Braking method

Abstract

To provide a breaking method for reducing division failure and reducing the risk of damage to a wafer.SOLUTION: A breaking method for dividing a wafer having a dividing starting point formed along a planned dividing line along the planned dividing line, includes a protective sheet disposing step 1001 in which a protective sheet having no adhesive layer and formed to be flat on the front and back surfaces thereof is disposed on the front surface side of the wafer, an alignment step 1002 in which after the protective sheet disposing step 1001 is performed, the front surface side of the wafer is imaged from the protective sheet side, and aligning the planned dividing line and a pressing member with each other, and a dividing step 1003 in which after the alignment step 1002 is performed, the pressing member is pressed along the planned dividing line to divide the wafer along the planned dividing line.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a braking method. [Background technology]

[0002] A known method for dividing a semiconductor wafer into chips involves positioning the focal point of a laser beam with a wavelength that passes through the wafer inside the wafer and moving it along the intended dividing line to form a modified layer that serves as the starting point for dividing, and then applying an external force to this modified layer to divide the wafer (see, for example, Patent Document 1).

[0003] The wafer is divided by placing an adhesive sheet on the back surface of the wafer and a protective sheet on the front surface, and pressing a dividing blade against the protective sheet side along the intended dividing lines. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3408805 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the film used as the protective sheet has low transparency, making it difficult to align the dividing pressure blade with the intended dividing line, and there was a risk of poor dividing or damage to the wafer due to positioning the pressure blade in an incorrect position.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a breaking method that reduces division defects and reduces the risk of damage to the wafer. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the breaking method of the present invention is a breaking method for dividing a wafer, which has dividing starting points formed along a planned dividing line, along the planned dividing line, and is characterized by comprising a protective sheet disposing step of disposing a protective sheet, which has a flat front and back surface and does not have a glue layer, on the front side of the wafer, an alignment step of, after performing the protective sheet disposing step, imaging the front side of the wafer from the protective sheet side and aligning the planned dividing line with a pressing member, and a dividing step of, after performing the alignment step, pressing the pressing member along the planned dividing line to divide the wafer along the planned dividing line.

[0008] In the breaking method, the protective sheet may contain an antistatic agent.

[0009] In the breaking method, the dividing step may include clamping an area adjacent to the planned dividing line to be divided with a pair of clamping members from above and below the wafer, and pressing the wafer in the area adjacent to the planned dividing line to be divided on the opposite side of the pair of clamping members across the planned dividing line to be divided with the pressing member from the protective sheet side, thereby dividing the wafer along the planned dividing line to be divided. Effect of the Invention

[0010] The present invention has an effect of reducing division failure and reducing the risk of damage to the wafer. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view diagrammatically showing a wafer to be divided in the breaking method according to the first embodiment. FIG. [Diagram 2] FIG. 2 is a cross-sectional view that typically shows the wafer shown in FIG. [Diagram 3] FIG. 3 is a flowchart showing the flow of the braking method according to the first embodiment. [Figure 4]FIG. 4 is a cross-sectional view that illustrates a protective sheet providing step of the breaking method illustrated in FIG. [Diagram 5] FIG. 5 is a perspective view showing a schematic configuration example of a braking device for performing the alignment step and the division step of the braking method shown in FIG. [Figure 6] FIG. 6 is a perspective view showing a schematic configuration of a lower clamping unit of the clamping unit of the breaking device shown in FIG. [Figure 7] 7 is a side view, partially in section, showing a schematic configuration of an upper clamping unit of the clamping unit of the breaking device shown in FIG. 5. FIG. [Figure 8] FIG. 8 is a side view, partially in section, illustrating a pressing member of the braking device illustrated in FIG. [Figure 9] FIG. 9 is a schematic front view, partially in cross section, of the load measuring section as viewed in the direction of arrow IX shown in FIG. [Figure 10] FIG. 10 is a schematic side view, partly in section, illustrating an alignment step of the breaking method shown in FIG. [Figure 11] FIG. 11 is a schematic side view, partially in section, showing a state in which a device adjacent to a division line to be divided is clamped between clamping members in the dividing step of the breaking method shown in FIG. [Figure 12] FIG. 12 is a side view, partially in section, diagrammatically showing a state in which the workpiece is divided along a division line in the division step of the breaking method shown in FIG. [Figure 13] FIG. 13 is a side view showing a schematic cross section of an enlarged portion of the XIII portion in FIG. [Figure 14] FIG. 14 is a diagram showing an image of a wafer acquired in the alignment step of the breaking method according to the first embodiment. [Figure 15] FIG. 15 is a diagram showing an image of a wafer captured by the method of the comparative example. [Figure 16] FIG. 16 is a perspective view that diagrammatically shows a modified example of the wafer shown in FIG. [Figure 17] FIG. 17 is a cross-sectional view that typically shows the wafer shown in FIG. [Figure 18] FIG. 18 is a side view, partially in cross section, illustrating a modified example of the alignment step shown in FIG. [Figure 19] FIG. 19 is a side view, partially in cross section, typically showing a modification of the dividing step shown in FIG. [Figure 20] FIG. 20 is a side view, partially in cross section, typically showing a modification of the dividing step shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The form (embodiment) 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 embodiment. Furthermore, the components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the configurations described below can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the configurations can be made without departing from the gist of the present invention.

[0013] [Embodiment 1] The breaking method according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view that typically shows a wafer to be divided by the breaking method according to the first embodiment. FIG. 2 is a cross-sectional view that typically shows the wafer shown in FIG. 1. FIG. 3 is a flow chart showing the flow of the breaking method according to the first embodiment. The breaking method according to the first embodiment is a method for dividing the wafer 200 shown in FIG. 1 into individual chips 210.

