Glass sheet manufacturing method and glass cap manufacturing method

Abstract

To provide a glass sheet manufacturing method capable of improving productivity at the time of mass-producing dome-like glass caps.SOLUTION: A glass sheet manufacturing method includes: a temporary joint step of temporarily jointing a first face 2a of a glass sheet 2 and a second face 2b on an opposite side to a substrate 16, on which plural circular concave parts 18 are formed; a projection part formation step of forming plural projection parts 4 on the glass sheet 2 by heating the glass sheet 2 and the substrate 16 to temperature higher than a softening point of the glass sheet 2 and lowering pressure around the glass sheet 2 and the substrate 16 to project a portion of the glass sheet 2 corresponding to the plural circular concave parts 18 in a dome-like shape on the first face 2a of the glass sheet 2; and a removal step of removing the substrate 16 temporarily jointed to the glass sheet 2 by grinding or polishing the substrate 16 temporarily jointed to the glass sheet 2.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a glass sheet and a method for manufacturing the glass sheet that enable improvement in productivity when mass-producing dome-shaped (hollow hemispherical) glass caps. [Background technology]

[0002] In recent years, dome-shaped glass caps have been mounted on various devices (for example, laser diodes, photodiodes, light-emitting diodes, MEMS mirrors, etc.) In general, dome-shaped glass caps are attached to various devices using a sealing solder material (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-174852 Summary of the Invention [Problem to be solved by the invention]

[0004] However, dome-shaped glass caps are manufactured on a chip-by-chip basis using a molding process, making them unsuitable for mass production. Furthermore, the process of coating the glass cap with the sealing solder material must also be performed on a chip-by-chip basis. Furthermore, if the dimensions or shape of the glass cap are changed, a new mold must be created. Furthermore, when using a mold, differences in the expansion coefficients of the mold material and the glass material have an impact, limiting the size of glass caps that can be mass-produced (for example, glass caps with a diameter of 50 mm or more). For these reasons, there is a need to improve productivity when mass-producing dome-shaped glass caps.

[0005] An object of the present invention is to provide a glass sheet and a method for manufacturing the glass sheet that enable improvement in productivity when mass-producing dome-shaped glass caps. [Means for solving the problem]

[0006] According to the present invention, there is provided the following glass sheet that solves the above problems: "A flat glass sheet having a plurality of dome-shaped protrusions, the diameter of each of the protrusions being less than 50 mm when viewed in a direction perpendicular to the first surface of the glass sheet having the plurality of protrusions" is provided.

[0007] The plurality of protrusions protrude toward the first surface of the glass sheet, and the second surface of the glass sheet opposite the first surface preferably has at least one solder portion coated with a solder material around the plurality of protrusions in a portion where the plurality of protrusions are not formed. The number of the solder portions is preferably the same as the number of the plurality of protrusions, and the plurality of solder portions are preferably formed around each of the plurality of protrusions.

[0008] According to the present invention, there is also provided the following method for producing a glass sheet, which solves the above-mentioned problems: "A method for manufacturing a flat glass sheet having a plurality of dome-shaped protrusions on a first surface, a temporary bonding step of temporarily bonding a second surface of the glass sheet opposite to the first surface to a substrate having a plurality of circular recesses formed thereon; a protrusion forming process in which the glass sheet and the substrate are heated to a temperature higher than the softening point of the glass sheet, and a pressure around the glass sheet and the substrate is reduced, thereby causing portions of the glass sheet corresponding to the plurality of circular recesses to protrude in the dome shape toward the first surface of the glass sheet, thereby forming the plurality of protrusions on the glass sheet; and a removal step of removing the substrate temporarily bonded to the glass sheet by grinding or polishing the substrate temporarily bonded to the glass sheet."

[0009] After the removing step, it is desirable to perform a covering step of forming a solder portion coated with a solder material on the second surface of the glass sheet in a portion around the plurality of protrusions on which the plurality of protrusions are not formed. The substrate may be made of glass or silicon. [Effects of the Invention]

[0010] According to the glass sheet of the present invention and the manufacturing method of the present invention, it is possible to improve productivity in mass-producing dome-shaped glass caps. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view of a glass sheet according to the present invention; [Figure 2] Cross-sectional view taken along line II-II in Figure 1. [Figure 3] FIG. 2 is a schematic diagram showing a state in which the glass sheet shown in FIG. 1 is being divided. [Figure 4] (a) Schematic diagram of the divided glass sheet, (b) perspective view of the glass cap. [Figure 5] FIG. [Figure 6] FIG. 1 is a perspective view of a substrate on which a plurality of circular recesses are formed. [Figure 7] Schematic diagram showing a joining process. [Figure 8] Schematic diagram showing a protrusion forming step. [Figure 9] Schematic diagram showing the fixing process. [Figure 10] (a) Schematic diagram showing the removal process, (b) Schematic diagram of the glass sheet from which the substrate has been removed. [Figure 11] FIG. 10(a) is a schematic diagram showing a first modified example of the removal step, and FIG. 10(b) is a schematic diagram showing a second modified example of the removal step. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a glass sheet and a method for manufacturing a glass sheet according to the present invention will now be described with reference to the drawings.

