related to correction of a processing position in the estimation processing result image in a state in which the estimation processing result image is displayed by the display part, and the control part may correct the estimation processing result based on the first correction information and corrects the processing condition so that the corrected estimation processing result is obtained. Thus, the processing condition can be easily corrected based on a correction instruction of the estimation processing result image from the user who has confirmed the estimation processing result image. For the user, when the correction instruction of the estimation processing result image is issued to obtain a desired processing result, the processing condition is automatically corrected according to the correction instruction, and thus the desired processing can be easily performed.
The input part may receive an input of second correction information related to correction of the processing condition in a state in which the processing condition is displayed by the display part, and the control part may correct the processing condition based on the second correction information and corrects the estimation processing result based on the corrected processing condition. Thus, the processing condition can be easily corrected based on the correction instruction from the user, and the estimation processing result image when the processing condition is the corrected one can be appropriately displayed.
The control part may control the display part so that the laser processing result is displayed. Thus, the laser processing result according to the processing condition can be shown to the user.
The control part may control the display part so that a message that prompts correction is displayed when the wafer processing information received through the input part is not appropriate. Thus, it is possible to prompt the user to make the correction when inappropriate wafer processing information is input.
The wafer processing information may include information that indicates a finish thickness of the wafer. Thus, for example, the processing condition can be appropriately determined in consideration of the finish thickness of the wafer when grinding is performed after stealth dicing.
The wafer processing information may include crack reach information that indicates whether a crack extending from a modified region formed when the wafer is irradiated with the laser beam reaches or does not reach a surface of the wafer, and information that indicates an expected extension amount of the crack due to grinding after the irradiation of the laser beam when the crack reach information indicates that the crack do not reach the surface of the wafer. Thus, for example, when the crack reaches the surface of the wafer by performing grinding after stealth dicing to cause the crack to extend, the processing condition can be determined by appropriately considering an extension amount of the crack due to the grinding.
The wafer processing information may include finish cross section information that indicates whether or not a modified region formed when the wafer is irradiated with the laser beam appears on the finish cross section of the wafer after the laser processing and grinding processing are completed. Thus, for example, when the user desires not to leave the modified region on the finish cross section for the purpose of increasing strength of a chip or reducing particles, the processing condition can be determined by appropriately considering information of such a finish cross section.
An inspection device according to another aspect of the present invention includes an irradiation part configured to irradiate a wafer with a laser beam, an input part configured to receive an input of information, and a control part, wherein the input part receives an input of wafer processing information including information of the wafer and a laser processing target for the wafer, and the control part is configured to derive an estimation processing result when the wafer is irradiated with the laser beam by the irradiation part based on the wafer processing information received by the input part, and to determine a processing condition including an irradiation condition of the laser beam by the irradiation part based on the estimation processing result.
In the inspection device according to the aspect of the present invention, when the wafer processing information is input, the estimation processing result corresponding to the wafer processing information is derived, and the processing condition is determined based on the estimation processing result. In this way, since the processing condition is automatically determined by inputting the wafer processing information, the processing condition can be easily determined, for example, as compared with a case in which the laser processing process is repeatedly performed while the user adjusts the processing condition to derive an appropriate processing condition. As described above, according to the inspection device according to the aspect of the present invention, the processing condition can be easily and appropriately determined.
An inspection method according to yet another aspect of the present invention includes a first step of receiving an input of wafer processing information including information of a wafer and a laser processing target for the wafer, a second step of determining a processing condition including an irradiation condition of a laser beam radiated to the wafer based on the wafer processing information received in the first step, a third step of irradiating the wafer with the laser beam based on the processing condition determined in the second step, and a fourth step of evaluating the processing condition based on a laser processing result of the wafer by the irradiation of the laser beam in the third step.
An inspection method according to still another aspect of the present invention includes a first step of receiving an input of wafer processing information including information of a wafer and a laser processing target for the wafer, a second step of deriving an estimation processing result when the wafer is irradiated with a laser beam based on the wafer processing information received in the first step, and a third step of determining a processing condition including an irradiation condition of the laser beam based on the estimation processing result derived in the second step.
According to the inspection device and the inspection method according to one aspect of the present invention, it is possible to easily determine appropriate processing condition.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each of the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate description thereof will be omitted.
