JP2008036737A - Manufacturing method for optical substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for an optical substrate, which improves the strength of the optical substrate and productivity in manufacturing the optical substrate. <P>SOLUTION: In the manufacturing method of a crystal substrate 11, a plurality of crystal substrates 11 is closely fixed so that the main surface of the crystal substrate 11 and the main surface of the other crystal substrate 11 are fitted. The side surfaces of the plurality of closely fixed crystal substrates 11 are processed by lap polishing with a grinding wheel to remove micro cracks. The plurality of crystal substrates 11 are then closely fixed by changing the direction, the corner and the edge line part of the crystal substrate 11 are processed by chamfering to form the corner chamfering part and the edge line chamfering part 13. The chamfering is performed by lap polishing to remove the micro cracks. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical substrate, and more particularly, to a method for manufacturing an optical substrate in which chamfering or polishing is performed on the optical substrate.

  The above-described optical substrate is, for example, a quartz substrate, and is used as a cover for protecting the solid-state imaging device. The quartz substrate is cut from the raw quartz and ground to obtain further dimensions. During this cutting process or grinding process, the processed surface of the quartz substrate becomes relatively rough, and microcracks or the like may occur. Dust may be generated or chipped due to micro cracks. When a quartz substrate is used as a cover, this dust or chipped part comes into contact with the solid-state image sensor, adversely affecting the solid-state image sensor. There was a problem of affecting.

  Further, when the solid-state imaging device is sealed with the package and the quartz substrate, there is a problem that the quartz substrate is damaged without being able to withstand the sealing force due to the generation of microcracks. In addition, since the ridge portion of the quartz substrate has a corner, the strength of the quartz substrate is relatively weak, and there is a problem that the quartz substrate is damaged when sealing. The main surface of the quartz substrate is finished by polishing or the like.

  Therefore, after manually chamfering the ridgeline portion on the side surface (end surface) of the quartz substrate, for example, as described in Patent Document 1, the side surface including the chamfered portion is polished into an arc shape (curved surface shape). By doing so, the microcracks are removed.

JP 2004-148460 A

  However, since the chamfering process and the polishing process are performed manually, there is a problem in that the chamfering amount and the polishing amount vary greatly. For example, if the polishing amount is small, the microcracks may not be completely removed, and if the chamfering amount is large, the side surface (end surface) of the quartz substrate may have an acute angle and may be easily chipped. As described above, there is a problem that the strength of the quartz substrate is lowered. In addition, there is a problem that productivity is poor due to manual chamfering and polishing.

  It is an object of the present invention to provide a method for manufacturing an optical substrate that can improve the strength of the optical substrate and improve the productivity when manufacturing the optical substrate.

  In order to solve the above-described problem, a method for manufacturing an optical substrate according to the present invention includes a plurality of optical substrates in which a main surface that transmits light and a main surface of another optical substrate in a rectangular flat optical substrate are brought into close contact with each other. The method includes a step of closely fixing the substrate, and a step of performing a polishing process capable of removing microcracks on the side surfaces of the plurality of optical substrates that are firmly fixed.

  According to this method, since the polishing process is performed on the side surfaces of the plurality of optical substrates that are closely fixed, even if the micro cracks are present on the side surfaces of the optical substrate, the micro cracks can be removed. Therefore, it is possible to suppress the occurrence of chipping or the like on the side surface of the optical substrate due to the microcracks. Furthermore, even if an external force (for example, sealing force) is applied to the optical substrate, since the generation of microcracks is suppressed, it is possible to suppress a decrease in the strength of the optical substrate. In addition, since a plurality of optical substrates are overlapped and the side surfaces of the optical substrate are simultaneously polished, productivity of performing polishing can be improved as compared with performing polishing by hand.

  In the method for manufacturing an optical substrate according to the present invention, the optical substrate is tilted to an angle at which a chamfering process can be performed on the ridge line portion of the optical substrate, and the main surface of the optical substrate and the other optical substrate A step of fixing the plurality of optical substrates in close contact with each other and a chamfering process capable of removing microcracks on the ridge portions of the plurality of optical substrates fixed in close contact And a step of forming a ridge line chamfered portion.

