wafer fabrication methods

Abstract

This invention provides a wafer processing method that reduces the hassle of registering locations without TEG (Technology for Geometric Surface Treatment) for kerf inspection or kerf inspection. The wafer processing method includes a pattern region detection step, an evaluation region setting step, and an evaluation region unfolding step. In the pattern region detection step, the period and position information of substantially identical images appearing in an captured image are detected, and the pattern region corresponding to one period is detected. In the evaluation region setting step, locations where no metal pattern has formed on a predetermined dividing line are detected and set as evaluation regions for evaluating the quality of the processing groove. In the evaluation region unfolding step, the positions of the evaluation regions within the pattern regions are recorded, and the evaluation regions are unfolded at the same locations in different pattern regions.

Description

TECHNICAL FIELD

[0001] The present application relates to a wafer processing method. BACKGROUND

[0002] In order to divide a wafer such as a semiconductor wafer or an optical device wafer, each of which is a circular plate-shaped wafer made of a base material such as silicon, sapphire, silicon carbide, gallium arsenide, or the like, into individual chips, a cutting device using a cutting tool or a laser processing device using laser light is used. In these devices, a function called kerf check, which automatically confirms whether or not a processing mark (a cutting groove or a laser processing mark) falls within a division predetermined line, whether or not a large defect is generated, and the like during processing, is used (see Patent Literature 1). In addition, in the laser processing device, a function called kerf navigation, which photographs luminescence generated by laser light irradiation to determine the quality of processing during processing, is used (see Patent Literature 2).

[0003] Patent Literature 1: Japanese Patent Application Publication No. 2005-197492

[0004] Patent Literature 2: Japanese Patent Application Publication No. 2016-104491

[0005] Patent Literature 3: Japanese Patent Application Publication No. 2017-117924

[0006] However, the kerf check in the related art has a problem in that it can not be properly performed in a region in which a TEG (Test Element Group) is formed (see Patent Literature 3). The kerf navigation also has a problem in that it can not be properly performed in a region in which a TEG is formed in that luminescence based on laser light irradiation can not be normally generated.

[0007] Therefore, an operation in which an operator finds a position in which a TEG is not present while moving the position of a microscope that photographs a wafer and registers the position in the device before processing so that the kerf check or the kerf navigation is performed at the position is generated (see Patent Literature 3). This registration operation is not only troublesome but also has a problem in that it can lead to an error of the operator since it is determined by visual observation whether or not a TEG is present. SUMMARY

[0008] Thus, an object of the present application is to provide a wafer processing method capable of reducing the trouble of an operation of registering a position in which a TEG is not present for performing a kerf check or a kerf navigation.

[0009] According to one embodiment of the present application, there is provided a method for processing a wafer on which a plurality of identical pattern regions are periodically formed on a front surface, the pattern region including a plurality of division lines crossing each other and a device region divided by the plurality of division lines, characterized by comprising: a holding step of holding a back surface side of the wafer by a holding stage; a photographing step of photographing a plurality of portions of the front surface of the wafer while relatively moving the holding stage and a photographing unit; a pattern region detecting step of detecting a period and position information of a substantially identical image appearing in the photographed image and detecting the pattern region corresponding to one period; an evaluation region setting step of detecting a position where a metal pattern is not formed on the division line and setting as an evaluation region for evaluating a dicing groove; an evaluation region developing step of recording a position of the evaluation region in the pattern region and developing the evaluation region at the same portion of a different pattern region; a processing step of processing the wafer; and a dicing groove evaluation step of photographing the evaluation region in at least two or more of the pattern regions and determining the quality of the dicing groove.

[0010] According to another embodiment of the present application, there is provided a method for processing a wafer on which a plurality of identical pattern regions are periodically formed on a front surface, the pattern region including a plurality of division lines crossing each other and a device region divided by the plurality of division lines, characterized by comprising: a holding step of holding a back surface side of the wafer by a holding stage; a photographing step of photographing a plurality of portions of the front surface of the wafer while relatively moving the holding stage and a photographing unit; a pattern region detecting step of detecting a period and position information of a substantially identical image appearing in the photographed image and detecting the pattern region corresponding to one period; an evaluation region setting step of detecting a position where a metal pattern is not formed on the division line and setting as an evaluation region for evaluating a dicing groove; an evaluation region developing step of recording a position of the evaluation region in the pattern region and developing the evaluation region at the same portion of a different pattern region; a processing step of processing the wafer by irradiating a laser beam; and a dicing groove evaluation step of photographing the evaluation region and luminescence generated by irradiation of the laser beam in processing of the evaluation region, thereby determining the quality of the processing.

[0011] Preferably, the plurality of division lines are formed in a first direction and a second direction crossing the first direction, and the pattern region detecting step is performed in both the first direction and the second direction.

[0012] The present application can reduce the trouble of registering a position where no TEG is used for performing a cut inspection or a cut tour. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a perspective view showing a structure example of a processing apparatus that implements the wafer processing method of Embodiment 1.

[0014] Figure 2 is a flowchart showing an example of a flow of the wafer processing method of Embodiment 1.

[0015] Figure 3 is a plan view showing an example of a photographing step and an evaluation region setting step in the wafer processing method of Embodiment 1. Figure 2

[0016] Figure 4 is a flowchart showing an example of a detailed flow of a pattern region detection step in the wafer processing method of Embodiment 1. Figure 2

[0017] Figure 5 is a plan view showing an example of the pattern region detection step of Embodiment 1. Figure 4

[0018] Figure 6 is a block diagram showing an example of a period determination process of a pattern region in the pattern region detection step of Embodiment 1. Figure 4

[0019] Figure 7 is a block diagram showing an example of a period determination process of a pattern region in the pattern region detection step of Embodiment 1. Figure 4

[0020] Figure 8 is a flowchart showing an example of a detailed flow of an evaluation region development step in the wafer processing method of Embodiment 1. Figure 2

[0021] Figure 9 is a diagram showing an example of a setting screen related to the evaluation region development step in the wafer processing method of Embodiment 1. Figure 2

[0022] Figure 10 is a plan view showing an example of the evaluation region development step of Embodiment 1. Figure 2

[0023] Figure 11 is a sectional view showing an example of a processing step in the wafer processing method of Embodiment 1. Figure 2

[0024] Figure 12 is a front view showing an example of a processing groove evaluation step in the wafer processing method of Embodiment 1. Figure 2

[0025] Figure 13 ​​​​​​​​​​is a flowchart showing an example of a flow of a wafer processing method of a modification of the first embodiment.

[0026] Figure 14 is a block diagram showing a structure example of a main part of a laser processing apparatus that implements a wafer processing method of the second embodiment.

[0027] Figure 15 is a sectional view showing an example of a processing step in the wafer processing method of the second embodiment.

[0028] Figure 16 is a view showing an example of a processing groove evaluation step in the wafer processing method of the second embodiment.

[0029] Explanation of reference numerals

[0030] 1: processing apparatus; 10: holding stage; 20: processing unit; 30, 526: imaging unit; 40: inspection section; 50: recording section; 60: control unit; 200: wafer; 201: front surface; 202: division intended line; 207: intersection; 208: metal pattern; 210, 212: evaluation region; 221, 222, 223: region; 260, 310: reference pattern region; 261: corner; 262, 312: pattern region; 263: pattern region boundary line; 400: cutting groove; 501: laser processing apparatus; 520: laser processing unit; 600: laser; 700: laser processing groove; 800: light emission. DETAILED DESCRIPTION

[0031] Embodiments of the present application will be described below in detail with reference to the accompanying drawings. The present application is not limited by the contents described in the following embodiments. In addition, the following described constituent elements include what can be easily conceived by those skilled in the art, and substantially the same contents. In addition, the following described structures can be appropriately combined. In addition, various omissions, substitutions, or changes of the structures can be made within a range not departing from the gist of the present application.