[0014] (Wafer) The wafer 200 to be divided by the breaking method according to the first embodiment is, for example, a disk-shaped semiconductor wafer or an optical device wafer having a substrate 201 made of glass, sapphire, SiC, or the like. As shown in Fig. 1, the wafer 200 has a surface 202 on which a plurality of dividing lines 203 intersecting each other are set, and devices 204 are formed in areas partitioned by the dividing lines 203. Note that in the present invention, the wafer 200 may have a substrate 201 made of a material other than glass, sapphire, or SiC, and may not have devices 204 formed thereon.

[0015] The device 204 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), an optical element such as an LED (Light-Emitting Diode), or a memory (semiconductor memory device).

[0016] 1 and 2, the wafer 200 has a division starting point 205 formed along the division line 203. In the first embodiment, the division starting point 205 is a modified layer formed inside the substrate 201 along the division line 203. The modified layer means a region in which the density, refractive index, mechanical strength, and other physical properties are different from those of the surroundings, and examples of the modified layer include a melting process region, a crack region, a dielectric breakdown region, a refractive index change region, and a region in which these regions are mixed. The modified layer has a lower mechanical strength than other parts of the substrate 201.

[0017] In addition, in embodiment 1, as shown in Figures 1 and 2, the wafer 200 has a central portion of a disk-shaped tape 207 having a larger diameter than the wafer 200 attached to the back surface 206 behind the front surface 202, and an annular frame 208 having an inner diameter larger than the outer diameter of the wafer 200 attached to the outer edge of the tape 207.

[0018] The tape 207 is an adhesive tape including a base layer made of a non-adhesive and flexible resin and a glue layer laminated on the base layer and made of an adhesive and flexible resin, the glue layer being attached to the wafer 200 and the annular frame 208. The tape 207 is also stretchable. Thus, in the first embodiment, the wafer 200 is accommodated inside the opening 209 of the annular frame 208 by the tape 207 attached to the back surface 206.

[0019] (Braking method) The breaking method according to the first embodiment is a method of dividing a wafer 200, on which division starting points 205 are formed along division lines 203, along the division lines 203 into individual chips 210. Each chip 210 includes a part of a substrate 201 and a device 204 formed on the surface of the substrate 201. As shown in FIG. 3, the breaking method includes a protective sheet providing step 1001, an alignment step 1002, and a dividing step 1003.

[0020] (Protective sheet placement step) Fig. 4 is a cross-sectional view that shows a schematic diagram of a protective sheet disposing step of the breaking method shown in Fig. 3. The protective sheet disposing step 1001 is a step of disposing a protective sheet 220 having a flat front surface 221 and a flat back surface 222 without a glue layer on the front surface 202 side of the wafer 200.

[0021] In the first embodiment, in the protective sheet providing step 1001, a protective sheet 220 having the same diameter as the wafer 200 is placed on the front surface 202 of the wafer 200, as shown in Fig. 4. In the present invention, in the protective sheet providing step 1001, the protective sheet 220 etc. is not heated, and is not pressed against the front surface 202 of the wafer 200 while being heated to adhere to the front surface 202 of the wafer 200. In the first embodiment, the protective sheet 220 is in the shape of a disk having the same diameter as the wafer 200, but the present invention is not limited thereto, and may be formed in the shape of a disk having a larger diameter than the wafer 200.

[0022] In the first embodiment, the protective sheet 220 is a so-called adhesive-free tape made of only a base material made of a non-adhesive thermoplastic resin such as polyolefin or polyethylene. Usually, the so-called adhesive-free tape made of only a base material made of a thermoplastic resin to be attached to the wafer 200 has irregularities intentionally formed on the surface to improve handling properties, and has a surface roughness (Ra) of 1.2 μm. However, in the first embodiment, the protective sheet 220 has a front surface 221 and a back surface 222 formed flat, and the surface roughness (Ra) of the front surface 221 and the back surface 222 is 0.01 μm or more and 0.5 μm or less, preferably 0.1 μm.

[0023] In the first embodiment, the protective sheet 220 is manufactured using a general method such as cast molding. The protective sheet 220 may be manufactured by forming the surface shape of a roll used for stretching into a mirror-like shape, and transferring the mirror surface of the roll to the front surface 221 and the back surface 222. The front surface 221 and the back surface 222 of the protective sheet 220 may be flattened by a separate processing unit for flattening the surface shape, such as an air knife, separate from the roll.

[0024] In the first embodiment, the thickness of the protective sheet 220 is desirably 50 μm or more and 150 μm or less, and preferably 80 μm or more and 100 μm or less. If the protective sheet 220 is too thin, for example less than 50 μm, it is difficult to handle and the sheets stick to each other, and if the thickness is too thick, for example more than 150 μm, it is difficult to transmit the force during braking.

[0025] In the first embodiment, the protective sheet 220 has a storage modulus of 10 MPa or more and 1 GPa or less at 10° C. or more and 30° C. or less. In the present invention, the protective sheet 220 may be charged during peeling from the wafer 200, which may damage the wafer 200. Therefore, the protective sheet 220 may contain an antistatic agent (e.g., at least one of polyethylene glycol methacrylate copolymer, polyether ester amide, and polyether ester) to suppress damage to the wafer 200 during peeling. In the present invention, the protective sheet 220 may be sprayed with an antistatic spray instead of (or in addition to) the antistatic agent, to form an antistatic film on the front surface 221 and the back surface 222.

