JP2019174262A - Measuring method and processing method of bonded substrate and device used for the same - Google Patents

Abstract

In a bonded substrate, a center of a silicon wafer having a maximum outer diameter corresponding to an outer diameter of a glass substrate after bonding and a position of the maximum outer diameter thereof are obtained. A bonded substrate is formed by bonding a transparent second substrate to a first substrate via an adhesive. An image of the bonded substrate 100 placed on the rotary table 110 is taken, and a camera 120 disposed above the bonded substrate and side lighting disposed on a side portion of the bonded substrate at a position higher than the upper surface of the bonded substrate. A backlight unit 140 disposed below the bonded substrate; and a control unit for exclusively operating the side illumination unit and the backlight unit 140. By operating the side lighting means 130 and the backlight means 140 exclusively, the camera 120 captures two types of images having different contours of the bonded substrate 100. The control means obtains an overlapping portion of the first substrate and the second substrate, an inscribed circle and its center from the two types of captured images. [Selection diagram] FIG.

Description

  The present invention relates to a measurement method and a processing method of a bonded substrate in which a silicon substrate is bonded to a glass substrate, and an apparatus used therefor, and more particularly, a measurement method and a processing method of a bonded substrate that are suitable for use in a thinned wafer, and It is related with the apparatus used for them.

  However, with the progress of the Internet, it is required to make semiconductor devices or chips formed on a silicon wafer, such as various sensors, communication devices, and memories, thin and thin. As a result, for example, a wafer having a thickness of 100 μm is thinned to several tens of μm by back grinding or the like.

  As the wafer becomes thinner, the wafer becomes flared like paper, making normal wafer handling difficult. Therefore, a temporary bonded substrate that can be handled by temporarily bonding a supporting substrate having hardness and a certain degree of strength such as glass to the back surface of the wafer is used. The temporarily bonded wafer is thinned and peeled off from the support substrate after the process is completed, and is sent to the subsequent steps. This process is called TB / DB (temporary bonding / debonding). After the TB / DB, the thinned wafer as the target is cut and packaged according to the purpose. On the other hand, the glass substrate which is a support substrate may be used again to handle another wafer before thinning, in which case the glass substrate is returned to the temporary bonding step.

  When the glass substrate is used a plurality of times, the glass substrate serving as the support substrate is formed in a disc having a predetermined outer diameter, and the wafer to be bonded is a disc having a diameter slightly larger than that of the glass substrate. As a result, even if the wafer is attached eccentrically with respect to the glass substrate during temporary attachment, the diameter of the glass substrate can be reduced by removing the outer periphery of the wafer by grinding with a wafer chamfering machine on the basis of the glass substrate. A perfect circular wafer having a predetermined outer diameter is obtained.

  Patent Document 1 discloses a method for processing a bonded substrate in which a silicon substrate and a glass substrate are bonded together. This publication discloses a method for processing a bonded substrate, in which a resin layer that joins a first substrate made of a silicon substrate and a second substrate made of a glass substrate can be broken together with the two substrates without generating burrs. Is described.

  Further, Patent Document 2 discloses a semiconductor manufacturing method that can thin a wafer by a simple process without affecting the surface structure, and can manufacture a low-voltage and high-voltage device that can reuse the remaining wafer on the removed side. It is disclosed. In this publication, a WSS wafer is produced by bonding the surface of a device wafer to a glass support plate via an adhesive, and the wafer is cut parallel to the wafer surface with the WSS wafer sandwiched between suction chucks.

JP 2017-41472 A Japanese Patent Laid-Open No. 2006-46321 JP, 2006-130738, A

  When a silicon wafer substrate is temporarily bonded to a glass substrate in order to thin the wafer, even if the wafer is bonded using an automatic machine, there is always a misalignment between the silicon substrate and the glass substrate as viewed microscopically. If the amount of misalignment is within a range in which the outer diameter of the glass substrate is within the outer diameter of the wafer, only the wafer portion that protrudes from the outer diameter of the glass substrate may be removed with a wafer chamfering machine. However, in order to reduce the processing amount or grinding amount of the wafer and to reduce the processing time, the wafer removal amount may be reduced to make the outer diameter of the wafer closer to the outer diameter of the glass substrate. In that case, a slight misalignment between the wafer and the glass substrate may cause a portion where the glass substrate is located outside the wafer outer diameter.

  Further, the misalignment between the wafer and the glass substrate is greatly affected by the difference in diameter and material for each wafer, the adhesive used for bonding, bonding accuracy, and the like. The wafer chamfering machine removes such a shift between the wafer and the glass substrate generated in the bonding process and processes the wafer into a perfect circle. For this purpose, a reference processing center position is required. The measurement of the processing center position is desired to be performed in a non-contact manner to prevent wafer contamination.