[0013] First, the glass sheet according to the present invention will be described. As shown in FIGS. 1 and 2, the glass sheet 2 is a planar sheet having a plurality of protrusions 4 protruding in a dome shape. The protrusions 4 protrude toward the first surface 2a of the glass sheet 2. The diameter of each protrusion 4 is less than 50 mm when viewed in a direction perpendicular to the first surface 2a of the glass sheet 2 on which the protrusions 4 are formed. In this embodiment, the protrusions 4 are arranged in a 6×6 array (36 in total), but the number of protrusions 4 formed on the glass sheet 2 is arbitrary. As shown in FIG. 2, the second surface 2b opposite the first surface 2a of the glass sheet 2 has at least one solder portion 6 coated with a solder material in the area surrounding the protrusions 4 where no protrusions 4 are formed. In this embodiment, the number of solder portions 6 is the same as the number of protrusions 4, and the solder portions 6 are formed around each of the protrusions 4. The cross section of FIG. 2 is a plane passing through the apexes of the protrusions 4 and perpendicular to the glass sheet 2. Although the glass sheet 2 in this embodiment has a rectangular shape (for example, 100 mm×100 mm), it may have another shape such as a circle.

[0014] By dividing such a glass sheet 2 into each of the dome-shaped protrusions 4, it is possible to manufacture dome-shaped glass caps. The glass sheet 2 can be divided using, for example, a dicing device 8 shown in Figure 3. The dicing device 8 includes a chuck table 10 that holds the workpiece by suction, and a cutting blade 12 that cuts the workpiece held on the chuck table 10.

[0015] To divide the glass sheet 2, first, place the glass sheet 2 on the upper surface of the chuck table 10 with the protruding portions 4 facing upward. Next, a suction device (not shown) connected to the chuck table 10 is activated to generate suction on the upper surface of the chuck table 10, thereby suction-holding the second surface 2b of the glass sheet 2 on the upper surface of the chuck table 10. Next, the cutting blade 12 is rotated in the direction indicated by arrow R1 in FIG. 3. The cutting edge of the cutting blade 12 is then inserted between the protruding portions 4 of the glass sheet 2, and the chuck table 10, which holds the glass sheet 2 by suction, is moved along the X-axis perpendicular to the plane of the drawing, thereby cutting the glass sheet 2. This cutting process and the indexing of the cutting blade 12 along the Y-axis are repeated, and the chuck table 10 is then rotated 90 degrees, after which the cutting process and indexing are repeated. As a result, the glass sheet 2 is divided into individual protruding portions 4, producing dome-shaped glass caps 14, as shown in FIGS. 4(a) and 4(b). Therefore, the glass sheet 2 having the plurality of protruding portions 4 protruding in a dome shape can improve productivity when mass-producing the dome-shaped glass caps 14.

[0016] Next, a method for manufacturing the flat glass sheet 2 having a plurality of protruding portions 4 protruding in a dome shape on the first surface 2a will be described.

[0017] (Substrate preparation process) In this embodiment, first, a substrate preparation step is carried out to prepare a substrate 16 as shown in FIG. 4. The shape of the substrate 16 shown in FIG. 4 is rectangular, similar to the shape of the glass sheet 2, but it does not have to be the same shape as the glass sheet 2. The dimensions of the substrate 16 in a plan view are preferably equal to or greater than the dimensions of the glass sheet 2 (e.g., 100 mm × 100 mm). The thickness of the substrate 16 may be the same as or different from the thickness of the glass sheet 2. The substrate 16 is preferably made of a material (e.g., glass or silicon (Si)) having a linear expansion coefficient close to that of the glass sheet 2, and more preferably is made of the same material as the glass sheet 2.

[0018] (Circular recess formation process) After the substrate preparation step, a circular recess formation step is performed to form a plurality of circular recesses in the substrate 16. In the circular recess formation step, a required pattern is first formed on the first surface 16a of the substrate 16 by photolithography. Next, the first surface 16a of the substrate 16 on which the pattern has been formed is subjected to sandblasting, CNC (Computer Numerical Control) processing, or etching (wet etching or dry etching). As a result, a plurality of circular recesses 18 can be formed on the first surface 16a of the substrate 16, as shown in FIG. 6.