[0026] (Braking device) Next, the braking device 1 shown in FIG. 5 which performs the alignment step and the division step will be described. FIG. 5 is a perspective view which shows a typical configuration example of the braking device which performs the alignment step and the division step of the braking method shown in FIG. 3. FIG. 6 is a perspective view which shows a typical configuration of a lower clamping unit of the clamping unit of the braking device shown in FIG. 5. FIG. 7 is a side view which shows a typical configuration of an upper clamping unit of the clamping unit of the braking device shown in FIG. 5, partially in section. FIG. 8 is a side view which shows a typical configuration of a pressing member of the braking device shown in FIG. 5, partially in section. FIG. 9 is a front view which shows a typical configuration of a load measuring unit, partially in section, as seen from the direction of the arrow IX shown in FIG. 8.

[0027] The breaking device 1 shown in Fig. 5 is a device that divides a wafer 200 starting from a division starting point 205, and divides the wafer 200 into individual chips 210. As shown in Fig. 5, the breaking device 1 includes a frame fixing unit 10, a detection unit 20, a clamping unit 40, a pressing member 60, a control unit 100 which is a controller, a display unit 110, and an input unit (not shown).

[0028] The frame fixing unit 10 fixes the annular frame 208. The frame fixing unit 10 includes a movable frame 11 provided on the apparatus body 2 so as to be movable in the X-axis direction parallel to the horizontal direction by an X-axis moving unit 30, and a frame fixing member 12 disposed on the movable frame 11.

[0029] The frame fixing member 12 is formed in an annular shape with inner and outer diameters equal to those of the annular frame 208, and its upper surface serves as a holding surface 13 on which the annular frame 208 is placed via the outer periphery of the tape 207. The holding surface 13 is flat along the horizontal direction. In the first embodiment, the frame fixing member 12 has a suction hole on the holding surface 13 that is connected to a suction source (not shown).

[0030] The frame fixing unit 10 attracts and fixes the annular frame 208 placed on the holding surface 13 via the tape 207 by the suction hole being attracted by a suction source. In the present invention, when the annular frame 208 is made of a magnetic material, the frame fixing unit 10 may have a magnet (permanent magnet or electromagnet) disposed in the frame fixing member 12 and may attract and fix the annular frame 208 placed on the holding surface 13 by magnetic force, and when the annular frame 208 is made of a non-magnetic material, the frame fixing unit 10 may have a clamp mechanism that clamps the annular frame 208 between the frame fixing unit 10 and the holding surface 13 to fix the annular frame 208. The frame fixing unit 10 is rotatable around an axis parallel to the Z-axis direction (also called the vertical direction) by a rotation drive mechanism (not shown).

[0031] The X-axis moving unit 30 is installed on the device main body 2 and includes a well-known ball screw that is rotatable about its axis, a well-known motor that moves the moving frame 11 and the frame fixing member 12 in the X-axis direction by rotating the ball screw about its axis, and a well-known guide rail 31 that supports the moving frame 11 so that it is movably in the X-axis direction.

[0032] The detection unit 20 detects the planned dividing lines 203 of the wafer 200 to which the annular frame 208 is fixed by the frame fixing unit 10. The detection unit 20 is mounted on a moving table 4 that is moved by a Y-axis moving unit 32 in a Y-axis direction that is parallel to the horizontal direction and perpendicular to the X-axis direction, on a gate-shaped frame 3 that stands from the apparatus main body 2 across a guide rail 31 of an X-axis moving unit 30. The detection unit 20 is mounted on the moving table 4 so as to be freely movable in the Y-axis direction by the Y-axis moving unit 32.

[0033] The detection unit 20 includes an imaging camera 21 equipped with an imaging element such as a CCD (Charge Coupled Device) imaging element or a CMOS (Complementary MOS) imaging element that images an object facing an objective lens in the Z-axis direction parallel to the vertical direction. The detection unit 20 acquires an image captured by the imaging element and outputs the acquired image to the control unit 100. The detection unit 20 also acquires an image of the wafer 200 accommodated in an opening 209 of an annular frame 208 fixed by the frame fixing unit 10, and acquires an image for performing alignment for aligning the planned dividing line 203 of the wafer 200 with the pressing member 60, etc.

[0034] The gate-shaped frame 3 and the moving table 4 are flat plates with both surfaces parallel to the Z-axis direction which is parallel to the vertical direction, and are stacked in parallel with a gap between them. The Y-axis moving unit 32 is installed on the gate-shaped frame 3 and includes a well-known ball screw rotatable about its axis, a well-known motor which moves the moving table 4 in the Y-axis direction by rotating the ball screw about its axis, and a well-known guide rail 33 which supports the moving table 4 movably in the Y-axis direction.

[0035] The clamping unit 40 clamps the devices 204 of the wafer 200 from above and below along the Z-axis direction in an area adjacent to the planned division lines 203 along which the wafer 200 is to be divided. The clamping unit 40 includes a lower clamping unit 41 and an upper clamping unit 50, as shown in FIG.

[0036] The lower clamping unit 41 is disposed below the frame fixing unit 10, and presses from below a device 204 which is an area adjacent to a planned division line 203 along which the wafer 200 is to be divided and which is accommodated in an opening 209 of an annular frame 208 fixed to the frame fixing unit 10. As shown in Fig. 6, the lower clamping unit 41 includes a bracket 42 which is provided so as to be movable up and down in the Z-axis direction by the Z-axis moving unit 34, a rotating body 43 which is supported by the bracket 42 so as to be rotatable about its axis, and a plurality of rectangular clamping members 44 which protrude from the outer circumferential surface of the rotating body 43 and have different lengths.

