Method for cutting workpiece and resin application device

Abstract

To provide a processing object cutting method and a resin coating device that remove particles remaining on the cut surface of a chip and shortens a working time.SOLUTION: An expanding tape 6 is attached to the back surface 4 of an object 1 to be processed. A workpiece 1 is irradiated with a laser beam L along a scheduled cutting line 5 to form a modified region 7, and the expanding tape 6 is expanded to divide the workpiece 1 into a plurality of chips 1a while a gap G is formed between the plurality of chips. The expanding tape 6 is irradiated with ultraviolet rays. The gap G is filled with a resin R from the side surface 2 of the object 1 to be processed. The resin R is cured. A chip 1a is removed from the expanding tape 6.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a method for cutting a workpiece and a resin application device. [Background technology]

[0002] Conventionally, there is known a method for cutting an object to be processed, which divides the object into a plurality of chips. As a technique of this type, Patent Document 1 describes a technique for removing electricity from a material forming the object to be processed (a material forming the object to be processed, or a material that formed the object to be processed) when a stress is applied via a sheet to the object to be processed in which a modified region serving as a starting point for cutting has been formed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-142206 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned method for cutting an object to be processed, if particles remain on the cut surface of the chip, there is a problem that the particles may peel off from the cut surface of the chip during a subsequent transport process, etc., and adhere to functional elements of the chip, etc. In addition, in the above-mentioned method for cutting an object to be processed, it is desirable to shorten the operation time (so-called tact time improvement).

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a method for cutting a workpiece and a resin application apparatus that can remove particles remaining on the cut surface of a chip and shorten the working time. [Means for solving the problem]

[0006] The method for cutting an object to be processed according to the present invention includes a first step of attaching an expandable sheet to the front or back surface of the object to be processed; a second step of irradiating the object to be processed along the planned cutting line after the first step with laser light to form a modified area and expanding the expandable sheet to divide at least a portion of the object to be processed into a plurality of chips and form gaps between the plurality of chips and reaching the side of the object to be processed; a third step of irradiating the expandable sheet with ultraviolet light after the first step; a fourth step of filling the gaps with resin from the outer edge including the side of the object to be processed after the second and third steps; a fifth step of hardening the resin after the fourth step; and a sixth step of removing the chips from the expandable sheet after the fifth step.

[0007] In this method for cutting a workpiece, the workpiece is divided into a plurality of chips, resin is filled between the plurality of chips, the filled resin is hardened, and the chips are removed. When removing the chips, particles remaining on the cut surface of the chips can be attached to the resin to remove the particles. It has also been found that irradiating the expandable sheet with ultraviolet light can improve the wettability of the expandable sheet. Therefore, by irradiating the expandable sheet with ultraviolet light before filling with resin, the time until filling with resin is completed can be shortened. Therefore, it is possible to remove particles remaining on the cut surface of the chip and shorten the working time.

[0008] In the fourth step of the method for cutting a workpiece according to the present invention, the gap is filled with resin while the workpiece is placed on the table, and the table may be tilted so that the position on the table where the resin is applied is higher than the workpiece. By tilting the table on which the workpiece is placed in this way, it is possible to further shorten the time until filling with resin is completed.

[0009] In the fifth step of the method for cutting an object according to the present invention, the resin filling the gaps in the object may be hardened by irradiating the resin with ultraviolet light from below while the object is placed on the table. In this case, it is possible to prevent air bubbles from being included in the hardened resin.

[0010] In the fourth step of the method for cutting an object according to the present invention, the gaps are filled with resin while the object is placed on the table, and the amount of resin filled may be an amount such that the liquid level of the resin is below the top surface of the object and above the modified region closest to the top surface. This makes it possible to remove particles remaining on the cut surfaces of the chips while preventing the resin from overflowing between the chips.

[0011] In the first step of the method for cutting an object according to the present invention, an expandable sheet, a protective sheet, or a protective tape may be attached to one of the front and back surfaces of the object that faces the device layer, thereby preventing deterioration of the characteristics of the device layer.

[0012] In the method for cutting an object to be processed according to the present invention, in the first step, an expandable sheet may be attached to one of the front and back surfaces of the object to be processed that is opposite to the device layer side, and in the fourth step, a protective sheet or protective tape may be attached to the other of the front and back surfaces of the object to be processed that is opposite to the device layer side before the resin is applied. This can prevent the characteristics of the device layer from deteriorating.

[0013] In the second step of the method for cutting an object to be processed according to the present invention, the expandable sheet may be expanded so that the gap is 10 μm to 300 μm. If the gap is too narrow, when the chip is taken out, the resin filled in the gap and hardened cannot be held on the expandable sheet side, and some of the resin adheres to the taken out chip. If the gap is too wide, not only does the amount of resin required increase, leading to an increase in costs, but the rate at which the resin is filled in the gap (the rate at which the resin permeates) also slows down. In this regard, when the gap is 10 μm to 300 μm, the amount of resin required can be reduced, and when the chip is taken out, the resin can be reliably held on the expandable sheet side, preventing some of the resin from adhering to the chip.