[Configuration of Inspection Device]
As shown in
The stage 2 supports the target object 11 by, for example, adsorbing a film attached to the target object 11. The stage 2 can move along each of an X direction and a Y direction and can rotate around an axis parallel to a Z direction as a center line. The X and Y directions are a first horizontal direction and a second horizontal direction that are perpendicular to each other, and the Z direction is a vertical direction.
The laser irradiation unit 3 concentrates the laser beam L having permeability with respect to the target object 11 and irradiates the target object 11. When the laser beam L is concentrated inside the target object 11 supported by the stage 2, the laser beam L is particularly absorbed at a portion corresponding to a condensing point C of the laser beam L, and the modified region 12 is formed inside the target object 11.
The modified region 12 is a region in which density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding non-modified region. The modified region 12 includes, for example, a melt processing region, a crack region, an insulation breakdown region, a refractive index change region, and the like. The modified region 12 has characteristics that a crack easily extends from the modified region 12 to the incident side of the laser beam L and the opposite side thereto. Such characteristics of the modified region 12 are utilized for cutting the target object 11.
As an example, when the stage 2 is moved in the X direction and the condensing point C is moved relative to the target object 11 in the X direction, a plurality of modified spots 12s are formed to be arranged in one row in the X direction. One modified spot 12s is formed by irradiation with one pulse of the laser beam L. The modified region 12 in one row is a set of a plurality of modified spots 12s arranged in one row. Adjacent modified spots 12s may be connected to each other or separated from each other according to a relative moving speed of the condensing point C with respect to the target object 11 and a repetition frequency of the laser beam L.
The imaging unit 4 takes an image of the modified region 12 formed in the target object 11 and a tip end of a crack that extends from the modified region 12.
Under control of the control part 8, the imaging unit 5 and the imaging unit 6 take an image of the target object 11 supported by the stage 2 by light transmitted through the target object 11. The image obtained by the imaging units 5 and 6 is, as an example, used for alignment of an irradiation position of the laser beam L.
The drive unit 7 supports the laser irradiation unit 3 and the plurality of imaging units 4, 5, and 6. The drive unit 7 moves the laser irradiation unit 3 and the plurality of imaging units 4, 5, and 6 in the Z direction.
The control part 8 controls operations of the stage 2, the laser irradiation unit 3, the plurality of imaging units 4, 5, and 6, and the drive unit 7. The control part 8 is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the control part 8, the processor executes software (a program) read into the memory or the like, and reading and writing of data in the memory and storage, and communication by the communication device are controlled.
The display 150 has a function as an input part for receiving an input of information from a user and a function as a display part for displaying information to the user.
[Configuration of Target Object]
The target object 11 of the present embodiment is a wafer 20 as shown in
The wafer 20 is cut along each of a plurality of lines 15 for each of the functional elements 22a. The plurality of lines 15 pass between the plurality of functional elements 22a when seen in a thickness direction of the wafer 20. More specifically, the line 15 passes through a center of a street region 23 (a center in a width direction) when seen from the thickness direction of the wafer 20. The street region 23 extends to pass between adjacent functional elements 22a in the functional element layer 22. In the present embodiment, the plurality of functional elements 22a are arranged in a matrix along the front surface 21a, and the plurality of lines 15 are set in a grid pattern. The line 15 is a virtual line here, but may be a line actually drawn.
[Configuration of Laser Irradiation Unit]
As shown in
In the present embodiment, the laser irradiation unit 3 forms two rows of modified regions 12a and 12b inside the semiconductor substrate 21 along each of the plurality of lines 15 by irradiating the wafer 20 with the laser beam L from the back surface 21b side of the semiconductor substrate 21 along each of the plurality of lines 15. The modified region 12a is a modified region closest to the front surface 21a in the two rows of modified regions 12a and 12b. The modified region 12b is a modified region closest to the modified region 12a in the two rows of modified regions 12a and 12b and is a modified region closest to the back surface 21b.
