Adhesives, fixing methods, and processing methods

Abstract

It is possible to suppress the decrease in processing efficiency. [Solution] The processing method is a method for processing a workpiece and comprises: an adhesive preparation step 101 in which an adhesive is prepared by adding a polymerization initiator, which is initiated by irradiation with light, to a composition consisting of epoxy resin, oxetane resin, and a reactive diluent; an application step 102 in which the adhesive is applied to at least one of a substrate and a workpiece; an irradiation step 103 in which light is irradiated onto the adhesive; a fixing step 104 in which, after performing the irradiation step 103, the adhesive is interposed between the substrate and the workpiece to fix the workpiece on the substrate; a holding step 105 in which the substrate side is held by a holding unit to expose the workpiece; and a processing step 106 in which the workpiece, which is exposed while the substrate side is held by the holding unit, is processed.

Description

Technical Field

[0001] The present invention relates to an adhesive, a fixing method using the adhesive, and a processing method of a workpiece fixed by the fixing method using the adhesive.

Background Art

[0002] In some cases, processing such as grinding and cutting is performed on a wafer in a state where the wafer is attached to a rigid substrate (see, for example, Patent Document 1 and Patent Document 2).

[0003] Hot melt type wax that softens by heating is widely used to firmly attach the wafer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when attaching, a heat source for heating to about 60 ° C to 80 ° C such as a hot plate is required, and after heating and softening for attachment, it takes several hours until cooling and curing, and the processing efficiency tends to decrease, and improvement is eagerly desired.

[0006] An object of the present invention is to provide an adhesive, a fixing method, and a processing method capable of suppressing a decrease in processing efficiency.

Means for Solving the Problems

[0007] To solve the above-mentioned problems and achieve the objective, the adhesive of the present invention is an adhesive for bonding adherends, characterized in that a composition comprising an epoxy resin, an oxetane resin, and a reactive diluent contains a polymerization initiator that initiates polymerization upon irradiation with light.

[0008] The adhesive may further contain a light-absorbing material that absorbs light of a different wavelength than the light that initiates polymerization.

[0009] The present invention relates to a method for fixing a workpiece, comprising: an adhesive preparation step of preparing an adhesive comprising a composition of epoxy resin, oxetane resin, and a reactive diluent, and a polymerization initiator that initiates polymerization upon irradiation with light; an application step of applying the adhesive to at least one of a substrate and a workpiece; an irradiation step of irradiating the adhesive with light; and a fixing step of, after performing the irradiation step, interposing the adhesive between the substrate and the workpiece to fix the workpiece on the substrate.

[0010] In the aforementioned fixing method, the substrate may be made of a silicon wafer.

[0011] The present invention relates to a method for processing a workpiece, comprising: an adhesive preparation step of preparing an adhesive comprising a composition of epoxy resin, oxetane resin, and a reactive diluent, and a polymerization initiator that initiates polymerization upon irradiation with light; an application step of applying the adhesive to at least one of a substrate and a workpiece; an irradiation step of irradiating the adhesive with light; a fixing step of fixing the workpiece on the substrate by interposing the adhesive between the substrate and the workpiece after performing the irradiation step; a holding step of holding the substrate side with a holding unit to expose the workpiece; and a processing step of processing the workpiece which is exposed and held on the substrate side by the holding unit.

[0012] The processing method may further include a light-absorbing material that absorbs a second light of a different wavelength than the first light, and after performing the processing step, a removal step of irradiating the adhesive with the second light to remove the workpiece from the substrate.

[0013] In the above processing method, the workpiece may be ground with a grinding wheel in the processing step.

[0014] In the above processing method, the workpiece may be cut with a cutting blade in the processing step.

[0015] In the processing method described above, a laser beam may be irradiated onto the workpiece during the processing step. [Effects of the Invention]

