Expansion method
The described expansion method uses a liquid resin and far-infrared heating to maintain chip spacing by applying and curing the resin on the sheet, addressing the issue of gap narrowing in existing methods.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- DISCO CORP
- Filing Date
- 2022-10-20
- Publication Date
- 2026-06-26
AI Technical Summary
Existing expansion methods fail to maintain the spacing between chips after expansion due to the elastic restoring force of the sheet, causing gaps to narrow over time.
An expansion method involving a liquid resin application, expansion, and heating process where a light-absorbing material is used to absorb far-infrared rays, applying a liquid resin to a sheet exposed on the workpiece, expanding it to form gaps, and then heating and shrinking the sheet with the resin to fix the spacing.
The method effectively prevents the narrowing of the spacing between chips post-expansion by fixing the expanded sheet with a cured resin, ensuring stable chip separation.
Smart Images
Figure 0007880793000001 
Figure 0007880793000002 
Figure 0007880793000003
Abstract
Description
Technical Field
[0001] The present invention relates to an expansion method for expanding a sheet of a workpiece unit.
Background Art
[0002] The workpiece is individualized by expanding a sheet adhered to a workpiece in which a modified layer or a groove is formed along a planned division line (see, for example, Patent Document 1). Further, a gap is formed between individual chips formed by dividing the workpiece by expanding the sheet in a state where the workpiece adhered to the sheet is divided.
[0003] In the expansion method disclosed in Patent Document 1 described above, when the sheet is expanded, the sheet between the outer periphery of the workpiece and the inner periphery of the frame loosens, and adjacent chips may come into contact with each other and be damaged. Therefore, the expansion device disclosed in Patent Document 1 described above includes a heating unit that heats and shrinks the loosened sheet.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, in the expansion method disclosed in Patent Document 1, even if a sufficient gap is formed between adjacent chips after heating, over time, the expansion of the sheet returns due to the elastic restoring force of the sheet, and the gap between adjacent chips narrows, and improvement is eagerly desired.
[0006] An object of the present invention is to provide an expansion method capable of suppressing narrowing of the interval between chips after expansion of the sheet.
Means for Solving the Problems
[0007] To solve the above-mentioned problems and achieve the objective, the present invention provides an expansion method for expanding a sheet of a workpiece unit in which a workpiece divided along a plurality of intersecting division lines or having division starting points formed is housed in an opening of a frame via a sheet, comprising: a liquid resin application step of applying a liquid resin to the sheet exposed on the outside of the workpiece of the workpiece unit; an expansion step of expanding the sheet of the workpiece unit after performing the liquid resin application step to form gaps between individual chips formed by the division of the workpiece along the division starting points; and a heating step of heating and shrinking the sheet between the outside of the workpiece and the inner circumference of the frame together with the liquid resin, while the workpiece is held via the sheet on a holding table having a holding surface for holding the workpiece, and the liquid resin is dried and cured.
[0008] In the expansion method described above, the liquid resin may include a light-absorbing material that absorbs far-infrared rays, and in the heating step, the sheet may be heated and shrunk by irradiating the liquid resin with far-infrared rays. [Effects of the Invention]
[0009] This invention has the effect of suppressing the narrowing of the spacing between chips after the sheet has been expanded. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1 is a perspective view showing an example of a workpiece unit to be processed by the expansion method according to Embodiment 1. [Figure 2] Figure 2 is a flowchart showing the flow of the extension method according to Embodiment 1. [Figure 3] Figure 3 is a schematic side view showing a partial cross-section of the liquid resin coating step of the expansion method shown in Figure 2. [Figure 4] Figure 4 is a schematic side view showing a modified example of the liquid resin coating step of the expansion method shown in Figure 2, partially in cross-section. [Figure 5] Figure 5 is a perspective view showing a segmented example of the configuration of an expansion device that performs the frame fixing step, expansion step, and heating step of the expansion method shown in Figure 2. [Figure 6] Figure 6 is a side view showing a partial cross-section of the expansion device shown in Figure 5. [Figure 7] Figure 7 is a schematic side view showing a partial cross-section of the state in which the frame of the workpiece unit is fixed during the expansion step of the expansion method shown in Figure 2. [Figure 8] Figure 8 is a schematic side view showing a partial cross-section of the expanded sheet of the workpiece unit after it has been expanded in the expansion step of the expansion method shown in Figure 2. [Figure 9] Figure 9 is a schematic side view showing a partial cross-section of the heating step of the expansion method shown in Figure 2. [Figure 10] Figure 10 is a perspective view showing a modified example of the workpiece unit shown in Figure 1. [Modes for carrying out the invention]
[0011] 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.
