TW202008439A - Alignment method in response to specifying a predetermined division line for the wafer and registering the target image in a processing device - Google Patents

Abstract

The invention relates to quickly finding an alignment mark when specifying a predetermined division line. An alignment method of the present invention is to image a wafer (W) with an imaging means (51) in which a device (D) is formed in a region divided by a first predetermined division line (S1) and a second predetermined division line (S2). The invention further includes detecting an alignment mark (MA) and an alignment method specifying the first predetermined division line (S1) and the second predetermined division line (S2). The alignment method includes:an image means (51) that registers a target image (GT) containing an alignment mark (MA) that is smaller than an imaging area (510) of the imaging means (51) as it is smaller than the region; the wafer (W) held on the suction platform (30) is combined with at least two horizontally-oriented photographic images taken by the imaging means (51) to form a combined image, and whenever a combined image is formed, the confirmation process for pattern matching is performed in the presence or absence of target image; and after the target image (GT) being detected, the first predetermined division line (S1) and the second predetermined division line (S2) are specified by the alignment mark (MA) in the target image (GT).

Description

Alignment method

The present invention relates to an alignment method of a predetermined division line of a specific wafer.

Carrying out a cutting process in which a wafer with elements formed in a region divided by a planned dividing line is cut into the cutting blade along the planned dividing line, or a machining groove is formed by irradiating laser light along the planned dividing line During laser processing, the device must recognize the planned dividing line.

The same circuit pattern is formed on the element surface of the wafer. Next, one of the circuit patterns having a characteristic shape is set as a macroscopic alignment mark. In addition, at a position away from the macroscopic alignment mark by a predetermined distance in a predetermined direction, a microscopic alignment mark smaller than the macroscopic alignment mark is set. Next, the planned dividing line is set at a position at a predetermined distance from the micro alignment mark in a predetermined direction.

The processing apparatus is in the macroscopic alignment, after finding the macroscopic alignment mark of the wafer held on the chuck platform, using the macroscopic alignment mark, the X axis of the predetermined line to be divided into the horizontal plane as the 1 axis The directions are roughly parallel but roughly parallel to each other (see, for example, Patent Document 1). Next, confirm the micro-alignment mark located at a predetermined distance from the macroscopic alignment mark in a predetermined direction, and use this micro-alignment mark to align the planned dividing line parallel to the X-axis direction with high accuracy High-precision θ matching. After that, a predetermined dividing line at a predetermined distance from the microscopic alignment mark is recognized. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2007-088028

(Problems to be solved by the invention)

In preparation for macroscopic alignment, the macroscopic alignment mark is imaged with an imaging means having an imaging area smaller than the area divided by the planned dividing line (that is, an imaging area smaller than the element size), and , The target image centered on the macroscopic alignment mark smaller than the imaging area is registered in the processing device.

In macroscopic alignment, whether or not there is a pattern matching of the target material image in the image captured by the imaging means of the wafer that has been newly attracted and held by the chuck platform is processed by the image capturing means. That is, for example, the target image is moved by 1 pixel each in the captured image to perform pattern matching. Next, if there is no target image in the captured image, the pixels of the target image are overlapped, and the position adjacent to the previous captured position is captured to form a new captured image. Within the new captured image, the target image is performed Match the pattern and find the macroscopic alignment mark.

As shown above, until the macroscopic alignment mark is found, the movement of the imaging position (specifically, the spiral movement on the wafer at the imaging position), and the use of the imaging by the movement of the imaging position The pattern matching of the target image in the new video image is repeated until the cumulative area of each video image captured by overlapping pixel portions becomes at least the same area as the area divided by the planned dividing line. The discovery sequence of macroscopic alignment marks performed by the conventional technique shown above is called a spiral search.

In the spiral search, while overlapping the pixels of the target image, the imaging area caused by the imaging method is widened. Therefore, if the target image is large (that is, the macroscopic alignment mark is large), the imaging method is moved The amount of movement to a position adjacent to the previous imaging position is reduced. The reason for overlapping the pixel portions of the target image is based on the reason that if only a part of the target image is mapped on the captured image, the entire image is not overlooked. Therefore, the distance of the portion of the target image is subtracted from the size of the entire image to move the imaging means to a position adjacent to the previous imaging position. Therefore, if the target image is large, the amount of movement in the imaging area will decrease, so The imaging position must be moved in a spiral shape for many times to perform many times of imaging, which causes a problem that it takes time to find the macroscopic alignment mark.