  According to this method, since the ridge line portions of a plurality of optical substrates are simultaneously chamfered by the step of forming the ridge line chamfered portion, the variation in the chamfer amount is reduced as compared with the case where the chamfering is manually performed. In addition, the productivity of chamfering can be improved. In addition, since a ridge line chamfered portion capable of removing microcracks is formed in the ridge line portion of the optical substrate, a special treatment is performed in comparison with performing a curved surface polishing process on the side surface (end surface) of the optical substrate. Chamfering (polishing) can be performed relatively easily without using a tool (special jig) to control processing.

  In the method for manufacturing an optical substrate according to the present invention, the optical substrate is tilted to an angle at which the plurality of optical substrates can be chamfered to corners of the optical substrate, and the main surface of the optical substrate and the other optical substrate are A step of chamfering the plurality of optical substrates in close contact with a main surface and chamfering the corners of the plurality of optical substrates fixed in contact with each other to remove microcracks. Forming a portion.

  According to this method, the corner chamfered portion that can remove microcracks is formed in the corner of the optical substrate by the step of forming the corner chamfered portion, so that the corner of the optical substrate is not chamfered. Thus, the strength of the optical substrate can be improved. In addition, since a plurality of optical substrates are stacked and the corners of the plurality of optical substrates are chamfered at the same time, the productivity of performing chamfering can be improved as compared with chamfering by hand. .

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings.

  FIG. 1 is a perspective view schematically showing a structure of a quartz crystal substrate as an optical substrate. Hereinafter, the structure of the quartz substrate will be described with reference to FIG.

  As shown in FIG. 1, the quartz substrate (wafer) 11 is used as a cover for sealing a solid-state imaging device (none of which is shown) housed in a package, for example. The quartz substrate 11 has a rectangular flat plate shape (substantially cubic), and the planar size of the main surface 11a is, for example, 32 mm × 22 mm. Moreover, the thickness H of the quartz substrate 11 is, for example, 0.7 mm.

  The quartz substrate 11 has a main surface 11a and a side surface 11b. The main surface 11a is a surface through which light is transmitted. At the four corners of the quartz substrate 11, corner chamfered portions 12 that are part of the side surface 11 b for improving the strength of the quartz substrate 11 are formed. The corner chamfered portion 12 is, for example, a C surface (45 ° slope). As for the chamfering dimensions of the corner chamfered portion 12, for example, one place is C1.5 mm and the remaining three places are C0.5 mm. In this way, since the crystal substrate 11 can be oriented by making the chamfer amount at one location larger than the chamfer amounts at the other three locations, the optical direction of the crystal substrate 11 can be changed in a post-process or the like. Recognition and determination are possible.

  The ridge line portion of the quartz substrate 11 is chamfered to improve the strength of the quartz substrate 11. Note that the chamfered portion is referred to as a ridge line chamfered portion 13. The ridge line chamfered portion 13 is, for example, a C surface (45 ° slope) in the same manner as the corner chamfered portion 12. The chamfer dimension of the ridge line chamfer 13 is, for example, C 0.2 mm.

  Further, the side surface 11b, the corner chamfered portion 12, and the ridge line chamfered portion 13 of the quartz substrate 11 are subjected to lapping as a polishing process for removing microcracks generated when the quartz substrate 11 is cut and ground. Has been. The main surface 11a of the quartz substrate 11 is finished to a mirror surface by polishing.

  2 to 10 are schematic views showing a method of manufacturing a quartz substrate in the order of steps. (A) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side. Hereinafter, a method for manufacturing a quartz substrate will be described with reference to FIGS.