[0012] [Embodiment 1] The expansion method according to Embodiment 1 of the present invention will be described with reference to the drawings. Figure 1 is a perspective view showing an example of a workpiece unit to be processed by the expansion method according to Embodiment 1. Figure 2 is a flowchart showing the flow of the expansion method according to Embodiment 1.
[0013] (Workpiece unit) The expansion method according to Embodiment 1 is a device for expanding the expandable sheet 3 which is a sheet of the workpiece unit 1 shown in FIG. 1. As shown in FIG. 1, the workpiece unit 1 includes a workpiece 2, an expandable sheet 3, and a frame 4.
[0014] In Embodiment 1, the workpiece 2 is a wafer such as a disk-shaped semiconductor wafer or an optical device wafer having a substrate such as silicon, sapphire, gallium arsenide, or SiC (silicon carbide). As shown in FIG. 1, devices 7 are formed in respective regions of the surface 5 partitioned by a plurality of planned division lines 6 intersecting each other.
[0015] The device 7 is, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), a MEMS (Micro Electro Mechanical Systems), or various memories (semiconductor memory devices).
[0016] The workpiece 2 is irradiated with a laser beam having a wavelength that is transmissive to the substrate from the back surface 8 side on the back side of the surface 5 along the planned division line 6, and a modified layer 9 (shown by a dotted line in FIG. 1) which is a starting point of division is formed along the planned division line 6 inside the substrate. The workpiece 2 is divided into individual chips 10 starting from the modified layer 9. The chip 10 includes a part of the substrate divided along the planned division line 6 and a device 7 formed on the surface of the substrate.
[0017] Note that the modified layer 9 means a region in which the density, refractive index, mechanical strength, and other physical properties are different from those of the surroundings, and examples thereof include a melting treatment region, a crack region, an insulation breakdown region, a refractive index change region, and a region in which these regions are mixed.
[0018] The expanded sheet 3 is made of a stretchable resin and has heat-shrinkable properties, shrinking when heated. The expanded sheet 3 is formed in the shape of a disc with an outer diameter larger than the outer diameter of the workpiece 2 and comprises a base layer made of a synthetic resin that is stretchable and heat-shrinkable, and an adhesive layer laminated on the base layer and attached to the workpiece 2, and made of a synthetic resin that is stretchable and heat-shrinkable.
[0019] The surface of the adhesive layer is the adhesive surface 11 to which the back surface 8 of the workpiece 2 is attached. In Embodiment 1, the expanded sheet 3 comprises a base layer and an adhesive layer, but in the present invention, the sheet may consist only of a base layer made of a thermoplastic resin (polyolefin resin, polyethylene, polypropylene, or polystyrene, etc.) that is heat-pressed to the workpiece 2.
[0020] Frame 4 is formed in an annular shape with an inner diameter larger than the outer diameter of the workpiece 2, and the outer edge of the expanded sheet 3 is attached to it.
[0021] In the workpiece unit 1 with the configuration described above, the workpiece 2, which has a modified layer 9 forming along multiple intersecting division lines 6 that serve as the division starting point, is housed in the opening 12 of the frame 4 via an expanded sheet 3.
[0022] (Expansion method) The expansion method according to Embodiment 1 comprises a liquid resin coating step 201, an expansion step 202, and a heating step 203, as shown in Figure 2.
[0023] (Liquid resin coating step) Figure 3 is a schematic side view showing a partial cross-section of the liquid resin coating step of the expansion method shown in Figure 2. Figure 4 is a schematic side view showing a partial cross-section of a modified example of the liquid resin coating step of the expansion method shown in Figure 2. The liquid resin coating step 201 is a step in which the coating apparatus 20 shown in Figure 3 applies liquid resin 25 to the area 13 of the adhesive surface 11 of the expanded sheet 3 that is exposed on the outer circumference side of the workpiece 2 of the workpiece unit 1.
