Chip spacing method

Abstract

To form a predetermined gap between chips well.SOLUTION: In a chip spacing forming step, friction between an expanded sheet 113 and a holding surface 622 of a holding table 62 installed below the expanded sheet 113 is reduced by blowing air from the holding surface 622. Therefore, the expanded sheet 113 can be easily expanded, such that the predetermined gap between the chips 120 can be well formed.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a chip spacing forming method for forming a predetermined spacing between a plurality of chips constituting a workpiece by expanding an expand sheet. [Background technology]

[0002] There is a process in which a wafer, which has fracture origins formed inside along the intended division line, or a wafer which has been divided into multiple chips along the intended division line, is attached to an expandable sheet and the space between the chips is increased by expanding the expandable sheet.

[0003] There is also a process in which the above-mentioned wafer is attached to an expandable sheet laminated with an adhesive sheet called a die attach film, and the expandable sheet is expanded to increase the spacing between chips on the wafer and divide the die attach film according to the chips.

[0004] The sheet expanding device has a frame fixing portion, a suction holding table, and an expansion drum arranged on the outer periphery of the suction holding table. The expanding drum is vertically raised to expand the expanding sheet and expand the tip interval. After that, the expanding sheet is suction-held by the suction holding table to maintain the expanded tip interval. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6741529 [Patent Document 2] JP 2007-123658 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above-mentioned sheet expanding device, when the expanding drum is raised, the expanding drum and the suction holding table are arranged on almost the same plane, so that friction occurs between the central area of ​​the expanding sheet corresponding to the chips and the holding surface of the suction holding table, making it difficult to sufficiently expand the central area of ​​the expanding sheet.

[0007] An object of the present invention is to provide a method for effectively forming a predetermined gap between chips. [Means for solving the problem]

[0008] The chip spacing forming method of the present invention is a chip spacing forming method for forming a predetermined gap between a plurality of chips constituting a workpiece supported via an expandable sheet in an opening of an annular frame, the method comprising the steps of: The expand sheet; A holding surface of a holding table installed below the expandable sheet When the holding surface comes into contact with the the step of expanding the expanded sheet to form a predetermined gap between the chips while reducing friction between the expanded sheet and the holding surface by blowing air from the expanded sheet; and the step of shrinking, after the chip spacing forming step, sucking and holding the area of ​​the expanded sheet corresponding to the chips by the holding surface of the holding table, and shrinking the portion of the expanded sheet between the inner peripheral edge of the annular frame and the outer peripheral edge of the workpiece by heating the portion while maintaining the gap between the chips. Effect of the Invention

[0009] In the chip spacing forming method of the present invention, in the chip spacing forming step, air is ejected from the holding surface of the holding table installed below the expandable sheet to reduce friction between the expandable sheet and the holding surface. Therefore, it is possible to easily expand the area of ​​the expandable sheet corresponding to the chips, and it is possible to satisfactorily form a predetermined gap between the chips. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view of a work set including a wafer. [Diagram 2] FIG. 4 is an explanatory diagram showing a modified layer forming step. [Diagram 3] FIG. [Figure 4] FIG. 2 is a cross-sectional view of a seat extension device. [Diagram 5] 11 is a cross-sectional view showing a frame holding process in the chip spacing forming step. FIG. [Figure 6] 11 is a cross-sectional view showing a sheet expansion process in the chip spacing forming step. FIG. [Figure 7] 11A and 11B are cross-sectional views showing a sheet suction and holding process in a contraction step. [Figure 8] FIG. 11 is a cross-sectional view showing a retreat process of the contraction step. [Figure 9] 4A to 4C are cross-sectional views showing a sheet shrinking process in a shrinking step. [Figure 10] 4A to 4C are cross-sectional views showing a sheet shrinking process in a shrinking step. [Figure 11] FIG. 11 is an explanatory diagram showing another example of the modified layer forming step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the chip spacing forming method according to this embodiment, a wafer 100 as shown in Fig. 1 is used as a workpiece. The wafer 100 has a circular shape, and has grid-like dividing lines 103 formed on its surface. Devices 101 are formed in each of the areas partitioned by the dividing lines 103.