The two rows of modified regions 12a and 12b are adjacent to each other in the thickness direction (the Z direction) of the wafer 20. The two rows of modified regions 12a and 12b are formed by moving two condensing points C1 and C2 relative to the semiconductor substrate 21 along the line 15. The laser beam L is modulated by the spatial light modulator 32 so that, for example, the condensing point C2 is located on the back side in a traveling direction and on the incident side of the laser beam L with respect to the condensing point C1. Regarding formation of the modified region, it may be of single focus or multifocal, and may be of one pass or multiple passes.
The laser irradiation unit 3 irradiates the wafer 20 with the laser beam L from the back surface 21b side of the semiconductor substrate 21 along each of the plurality of lines 15. As an example, for the semiconductor substrate 21 which is a single crystal silicon substrate having a thickness of 775 μm, the two condensing points C1 and C2 are respectively focused at a position of 54 μm and a position of 128 μm from the front surface 21a, and the wafer 20 is irradiated with the laser beam L from the back surface 21b side of the semiconductor substrate 21 along each of the plurality of lines 15. At this time, for example, when a condition is that a crack 14 that extends over the two rows of modified regions 12a and 12b reaches the front surface 21a of the semiconductor substrate 21, a wavelength of the laser beam L is 1099 nm, a pulse width is 700 nsec, and a repetition frequency is 120 kHz. Further, an output of the laser beam L at the condensing point C1 is 2.7 W, an output of the laser beam L at the condensing point C2 is 2.7 W, and a relative moving speed of the two condensing points C1 and C2 with respect to the semiconductor substrate 21 is 800 mm/sec.
The formation of the two rows of modified regions 12a and 12b and the crack 14 is carried out in the following case. That is, this is a case in which, in a later step, for example, the semiconductor substrate 21 is thinned by grinding the back surface 21b of the semiconductor substrate 21, the crack 14 is exposed on the back surface 21b, and the wafer 20 is cut into a plurality of semiconductor devices along each of the plurality of lines 15.
[Configuration of Inspection Imaging Unit]
As shown in
The objective lens 43 passes the light I1 reflected by the front surface 21a of the semiconductor substrate 21. That is, the objective lens 43 passes the light I1 propagating through the semiconductor substrate 21. A numerical aperture (NA) of the objective lens 43 is, for example, 0.45 or more. The objective lens 43 has a correction ring 43a. The correction ring 43a corrects aberration generated in the light I1 in the semiconductor substrate 21 by adjusting a distance between a plurality of lenses constituting the objective lens 43, for example. A means for correcting the aberration is not limited to the correction ring 43a and may be another correction means such as a spatial light modulator. The light detection part 44 detects the light I1 that has passed through the objective lens 43 and the mirror 42. The light detection part 44 is configured of, for example, an InGaAs camera and detects the light I1 in the near infrared region. A means for detecting (imaging) the light I1 in the near infrared region is not limited to the InGaAs camera, and other imaging means may be used as long as it performs transmission type imaging such as a transmission type confocal microscope.
The imaging unit 4 can image the two rows of modified regions 12a and 12b and tip ends of a plurality of cracks 14a, 14b, 14c and 14d (details will be described below). The crack 14a is a crack that extends from the modified region 12a toward the front surface 21a. The crack 14b is a crack that extends from the modified region 12a to the back surface 21b side. The crack 14c is a crack that extends from the modified region 12b toward the front surface 21a. The crack 14d is a crack that extends from the modified region 12b to the back surface 21b side.
[Configuration of Imaging Unit for Alignment Correction]
As shown in
The lens 53 passes the light I2 reflected by the front surface 21a of the semiconductor substrate 21. That is, the lens 53 passes the light I2 propagating through the semiconductor substrate 21. A numerical aperture of the lens 53 is 0.3 or less. That is, the numerical aperture of the objective lens 43 of the imaging unit 4 is larger than the numerical aperture of the lens 53. The light detection part 54 detects the light I2 that has passed through the lens 53 and the mirror 52. The light detection part 55 is configured of, for example, an InGaAs camera and detects the light I2 in the near infrared region.