[0037] The rotating body 43 is disposed with its axis parallel to the Y-axis direction, and both ends are rotatably supported by brackets 42. The rotating body 43 is rotated around its axis by a rotation mechanism (not shown). The rectangular clamping members 44 are each formed as a linear rectangular plate with a constant thickness in the Y-axis direction, and are formed to have various lengths in the Y-axis direction. The longest of the rectangular clamping members 44 has a length equal to the length of the longest planned dividing line 203 of the wafer 200, and the shortest rectangular clamping member 44 has a length equal to the length of the shortest planned dividing line 203 of the wafer 200.

[0038] The direction of protrusion of the rectangular clamping members 44 is changed by the rotation of the rotating body 43. When the rectangular clamping members 44 arranged upward from the rotating body 43 along the Z-axis direction are lowered by the Z-axis moving unit 34, the upper end of the rectangular clamping members 44 is located below the tape 207 attached to the wafer 200 accommodated in the opening 209 of the annular frame 208 fixed by the frame fixing unit 10, and when the rectangular clamping members 44 are raised by the Z-axis moving unit 34, the upper end of the rectangular clamping members 44 is located above the wafer 200 accommodated in the opening 209 of the annular frame 208 fixed by the frame fixing unit 10. When the rectangular clamping members 44 arranged upward from the rotating body 43 along the Z-axis direction are raised by the Z-axis moving unit 34, the upper end of the rectangular clamping members 44 presses the device 204 adjacent to the division line 203 along which the wafer 200 should be divided upward from the back surface 206 side.

[0039] In other words, the lower clamping unit 41 can select the length of the upwardly facing rectangular clamping member 44 by changing the orientation around the axis of the rotating body 43, and the selected rectangular clamping member 44 presses upwardly from the back surface 206 side of the device 204 adjacent to the planned division line 203 along which the wafer 200 is to be divided.

[0040] In addition, the Z-axis moving unit 34 is equipped with a well-known ball screw that is freely rotatable around its axis, a well-known motor that raises and lowers the bracket 42 in the Z-axis direction by rotating the ball screw around its axis, and a well-known guide rail 35 that supports the bracket 42 so that it can be raised and lowered in the Z-axis direction.

[0041] The upper clamping unit 50 is disposed above the frame fixing unit 10, and clamps, between the upper clamping unit 50 and the lower clamping unit 41, a device 204 that is adjacent to a planned dividing line 203 along which the wafer 200 is to be divided and that is accommodated in an opening 209 of an annular frame 208 fixed by the frame fixing unit 10 and that is pressed from below by the lower clamping unit 41. The upper clamping unit 50 is installed on the movable base 5. The movable base 5 is moved in the Z-axis direction by a lifting unit 36 ​​installed on the movable table 4.

[0042] The movable base 5 is formed in a flat plate shape with both surfaces parallel to the Z-axis direction, and is stacked with a gap between them on the movable table 4. A horizontal member 6 with both surfaces parallel to the horizontal direction is fixed to the movable base 5.

[0043] The lifting unit 36 ​​is installed on the movable table 4 and includes a well-known ball screw that is rotatable around its axis, a well-known motor 37 that raises and lowers the movable base 5 in the Z-axis direction by rotating the ball screw around its axis, and a well-known guide rail 38 that supports the movable base 5 so that it can be raised and lowered in the Z-axis direction.

[0044] 7, the upper clamping unit 50 includes a cylinder unit 51, an upper clamping member 52, and a slide unit 53. The cylinder unit 51 includes a cylinder 54 fixed to the horizontal member 6, and a rod 55 formed in a bar shape parallel to the Z-axis direction, which is extendable from the cylinder 54 and has a lower end that descends when extended from the cylinder 54.

[0045] The upper clamping member 52 is formed in a rectangular plate shape having a constant thickness, a straight line in the Y-axis direction, and both surfaces parallel to the Z-axis direction, and the length in the Y-axis direction is equal to the length of the longest planned dividing line 203 of the wafer 200. The upper clamping member 52 has the lower end of the rod 55 of the cylinder unit 51 fixed to its upper end, and is stacked on the movable base 5 with a gap therebetween. The upper clamping member 52 faces the rectangular clamping member 44 facing upward from the rotating body 43 in the Z-axis direction.

[0046] Further, the slide unit 53 supports the upper clamping member 52 so as to be slidable in the Z-axis direction relative to the movable base 5. The slide unit 53 includes a linear guide rail 56 that is fixed to the movable base 5, which is one of the movable base 5 and the upper clamping member 52, and is parallel to the Z-axis direction, and a slider 57 that is fixed to the upper clamping member 52, which is the other of the movable base 5 and the upper clamping member 52, and is supported on the guide rail 56 so as to be slidable in the longitudinal direction of the guide rail 56, i.e., in the Z-axis direction.

[0047] When the upper clamping member 52 is raised by the lifting unit 36 ​​with the rod 55 extended, its lower end is positioned above the wafer 200 accommodated in the opening 209 of the annular frame 208 fixed by the frame fixing unit 10, and when it is lowered by the lifting unit 36, its lower end clamps between the rectangular clamping member 44 and the device 204 adjacent to the planned dividing line 203 to be divided of the wafer 200 pressed by the rectangular clamping member 44 which is arranged upward from the rotating body 43 along the Z-axis direction.