[0032] [First Embodiment]

[0033] A processing apparatus 1 that implements a wafer processing method of the first embodiment of the present application will be described with reference to the drawings. Figure 1 is a perspective view showing a structure example of the processing apparatus 1 that implements the wafer processing method of the first embodiment. The processing apparatus 1 is a device that performs cutting on a wafer 200 that is a processed object and forms a cutting groove 400 (see FIG. 2) that is a processing mark (processing groove) formed by the cutting processing. Figure 11 , Figure 12) a cutting device that performs so-called kerf inspection, and the following describes a manner of cutting processing and performing kerf inspection on a cutting groove 400 formed by the cutting processing. Note that the processing device 1 is not limited to this in the present application, and can also be a laser processing device that irradiates a wafer 200 with laser light to perform laser processing on the wafer 200 and performs so-called kerf inspection on a laser processed mark that is a processed groove formed by the laser processing.

[0034] In the first embodiment, as shown in FIG. 1, the wafer 200 that is cut by the processing device 1 is, for example, a round plate-shaped semiconductor wafer or an optical device wafer, etc., that uses silicon, sapphire, silicon carbide (SiC), gallium arsenide, etc., as a base material. Note that the wafer 200 is not limited to this in the present application, and can also be a package substrate, a ceramic plate, a glass plate, etc., in which the device 203 is sealed with resin. The wafer 200 has an adhesive tape 205 attached to the back surface 204 on the back surface side of the flat front surface 201, and a ring-shaped frame 206 mounted to the outer edge portion of the adhesive tape 205. Figure 1

[0035] The wafer 200 has the device 203 formed in an area divided by a plurality of division intended lines 202 formed in a second direction that forms an intersection portion 207 (see FIG. 2) with the first direction on the front surface 201. In the first embodiment, the first direction and the second direction of the wafer 200 in which the plurality of division intended lines 202 are formed in a lattice shape on the front surface 201, but the present application is not limited to this. A TEG (Test Element Group) that is an example of a metal pattern 208 (see FIG. 2) composed of metal is formed on the division intended line 202. Note that a dummy pattern for chemical mechanical polishing (CMP) can be formed on the division intended line 202. Figure 3 Figure 3

[0036] In the first embodiment, the wafer 200 has a plurality of identical pattern areas periodically formed on the front surface 201 by a mask pattern that is a reticle that is a master pattern of a circuit pattern. Specifically, the wafer 200 has the pattern areas periodically formed in the first direction and the second direction on the front surface 201, and the same TEG or dummy pattern for CMP and the device 203, etc., are formed in each of the pattern areas. The wafer 200 is not limited to this in the present application, and can be any manner as long as a plurality of identical pattern areas that include the division intended line 202 and the device 203 divided by the division intended line 202 are periodically formed on the front surface 201, whether formed by the reticle or formed in a different manner from the reticle. ​​​

[0037] As shown in Figure 1 , the processing device 1 has a holding stage 10, a processing unit 20 that performs cutting processing, a photographing unit 30, an inspection section 40, a recording section 50, and a control unit 60. As shown in Figure 1 , the processing device 1 is a dicing device having two processing units 20, that is, a two-spindle dicing saw, a so-called face-to-face dual-spindle type cutting device.

[0038] In addition, as shown in Figure 1 , the processing device 1 further has an X-axis moving unit 71, a Y-axis moving unit 72, and a Z-axis moving unit 73. The X-axis moving unit 71 relatively feeds the holding stage 10 with respect to the processing unit 20 along an X-axis direction that is one direction in a horizontal direction. The Y-axis moving unit 72 relatively feeds the processing unit 20 with respect to the holding stage 10 along a Y-axis direction that is another direction in the horizontal direction and is perpendicular to the X-axis direction. The Z-axis moving unit 73 relatively feeds the processing unit 20 with respect to the holding stage 10 along a Z-axis direction that is perpendicular to the X-axis direction and the Y-axis direction and is parallel to a vertical direction.

[0039] The holding stage 10 holds the back surface 204 side of the wafer 200 having a plurality of division predetermined lines 202. The holding stage 10 is a disc shape having a disc-shaped suction portion that has a flat holding surface 11 that holds the wafer 200 on an upper surface and is composed of a porous ceramic having a large number of pores or the like, and a frame that fixes the suction portion to a recessed portion of the upper surface central portion. The holding stage 10 is disposed so as to be movable by the X-axis moving unit 71 and rotatable by a not-shown rotary drive source. The suction portion of the holding stage 10 is connected to a not-shown vacuum suction source via a not-shown vacuum suction path, and the wafer 200 is suction-held by the entire holding surface 11. In addition, as shown in Figure 1 , a plurality of clamping portions 12 that clamp the annular frame 206 are provided around the holding stage 10.

[0040] The processing unit 20 processes the wafer 200 held by the holding stage 10 along the division intended line 202 to form a cutting groove 400. The processing unit 20 has a cutting tool 21, a spindle, and a spindle housing 22. The cutting tool 21 is subjected to a rotational motion around the Y axis to cut the wafer 200 held by the holding stage 10. The spindle is disposed along the Y axis direction to support the cutting tool 21 at the front end in a manner rotatable around the Y axis. The spindle housing 22 houses the spindle in a manner capable of a rotational motion around the Y axis. The processing unit 20 is disposed in a manner that the spindle housing 22 is movable in the Y axis direction relative to the wafer 200 held by the holding stage 10 by means of a Y axis moving unit 72 and in a manner that the spindle housing 22 is movable in the Z axis direction by means of a Z axis moving unit 73.

[0041] The shooting unit 30 shoots the front surface 201 of the wafer 200 held on the holding surface 11 of the holding stage 10, for example, an electron microscope. The shooting unit 30 has a shooting element that shoots the division intended line 202 of the wafer 200 before cutting processing and the cutting groove 400 as a processing mark of the wafer 200 after cutting processing held by the holding stage 10. The shooting element is, for example, a CCD (Charge-Coupled Device) shooting element or a CMOS (Complementary MOS) shooting element. The shooting unit 30 is capable of shooting the front surface 201 of the wafer 200 in a macro shooting setting of a low magnification (Lo) or a micro shooting setting of a high magnification (Hi). In the first embodiment, the shooting unit 30 is fixed to the processing unit 20 in a manner that moves integrally with the processing unit 20.

[0042] The shooting unit 30 shoots the wafer 200 before cutting processing held by the holding stage 10 to obtain an image for performing alignment (the alignment aligns the wafer 200 with the cutting tool 21) and the like, and outputs the obtained image to the control unit 60. In addition, the shooting unit 30 shoots the wafer 200 after cutting processing held by the holding stage 10 to obtain an image for performing so-called kerf inspection (the kerf inspection automatically confirms whether the cutting groove 400 falls in the division intended line 202, whether a large defect is generated, and the like), and outputs the obtained image to the control unit 60.

[0043] The inspection section 40 is a functional section that detects the cutting groove 400 as a processing mark formed by the processing unit 20 from an image obtained by shooting the division intended line 202, and inspects the state of the cutting groove 400 as a processing mark in accordance with a prescribed inspection item. Details of the prescribed inspection item inspected by the inspection section 40 are described later.

[0044] The recording section 50 is a functional section that records images captured by the imaging unit 30, specifically, images used for performing the above-described alignment and the like, and images used for performing the kerf inspection and the like. In addition, the recording section 50 records information related to the pattern region of the division intended line 202 and the device 203 and the like, and information of the evaluation regions 210, 212 (refer to FIG. 2) for performing the kerf inspection. Figure 10

[0045] The control unit 60 controls each of the components of the processing apparatus 1 to cause the processing apparatus 1 to perform the cutting process of the wafer 200 and each action related to the kerf inspection.