[0012] In this embodiment, the wafer 100 is handled in the state of a work set 110. The work set 110 is formed by integrating an annular frame 111 having an opening 112 capable of accommodating the wafer 100 with the wafer 100 positioned in the opening 112 of the annular frame 111 by an expand sheet 113. Thus, in this embodiment, the wafer 100 is supported in the opening 112 of the annular frame 111 via the expand sheet 113.

[0013] Next, each step of the chip spacing forming method according to the present embodiment will be described. This chip spacing forming method is a method for forming a predetermined spacing between a plurality of chips constituting the wafer 100.

[0014] [Modified layer formation step] 2, a laser irradiator 200 is used to irradiate the wafer 100 with a laser beam 201 along the division lines 103. This forms modified layers 202 with weak strength that serve as fracture starting points inside the wafer 100 along the division lines 103. As a result, the wafer 100 is divided by the modified layers 202 into a plurality of chips 120, each including one device 101.

[0015] [Chip spacing formation step] In this step, the expand sheet 113 of the work set 110 is expanded to form a predetermined gap between the chips 120 of the wafer 100 .

[0016] In this step, the seat extension device 4 shown in Figures 3 and 4 is used. As shown in Figure 3, the seat extension device 4 has a rectangular base 40. A frame holding member 5 that holds the annular frame 111 of the work set 110 is disposed on the upper surface of the base 40.

[0017] The frame holding member 5 has a cylindrical base 51 disposed on the upper surface of the base 40, and four clamps 52 serving as frame fixing parts disposed on the outer periphery of the upper end of the cylindrical base 51. The upper surface of the cylindrical base 51 functions as a mounting surface 511 for mounting the annular frame 111 of the work set 110. The annular frame 111 placed on the mounting surface 511 is fixed to the cylindrical base 51 by the clamps 52. In this manner, the frame holding member 5 can hold the work set 110 including the annular frame 111 and the wafer 100 .

[0018] A sheet expansion mechanism 6 for expanding an expandable sheet 113 attached to an annular frame 111 is disposed within the cylindrical base 51 of the frame holding member 5. This sheet expansion mechanism 6 comprises a holding table 62 that holds the wafer 100, an expansion drum 61 that is arranged to hold the holding table 62 from below, and a moving member 63 that moves the expansion drum 61 and the holding table 62 along the Z-axis direction.

[0019] The holding table 62 holds the wafer 100 of the work set 110 held by the frame holding member 5. The holding table 62 has a disk-shaped main body 621 and a holding surface (suction chuck) 622 arranged on the main body 621. As shown in FIG. 4, the holding surface 622 is arranged on the upper surface of the main body 621 so as to cover a main body ventilation path 623 provided in the main body 621.

[0020] The holding surface 622 has air permeability, and is connected to a suction source 637 shown in Fig. 4 to suction-hold the wafer attachment area 131 (see Fig. 1), which is the area of ​​the expand sheet 113 where the wafer 100 is attached. That is, the holding table 62 can suction-hold the wafer 100 via the expand sheet 113 by the holding surface 622. Furthermore, the holding surface 622 is configured to be in communication with an air source 638 shown in FIG. 4, so as to eject a predetermined amount (for example, a minute amount) of air.

[0021] The holding table 62 having such a configuration is supported by the expansion drum 61. 3, the expansion drum 61 has a peripheral wall 611 formed in an annular shape, and a circular bottom wall 612 covering the lower surface of the peripheral wall 611. A hole 614 penetrating the bottom wall 612 is provided in the center of the bottom wall 612. In addition, a plurality of expansion auxiliary rollers 613 are disposed on the upper end of the peripheral wall 611. As shown in FIG. 4, the upper surface of the expansion auxiliary roller 613 is disposed at approximately the same height as the holding surface 622 of the holding table 62.