  In the step shown in FIG. 2, a lambard process is performed in order to convert the quartz crystal, which is the basis of the quartz substrate 11, into the quartz block 14. Lumbard processing is surface grinding for clarifying the X-axis, Y-axis, and Z-axis of the quartz crystal. For example, a rotary surface grinding machine is used as a method for performing the lambard process. The particle size of the grindstone of the rotary surface grinder is, for example, # 80. By the processing as described above, the X surface 14a, Y surface 14b, and Z surface 14c corresponding to the X axis, Y axis, and Z axis of the quartz block 14 are determined. It should be noted that microcracking may occur on the ground surface after the lumbar processing.

  In the step shown in FIG. 3, the crystal block 14 is cut along a desired angle in order to obtain the crystal substrate 11 having desired characteristics. For cutting the crystal block 14, for example, a wire saw cutting method is used. First, for example, the crystal block 14 is fixed to an iron plate via a dummy glass (both not shown). The crystal block is attached to the dummy glass using, for example, a shift wax adhesive. Next, in order to obtain the crystal substrate 11 having desired characteristics from the crystal block 14, for example, the crystal block 14 is cut at an angle of 45 °. The cut wide area surface becomes a main surface 11 a of the quartz substrate 11.

  In the process shown in FIG. 4, preparation is performed for processing the dimension in the height direction (dimension B in FIG. 5) and the dimension in the width direction (dimension A in FIG. 5) of the quartz substrate 11 into desired dimensions. First, the quartz substrate 11 cut at an angle of 45 ° in the previous step is separated from the dummy glass. As a method of separation, the quartz substrate 11 is peeled off from the dummy glass by using a hot plate or the like, for example, by heating the adhesive to 80 ° C. Next, as shown in FIG. 4, the main surfaces 11a of the separated crystal substrates 11 are fixed together. As a method for fixing the plurality of quartz substrates 11, for example, a shift wax adhesive as described above is used. The optical axis (Y axis, Z axis) of the quartz substrate 11 is in the direction as shown in FIG.

  In the process shown in FIG. 5, the quartz substrate 11 is ground so that the dimension (B dimension) in the height direction and the dimension (A dimension) in the width direction of the quartz substrate 11 become desired dimensions. As a grinding method, for example, a rotary surface grinder is used. The particle size of the grindstone of the rotary surface grinder is, for example, # 270.

  Specifically, in the formation of the crystal block 14 in FIG. 2, for example, when the dimension in the width direction (A dimension) has already been completed to a desired dimension, only the side surface 11b in the height direction (B dimension) is ground. And finish to dimension B. In addition, in the formation of the crystal block 14 in FIG. 2, when the dimension in the width direction (A dimension) is not completed, the side surface 11b of the crystal substrate 11 is ground and both the A dimension and the B dimension are set to desired dimensions. Finish. In addition, the microcrack may have generate | occur | produced on the ground grinding surface (side surface 11b).

  In the step shown in FIG. 6, lapping is performed on the side surface 11 b of the quartz substrate 11. As a method for performing lapping, for example, a lapping apparatus is used. The particle size of the grindstone of the lapping machine is # 3000. Specifically, the microcracks generated on the side surface 11b of the quartz substrate 11 can be removed by cutting or grinding, and no new microcracks are generated when lapping is performed. It is a condition to select. In addition, it is desirable that the processing speed of lapping to remove microcracks is fast.

  First, one side of the side surface 11b according to the dimension B of the quartz substrate 11 is lapped. Next, lapping is applied to the remaining other side surface to finish the dimension B. Thereafter, similarly to the above-described method, lapping is performed on one side surface and the other side surface related to the A dimension to finish the A dimension. The surface roughness of the lapping surface (side surface 11b) lapped using a # 3000 grindstone is, for example, Ra (center line average roughness) of 0.1 μm to 0.2 μm. As described above, the four surfaces 11b of the quartz substrate 11 are finished to be polished surfaces polished with a # 3000 grain grindstone.

  In the process shown in FIG. 7, corner chamfering is performed on corners (four corners) of the quartz substrate 11 in order to increase the strength of the quartz substrate 11. As an apparatus for performing the corner chamfering process, for example, a lapping apparatus is used. The particle size of the grindstone used in this lapping apparatus is # 3000. 7 shows the state after the corner chamfered portion 12 is formed.