[0046] In the first embodiment, the inspection section 40, the recording section 50, and the control unit 60 include a computer system. The inspection section 40, the recording section 50, and the control unit 60 have an arithmetic processing apparatus having a microprocessor like a CPU (central processing unit), a storage apparatus having a memory like a ROM (read only memory) or a RAM (random access memory), and an input / output interface apparatus. The arithmetic processing apparatus performs arithmetic processing in accordance with a computer program stored in the storage apparatus, and outputs a control signal for controlling the processing apparatus 1 to each of the components of the processing apparatus 1 via the input / output interface apparatus.

[0047] In addition, the arithmetic processing apparatus is connected to a display unit 61 constituted by a liquid crystal display apparatus or the like that displays a state or an image or the like of each action related to the cutting process and the kerf inspection, a notification unit 62 constituted by a light emitting diode (LED) or the like that performs notification in accordance with a state of each action related to the cutting process and the kerf inspection, and an input unit 63 used when an operator inputs and registers information or the like related to the cutting process and the kerf inspection or the like. The input unit 63 is constituted by at least one of a touch panel and a keyboard or the like provided to the display unit 61.

[0048] The inspection section 40 is a functional section realized by the arithmetic processing apparatus that executes a computer program stored in the storage apparatus. The recording section 50 is realized by the storage apparatus. The control unit 60 is realized by the arithmetic processing apparatus, the storage apparatus, and the input / output interface apparatus. In the first embodiment, the inspection section 40, the recording section 50, and the control unit 60 are realized on the basis of an integrated computer system, but in the present application, this is not limiting, and for example, each section and each unit can be realized on the basis of independent computer systems.

[0049] ​In the processing apparatus 1, the control unit 60 performs a so-called kerf check at an arbitrary timing during processing of one wafer 200 from the start to the end of processing, which checks the state of the cutting groove 400 as a processing mark using the inspection unit 40.

[0050] In addition, as shown in Figure 1 the processing apparatus 1 further has a cassette 80 that accommodates the wafer 200 before and after cutting processing, a temporary storage unit 82 that temporarily stores the wafer 200 before and after accommodation in the cassette 80, a cleaning unit 90 that cleans the wafer 200 after cutting processing, and a conveyance unit 85 that conveys the wafer 200 between the holding stage 10, the cassette 80, the temporary storage unit 82, and the cleaning unit 90.

[0051] The processing apparatus 1 takes out one wafer 200 from the cassette 80 by the conveyance unit 85 and places it on the holding surface 11 of the holding stage 10. The processing apparatus 1 holds the wafer 200 by suction using the holding surface 11 of the holding stage 10 and supplies cutting water to the wafer 200 from the processing unit 20 while relatively moving the holding stage 10 and the processing unit 20 along the division predetermined line 202 by the X-axis moving unit 71, the rotation drive source, the Y-axis moving unit 72, and the Z-axis moving unit 73, and forms the cutting groove 400 by cutting the division predetermined line 202 of the wafer 200 using the processing unit 20. When the processing apparatus 1 cuts all the division predetermined lines 202 of the wafer 200, the wafer 200 is accommodated in the cassette 80 after being cleaned by the cleaning unit 90.

[0052] Figure 2 is a flowchart showing an example of the flow of the wafer processing method of the first embodiment. Hereinafter, the wafer processing method of the first embodiment will be described using Figure 2 The wafer processing method of the first embodiment performed by the processing apparatus 1 will be described. As shown in Figure 2 the wafer processing method of the first embodiment has a holding step ST11, a photographing step ST12, an evaluation region setting step ST13, a pattern region detection step ST14, an evaluation region development step ST15, a processing step ST16, and a processing groove evaluation step ST17.

[0053] The holding step ST11 is a step of holding the back surface 204 side of the wafer 200 to the holding stage 10. In the holding step ST11, specifically, the back surface 204 side of the wafer 200 conveyed and placed on the holding stage 10 by the conveyance unit 85 is held by suction using the holding surface 11 of the holding stage 10 with the adhesive tape 205 interposed therebetween, thereby holding the wafer 200 in a state in which the front surface 201 is exposed upward.

[0054] The control unit 60, after the holding step ST11, performs alignment, that is, performs positioning of the wafer 200 and the cutting tool 21 using the photographing unit 30. In the first embodiment, by this alignment, the first direction of the division predetermined line 202 in the wafer 200 on the holding stage 10 is made to coincide with the X-axis direction of the processing apparatus 1, and the second direction of the division predetermined line 202 is made to coincide with the Y-axis direction of the processing apparatus 1. In addition, by this alignment, the position information of the formed division predetermined line 202 in the wafer 200 on the holding stage 10 is recorded in the recording section 50 in the form of X, Y coordinates, and becomes a state in which processing can be performed in the information processing in the form of X, Y coordinates using the control unit 60.

[0055] The photographing step ST12 is performed after the holding step ST11, and the holding stage 10 and the photographing unit 30 are relatively moved while photographing a plurality of portions of the front surface 201 of the wafer 200.

[0056] In the photographing step ST12, the control unit 60 then photographs, by the photographing unit 30, an image of the front surface 201 of the wafer 200 before cutting processing, which is held by the holding stage 10. At this time, the front surface 201 can be divided into a plurality of portions to acquire an image in which the positions of all the division predetermined lines 202 can be recognized. In the photographing step ST12, the control unit 60 can photograph a macro image by the photographing unit 30 in a macro photographing setting at a low magnification, can photograph a micro image in a micro photographing setting at a high magnification, or can photograph both the macro image and the micro image.

[0057] Figure 3 is a drawing showing an example of the photographing step ST12 and the evaluation region setting step ST13 in the processing method of the wafer of Figure 2 In the photographing step ST12, in the case where the control unit 60 photographs a macro image by the photographing unit 30 in a macro photographing setting at a low magnification, as shown in Figure 3 , the entire front surface 201 of the wafer 200 can be photographed, and the photographed images can be connected to synthesize one large image. In the photographing step ST12, as shown in Figure 3 , the control unit 60 can display the entire image of the front surface 201 of the wafer 200 and an enlarged image of a part on the display unit 61. In the photographing step ST12, the control unit 60 records the image photographed by the photographing unit 30 in the recording section 50.

[0058] The evaluation region setting step ST13 is performed after the alignment and the photographing step ST12, detects a position and a region in which the metal pattern 208 such as a TEG is not formed on the division predetermined line 202, and sets a part of the region in which the metal pattern 208 is not formed as an evaluation region 210 in which the quality of the processing groove, that is, the cutting groove 400 is evaluated.

[0059] In the evaluation region setting step ST13, specifically, the control unit 60 first detects the position and region in which the metal pattern 208 such as TEG is formed on the division predetermined line 202, based on the image obtained in the photographing step ST12. Thereby, in the evaluation region setting step ST13, the control unit 60 can recognize the position and region in which the metal pattern 208 such as TEG is not formed on the division predetermined line 202.

[0060] In the evaluation region setting step ST13, the control unit 60 can also display the image of the metal pattern 208 on the display unit 61 in a manner that the entire image of the front surface 201 of the wafer 200 and the enlarged image of a part thereof are overlapped. Thereby, in the evaluation region setting step ST13, the operator can recognize the position and region in which the metal pattern 208 is not formed, by the entire image of the front surface 201 of the wafer 200 and the enlarged image of a part thereof displayed on the display unit 61.