  In order to obtain the wafer center, a method of detecting the outer periphery of the bonded substrate using a laser sensor has been conventionally performed. However, when a laser is applied to the outer periphery of the bonded substrate, the laser detector detects the reflection from the entire bonded substrate or only the reflection from the non-transmissive wafer substrate. If a portion located on the outer diameter side of the substrate is generated, the presence of the glass substrate is ignored. As a result, a measurement error occurs.

  On the other hand, Patent Document 1 describes processing a bonded substrate made of a silicon substrate and a glass substrate. Here, manufacturing a wafer in a perfect circle shape is one of the most important factors in the yield of manufactured chips, but in this publication, the bonded substrate is made into a perfect circle before the wafer thinning process. There is no disclosure about processing, and it is assumed that it is assumed that a wafer already manufactured in a perfect circle is used.

  Patent Document 2 describes that a wafer material is placed on a glass support plate corresponding to a glass substrate, and the wafer material is sliced to obtain a thinned wafer. However, this Patent Document 2 does not clearly show how to grasp the relative position between the glass support plate and the wafer and execute the subsequent processing based on the center of the wafer.

  The present invention has been made in view of the above-mentioned problems of the prior art, and the object thereof is the maximum corresponding to the outer diameter of the glass substrate after bonding in a bonded substrate in which a silicon wafer substrate is bonded to a laser transmissive glass substrate. The purpose is to determine the center of the outer diameter silicon wafer and its maximum outer diameter position. Another object of the present invention is to accurately determine the center of the silicon wafer and the maximum outer diameter position thereof in a non-contact manner even if the glass substrate sticks out of the silicon substrate.

  The present invention that achieves the above object is characterized in that in the method for measuring a bonded substrate formed by bonding a transparent second substrate to a first substrate on which a semiconductor element is formed via an adhesive means, A camera capable of placing the laminated substrate on a rotary table and measuring the outline of the bonded substrate above the bonded substrate is positioned on the side of the bonded substrate and higher than the upper surface of the bonded substrate. The side illumination means and the backlight means are provided below the bonded substrate, respectively, and the side illumination device and the backlight device are operated exclusively with each other, so that two kinds of images of the outline of the bonded substrate are obtained. , The edge of the overlapping portion of the first substrate and the second substrate is obtained from the two types of taken images, and the inscribed circle and its center are obtained from the obtained edge.

  In this feature, the first substrate is a silicon wafer substrate, the second substrate is a glass substrate, and the outer diameter of the first substrate before measurement is larger than the outer diameter of the second substrate. The side illumination means preferably includes diffusion means for diffusing light (diffuse irradiation is possible). Further, the edge of the overlapping portion is the end of the dark portion in the captured image when a dark portion line is further recognized outside the dark portion in the captured image in backlight illumination, and the edge of the dark portion in the captured image in backlight illumination. When only a bright part is recognized on the outside, it is preferable to use the inner line of two curves in the corresponding captured image in the side illumination.

  Another feature of the present invention that achieves the above object is that, after the above-described method for measuring a bonded substrate, based on the center of an inscribed circle obtained from the edge of the overlapping portion, the bonded substrate with the center as the center Is rotated from the center of the inscribed circle to the radial position by bringing a grindstone into contact with the outer peripheral portion thereof.

  Still another feature of the present invention that achieves the above object is a bonded substrate measuring apparatus formed by bonding a transparent second substrate to a first substrate on which a semiconductor element is formed via an adhesive means. A camera disposed above the bonded substrate for imaging the bonded substrate mounted on a rotary table; and a side portion of the bonded substrate that is positioned higher than the upper surface of the bonded substrate Side illumination means, backlight means arranged below the bonded substrate, and control means for operating the side illumination means and the backlight means exclusively of each other. By operating the means and the backlight means exclusively, the camera can take two different images of the outline of the bonded substrate. Ri, the control means obtains the first substrate and the overlapping portion of the edge of the second substrate from the two images captured is to obtain the center and the inscribed circle of the determined edge.

  In this feature, the first substrate is a silicon wafer substrate, the second substrate is a glass substrate, and the outer diameter of the first substrate before measurement is larger than the outer diameter of the second substrate. The side illumination means is preferably capable of diffusing irradiation, and the first and second substrates constituting the bonded substrate each have a chamfered periphery, and the camera operates the side illumination means. In this case, it is preferable that the reflected light from the chamfered portion is detected and the contour shape of the bonded substrate is imaged separately from other portions.