Under the control of the control part 8, the imaging unit 5 takes an image of the functional element layer 22 by irradiating the wafer 20 with the light I2 from the back surface 21b side and detecting the light I2 returning from the front surface 21a (the functional element layer 22). Further, similarly, under the control of the control part 8, the imaging unit 5 acquires an image of a region including the modified regions 12a and 12b by irradiating the wafer 20 with the light I2 from the back surface 21b side and detecting the light I2 returning from formation positions of the modified regions 12a and 12b in the semiconductor substrate 21. The images are used for alignment of an irradiation position of the laser beam L. The imaging unit 6 has the same configuration as the imaging unit 5 except that the lens 53 has a lower magnification (for example, 6 times in the imaging unit 5 and 1.5 times in the imaging unit 6) than the lens 53, and is used for alignment as in the imaging unit 5.
[Imaging Principle of Inspection Imaging Unit]
As shown in
As shown in
It is presumed that the reason why the crack 14 itself cannot be confirmed as described above is that a width of the crack 14 is smaller than a wavelength of the light I1 which is illumination light.
The imaging principle assumed based on the above is as follows. As shown in
As shown in
[Processing Condition Derivation Process]
Hereinafter, a processing condition derivation process which is performed as a pretreatment for a process of forming the modified region for the purpose of cutting the wafer 20 will be described. The processing condition is a recipe related to processing that indicates conditions and procedures for processing the wafer 20. The control part 8 is configured to determine the processing condition including irradiation condition of a laser beam by the laser irradiation unit 3 based on information received by the display 150 (a processing condition determination process), to control the laser irradiation unit 3 so that the wafer 20 is irradiated with the laser beam under the determined processing condition (a processing process), to acquire a laser processing result of the wafer 20 due to the irradiation of the laser beam by controlling the imaging unit 4 to take an image of the wafer 20 (a processing result acquisition process), and to evaluate the processing condition based on the laser processing result (a processing condition evaluation process).
(Processing Condition Determination Process)
The processing condition determination process will be described with reference to
As shown in
As shown in
The wafer type is, for example, a type such as a “0°” product or a “45°” product according to a position of the notch. For example, when 45° is set as the wafer type, bottom side half-cut (BHC) is recommended in a BHC state of processing setting which will be described below. The “BHC” is a term indicating a state in which the crack 14 reaches the front surface 21a (that is, a crack reaching state). In order to be BHC, it is sufficient that the crack 14 reaches the front surface 21a, and it does not matter whether or not the crack 14 reaches a pattern surface (a surface of the functional element layer 22). When 0° is set as the wafer type, both stealth (ST) and BHC are recommended in the BHC state of the processing setting which will be described below. The “ST” is a term indicating a state in which the crack 14 does not reach the back surface 21b and the front surface 21a. A state of the incident surface is information that indicates a film type (a refractive index), a film thickness, and the like of the incident surface. A reflectance is calculated by the control part 8 based on the state of the incident surface, the laser wavelength, and the like, and the output of the laser beam is determined. The resistance value (the doping amount) is a value of resistance (in the case of the doping amount, a value obtained by converting the doping amount into the resistance value). An arrival rate is calculated by the control part 8 based on the resistance value, the laser wavelength, and the like, and the output of the laser beam is determined. The Index size is information used for determining an index value of a dicer and the like. When an unknown wafer 20 is processed, the wafer type, the state of the incident surface, the resistance value, and the like are unknown and may not be set.
As shown in
The number of passes is information that indicates the number of passes and the number of focal points. The number of passes is set to a value desired by the user. In a case in which the processing is not possible with the set number of passes, the control part 8 may increase the number of passes when the processing condition (the recipe) is proposed to the user or when the processing condition (the recipe) is corrected. When the variety of wafer processing information received through the display 150 is not appropriate, the control part 8 may control the display 150 so that a message that prompts correction is displayed. The speed is a laser processing speed. The control part 8 determines a laser output, a frequency, and a pulse pitch in consideration of the set speed. When the processing is not possible at the set speed, the control part 8 may change the speed when the processing condition (the recipe) is proposed to the user or when the processing condition (the recipe) is corrected. The splash range is information that indicates a width of the splash. When the splash range is narrow, the control part 8 may determine the Z height or pulse pitch in the ST state, or may determine the processing condition in which a black streak is generated.