[0061] In the evaluation region setting step ST13, the operator then selects a region in which the evaluation of the cutting groove 400 after the formation of the cutting groove 400 is desired, from the region in which the metal pattern 208 is not displayed, while recognizing the entire image of the front surface 201 of the wafer 200 and the enlarged image of a part thereof displayed on the display unit 61, and inputs via the input unit 63. Upon acceptance of the input, the control unit 60 recognizes and sets the region corresponding to the selected and input region as the evaluation region 210 in the evaluation region setting step ST13. In addition, in the case where the region in which the metal pattern 208 is displayed is selected and input by the operator, the control unit 60 does not perform the setting of the evaluation region 210, displays a response display that the setting of the region corresponding to the selected and input region as the evaluation region 210 is not possible on the display unit 61, and requests the input of the region to be set as the evaluation region 210 again. In addition, in the first embodiment, only one evaluation region 210 is set in the evaluation region setting step ST13, but the present application is not limited thereto, and two or more evaluation regions 210 can be set. In addition, in the evaluation region setting step ST13, the operator can also set by searching for the region in which the metal pattern 208 is not formed while moving the photographing region and confirming the photographed image.

[0062] The pattern region detection step ST14 is implemented at least after the alignment and photographing step ST12, and the control unit 60 detects one pattern region by detecting the period and position information of the substantially same image appearing in the photographed image. In addition, in the first embodiment, one pattern region detected in the pattern region detection step ST14 corresponds to one intermediate mask, but the present application is not limited thereto, and can correspond to a plurality of one pattern regions formed periodically regardless of the intermediate mask.

[0063] In the first embodiment, the pattern region detection step ST14 is performed by the control unit 60 in both the X-axis direction corresponding to the first direction of the division predetermined line 202 and the Y-axis direction corresponding to the second direction of the division predetermined line 202, the results are combined, and the period and position information of the pattern region in the planar direction (XY plane direction) are detected from the period and position information in the first direction (X-axis direction) and the period and position information in the second direction (Y-axis direction). In addition, since the pattern region detection step ST14 in the X-axis direction corresponding to the first direction and the pattern region detection step ST14 in the Y-axis direction corresponding to the second direction are the same except for the orientation in which the pattern region detection step ST14 is performed, only the pattern region detection step ST14 performed in the X-axis direction corresponding to the first direction will be described in detail below, and the detailed description of the pattern region detection step ST14 performed in the Y-axis direction corresponding to the second direction will be omitted.

[0064] Figure 4 is an example of a flowchart showing the detailed flow of the pattern region detection step ST14 in the wafer processing method of Figure 2 . Figure 5 is an example of a diagram showing the pattern region detection step ST14 of Figure 4 . Figure 6 is an example of a diagram showing the period determination process of the pattern region in the pattern region detection step ST14 of Figure 4 . Figure 7 is an example of a diagram showing the period determination process of the pattern region in the pattern region detection step ST14 of Figure 4 . Hereinafter, the pattern region detection step ST14 in the wafer processing method of the first embodiment will be described in detail using Figure 4 , Figure 5 , Figure 6 , and Figure 7 .

[0065] In the pattern region detection step ST14 performed in the X-axis direction corresponding to the first direction, first, the control unit 60 sets the Y coordinate at which the image acquisition is performed to a Y coordinate at which a characteristic image is more easily displayed due to the presence of the intersection portion 207 of the division predetermined line 202 (step ST21). In the example of the first embodiment shown in Figure 5 , the control unit 60 sets the coordinate Y1 as the Y coordinate at which the image acquisition is performed.

[0066] In the pattern region detection step ST14, after the step ST21 is implemented, the control unit 60 acquires images of the regions divided by every one rotation in the X-axis direction at the Y coordinate set in the step ST21 (step ST22). Here, one rotation refers to the distance between adjacent division predetermined lines 202. One rotation in the X-axis direction and one rotation in the Y-axis direction are the same distance in the first embodiment, but in the present application, they are not limited to this, and can be different distances. In the step ST22, the control unit 60 can acquire a macro image, can acquire a micro image, or can acquire both a macro image and a micro image. In the step ST22, in the example of the first embodiment shown in FIG. 8, the control unit 60 acquires each image in the plurality of regions 221 at the coordinate Yl. Figure 5

[0067] In the pattern region detection step ST14, after the step ST22 is implemented, the control unit 60 determines whether a characteristic image periodically appears in the image acquired by the step ST22 (step ST23). In the step ST23, in a case where the control unit 60 determines that a characteristic image periodically appears (YES in the step ST23), the processing proceeds to a step ST24. In the step ST24, the control unit 60 determines that a period in which a characteristic image appears in the X-axis direction is present at the Y coordinate set in the previous step (here, the step ST21).

[0068] In the step ST23, in a case where the control unit 60 determines that a characteristic image does not periodically appear (NO in the step ST23), the processing proceeds to a step ST25. Figure 5 In the example of the first embodiment shown in FIG. 8, the control unit 60 determines that a characteristic image appears in the plurality of regions 221 at the coordinate Yl in a period of three rotations of [A, B, C] as one group (YES in the step ST23), and in the subsequent step ST24, determines that a period of three rotations in the X-axis direction is present at the coordinate Yl.

[0069] In the pattern region detection step ST14, after the step ST24 is implemented, the control unit 60 determines whether the determination of the period in the X-axis direction in the step ST24 has been performed a prescribed number of times (step ST25). That is, in the step ST25, the control unit 60 determines whether the period in the X-axis direction determined by the step ST24 is obtained at a prescribed number of different Y coordinates.

[0070] In the step ST25, in a case where the control unit 60 determines that the determination of the period in the X-axis direction in the step ST24 has been performed a prescribed number of times (YES in the step ST25), the period of the pattern region in the X-axis direction is determined from the information of the prescribed number of periods determined in the step ST24 (step ST26).

[0071] ​In step ST25, Figure 5 In the example of the first embodiment shown, when the control unit 60 is set to be sufficient to determine the period along the X-axis direction by one determination on a Y-coordinate, it is determined that the period along the X-axis direction has been determined a predetermined number of times based on the determination of three rotations on coordinate Y1 (yes in step ST25). In the subsequent step ST26, based on the information of the three rotations on coordinate Y1, it is determined that the period along the X-axis direction of the pattern area is three rotations.

[0072] On the other hand, in step ST25, if the control unit 60 determines that the period determination along the X-axis in step ST24 has not been performed a predetermined number of times (no in step ST25), the Y-coordinate for image acquisition is rotated along the Y-axis (step ST27), and the process returns to step ST22. Furthermore, in the first embodiment, step ST27 involves rotating the Y-coordinate for image acquisition in the +Y direction; however, this invention is not limited to this, and a rotation in the -Y direction may also be performed.

[0073] In step ST25, Figure 5 In another example of the first embodiment shown, if the control unit 60 is set to require a total of two determinations on two Y coordinates to determine the period along the X-axis, it is determined that the period determination along the X-axis has not been performed a prescribed number of times based on the determination of three rotations on coordinate Y1 (no in step ST25). In the subsequent step ST27, the Y coordinate for image acquisition is moved from coordinate Y1 by one rotation along the Y-axis and set to coordinate Y2. Step ST22 and the processing after step ST22 are performed again with respect to the newly set coordinate Y2.

[0074] exist Figure 5In this other example of the first embodiment, the control unit 60 acquires the images in the regions 222 at the coordinates Y2 in step ST22. Then, in step ST23, the control unit 60 determines that the characteristic image appears periodically in the regions 222 at the coordinates Y2 in three shifts of the period [D, E, F] as one group (YES in step ST23), and determines that the period in the X-axis direction at the coordinates Y2 has three shifts in step ST24. Then, the process returns to step ST25, and the control unit 60 determines that the determination of the period in the X-axis direction has been performed a predetermined number of times, i.e., twice, based on the fact that the period in the X-axis direction has been determined at the coordinates Yl and Y2 (YES in step ST25), and determines that the period in the X-axis direction of the pattern region is three shifts based on the information of the period in the X-axis direction at the coordinates Yl and Y2 in step ST26.

[0075] Thus, in step ST25, when the determination of the period in the X-axis direction at a plurality of Y coordinates is set to be performed a plurality of times, the period in the X-axis direction of the pattern region can be derived based on the information of the period in the X-axis direction at a plurality of Y coordinates in step ST26, and thus the period in the X-axis direction of the pattern region can be derived more accurately.