  According to the present invention, the outer peripheral portion of the bonded substrate is switched by switching between the side illumination that irradiates the chamfered outer peripheral surface of the silicon wafer substrate that constitutes the bonded substrate and the backlight illumination that illuminates the entire occupied portion of the bonded substrate. The center of the silicon wafer with the maximum outer diameter corresponding to the outer diameter of the glass substrate is bonded after the bonded substrate in which the silicon wafer substrate is bonded to the laser transmissive glass substrate. And the maximum outer diameter position can be easily obtained. In addition, the relative positional relationship between the glass substrate and the silicon wafer substrate can be determined from two types of imaging with different illuminations, and even if the glass substrate protrudes from the silicon substrate and is bonded, The center and its maximum outer diameter position can be obtained without contact.

It is a figure which shows a part of process of the bonded substrate board which concerns on this invention. It is a top view of one Example of the measurement and chamfering apparatus of the bonded substrate board concerning the present invention. It is a figure explaining the measuring method of the bonded substrate board concerning the present invention. It is a figure which shows an example of the measurement result of the bonded substrate which concerns on this invention. It is a figure explaining the principle of the measurement using side illumination. It is a figure explaining how to obtain the center and radius of a bonded substrate. It is a flowchart of the process of the bonded substrate board which concerns on this invention.

  Hereinafter, a method for measuring a bonded substrate and an apparatus used therefor according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic view illustrating processing of a bonded substrate 100 according to the present invention. The bonded substrate 100 includes a silicon wafer substrate 10 having a thickness of about 700 μm on which a semiconductor element pattern is formed, and a glass substrate 20 having a thickness of about 1 mm. Since the silicon wafer substrate 10 is thinned to about 50 μm in the subsequent steps, the glass substrate 20 serves as a strength support member for facilitating handling of the silicon wafer substrate 10 that has been thinned.

  In step (a), a silicon wafer substrate 10 and a glass substrate 20 on which semiconductor elements are formed are prepared, and in step (b), the silicon wafer substrate 10 is inverted (15) so that the surface on which the semiconductor elements are formed faces downward. On the other hand, an adhesive means 30 such as an adhesive is applied to the glass substrate 20. In step (c), these two substrates 10 and 20 are prepared at the bonding position, and both the substrates are bonded in step (d) using a not-shown bonding marker formed on each substrate 10 and 20 as a mark. A bonded substrate 100 is formed. This bonding is temporary bonding, and after the silicon wafer substrate 10 is subjected to predetermined processing including processing in subsequent steps, the glass substrate 20 and the silicon wafer substrate 10 are separated, and the glass substrate 20 is Returned to step (a) for reuse. Therefore, the bonding means 30 of the bonded substrate 100 has an adhesive force that can be separated without damaging both the substrates 10 and 20.

  In the bonding of the silicon wafer substrate 10 and the glass substrate 20, the bonding is performed with the center positions of the substrates 10 and 20 being misaligned to some extent. Accordingly, the outer diameter of the silicon wafer substrate 10 is configured to be slightly larger than the outer diameter of the glass substrate 20 and bonded together, and the outer edge portion of the silicon wafer substrate 10 protruding from the glass substrate 20 is removed by grinding with a grindstone or the like. . Here, in most cases, since the glass substrate 20 does not protrude from the silicon wafer substrate 10 and is bonded, the outer diameter of the glass substrate 20 becomes a predetermined predetermined outer diameter required for the silicon wafer substrate 10. Yes. In order to grind and remove with a grindstone or the like, in the step (e), the bonded substrate 100 is transported to the measuring device 110 provided with the measuring table 112.

  Although details of the measurement will be described later, the measurement apparatus 110 includes a rotatable measurement table 112 on which the bonded substrate 100 is mounted, a CCD camera 120 that can image the bonded substrate 100 mounted on the measurement table 112, A side illumination device 130 is disposed on the side of the bonded substrate 100 by irradiating the bonded substrate 100, and a backlight illumination device 140 is disposed below the bonded substrate 100. The video imaged by the camera 120 is displayed on the display device 150, and the control device 160 sets the outer peripheral chamfering of the bonded substrate 100 based on the imaging result. Note that the control device 160 also controls imaging of the camera 120, turning on / off the illumination of the side illumination device 130 and the backlight illumination device 140, rotation of the measurement table 112, and the like.