Specifically, for example, if the imaging area of the imaging means is 512×480 pixels, if the size of the macroscopic alignment mark is small, and the target image is 16×18 pixels, with the spiral movement of the imaging area of the imaging means The number of times of imaging may be, for example, a maximum of 6 times. On the other hand, if the size of the macroscopic alignment mark is large and the target image is 250×250 pixels, the number of imagings accompanying the spiral movement of the imaging area of the imaging means is, for example, up to 25.

Therefore, in the alignment method of a predetermined dividing line of a specific wafer, there is a problem of quickly finding an alignment mark (macroscopic alignment mark) to shorten the alignment time. (Means to solve the problem)

The present invention for solving the above-mentioned problems is an alignment method which is divided by a first planned dividing line set on the surface and a second planned dividing line crossing the first planned dividing line The wafer where the element is formed is held on the chuck platform, and the wafer held on the chuck platform is imaged by an imaging means to detect the alignment marks arranged in the area, and to specify the first planned dividing line and the The alignment method of the second predetermined dividing line includes: a registration process in which the imaging area of the imaging means is smaller than the area, and a target image including an alignment mark in an area smaller than the imaging area is registered; the confirmation process, It is that the wafers newly held on the chuck platform are combined with at least two camera portraits in the horizontal direction after being photographed by the camera means to form a combined portrait, and whenever the combined portrait is formed, there will be or The pattern matching is performed without the target image for confirmation; and the specific process is that if the target image is detected in the verification process, the first planned dividing line is specified by the alignment mark in the target image And the second planned dividing line. (Effect of invention)

The alignment method of the present invention is to implement the combination of at least two horizontally captured images of the wafer newly held on the chuck platform after being captured by the camera means to form a combined portrait, and whenever a combined portrait is formed, it will be in the combined portrait The confirmation process of confirming the pattern matching with or without the target image is performed, so that when the alignment mark of the new wafer to be processed is found, it is not necessary to perform a spiral search by conventional methods. In other words, it is not necessary to overlap the image area of the image capturing means with the pixel portion of the target image as is conventionally used and to move the image in a spiral shape for many times, and it is not necessary to capture each image of the image captured by the overlapping pixel portion To perform pattern matching of the target image. Therefore, the alignment mark (macroscopic alignment mark) can be quickly found, and the alignment time is shortened.

The cutting device 1 shown in FIG. 1 is a device that performs cutting by rotating and cutting the cutting blade 63 included in the cutting means 6 on the wafer W, which is a plate-shaped workpiece held on the chuck table 30.

The base 10 of the cutting device 1 is provided with cutting and feeding means 11 for reciprocating the chuck table 30 in the cutting and feeding direction (X-axis direction). The cutting feed means 11 is composed of: a ball screw 110 having an axis in the X-axis direction; a pair of guide rails 111 arranged parallel to the ball screw 110; a motor 112 that rotates the ball screw 110; and an internal screw The cap is screwed on the ball screw 110 and the bottom is slidingly connected to the movable plate 113 of the guide rail 111. Next, when the motor 112 rotates the ball screw 110, the movable plate 113 is guided by the guide rail 111 to move in the X-axis direction, and the chuck table 30 disposed on the movable plate 113 moves in the X-axis direction.

The chuck table 30 that holds the wafer W has, for example, a circular shape, and attracts and holds the wafer W on a horizontal holding surface 30a made of a porous member or the like. The chuck platform 30 is fixed to the movable plate 113 through the rotation means 31 disposed on the bottom surface side thereof. The rotation means 31 can support the chuck platform 30 and rotate the chuck platform 30 about the axis in the Z-axis direction. A plurality of clamps 32 that sandwich and fix the ring-shaped frame F are arranged at equal intervals in the circumferential direction around the chuck table 30.