[0014] The resin application device of the present invention comprises a table on which an object to be processed having an expandable sheet attached to its front or back surface is placed, a resin application unit which applies resin onto the expandable sheet of the object to be processed placed on the table, and an ultraviolet irradiation unit which irradiates ultraviolet rays onto the object to be processed placed on the table, wherein the object to be processed placed on the table has an expandable sheet which has been expanded and at least a portion of which is divided into a plurality of chips, and gaps are formed between the plurality of chips and extend to the sides, the resin application unit fills the gaps with resin from the outer edge including the sides of the object to be processed, and the ultraviolet irradiation unit irradiates ultraviolet rays onto the expandable sheet attached to the object to be processed placed on the table before the resin is applied, and irradiates ultraviolet rays onto the resin filled in the gaps of the object to be processed placed on the table after the resin is applied.

[0015] According to this resin application device, resin can be filled between the chips of the workpiece and the resin can be hardened. Therefore, when the chip is removed, the particles remaining on the cut surface of the chip can be attached to the resin and removed. By irradiating the expandable sheet with ultraviolet light before the resin is applied, the wettability of the expandable sheet can be improved and the time until the resin filling is completed can be shortened. Therefore, the particles remaining on the cut surface of the chip can be removed and the work time can be shortened. In addition, the same table can be used to apply the resin and irradiate with ultraviolet light, that is, it is possible to irradiate with ultraviolet light without transporting the workpiece after the resin is applied. Therefore, it is possible to prevent the applied unhardened resin from overflowing due to vibrations caused by transportation. Furthermore, the time from the application of the resin to the hardening of the resin by irradiation with ultraviolet light can be shortened, and it is also possible to prevent the deterioration of the characteristics of the device layer due to the unhardened resin.

[0016] The resin application device according to the present invention may further include an expanding section that expands an expandable sheet attached to the front or back surface of the workpiece on which the modified region is formed along the cutting line, to divide at least a part of the workpiece into a plurality of chips and form gaps between the plurality of chips and reaching the side surface of the workpiece. In this case, the division into chips and the formation of gaps are possible by utilizing the expanding section. Effect of the Invention

[0017] According to the present invention, it is possible to provide a workpiece cutting method and a resin application device that can remove particles remaining on the cut surfaces of chips and reduce the operation time. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram of a laser processing device used to form a modified region. [Diagram 2] FIG. 2 is a plan view of an object to be processed in which a modified region is to be formed. [Diagram 3] 3 is a cross-sectional view of the object taken along line III-III in FIG. 2. FIG. [Figure 4] FIG. 4 is a plan view of the object after laser processing. [Diagram 5] 5 is a cross-sectional view of the object taken along line VV of FIG. 4. FIG. [Figure 6] 6 is a sectional view of the object taken along line VI-VI of FIG. [Figure 7] FIG. 7 is a block diagram showing a schematic configuration of the resin applying device. [Figure 8] FIG. 8 is a schematic diagram showing the table, the resin applying unit, and the ultraviolet ray applying unit. [Figure 9] Fig. 9(a) is a schematic cross-sectional view for explaining a method for cutting an object according to an embodiment. Fig. 9(b) is a schematic cross-sectional view showing a continuation of Fig. 9(a). Fig. 9(c) is a schematic cross-sectional view showing a continuation of Fig. 9(b). [Figure 10] Fig. 10(a) is a schematic cross-sectional view showing a continuation of Fig. 9(c), and Fig. 10(b) is a schematic cross-sectional view showing a continuation of Fig. 10(a). [Figure 11] Fig. 11(a) is a schematic cross-sectional view showing a continuation of Fig. 10(b), and Fig. 11(b) is a schematic cross-sectional view showing a continuation of Fig. 11(a). [Figure 12] Fig. 12(a) is a schematic cross-sectional view illustrating a case where ultraviolet light is irradiated onto a resin from above, and Fig. 12(b) is a schematic cross-sectional view illustrating air bubbles contained in a cured resin. [Figure 13] FIG. 13 is a schematic cross-sectional view illustrating the amount of resin applied. [Figure 14] Fig. 14(a) is a cross-sectional view showing an example in which an expandable tape is attached to the surface of the device layer side of the object to be processed, and Fig. 14(b) is a cross-sectional view showing an example in which a protective sheet is attached to the surface of the device layer side of the object to be processed. [Figure 15] FIG. 15 is a schematic cross-sectional view showing another example of the case where gaps in an object to be processed are filled with resin. [Figure 16]Fig. 16(a) is an enlarged plan view showing a part of the device layer side of the chip after the resin has been applied and filled into the gaps, but before the resin has hardened. Fig. 16(b) is an enlarged plan view showing the state of Fig. 16(a) after a predetermined time has elapsed. Fig. 16(c) is an enlarged plan view showing the state of Fig. 16(b) after a predetermined time has elapsed. Fig. 16(d) is an enlarged plan view showing the state of Fig. 16(c) after a predetermined time has elapsed. Fig. 16(e) is an enlarged plan view showing the state of Fig. 16(d) after a predetermined time has elapsed. Fig. 16(f) is an enlarged plan view showing the state of Fig. 16(e) after a predetermined time has elapsed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0020] In the object cutting method according to the embodiment, a modified region is formed in the object along a line to cut by focusing a laser beam on the object. First, the formation of the modified region will be described with reference to FIGS.