[0048] The pressing member 60 presses the devices 204 of the wafer 200 in an area adjacent to the dividing line 203 on the opposite side in the Y-axis direction of the clamping members 44, 52 of the clamping unit 40 across the dividing line 203, thereby breaking (also called dividing) the wafer 200 along the dividing line 203. The pressing member 60 is installed on a pressing and moving base 62 that is installed on the horizontal member 6 so as to be movable in the X-axis direction by a second X-axis moving unit 61, as shown in FIG.

[0049] The pressing movement base 62 has both surfaces parallel to the Z-axis direction, is integrally formed with a thick portion 63 on the upper end side and a thin portion 64 on the lower end side, and is stacked on the upper clamping member 52 with a gap therebetween. In the first embodiment, the pressing movement base 62 has the thick portion 63 and the thin portion 64 formed in the same plane on the surface away from the upper clamping member 52, and a step is formed between the thick portion 63 and the thin portion 64 on the upper clamping member 52 side. Also, in the first embodiment, the pressing movement base 62 has an opening 65 having a rectangular planar shape penetrating the thin portion 64.

[0050] The second X-axis moving unit 61 is installed on the horizontal member 6 and includes a well-known ball screw that is rotatable around its axis, a well-known motor 66 that moves the pressing moving base 62 in the X-axis direction by rotating the ball screw around its axis, and a well-known guide rail 67 that supports the pressing moving base 62 so that it can move freely in the Z-axis direction.

[0051] The pressing member 60 is formed in a rectangular plate shape that is linear in the Y-axis direction and has both surfaces parallel to the Z-axis direction, and the length in the Y-axis direction is equal to the length of the longest planned division line 203 of the wafer 200. The pressing member 60 has a tapered portion 68 formed at its lower end such that the thickness gradually decreases toward the bottom. In the first embodiment, the tapered portion 68 has a surface on the upper clamping member 52 side that is formed flat along the Z-axis direction, and a surface on the side away from the upper clamping member 52 that is inclined with respect to both the horizontal direction and the Z-axis direction in a direction gradually approaching the upper clamping member 52 as it approaches downward.

[0052] The pressing member 60 is supported on the pressing moving base 62 by a pair of slide units 69 so as to be slidable in the Z-axis direction. The pair of slide units 69 are arranged at an interval in the Y-axis direction. The slide unit 69 includes a linear guide rail 691 fixed to the pressing moving base 62, which is one of the pressing moving base 62 and the pressing member 60, and parallel to the Z-axis direction, and a slider 692 fixed to the pressing member 60, which is the other of the pressing moving base 62 and the pressing member 60, and supported on the guide rail 691 so as to be slidable in the longitudinal direction of the guide rail 691, i.e., in the Z-axis direction.

[0053] When the pressing member 60 is raised by the lifting unit 36, it is positioned above the wafer 200 accommodated in the opening 209 of the annular frame 208 whose lower end is fixed by the frame fixing unit 10, and when it is lowered by the lifting unit 36, it presses downward the device 204 of the wafer 200 that positions the division line 203 to be divided between the clamping members 44, 52 in the Y-axis direction. In the first embodiment, the pressing member 60 presses downward a position of the wafer 200 where the distance in the Y-axis direction from the upper clamping member 52 is about 75% to 85% of the width of the chip 210. In the present invention, the pressing member 60 may press downward a position of the wafer 200 where the distance in the Y-axis direction from the upper clamping member 52 is about 65% to 95% of the width of the chip 210.

[0054] If the position pressed by the pressing member 60 is too close in the Y-axis direction from the upper clamping member 52, the wafer is less likely to break, and if it is too far away, the pressing member 60 escapes to the already broken dividing line 203 side and does not break, so it is preferable that the pressing member 60 presses downward a position where the distance in the Y-axis direction from the upper clamping member 52 of the wafer 200 is about 65% to 95% of the width of the chip 210, and preferably a position where the distance in the Y-axis direction from the upper clamping member 52 of the wafer 200 is about 75% to 85% of the width of the chip 210. When the pressing member 60 is lowered by the lifting unit 36, it presses downward in the Y-axis direction the device 204 of the wafer 200 that positions the dividing line 203 to be divided between the clamping members 44, 52, thereby dividing the dividing line 203 to be divided.

[0055] Moreover, the pressing member 60 is fixed to the pressing movement base 62 by a load measuring unit 70 shown in Fig. 8. The load measuring unit 70 is disposed between a pair of slide units 69. As shown in Figs. 8 and 9, the load measuring unit 70 includes a load meter 71 that measures the value of the load (hereinafter referred to as the load value) with which the pressing member 60 presses the wafer 200, a holding member 72, a support member 73, a spring 75, and a support unit 74 (shown only in Fig. 9).

[0056] The load meter 71 measures the load value with which the pressing member 60 in the Z-axis direction presses the wafer 200, and is a well-known load cell in the first embodiment, but is not limited to a load cell. The load meter 71 outputs the load value, which is the measurement result, to the control unit 100. The load meter 71 is disposed in the opening 65 of the pressing movement base 62.

[0057] The holding member 72 has one end fixed to the pressing member 60, extends from the pressing member 60 toward the pressing movable base 62, and has the other end disposed within the opening 65 of the pressing movable base 62. The holding member 72 supports the lower end of the load meter 71 at the other end.