  In the step (f), the bonded substrate 100 is transferred from the measuring device 110 to the outer peripheral chamfering device 220. From the result obtained by measuring the bonded substrate 100 and obtained by the control device 160, the center position of the bonded substrate 100 obtained is aligned with the central axis of the rotary table 222. Using the grindstone 210 disposed on the outer peripheral portion of the bonded substrate 100, grinding is performed to a predetermined outer diameter position of the bonded substrate 100 obtained by the control device 160. The predetermined outer diameter position is often the outer diameter position of the glass substrate 20.

  Next, since the center is obtained, the bonded substrate 100 is processed to have a predetermined outer diameter and the outer periphery is chamfered, the process proceeds to step (g). The bonded substrate 100 is transported to the thinning position 240 and placed on the rotary table 242, and the back surface of the silicon wafer substrate 10 constituting the bonded substrate 100 is formed with a grindstone having the same size as the bonded substrate 100. The back grinding is uniformly performed until the thickness of the silicon wafer substrate 10 reaches a predetermined thickness, for example, 50 μm. Thereafter, although not shown, a tape is bonded to the back side of the thinned silicon wafer substrate 10, and the thinned silicon wafer substrate 10 with the tape is separated from the glass substrate 20 at the bonding means 30. .

  FIG. 2 shows an example of an apparatus that executes the steps (e) and (f) in the processing of the bonded substrate 100 shown in FIG. FIG. 2 is a plan view showing the measurement apparatus 110 according to the present invention incorporated in an existing wafer chamfering apparatus 310. The wafer chamfering apparatus 310 includes a supply / recovery unit 312, a measurement unit 314, a chamfering processing unit 316, a cleaning unit 320, a post-measurement unit 322, and a transfer unit 304. The control unit and the display unit are not shown.

  The supply / recovery unit 312 transports the bonded substrate 100 in the wafer cassette 330, which is carried from outside the apparatus 310 and placed in the cassette table 332, to the measuring unit 314, and after the processing is completed, the bonding is completed. The substrate 100 is stored in the wafer cassette 330. The supply / recovery unit 312 includes a supply / recovery robot 334 having a transfer arm 336 for handling the bonded substrate 100. The transfer arm 336 is provided on a slide block 340 that can move along the guide rail 338.

  The measurement unit 314 performs the step (e) of FIG. 1 on the bonded substrate 100 that is transferred from the wafer cassette 330 by the transfer arm 336. After the measurement unit 314 obtains the center position and the processing outer diameter of the bonded substrate 100, the transfer arm 364 transports the bonded substrate 100 from the measuring unit 314 to the chamfered processing unit 316. The transfer arm 364 is movable along the guide rail 300 of the transport unit 304. The processing unit 316 is provided with a plurality of grindstones 212 and 214, which are selectively used depending on the roughing processing or the processing target.

  In order to clean the bonded substrate 100 that has been chamfered by the processing unit 316 and inspect the processing state, the bonded substrate 100 is transferred from the processing unit 316 to the cleaning unit 320 using the transfer arm 365 of the cleaning transfer unit 302. And washed. Thereafter, the sample is transported to the rear measurement unit 322 by the transfer arm 366 of the storage transfer unit 306. The rear measurement unit 322 is provided with a measurement table 386, and the bonded substrate 100 is placed thereon, and the outer diameter is measured by the diameter measuring device 384. The bonded substrate 100 for which the measurement has been completed is accommodated in the wafer cassette 330 by the supply / recovery robot 334, and then transferred to the outside of the chamfering device 310 for thinning.

  Next, details of the method for measuring the bonded substrate 100 according to the present invention will be described with reference to FIGS. 3A and 3B are diagrams of the measurement device 110. FIG. 3A is a schematic perspective view showing the arrangement of the measurement device, and FIG. 3B is a measurement device 110 showing backlight imaging using the backlight illumination device 140. FIG. 3C is a schematic front view showing side illumination imaging using the side illumination device 130.

  On the table portion 116 of the measurement table 112 configured to be rotatable by a driving source 114 such as a motor, the bonded substrate 100 is sucked and fixed using a suction device (not shown) with the glass substrate 20 having a small diameter on the upper side. ing. The measurement table 112 is provided with means for detecting the circumferential position of the mounted bonded substrate 100, and outputs a change in the position of the bonded substrate 100 according to the circumferential movement angle of the measurement table 112. . The outer diameter of the table part 116 is configured to be smaller than that of the bonded substrate 100 to be placed. The measurement table 112 is controlled so that the rotation center position of the bonded substrate 100 does not change due to rotation.