[0021] As shown in Fig. 1, the laser processing apparatus 100 is an apparatus used to implement the method for cutting an object to be processed. The laser processing apparatus 100 includes a laser light source 101, which is a laser light emitting unit that pulses and oscillates laser light L, a dichroic mirror 103 arranged to change the direction of the optical axis (optical path) of the laser light L by 90°, and a focusing lens 105 for focusing the laser light L. The laser processing apparatus 100 also includes a support table 107 for supporting the object to be processed 1 to be irradiated with the laser light L focused by the focusing lens 105, a stage 111 for moving the support table 107, a laser light source control unit 102 for controlling the laser light source 101 to adjust the output (pulse energy, light intensity), pulse width, pulse waveform, etc. of the laser light L, and a stage control unit 115 for controlling the movement of the stage 111.

[0022] In the laser processing apparatus 100, the laser light L emitted from the laser light source 101 has its optical axis direction changed by 90° by the dichroic mirror 103, and is focused by the focusing lens 105 inside the workpiece 1 placed on the support table 107. At the same time, the stage 111 is moved, and the workpiece 1 is moved relatively to the laser light L along the line 5 to cut. As a result, a modified region is formed in the workpiece 1 along the line 5 to cut. Note that, although the stage 111 is moved here to relatively move the laser light L, the focusing lens 105 may also be moved, or both may be moved.

[0023] As the object 1, a plate-like member (e.g., a substrate, a wafer, etc.) including a semiconductor substrate formed of a semiconductor material, a piezoelectric substrate formed of a piezoelectric material, etc. is used. As shown in FIG. 2, a cutting line 5 for cutting the object 1 is set on the object 1. The cutting line 5 is a virtual line extending in a straight line. When forming a modified region inside the object 1, as shown in FIG. 3, the laser light L is relatively moved along the cutting line 5 (i.e., in the direction of the arrow A in FIG. 2) with the focusing point (focusing position) P aligned inside the object 1. As a result, as shown in FIG. 4, FIG. 5, and FIG. 6, a modified region 7 is formed in the object 1 along the cutting line 5, and the modified region 7 formed along the cutting line 5 becomes a cutting start region 8.

[0024] The focal point P is a location where the laser light L is focused. The line 5 to cut may be a curved line or a straight line, may be a three-dimensional shape that is a combination of these, or may be a coordinate-specified line. The line 5 to cut may be a virtual line or a line that is actually drawn on the surface 3 of the object 1 to be processed. The modified region 7 may be formed continuously or intermittently. The modified region 7 may be in a row or in a dotted shape, and the modified region 7 may be formed at least inside the object 1 to be processed. In addition, a crack may be formed starting from the modified region 7, and the crack and the modified region 7 may be exposed to the outer surface (the surface 3, the back surface, or the outer peripheral surface) of the object 1 to be processed. The laser light incident surface when forming the modified region 7 is not limited to the surface 3 of the object 1 to be processed, and may be the back surface of the object 1 to be processed.

[0025] Incidentally, when a modified region 7 is formed inside the object 1, the laser light L passes through the object 1 and is absorbed particularly in the vicinity of the focal point P located inside the object 1. This forms a modified region 7 in the object 1 (i.e., internal absorption laser processing). In this case, the laser light L is hardly absorbed by the surface 3 of the object 1, so the surface 3 of the object 1 does not melt. On the other hand, when a modified region 7 is formed on the surface 3 or rear surface of the object 1, the laser light L is absorbed particularly in the vicinity of the focal point P located on the surface 3 or rear surface, and is melted and removed from the surface 3 or rear surface, forming a removed portion such as a hole or a groove (surface absorption laser processing).

[0026] The modified region 7 refers to a region in which the density, refractive index, mechanical strength, and other physical properties are different from those of the surroundings. The modified region 7 includes, for example, a melting process region (meaning at least one of a region that has been melted and then resolidified, a region in a molten state, and a region in a state of being resolidified from a melt), a crack region, a dielectric breakdown region, a refractive index change region, and the like, and also includes a mixture of these regions. Furthermore, the modified region 7 includes a region in which the density of the modified region 7 has changed compared to the density of a non-modified region in the material of the processing object 1, and a region in which lattice defects have been formed. When the material of the processing object 1 is single crystal silicon, the modified region 7 can also be called a high dislocation density region.

[0027] The melting process region, the refractive index change region, the region where the density of the modified region 7 has changed compared to the density of the non-modified region, and the region where lattice defects have been formed may further contain cracks (cracks, microcracks) inside these regions or at the interface between the modified region 7 and the non-modified region. The contained cracks may be formed over the entire surface of the modified region 7, or only in a part or a plurality of parts. The processing object 1 includes a substrate made of a crystalline material having a crystalline structure. For example, the processing object 1 includes a substrate made of at least one of gallium nitride (GaN), silicon (Si), silicon carbide (SiC), LiTaO3, and sapphire (Al2O3). In other words, the processing object 1 includes, for example, a gallium nitride substrate, a silicon substrate, a SiC substrate, a LiTaO3 substrate, or a sapphire substrate. The crystalline material may be either anisotropic crystal or isotropic crystal. The object 1 may include a substrate made of a non-crystalline material having a non-crystalline structure, for example, a substrate made of glass. The object 1 may include a quartz substrate made of quartz, for example.