The finish cross section is information that indicates whether or not the modified region (a stealth dicing (SD) layer) formed when the wafer 20 is irradiated with the laser beam appears on a chip cross section (a finish cross section of the wafer 20) after a laser processing and a finishing (grinding) processing are completed. In the SDBG, since the grinding is performed after the laser processing, it is possible to finish without leaving the SD layer on the chip cross section according to the conditions. Since the SD layer does not remain on the chip cross section, strength of the chip can be improved, and particles can be reduced. Conditions under which “no SD layer” can be set for the finish cross section will be described with reference to
As shown in
The control part 8 determines the recipe (the processing condition) including the irradiation condition of the laser beam by the laser irradiation unit 3 based on the wafer processing information received through the display 150 (a variety of information received on the setting screens of
As shown in
When there is a deviation (there is a parameter that is deviated) between the wafer processing information of the proposed recipe selected by performing the above-described matching process and the wafer processing information of the input information, the control part 8 may correct the deviation of parameters by calculation and simulation and may determine the recipe in which the parameters are corrected as the proposed recipe. For example, the control part 8 may correct the Z height according to a difference in the wafer thickness when the wafer thicknesses are different from each other, may correct the output of the laser beam according to a difference in the resistance value when the resistance values are different from each other, may correct the frequency of the laser beam according to a difference in speed when the speed is different, and may correct the number of focal points according to a difference in the number of passes when the number of passes is different.
By referring to the database, the control part 8 may extract a plurality of recipe candidates that are candidates for the processing condition (the recipe) corresponding to the wafer processing information that has received the input and may control the display 150 so that the plurality of recipe candidates are displayed. In an example shown in
The control part 8 may derive the degree of matching with the wafer processing information (the input information) that has received an input for each of the plurality of recipe candidates and may control the display 150 so that the plurality of recipe candidates are displayed in a display mode considering the degree of matching. Specifically, the control part 8 may control the display 150 so that, for example, the degree of matching in the plurality of recipe candidates is displayed, or the recipe candidate having a high degree of matching and the recipe candidate having a low degree of matching are displayed separately. Further, the control part 8 may control the display 150 so that a recommended order according to the degree of matching of the plurality of recipe candidates is displayed. Further, the control part 8 may control the display 150 so that a variety of information (recipe features) that can be used as a basis of determination for the user to select a recipe from the plurality of recipe candidates is displayed.
The display 150 receives a user input for selecting one recipe candidate in a state in which the plurality of recipe candidates are displayed. Then, the control part 8 may determine the recipe candidate selected in the user input received by the display 150 as the recipe (the processing condition).
The control part 8 may additionally control the display 150 so that the determined recipe (the processing condition) is displayed.
The control part 8 may derive an estimation processing result when the wafer 20 is irradiated with laser beam by the laser irradiation unit 3 based on the determined recipe (the processing condition), and may control the display 150 so that an estimation processing result image which is an image of the estimation processing result is displayed. More specifically, the control part 8 is configured to derive the estimation processing result including the information of the modified region formed on the wafer 20 and the crack extending from the modified region when the wafer 20 is irradiated with laser beam by the laser irradiation unit 3 based on the set recipe and to control the display 150 so that the estimation processing result image in which an image diagram of the wafer 20 and an image diagram of the modified region and the crack in the wafer 20 are drawn together is displayed in consideration of the modified region and the position of the crack in the wafer 20 derived as the estimation processing result. More specifically, the estimation processing result is the position of the modified region, the extension amount of the crack extending from the modified region, the presence or absence of black streaks, and the like which are estimated based on the received wafer processing information (the input information) and the determined recipe. The control part 8 controls the display 150 so that the recipe (the processing condition) and the estimation processing result image are associated with each other and displayed together.
As shown in
The display 150 may receive an input of first correction information related to the correction of the positions of the modified regions 12a and 12b and the crack 14 displayed as the estimation processing result image in a state in which the estimation processing result image is displayed. That is, the display 150 may receive the input of the first correction information which is information for correcting the target positions of the modified regions 12a and 12b and the target position of the crack 14. In this case, the control part 8 may correct the estimation processing result based on the first correction information (that is, the information for correcting the target positions of the modified regions 12a and 12b and the target position of the crack 14), may correct various parameters of the recipe to be the corrected estimation processing result, and may control the display 150 so that the corrected recipe and the estimation processing result image based on the corrected estimation processing result are associated and displayed together.