On the rear side (-X direction side) of the base 10, a gate-shaped pillar 14 is erected so as to straddle the cutting feed means 11. Index feeding means 12 for reciprocating the cutting means 6 in the Y-axis direction are arranged in front of the portal pillar 14. The indexing feed means 12 is composed of: a ball screw 120 having an axis in the Y-axis direction; a pair of guide rails 121 arranged parallel to the ball screw 120; a motor 122 that rotates the ball screw 120; and internal The nut is screwed to the ball screw 120 and the side is slidingly connected to the movable plate 123 of the guide rail 121. Next, when the motor 122 rotates the ball screw 120, the movable plate 123 is guided by the guide rail 121 and moves in the Y-axis direction, and the cutting means 6 disposed on the movable plate 123 through the cutting feed means 16 The index feed is performed in the Y-axis direction.

The movable plate 123 is provided with cutting feed means 16 for reciprocating the cutting means 6 in the Z-axis direction (vertical direction) orthogonal to the holding surface 30 a of the chuck table 30. The plunge feed means 16 is composed of: a ball screw 160 having an axis in the Z-axis direction; a pair of guide rails 161 arranged parallel to the ball screw 160; a motor 162 that rotates the ball screw 160; and an internal screw The cap is screwed to the ball screw 160 and the side is slidingly connected to the support member 163 of the guide rail 161. Next, when the motor 162 rotates the ball screw 160, the support member 163 is guided by the guide rail 161 and moves in the Z-axis direction, and the cutting means 6 supported by the support member 163 is cut in and fed in the Z-axis direction.

The cutting means 6 includes: a rotating shaft 60 whose axis direction is the Y-axis direction; a case 61 that is fixed to the lower end of the support member 163 and rotatably supports the rotating shaft 60; and a motor (not shown) that rotates the rotating shaft 60; And the ring-shaped cutting blade 63 mounted on the rotating shaft 60 drives the rotating shaft 60 to rotate with a motor (not shown), and the cutting blade 63 also rotates at a high speed.

For example, macroscopic imaging means 51 for imaging the wafer W at a low magnification and microscopic imaging means 52 for imaging the wafer W at a high magnification are provided on the side surface of the housing 61 of the cutting means 6. The macroscopic imaging means 51 is composed of, for example, an imaging element (not shown), a low-magnification objective lens, and illumination that irradiates light to the wafer W sucked and held on the chuck table 30. The microscopic imaging means 52 is composed of, for example, an imaging element (not shown), a high-magnification objective lens, and illumination that irradiates light to the wafer W sucked and held on the chuck table 30. The macroscopic imaging means 51 and the microscopic imaging means 52 are linked to the cutting means 6 and move in the Y-axis direction and the Z-axis direction. For example, the magnification of the high-magnification objective lens is 10 times the magnification of the low-magnification objective lens, and one pixel in the image captured by the macroscopic imaging means 51 is 10 μm.

The cutting device 1 includes, for example, control means 9 that controls the entire device. The control means 9 is connected to the cutting feed means 11, the index feed means 12, the cutting feed means 16, the rotation means 31, etc. through wiring not shown. Under the control of the control means 9, the control means The cutting feed action of the chuck table 30 by the cutting feed means 11 in the X axis direction, the index feed amount of the cutting means 6 by the index feed means 12 in the Y axis direction, and the feed by cutting The cutting feed 6 is a cutting feed in the Z-axis direction of the cutting means 6, and the rotating operation of the chuck table 30 by the rotating means 31.

Hereinafter, each process of the alignment method of the present invention when the first planned dividing line S1 and the second planned dividing line S2 of the wafer W that is subjected to the cutting process using the cutting device 1 shown in FIG. 1 are specified will be described.

(1) Login project The wafer W shown in FIG. 1 is, for example, a circular silicon semiconductor wafer, and the surface Wa of the wafer W is formed with elements D each in a grid-like area divided by a predetermined dividing line. A dicing tape T having a larger diameter than the wafer W is attached to the back surface Wb of the wafer W. A ring frame F having a circular opening is attached to the outer peripheral area of the adhesive surface of the dicing tape T, and the wafer W is supported by the ring frame F through the dicing tape T, and is formed to be able to pass through the ring frame The processing status of F. Each planned dividing line extending in the same direction (for example, the X-axis direction in FIG. 1) set on the surface Wa of the wafer W is set as the first planned dividing line S1. On the other hand, Each planned dividing line extending on a direction perpendicular to the first planned dividing line S1 (the Y-axis direction orthogonal to the X-axis direction in the horizontal plane) on the Wa is referred to as a second planned dividing line S2.