  More specifically, the corner chamfering process is performed by simultaneously processing a plurality of crystal substrates 11 in a state where the plurality of quartz crystal substrates 11 are closely fixed. The corner chamfered portion 12 formed by the corner chamfering process is, for example, a 45 ° C-plane. As described above, the corner chamfered portion 12 has a dimension of, for example, one of four corners of C1.5 mm and the remaining three of C0.5 mm. Further, the surface roughness of the corner chamfered portion 12 is, for example, Ra (center line average roughness) of 0.1 μm to 0.2 μm.

  In the step shown in FIG. 8, preparation is made for forming a ridge line chamfered portion 13 (see FIGS. 1, 9, and 10) on the ridge line portion 15 of the quartz substrate 11. First, the plurality of crystal substrates 11 that are closely fixed when the corner chamfered portion 12 is formed are peeled off by heating the adhesive to, for example, 80 ° C. using a hot plate or the like. Next, the plurality of crystal substrates 11 are closely fixed so that the ridge line portions 15 to be chamfered in the crystal substrates 11 can come into contact with the grindstone of the lapping apparatus.

  Specifically, an inclined block 22 having an inclined wall 21 is used. The inclined wall 21 is inclined at 45 ° with respect to the bottom surface 22a, for example. Following the angle of the inclined wall 21, the main surfaces 11a of the plurality of crystal substrates 11 are aligned and fixed in close contact. As a method of closely fixing, a shift wax-based adhesive as described above is used. The number of quartz substrates 11 that can be chamfered at one time is, for example, 70.

  Further, by arranging a plurality of quartz substrates 11 and measuring the height with a point P in a wide range as a reference point as shown in FIG. 8, the parallelism (width direction, depth direction, height) of X and Y is measured. (Direction) can be improved, and variation in the chamfering amount of the ridge line chamfered portion 13 can be suppressed. Thus, the ridge line chamfered portion 13 can be formed on the ridge line portion 15.

  In the step shown in FIG. 9, chamfering is performed on one ridge line portion 15 among the plurality of ridge line portions 15 in the crystal substrate 11. In the quartz substrate 11 shown in FIGS. 9 and 10, the corner chamfered portion 12 is not shown. As an apparatus for chamfering the ridge line portion 15, for example, a lapping apparatus is used. The particle size of the grindstone used in this lapping apparatus is # 3000. Moreover, the lapping apparatus for forming the ridge line chamfered portion 13 is configured to be capable of simultaneously polishing the vertical direction of the workpiece (quartz substrate 11), for example.

  More specifically, the lapping apparatus is provided with a carrier (not shown) for supporting a quartz substrate block 23 to which a plurality of quartz substrates 11 are closely fixed. Further, in the lapping apparatus, an upper polishing grindstone 24a and a lower polishing grindstone 24b are arranged above and below the supported quartz substrate block 23. When these grindstones slide horizontally, for example, the quartz substrate block 23 can be lapped (chamfered) at the same time. The chamfering amount of the ridge line chamfered portion 13 is, for example, C 0.2 mm. The ridge line chamfered portion 13 is formed only by lapping because the chamfering amount is relatively small at C 0.2 mm.

  In the process shown in FIG. 10, chamfering of the other ridge line portion 15 is performed. First, as described above, the plurality of quartz substrates 11 that are closely fixed are peeled off using a hot plate or the like. Next, the quartz substrate 11 is inclined and fixed in a state where chamfering of the ridge line part 15 different from the ridge line part 15 which has been chamfered in the previous process is possible. In addition, when making it incline at a predetermined angle (for example, 45 degrees), the main surfaces 11a of the quartz substrate 11 are aligned and fixed together using the inclined block 22 (see FIG. 8) as described above. In addition, as a method of fixing the plurality of quartz substrates 11, the above-described adhesive is used. In addition, as shown in FIG. 8, parallel projection is performed using the point P of the plurality of crystal substrates 11 as a reference point.