[0016] This invention has the effect of suppressing a decrease in processing efficiency. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a schematic perspective view showing the workpiece to be processed by the processing method according to Embodiment 1. [Figure 2] Figure 2 is a schematic perspective view showing the substrate to which the workpiece shown in Figure 1 is bonded. [Figure 3] Figure 3 is a flowchart showing the flow of the processing method according to Embodiment 1. [Figure 4] Figure 4 is a schematic side view showing a partial cross-section of the coating step of the processing method shown in Figure 3. [Figure 5] Figure 5 is a schematic side view showing a partial cross-section of the irradiation step of the processing method shown in Figure 3. [Figure 6] Figure 6 is a schematic side view showing a partial cross-section of the state in which the surface of the workpiece is facing the adhesive on the substrate during the fixing step of the processing method shown in Figure 3. [Figure 7]FIG. 7 is a side view schematically showing in partial cross-section a state where a workpiece is adhered to a substrate via an adhesive in the fixing step of the processing method shown in FIG. 3. [Figure 8] FIG. 8 is a cross-sectional view schematically showing the holding step of the processing method shown in FIG. 3. [Figure 9] FIG. 9 is a side view schematically showing in partial cross-section the processing step of the processing method shown in FIG. 3. [Figure 10] FIG. 10 is a side view schematically showing in partial cross-section the removal step of the processing method shown in FIG. 3. [Figure 11] FIG. 11 is a side view schematically showing in partial cross-section the coating step of the processing method according to Modification 1 of Embodiment 1. [Figure 12] FIG. 12 is a side view schematically showing in partial cross-section the irradiation step of the processing method according to Modification 1 of Embodiment 1. [Figure 13] FIG. 13 is a cross-sectional view schematically showing a state where the surface of a workpiece is faced to an adhesive on a substrate in the fixing step of the processing method according to Modification 1 of Embodiment 1. [Figure 14] FIG. 14 is a cross-sectional view schematically showing a state where a workpiece is adhered to a substrate via an adhesive in the fixing step of the processing method according to Modification 1 of Embodiment 1. [Figure 15] FIG. 15 is a side view schematically showing in partial cross-section the processing step of the processing method according to Modification 2 of Embodiment 1. [Figure 16] FIG. 16 is a side view schematically showing in partial cross-section the removal step of the processing method according to Modification 2 of Embodiment 1. [Figure 17] FIG. 17 is a side view schematically showing in partial cross-section the processing step of the processing method according to Modification 3 of Embodiment 1. [Figure 18] FIG. 18 is a side view schematically showing in partial cross-section the removal step of the processing method according to Modification 3 of Embodiment 1.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] Embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by those skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the present invention.

[0019] [Embodiment 1] The processing method according to Embodiment 1 of the present invention will be described with reference to the drawings. Figure 1 is a schematic perspective view showing the workpiece to be processed by the processing method according to Embodiment 1. Figure 2 is a schematic perspective view showing the substrate to which the workpiece shown in Figure 1 is bonded. Figure 3 is a flowchart showing the flow of the processing method according to Embodiment 1.

[0020] (Workpiece) The processing method according to Embodiment 1 is a method of processing the workpiece 1 (corresponding to the adherend) shown in Figure 1 by bonding it to the substrate 10 shown in Figure 2. The workpiece 1 to be processed in the processing method according to Embodiment 1 is, for example, a disc-shaped semiconductor wafer or an optical device wafer with silicon, sapphire, gallium, or SiC as the substrate 2.

[0021] As shown in Figure 1, the workpiece 1 has multiple intersecting division lines 4 set on its surface 3, and devices 5 are formed in each region partitioned in a grid pattern by the division lines 4 on the surface 3.

[0022] Device 5 is, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), or a memory (semiconductor memory device). The workpiece 1 is divided into individual devices 5 along the division line 4. Furthermore, in this invention, the workpiece 1 is not limited to the wafer shown in Figure 1.

[0023] (substrate) The substrate 10 shown in Figure 2 to which the workpiece 1 is bonded is a disc-shaped wafer made of silicon, glass, or ceramics. In the present invention, the substrate 10 is not limited to a disc shape, but may be formed in a rectangular shape, for example. In Embodiment 1, the substrate 10 is made of silicon, which is less expensive than a substrate made of glass, and is a bare silicon wafer on which no devices are formed. Also in Embodiment 1, the outer diameter of the substrate 10 is the same as the outer diameter of the workpiece 1.

[0024] (Processing method) The processing method according to Embodiment 1, as shown in Figure 3, comprises an adhesive preparation step 101, an application step 102, an irradiation step 103, a fixing step 104, a holding step 105, a processing step 106, and a removal step 107.

[0025] (Adhesive preparation step) The adhesive preparation step 101 is a step in which an adhesive 20 (shown in Figure 4, etc.) is prepared to bond the workpiece 1 shown in Figure 1, which is the adherend, to the substrate 10 shown in Figure 2. The adhesive 20 prepared in the adhesive preparation step 101 is a liquid so-called ultraviolet (UV) curing resin that hardens when irradiated with ultraviolet light 35 (shown in Figure 5).

[0026] In Embodiment 1, the adhesive 20 is a liquid resin comprising an epoxy resin, an oxetane resin, and a reactive diluent, with a photopolymerization initiator (equivalent to a polymerization initiator) added, which initiates polymerization upon irradiation with ultraviolet light 35. The adhesive 20 contains 50% to 70% by weight of epoxy resin, 10% to 30% by weight of reactive diluent, 5% to 9% by weight of oxetane resin, and 0.1% to 2% by weight of photopolymerization initiator. The epoxy resin consists of a polyfunctional epoxy resin and a monofunctional epoxy resin, and the ratio of polyfunctional epoxy to monofunctional epoxy is in the range of 3:7 to 9:1, and is appropriately selected according to the applicability and the desired thickness of the adhesive layer.