In the registration process, first, by the chuck table 30 shown in FIG. 1, the wafer W is attracted and held with the surface Wa facing upward. Next, the chuck table 30 that attracts and holds the wafer W is moved in the X-axis direction by the cutting and feeding means 11. In addition, the macroscopic imaging means 51 is moved in the Y-axis direction by the index feed means 12, and is formed in a state where the approximate center of the wafer W is located directly under the objective lens of the macroscopic imaging means 51. Next, the surface Wa of the wafer W is imaged by the macroscopic imaging means 51 to form an imaged image.

The size of the imaging area 510 of the macroscopic imaging means 51 is smaller than the area divided by the first planned dividing line S1 and the second planned dividing line S2, that is, the size of the element D.

Next, the operator selects a pattern having a characteristic shape among the circuit patterns mapped on the surface of the element D of the wafer W of the captured image as the macroscopic alignment mark MA. The macroscopic alignment mark MA is formed one by one for the plural elements D, for example, at the corner of the element D (the lower left corner in FIG. 2). Among them, the macroscopic alignment mark MA is preferably a simple shape like a cross shape shown in FIG. 2 or a simple shape like a circle or a square. In addition, the macroscopic alignment mark may not be part of the circuit pattern.

Next, a characteristic part of the element or wiring formed on the surface of the element D and located at a predetermined distance from the macroscopic alignment mark MA in a predetermined direction is selected by the operator as much smaller than the macroscopic alignment mark MA Microscopic alignment mark MB. The micro alignment marks MB are formed at the same position for each of the plural elements D, for example, the corner portion of the element D (the lower right corner in FIG. 2). Along with the selection of the microscopic alignment mark MB, the distance and direction from the macroscopic alignment mark MA to the microscopic alignment mark MB are memorized in the memory section 91. That is, by counting the number of pixels and the like, it is memorized that there is a microscopic alignment mark MB at a position away from the macroscopic alignment mark MA by the distance Lx1 in the X-axis direction and at a distance Ly1 in the Y-axis direction. In addition, the memory unit 91 memorizes the distance Lx2 from the micro alignment mark MB to the center line of the center of the wide width passing through the second planned dividing line S2 and the wide width of the micro alignment mark MB to the first line passing through the first dividing line S1 The distance from the centerline of the center is Ly2.

In addition, by the operator, the macroscopic alignment mark MA is registered in the rectangular area shown by the two-dot chain line of the imaging area 510 of the macroscopic imaging means 51 in the memory portion 91 of the control means 9. That is, the target image GT including the entire macroscopic alignment mark MA is stored in the memory unit 91.

This registration process may also be referred to as a teaching process (Teaching process) for the cutting device 1 shown in FIG. 1. If multiple wafers W of the same type are cut, if the first wafer W is cut This is done once, and does not need to be performed after the second wafer W is sucked and held again by the chuck table 30.

However, the registration process is not limited to this embodiment. For example, there may be a case where a plurality of device materials listed in a plurality of processing conditions corresponding to each type of wafer to be processed are stored in the memory unit 91 in advance. The processing conditions refer to various settings that will be used to perform appropriate cutting processing on the wafer for each type of wafer to be processed. The various settings refer to the data except for the cutting shown in FIG. 1 In addition to the cutting feed speed of the chuck table 30 for holding the wafer by the feed means 11, the index feed amount of the cutting means 6 by the index feed means 12, etc. Information on various types of macroscopic alignment marks or microscopic alignment marks. Therefore, it can also be formed that the operator selects the appropriate processing conditions of the wafer W shown in FIG. 1 from the component data, whereby the area indicated by the two-dot chain line is smaller than the imaging area 510 of the macroscopic imaging means 51, Those who registered the target image GT containing the entire macro mark MA. At this time, the wafer W by the macroscopic imaging means 51 may not be imaged in this registration process.

(2) Confirm the project With the chuck table 30 shown in FIG. 1, the new wafer W for cutting is attracted and held with the surface Wa facing upward. The chuck table 30 that attracts and holds the new wafer W shown in FIG. 1 is moved in the X-axis direction by the cutting and feeding means 11. In addition, the macroscopic imaging means 51 is moved in the Y-axis direction by the index feed means 12. Next, the surface Wa of the wafer W is formed directly below the objective lens of the macroscopic imaging means 51. If the imaging position of the surface Wa of the wafer W by the macroscopic imaging means 51 is an area where the element D is formed, it is not limited to a specific position.