[0028] In the embodiment, the modified region 7 can be formed by forming a plurality of modified spots (processing marks) along the line to cut 5. In this case, a plurality of modified spots are gathered to form the modified region 7. The modified spot is a modified portion formed by one pulse shot of pulsed laser light (i.e., one pulse of laser irradiation: laser shot). Examples of the modified spot include a crack spot, a melting processing spot, a refractive index change spot, or a mixture of at least one of these. The size of the modified spot and the length of the crack generated can be appropriately controlled in consideration of the required cutting accuracy, the required flatness of the cut surface, the thickness, type, crystal orientation, etc. of the object 1 to be processed. In addition, in the embodiment, the modified spot can be formed as the modified region 7 along the line to cut 5.

[0029] Next, a resin application device used in carrying out the workpiece cutting method will be described.

[0030] 7, the resin application device 10 includes an expanding section 12, a table 14, a resin application section 16, an ultraviolet irradiation section 18, and a control section 20. The expanding section 12 expands an expanding tape (expandable sheet) 6 attached to the front surface 3 or rear surface of the object 1 on which the modified region 7 has been formed along the line to cut 5 by the above-mentioned laser processing device 100, thereby dividing at least a part of the object 1 into a plurality of chips 1a and forming gaps that exist between the plurality of chips 1a and reach the side surface of the object 1. The expanding section 12 is not particularly limited, and various expanding mechanisms can be used.

[0031] 7 and 8, the table 14 places the workpiece 1 after the expanding tape 6 has been expanded by the expanding unit 12. The resin application unit 16 applies resin R onto the expanding tape 6 attached to the workpiece 1 placed on the table 14. The resin application unit 16 is, for example, a dispenser. The resin application unit 16 fills the resin R from the outer edge of the workpiece 1, including the side surface 2, into the gap G (described in detail later).

[0032] The ultraviolet irradiating unit 18 irradiates ultraviolet rays onto the workpiece 1 placed on the table 14. The ultraviolet irradiating unit 18 irradiates ultraviolet rays onto the expandable tape 6 attached to the workpiece 1 placed on the table 14 before the resin R is applied, and irradiates ultraviolet rays onto the resin R filled in the gaps of the workpiece 1 placed on the table 14 after the resin R is applied (details will be described later). The table 14, the resin application unit 16, and the ultraviolet irradiating unit 18 are disposed in a chamber 22. The inside of the chamber 22 is sealed and purged with, for example, nitrogen.

[0033] The control unit 20 is a computer configured with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The various operations in the control unit 20 are controlled, for example, by a program stored in the ROM being loaded onto the RAM and executed by the CPU. The control unit 20 may be configured as hardware such as an electronic circuit. The control unit 20 controls various operations of the resin application device 10. The control unit 20 controls the application of the resin R by the resin application unit 16. The control unit 20 controls the irradiation of ultraviolet rays by the ultraviolet irradiation unit 18.

[0034] Next, a method for cutting the workpiece will be described.

[0035] The workpiece cutting method is used as a chip manufacturing method for manufacturing a plurality of chips by laser processing the workpiece 1. The workpiece cutting method can be performed using the above-mentioned laser processing apparatus 100 and resin application apparatus 10. The workpiece 1 is, for example, in the shape of a disk having a thickness of 400 μm and a diameter of 8 inches. The workpiece 1 is, for example, a sapphire substrate, a SiC substrate, a glass substrate (strengthened glass substrate), a quartz substrate, a silicon substrate, a semiconductor substrate, a transparent insulating substrate, or the like. The workpiece 1 here is a single crystal silicon substrate.

[0036] A device layer is formed on the surface 3 side of the object 1, which is the laser light incident surface side. The device layer includes a plurality of functional elements (for example, light receiving elements such as photodiodes, light emitting elements such as laser diodes, or circuit elements formed as a circuit, etc.) arranged in a matrix. A plurality of lines to cut 5 (see FIG. 1) extending between adjacent functional elements are set on the surface 3 of the object 1. The plurality of lines to cut 5 extend in a lattice pattern. The device layer referred to here is a layer including at least one of a functional element, a structure, a laminate, a film structure, a resin layer (DAF, etc.), etc. The device layer is not particularly limited. In addition, there are at least two types of damage to the device layer referred to here: a "mode of penetrating between layers" and a "mode of adhering to the surface". The "mode of penetrating between layers" is a mode in which the resin R penetrates between the device layer and a base material such as silicon or glass on which the device layer is laminated in the object 1. The "interlayer penetration mode" is thought to occur when the adhesion between the device layer and the substrate is weak, or when one of the layers in the multilayer structure is easily affected by resin R (solubility, affinity, etc.). The "surface adhesion mode" is a mode in which resin R climbs up onto the surface of the device layer. The "surface adhesion mode" is thought to occur when the surface is in a state that has high affinity with resin R, etc.