  A backlight illuminating device 140 is arranged to be able to illuminate the backlight 142 so as to illuminate the peripheral portion below the bonded substrate 100. A side illumination device 130 capable of irradiating the side illumination 132 is disposed on a side portion of the bonded substrate 100 and at a position higher than the upper surface of the bonded substrate 100. The CCD camera 120 is disposed above the bonded substrate 100 so that the backlight 142 and the side illumination 132 can be received. The CCD camera 120 can image the peripheral edge of the bonded substrate 100.

  The image captured by the CCD camera 120 is obtained as a monochrome binary image. Between the center line of the measurement table 112 and the most prominent point (edge) of the measurement table 112 by obtaining the coordinates of the most prominent point (edge) of the convex portion in each image obtained by processing the captured image by a control device (not shown) The distance r is obtained for each point in the circumferential direction of the bonded substrate 100 by driving the drive source 114 to rotate.

  Here, in imaging by the CCD camera 120, only one of the side illumination device 130 and the backlight illumination device 140 is irradiated, and the other devices 140 and 130 stop irradiation (also referred to as exclusive operation). This is because the other illuminations 142 and 132 interfere with each other to make the captured image unclear or impossible to capture.

  Hereinafter, imaging using the backlight illumination device 140 will be described. In the bonded substrate 100, the transparent glass substrate 20 and the opaque silicon wafer substrate 10 overlap. Therefore, when light is irradiated from the overlapping direction, that is, when the bonded substrate 110 is placed on the table unit 116 of the measuring apparatus 110, the portion of the glass substrate 20 naturally emits light when the light is irradiated from above and below. In the portion where the silicon wafer substrate 10 is transmitted and overlapped with the glass substrate 20, light is blocked by the silicon wafer substrate 10 and light cannot pass through. As a result, if the light source is arranged in the vertical direction and the camera 120 is arranged to capture the illumination emitted from the light source in the vertical direction, the illumination from the part corresponding to the position of the silicon wafer substrate 10 does not reach the camera 120 and becomes black. Imaged. On the other hand, the part where only the glass substrate 20 is placed and the part corresponding to the space where nothing is placed are illuminated by the camera 120 and imaged in white. In the latter case, the luminance of the end surface of the glass substrate 20 may be reduced due to irregular reflection or the like, and in this case, the image is captured black by the camera 120 as an edge line.

  By the way, when the silicon wafer substrate 10 completely covers the glass substrate 20 when the bonded substrate 100 is placed on the measurement table 116, the relative position of the glass substrate 20 and the silicon wafer substrate 10 is set in the vertical direction. The determination cannot be made only with the arranged camera 120 and the illumination 142. This will be described with reference to FIG.

  FIG. 4 is a diagram illustrating an example of a state of the table unit 116 of the measurement apparatus 110 and an imaging result obtained by the camera 120. FIG. 4A shows a case where the silicon wafer substrate 10 completely covers the glass substrate 20, that is, only the silicon wafer substrate 10 needs to be chamfered. FIG. In this case, the glass wafer 20 is pasted and bonded, and in this case, a part of the glass substrate 20 needs to be chamfered. 4 (a) and 4 (b), the top is a plan view of the table 116 viewed from above, the second is a front view of the bonded substrate 100, and the third is FIG. 3 (b). The bottom row is an example of an image captured by the camera 120 using the side illumination device 130 described below. Reference numeral 122 in the plan view indicates a range imaged by the camera 120, that is, a measurement unit. 4A, when the silicon wafer substrate 10 covers the glass substrate 20, in the image 151a captured by the camera 120, the silicon wafer substrate is bordered by an arcuate edge. The portion 154a and the other portion 154b are compared in black and white. On the other hand, in the captured image 151b in which the glass substrate 20 partially protrudes from the silicon wafer substrate 10, the silicon wafer substrate portion 155a and the outside of the substrate 155b are shown in black and white contrast, and the contour of the silicon wafer formed in a convex arc shape ( Further, one convex arc (edge) 155e is formed outside the edge 155d. The edge 155 e is a locus of the end face of the glass substrate 20, and a portion between the edge 155 e and the edge 155 d corresponds to the glass substrate 20 protruding from the silicon wafer substrate 10.

  As shown in FIG. 4A, the position of the glass substrate 20 hidden behind the silicon wafer substrate 10 is not known only by photographing from above the bonded substrate 100 using illumination from above and below. Adopt edge detection using illumination from the side. The method described in Japanese Patent Laid-Open No. 2016-130738 (Patent Document 3) according to the prior application of the present applicant is applied.