  Thereafter, chamfering of all the ridge lines 15 in the quartz substrate 11 is performed. For example, the ridge line chamfered portion 13 is formed on all the ridge line portions 15 of the quartz substrate 11 eight times including the ridge line portion of the corner chamfered portion 12. As described above, the side surface 11b, the corner chamfered portion 12, and the ridge line chamfered portion 13 in the quartz substrate 11 are finished as polished surfaces that are lapped with a grain size of # 3000. Further, by simultaneously polishing a plurality of quartz substrates 11 using a lapping apparatus, variation in the chamfering amount of the corner chamfered portion 12 and the ridgeline chamfered portion 13 in one quartz substrate 11 and the plurality of quartz substrate 11 is achieved. Can be suppressed. The main surface 11a of the quartz substrate 11 is completed by being polished to a mirror finish.

  As described above in detail, according to the method for manufacturing the quartz substrate 11 of the present embodiment, the following effects can be obtained.

  (1) According to the method for manufacturing the quartz substrate 11 of the present embodiment, the grinding stone capable of removing microcracks by polishing the side surface 11b of the quartz substrate 11, chamfering the corner, and chamfering the ridge line portion 15. Since the lapping is performed using, the microcracks can be removed even if microcracks are generated on the side surface 11b of the quartz substrate 11 during the cutting or grinding of the quartz substrate 11. Therefore, it is possible to suppress the occurrence of chipping or the like on the side surface 11b of the quartz substrate 11 due to the microcracks. Furthermore, even if an external force (for example, sealing force) is applied to the quartz substrate 11, since the generation of microcracks is suppressed, it is possible to suppress the strength of the quartz substrate 11 from being lowered. In addition, since a plurality of quartz substrates 11 are simultaneously chamfered using a lapping apparatus, the variation in the chamfering amount is reduced as compared to performing chamfering (polishing) one by one by hand. In addition, the productivity for performing chamfering (polishing) can be improved.

  (2) According to the method of manufacturing the quartz substrate 11 of the present embodiment, lapping is performed using a # 3000 grain grindstone, so that the existing microcracks can be removed and lapping is performed. When this is done, generation of new microcracks can be suppressed. Therefore, it can suppress that the intensity | strength of the quartz substrate 11 falls, As a result, the quartz substrate 11 which can endure with respect to sealing force etc. can be manufactured.

  (3) According to the method for manufacturing the quartz substrate 11 of the present embodiment, the ridge line chamfered portion 13 is formed on the side surface (end surface) of the rectangular quartz substrate 11, so that the side surface of the quartz substrate is polished in an arc shape (curved surface shape). Compared with processing, lapping can be performed relatively easily without using a special jig (dedicated jig) to control the processing.

  (4) According to the method for manufacturing the quartz substrate 11 of the present embodiment, the chamfering amount of one corner chamfered portion 12 in the quartz substrate 11 is made larger than the chamfering amounts of the other three corner chamfered portions 12. As a result, the crystal substrate 11 can be oriented, so that the optical direction of the crystal substrate 11 can be recognized and determined in a subsequent process or the like.

  In addition, this embodiment is not limited above, It can also implement with the following forms.

  (Modification 1) As described above, the ridge line chamfered portion 13 is formed on the ridge line portion 15 using the lapping apparatus, and the ridge line portion 15 in the vertical direction of the quartz substrate 11 is formed by the upper polishing grindstone 24a and the lower polishing grindstone 24b. For example, after forming the ridge line chamfered portion 13 on one ridge line portion 15 of the quartz substrate 11 by using another lapping polishing apparatus, the quartz substrate 11 is turned upside down, and the other Alternatively, the ridge line chamfered portion 13 may be formed on the ridge line portion 15 to form the ridge line portions 15 separately.

  (Modification 2) As described above, instead of forming the corner chamfered portion 12 and the ridgeline chamfered portion 13 only by lapping, the corner chamfered portion and the ridgeline chamfered portion were formed by another grinding method (polishing method). Further, the corner chamfered portion 12 and the ridgeline chamfered portion 13 may be finished by lapping with a particle size of # 3000.