In this state, the surface Wa of the wafer W is imaged by the macroscopic imaging means 51 to form the imaging image G1 shown in FIG. 3. The size of the captured image G1 is the same as the size of the imaging area 510 of the macroscopic imaging means 51 shown in FIG. 2, and therefore is smaller than the size of the element D. The captured image G1 is stored in the memory unit 91 of the control means 9.

After the imaging image G1 is formed, for example, the chuck table 30 holding the wafer W is moved by the cutting and feeding means 11 shown in FIG. 1. That is, the macroscopic imaging means 51 in a state where the relative movement is stopped attracts and holds the chuck table 30 holding the wafer W relatively, for example, by a predetermined distance in the +X direction. This moving distance of the chuck table 30 has the same value as the length in the X-axis direction of the imaging area 510 of the macroscopic imaging means 51 shown in FIG. 2, for example.

The chuck platform 30 moves as described above, thereby forming a state where the imaging area 510 of the macroscopic imaging means 51 is located adjacent to the X-axis direction of the imaging position when the imaging image G1 is imaged. Next, the surface Wa of the wafer W is imaged by the macroscopic imaging means 51 to form the imaging image G2 shown in FIG. 4 in which the imaging image G1 is arranged horizontally in the X-axis direction. The captured image G2 is stored in the memory unit 91 of the control means 9.

For example, the control means 9 shown in FIG. 1 includes a combined image forming unit 92 that combines the captured images formed by the macroscopic imaging means 51 and forms a combined image. The combined image forming unit 92 displays, for example, a combined image GA shown in FIG. 4 that combines the captured image G1 stored in the memory unit 91 with the newly captured captured image G2 on a virtual screen of a predetermined resolution.

Next, the pattern matching unit 93 included in the control means 9 shown in FIG. 1 performs pattern matching with or without the target image GT in the combined image GA. That is, the pattern matching unit 93 superimposes the target image GT on the combined image GA displayed on the virtual screen of a predetermined resolution, for example, and sets the target image GT on the X axis on the combined image GA, for example, in 1 pixel units Moving in the direction or the Y-axis direction, the region having the highest correlation with the target image GT in the combined image GA is detected as the region matching the target image GT.

As shown in FIG. 4, the pattern matching unit 93 cannot detect the area matching the target image GT in the combined image GA. Therefore, the surface Wa of the wafer W is imaged by the macroscopic imaging means 51. That is, with the index feed means 12 shown in FIG. 1, the macroscopic imaging means 51 relatively moves the predetermined distance in the +Y direction, for example, with respect to the chuck platform 30 in a state where the relative movement is stopped. This moving distance of the macroscopic imaging means 51 has the same value as the length of the imaging area 510 of the macroscopic imaging means 51 in the Y-axis direction, for example.

The macroscopic imaging means 51 moves as described above, whereby the imaging area 510 of the macroscopic imaging means 51 is positioned adjacent to the Y-axis direction of the imaging position when imaging the captured image G2. Next, the surface Wa of the wafer W is imaged by the macroscopic imaging means 51 to form the imaging image G3 shown in FIG. 5 in which the imaging image G2 is arranged horizontally in the Y-axis direction. The captured image G3 is stored in the memory unit 91 of the control device 9.

The combined image forming unit 92 displays the combined image GA combining the camera image G1 and the camera image G2 stored in the memory unit 91 on the virtual screen with a predetermined resolution, and the camera image G3 combined with the newly captured camera image G3 . Next, the pattern matching unit 93 superimposes the target image GT on the combined image GB, and moves the target image GT in the X-axis direction or the Y-axis direction in units of 1 pixel on the combined image GB to detect the combined image GB The target portrait GT matches the area.

As shown in FIG. 5, the pattern matching unit 93 cannot detect the region matching the target image GT in the combined image GB, and therefore, the surface Wa of the wafer W is imaged by the macroscopic imaging means 51. That is, in the macroscopic imaging means 51 in a state where the relative movement is stopped, the chuck stage 30 that attracts and holds the wafer W is relatively the same as the length in the X-axis direction of the imaging area 510 of the macroscopic imaging means 51 in the -X direction, for example. The distance is moved so that the imaging area 510 is located adjacent to the X-axis direction of the imaging position when imaging the captured image G3. Next, the surface Wa of the wafer W is imaged by the macroscopic imaging means 51, and the imaging image G4 shown in FIG. 6 formed on the imaging image G3 in the X-axis direction is stored in the memory unit 91. Whereas, as shown in FIGS. 4 to 6, the imaging of the wafer W by the macroscopic imaging means 51 is viewed from above, for example, on the wafer W, the imaging area 510 is drawn in a clockwise spiral trajectory get on.