  That is, the side illumination device 130 including LEDs that can be diffusely irradiated is disposed on a side surface of the bonded substrate 100 and at a position that is separated from the upper surface of the bonded substrate 100 by a predetermined distance H. Here, the LED capable of diffusing irradiation is, for example, an LED to which a diffusing unit (such as a diffusing plate) for diffusing light is attached. It is. Side illumination 132 from the side illumination device 130 is applied to the oblique chamfered portions formed on the peripheral portions of the silicon wafer substrate 10 and the glass substrate 20, respectively, and the reflected light enters the camera 120. This is shown in FIG.

The edge part of the glass substrate 20 arrange | positioned at the upper side is formed from the circumferential end surface 20a perpendicular | vertical to the upper surface 20c of a glass substrate, and the up-and-down chamfering surface 20b chamfered at an angle to this end surface 20a. Similarly, the silicon wafer substrate 10 disposed on the lower side is also formed of a circumferential end surface 10a and upper and lower chamfered surfaces 10b that are angled with respect to the end surface 10a. The end surfaces 10a and 20a and the chamfered surfaces 10b and 20b are formed by grinding with a grindstone using a dedicated chamfering machine. Therefore, it is formed on a surface having irregularities about the roughness of the grindstone. When such a surface is irradiated only with light from a direction parallel to the surface of the bonded substrate 100, for example, a part thereof is irregularly reflected and scattered. In this case, in the CCD camera 120, the glare in the image generated due to light from one direction is reduced. In order to further suppress the glare of the image, the side lighting device 130 includes a diffusing unit (diffusing plate) that diffuses light emitted from the LED light source. When incident light i _s1 and i _s2 irradiated from the light source is diffused by the diffusion plate and is incident on the chamfered surfaces 10b and 20b, reflected light r _s1 and r _s2 further scattered by the chamfered surfaces 10b and 20b is obtained, and the chamfers are obtained. The shape of the edge portions of the surfaces 10b and 20b can be measured with higher accuracy. The reflected light from the lower chamfered surfaces 10b and 20b and the reflected light from the upper surfaces 10c and 20c of the substrates 10 and 20 contribute to a decrease in measurement accuracy. Therefore, in this embodiment, the side lighting device 130 is arranged above the bonded substrate 100 so that the side lighting 132 from the side lighting device 130 does not enter the lower chamfered surfaces 10b and 20b as much as possible.

  An example measured by the CCD camera 120 using only the side illumination device 130 having the LED illumination provided with the reflection plate described above is the lowermost diagram in FIG. In the case of the captured image 153a in FIG. 4A, two arc-shaped white portions are obtained. The two arc-shaped white portions are the large diameter side on the convex portion side, that is, the left side in FIG. 4A is a silicon wafer substrate outline (edge) 156c in which the chamfered surface 10b of the silicon wafer substrate 10 is detected. That is, the right side in FIG. 4A is a glass substrate outline (edge) 156d in which the chamfered surface 20b of the glass substrate 20 is detected. The outer portion 156a of the silicon wafer substrate 10, the portion 156b of the silicon wafer substrate 10 only, and the bonding portion 156e of the silicon wafer substrate 10 and the glass substrate 20 are each imaged black. Thereby, the edge of the glass substrate 20 that could not be recognized by the backlight 142 in the vertical direction can be detected.

  On the other hand, in the case of FIG. 4B in which the glass substrate 20 protrudes from the silicon wafer substrate 10 and is bonded, two arc-shaped white portions are similarly detected. In FIG. 4B, the left side is a glass substrate outline (edge) 157c, and the right side is a silicon wafer substrate outline (edge) 157d. Then, the outer portion 157a of the bonded substrate 100, the portion 157b of the glass substrate 20 only, and the bonded portion 157e of the two substrates 10 and 20 are imaged black. When the side illumination 132 is used in this way, the edge portion of each of the substrates 10 and 20 of the bonded substrate 100 can be detected as two arcs in principle, but only this is the edge of the silicon wafer substrate 10 or the edge of the glass substrate 20. I do n’t know. By using the image using the backlight 142 together, it is possible to determine the distinction between the two edges detected by the side illumination 132.

  Next, an example of a method for determining the bonded substrate effective radius R that is the radius of the maximum substrate that can be taken out from the bonded substrate 100 using the captured image and the center O in that case will be described with reference to FIG. FIG. 6 shows a method for obtaining the effective radius of the bonded substrate 100 from the points obtained by placing the bonded substrate 100 on the measurement table 112 and rotating the measurement table 112 by a predetermined angle in the circumferential direction. 6A and 6B show a case where a part of the glass substrate 20 protrudes from the silicon wafer substrate 10 and corresponds to FIG. 4B. In the case of FIG. 4A, since the silicon wafer substrate 10 completely covers the glass substrate 20, if a chamfering process is performed along the outline (edge) of the glass substrate 20, a bonded substrate having a perfect circle and a predetermined diameter is obtained. Is obtained.