  (Modification 3) As described above, it is not limited to the lapping (# 3000) of the side surface 11b of the quartz substrate 11 one by one. For example, the lapping is performed simultaneously on the upper and lower surfaces of the side surface 11b. It may be.

  (Modification 4) As described above, the upper polishing grindstone 24a and the lower polishing grindstone 24b of the lap polishing apparatus are not limited to performing lap polishing, and for example, the upper polishing grindstone and the lower polishing grindstone rotate. Such a rotation type lapping apparatus may be used.

  (Modification 5) As described above, the particle size of the grindstone used in the lapping apparatus is not limited to # 3000. For example, in consideration of the processing time for lapping, the micro-crystal generated on the quartz substrate 11 is considered. A grindstone having a grain size that can remove cracks and does not generate new microcracks when lapped.

  (Modification 6) As described above, the corner chamfered portion 12 of the quartz substrate 11 may be finished with only the corner chamfered portion 12 without performing the ridgeline chamfered portion instead of performing the ridgeline chamfered portion.

The perspective view which shows typically the structure of the quartz substrate which concerns on embodiment of this invention. It is a schematic diagram which shows the manufacturing method of a quartz substrate in order of a process, (a) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side. It is a schematic diagram which shows the manufacturing method of a quartz substrate in order of a process, (a) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side. It is a schematic diagram which shows the manufacturing method of a quartz substrate in order of a process, (a) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side. It is a schematic diagram which shows the manufacturing method of a quartz substrate in order of a process, (a) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side. It is a schematic diagram which shows the manufacturing method of a quartz substrate in order of a process, (a) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side. It is a schematic diagram which shows the manufacturing method of a quartz substrate in order of a process, (a) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side. It is a schematic diagram which shows the manufacturing method of a quartz substrate in order of a process, (a) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side. It is a schematic diagram which shows the manufacturing method of a quartz substrate in order of a process, (a) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side. It is a schematic diagram which shows the manufacturing method of a quartz substrate in order of a process, (a) is a perspective view which shows typically the manufacturing method of a quartz substrate, (b) is a schematic side view which looked at the quartz substrate from the side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Quartz substrate as an optical substrate, 11a ... Main surface, 11b ... Side surface, 12 ... Corner chamfer part, 13 ... Ridge chamfer part, 14 ... Crystal block, 14a ... X surface, 14b ... Y surface, 14c ... Z surface, DESCRIPTION OF SYMBOLS 15 ... Ridge line part, 21 ... Inclined wall, 22 ... Inclined block, 22a ... Bottom surface, 23 ... Quartz substrate block, 24a ... Upper polishing grindstone, 24b ... Lower polishing grindstone

Claims (3)

A step of closely fixing a plurality of optical substrates by closely adhering a main surface that transmits light in a rectangular flat optical substrate and a main surface of another optical substrate;
Applying a polishing process capable of removing microcracks on the side surfaces of the plurality of optical substrates that are closely fixed; and
A method of manufacturing an optical substrate, comprising: It is a manufacturing method of the optical substrate according to claim 1,
The optical substrate is tilted at an angle that allows chamfering to be performed on the ridge line portion of the optical substrate, and the main surface of the optical substrate and the main surface of the other optical substrate are brought into close contact with each other. A step of closely fixing the optical substrate;
Forming a ridge line chamfered portion by chamfering the ridgeline portions of the plurality of optical substrates that are closely fixed to each other to remove microcracks; and
A method of manufacturing an optical substrate, comprising: It is a manufacturing method of the optical substrate according to claim 1 or 2,
The optical substrate is tilted at an angle that allows chamfering to the corners of the optical substrate, and the main surface of the optical substrate and the main surface of the other optical substrate are brought into close contact with each other. A step of closely fixing the substrate;
Forming a corner chamfered portion by performing chamfering capable of removing microcracks in the corners of the plurality of optical substrates fixedly fixed;
A method of manufacturing an optical substrate, comprising:

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