The display 150 may receive an input of second correction information related to the correction of the recipe in the state in which the processing condition (the recipe) is displayed. In this case, the control part 8 may correct various parameters of the recipe based on the second correction information, may correct the estimation processing result based on the corrected recipe, and may control the display 150 so that the corrected recipe and the estimation processing result image based on the corrected estimation processing result are associated with each other and displayed together.
The control part 8 may control the display 150 so that an inspection condition proposal result (refer to
The displaying of the above-described estimation processing result image will be described in more detail with reference to
(Processing Process)
In the processing process, the control part 8 controls the laser irradiation unit 3 so that the wafer 20 is irradiated with the laser beam under the determined processing condition (the recipe). In detail, the control part 8 controls the laser irradiation unit 3 so that the wafer 20 is irradiated with the laser beam and the modified region and the crack extending from the modified region are formed in the wafer 20. The control part 8 starts the processing process according to the pressing of “start processing” (refer to
(Processing Result Acquisition Process)
In a processing result acquisition process, the control part 8 controls the imaging unit 4 to take an image of the processed wafer 20, thereby acquiring a laser processing result of the wafer 20 due to the irradiation of the laser beam. In detail, the control part 8 outputs light having permeability to the wafer 20 and controls the imaging unit 4 to take an image of the wafer 20, thereby acquiring the laser processing result including the information of the modified region formed on the wafer 20 by the irradiation of the laser beam and the crack extending from the modified region.
As described above, after the laser processing, each of the inspections selected by the user (refer to
The control part 8 can derive the thickness of the wafer 20 by a three-pattern derivation method. In a first method, the control part 8 derives the thickness of the wafer 20 based on b: the Z position of the pattern surface. The first method can be used only when the wafer 20 is a wafer having the functional element layer 22 (pattern) as described above. In a second method and a third method, the control part 8 derives the thickness of the wafer 20 based on c: the Z position of the virtual image of the end portion of the modified region 12a (SD1) on the front surface 21a side and the recipe.
In the second method, the control part 8 first derives a width of the modified region 12a based on the recipe. Specifically, the control part 8 stores, for example, a database related to the derivation of the wafer thickness (a database in which the processing condition and the width of the modified region are associated with each other) as shown in
In the third method, the control part 8 is, first, derives an estimated end position which is the position of the end portion of the modified region 12a on the front surface 21a side and is estimated from the Z height that is a processing depth of the laser beam with respect to the wafer 20, based on the recipe. The control part 8 derives the position of the end portion in consideration of a DZ rate (the position of the end portion of the modified region 12a on the front surface 21a side in consideration of the DZ rate) based on the estimated position of the end portion and a constant (the DZ rate) considering a refractive index of the silicon of the wafer 20, and derives the thickness of the wafer 20 based on the position of the end portion in consideration of the DZ rate and c: the Z position of the virtual image of the end portion of the modified region 12a (SD1) on the front surface 21a side. As shown in
A determination result of each of the inspections includes information of the laser processing result acquired by the control part 8. In the following, it is assumed that the “inspection determination result” includes the information of the “laser processing result”.
As shown in
(Processing Condition Evaluation Process)
The control part 8 evaluates the recipe (the processing condition) based on the inspection determination result (refer to
When the control part 8 evaluates that the recipe (the processing condition) is not appropriate, the control part 8 may further perform correction of the recipe (the processing condition) based on the inspection determination result including the information of the laser processing result. For example, when it is considered that the fact that the wafer 20 is thicker than expected is served as a factor of the inspection NG as described above, the control part 8 performs Z height correction, output correction, and correction of light concentration correction amount, and determines that the recipe is corrected while the BHC margin inspection is performed as correction contents. As shown in
[Inspection Method]
An inspection method of the present embodiment will be described with reference to
As shown in
Subsequently, the control part 8 determines (automatically selects) a recipe (processing condition) corresponding to the wafer processing information (a variety of information received on the setting screen of
Subsequently, the control part 8 evaluates the recipe (the processing condition) based on the inspection determination result (refer to
On the other hand, when it is determined in Step S5 that the recipe is appropriate (evaluation OK), it is determined whether or not the recipe has been changed even once (whether or not the correction process of Step S6 has been performed) (Step S7), and when the recipe has been changed, a changed recipe (a new recipe) is registered in the database (Step S8), and the process ends.