[0024] In Embodiment 1, during the liquid resin coating step 201, the coating device 20 holds the back surface 8 of the workpiece 2 to the holding surface 22 of the spinner table 21 via the expanded sheet 3, as shown in Figure 3, and clamps the frame 4 with the clamping portion 23 provided around the spinner table 21.
[0025] In the liquid resin coating step 201, as shown in Figure 3, the coating device 20 covers the entire surface 5 of the workpiece 2 with a sheet 26, rotates the spinner table 21 around its axis, and drops liquid resin 25 from the liquid resin supply nozzle 24 onto the center of the surface 5 of the workpiece 2. The dropped liquid resin 25 flows from the center to the outer edge on the sheet 26 on the surface 5 of the workpiece 2 due to the centrifugal force generated by the rotation of the spinner table 21, and is coated onto the entire surface of the sheet 26 on the surface 5 of the workpiece 2 and the area 13 of the adhesive surface 11 of the expanded sheet 3.
[0026] The liquid resin 25 includes, for example, a liquid water-soluble resin such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP). In Embodiment 1, the liquid resin 25 includes a light-absorbing material that absorbs far-infrared rays, but in the present invention, it does not need to include a light-absorbing material. For example, carbon black or phthalocyanine can be used as the light-absorbing material. In addition, as the liquid water-soluble resin constituting the liquid resin 25, for example, HogoMax (registered trademark, manufactured by DISCO Corporation) can be used.
[0027] In Embodiment 1, in the liquid resin coating step 201, after coating the liquid resin 25, the coating device 20 rotates the spinner table 21 around its axis for about 30 seconds to 1 minute without supplying liquid resin 25 from the liquid resin supply nozzle 24, thereby allowing the liquid resin 25 applied to the entire surface of the sheet 26 on the surface 5 of the workpiece 2 and the adhesive surface 11 of the expanded sheet 3 to be primary dried. Primary drying refers to the external drying of the liquid resin 25 by rotating the spinner table 21 around its axis for about 30 seconds to 1 minute without supplying liquid resin 25 from the liquid resin supply nozzle 24, resulting in a state where the liquid resin contains moisture internally and allows for expansion and contraction of the expanded sheet 3.
[0028] In Embodiment 1, in the liquid resin coating step 201, after coating and primary drying of the liquid resin 25, the primary dried liquid resin 25 on the surface 5 of the workpiece 2 is peeled off sheet by sheet 26 and applied to the area 13 of the adhesive surface 11 of the expanded sheet 3 without being applied to the surface 5 of the workpiece 2. In addition, in the present invention, in the liquid resin coating step 201, as shown in Figure 4, the coating device 20 may apply the liquid resin 25 from the liquid resin supply nozzle 24 only to the area 13 of the adhesive surface 11 of the expanded sheet 3 without covering the surface 5 of the workpiece 2 with the sheet 26.
[0029] (Expansion device) Next, the configuration of the expansion device 100 that performs the expansion step 202 and heating step 203 of the expansion method shown in Figure 2 will be described. Figure 5 is a perspective view showing a divided example of the configuration of the expansion device that performs the frame fixing step, expansion step and heating step of the expansion method shown in Figure 2. Figure 6 is a side view showing a partial cross-section of the expansion device shown in Figure 5.
[0030] The expansion device 100 shown in Figures 5 and 6 is a device that expands the expanded sheet 3 of the workpiece unit 1 and divides the workpiece 2 into individual chips 10 along the planned division line 6, starting from the modified layer 9 which serves as the dividing point. As shown in Figures 5 and 6, the expansion device 100 comprises a chamber 110, a frame fixing unit 120, an expansion unit 130, a holding table 140, a heating unit 150, and a control unit (not shown).
[0031] The chamber 110 is box-shaped and houses the frame fixing unit 120, the expansion unit 130, the holding table 140, and the heating unit 150. The chamber 110 is provided with an entrance / exit (not shown) that allows the workpiece unit 1 to be easily inserted and removed. In Embodiment 1, the entrance / exit is opened and closed by an opening / closing door.
[0032] The frame fixing unit 120 fixes the frame 4 of the workpiece unit 1 and comprises a frame mounting plate 121 and a frame retaining plate 122. The frame mounting plate 121 has a circular opening 123 in its planar shape and is formed as a plate with a flat upper surface 124 that is parallel to the horizontal direction. The inner diameter of the opening 123 of the frame mounting plate 121 is the same as the inner diameter of the frame 4. The frame mounting plate 121 is placed on the upper surface 124 with the workpiece 2 positioned on the opening 123.