[0058] The support member 73 is disposed within the opening 65 of the pressing movable base 62, with its upper end fixed to the upper inner surface of the opening 65 and its lower end supporting the upper end of the load meter 71. The support part 74 is disposed within the opening 65 of the pressing movable base 62, with its lower end fixed to the lower inner surface of the opening 65 and its upper end supporting the lower end of the holding member 72.

[0059] The spring 75 is disposed between the lower inner surface of the opening 65 and the other end of the holding member 72, and urges the pressing member 60 upward relative to the pressing movement base 62 via the other end of the holding member 72. In the first embodiment, the spring 75 urges the holding member 72 and the pressing member 60 upward with a force corresponding to the combined mass of the pressing member 60, the holding member 72, and the load meter 71. By the spring 75 urging with the above-mentioned force, the combined mass of the pressing member 60, the holding member 72, and the load meter 71 is offset, and the load meter 71 can measure a load value smaller than the combined mass of the pressing member 60, the holding member 72, and the load meter 71. In this way, the breaking device 1 includes the load meter 71 that measures the load value with which the pressing member 60 presses the wafer 200.

[0060] The control unit 100 controls each of the above-mentioned components of the breaking device 1 to cause the breaking device 1 to perform a dividing operation for dividing each of the dividing lines 203 of the wafer 200. The control unit 100 is a computer having an arithmetic processing device having a microprocessor such as a CPU (central processing unit), a storage device having a memory such as a ROM (read only memory) or a RAM (random access memory), and an input / output interface device. The arithmetic processing device of the control unit 100 performs arithmetic processing according to a computer program stored in the storage device, and outputs a control signal for controlling the breaking device 1 to each of the above-mentioned units of the breaking device 1 via the input / output interface device. The control unit 100 also determines a dividing result of the dividing lines 203 based on a load value measured by the load meter 71, and stores the dividing result in a one-to-one correspondence with the dividing lines 203.

[0061] The display unit 110 is connected to the control unit 100 and includes a display screen 111 that displays various information. The input unit is used when an operator inputs information, etc. to the control unit 100 of the braking device 1. The input unit is connected to the control unit 100 and outputs the input information to the control unit 100. The input unit includes a touch panel overlaid on the display screen 111 of the display unit 110.

[0062] (Alignment step) Next, the alignment step 1002 will be described. Fig. 10 is a side view, partially in cross section, showing the alignment step of the breaking method shown in Fig. 3. The alignment step 1002 is a step of imaging the front surface 202 side of the wafer 200 from the protective sheet 220 side after the protective sheet providing step 1001 is performed, and aligning the planned dividing line 203 with the pressing member 60.

[0063] In the first embodiment, in the alignment step 1002, first, an operator or the like operates the input unit to input the division conditions, and the control unit 100 accepts and registers the division conditions. In the first embodiment, in the alignment step 1002, when the control unit 100 accepts an instruction to start the division operation from the operator or the like, the braking device 1 starts the division operation, that is, the alignment step 1002 in the first embodiment.

[0064] In the first embodiment, in the alignment step 1002, the control unit 100 of the braking device 1 controls the Z-axis moving unit 34 to lower the lower clamping unit 41, controls the cylinder unit 51 of the upper clamping unit 50 to extend the rod 55, and controls the lifting unit 36 ​​to lift the upper clamping unit 50 and the pressing member 60. Also, in the first embodiment, in the alignment step 1002, the control unit 100 of the braking device 1 controls the second X-axis moving unit 61 to adjust the position of the pressing member 60 in the X-axis direction so that the distance in the X-axis direction between the lower end of the upper clamping member 52 and the lower end of the pressing member 60 is 75% to 85% of the width of the chip 210 included in the division condition. Note that, in the present invention, it is sufficient to adjust the position of the pressing member 60 in the X-axis direction so that the distance in the X-axis direction between the lower end of the upper clamping member 52 and the lower end of the pressing member 60 is 65% to 95% of the width of the chip 210.

[0065] Also, in the embodiment 1, in the alignment step 1002, the control unit 100 of the braking apparatus 1 controls the X-axis moving unit 30 to retract the frame fixing unit 10 from between the clamping units 41, 50. In the embodiment 1, in the alignment step 1002, the annular frame 208 having the wafer 200 accommodated in the opening 209 is placed on the holding surface 13 of the frame fixing unit 10. In the embodiment 1, in the alignment step 1002, the control unit 100 of the braking apparatus 1 operates the suction source to suck and fix the annular frame 208 to the holding surface 13 of the frame fixing unit 10.

[0066] In the embodiment 1, in the alignment step 1002, the control unit 100 of the braking device 1 controls the X-axis moving unit 30 and the Y-axis moving unit 32 to position the detection unit 20 above the planned dividing line 203 (hereinafter, denoted by reference numeral 203-1) to be divided, based on the dividing order of the dividing conditions, as shown in Fig. 10, and captures an image of the periphery of the planned dividing line 203-1 including the planned dividing line 203-1 of the wafer 200 with the imaging camera 21 of the detection unit 20. In the embodiment 1, in the alignment step 1002, the braking device 1 detects the planned dividing line 203-1 based on the image captured by the control unit 100 with the imaging camera 21 of the detection unit 20.