As shown in FIG. 6, the combined image forming unit 92 displays a combined image GC that combines the combined image GB stored in the memory unit 91 and the newly captured image G4 on a virtual screen with a predetermined resolution. Next, the pattern matching unit 93 superimposes the target image GT on the combined image GC, and moves the target image GT in the X-axis direction or the Y-axis direction in units of 1 pixel on the combined image GC to detect the combined image GC. The target image GT matches the area to find the macroscopic alignment mark MA.

As described above, the alignment method of the present invention is implemented by combining wafers W newly held on the chuck table 30 with at least two horizontally captured imaging images captured by the macroscopic imaging means 51 to form combined images GA to GC. In addition, every time when each of the combined images GA to GC is formed, a confirmation process is performed to confirm the pattern matching in the combined images GA to GC with or without the target image GT, thereby finding the macro view of the new wafer W to be processed When aligning the mark MA, it is not necessary to perform the spiral search conventionally. That is, it is not necessary to superimpose the imaging area 510 of the macroscopic imaging means 51 to overlap the pixels of the target image GT and to perform imaging in a spiral motion, and there is no need to image after repeating the pixels. For each camera image, pattern matching of the target image GT is performed. Therefore, the macroscopic alignment mark MA can be found more than before, and the alignment time can be shortened.

Among them, in the spiral search performed in the past, the macroscopic imaging means 51 is used to form an imaged image, and the pattern matching using the imaged image and the target image GT is performed. If the target image GT cannot be detected in the imaged image, then , The formed captured image is erased by the memory unit 91 and the next captured image is taken. On the other hand, in the alignment method of the present invention, since the combined images GA to GC are formed, the capacity of the image data stored in the memory unit 91 increases. However, the number of times of imaging of the wafer W by the macroscopic imaging means 51 is greatly reduced compared to conventional ones. Therefore, relatively speaking, the operation load of the control means 9 of the cutting device 1 is reduced.

(3) Partition of the predetermined line As described above, the macroscopic alignment mark MA is found for two elements D located at positions separated from each other in the X-axis direction, for example. Next, from the found macroscopic alignment mark MA and microscopic alignment mark MB, the first planned dividing line S1 and the second planned dividing line S2 are specified.

First, for example, a thick θ-alignment in which the first planned dividing line S1 of the wafer W is aligned approximately parallel to the X-axis direction is performed. The coarse-theta matching system attracts and maintains crystals in such a way that the Y-axis coordinate positions of the macroscopic alignment marks MA of the two coarse-theta matching camera images (for example, the combined image G4 formed in the confirmation process) are substantially the same. The suction cup platform 30 shown in FIG. 1 of the circle W is angle-adjusted by the rotation means 31.

In addition, after the chuck table 30 is moved in the X-axis direction by several parts of the element D, the imaging by the macroscopic imaging means 51 is performed to form a coarse θ paired image that is mapped by the macroscopic alignment mark MA of a certain element D portrait. The Y-axis coordinate position of the macroscopic alignment mark MA with the previously used coarse θ paired camera image is substantially the same as the Y-axis coordinate position of the macroscopic alignment mark MA with the separately formed coarse θ paired camera image Mode, the suction cup platform 30 is angle-adjusted by the rotation means 31, the straight line connecting the macroscopic alignment mark MA at the position separated in the X-axis direction is approximately parallel to the X-axis direction, and the first planned dividing line S1 is formed as The rough θ alignment approximately parallel to the X-axis direction is completed.

Next, the cutting device 1 shown in FIG. 1 is formed in a state where imaging of the wafer W by the micro imaging device 52 can be performed. In addition, one macroscopic alignment mark MA (see FIG. 6) that can be found first is located in the center of the imaging area of the microscopic imaging means 52.