[0019] (Temporary joining process) After the circular recess forming step, as shown in FIG. 7 , a bonding step is performed in which the second surface 2b of the glass sheet 2, opposite the first surface 2a, is bonded to the substrate 16 having the plurality of circular recesses 18 formed therein. The glass sheet 2 to be temporarily bonded in the temporary bonding step is a flat sheet without the plurality of protrusions 4 formed therein. In the temporary bonding step, the substrate 16 and the glass sheet 2 can be temporarily bonded by optical contact, for example. Furthermore, after forming a bonded body 20 by temporarily bonding the substrate 16 and the glass sheet 2, it is preferable to heat the bonded body 20 to enhance adhesion between the substrate 16 and the glass sheet 2. For example, a nitrogen atmosphere furnace can be used to heat the bonded body 20. The heating temperature of the bonded body 20 may be a temperature just below the softening point of the glass sheet 2.

[0020] (Protrusion formation process) After the joining step, a protrusion forming step is performed to form multiple protrusions 4 on the glass sheet 2. The protrusion forming step can be performed using, for example, a vacuum atmosphere furnace (not shown). In the protrusion forming step, the bonded body 20 is placed in the vacuum atmosphere furnace and heated to a temperature above the softening point of the glass sheet 2. Next, the pressure inside the vacuum atmosphere furnace is reduced. This reduces the pressure around the bonded body 20, creating a pressure difference between the pressure around the bonded body 20 and the pressure inside the circular recesses 18. As a result, portions of the glass sheet 2 corresponding to the multiple circular recesses 18 protrude in a dome shape toward the first surface 2a. In this way, multiple protrusions 4 are formed on the glass sheet 2. The protrusion height of the protrusions 4 can be adjusted by controlling the temperature and pressure inside the vacuum atmosphere furnace.

[0021] (Fixed process) After the protrusion forming step, a fixing step is carried out in which the protrusions 4 of the glass sheet 2 are accommodated in a plurality of receiving holes of a jig having a plurality of receiving holes and the glass sheet 2 is fixed to the jig. The jig may have any shape as long as it can accommodate the protrusions 4 of the glass sheet 2 and fix the glass sheet 2 to the jig.

[0022] In the fixing step, for example, a jig 22 shown in FIG. 9 can be used. The jig 22 has a plurality of accommodating holes 24 that accommodate a plurality of protrusions 4. The dimensions of the accommodating holes 24 in a plan view are larger than the diameter of the protrusions 4, and the depth of the accommodating holes 24 is larger than the protruding height of the protrusions 4. Therefore, when the protrusions 4 are accommodated in the accommodating holes 24, the protrusions 4 do not come into contact with the bottom surface 24a or side surfaces 24b of the accommodating holes 24. The shape of the accommodating holes 24 can be any shape, such as circular or rectangular.

[0023] It is preferable that the jig 22 has formed therein a number of accommodating holes 24 corresponding to the number of protrusions 4. In this case, one accommodating hole 24 accommodates one protrusion 4. However, one accommodating hole 24 may accommodate two or more protrusions 4. Furthermore, the jig 22 may have one accommodating hole 24, which accommodates all of the protrusions 4.

[0024] The jig 22 can be manufactured, for example, by the same procedure as the circular recess forming process described above. That is, the jig 22 can be manufactured by forming a desired pattern by photolithography on a plate material without a receiving hole 24, and then performing sandblasting, CNC machining, or etching. The jig 22 can be made of any of carbon, silicon, glass, and ceramics, for example. Such a jig 22 can be manufactured at lower cost and in a shorter period of time than a mold for manufacturing a glass cap by a conventional molding method.

[0025] 9, in the fixing step, the plurality of protrusions 4 are accommodated in the accommodation holes 24 of the jig 22, and the glass sheet 2 is fixed to the jig 22. An appropriate adhesive can be used to fix the glass sheet 2 to the jig 22.

[0026] (Removal process) After the fixing step, a removal step is carried out in which the substrate 16 temporarily bonded to the glass sheet 2 is removed by grinding or polishing the substrate 16. The removal step can be carried out using, for example, a grinding device 26 shown in Fig. 10(a). The grinding device 26 includes a chuck table 28 that holds the workpiece, and a grinding wheel 30 that grinds the workpiece held on the chuck table 28.