[0022] The main body 621 of the holding table 62 is surrounded by the peripheral wall 611 of the expansion drum 61 with almost no gaps, and is supported on the bottom wall 612 of the expansion drum 61.

[0023] The expansion drum 61 is supported by a moving member 63 . The moving member 63 is made up of an air cylinder mechanism, and has a piston base 630, a piston rod 631 provided so as to be movable in the Z-axis direction relative to the piston base 630, and a circular support base 632 provided on the upper end of the piston rod 631. The support base 632 supports the bottom wall 612 of the expansion drum 61 from below.

[0024] Therefore, in the moving member 63, by moving the piston rod 631 in the Z-axis direction, it is possible to move the expansion drum 61 and the holding table 62 in the Z-axis direction.

[0025] A connecting pipe 635 is provided at the center of the support base 632. The connecting pipe 635 penetrates the hole 614 (see FIG. 3) in the bottom wall 612 of the expansion drum 61 and the center of the main body 621 of the holding table 62. In this way, the holding table 62 and the expansion drum 61 are supported by the support base 632 of the moving member 63 with the same connecting pipe 635 penetrating their centers.

[0026] 4, an air passage 636 is provided in the connecting pipe 635 and the piston rod 631. One end of the air passage 636 is connected to the holding surface 622 of the holding table 62 via the connecting pipe 635 and the main body air passage 623 of the holding table 62. The other end of the air passage 636 is connected to an air source 638 and a suction source 637 via the piston rod 631 and a switching valve 639.

[0027] That is, the holding surface 622 of the holding table 62 can be connected to a suction source 637 or an air source 638 via this air passage 636 .

[0028] As shown in FIG. 3, the sheet expanding device 4 further includes a heating member 8 for heating the expanding sheet 113 of the work set 110 held by the frame holding member 5. As shown in FIG.

[0029] The heating member 8 has an infrared heater 81, a support rod 82 that supports the infrared heater 81, and a rotating member 83 that rotates the support rod 82. The infrared heater 81 is formed in an annular shape with a size that corresponds approximately to the contraction region 132 (see FIG. 1) in the expand sheet 113. This contraction region 132 is the region between the wafer attachment region 131 in the expand sheet 113 and the annular frame 111, i.e., the portion of the expand sheet 113 between the inner peripheral edge of the annular frame 111 and the outer peripheral edge of the wafer 100.

[0030] The rotating member 83 rotates the infrared heater 81 between a retracted position (the position shown in FIG. 3) and a heating position. The heating position is a position above the contraction region 132 of the expand sheet 113 of the work set 110 held by the frame holding member 5.

[0031] The sheet expanding device 4 also includes a control unit 17. The control unit 17 controls the operation of each member of the sheet expanding device 4 to execute the tip spacing forming step.

[0032] The step of forming a chip gap using such a sheet expanding device 4 will be described below.

[0033] In this step, for example, an operator places the annular frame 111 of the work set 110 on the mounting surface 511 of the cylindrical base 51 of the frame holding member 5, as shown in FIG. 5, and fixes it to the cylindrical base 51 with the clamps 52 (frame holding process).

[0034] At this time, the control unit 17 controls the moving member 63 to move the piston rod 631 downward, thereby positioning the holding surface 622 of the holding table 62 and the expansion auxiliary roller 613 of the expansion drum 61 below the expand sheet 113 of the work set 110, as shown in Figure 5.

[0035] Furthermore, the control unit 17 controls the switching valve 639 to connect the holding surface 622 of the holding table 62 to the air source 638 via the air passage 636. As a result, air is ejected from the holding surface 622 of the holding table 62 installed below the expanding sheet 113, as shown by the arrow 301 in FIG.