[0033] In Embodiment 1, the frame mounting plate 121 moves up and down vertically by a cylinder 125 (shown in Figure 5). That is, the frame mounting plate 121 is attached to the end of a retractable rod 126 of the cylinder 125, and is provided to move up and down vertically as the rod 126 of the cylinder 125 extends and retracts.
[0034] The frame retaining plate 122 is fixed to the chamber 110 above the frame mounting plate 121. The frame retaining plate 122 is formed in a plate shape with approximately the same dimensions as the frame mounting plate 121, and has a circular opening 127 in the center that is the same dimensions as the opening 123. The opening 127 of the frame retaining plate 122 is positioned coaxially with the opening 123 of the frame mounting plate 121.
[0035] The frame fixing unit 120 receives the workpiece unit 1 via a transport unit (not shown) as the rod 126 retracts and the workpiece unit 1 is placed on the upper surface 124 of the frame mounting plate 121 located below it. After the frame 4 of the workpiece unit 1 is placed on the upper surface 124 of the frame mounting plate 121, the rod 126 of the cylinder 125 extends and the frame mounting plate 121 rises. The frame fixing unit 120 then clamps and fixes the frame 4 of the workpiece unit 1 between the frame retaining plate 122 and the raised frame mounting plate 121.
[0036] The expansion unit 130 expands the expanded sheet 3 of the workpiece unit 1, which includes a frame 4 fixed by the frame fixing unit 120, by pressing the region 13 between the inner circumference of the frame 4 and the outer circumference of the workpiece 2 from the base material layer side, which is the back side of the adhesive surface 11. The expansion unit 130 comprises an expansion drum 131 and a plurality of pressing rollers 132.
[0037] In Embodiment 1, the expansion drum 131 is formed in a flat cylindrical shape with a closed bottom, and its outer diameter is smaller than the inner diameter of the frame 4 which is placed on the upper surface 124 of the frame mounting plate 121, and its inner diameter is larger than the outer diameter of the workpiece 2 which is attached to the expanded sheet 3. The expansion drum 131 is arranged coaxially with the frame fixing unit 120 within the openings 123, 127 of the frame fixing unit 120.
[0038] The pressing roller 132 is cylindrical in shape and is supported at the upper end of the expansion drum 131 so as to be rotatable around its axis (hereinafter referred to as the rotation axis). The pressing roller 132 is arranged at equal intervals in the circumferential direction of the expansion drum 131. The rotation axis of the pressing roller 132 is arranged parallel to the tangent to the expansion drum 131 in a plan view.
[0039] The extension drum 131 is attached to the lifting unit 133 and moves up and down vertically by the lifting unit 133. In other words, the extension drum 131 is attached to the end of the retractable rod of the lifting unit 133 and is provided to move up and down vertically as the rod of the lifting unit 133 extends and retracts.
[0040] In Embodiment 1, the expansion drum 131 moves vertically up and down between a position where the upper end of the pressure roller 132 is lowered by the lifting unit 133 and is on the same plane as the upper surface 124 of the frame mounting plate 121 of the frame fixing unit 120, a position where the upper end of the pressure roller 132 is raised and is on the same plane as the upper surface 124 of the frame mounting plate 121 of the frame fixing unit 120, and a position where the upper end of the pressure roller 132 is above the upper surface 124 of the frame mounting plate 121 of the frame fixing unit 120 that fixes the frame 4.
[0041] When the lifting unit 133 raises the frame, the upper end of the pressing roller 132 is positioned above the upper surface 124 of the frame mounting plate 121 of the frame fixing unit 120 that fixes the frame 4. As a result, the pressing roller 132 presses against the area 13 between the inner circumference of the frame 4 of the expanded sheet 3 of the workpiece unit 1 fixed by the frame fixing unit 120 and the outer circumference of the workpiece 2.