[Operation and Effect]
Next, an operation and effect of the inspection device 1 according to the present embodiment will be described.
The inspection device 1 according to the present embodiment includes the laser irradiation unit 3 that irradiates the wafer 20 with the laser beam, the imaging unit 4 that takes an image of the wafer 20, the display 150 that receives an input of information, and the control part 8, wherein the display 150 receives an input of the wafer processing information including the information on the wafer 20 and the laser processing target for the wafer 20, and the control part 8 is configured to determine the recipe (the processing condition) including the irradiation condition of the laser beam of the laser irradiation unit 3 based on the wafer processing information received by the display 150, to control the laser irradiation unit 3 so that the wafer 20 is irradiated with the laser beam according to the determined recipe, to acquire the laser processing result of the wafer 20 due to the irradiation with the laser beam by controlling the imaging unit 4 to take an image of the wafer 20, and to evaluate the recipe based on the laser processing result.
In the inspection device 1 according to the present embodiment, when the wafer processing information is input, the recipe corresponding to the wafer processing information is determined. In this way, since the recipe is automatically determined by inputting the wafer processing information, for example, the recipe (the processing condition) can be more easily determined as compared with the case in which the laser processing process is repeatedly performed while the user adjusts the processing condition to derive an appropriate recipe. Then, the inspection device 1 evaluates the recipe based on the laser processing result performed in the determined recipe. Thus, for example, the recipe (the processing condition) can be appropriately optimized by changing the recipe as necessary based on the evaluation result. As described above, according to the inspection device 1, an appropriate recipe (the processing condition) can be easily determined.
The control part 8 may determine the recipe corresponding to the wafer processing information received through the display 150 by referring to the database in which the wafer processing information and the processing condition are stored in association with each other. The recipe determination process can be simplified by determining the recipe based on the information in the database.
The control part 8 may evaluate the recipe based on the laser processing result and the wafer processing information. Thus, for example, the recipe can be evaluated based on whether or not the actual laser processing has been performed so that the laser processing target for the wafer 20 is achieved, and the recipe can be appropriately evaluated.
The control part 8 may be configured to further correct the recipe based on the laser processing result when it is evaluated that the recipe is not appropriate. Thus, when the recipe is not appropriate, the recipe can be automatically changed based on the laser processing result, and the recipe can be optimized more easily.
When the recipe is corrected, the control part 8 may be configured to further update the database based on the information including the corrected recipe. When the processing condition is determined later based on the input of the wafer processing information, it becomes possible to determine a more appropriate recipe by registering the corrected recipe in the database in this way.
The control part 8 may be configured to further control the display 150 so that the determined recipe is displayed. Due to the recipe (suggested to the user) being displayed, it is possible to inform the user a kind of recipe with which the processing is being performed, and it is possible to change the recipe, and the like based on a user's instruction as needed.
The control part 8 may extract a plurality of recipe candidates that are candidates for the recipe corresponding to the wafer processing information that has been received as an input by referring to the database and may control the display 150 so that the plurality of recipe candidates are displayed. Thus, when there are a plurality of (suitable) recipes corresponding to the processing information of the wafer 20, each of the recipes can be displayed (suggested to the user) as a recipe candidate.
The display 150 may receive a user input for selecting one recipe candidate in a state in which a plurality of recipe candidates are displayed, and the control part 8 may determine the recipe candidate selected in the user input received through the display 150 as the recipe. Thus, the recipe desired by the user can be determined from the plurality of recipe candidates based on the user's instruction.
The control part 8 may derive a degree of matching with the wafer processing information for each of the plurality of recipe candidates by referring to the database and may control the display 150 so that the plurality of recipe candidates are displayed in a display mode in consideration of the degree of matching. Thus, for example, it is possible to show the user the degree of matching, and to distinguish between recipe candidates with a high degree of matching and recipe candidates with a low degree of matching, and to display an appropriate recipe from the plurality of recipe candidates to make it easier for the user to select it.
The control part 8 may derive the estimation processing result when the wafer 20 is irradiated with the laser beam by the laser irradiation unit 3 based on the recipe and may control the display 150 so that the estimation processing result image which is an image of the estimation processing result is displayed. It is possible to show validity of the recipe to the user and make it easier for the user to determine whether or not the recipe needs to be changed by displaying a processing image when the laser processing is performed based on the recipe.