[0027] In the removal process, first, the second surface 16b of the substrate 16 is faced upward, and the flat surface 22a of the jig 22 (the surface on which the accommodation hole 24 is not formed) is suction-held on the upper surface of the chuck table 28. Next, the grinding wheel 30 is rotated in the direction indicated by arrow R2 in FIG. 10(a) and lowered to bring the grinding wheel 30 into contact with the second surface 16b of the substrate 16. Then, the grinding wheel 30 is appropriately moved in the XY plane and lowered at an appropriate grinding feed rate. As a result, the substrate 16 can be ground and removed from the bonded body 20, as shown in FIG. 10(b).

[0028] The device for removing the substrate 16 is not limited to the grinding device 26. For example, as shown in FIG. 11(a), a grinding device 26' having a grinding wheel 32 larger than the substrate 16 can be used. Alternatively, as shown in FIG. 11(b), a grinding device 26'' having a grinding wheel 34 whose axis extends horizontally can be used. Furthermore, the substrate 16 can be removed from the bonded body 20 by polishing the substrate 16 with a polishing device (not shown) having a polishing pad.

[0029] (Coating process) After the removing step, a coating step is performed to form solder portions 6 coated with a solder material on the portions of the second surface 2b of the glass sheet 2 surrounding the plurality of protrusions 4 where the plurality of protrusions 4 are not formed. In the coating step, at least one solder portion 6 is formed. In the coating step of this embodiment, the same number of solder portions 6 as the number of protrusions 4 are formed, and multiple solder portions 6 are formed around each of the plurality of protrusions 4. The solder portions 6 can be formed on the second surface 2b of the glass sheet 2 by vapor deposition or plating. The coating step may be performed before or after the glass sheet 2 is removed from the jig 22.

[0030] In this embodiment, the solder portions 6 are formed on the glass sheet 2 before it is divided into the glass caps 14. Therefore, the manufacturing method of this embodiment has better productivity than the conventional processing method in which the solder portions 6 are formed on a chip-by-chip basis.

[0031] As described above, a glass sheet 2 (see FIGS. 1 and 2) having a plurality of dome-shaped protrusions 4 is manufactured. Then, by dividing the glass sheet 2 into each dome-shaped protrusion 4, dome-shaped glass caps 14 can be manufactured. This allows for improved productivity in mass-producing the glass caps 14.

[0032] In this embodiment, unlike conventional molding methods, no mold is required to manufacture the glass cap 14, making it easy to change the shape and dimensions of the glass cap 14. Furthermore, in conventional molding methods, the minimum size of a glass cap that can be manufactured is approximately 50 mm square due to the difference in the linear expansion coefficient between the mold material and the glass cap material. In this regard, if the substrate 16 of this embodiment is made of a material (e.g., glass or silicon (Si)) having a linear expansion coefficient close to that of the glass sheet 2, the glass cap 14 can be made smaller than in conventional molding methods.

[0033] Furthermore, in this embodiment, the protrusion height of the protrusion 4 on the glass sheet 2 (i.e., the height of the glass cap 14) can be adjusted by controlling the temperature and pressure in the protrusion formation process. This makes it possible to form an anti-reflection film on the glass cap 14, thereby improving the light extraction efficiency. [Explanation of symbols]

[0034] 2: glass sheet, 2a: first surface of glass sheet, 2b: second surface of glass sheet, 4: protrusion, 6: solder material, 14: glass cap, 16: substrate, 16a: first surface of substrate, 16b: second surface of substrate, 18: circular recess, 22: jig, 24: accommodation hole

Claims

1. A method for manufacturing a flat glass sheet having a plurality of dome-shaped protrusions on a first surface, comprising: a temporary bonding step of temporarily bonding a second surface of the glass sheet opposite the first surface to a substrate having a plurality of circular recesses formed thereon by optical contact; a protrusion forming process in which the glass sheet and the substrate are heated to a temperature higher than the softening point of the glass sheet and the pressure around the glass sheet and the substrate is reduced, thereby causing portions of the glass sheet corresponding to the plurality of circular recesses to protrude in the dome shape toward the first surface of the glass sheet, thereby forming the plurality of protrusions on the glass sheet; a removing step of removing the substrate temporarily bonded to the glass sheet by grinding or polishing the substrate temporarily bonded to the glass sheet.

2. 2. The method for manufacturing a glass sheet according to claim 1, wherein after the removal process, a coating process is carried out in which a solder portion having a surface made of a solder material is formed on the second surface of the glass sheet in a portion around the plurality of protrusions where the plurality of protrusions are not formed.

3. The method for manufacturing a glass sheet according to claim 1 or 2, wherein the substrate is made of glass or silicon.

4. A method for manufacturing a glass cap, which, after carrying out the coating process in the method for manufacturing a glass sheet described in claim 2, produces a dome-shaped glass cap by dividing the glass sheet into each protrusion before soldering using the solder portion.

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