On the other hand, in the case shown in FIG. 4B, when the outer diameter of the bonded substrate is obtained using only the backlight 142, the measurement points 172 ₁ ... 172 _i . _The extraction contour 171 obtained from _n becomes an ellipse or gourd shape that is long in the direction in which the glass substrate 10 protrudes. As a result, the effective perfect circle 170 that can be taken out from the bonded substrate 100 becomes the bonded substrate 100 that does not include the silicon wafer substrate 10 but includes only the glass substrate 20, and accordingly, the center position O ′ is also shifted from the true position. . On the other hand, according to the method of the present invention, as shown in FIG. 6B, the measurement points 174 ₁ ... 174 _i ... 174 _n are located on the extraction contour 173 that always includes both the silicon wafer substrate 10 and the glass substrate 20. The effective perfect circle 175 and the center position O obtained based on the extracted contour 173 indicate the size and center of the maximum true circle that can be taken out from the bonded substrate 100.

  Next, FIG. 7 shows a flowchart of a processing method including the method for measuring the bonded substrate 100 described above. First, in step S700, the bonded substrate 100 on which the glass substrate 20 and the silicon wafer substrate 10 are bonded is suction-fixed and arranged at the measurement position (measurement table 112) of the measurement device 110. Here, the bonded substrate 100 can be rotated together with the measurement table 112 with its rotation center position fixed. Next, in step S710, the backlight 142 is irradiated from the backlight illumination device 140. At this time, the side illumination device 130 is turned off. In this state, the edge portion of the bonded substrate 100 is imaged using the camera 120 (step S720). Next, the backlight illumination device 140 is turned off and the side illumination device 130 irradiates the side illumination 132 (step S730). In this state, the camera 120 is used to image the edge portion of the bonded substrate 100. The captured image is compared with the image captured by the backlight illumination device 140, and the edge of the portion where the silicon wafer substrate 10 and the glass substrate 20 are laminated is specified. A distance R from the rotation center of the measurement table 112 to the specified edge portion is obtained (step S740). The measurement table 112 is rotated by a predetermined angle or an arbitrary angle, and the above steps S710 to S740 are repeated a plurality of times at least four times for the entire circumference (step S750). Thereby, the curve of the outline (edge) of the laminated portion of the silicon wafer substrate 10 and the glass substrate 20 of the bonded substrate 100 is determined (step S760). Based on the determined curve, a center position and a radius on the bonded substrate 100 that is the maximum effective perfect circle are calculated (step S770). Since the processing amount of the bonded substrate 100 has been determined, the bonded substrate is transferred to the chamfering machine (step S780). Based on the center position and the radius obtained in step S770, chamfering is performed with a chamfering machine to produce a perfect bonded substrate 100 having a predetermined outer diameter (step S790). The bonded substrate 100 is subsequently conveyed to a thinning apparatus or the like.

  In the above embodiment, the measurement is performed with an existing chamfering machine, but a measuring device may be provided separately from the chamfering machine. In short, it is only necessary that the chamfering can be accurately performed with less contamination based on the measurement result. In the present invention, the bonded substrate includes a silicon wafer substrate as an example. However, the substrate on which the semiconductor element is formed is not limited to the silicon wafer substrate. However, it is necessary to be a non-transparent substrate. Further, the present invention is more effective when the thickness of the substrate to be processed such as thinning is thin, but the present invention is also effective in the case of a wafer substrate that is thin to about 100 μm without being thinned.