The display 150 may receive an input of first correction information related to correction of a processing position in the estimation processing result image in a state in which the estimation processing result image is displayed, and the control part 8 may correct the estimation processing result based on the first correction information and may correct the recipe so that the corrected estimation processing result is obtained. Thus, the recipe can be easily corrected based on a correction instruction of the estimation processing result image from the user who has confirmed the estimation processing result image. For the user, when the correction instruction of the estimation processing result image is issued to obtain a desired processing result, the recipe is automatically corrected according to the correction instruction, and thus the desired processing can be easily performed.
The display 150 may receive an input of second correction information related to the correction of the recipe in the state in which the recipe is displayed, and the control part 8 may correct the recipe based on the second correction information and may correct the estimation processing result based on the corrected recipe. Thus, the recipe can be easily corrected based on the correction instruction from the user, and the estimation processing result image after the recipe is corrected can be appropriately displayed.
The control part 8 may control the display 150 so that the laser processing result is displayed. Thus, the laser processing result according to the recipe can be shown to the user.
The control part 8 may control the display 150 so that a message prompting correction is displayed when the wafer processing information received through the display 150 is not appropriate. Thus, it is possible to prompt the user to make the correction when inappropriate wafer processing information is input.
The wafer processing information may include information that indicates a finish thickness of the wafer 20. Thus, for example, the recipe can be appropriately determined in consideration of the finish thickness of the wafer 20 when grinding is performed after stealth dicing.
The wafer processing information may include crack reach information that indicates whether the crack extending from the modified region formed when the wafer 20 is irradiated with the laser beam reaches or does not reach a surface of the wafer 20, and information that indicates the expected elongation amount of the crack due to grinding after irradiation of the laser beam when the crack reach information indicates that the crack do not reach the surface of the wafer 20. Thus, for example, when the crack reaches the surface of the wafer 20 by performing grinding processing after stealth dicing to cause the crack to extend, the recipe can be determined by appropriately considering an extension amount of the crack due to the grinding.
The wafer processing information may include finish cross section information that indicates whether or not the modified region formed when the wafer 20 is irradiated with the laser beam appears on the finish cross section of the wafer 20 after the laser processing and grinding are completed. Thus, for example, when the user desires not to leave the modified region on the finish cross section for the purpose of increasing strength of a chip or reducing particles, the recipe can be determined by appropriately considering information of such a finish cross section.
Although the present embodiment has been described above, the present invention is not limited to the above embodiment. For example, as shown in
Further, as shown in
Further, in the embodiment, it has been described that the display displays the estimation processing result image in which the image diagram of the wafer and the image diagram of the modified region and the crack in the wafer are drawn together, but the present invention is not limited thereto. That is, the control part does not necessarily have to display the above-described estimation processing result image on the display, may derive, for example, an estimation processing result including information on the modified region formed in the wafer and the crack extending from the modified region, and may control the display so that the information related to the estimation processing result is displayed. The information related to the estimation processing result does not have to be an image diagram of the wafer, the modified region, the crack, and the like, but may simply be information indicating the modified region, the position of the crack, or the like (that is, it does not have to include the image diagram).
Further, in the processing condition derivation process, it has been described that the above-described display process of the estimation processing result image and the derivation process of the wafer thickness are performed, but the display process of the estimation processing result image and the derivation process of the wafer thickness may be performed in a process other than the processing condition derivation process, for example, various processes after the processing condition is derived.
Further, in the embodiment, it has been described that the inspection device 1 determines the recipe (the processing condition) based on the wafer processing information and derives the estimation processing result, but the present invention is not limited thereto. That is, the control part of the inspection device may derive the estimation processing result based on the wafer processing information and may determine the recipe (the processing condition) based on the estimation processing result. For example, since the processing conditions can be easily determined by inputting the wafer processing information, and thus the processing conditions automatically determined in this way, the processing conditions can be more easily determined as compared with the case in which the laser processing process is repeatedly performed while the user adjusts the processing conditions to derive appropriate processing conditions.
Number | Date | Country | Kind |
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2020-039066 | Mar 2020 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2021/008237 | 3/3/2021 | WO |