[0076] In step ST26, more specifically, as shown in Figure 6 In the case where the control unit 60 performs the information processing of deriving the period information 241 of the pattern region in the X-axis direction based on the period information 231, 232 in the X-axis direction at a plurality of Y coordinates, the period information 241 of the pattern region in the X-axis direction is derived as the least common multiple of the period Xl (expressed in the number of shifts) in the period information 231 and the period X2 (expressed in the number of shifts) in the period information 232. Thus, in step ST26, the control unit 60 can derive the period information 241 of the pattern region in the X-axis direction more accurately.

[0077] Here, in step ST23, when the control unit 60 determines that the characteristic image does not appear periodically in the regions at the set Y coordinates (NO in step ST23), the process proceeds to step ST28. In the pattern region detection step ST14, the control unit 60 determines whether the steps ST22 and ST23 have been performed a predetermined number of times in step ST28 (step ST28).

[0078] In the step ST28, in a case where the control unit 60 determines that the steps ST22 and ST23 are not executed for the prescribed number of times (NO in the step ST28), the Y coordinate at which the image acquisition is performed is moved by one pitch in the Y axis direction (step ST27), and the processing is returned to the step ST22. Here, it is considered that in a case where the steps ST22 and ST23 are not executed for the prescribed number of times, the possibility that the characteristic image appears at the other intersection portion 207 is sufficiently high, and thus in the pattern region detection step ST14 of the first embodiment, the image processing at the other intersection portion 207 is urged.

[0079] In the step ST28, in a case where the control unit 60 determines that the steps ST22 and ST23 are executed for the prescribed number of times (YES in the step ST28), the Y coordinate at which the image acquisition is performed is moved to a position apart from the intersection portion 207 of the division predetermined line 202 (step ST29), and the processing is returned to the step ST22. Here, it is considered that in a case where the steps ST22 and ST23 are executed for the prescribed number of times, the possibility that the characteristic image appears at the other intersection portion 207 is sufficiently low, and thus in the pattern region detection step ST14 of the first embodiment, the image processing in the plurality of regions 223 on the division predetermined line 202 other than the intersection portion 207, for example, as shown in FIG. 7, is urged. Figure 5

[0080] In addition, in the first embodiment, in the pattern region detection step ST14, the image of a part of the region is used to determine the period of the X axis direction of the pattern region, but in the present application, this is not limited thereto, and the image can be continuously acquired along the X axis direction for all of the division predetermined lines 202, and the continuous image of the entire division predetermined line 202 is used to determine the period of the X axis direction of the pattern region based on the characteristic image that appears periodically.

[0081] In the pattern region detection step ST14, when the control unit 60 ends the entire flow in the two directions of the X axis direction corresponding to the first direction and the Y axis direction corresponding to the second direction of the division predetermined line 202 as shown in FIG. 6, the information processing of combining the period information 241 of the X axis direction of the pattern region derived by performing in the X axis direction corresponding to the first direction and the period information 242 of the Y axis direction of the pattern region derived by performing in the Y axis direction corresponding to the second direction is implemented. Figure 4 Figure 7

[0082] ​​​Here, the period and position information 250 of the pattern region includes information of the size of the pattern region, information of a reference pattern region 260 defined by XY coordinates of at least one corner, and information of other pattern regions 262. In the pattern region detection step ST14, specifically, the control unit 60 determines the period Xa (in number of pitches) of the pattern region in the X-axis direction in the period information 241 and the period Yb (in number of pitches) of the pattern region in the Y-axis direction in the period information 242 as the size of the pattern region in each direction, sets the prescribed reference pattern region 260, defines the reference pattern region 260 with the XY coordinates of the four corners 261, and defines the other pattern regions 262 with the separation period in the XY direction from the reference pattern region 260.

[0083] In the outer peripheral portion of the front surface 201 of the wafer 200, the number of the set division intended lines 202 is small, and thus the pattern region is mostly in a state of being interrupted. In view of this, in the first embodiment, the prescribed reference pattern region 260 set in the pattern region detection step ST14 is preferably set in the vicinity of the center of the front surface 201 of the wafer 200, and in this case, the reference pattern region 260 can be more reliably handled as a complete pattern region without interruption.

[0084] In the pattern region detection step ST14, the control unit 60 defines the pattern region boundary line 263 between the reference pattern region 260 and the other pattern regions 262 and between the other pattern regions 262 in the wafer 200. Figure 5 In the example of the first embodiment shown in FIG. 6, a pattern region of which the period in the X-axis direction is three pitches and the period in the Y-axis direction is four pitches, that is, a 3 x 4 pattern region, is detected, the reference pattern region 260 is defined with the XY coordinates of the four corners 261 in the vicinity of the center of the front surface 201 of the wafer 200, and the other pattern regions 262 are defined with the separation period in the XY direction from the reference pattern region 260. In addition, in the pattern region detection step ST14, the control unit 60 can define the pattern region boundary line 263 between the reference pattern region 260 and the other pattern regions 262 and between the other pattern regions 262 in this example.

[0085] The evaluation region expansion step ST15 is performed after the evaluation region setting step ST13 and the pattern region detection step ST14, and expands the evaluation region 210 set in the evaluation region setting step ST13 on the front surface 201 of the wafer 200 based on the period and position information 250 of the pattern region acquired in the pattern region detection step ST14.

[0086] Figure 8 is a flowchart showing a detailed flow of the evaluation region expansion step ST15 in the processing method of the wafer of Figure 2 Figure 9 is a flowchart showing a detailed flow of the evaluation region expansion step ST15 in the processing method of the wafer of Figure 2 ​Fig. 1 is a diagram showing an example of the setting screen 300 related to the evaluation region expansion step ST15 in the wafer processing method of the first embodiment. Figure 10 is a diagram showing Figure 2 an example of the evaluation region expansion step ST15 in the wafer processing method of the first embodiment. Hereinafter, the evaluation region expansion step ST15 in the wafer processing method of the first embodiment will be described in detail using Figure 8 , Figure 9 and Figure 10 .

[0087] In the evaluation region expansion step ST15, first, the control unit 60 determines the reference pattern region 310 including the reference coordinates (X, Y) of the evaluation region 210 set in the evaluation region setting step ST13 (step ST31).

[0088] In the evaluation region expansion step ST15, the control unit 60 at least after the step ST31, as shown in Fig. 3, sets the evaluation region 212 for confirming the state of the processing groove in accordance with the number of pattern regions input in the setting screen 300 of the evaluation region 210 shown in Fig. 2, with the reference pattern region 310 determined in the step ST31 as a reference (step ST32). Figure 10 Figure 9 The setting screen 300 of the evaluation region 210 is one way of the screen displayed on the display unit 61 by the control unit 60, as shown in Fig. 2, is a screen for accepting the input from the operator with respect to expansion of the evaluation region 210 by every several pattern regions for Chl and expansion of the evaluation region 210 by every several pattern regions for Ch2. In the setting screen 300 of the first embodiment example shown in Fig. 2, Chl indicates an input item for a value in the X axis direction corresponding to the first direction, and Ch2 indicates an input item for a value in the Y axis direction corresponding to the second direction. In the setting screen 300 of the first embodiment example shown in Fig. 2, 2 is input in Chl to input the meaning of expansion of the evaluation region 210 by every two pattern regions in the X axis direction corresponding to the first direction, and 2 is input in Ch2 to input the meaning of expansion of the evaluation region 210 by every two pattern regions in the Y axis direction corresponding to the second direction.