[0037] First, in the object cutting method, as shown in Fig. 9(a), an expandable tape 6 is attached to the back surface 4 of an object 1 (first step). The expandable tape 6 is held, for example, by a circular frame. The expandable tape 6 is a tape material on the ultraviolet curing side. The expandable tape 6 includes a central region where the object 1 is placed and an outer edge region where the object 1 is not placed.

[0038] Next, the laser processing device 100 irradiates the object 1 with laser light L along the line to cut 5. As a result, as shown in FIG. 9(b), a modified region 7 is formed at least inside the object 1 along the line to cut 5 (second step). The processing conditions for forming the modified region 7 are not particularly limited as long as the processing conditions allow the object 1 to be divided into a plurality of chips 1a by expanding the expandable tape 6 in the subsequent step. For example, a crack may be exposed on at least one of the front surface 3 and the back surface 4 of the object 1, or may not be exposed.

[0039] Next, the expanding tape 6 is expanded by the expanding section 12. As a result, as shown in Fig. 9(c), for example, a crack extending from the modified region 7 is extended, and the object 1 is divided into a plurality of chips 1a. At the same time, the intervals between the chips 1a are expanded, and gaps G that exist between the plurality of chips 1a and reach the side surfaces 2 that are perpendicular (intersect) with the front surface 3 and rear surface 4 of the object 1 are formed (second step).

[0040] The gap G has a distance that allows the resin to penetrate in the subsequent resin filling step. The gap G is not particularly limited, but may be, for example, 10 μm to 300 μm, and is 50 μm here. The division into a plurality of chips 1a may be completed at the time when the modified region 7 is formed, and in this case, the expansion tape 6 is expanded for the purpose of ensuring the intervals between the chips 1a. A grip ring, a heat shrink, or the like can be used to hold the object 1 after the expansion tape 6 is expanded. After the expansion tape 6 is expanded, at least a part of the gap G formed between the plurality of chips 1a reaches the side surface 2 of the object 1.

[0041] Next, the workpiece 1 after expanding the expanding tape 6 is placed on a table 14 (see FIG. 8). As shown in FIG. 10(a), the expanding tape 6 of the workpiece 1 is irradiated with ultraviolet light from below (the back surface 4 side) by the ultraviolet light irradiation unit 18 (third step). The ultraviolet light irradiation may be performed multiple times or may be performed in one go. This hardens the expanding tape 6 and improves the wettability (wet tension) of the expanding tape 6. The adhesive force of the expanding tape 6 is reduced.

[0042] As shown in FIG. 10(b), the resin applicator 16 applies the resin R to the periphery of the object 1 at a predetermined distance from the side surface 2. This fills the gap G from the side surface 2 of the object 1 with the resin R (fourth step). Here, the resin applicator 16 applies the resin R to one or more locations on the outer edge region of the expanding tape 6 around the object 1. Alternatively, while applying the resin R to a position away from the side surface 2 of the object 1, the resin applicator 16 moves along the periphery of the object 1 one revolution, multiple revolutions, or less than one revolution. Instead of or in addition to the movement of the resin applicator 16, the table 14 on which the object 1 is placed may be rotated.

[0043] When filling the resin, the resin R is not directly filled in the gap G, but the resin R dropped around the workpiece 1 on the expandable tape 6 advances (penetrates) into the gap G by utilizing at least one of the capillary phenomenon, the selective wettability of the material side surface, and surface tension. When filling the resin, the resin R does not overflow onto the surface 3 of the workpiece 1, and does not return through the gap G.

[0044] The resin R is a liquid resin. The resin R is an ultraviolet curing resin. A resin having a shrinkage rate higher than a predetermined rate when cured is selected as the resin R so that the resin R can be easily peeled off from the chip 1a in a later stage. The resin R may be a gel-like, semi-solid, jelly-like, mousse-like or paste-like resin. The position where the resin R is applied may be, for example, 0.5 mm away from the side surface 2.

[0045] Next, with the workpiece 1 placed on the table 14, the ultraviolet irradiating unit 18 irradiates the resin R filling the gaps G of the workpiece 1 with ultraviolet light from below, as shown in Fig. 11(a). This causes the resin R to harden and shrink (fifth step). The irradiation of ultraviolet light may be performed multiple times, or may be performed in one go.

[0046] As shown in FIG. 11(b), the chip 1a is picked up and removed from the expanding tape 6 (sixth step). When the chip 1a is picked up, the hardened resin R is peeled off from the side of the chip 1a and adheres to the expanding tape 6 instead of the chip 1a, and is left on the expanding tape 6. Note that the chip 1a and the resin R may be peeled off by shrinkage of the resin R when it hardens due to irradiation with ultraviolet light, instead of or in addition to being peeled off by the force of the pick-up, or may be peeled off by re-expanding the expanding tape 6 after the resin R hardens.