[0036] Next, in a state where air is being ejected from the holding surface 622, the control unit 17 controls the moving member 63 to move the piston rod 631 upward as shown by the arrow 401 in Fig. 6. As a result, the control unit 17 raises the expansion drum 61 and the holding table 62 to a predetermined expansion position so that the expansion auxiliary roller 613 of the expansion drum 61 and the holding surface 622 of the holding table 62 are positioned above the mounting surface 511 of the cylindrical base 51 as shown in Fig. 6.

[0037] As a result, the expansion auxiliary rollers 613 of the expansion drum 61 come into contact with the expanding sheet 113 and push up the expanding sheet 113. This causes the expanding sheet 113 to expand (sheet expanding process). As a result, a tensile force acts radially on the wafer 100 attached to the expanding sheet 113. By this radial tensile force acting on the wafer 100, the wafer 100 is broken along the modified layer 202 formed along the intended division lines 103 and separated into individual chips 120, and a predetermined interval is formed between adjacent chips 120.

[0038] In this sheet expanding step, the holding surface 622 of the holding table 62, which is disposed at approximately the same height as the upper surface of the expansion auxiliary roller 613, also comes into contact with the expanding sheet 113. In this regard, in this embodiment, air is ejected from the holding surface 622, thereby reducing friction between the expanding sheet 113 and the holding surface 622. Therefore, the expanding sheet 113 can be easily expanded while suppressing the influence of friction with the holding surface 622, so that a predetermined interval can be satisfactorily formed between the chips 120.

[0039] Furthermore, the control unit 17 can adjust the amount of expansion (stretching) of the expand sheet 113 by controlling the amount of upward movement of the expansion drum 61 and the holding table 62. By adjusting the amount of expansion of the expand sheet 113, the control unit 17 can set the intervals formed between the individual chips 120 to predetermined intervals.

[0040] [Shrinkage Step] In this step, with a predetermined interval formed between each chip 120, the control unit 17 controls the switching valve 639 to connect the holding surface 622 of the holding table 62 to the suction source 637. As a result, as shown by the arrow 302 in Fig. 7, the control unit 17 causes the holding surface 622 to suction-hold the area of ​​the expand sheet 113 corresponding to the chip 120 (wafer bonding area 131; see Fig. 1), thereby maintaining the interval between the chips 120 (sheet suction holding process).

[0041] In this state, the control unit 17 controls the moving member 63 to move the piston rod 631 downward as shown by the arrow 402 in Fig. 8. As a result, the control unit 17 lowers the expansion drum 61 and the holding table 62 to a predetermined retreat position so that the holding surface 622 and the upper surface of the expansion auxiliary roller 613 are approximately at the same height as the mounting surface 511 of the cylindrical base 51 (retraction process).

[0042] This causes the expansion auxiliary roller 613 of the expansion drum 61 to move away from the expanding sheet 113. As a result, slack is generated in the contraction region 132, which is the region between the wafer attachment region 131 in the expanding sheet 113 and the annular frame 111 (i.e., the portion stretched on the outer periphery side of the wafer 100).

[0043] Next, the control unit 17 positions the infrared heater 81 of the heating member 8 (see FIG. 3) at a heating position above the contraction region 132 of the expanding sheet 113 as shown in FIG. 9, and turns on the infrared heater 81. As a result, the contraction region 132 of the expanding sheet 113 is heated by infrared rays irradiated by the infrared heater 81, and contracts as shown in FIG. 10 (sheet contraction process). Thus, in the shrinking step, the stretched shrink region 132 on the outer periphery side of the wafer 100 is caused to shrink by heating.

[0044] Thereafter, the control unit 17 controls the switching valve 639 to release communication between the holding surface 622 of the holding table 62 and the suction source 637. Then, for example, the operator removes the work set 110 from the frame holding member 5, and the process ends.