[0027] Furthermore, epoxy resins, when alone, do not undergo polymerization reactions and harden easily even when irradiated with UV-35 light. For this reason, even if epoxy resins contain a photopolymerization initiator, their polymerization reaction rate under UV-35 irradiation is slower and their reaction rate is lower than that of thermosetting resins and other UV-curing resins.

[0028] In Embodiment 1, since the adhesive 20 contains an oxetane resin in addition to the epoxy resin, the reaction rate is accelerated after a certain amount of polymerization of the composition has progressed following irradiation with ultraviolet light 35. Furthermore, in Embodiment 1, the adhesive 20 contains a reaction diluent that slows down the polymerization reaction of the composition and delays the time until the polymerization reaction begins after irradiation with ultraviolet light 35.

[0029] For this reason, the time it takes for adhesive 20 to begin curing after irradiation with ultraviolet light 35 is longer than that of other ultraviolet-curing resins. By appropriately setting the ratio of reactive diluent and oxetane resin to epoxy resin, the time from irradiation with ultraviolet light 35 until the polymerization reaction begins, and the time until the polymerization reaction progresses and complete curing can be controlled, thereby improving the workability of the bonding work on the workpiece 1. For example, in Embodiment 1, adhesive 20 hardens approximately 3 to 5 minutes after irradiation with ultraviolet light 35. In Embodiment 1, in adhesive preparation step 101, adhesive 20 with the above-described configuration is prepared.

[0030] (Application step) Figure 4 is a schematic side view showing a partial cross-section of the coating step of the processing method shown in Figure 3. The coating step 102 is the step of applying adhesive 20 to at least one of the substrate 10 and the workpiece 1.

[0031] In Embodiment 1, during the coating step 102, the bonding device 30 shown in Figure 4 holds one circular surface 16 of the substrate 10 by suction to the holding surface 32 of the spinner table 31, rotates the spinner table 31 around its axis, and simultaneously drops liquid adhesive 20 from the coating nozzle 33 onto the center of the other circular surface 13 of the substrate 10.

[0032] The dropped adhesive 20 flows from the center to the outer edge on the other surface 13 of the substrate 10 due to the centrifugal force generated by the rotation of the spinner table 31, and is applied to the entire surface 13 of the other surface 13 of the substrate 10. Thus, in Embodiment 1, in the application step 102, the adhesive device applies the adhesive 20 to the substrate 10 by spin coating. However, in the present invention, in the application step 102, the adhesive device 30 may apply the adhesive 20 to the surface 3 of the workpiece 1 by spin coating.

[0033] (Irradiation step) Figure 5 is a schematic side view showing a partial cross-section of the irradiation step of the processing method shown in Figure 3. Irradiation step 103 is a step in which ultraviolet light 35 is irradiated onto the adhesive 20 applied to the substrate 10.

[0034] In Embodiment 1, in irradiation step 103, the bonding apparatus 30 stops rotating the spinner table 31 around its axis and faces the ultraviolet irradiation unit 34 toward the adhesive 20 applied to the substrate 10. In Embodiment 1, in irradiation step 103, the bonding apparatus 30 irradiates the adhesive 20 with ultraviolet light 35 from the ultraviolet irradiation unit 34, as shown in Figure 5. In Embodiment 1, in coating step 102, because the adhesive 20 has the configuration described above, curing immediately after irradiation with ultraviolet light 35 is suppressed.

[0035] (Fixed step) Figure 6 is a schematic side view in partial cross-section showing the state in which the surface of the workpiece is facing the adhesive on the substrate during the fixing step of the processing method shown in Figure 3. Figure 7 is a schematic side view in partial cross-section showing the state in which the workpiece is bonded to the substrate via the adhesive during the fixing step of the processing method shown in Figure 3.

[0036] The fixing step 104 is a step in which, after the irradiation step 103 is performed, adhesive 20 is interposed between the substrate 10 and the workpiece 1 to fix the workpiece 1 onto the substrate 10. In Embodiment 1, in fixing step 104, the bonding device 30 holds the workpiece 1 by suction on the lower surface 37 of the holding pad 36, and the back surface 6 of the back side of the surface 3 is brought into contact with the adhesive 20 applied to the substrate 10 on the spinner table 31, as shown in Figure 6. In Embodiment 1, in fixing step 104, the bonding device 30 lowers the holding pad 36 and presses the surface 3 of the workpiece 1 against the adhesive 20 on the substrate 10, as shown in Figure 7, and the adhesive 20 hardens, bonding the workpiece 1 to the substrate 10.

[0037] The aforementioned adhesive preparation step 101, application step 102, irradiation step 103, and fixing step 104 constitute a method for fixing the workpiece 1 to the substrate 10.