[0089] The setting screen 300 of the evaluation region 210 is one way of the screen displayed on the display unit 61 by the control unit 60, as shown in Fig. 2, is a screen for accepting the input from the operator with respect to expansion of the evaluation region 210 by every several pattern regions for Chl and expansion of the evaluation region 210 by every several pattern regions for Ch2. In the setting screen 300 of the first embodiment example shown in Fig. 2, Chl indicates an input item for a value in the X axis direction corresponding to the first direction, and Ch2 indicates an input item for a value in the Y axis direction corresponding to the second direction. In the setting screen 300 of the first embodiment example shown in Fig. 2, 2 is input in Chl to input the meaning of expansion of the evaluation region 210 by every two pattern regions in the X axis direction corresponding to the first direction, and 2 is input in Ch2 to input the meaning of expansion of the evaluation region 210 by every two pattern regions in the Y axis direction corresponding to the second direction. Figure 9 Figure 9 Figure 9

[0090] In the step ST32, in the first embodiment example shown in Figs. 2 and 3, the meaning of expansion of the evaluation region 210 by every two pattern regions in the X axis direction and the Y axis direction is input, and therefore the control unit 60 sets four evaluation regions 212 disposed at positions of every two pattern regions from the reference pattern region 310 as a starting point. Figure 9 Figure 10 ​​​​​​

[0091] Thus, in the evaluation region expansion step ST15, a plurality of evaluation regions 212 can be set at once in a manner that the evaluation region 210 is expanded into a plurality of pattern regions 312 in accordance with the input conditions with the reference pattern region 310 as a starting point.

[0092] Figure 11 is a view showing an example of the processing step ST16 in the processing method of the wafer of Figure 2 . The processing step ST16 is performed after the evaluation region expansion step ST15, and the wafer 200 is processed by the processing unit 20. In the first embodiment, in the processing step ST16, specifically, as shown in Figure 11 , the control unit 60 causes the holding work table 10 to hold the wafer 200 formed in the holding step ST11 with the front surface 201 side exposed, and causes the cutting tool 21 installed in the processing unit 20 to rotate around the axis while supplying the cutting fluid 24 from the cutting fluid supply portion 23 of the processing unit 20 to the front surface 201 of the wafer 200. In the processing step ST16, next, the control unit 60 causes the holding work table 10 or the cutting tool 21 of the processing unit 20 to be processed fed, indexed fed, and cut fed by the X-axis moving unit 71, the Y-axis moving unit 72, and the Z-axis moving unit 73 while the cutting tool 21 is rotated around the axis, thereby performing cutting processing along the division predetermined line 202 from the front surface 201 side of the wafer 200. In the processing step ST16, by such cutting processing, the cutting groove 400 is formed along the division predetermined line 202 on the front surface 201 side of the wafer 200.

[0093] In addition, the processing step ST16 is performed by the control unit 60 in the same manner as the pattern region detection step ST14 in both the X-axis direction corresponding to the first direction of the division predetermined line 202 and the Y-axis direction corresponding to the second direction of the division predetermined line 202, the cutting groove 400 is formed along the division predetermined line 202 in the X-axis direction, and the cutting groove 400 is formed along the division predetermined line 202 in the Y-axis direction.

[0094] The processing groove evaluation step ST17 is performed after the processing step ST16, and the control unit 60 performs imaging of the evaluation regions 210, 212 in the at least two or more pattern regions by the imaging unit 30, performs imaging of the cutting groove 400, and performs determination of the good or bad by the inspection section 40. That is, in the processing groove evaluation step ST17, the control unit 60 performs imaging of the evaluation regions 210, 212 by the imaging unit 30 with respect to the evaluation region 210 and the at least one or more evaluation regions 212 set in the evaluation region expansion step ST15 on the basis of the evaluation region 210, performs imaging of the cutting groove 400, and performs so-called kerf inspection with respect to the imaged image of the cutting groove 400 by the inspection section 40. In addition, in the first embodiment, the control unit 60 performs the so-called kerf inspection with respect to the evaluation region 210 and all of the evaluation regions 212 in the processing groove evaluation step ST17.

[0095] In addition, the processing groove evaluation step ST17 is performed by the control unit 60 in the same manner as the pattern region detection step ST14 and the processing step ST16 in the two directions of the X-axis direction corresponding to the first direction of the division predetermined line 202 and the Y-axis direction corresponding to the second direction of the division predetermined line 202, performs imaging of the cutting groove 400 along the X-axis direction to determine the good or bad, and performs imaging of the cutting groove 400 along the Y-axis direction to determine the good or bad.

[0096] In the first embodiment, in the processing groove evaluation step ST17, the control unit 60 can set, for example, as an inspection item of the so-called kerf inspection, whether or not the position of the edge of the cutting groove 400 deviates from a prescribed threshold value, whether or not the width 401 of the cutting groove 400 is too thin, whether or not the burr size is larger than a set threshold value, and the like. In addition, the control unit 60 displays a prescribed dedicated setting screen, not shown, on the display unit 61 with respect to these settings, and thus can accept input of the settings through the setting screen.

[0097] Figure 12 is a drawing illustrating an example of the processing groove evaluation step ST17 in the wafer processing method of Figure 2 . An example of the processing groove evaluation step ST17 in the wafer processing method of the first embodiment is explained with reference to an inspection screen in an arbitrary one of the evaluation regions 212. As Figure 12As shown, the inspection screen in any one of the evaluation regions 212 shows the state where the cutting groove 400 falls within the width 202-1 of the division predetermined line 202, the center line 402 of the cutting groove 400 is substantially identical to the center line 202-2 of the division predetermined line 202, that is, the offset 403 of the center line 402 with respect to the width direction of the center line 202-2 is substantially 0, the position of the edge of the cutting groove 400 does not deviate from the threshold value, the width 401 of the cutting groove 400 is not too thin, and no edge collapse is generated and thus the edge collapse size is not greater than the threshold value. Thus, in the machining groove evaluation step ST17, the control unit 60 determines that all the inspection items for which the cutting groove 400 is set are passed, that is, are excellent, in the evaluation region 212 by the inspection section 40. In the machining groove evaluation step ST17, the control unit 60 displays the content of the excellent determination on the display unit 61 or the like, so that the operator can be notified.

[0098] The wafer machining method of the first embodiment has the above structure, and thus detects the position where the metal pattern 208 is not formed on the division predetermined line 202 in the evaluation region setting step ST13, sets the evaluation region 210 that evaluates the excellence or inferiority of the cutting groove 400 as the machining groove, and detects the period and position information of the pattern region that appears substantially the same in the captured image in the pattern region detection step ST14, and detects the pattern region corresponding to one intermediate mask. Thus, the wafer machining method of the first embodiment has the following operational effects: the operator is not forced to perform a new registration work, and the evaluation region 210 of the region where the metal pattern 208 is not formed that is set in the evaluation region setting step ST13 is spread on the front surface 201 of the wafer 200 in the evaluation region spreading step ST15 based on the period and position information 250 of the pattern region detected in the pattern region detection step ST14, and similarly, the evaluation region 212 can be newly set in the region where the metal pattern 208 is not formed. The wafer machining method of the first embodiment has the following operational effects in particular: the operator can automatically set the evaluation regions 210, 212 of different pattern regions in the region where the metal pattern 208 is not formed by setting only one evaluation region 210 in the region where the metal pattern 208 is not formed. That is, the wafer machining method of the first embodiment has the following operational effects: the trouble of the work of registering the position of the metal pattern 208 such as the TEG or the like that is not used to perform the so-called kerf inspection that evaluates the excellence or inferiority of the cutting groove 400 can be reduced. In addition, the wafer machining method of the first embodiment can more reliably avoid the metal pattern 208 such as the TEG or the like to perform the kerf inspection compared to the past, and thus can stabilize the kerf inspection.