[0047] As described above, in the method for cutting a workpiece according to the present embodiment, the workpiece 1 is divided into a plurality of chips 1a, the resin R is filled between the plurality of chips 1a, the filled resin R is hardened, and the chips 1a are taken out. When the chips 1a are taken out, the particles remaining on the cut surface of the chips 1a can be attached to the resin R and removed. In addition, by irradiating the expandable tape 6 with ultraviolet light before filling with the resin R, the wettability of the expandable tape 6 can be improved, the filling speed (permeation speed) of the resin R can be increased, and the time until filling between the plurality of chips 1a with the resin R can be shortened (tact time can be increased). Therefore, the particles remaining on the cut surface of the chips 1a can be removed and the working time can be shortened. In the present embodiment, for example, the time until filling with the resin R is completed can be shortened to about 1 / 8 compared to the case where the expandable tape 6 is not irradiated with ultraviolet light before filling with the resin R.

[0048] In the object cutting method of the present embodiment, while the object 1 is placed on a table 14, the resin R filled in the gaps G of the object 1 is irradiated with ultraviolet light from below (the expanding tape 6 side) to harden the resin R. For example, when ultraviolet light is irradiated onto the resin R from above as shown in FIG. 12(a), air bubbles 19 as shown in FIG. 12(b) may be contained inside the hardened resin R. In the present embodiment, by irradiating the resin R with ultraviolet light from below, the effect of shrinkage of the resin R can be released to the upper side, which is the open side, and such air bubbles 19 can be suppressed.

[0049] In the method for cutting an object to be processed according to the present embodiment, the control unit 20 may control the resin application unit 16 to fill the amount of resin R such that the liquid level R1 of the resin R is located below the surface (upper surface) 3 of the object to be processed 1 and above the modified region 7 closest to the surface 3 (see FIG. 13). This makes it possible to remove particles remaining on the cut surface of the chip 1a while preventing the resin R from overflowing between the chips 1a. In this case, the resin R does not come into contact with the device layer 9, so that deterioration of the characteristics of the device layer 9 can be prevented (the characteristics can be maintained). For example, the resin R may reach at least 350 μm of the plate thickness of, for example, 400 μm in the thickness direction of the object to be processed 1.

[0050] Note that the control unit 20 determines that the amount of resin R that can permeate the gap G per unit time by capillary action is fixed, so if the flow rate (the amount of resin R applied per unit time) is too large, the resin R may overflow from the surface 3 even if the filling amount (the total amount of resin R applied) is appropriate. Therefore, the control unit 20 may be capable of controlling the flow rate when applying the resin R. In this case, the control unit 20 can appropriately control the application flow rate of the resin R based on the amount of resin that can permeate the gap G per unit time by capillary action. It becomes possible to prevent the resin R from overflowing from the surface 3.

[0051] In the cutting method of the object to be processed according to the present embodiment, the expanding tape 6 may be expanded so that the gap G is 10 μm to 300 μm. As a result, if the gap G is too narrow, for example narrower than 10 μm, when the chip 1a is taken out, the resin R filled and hardened in the gap G cannot be held on the expanding tape 6 side, and a part of the resin R adheres to the taken out chip 1a. On the other hand, if the gap G is too wide, for example wider than 300 μm, the amount of resin required increases, leading to an increase in cost, and the permeation speed of the resin R into the gap G (the speed at which the resin R permeates) also slows. In this regard, when the gap G is 10 μm to 300 μm, the amount of resin required can be suppressed, while the resin R can be reliably held on the expanding tape 6 side when the chip 1a is taken out, and the adhesion of a part of the resin R to the chip 1a can be suppressed. Incidentally, in the present embodiment, for example, the thickness of the chip 1a is 400 μm, whereas the gap G is about 100 μm, realizing an aspect ratio of 4 to 1 or more.

[0052] According to the resin application device 10 of the present embodiment, the resin R can be filled between the chips 1a of the workpiece 1 and the resin R can be hardened. Therefore, when the chips 1a are taken out, the particles remaining on the cut surface of the chips 1a can be attached to the resin R and removed. By irradiating the expandable tape 6 with ultraviolet light before the application of the resin R, the wettability of the expandable tape 6 can be improved and the time required to complete the filling of the resin R between the chips 1a can be shortened. Therefore, the particles remaining on the cut surface of the chips 1a can be removed and the working time can be shortened. In addition, the application of the resin R and the irradiation of ultraviolet light can be performed using the same table 14, that is, the workpiece 1 can be irradiated with ultraviolet light without transporting the workpiece 1 after the application of the resin R. Therefore, it is possible to prevent the applied unhardened resin R from overflowing due to vibrations caused by transportation. Furthermore, the time from the application of the resin R to the hardening of the resin R by irradiation of ultraviolet light can be shortened, and it is also possible to prevent the deterioration of the characteristics of the device layer 9 due to the unhardened resin R.