[0038] (Holding step) Figure 8 is a schematic cross-sectional view showing the holding step of the processing method shown in Figure 3. Holding step 105 is a step in which the substrate 10 is held by the holding unit 41 to expose the workpiece 1. In Embodiment 1, in holding step 105, the grinding device 40 shown in Figure 8 places one side 16 of the substrate 10 on the holding surface 42 of the holding unit 41. In Embodiment 1, in holding step 105, as shown in Figure 8, the grinding device 40 opens the on / off valve 43 and uses the suction force from the suction source 44 to suction and hold the substrate 10 on the holding surface 42, exposing the back side 6 of the workpiece 1.

[0039] (Processing step) Figure 9 is a schematic side view showing a partial cross-section of the processing steps of the processing method shown in Figure 3. Processing step 106 is a step in which the workpiece 1, which is exposed and held on the substrate 10 side by the holding unit 41, is processed.

[0040] In Embodiment 1, in processing step 106, the grinding device 40, as shown in Figure 9, rotates the grinding wheel 46 around its axis using the spindle 45 and rotates the holding unit 41 around its axis while supplying grinding water, and brings the grinding wheel 47 into contact with the back surface 6 of the workpiece 1 and brings it closer to the holding unit 41 at a predetermined feed rate, thereby grinding the back surface 6 of the workpiece 1 with the grinding wheel 47 and thinning the workpiece 1 to the finished thickness. Thus, in Embodiment 1, in processing step 106, the workpiece 1 is ground with the grinding wheel 46.

[0041] (Removal step) Figure 10 is a schematic side view showing a partial cross-section of the removal step of the processing method shown in Figure 3. The removal step 107 is a step in which, after performing the processing step 106, the adhesive 20 is irradiated with infrared light 56, which is a second light, to remove the workpiece 1 from the substrate 10.

[0042] In Embodiment 1, in the removal step 107, the separation device 50 shown in Figure 10 places the back surface 6 of the workpiece 1 on the holding surface 52 of the holding unit 51. In Embodiment 1, in the removal step 107, as shown in Figure 10, the separation device 50 opens the on / off valve 53 and uses the suction force from the suction source 54 to suck and hold the workpiece 1 on the holding surface 52, exposing one side 16 of the substrate 10.

[0043] In Embodiment 1, in the removal step 107, the separation device 50, as shown in Figure 10, positions a focal point 57 of infrared light 56, which has a different wavelength from ultraviolet light 35 (which is light that is transparent to the substrate 10 irradiated by the irradiation unit 55 and absorbed by the adhesive 20, and initiates polymerization), on the adhesive 20, and moves the holding unit 41 and the irradiation unit 55 relative to each other to irradiate the entire surface of the adhesive 20 with infrared light 56. In Embodiment 1, in the removal step 107, the infrared light 56, which is the second light irradiated by the irradiation unit 55 of the separation device 50, is, for example, an infrared laser, which is light for peeling off the adhesive 20, and is light with a different wavelength from ultraviolet light 35 (which is light that initiates polymerization of the adhesive 20). The irradiation unit 55 of the separation device 50 has an oscillator that emits infrared light 56 ​​and a condenser that focuses the infrared light 56.

[0044] In Embodiment 1, in the removal step 107, since the infrared rays 56 have wavelengths that are absorbed by the adhesive 20, the separation device 50 melts or evaporates the adhesive 20 by irradiation with infrared rays 56 and removes the workpiece 1 from the substrate 10. In Embodiment 1, in the removal step 107, as shown in Figure 10, the separation device 50 rotates the holding unit 41 around its axis while moving the irradiation unit 55 horizontally, irradiating the adhesive 20 with infrared rays 56 in a spiral pattern.

[0045] However, in the present invention, in the removal step 107, the infrared rays 56 may be irradiated onto the adhesive 20 in a concentric or linear manner by repeatedly performing processing feed and indexing feed. In the present invention, in the removal step 107, it is preferable that the focal point 57 of the infrared rays 56 irradiated onto the adhesive 20 overlaps with the entire area of ​​the adhesive 20 to be removed.

[0046] The processing method according to Embodiment 1 described above involves bonding the workpiece 1 to the substrate 10 using a liquid adhesive 20 which contains a photopolymerization initiator in a composition comprising epoxy resin, oxetane resin, and a reactive diluent, and which hardens when irradiated with ultraviolet light 35.

[0047] Thus, the processing method according to Embodiment 1 allows the adhesive 20 to be cured by irradiation with ultraviolet light 35, making it easier to work with and allowing curing in a shorter time compared to hot-melt type wax.

[0048] As a result, the processing method according to Embodiment 1 has the effect of significantly reducing the time required to bond the workpiece 1 to the substrate 10 compared to using hot-melt wax, thereby suppressing a decrease in processing efficiency.