[0067] In embodiment 1, in the alignment step 1002, the braking device 1 has the control unit 100 control the rotation mechanism to position the rectangular clamping member 44 having a length corresponding to the planned dividing line 203 upward from the rotating body 43, and controls the rotation drive mechanism to position the planned dividing line 203-1 of the wafer 200 parallel to the Y-axis direction. 10)。 In the first embodiment, in the dividing step 1003, the control unit 100 of the braking device 1 controls the X-axis moving unit 30 to position the lower end of the upper clamping member 52 above the device 204 (corresponding to an area and hereinafter referred to as 204-1 in FIG. 10) adjacent to the planned division line 203-1 on the far side in the X-axis direction in FIG. 1, position the upper end of the rectangular clamping member 44 below the device 204-1 on the far side in the X-axis direction in FIG. 1 adjacent to the planned division line 203-1 on the far side in the X-axis direction in FIG. 1, and position the lower end of the pressing member 60 above the device 204 (corresponding to an area and hereinafter referred to as 204-2 in FIG. 10) adjacent to the planned division line 203-1 on the near side in the X-axis direction in FIG. 1, thereby aligning the planned division line 203-1 with the pressing member 60.

[0068] (split step) Fig. 11 is a side view, partly in section, showing a state in which a device adjacent to a division line to be divided is clamped between clamping members in the division step of the breaking method shown in Fig. 3. Fig. 12 is a side view, partly in section, showing a state in which the division line to be divided is divided in the division step of the breaking method shown in Fig. 3. Fig. 13 is a side view, partly in section, showing an enlarged portion of part XIII in Fig. 12.

[0069] The dividing step 1003 is a step of dividing the wafer 200 along the dividing lines 203-1 by pressing the pressing member 60 along the dividing lines 203-1 after the alignment step 1002 is performed. The dividing step 1003 is also a step of clamping the device 204-1, which is an area adjacent to the dividing lines 203-1 to be divided, with the pair of clamping members 44, 52 from above and below the wafer 200, and pressing the device 204-2 of the wafer 200 in the area adjacent to the dividing lines 203-1 to be divided on the opposite side of the pair of clamping members 44, 52 with the dividing lines 203-1 to be divided, from the protective sheet 220 side with the pressing member 60, thereby dividing the wafer 200 along the dividing lines 203-1 to be divided.

[0070] In the embodiment 1, in the dividing step 1003, the control unit 100 of the breaking device 1 controls the Z-axis moving unit 34 to raise the rotating body 43 and the rectangular clamping member 44, and presses the device 204-1 adjacent to the dividing line 203-1 of the wafer 200 upward via the tape 207. Then, the wafer 200 rises, and the device 204-1 abuts against the lower end of the upper clamping member 52 via the protective sheet 220. Thus, in the embodiment 1, in the dividing step 1003, the breaking device 1 clamps the device 204-1 adjacent to the dividing line 203-1 of the wafer 200 between the clamping members 44, 52 via the protective sheet 220 and the tape 207, as shown in FIG. 11. At this time, in the embodiment 1, the lower end of the pressing member 60 is located above the surface 202 of the wafer 200.

[0071] In the first embodiment, in the dividing step 1003, the control unit 100 of the breaking device 1 controls the lifting unit 36 ​​based on the dividing conditions to lower the movable base 5 and the pressing member 60 of the upper clamping unit 50. Then, since the upper clamping member 52 holds the device 204-1 adjacent to the planned dividing line 203-1 of the wafer 200 between itself and the rectangular clamping member 44 via the protective sheet 220 and the tape 207, the upper clamping member 52 does not lower, and the rod 55 of the cylinder unit 51 contracts, causing the upper clamping member 52 to rise relative to the movable base 5 by the slide unit 53.

[0072] In addition, when the movable base 5 and pressing member 60 of the upper clamping unit 50 descend, the pressing member 60 descends and the lower end of the pressing member 60 abuts against the device 204-2 adjacent to the planned division line 203-1 on the opposite side of the clamping units 41, 50 on the surface 202 of the wafer 200 via the protective sheet 220, and the pressing member 60 descends further and, as shown in Figures 12 and 13, the lower end of the pressing member 60 is positioned lower than the lower end of the upper clamping member 52, thereby dividing the planned division line 203-1 between the clamping members 44, 52 and the pressing member 60.

[0073] In embodiment 1, in the splitting step 1003, the control unit 100 in the braking device 1 lowers the movable base 5 and the pressing member 60 in accordance with the splitting conditions, and then controls the lifting unit 36 ​​to raise the movable base 5 and the pressing member 60, and controls the Z-axis moving unit 34 to lower the rotating body 43 and the rectangular clamping member 44.

[0074] In the first embodiment, in the dividing step 1003, the control unit 100 determines the dividing result of the dividing line 203-1 to be divided based on the load value measured by the load meter 71, and stores the determined dividing result in association with the dividing line 203-1. In the first embodiment, in the dividing step 1003, the breaking device 1 divides the wafer 200 along the dividing lines 203 in order from the end dividing line 203 based on the dividing conditions. In the first embodiment, in the dividing step 1003, the breaking device 1 divides all the dividing lines 203 of the wafer 200 and divides the wafer 200 into individual chips 210, and then ends the dividing operation, i.e., the dividing step 1003. Thereafter, the divided chips 210 are picked up from the tape 207.

[0075] In the breaking method according to the embodiment 1 described above, since the front surface 221 and the back surface 222 of the protective sheet 220 arranged on the front surface 202 side of the wafer 200 in the protective sheet arrangement step 1001 are flat, the planned division line 203-1 can be detected in the alignment step 1002 without thermocompression bonding the protective sheet 220, and alignment can be performed.

[0076] As a result, the breaking method according to the first embodiment has the effect of reducing the number of defective divisions of the wafer 200 and reducing the risk of damage to the wafer 200 when the protective sheet 220 is peeled off.