Under the control by the control means 9, by the cutting feed means 11, the chuck stage 30 that attracts and holds the wafer W takes the X-axis direction of the macroscopic alignment mark MA and the microscopic alignment mark MB shown in FIG. 2 The distance Lx1 (the distance Lx1 of the memory section 91) is moved, and by the index feed means 12, the microscopic imaging means 52 uses the macroscopic alignment mark MA and the microscopic alignment mark MB in the Y-axis direction Ly1 (the distance Ly1 memorized in the memory section 91) is moved. After that, the surface Wa of the wafer W is imaged by the micro imaging means 52 to form a high-precision θ-pair imaging image mapped by the micro alignment marks MB.

The high-precision θ-alignment system uses, for example, high-precision θ-alignment imaging using the micro-alignment marks MB of the two elements D adjacent to the first planned dividing line S1 and located at positions separated from each other in the X-axis direction. Portrait. Next, until the deviation of the two high-precision θ to the Y-axis coordinate position of each micro-alignment mark MB of the combined camera image becomes within the allowable value, the chuck table 30 is angle-adjusted by the rotation means 31, and the θ with high accuracy The match is completed.

In addition, the chuck table 30 shown in FIG. 1 moves in the X-axis direction, for example, the center of the surface Wa of the wafer W is positioned in the imaging area of the microscopic imaging means 52, and the microscopic imaging means 52 forms an imaging portrait to recognize the imaging The micro alignment mark MB in the portrait. Next, it is determined whether the deviation of the Y-axis coordinate position of the micro-alignment mark MB is within the allowable value. If it is outside the allowable value, the micro-alignment mark MB is shifted to the allowable value by the Y-axis coordinate position. The imaging means 52 is appropriately moved in the Y-axis direction by the index feed means 12.

After the Y-axis coordinate position of the micro-alignment mark MB is shifted to within the allowable value, the indexing feed means 12 moves from the micro-alignment mark MB to the center of the first division line S1 in the width direction shown in FIG. 2 The line distance Ly2 moves the microscopic imaging device 52 in the Y-axis direction, thereby superimposing the reference line (line of sight) of the microscopic imaging device 52 on the first planned dividing line S1. Next, the coordinate position of the aiming line in the Y-axis direction when the aiming line overlaps the first planned dividing line S1 is stored in the memory of the control means 9 as the position where the cutting means 6 is positioned when the cutting blade 63 actually cuts the wafer W部91.

As described above, after the coordinate position in the Y-axis direction when actually cutting the first planned dividing line S1 is stored in the memory section 91, the chuck table 30 is accurately rotated by 90 degrees by the rotation means 31, and the second wafer W is processed. The planned dividing line S2 is aligned with the X axis direction in parallel with high accuracy. Then, the Y-axis coordinate position where the cutting means 6 is positioned when the second scheduled dividing line S2 is actually cut is detected and stored in the memory section 91 ( Perform line-of-sight alignment). As a result, in the cutting device 1, the first planned dividing line S1 and the second planned dividing line S2 of the new wafer W are specified.

(4) Wafer cutting Next, the cutting device 1 shown in FIG. 1 performs cutting processing on the new wafer W attracted and held on the chuck table 30. For example, first, the cutting means 6 is positioned by the index feed means 12 at the Y-axis coordinate position when the first cutting planned line S1 is actually cut in the memory section 91 of the control means 9. In addition, under the control by the control means 9, the cutting feed means 16 causes the cutting means 6 to descend in the -Z direction, and the cutting means 6 is positioned at a predetermined cutting feed position. In addition, the cutting feed means 11 moves the chuck table 30 holding the wafer W toward the cutting means 6 and performs cutting feed at a predetermined cutting feed speed.

A motor (not shown) rotates the rotating shaft 60 of the cutting means 6 at high speed, whereby the cutting blade 63 fixed to the rotating shaft 60 rotates while rotating the rotating shaft 60 and cuts into the wafer W to cut the first division plan.线S1.

When the chuck table 30 travels to a predetermined position in the X-axis direction of the first dividing line S1 after the cutting blade 63 cuts, the cutting feed means 16 raises the cutting means 6 to separate the cutting blade 63 from the wafer W, and then, cuts The feed means 11 returns the chuck table 30 to the cutting feed start position. Next, the indexing feed means 12 moves the cutting means 6 in the Y-axis direction by a predetermined indexing feed amount, thereby relative to the first planned dividing line S1 located adjacent to the cut first planned dividing line S1, The cutter 63 is positioned. Next, the cutting process is performed as before. Hereinafter, by performing the same cutting in sequence, all the first planned dividing lines S1 are cut. In addition, after rotating the chuck table 30 by 90 degrees, the second planned dividing line S2 is cut, whereby all the planned dividing lines of the wafer W are cut horizontally and vertically.