[0049] Furthermore, in the processing method according to Embodiment 1, the adhesive 20 does not harden immediately upon irradiation with ultraviolet light 35, but hardens after a certain period of time (for example, about 3 to 5 minutes), so the parts can be bonded together after irradiation with ultraviolet light 35. In other words, it is suitable for substrates and workpieces 1 that do not transmit ultraviolet light 35, and a more inexpensive silicon wafer can be used as the substrate 10 instead of a glass substrate.

[0050] Furthermore, since the processing method according to Embodiment 1 uses an epoxy resin-based adhesive 20 to bond the workpiece 1 to the substrate 10, the workpiece 1 can be fixed more firmly to the substrate 10 than when using hot-melt wax or acrylic adhesive.

[0051] As described above, the processing method according to Embodiment 1 allows the workpiece 1 to be fixed more firmly to the substrate 10 than when using hot-melt wax or acrylic adhesive. Therefore, during processing such as grinding or cutting, sinking of the workpiece 1 due to processing load can be prevented, and chipping and cracking of the workpiece 1 can be suppressed.

[0052] Furthermore, adhesives that require mixing two components to cure are difficult to mix uniformly, which may lead to inconsistencies in fixing at the bonding surface. However, the processing method according to Embodiment 1 uses the aforementioned adhesive 20, thus suppressing the occurrence of inconsistencies in fixing.

[0053] [Variation 1] Next, a processing method according to Modification 1 of Embodiment 1 will be described based on the drawings. Figure 11 is a schematic side view showing a partial cross-section of the coating step of the processing method according to Modification 1 of Embodiment 1. Figure 12 is a schematic side view showing a partial cross-section of the irradiation step of the processing method according to Modification 1 of Embodiment 1. Figure 13 is a schematic cross-sectional view showing the state in which the surface of the workpiece is facing the adhesive on the substrate during the fixing step of the processing method according to Modification 1 of Embodiment 1. Figure 14 is a schematic cross-sectional view showing the state in which the workpiece is bonded to the substrate via the adhesive during the fixing step of the processing method according to Modification 1 of Embodiment 1. Note that Figures 11, 12, 13, and 14 use the same reference numerals as Embodiment 1 for the same parts and their descriptions are omitted.

[0054] The processing method according to Modification 1 is the same as that of Embodiment 1, except that the coating step 102, the irradiation step 103, and the fixing step 104 are different from those of Embodiment 1.

[0055] In Modification 1, during the coating step 102, the adhesive device 60 shown in Figure 11 places one side 16 of the substrate 10 onto the holding surface 62 of the holding unit 61. In Embodiment 1, during the coating step 102, as shown in Figure 11, the adhesive device 60 opens the on / off valve 63 and uses the suction force from the suction source 64 to suction and hold the substrate 10 to the holding surface 62. In Modification 1, during the coating step 102, the adhesive device 60 shown in Figure 11 drops liquid adhesive 20 from the coating nozzle 65 onto the center of the other circular surface 13 of the substrate 10.

[0056] In Modification 1, in irradiation step 103, the bonding device 60 faces the ultraviolet irradiation unit 66 toward the adhesive 20 applied to the substrate 10. In Modification 1, in irradiation step 103, the bonding device 60 irradiates the adhesive 20 with ultraviolet light 35 from the ultraviolet irradiation unit 66, as shown in Figure 12.

[0057] In Modified Example 1, in fixing step 104, the bonding device 60 opens the on / off valve 69 and uses the suction force from the suction source 70 to hold the workpiece 1 against the lower surface 68 of the holding pad 67 by suction, so that the back surface 6 of the workpiece 1's surface 3 faces the adhesive 20 applied to the substrate 10 on the holding unit 61, as shown in Figure 13. In Modified Example 1, in fixing step 104, the bonding device 60 lowers the holding pad 67 and presses the surface 3 of the workpiece 1 against the adhesive 20 on the substrate 10, as shown in Figure 14, so that the adhesive 20 spreads to the outer circumference of the substrate 10 and the workpiece 1, and the workpiece 1 is bonded to the substrate 10 by the curing of the adhesive 20.

[0058] The processing method according to Modification 1 involves bonding the workpiece 1 to the substrate 10 using a liquid adhesive 20 which contains a photopolymerization initiator in a composition comprising epoxy resin, oxetane resin, and a reactive diluent, and hardens when irradiated with ultraviolet light 35. Similar to Embodiment 1, this method significantly reduces the time required to bond the workpiece 1 to the substrate 10 compared to using hot-melt wax, thus suppressing a decrease in processing efficiency. Furthermore, in Modification 1, similar to Embodiment 1, the workpiece 1 may be fixed to the substrate 10 by applying the adhesive 20 to the surface 3 of the workpiece 1.