DESCRIPTION OF SYMBOLS 10 ... Silicon wafer substrate, 10a ... End surface, 10b ... Chamfered surface, 10c ... Silicon wafer substrate upper surface, 15 ... Inversion, 20 ... Glass substrate, 20a ... End surface, 20b ... Chamfered surface, 20c ... Glass substrate upper surface, 30 ... Adhesive means , 100 ... Bonded substrate, 110 ... Measuring device, 112 ... Measuring table, 114 ... Drive source, 116 ... Table unit, 118 ... Center axis, 120 ... (CCD) camera, 122 ... Measuring unit, 130 ... Side illumination device, 132 ... side illumination, 140 ... backlight illumination device, 142 ... backlight, 150 ... display device, 151a, 151b ... captured image (backlight), 153a, 153b ... captured image (side illumination), 154a ... silicon wafer substrate part 154b ... outside substrate, 155a ... silicon wafer substrate portion, 155b ... outside substrate, 155c ... ga Substrate portion, 155d ... silicon wafer substrate contour, 155e ... edge, 156a ... bonded substrate portion, 156b ... inter-substrate portion, 156c ... silicon wafer substrate contour, 156d ... glass substrate contour, 157a ... bonded substrate portion, 157b ... Inter-substrate portion, 157c ... glass substrate contour, 157d ... silicon wafer substrate contour, 160 ... control device, 170 ... effective perfect circle, 171 ... extraction contour, 172 ₁ ... 172 _i ... 172 _n ... measurement point, 173 ... extraction contour, 174 ₁ ... 174 _i ... 174 _n ... Measurement point, 175 ... Effective perfect circle, 210, 212, 214 ... Grinding stone, 220 ... Perimeter chamfering device, 222 ... Rotary table, 230 ... Grinding wheel, 240 ... Thinning position, 242 ... Rotating table 300 ... guide rail 302 ... cleaning transfer unit 304 ... conveying unit 306 ... storage tray 310 ... Wafer chamfering device, 312 ... Supply / recovery unit, 314 ... Measurement unit, 316 ... Processing unit, 320 ... Cleaning unit, 322 ... Post measurement unit, 330 ... Wafer cassette, 332 ... Cassette table, 334 ... Supply / recovery Robot, 336 ... Transfer arm, 338 ... Guide rail, 340 ... Slide block, 364, 365, 366 ... Transfer arm, 384 ... Diameter, 386 ... Measurement table, H ... Height deviation, i _s1 , _is2 ... incident light, O, O '... center, R ... bonded substrate effective radius, r ... radius, r _s1 , r _s2 ... reflected light

Claims (7)

In a method for measuring a bonded substrate formed by bonding a transparent second substrate to a first substrate on which a semiconductor element is formed via an adhesive means,
Placing the bonded substrate on a rotary table;
A camera capable of measuring a contour portion of the bonded substrate above the bonded substrate, a side illumination unit at a position higher than a top surface of the bonded substrate on a side of the bonded substrate, and the bonded substrate The backlight means is provided below each,
The side illumination means and the backlight means are operated exclusively with each other to capture two types of images of the outline of the bonded substrate board,
Obtain the edge of the overlapping portion of the first substrate and the second substrate from the two types of captured images,
A method for measuring a bonded substrate, characterized in that an inscribed circle and a center thereof are obtained from the obtained edge. The first substrate is a silicon wafer substrate;
The second substrate is a glass substrate;
The outer diameter of the first substrate before measurement is larger than the outer diameter of the second substrate;
The method for measuring a bonded substrate according to claim 1, wherein the side illumination unit includes a diffusion unit that diffuses light. The edge of the overlapping portion is
When a dark part line is further recognized outside the dark part in the captured image in the backlight illumination, it is regarded as an end part of the dark part in the captured image.
When only the bright part is recognized outside the dark part in the captured image in the backlight illumination, it is regarded as the inner line of the two curves in the corresponding captured image in the side illumination.
The method for measuring a bonded substrate according to claim 1 or 2, wherein: After the method for measuring a bonded substrate according to any one of claims 1 to 3,
Based on the center of the inscribed circle determined from the edge of the overlapping portion, the bonded substrate is rotated around the center,
A method for processing a bonded substrate, wherein a grindstone is brought into contact with the outer peripheral portion and ground from the center of the inscribed circle to a radial position thereof. In a bonded substrate measuring apparatus formed by bonding a transparent second substrate to a first substrate on which a semiconductor element is formed via an adhesive means,
A camera disposed above the bonded substrate for imaging the bonded substrate mounted on a rotary table;
Side illumination means disposed on a side of the bonded substrate and higher than the upper surface of the bonded substrate;
Backlight means disposed below the bonded substrate;
Control means for operating the side illumination means and the backlight means exclusively of each other,
By operating the side illumination unit and the backlight unit exclusively with each other by the control unit, the camera can capture two different types of images about the outline of the bonded substrate board,
The control means obtains the edge of the overlapping portion of the first substrate and the second substrate from the two types of captured images, and obtains an inscribed circle and its center from the obtained edge. apparatus.   The first substrate is a silicon wafer substrate, the second substrate is a glass substrate, the outer diameter of the first substrate before measurement is larger than the outer diameter of the second substrate, and the side illumination means The apparatus for measuring a bonded substrate according to claim 5, further comprising a diffusing unit that diffuses light. Each of the first and second substrates constituting the bonded substrate has a chamfered periphery.
The said camera detects reflected light from the part of the chamfered shape when the side illumination means is operating, and picks up an image by distinguishing the outline shape of the bonded substrate board from other parts. Item 7. The bonded substrate measurement apparatus according to Item 5 or 6.