[0045] As described above, in this embodiment, in the chip spacing forming step, air is ejected from the holding surface 622 of the holding table 62 installed below the expanding sheet 113 to reduce friction between the expanding sheet 113 and the holding surface 622. Therefore, the wafer attachment area 131 of the expanding sheet 113 can be easily expanded, so that a predetermined spacing can be satisfactorily formed between the chips 120.

[0046] In the contraction step, the contraction region 132 in the expand sheet 113 is contracted, so that the expand sheet 113 returns to a taut state without slack, while maintaining the gap formed between the chips 120 in the chip gap forming step. Therefore, for example, when the work set 110 is transported to a pickup device (not shown), damage caused by contact between the chips 120 can be suppressed.

[0047] In this embodiment, the heating member 8 has an infrared heater 81. In this regard, the heating member 8 may have a member that blows hot air to the contraction area 132 instead of the infrared heater 81.

[0048] 2, a modified layer 202 is formed on the wafer 100 by performing a modified layer forming step before the chip gap forming step. Then, in the chip gap forming step, the wafer 100 is divided into a plurality of chips 120 starting from the modified layer 202. In this regard, in the present embodiment, the following division step may be performed instead of the modified layer forming step.

[0049] [Split Step] 11, a cutting blade 210 is used to form division grooves 212 along the division lines 103 of the wafer 100. As a result, the wafer 100 is divided by the division grooves 212 into a plurality of chips 120, each including one device 101.

[0050] In this case, before the chip spacing forming step is performed, the wafer 100 has already been divided into a plurality of chips 120. Therefore, in the chip spacing forming step, the spacing between the chips 120 on the wafer 100 is widened to a predetermined spacing.

[0051] In this case as well, in the chip spacing forming step, air is blown from the holding surface 622 of the holding table 62 to reduce friction between the expanding sheet 113 and the holding surface 622. Therefore, the wafer attachment area 131 of the expanding sheet 113 can be easily expanded, so that a predetermined spacing can be satisfactorily formed between the chips 120.

[0052] In the dividing step, the dividing grooves 212 may be formed by using a laser beam from the laser irradiator 200 shown in FIG. [Explanation of symbols]

[0053] 4: seat extension device, 17: control unit, 5: frame holding member, 40: base, 51: cylindrical base, 52: clamp, 511: mounting surface, 6: sheet expansion mechanism, 61: expansion drum, 611: peripheral wall, 612: bottom wall, 613: expansion auxiliary roller, 614: hole, 62: holding table, 621: main body, 622: holding surface, 623: main body ventilation path, 63: moving member, 630: piston base, 631: piston rod, 632: Support base; 635: Connection pipe; 636: Air passage; 637: suction source, 638: air source, 639: switching valve 8: heating member, 81: infrared heater, 82: support rod, 83: rotating member, 200: laser irradiator, 201: laser beam, 210: cutting blade, 100: wafer, 101: device, 103: division line, 110: work set, 111: annular frame, 112: opening, 113: Expanded sheet, 120: Chip, 131: wafer attachment area, 132: shrinkage area, 202: modified layer, 212: division groove

Claims

[Claim 1] A chip spacing forming method for forming a predetermined spacing between a plurality of chips constituting a workpiece supported via an expandable sheet in an opening of an annular frame, comprising: a chip spacing forming step in which, when the expand sheet comes into contact with a holding surface of a holding table installed below the expand sheet, air is ejected from the holding surface to reduce friction between the expand sheet and the holding surface, thereby expanding the expand sheet and forming a predetermined gap between the chips; a shrinking step in which, after carrying out the chip spacing forming step, the holding surface of the holding table sucks and holds the area of ​​the expanded sheet corresponding to the chip, and, while maintaining the spacing between the chips, heats a portion of the expanded sheet between the inner peripheral edge of the annular frame and the outer peripheral edge of the workpiece to shrink the portion; A method for forming a tip gap, comprising:

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