[0059] [Variation 2] Next, the processing method according to Modification 2 of Embodiment 1 will be described based on the drawings. Figure 15 is a schematic side view showing a partial cross-section of the processing steps of the processing method according to Modification 2 of Embodiment 1. Figure 16 is a schematic side view showing a partial cross-section of the removal step of the processing method according to Modification 2 of Embodiment 1. Note that Figures 15 and 16 use the same reference numerals as Embodiment 1 for the same parts and their descriptions are omitted.

[0060] The processing method according to the modified example 2 is the same as that of Embodiment 1, except that processing step 106 and removal step 107 are different from those of Embodiment 1.

[0061] In Modified Example 2, in processing step 106, as shown in Figure 15, the cutting device 80 opens the on / off valve 83 in the holding step 105 and uses the suction force from the suction source 84 to suction and hold the substrate 10 to the holding surface 82 of the holding unit 81, exposing the back surface 6 of the workpiece 1. Then, an infrared camera images the substrate 10 from the back surface 6 of the workpiece 1 to detect the division line 4. In Modified Example 2, in processing step 106, as shown in Figure 15, the cutting device 80 moves the cutting blade 85, which is rotated around its axis by a spindle, and the workpiece 1 relatively along the division line 4, cutting the workpiece 1 with the cutting blade 85 by cutting into the division line 4 from the back surface 6 until it reaches the adhesive 20.

[0062] In Modified Example 2, in processing step 106, the cutting device 80 cuts all the planned division lines 4 of the workpiece 1, dividing the workpiece 1 into individual devices 5. Thus, in Modified Example 2, in processing step 106, the workpiece 1 is cut with a cutting blade 85.

[0063] In Modified Example 2, in the removal step 107, a disc-shaped tape 7 (shown in Figure 16) with a larger diameter than the workpiece 1 is attached to the back surface 6 of the workpiece 1, and a ring-shaped frame 8 is attached to the outer edge of the tape 7. In Modified Example 2, in the removal step 107, the separation device 50 uses suction to hold the back surface 6 of the workpiece 1 to the holding surface 52 of the holding unit 51 via the tape 7, and clamps the frame 8 with a clamp portion 58 located on the outer circumference of the holding surface 52.

[0064] In the modified example 2, in the removal step 107, the separation device 50, as shown in Figure 16, positions the focusing point 57 on the adhesive 20, similar to the embodiment 1, and irradiates the adhesive 20 with infrared light 56 ​​from the irradiation unit 55 through the substrate 10 to melt or evaporate the adhesive 20.

[0065] The processing method according to the modified example 2 involves bonding the workpiece 1 to the substrate 10 using a liquid adhesive 20 which contains a photopolymerization initiator in a composition comprising epoxy resin, oxetane resin, and a reactive diluent, and hardens when irradiated with ultraviolet light 35. Similar to embodiment 1, this method significantly reduces the time required to bond the workpiece 1 to the substrate 10 compared to using hot-melt wax, thus suppressing a decrease in processing efficiency.

[0066] [Example 3] Next, the processing method according to Modification 3 of Embodiment 1 will be described based on the drawings. Figure 17 is a schematic side view showing a partial cross-section of the processing steps of the processing method according to Modification 3 of Embodiment 1. Figure 18 is a schematic side view showing a partial cross-section of the removal step of the processing method according to Modification 3 of Embodiment 1. Note that Figures 17 and 18 use the same reference numerals as Embodiment 1 for the same parts and their descriptions are omitted.

[0067] The processing method according to Modification 3 is the same as that of Embodiment 1, except that processing step 106 and removal step 107 are different from those of Embodiment 1.

[0068] In Modified Example 3, in processing step 106, as shown in Figure 17, the laser processing apparatus 90 opens the on / off valve 93 in holding step 105 and uses the suction force from the suction source 94 to suction and hold the substrate 10 to the holding surface 92 of the holding unit 91, exposing the back surface 6 of the workpiece 1. Then, an infrared camera images the substrate 10 from the back surface 6 of the workpiece 1 to detect the division line 4. In Modified Example 3, in processing step 106, as shown in Figure 17, the laser processing apparatus 90 moves the laser beam irradiation unit 95 and the workpiece 1 relative to each other along the division line 4, sets the focal point 97 inside the workpiece 1, and irradiates the workpiece 1 with a laser beam 96 of a wavelength that is transparent to the workpiece 1 from the laser beam irradiation unit 95 to laser process the workpiece 1.

[0069] In Modified Example 3, in processing step 106, the laser processing apparatus 90 forms a modified layer 9 (shown in Figure 18) inside the workpiece 1 along all of the planned division lines 4 of the workpiece 1. The modified layer 9 refers to a region in which the density, refractive index, mechanical strength, and other physical properties are different from those of the surrounding area, and examples include a melted region, a cracked region, a dielectric breakdown region, a refractive index change region, and a region in which these regions are mixed. Furthermore, the modified layer 9 has lower mechanical strength, etc., than other parts of the workpiece 1. Thus, in Modified Example 3, in processing step 106, the workpiece 1 is irradiated with a laser beam.