[0053] 16(a) to 16(f) are plan views showing an enlarged portion of the device layer 9 side of the chip 1a after the resin R is applied and filled into the gap G and before the resin R is cured. The states shown in each of FIGS. 16(a) to 16(f) are shown in the order of time since the application of the resin R. As shown in FIGS. 16(a) to 16(f), when a certain time has elapsed since the application of the resin R, damage DM occurs in the device layer 9 due to the uncured resin R (see FIG. 16(e)). Then, it can be seen that the damage DM progresses (in the figure, it spreads so as to extend inward) (see FIG. 16(f)). From these results, it can be confirmed that if the time from the application of the resin R to the curing of the resin R by irradiation with ultraviolet light can be shortened, damage to the device layer 9 due to the uncured resin R and thus deterioration of characteristics can be suppressed.

[0054] The resin coating device 10 of this embodiment further includes an expanding section 12. In this case, the expanding section 12 can be used to divide the chips 1a and form the gaps G. In the resin coating device 10, the expanding section 12 may also serve as the table 14, or another table separate from the table 14 may be provided.

[0055] In this embodiment, if the expandable tape 6 is weakly adhered to the table 14 due to static electricity or the like, vibrations will occur, for example, when removing the chip 1a. Therefore, such vibrations can be suppressed, for example, by providing an embossed portion on the mounting surface of the table 14 or by providing an anti-static portion using an ionizer or the like.

[0056] The above describes a preferred embodiment of the present invention, but the present invention is not limited to the above embodiment, and may be modified or applied to other things without departing from the gist of the claims.

[0057] 14(a), an expandable tape 6 may be attached to the surface 3 of the object 1 on the device layer 9 side. This can prevent the characteristics of the device layer 9 from deteriorating.

[0058] 14(b), in the step of attaching the expandable tape 6 to the back surface 4 of the object 1 opposite to the device layer 9 side and filling with resin R, a protective sheet HG may be attached to the front surface 3 of the object 1 on the device layer 9 side before applying the resin R. This can prevent the characteristics of the device layer 9 from deteriorating.

[0059] In the above embodiment, in the first step, a protective sheet HG may be attached to the surface 3 of the object 1 on the device layer 9 side. In this case, the expandable tape 6 is attached to the back surface 4 of the object 1. The protective sheet HG may be reattached after expanding the expandable tape 6 in the second step. Even in such a case, deterioration of the characteristics of the device layer 9 can be prevented.

[0060] Incidentally, the protective sheet HG is not particularly limited, and various sheets such as a sheet that does not expand can be used. Instead of the protective sheet HG, for example, a protective tape that does not expand, such as a back grind tape, can be used. The protective tape is not particularly limited, and various tapes can be used.

[0061] As shown in FIG. 15, in the method for cutting a workpiece, resin is filled into the gap G with the workpiece 1 placed on the table 14, and the table 14 may be tilted so that the position on the table 14 where the resin R is applied is higher than the workpiece 1. By tilting the table 14 on which the workpiece 1 is placed in this manner, it is possible to further shorten the time until the resin R is filled between the multiple chips 1a. The tilt of the table 14 is particularly effective when the resin R is applied from one side in the direction along the surface 3 of the workpiece 1, rather than the entire periphery of the workpiece 1. The table 14 here has a configuration for tilting the table 14. The configuration for tilting the table 14 is not particularly limited, and a known configuration can be used.

[0062] In filling the resin R in the above embodiment, instead of or in addition to applying the resin R to the periphery at a predetermined distance from the side surface 2 of the workpiece 1, the resin R may be applied to at least a part of the outer edge portion including the side surface 2 of the workpiece 1, and the resin R may be filled from this outer edge portion into the gap G. The outer edge portion may be a bevel region on the outer periphery of the workpiece 1. Even in this case, filling the resin R into the gap G can be effectively achieved.

[0063] In the above embodiment, the expanding tape 6 may be irradiated with ultraviolet rays at any timing before application of the resin R. In the above embodiment, after the expanding tape 6 is irradiated with ultraviolet rays, the applied resin R may be filled into the gap G from the side surface 2 of the object 1 while the gap G is being formed (growing) by the expansion of the expanding tape 6.

[0064] In the above embodiment, the resin application unit 16 is not limited to a dispenser, and various application means may be used. The resin application unit 16 may be, for example, a mechanism for applying the resin R by an inkjet method, or a mechanism for applying the resin R by screen printing. When a mechanism for applying the resin R by screen printing is used for the resin application unit 16, it is possible to apply the resin R in a circumferential shape along the outer edge of the workpiece 1 in a short time.

[0065] In the above embodiment, an ultraviolet curing resin that utilizes ultraviolet curing is used as the resin R, but there is no particular limitation to the resin R. For example, the resin R may be a resin that utilizes a curing reaction that uses external energy such as heat curing, or a resin that utilizes room temperature reaction curing.

[0066] In the above embodiment, before the chip 1a is taken out, at least a part of the hardened resin R may be removed. In this case, it is possible to remove particles remaining on the cut surface of the chip 1a together with the resin R before the chip 1a is taken out.

[0067] In the above embodiment, the expandable tape 6 is used as an expandable sheet to divide the workpiece 1 into chips 1a, but it is not limited to the expandable tape 6, and various expandable sheet materials or tape materials may be used. For example, a knife edge, a breaker device, a roller device, or the like may be further used during expansion. In the above, "hardening" also includes a mode in which the resin does not completely solidify. Hardening only needs to solidify at least a part of the liquid resin R, and the resin R shrinks due to hardening. The hardened resin R may contain at least one of gaseous (vapor) resin R and liquid resin R.