[0042] The expansion unit 130 fixes the frame 4 of the workpiece unit 1 with the frame fixing unit 120, and raises the expansion drum 131 and holding table 140 from a position where the upper end of the pressing roller 132 is below the upper surface 124 of the frame mounting plate 121 of the frame fixing unit 120 that fixes the frame 4, to a position where it is above the upper surface 124 of the frame mounting plate 121 of the frame fixing unit 120, thereby pressing the region 13 between the inner circumference of the frame 4 of the expanded sheet 3 of the workpiece unit 1 and the outer circumference of the workpiece 2 with the pressing roller 132, and expanding the expanded sheet 3 in the planar direction. After expanding the expanded sheet 3, the expansion unit 130 lowers the expansion drum 131 and holding table 140, thereby creating slack in the region 13 between the inner circumference of the frame 4 of the expanded sheet 3 of the workpiece unit 1 and the outer circumference of the workpiece 2.
[0043] The holding table 140 is formed in a disc shape with an outer diameter smaller than the inner diameter of the expansion drum 131, and is positioned inside the expansion drum 131 and coaxially with the expansion drum 131. The holding table 140 is fixed to the expansion drum 131. The holding table 140 has a horizontally flat holding surface 141 that sucks and holds the workpiece 2 of the workpiece unit 1 via the expanded sheet 3. The holding table 140 is disc-shaped with an outer diameter smaller than the inner diameter of the frame 4 and the expansion drum 131, and the holding surface 141 is made of a porous material such as porous ceramic and is connected to a suction source such as an ejector via a suction passage.
[0044] The back surface 8 of the workpiece 2 is placed on the holding surface 141 of the holding table 140 via the expanded sheet 3 of the workpiece unit 1, which has been transported by a transport unit (not shown). The holding table 140 can hold the back surface 8 of the workpiece 2 by suction, as the holding surface 141 is sucked by a suction source. The holding table 140 moves vertically up and down together with the expansion unit 130 by the lifting unit 133.
[0045] The heating unit 150 heats and shrinks the slack in the region 13 between the frame 4 of the expanded sheet 3, which is formed when the expanded sheet 3 is expanded by the expansion unit 130, and the workpiece 2. The heating unit 150 comprises a disc-shaped rotating plate 151 that is movable in the vertical direction and rotates around an axis parallel to the vertical direction, and a plurality of heating units 152.
[0046] The rotating plate 151 has an outer diameter smaller than the inner diameters of the openings 123 and 127, and larger than the outer diameter of the workpiece 2. The rotating plate 151 is arranged coaxially with the frame fixing unit 120, the extension unit 130, and the holding table 140.
[0047] The heating units 152 are arranged at equal intervals in the circumferential direction above the region 13 of the expanded sheet 3 of the workpiece unit 1, which includes the frame 4 fixed by the frame fixing unit 120, and are positioned on a circle corresponding to the region 13 of the expanded sheet 3. The heating units 152 are positioned on the outer edge of the rotating plate 151 that faces vertically to the region 13 of the expanded sheet 3 of the workpiece unit 1 held by the holding table 140 and the frame fixing unit 120. In Embodiment 1, four heating units 152 are provided at equal intervals in the circumferential direction, but the present invention is not limited to four.
[0048] The heating unit 152 is of a type that heats the region 13 of the expanded sheet 3 by irradiating far-infrared rays downward, for example, an infrared ceramic heater that heats up and emits far-infrared rays when a voltage is applied. The heating unit 152 rotates on the aforementioned region 13 of the expanded sheet 3 by rotating the rotating plate 151 around an axis coaxial with the axis of the holding table 140.
[0049] The heating unit 150, with its rotating plate 151 and heating section 152 lowering to face vertically the region 13 of the expanded sheet 3 of the workpiece unit 1 held by the holding table 140 and the frame fixing unit 120, rotates around its axis and swirls over the aforementioned region 13 of the expanded sheet 3, thereby heating and contracting the slack in the outer region 13 of the expanded sheet 3 over the workpiece 2.
[0050] The control unit controls the aforementioned components of the expansion device 100 to cause the expansion device 100 to perform machining operations on the workpiece unit 1. The control unit is a computer having an arithmetic processing unit with a microprocessor such as a CPU (central processing unit), a storage device with memory such as ROM (read-only memory) or RAM (random access memory), and an input / output interface device. The arithmetic processing unit of the control unit performs calculations according to the computer program stored in the storage device and outputs control signals for controlling the expansion device 100 to the aforementioned components of the expansion device 100 via the input / output interface device.