Each project of the alignment method of the present invention is not limited to the above-mentioned embodiment, and can be implemented in various forms within the scope of its technical idea, needless to say. In addition, the constituent elements of the cutting device 1 illustrated in the drawings are not limited thereto, and can be appropriately changed within the range in which the effects of the present invention can be exerted. The alignment method of the present invention can also be implemented in a laser processing apparatus that performs desired processing on the wafer W by laser irradiation.

D‧‧‧component F‧‧‧ring frame G1~G4‧‧‧Camera portrait GA, GB, GC‧‧‧Combined portrait GT‧‧‧ target material portrait Lx2, Ly2‧‧‧Distance MA‧‧‧ Macroscopic alignment mark MB‧‧‧Micro alignment mark S1‧‧‧The first division plan line S2‧‧‧Second scheduled dividing line T‧‧‧cutting tape W‧‧‧ Wafer Wa‧‧‧wafer surface Wb‧‧‧wafer back 1‧‧‧Cutting device 10‧‧‧Abutment 11‧‧‧Cutting feed method 12‧‧‧Dividing feed means 14‧‧‧Gate pillar 16‧‧‧cutting feed method 30‧‧‧Sucker platform 30a‧‧‧Keep noodles 31‧‧‧Rotation means 32‧‧‧Fixture 51‧‧‧Grand view camera 52‧‧‧Micro camera 510‧‧‧Camera area 6‧‧‧Cutting means 60‧‧‧rotation axis 61‧‧‧Housing 63‧‧‧Cutter 9‧‧‧Control 91‧‧‧ Memory Department 92‧‧‧Combined image forming department 93‧‧‧ Pattern Matching Department 110, 120, 160 ‧‧‧ ball screw 111, 121, 161‧‧‧rail 112, 122, 162 113, 123‧‧‧ movable plate 163‧‧‧Support component

FIG. 1 is a perspective view showing an example of a cutting device for cutting a wafer. FIG. 2 is an explanatory diagram for explaining the registration of a target image including an alignment mark in an area smaller than the imaging area. FIG. 3 is an explanatory diagram illustrating a captured image of a wafer held on a chuck platform by an imaging means. FIG. 4 is an explanatory diagram illustrating a situation in which two photographic images in a horizontal row are combined to form a combined image, and pattern matching and confirmation are performed with or without a target material image in the combined image. FIG. 5 is an explanatory diagram illustrating a situation in which three horizontally aligned photographed images are combined to form a combined image, and pattern matching and confirmation are performed with or without a target material image in the combined image. FIG. 6 is an explanatory diagram illustrating a situation in which four photographic images in a horizontal row are combined to form a combined image, and pattern matching and confirmation are performed with or without a target material image in the combined image.

D‧‧‧component

G1~G4‧‧‧Camera portrait

GC‧‧‧Combined portrait

GT‧‧‧ target material portrait

MA‧‧‧ Macroscopic alignment mark

MB‧‧‧Micro alignment mark

W‧‧‧ Wafer

Wa‧‧‧wafer surface

S1‧‧‧The first division plan line

S2‧‧‧Second scheduled dividing line

Claims (1)

An alignment method that holds a wafer in which an element is formed in an area partitioned by a first planned dividing line set on the surface and a second planned dividing line crossing the first planned dividing line On the chuck platform, the wafer held by the chuck platform is imaged by an imaging means, the alignment marks arranged in the area are detected, and the alignment method of the first planned dividing line and the second planned dividing line is specified , Which includes: The registration process, in which the imaging area of the imaging means is smaller than the area, and the target image including the alignment mark of the area smaller than the imaging area is registered; Confirm the project, which is to combine the wafers newly held on the chuck platform with the at least two camera images in the horizontal direction after being captured by the camera means to form a combined portrait, and whenever the combined portrait is formed, the combined portrait will be formed Confirm with or without the target image by pattern matching; and In the specific process, if the target portrait is detected in the confirmation process, the first planned division line and the second planned division line are specified by the alignment marks in the target portrait.

Images