[0068] In the above embodiment, the resin application unit 16 may apply the resin R to the workpiece 1 placed on a table other than the table 14 on which the workpiece 1 is placed when irradiated with ultraviolet rays by the ultraviolet irradiation unit 18. In other words, the workpiece 1 may be configured to be placed on different tables when applying the resin R and when irradiating with ultraviolet rays. In this case, the workpiece 1 after being coated with the resin R may be transported to the table of the ultraviolet irradiation unit 18 by, for example, transporting it horizontally so as not to generate vibrations. [Explanation of symbols]

[0069] 1...object to be processed, 1a...chip, 2...side, 3...surface (top), 4...back, 5...planned cutting line, 6...expanding tape (expandable sheet), 7...modified area, 9...device layer, 10...resin application device, 12...expanding section, 14...table, 16...resin application section, 18...ultraviolet light irradiation section, G...gap, HG...protective sheet, L...laser light, R...resin.

Claims

1. A first step of attaching an expandable sheet that hardens when irradiated with ultraviolet light to the front or back surface of an object to be processed; After the first step, a second step is performed in which a laser beam is irradiated onto the object along a line to be cut to form a modified region, and the expandable sheet is expanded to divide at least a portion of the object into a plurality of chips, and gaps are formed between the plurality of chips and extending to the side of the object; A third step of irradiating the expandable sheet with ultraviolet light after the first step to harden the expandable sheet; a fourth step of filling the gap with resin from an outer edge portion including the side surface of the object to be processed after the second step and the third step; a fifth step of curing the resin after the fourth step; A sixth step of removing the chip from the expandable sheet after the fifth step, In the third step, the expandable sheet is irradiated with ultraviolet light to improve the wettability of the expandable sheet and reduce the adhesive force of the expandable sheet to the object to be processed; In the first step, the expandable sheet is attached to one of the front surface and the back surface of the object to be processed, the one opposite to the device layer side; In the fourth step, before the application of the resin, a protective sheet or protective tape is attached to the other of the front surface and the back surface of the object, which is closer to the device layer.

2. In the fourth step, The resin is filled into the gap while the workpiece is placed on a table, 2. The method for cutting a workpiece according to claim 1, further comprising the step of tilting the table so that a position on the table where the resin is applied is higher than the workpiece.

3. In the fifth step, the resin filled in the gap of the object to be processed is irradiated with ultraviolet light from below while the object is placed on a table, thereby hardening the resin; The method for cutting an object to be processed according to claim 1 or 2, wherein in the third step, while the object to be processed is placed on a table, ultraviolet light is irradiated onto the expandable sheet from the front or back side of the object to which the expandable sheet is attached, thereby improving the wettability of the expandable sheet and reducing the adhesive force of the expandable sheet to the object to be processed.

4. In the fourth step, The resin is filled into the gap while the workpiece is placed on a table, A method for cutting a workpiece according to any one of claims 1 to 3, wherein the filling amount of resin is an amount such that the liquid level of the resin is below the top surface of the workpiece and above the modified area closest to the top surface.

5. The method for cutting an object to be processed according to any one of claims 1 to 4, wherein in the first step, the expandable sheet, protective sheet or protective tape is attached to one of the front surface and the back surface of the object to be processed, the one facing the device layer.

6. The method for cutting an object to be processed according to any one of claims 1 to 5, wherein in the second step, the expandable sheet is expanded so that the gap is 10 μm to 300 μm.

7. A table on which an object to be processed is placed, the object having an expandable sheet that is hardened by irradiation with ultraviolet light attached to one of the front surface or the back surface opposite to the device layer side, and a protective sheet or protective tape attached to the other of the front surface or the back surface on the device layer side; A resin applicator that applies resin onto the expandable sheet of the object to be processed placed on the table; an ultraviolet irradiating unit that irradiates the object placed on the table with ultraviolet rays, The workpiece placed on the table has the expandable sheet expanded, at least a portion of the workpiece is divided into a plurality of chips, and gaps are formed between the plurality of chips and reach the sides of the chips; The resin application unit fills the gap with resin from an outer edge portion including the side surface of the object to be processed, The ultraviolet ray irradiation unit includes: Before applying the resin, the expandable sheet attached to the workpiece placed on the table is irradiated with ultraviolet light to harden the expandable sheet, improve the wettability of the expandable sheet, and reduce the adhesive force of the expandable sheet to the workpiece; a resin application device that irradiates ultraviolet light onto the resin that has filled the gaps of the workpiece placed on the table after the resin has been applied, thereby hardening the resin.

8. The resin application device described in claim 7, further comprising an expanding section that expands the expandable sheet attached to the front or back surface of the workpiece on which a modified region is formed along a planned cutting line, thereby dividing at least a portion of the workpiece into a plurality of chips and forming gaps between the plurality of chips and reaching the side of the workpiece.

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