[0070] In Modification 3, in the removal step 107, a disc-shaped tape 7 (shown in Figure 18) with a larger diameter than the workpiece 1 is attached to the back surface 6 of the workpiece 1, and a ring-shaped frame 8 is attached to the outer edge of the tape 7. In Modification 3, in the removal step 107, the separation device 50 uses suction to hold the back surface 6 of the workpiece 1 to the holding surface 52 of the holding unit 51 via the tape 7, and clamps the frame 8 with a clamp portion 58 located on the outer circumference of the holding surface 52.

[0071] In the modified example 3, in the removal step 107, the separation device 50, as shown in Figure 18, positions the focusing point 57 on the adhesive 20, similar to the embodiment 1, and irradiates the adhesive 20 with infrared rays 56 from the irradiation unit 55 through the substrate 10 to melt or evaporate the adhesive 20.

[0072] The processing method according to Modification 3 involves bonding the workpiece 1 to the substrate 10 using a liquid adhesive 20 which contains a photopolymerization initiator in a composition comprising epoxy resin, oxetane resin, and a reactive diluent, and hardens when irradiated with ultraviolet light 35. Similar to Embodiment 1, this method significantly reduces the time required to bond the workpiece 1 to the substrate 10 compared to using hot-melt wax, thus suppressing a decrease in processing efficiency.

[0073] In the modified example 3, in the processing step 106, a modified layer 9 may be formed inside the workpiece 1, and after attaching the tape 7, the tape 7 may be expanded to divide the workpiece 1 into individual devices 5, or a gap may be formed between the divided devices 5.

[0074] In Modification 2 and Modification 3, the coating step 102, the irradiation step 103, and the fixing step 104 may be carried out in the same manner as in Modification 1.

[0075] [Variation 4] Next, the processing method according to Modification 4 of Embodiment 1 will be described based on the drawings. The processing method according to Modification 4 is the same as that of Embodiment 1, except that the adhesive 20 prepared in the adhesive preparation step 101 is different.

[0076] In modified example 4, the adhesive 20 is a liquid resin comprising an epoxy resin, an oxetane resin, and a reactive diluent, a polymerization initiator whose polymerization is initiated by irradiation with ultraviolet light 35, and an infrared light absorber which absorbs infrared light 56, a second light with a different wavelength from ultraviolet light 35, which initiates polymerization. The adhesive 20 is composed of 50% to 70% by weight of epoxy resin, 10% to 30% by weight of reactive diluent, 5% to 9% by weight of oxetane resin, 0.1% to 2% by weight of photopolymerization initiator, and 0.1% to 2% by weight of infrared light absorber which absorbs infrared light 56. The epoxy resin consists of a polyfunctional epoxy resin and a monofunctional epoxy resin, and the ratio of polyfunctional epoxy to monofunctional epoxy is in the range of 3:7 to 9:1, and is appropriately selected according to the applicability and the desired layer thickness of the adhesive. Infrared light-absorbing materials include, for example, pigments and dyes that absorb infrared light.

[0077] In other words, the processing method and adhesive 20 according to Modified Example 4 are the same as those in Embodiment 1, except that they contain an infrared light absorbing material.

[0078] The processing method according to Modification 4 involves bonding the workpiece 1 to the substrate 10 using a liquid adhesive 20 which contains a photopolymerization initiator in a composition comprising epoxy resin, oxetane resin, and a reactive diluent, and hardens when irradiated with ultraviolet light 35. Similar to Embodiment 1, this method significantly reduces the time required to bond the workpiece 1 to the substrate 10 compared to using hot-melt wax, thus suppressing a decrease in processing efficiency.

[0079] Furthermore, the processing method according to Modification 4 has the effect that, since the adhesive 20 contains an infrared light absorbing material, the adhesive 20 can be reliably melted or evaporated in the removal step 107, and the workpiece 1 can be reliably separated from the substrate 10.

[0080] In Modification 4, the coating step 102, irradiation step 103, and fixing step 104 may be performed in the same manner as in Modification 1, and the processing step 106 and removal step 107 may be performed in the same manner as in Modification 2 or Modification 3.

[0081] Next, the inventors of the present invention confirmed the effects of the processing method according to Embodiment 1. The results are shown in Table 1 below.