[0099] In the wafer processing method of the first embodiment, the plurality of division intended lines 202 are formed in the first direction (X-axis direction) and the second direction (Y-axis direction) intersecting the first direction (X-axis direction), and the pattern region detection step ST14 is performed in both the first direction (X-axis direction) and the second direction (Y-axis direction). Thus, the wafer processing method of the first embodiment has the following effect: the period of the pattern region is detected for both the first direction (X-axis direction) and the second direction (Y-axis direction), so that the evaluation region 210 can be spread into the evaluation region 212 in both the first direction (X-axis direction) and the second direction (Y-axis direction) in the evaluation region spreading step ST15.

[0100] [Modified Example]

[0101] A wafer processing method of a modified example of the first embodiment of the present application will be described with reference to the drawings. Figure 13 FIG. 1 is a flowchart showing an example of a flow of the wafer processing method of the modified example of the first embodiment. Figure 13 In the modified example of the first embodiment, the same reference numerals are attached to the same parts as those of the first embodiment, and the description thereof will be omitted.

[0102] In the wafer processing method of the modified example of the first embodiment, the implementation order of the evaluation region setting step ST13 and the pattern region detection step ST14 is exchanged from that of the wafer processing method of the first embodiment, and the other structures are the same. In the wafer processing method of the modified example of the first embodiment, after the alignment and photographing step ST12, the control unit 60 implements the pattern region detection step ST14, and sets a part of the region in the pattern region corresponding to one period, in which the metal pattern 208 is not formed as in the first embodiment, as the evaluation region 210 that evaluates the quality of the cutting groove 400 as the processing groove, by the evaluation region setting step ST13 implemented later. In addition, in the wafer processing method of the modified example of the first embodiment, in the case where a plurality of evaluation regions 210 are set, the setting can be performed from one pattern region or from two or more pattern regions.

[0103] In the wafer processing method of the modified example of the first embodiment, in the evaluation region setting step ST13, the input of the evaluation region 210 can be processed in conjunction with the input of the reference pattern region 310. That is, in the wafer processing method of the modified example of the first embodiment, in the evaluation region setting step ST13, the input of the evaluation region 210 for which the input is accepted can be processed as the input of the evaluation region 210 in the reference pattern region 310.

[0104] The wafer processing method of the modification of the first embodiment has the above structure, and thus the implementation order of the evaluation region setting step ST13 and the pattern region detection step ST14 is exchanged in the wafer processing method of the first embodiment, and thus the same effects as the wafer processing method of the first embodiment are exerted.

[0105] [Second Embodiment]

[0106] The wafer processing method of the second embodiment of the present application will be described with reference to the drawings. Figure 14 is a block diagram showing a structure example of a main part of a laser processing apparatus 501 that implements the wafer processing method of the second embodiment. Figure 15 is a view showing an example of the processing step ST16 in the wafer processing method of the second embodiment.

[0107] Figure 16 is a view showing an example of the processing groove evaluation step ST17 in the wafer processing method of the second embodiment.

[0108] Figure 14 、 Figure 15 and Figure 16 In the first embodiment, the same reference numerals are attached to the same parts as those of the first embodiment, and the description thereof is omitted.

[0109] As shown in Figure 14 , the laser processing apparatus 501 is obtained by changing the processing unit 20 and the photographing unit 30 into a laser processing unit 520 in the processing apparatus 1 and changing the functions of the inspection section 40, the recording section 50, and the control unit 60 into laser processing and kerf review specifications in conjunction therewith, and has the same structure as the processing apparatus 1 except for this. The workpiece of the laser processing apparatus 501 is also the wafer 200 as in the processing apparatus 1.

[0110] As shown in Figure 14 、 Figure 15 and Figure 16 , the laser processing apparatus 501 is a laser processing apparatus that performs so-called kerf review as follows: laser light (laser light ray) 600 is irradiated to the wafer 200 to perform laser processing on the wafer 200, and the wafer 200 in a prescribed region and luminescence 800 generated by the laser light irradiation are photographed in the laser processing to determine the merits and demerits of the processing state.

[0111] The laser processing unit 520 processes the wafer 200 held by the holding stage 10 along the division predetermined line 202 to form a laser processing groove 700 (see Figure 16). As for the laser processing unit 520, the irradiation position of the laser 600 is arranged to be movable in the Y-axis direction by the Y-axis moving unit 72 and in the Z-axis direction by the Z-axis moving unit 73 with respect to the wafer 200 held by the holding stage 10. On the other hand, the holding stage 10 is arranged to be movable in the X-axis direction by the X-axis moving unit 71 with respect to the irradiation position of the laser 600 based on the laser processing unit 520.

[0112] As shown in Fig. 2, the laser processing unit 520 has a laser oscillation unit 521, a condenser 522, a dichroic mirror 523, a stroboscopic light irradiation unit 524, a beam splitter 525, and a photographing unit 526. Figure 14

[0113] The laser oscillation unit 521 has a laser oscillator and a repetition frequency setting section, which are not shown. The laser oscillator of the laser oscillation unit 521 is a device that oscillates the laser 600 of a prescribed wavelength, and in the second embodiment, as a preferred laser oscillator, a laser oscillator that oscillates the laser of a wavelength of about 1 μm by exciting a YAG crystal or the like doped with neodymium (Nd) ions or the like by a laser diode (LD) is used. The repetition frequency setting section of the laser oscillation unit 521 is a functional section that sets the repetition frequency of the laser oscillated by the oscillator, and in the second embodiment, as a preferred repetition frequency setting section, a repetition frequency setting section that sets the repetition frequency to twice and oscillates the laser 600 of a wavelength of about 514 nm, which is the second harmonic wave of the above-described laser of a wavelength of about 1 μm, is used. In the second embodiment, the laser oscillation unit 521 is controlled by the control unit 60 to oscillate the laser 600 of a pulsed laser beam having a repetition frequency of 50 kHz or more and 200 kHz or less, an average output of 0.1 W or more and 2.0 W or less, and a pulse width of 20 ps or less.

[0114] The condenser 522 is an optical device that condenses the laser 600 oscillated from the laser oscillation unit 521 and irradiates it toward the wafer 200 held by the holding stage 10, and for example, a condenser lens is preferably used.

[0115] The dichroic mirror 523 is an optical device that reflects light of the frequency of the vicinity of the laser 600 oscillated from the laser oscillation unit 521 and transmits light of other frequencies. The dichroic mirror 523 reflects the laser 600 oscillated from the laser oscillation unit 521 and introduces it to the condenser 522. The dichroic mirror 523 transmits the stroboscopic light 650 emitted from the stroboscopic light irradiation unit 524 and introduces it to the condenser 522. The dichroic mirror 523 transmits the luminescence 800 from the wafer 200 held by the holding stage 10 and introduces it to the beam splitter 525.

[0116] ​The stroboscopic light irradiation unit 524 has a stroboscopic light source not shown and an optical system not shown. The stroboscopic light source of the stroboscopic light irradiation unit 524 is a device that emits a prescribed stroboscopic light 650, and in the second embodiment, a xenon flash lamp that emits prescribed white light is used as the preferred stroboscopic light source. The optical system of the stroboscopic light irradiation unit 524 guides the stroboscopic light 650 emitted from the stroboscopic light source to the beam splitter 525, and as the preferred optical system, an optical system in which an optical stop, a condenser lens, and a turning mirror are arranged in that order from the stroboscopic light source side is used.

[0117] The beam splitter 525 guides the stroboscopic light 650 emitted from the stroboscopic light irradiation unit 524 to the dichroic mirror 523. The beam splitter 525 reflects the luminescence 800 of the laser plasma generated on the front surface 201 side of the wafer 200 by irradiation of the laser light 600 and guides it to the photographing unit 526.

[0118] The photographing unit 526 has a group lens not shown and a photographing element not shown. The group lens of the photographing unit 526 is an optical system in which an aberration correction lens and an imaging lens are arranged in that order. The photographing element of the photographing unit 526 is an element that photographs the image captured by the group lens, and as the preferred photographing element, the same photographing element as that used in the photographing unit 30 of the first embodiment is used.