[0077] Next, the effect of the breaking method according to embodiment 1 was confirmed. Fig. 14 is a diagram showing an image of a wafer acquired in an alignment step of the breaking method according to embodiment 1. Fig. 15 is a diagram showing an image of a wafer acquired by imaging using a method of a comparative example.

[0078] Fig. 14 shows an image 300 of the front surface 202 of the wafer 200 captured by the imaging camera 21 when a protective sheet 220 having a surface roughness (Ra) of 0.1 µm on the front surface 221 and back surface 222 is disposed on the back surface 206 side of the wafer 200. Fig. 15 shows an image 301 of the front surface 202 of the wafer 200 captured by the imaging camera 21 when a protective sheet 220 having a surface roughness (Ra) of 1.2 µm on the front surface 202 side of the wafer 200 is disposed on the front surface 202 side of the wafer 200.

[0079] 15, it was difficult to detect the device 4, i.e., the planned division line 203-1, from the image 301. In contrast to this comparative example, according to the breaking method of the first embodiment shown in FIG. 14, it was possible to detect the device 4, i.e., the planned division line 203-1, from the image 300.

[0080] Therefore, according to Figures 14 and 15, it has become clear that by disposing protective sheet 220 having a surface roughness (Ra) of 0.01 μm or more and 0.5 μm or less on front surface 202 of wafer 200 without thermocompression bonding, alignment can be achieved, failure to separate wafer 200 can be reduced, and the risk of damage to wafer 200 when protective sheet 220 is peeled off can be reduced.

[0081] The breaking method according to the first embodiment also includes a protective sheet providing step 1001 of providing the protective sheet 220 on the front surface 202 side of the wafer 200. For this reason, in the breaking method according to the first embodiment, in the dividing step 1003, the wafer 200 is pressed by the pressing member 60 via the protective sheet 220 in a state in which the protective sheet 220 is in close contact with the front surface 202 of the wafer 200, so that there is no risk of the division debris 211 entering between the front surface 202 of the wafer 200 and the protective sheet 220.

[0082] As a result, the breaking method according to the first embodiment has the effect of suppressing damage to the wafer 200 during division.

[0083] Furthermore, in the breaking method according to embodiment 1, the protective sheet 220 is a so-called adhesive-free tape composed only of a base material made of a non-adhesive thermoplastic resin, so that after the protective sheet 220 is removed, no resin constituting the adhesive layer remains on the surface of the device 204.

[0084] The present invention is not limited to the above embodiment. In other words, various modifications can be made without departing from the gist of the present invention. For example, in the present invention, the tape 207 may be a sheet that does not have a glue layer, like the protective sheet 220, but is made of only a base material made of a thermoplastic resin, and exhibits adhesive strength when heated.

[0085] 16 and 17, in the present invention, recessed grooves may be formed in the front surface 202 of the wafer 200 as starting points 205-1 along the dividing lines 203. The grooves are formed by cutting the dividing lines 203 or by irradiating the dividing lines 203 with a laser beam having a wavelength that is absorbent for the wafer 200.

[0086] Fig. 16 is a perspective view showing a schematic modification of the wafer shown in Fig. 1. Fig. 17 is a cross-sectional view showing a schematic modification of the wafer shown in Fig. 16. In Figs. 16 and 17, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0087] 18, in the alignment step 1002, for example, the front surface 202 of the wafer 200 may be placed on the support base 15 of the breaking device 1-1 via a protective sheet 220, and the front surface 202 of the wafer 200 may be imaged via the protective sheet 220 by the imaging camera 21 between the support bases 15. In this case, as shown in Fig. 19 and Fig. 20, the back surface 206 side of the intended dividing line 203-1 is pressed by a pressing member 60 via a tape 207 to divide the wafer 200.

[0088] Fig. 18 is a side view, partially in cross section, typically showing a modified example of the alignment step shown in Fig. 10. Fig. 19 is a side view, partially in cross section, typically showing a modified example of the division step shown in Fig. 11. Fig. 20 is a side view, partially in cross section, typically showing a modified example of the division step shown in Fig. 12. In Figs. 18, 19 and 20, the same reference numerals are assigned to the same parts as in embodiment 1, and description thereof will be omitted. [Explanation of symbols]

[0089] 44 Rectangular clamping member (clamping member) 52 Upper clamping member (clamping member) 60 Pressing member 200 wafers 202 Surface 203 Division line 203-1 Planned division line to be divided 204 Devices 204-1 Device (area) 204-2 Device (area) 205,205-1 Split starting point 220 Protective Sheet 221 Surface 222 Back side 1001 Protective sheet placement step 1002 Alignment Step 1003 division steps

Claims

1. A breaking method for dividing a wafer along a planned dividing line, the breaking method comprising the steps of: a protective sheet disposing step of disposing a protective sheet having no adhesive layer and having a flat front and back surface on the front surface side of the wafer; an alignment step of imaging the front surface side of the wafer from the protective sheet side after the protective sheet disposing step is performed, and aligning the division line with a pressing member; a dividing step of dividing the wafer along the dividing lines by pressing the pressing member along the dividing lines after performing the alignment step; A braking method comprising:

2. 2. The breaking method according to claim 1, wherein the protective sheet contains an antistatic agent.

3. The dividing step is characterized in that an area adjacent to a division line to be divided is sandwiched between a pair of sandwiching members from above and below the wafer, and the wafer in the area adjacent to the division line to be divided is pressed by the pressing member from the protective sheet side on the opposite side of the pair of sandwiching members across the division line to be divided, thereby dividing the wafer along the division line to be divided. The braking method according to claim 1 or 2.

Images