[0082] [Table 1]

[0083] The results are shown in Table 1. In the verification, the processing efficiency (time required to fix the workpiece 1 to the substrate 10), processing accuracy in processing step 106, and cost were confirmed for the present invention, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0084] The present invention shows an example in which a workpiece 1 is fixed to a substrate 10 using the adhesive 20 according to Embodiment 1, wherein the adhesive 20 contains 60% by weight of a polyfunctional epoxy resin and a monofunctional epoxy resin combined, 30% by weight of a reactive diluent, 8% by weight of an oxetane resin, and 2% by weight of a photopolymerization initiator. Comparative Example 1 shows an example in which a workpiece 1 is fixed to a substrate 10 using a hot-melt type wax, Comparative Example 2 shows an example in which a workpiece 1 is fixed to a substrate 10 using an acrylic adhesive, and Comparative Example 3 shows an example in which a workpiece 1 is fixed to a substrate 10 using an ultraviolet-curing type adhesive.

[0085] According to Table 1, Comparative Example 1 required a heat source to heat to approximately 60°C to 80°C, and after heating and softening the hot-melt wax and applying it, it took several hours to cool and harden, resulting in reduced processing efficiency. Comparative Examples 1 and 2 could not fix the workpiece 1 to the substrate 10 more firmly than the present invention and Comparative Example 3, causing the workpiece 1 to sink during processing step 106, resulting in reduced processing accuracy. Comparative Example 3 required the use of a glass substrate, which is more expensive than the silicon substrate 10, in order to irradiate the adhesive 20 with ultraviolet light 35 through the substrate, leading to increased costs.

[0086] Compared to Comparative Examples 1, 2, and 3 described above, Table 1 shows that the present invention can fix the workpiece 1 to the substrate 10 in less than a few hours, improving processing efficiency. It can also fix the workpiece 1 more firmly to the substrate 10 than acrylic adhesives or hot-melt waxes. Furthermore, it can suppress sinking of the workpiece 1 during processing step 106, resulting in higher processing accuracy. In addition, Table 1 shows that the present invention can use a substrate 10 made of silicon, which is less expensive than a glass substrate, thus suppressing cost increases.

[0087] Therefore, as shown in Table 1, by fixing the workpiece 1 to the substrate 10 using the aforementioned adhesive 20, it is possible to fix the workpiece 1 to the substrate 10 in a short time, suppress a decrease in processing efficiency, and improve the processing accuracy during processing step 106, thereby suppressing cost increases.

[0088] It should be noted that the present invention is not limited to the embodiments described above. That is, it can be implemented with various modifications without departing from the core principles of the present invention. [Explanation of symbols]

[0089] 1 Workpiece (subject) 10 circuit boards 20 Adhesives 35 Ultraviolet light (light) 41 Holding Unit 46 Grinding Wheels 56. Infrared (Second Light) 81 Holding Unit 85 Cutting Blades 91 Holding Unit 96 Laser beams 101 Adhesive preparation steps 102 Application Step 103 Irradiation Step 104 Fixed step 105 Holding step 106 Machining Steps 107 Removal Steps

Claims

1. An adhesive for bonding adherends, Epoxy resin and Oxetane resin and An adhesive comprising a composition consisting of a reactive diluent and a polymerization initiator, the polymerization of which is initiated by irradiation with light.

2. The adhesive according to claim 1, further comprising a light-absorbing material that absorbs light of a different wavelength than the light that initiates polymerization.

3. A method for fixing a workpiece, Epoxy resin and Oxetane resin and An adhesive preparation step involves preparing an adhesive by adding a polymerization initiator, which initiates polymerization upon irradiation with light, to a composition comprising a reactive diluent and A coating step of applying the adhesive to at least one of the substrate and the workpiece, An irradiation step of irradiating the adhesive with the light, A fixing method comprising: performing the irradiation step, and then fixing the workpiece on the substrate by interposing the adhesive between the substrate and the workpiece.

4. The fixing method according to claim 3, wherein the substrate is made of a silicon wafer.

5. A method for processing a workpiece, Epoxy resin and Oxetane resin and An adhesive preparation step involves preparing an adhesive by adding a polymerization initiator, which is activated by light irradiation, to a composition comprising a reactive diluent and A coating step of applying the adhesive to at least one of the substrate and the workpiece, An irradiation step of irradiating the adhesive with the light, After performing the irradiation step, a fixing step is performed in which the adhesive is interposed between the substrate and the workpiece to fix the workpiece onto the substrate, A holding step in which the substrate side is held by a holding unit to expose the workpiece, A processing method comprising: a processing step of processing the workpiece, which is exposed and held on the substrate side by the holding unit.

6. The adhesive further comprises a light-absorbing material that absorbs a second light of a different wavelength than the said light, The processing method according to claim 5, further comprising a removal step of irradiating the adhesive with the second light after performing the processing step to remove the workpiece from the substrate.

7. The machining method according to claim 5 or claim 6, wherein the machining step involves grinding the workpiece with a grinding wheel.

8. The machining method according to claim 5 or claim 6, wherein the machining step involves cutting the workpiece with a cutting blade.

9. The processing method according to claim 5 or claim 6, wherein the processing step involves irradiating the workpiece with a laser beam.

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