[0051] The control unit is connected to a display unit (not shown) which consists of a liquid crystal display device that displays the status of machining operations and images, and an input unit (not shown) which is used by the operator to register machining conditions, etc. The input unit consists of at least one of the following: a touch panel provided on the display unit and an external input device such as a keyboard.
[0052] (Extension step) Figure 7 is a schematic side view showing a partial cross-section of the state in which the frame of the workpiece unit is fixed in the expansion step of the expansion method shown in Figure 2. Figure 8 is a schematic side view showing a partial cross-section of the state in which the expanded sheet of the workpiece unit is expanded in the expansion step of the expansion method shown in Figure 2. The expansion step 202 is a step in which, after performing the liquid resin coating step 201, the expanded sheet 3 of the workpiece unit 1 is expanded to form gaps between the individual chips 10 that are formed when the workpiece 2 is divided along the modified layer 9.
[0053] In Embodiment 1, during expansion step 202, the expansion device 100 lowers the expansion drum 131, the holding table 140, and the frame mounting plate 121, and the workpiece unit 1 is transported by a transport unit (not shown), and the frame 4 of the workpiece unit 1 is placed on the upper surface 124 of the frame mounting plate 121. In Embodiment 1, during expansion step 202, as shown in Figure 7, the expansion device 100 raises the frame mounting plate 121 to clamp the frame 4 between the frame retaining plate 122 and the frame mounting plate 121, thereby fixing the workpiece unit 1.
[0054] In expansion step 202, the expansion device 100 raises the expansion drum 131 and the holding table 140 until the upper end of the pressure roller 132 is positioned above the upper surface 124 of the frame mounting plate 121 of the frame fixing unit 120 that secures the frame 4, as shown in Figure 8. Then, the pressure roller 132 provided at the upper end of the expansion drum 131 comes into contact with the region 13 of the expanded sheet 3, and the pressure roller 132 presses the region 13 from below upward, causing the expanded sheet 3 to expand in the planar direction. In expansion step 202, as a result of the expansion of the expanded sheet 3, tensile forces act radially on the expanded sheet 3.
[0055] When tensile force is applied radially to the expanded sheet 3 attached to the back surface 8 of the workpiece 2, a modified layer 9 is formed along the planned division line 6 of the workpiece 2, and the primary dried liquid resin 25 allows the expanded sheet 3 to expand and contract. As a result, the expanded sheet 3 expands and is divided into individual chips 10 along the planned division line 6, with the modified layer 9 as the starting point. In addition, the space between the chips 10 of the workpiece 2 widens, and gaps are formed between the chips 10.
[0056] (Heating step) Figure 9 is a schematic side view showing a partial cross-section of the heating step of the expansion method shown in Figure 2. After performing the expansion step 202, the heating step 203 is a step in which, with the workpiece 2 held via the expanded sheet 3 by a holding table 140 having a holding surface 141 for holding the workpiece 2, the area 13 of the sheet 26 between the outside of the workpiece 2 and the inner circumference of the frame 4 is heated together with the liquid resin 25 to shrink it and the liquid resin 25 is dried and cured.
[0057] In Embodiment 1, during the heating step 203, the expansion device 100, after expanding the expand sheet 3, uses the expand sheet 3 to hold the back surface 8 of the workpiece 2 against the holding surface 141 of the holding table 140 by suction, thereby maintaining the spacing between the chips 10. Also during the heating step 203, the expansion device 100 lowers the expansion unit 130 and the holding table 140 so that the upper ends of the holding surface 141 and the pressure rollers 132 are on the same plane as the upper surface 124 of the frame mounting plate 121 of the frame fixing unit 120. As a result, the workpiece unit 1 is held by suction of the workpiece 2 against the holding surface 141 of the holding table 140 via the expand sheet 3, and because the expand sheet 3 has expanded, slack is formed in the area 13 of the expand sheet 3.