[0119] The photographing unit 526 photographs the front surface 201 of the wafer 200 held on the holding surface 11 of the holding table 10, the division intended line 202 of the wafer 200 held by the holding table 10 before laser processing, and the laser processing groove 700 that is the processing trace of the wafer 200 after laser processing, in the same manner as the photographing unit 30 of the first embodiment. The photographing region of the photographing unit 526 moves in conjunction with the irradiation position of the laser light 600 based on the laser processing unit 520.

[0120] In the case where the photographing unit 526 photographs while irradiating the laser light 600 oscillated by the laser oscillation unit 521 and the stroboscopic light 650 emitted from the stroboscopic light irradiation unit 524, the photographing unit 526 photographs not only the front surface 201 of the wafer 200 but also the luminescence 800 of the laser plasma generated by irradiation of the laser light 600. The photographing unit 526 photographs the front surface 201 of the wafer 200 and the luminescence 800 of the laser plasma in a prescribed region during laser processing, obtains an image for performing so-called kerf walkthrough that judges the quality of laser processing, and outputs the obtained image to the control unit 60.

[0121] The inspection unit 40 is a functional unit that, based on the image obtained by taking a picture of the predetermined dividing line 202 during laser processing, inspects the laser processing groove 700 formed by the laser processing unit 520 as a processing mark and the emission of laser plasma 800 generated during laser processing, and inspects the quality of the laser processing according to the prescribed inspection items.

[0122] The wafer processing method of the second embodiment is a modification of the wafer processing method of the first embodiment, except that processing step ST16 and processing groove evaluation step ST17 are changed.

[0123] like Figure 15 As shown, in processing step ST16 of the wafer processing method of the second embodiment, the control unit 60 irradiates the front surface 201 of the wafer 200 with laser 600 in the same holding state as in the implementation of processing step ST16 of the first embodiment, using the laser processing unit 520. In processing step ST16 of the second embodiment, the control unit 60, while irradiated with laser 600, then uses the X-axis movement unit 71, Y-axis movement unit 72, and Z-axis movement unit 73 to perform processing feed, indexing feed, and cutting feed on the holding stage 10 or based on the irradiation position of the laser 600 by the laser processing unit 520, thereby performing laser processing from the front surface 201 side of the wafer 200 along the predetermined dividing line 202. In processing step ST16, through this laser processing, a laser processing groove 700 is formed on the front surface 201 side of the wafer 200 along the predetermined dividing line 202.

[0124] In the wafer processing method of the second embodiment, the processing groove evaluation step ST17 is performed in parallel with the processing step ST16, that is, it is implemented during laser processing. The processing groove evaluation step ST17 of the second embodiment is a step to determine the quality of the processing by taking pictures of the evaluation areas 210 and 212 and the light emission 800 of the laser plasma generated by the irradiation of the laser 600 during the processing of the evaluation areas 210 and 212.

[0125] Similar to the first embodiment, an inspection screen 900 in any evaluation area 212 is shown to illustrate an example of the processing trench evaluation step ST17 in the wafer processing method of the second embodiment. For example... Figure 16 As shown, the inspection screen 900 captures the predetermined dividing line 202 in the evaluation area 212, the formed laser processing tank 700, and the emission of laser plasma 800. The emission of laser plasma 800 is captured at the front end of the laser processing tank 700.

[0126] like Figure 16As shown, the check screen 900 shows a state in which the laser-processed groove 700 does not fall within the width 202-1 of the division predetermined line 202, the center line 702 of the laser-processed groove 700 has a large offset 703 in the width direction with respect to the center line 202-2 of the division predetermined line 202, and the position of the edge of the laser-processed groove 700 deviates from the threshold value. In addition, the check screen 900 shows a state in which the width 701 of the laser-processed groove 700 is not too thin, and no edge collapse is generated, and thus the edge collapse size is naturally not greater than the threshold value. Thus, in the processing groove evaluation step ST17, the control unit 60 determines that the evaluation region 212 is not qualified, that is, inferior, with respect to the check item for which a part of the laser-processed groove 700 is set, by the check section 40.

[0127] The wafer processing method of the second embodiment has the above structure, and thus, instead of the so-called kerf inspection, the so-called kerf tour is implemented in the wafer processing method of the first embodiment, but has the same evaluation region setting step ST13 and pattern region detection step ST14 as the wafer processing method of the first embodiment, and thus, has the same functional effects as the wafer processing method of the first embodiment. That is, the wafer processing method of the second embodiment has the functional effects that the trouble of the work of registering the position of the metal pattern 208 such as the TEG, which does not exist, for implementing the so-called kerf tour for evaluating the quality of the laser-processed groove 700, can be reduced. In addition, the wafer processing method of the second embodiment can more reliably avoid the metal pattern 208 such as the TEG and implement the kerf tour than in the past, and thus, can stabilize the kerf tour.

[0128] As with the modification example that can be applied to the wafer processing method of the first embodiment, the wafer processing method of the second embodiment can also implement a modification example in which the implementation order of the evaluation region setting step ST13 and the pattern region detection step ST14 are exchanged. In the wafer processing method of this modification example of the second embodiment, the pattern region detection step ST14 is implemented, and a part of the region in the pattern region in which the metal pattern 208 is not formed, as with the second embodiment, is set as the evaluation region 210 for evaluating the quality of the laser-processed groove 700 as the processing groove, by the evaluation region setting step ST13 implemented later.

[0129] In addition, the present application is not limited to the above-described embodiments. That is, various modifications can be made and implemented within the scope of the gist of the present application.

Claims

1. A wafer processing method, the wafer being periodically formed with a plurality of identical pattern regions on a front surface, the pattern region including a plurality of division lines crossing each other and a device region divided by the plurality of division lines, characterized by comprising: a holding step of holding a back surface side of the wafer by a holding stage; a photographing step of photographing a plurality of portions of the front surface of the wafer while relatively moving the holding stage and a photographing unit; a pattern region detecting step of detecting a period and position information of an image appearing substantially the same in the photographed images, and detecting the pattern region corresponding to one period; an evaluation region setting step of detecting a position where a metal pattern is not formed on the division line and setting as an evaluation region for evaluating a quality of a processing groove; an evaluation region developing step of recording the position of the evaluation region in the pattern region, and determining a reference pattern region including a reference coordinate of the evaluation region set by the evaluation region setting step, and developing the evaluation region at the same portion of a different pattern region with reference to the reference pattern region; a processing step of processing the wafer; and a processing groove evaluating step of photographing the evaluation region in at least two or more of the pattern regions, and determining a quality by photographing the processing groove.

2. A wafer processing method, the wafer being periodically formed with a plurality of identical pattern regions on a front surface, the pattern region including a plurality of division lines crossing each other and a device region divided by the plurality of division lines, characterized by comprising: a holding step of holding a back surface side of the wafer by a holding stage; a photographing step of photographing a plurality of portions of the front surface of the wafer while relatively moving the holding stage and a photographing unit; a pattern region detecting step of detecting a period and position information of an image appearing substantially the same in the photographed images, and detecting the pattern region corresponding to one period; an evaluation region setting step of detecting a position where a metal pattern is not formed on the division line and setting as an evaluation region for evaluating a quality of a processing groove; an evaluation region developing step of recording the position of the evaluation region in the pattern region, and determining a reference pattern region including a reference coordinate of the evaluation region set by the evaluation region setting step, and developing the evaluation region at the same portion of a different pattern region with reference to the reference pattern region; a processing step of processing the wafer by irradiating a laser beam; and a processing groove evaluating step of photographing the evaluation region and luminescence generated by irradiation of the laser beam in processing of the evaluation region, and determining a quality of a processing condition.

3. The wafer processing method according to claim 1 or 2, characterized in that: the plurality of division lines are formed in a first direction and a second direction crossing the first direction, and the pattern region detecting step is performed in both the first direction and the second direction. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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