[0058] In Embodiment 1, during the heating step 203, the expansion device 100 lowers the heating unit 150 so that the heating section 152 faces the region 13 of the expanded sheet 3, as shown in Figure 9. In Embodiment 1, during the heating step 203, the expansion device 100 drives all the heating sections 152 of the heating unit 150, and rotates the heating section 152 above the region 13 a predetermined number of times while irradiating the liquid resin 25 on the region 13 with far-infrared rays from all the heating sections 152. In this way, during the heating step 203, the expansion device 100 heats and shrinks the slack in the region 13 of the expanded sheet 3 around its entire circumference via the liquid resin 25, and completely dries the primary cured liquid resin 25. Thus, in Embodiment 1, in the heating step 203, far-infrared rays are irradiated onto the liquid resin 25 to heat and shrink the slack in the region 13 of the expanded sheet 3 via the liquid resin 25, and the shrunk region 13 is fixed with the completely dried liquid resin 25. Complete drying refers to a state in which the liquid resin 25 has dried to the point where the amount of moisture it contains is less than that of the primary drying.
[0059] As described above, in the expansion method according to Embodiment 1, liquid resin 25 is applied in advance to the region 13 of the expandable sheet 3 in the liquid resin application step 201, the expandable sheet 3 is expanded in the expansion step 202, and then the region 13 of the expandable sheet is heated and the liquid resin 25 is cured in the heating step 203. Therefore, in the expansion method according to Embodiment 1, the region 13 of the expandable sheet 3 is not only heated and shrunk, but is also fixed by the dried liquid resin 25.
[0060] As a result, the expansion method according to Embodiment 1 has the effect of preventing the shrunk expandable sheet 3 from returning to its pre-shrunk state and preventing the spacing between the chips 10 after the expandable sheet 3 has been expanded from narrowing.
[0061] Furthermore, in the expansion method according to Embodiment 1, liquid resin 25 is applied in advance to the region 13 of the expandable sheet 3 in the liquid resin application step 201, and after the expandable sheet 3 is expanded in the expansion step 202, the slack in the region 13 of the expandable sheet 3 is heated in the heating step 203 via the liquid resin 25 applied on the region 13. As a result, the gas generated when the expandable sheet 3 is heated is sealed with the completely dried liquid resin 25, and it is possible to suppress the gas generated from the expandable sheet 3 from adhering to the device 7.
[0062] 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. In Embodiment 1, a modified layer 9 was formed as the dividing point, but the present invention is not limited to this, and a laser-processed groove or a cutting groove may be formed as the dividing point.
[0063] Furthermore, in Embodiment 1, the workpiece 2 of the workpiece unit 1 may be divided into individual chips 10 along the division line 6 by a division groove 14 formed on the division line 6 as shown in Figure 10.
[0064] Figure 10 is a perspective view showing a modified example of the workpiece unit shown in Figure 1. In Figure 10, the same reference numerals are used for the same parts as in Embodiment 1, and their descriptions are omitted. The dividing groove 14 penetrates the workpiece 2 and divides the workpiece 2 into individual chips 10, and is formed by cutting or laser ablation of the workpiece 2.
[0065] In other words, in the present invention, the expansion method may widen the spacing between the chips 10 of the workpiece unit 1 that have been divided along a plurality of intersecting division lines 6 in the expansion step 202 compared to before the expansion step 202. [Explanation of Symbols]
[0066] 1. Workpiece Unit 2 Workpiece 3. Expandable sheet (sheet) 4 frames Planned division lines (6 divisions) 9. Modified layer (starting point of splitting) 10 chips 12 Aperture 25 Liquid resin 140 Holding Tables 141 Holding surface 201 Liquid resin coating step 202 Extension Steps 203 Heating step
Claims
1. A method for expanding a sheet of a workpiece unit in which a workpiece is housed in an opening of a frame via a sheet, the workpiece being divided along multiple intersecting division lines or having division starting points formed thereon, A liquid resin coating step involves applying a liquid resin to the sheet exposed on the outside of the workpiece unit of the workpiece, After performing the liquid resin coating step, the process includes an expansion step in which the sheet of the workpiece unit is expanded to form gaps between the individual chips formed by dividing the workpiece along the dividing point, After performing the expansion step, the workpiece is held via the sheet on a holding table having a holding surface for holding the workpiece, and the sheet between the outside of the workpiece and the inner circumference of the frame is heated together with the liquid resin to shrink it and the liquid resin is dried to harden it in a heating step, An expansion method comprising:
2. The liquid resin contains a light-absorbing material that absorbs far-infrared rays. The expansion method according to claim 1, wherein the heating step involves irradiating the liquid resin with far-infrared rays to heat and shrink the sheet through the liquid resin.