Wafer dividing method
By forming a modified layer and pressing the wafer from both sides, the method addresses the issue of undivided areas in wafer division, enhancing the division efficiency and chip production yield.
Patent Information
- Application Number
- JP2023109383
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-07-03
- Publication Date
- 2025-01-17
AI Technical Summary
Existing wafer dividing methods using breaking techniques often result in undivided areas due to cracks propagating in a single direction, making it difficult to effectively divide wafers into chips.
A wafer dividing method that involves forming a modified layer inside the wafer as a starting point for division, and then pressing the wafer from both the front and back sides to propagate cracks in opposite directions, ensuring complete separation along the planned dividing lines.
This method effectively reduces undivided areas and improves the division ratio by ensuring cracks propagate across the entire wafer, facilitating efficient chip production.
Smart Images
Figure 2025007773000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a method for dividing a wafer. [Background technology]
[0002] Known examples of breaking techniques for breaking and dividing a wafer having division starting points formed therein include a technique using a breaking roller as described in Patent Document 1 and a technique using a breaking blade as described in Patent Document 2.
[0003] These breaking techniques have in common that a crack is generated from the division starting point by pressing the wafer, and the wafer is broken and divided by the crack. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] JP 2023-032665 A [Patent Document 2] Patent No. 6232323 Summary of the Invention [Problem to be solved by the invention]
[0005] By employing the above breaking technology to divide the wafer, the possibility of undivided regions occurring on the wafer can be significantly reduced compared to when the wafer is divided only by tape expanding.
[0006] However, even with breaking techniques, undivided regions may occur, and further improvements are required. The present invention has been made in view of the above, and has an object to divide a wafer well by breaking. [Means for solving the problem]
[0007] A wafer dividing method according to one embodiment of the present invention is a wafer dividing method for dividing a wafer to produce a plurality of chips, and includes a wafer preparation step of preparing a wafer having a division starting point formed along a planned division line, a first crack propagation step of pressing the wafer, whose back side is held by a holding portion, from the front side of the wafer to cause the crack to propagate from the division starting point, and a second crack propagation step of pressing the wafer, whose front side is held by the holding surface, from the back side to cause the crack to propagate from the division starting point, and a wafer dividing step of breaking the wafer and dividing it into a plurality of chips. Effect of the Invention
[0008] According to the present invention, the wafer can be divided well by breaking. [Brief description of the drawings]
[0009] [Figure 1] FIG. 2 is a perspective view showing a wafer surface. [Diagram 2] FIG. 4 is a perspective view showing a modified layer forming step. [Diagram 3] FIG. 11 is an explanatory diagram showing a protective tape applying step. [Figure 4] FIG. 1 is an explanatory diagram showing a conventional division step. [Diagram 5] FIG. 13 is an explanatory diagram showing the relationship between a roller and a crack. [Figure 6] FIG. 1 is an explanatory diagram showing a crack propagation step that constitutes a division step in roller breaking. [Figure 7] FIG. 13 is an explanatory diagram showing another crack propagation step that constitutes the division step in roller breaking. [Figure 8] FIG. 13 is an explanatory diagram showing the relationship between a blade and a crack. [Figure 9] FIG. 11 is an explanatory diagram showing a first dividing step constituting a dividing step in blade breaking. [Figure 10] FIG. 11 is an explanatory diagram showing a second dividing step that constitutes a dividing step in blade breaking. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] (First embodiment) A wafer dividing method according to the present embodiment will be described with reference to the drawings. FIG. 1 is a perspective view showing a wafer. The wafer 10 shown in FIG. 1 is a semiconductor wafer of, for example, silicon, gallium arsenide, or the like, and is formed in a substantially plate shape. A surface 11 of the wafer 10 is partitioned into a plurality of regions by lattice-shaped dividing lines 13, and devices 12 are formed in each region. The wafer 10 is not limited to a semiconductor wafer, and may be a ceramic, glass, or sapphire-based optical device wafer.
[0011] The wafer dividing method according to the present embodiment is a wafer in which dividing starting points are formed along the dividing line, and is typically performed on a wafer in which protective tape is attached to each of the front and back surfaces of the wafer, but may be performed on a wafer without protective tape. The protective tape is a support member that supports the wafer, and is fixed to at least one of the front and back surfaces of the wafer. In the following, an example of forming a modified layer, which is an example of a dividing starting point, on the wafer will be described. The dividing starting points formed on the wafer are not limited to modified layers, and may be scribe lines or the like. However, the wafer dividing method according to the present embodiment is particularly effective for a modified layer, which functions as a starting point for propagating cracks toward both the front and back surfaces of the wafer formed inside the wafer.
[0012] Fig. 2 is a perspective view showing the modified layer forming step. The modified layer forming step shown in Fig. 2 is performed by a laser processing device 20. In the modified layer forming step, the wafer 10 is held on a holding table 21 of the laser processing device 20 via a protective tape 15. The holding table 21 is, for example, a chuck table that holds the wafer 10 by suction. The protective tape 15 is attached in advance to the front surface 11 of the wafer 10 to protect the device 12.
[0013] Moreover, the irradiation unit 22 of the laser processing device 20 is positioned on the planned dividing line 13 of the wafer 10 so that the focal point is located inside the wafer 10. The laser beam 23 emitted from the irradiation unit 22 is irradiated onto the wafer 10 from the back surface 14 side of the wafer 10, and a modified layer is formed by multiphoton absorption occurring at the focal point inside the wafer 10.
[0014] The irradiation unit 22 repeats movement along the planned division lines 13 by a horizontal movement mechanism (not shown) and irradiation with the laser beam 23, thereby forming modified layers along the planned division lines 13. Furthermore, the irradiation unit 22 is sequentially positioned on other planned division lines 13 parallel to the planned division lines 13 already irradiated with the laser beam 23 by a horizontal movement mechanism (not shown), and the above-mentioned process is repeated for each planned division line 13, so that modified layers are finally formed along all of the planned division lines 13.
[0015] The modified layer formed inside the wafer 10 is more fragile than other regions of the wafer 10. For this reason, the modified layer functions as a starting point for dividing the wafer 10 when a load is applied to the wafer 10 in order to divide the wafer 10.
[0016] In the wafer dividing method according to the present embodiment, the wafer is handled in a state of a work set in which the wafer and an annular frame are integrated by, for example, a dicing tape. In the following, an example of forming a work set by adhering a dicing tape, which is an example of a protective tape, will be described.
[0017] Fig. 3 is an explanatory diagram showing the dicing tape application step. The dicing tape application step shown in Fig. 3 is an example of a step of fixing a support member performed by a tape application device 30. In the dicing tape application step, first, the frame 17 is placed on the holding table 31 of the tape application device 30, and then the wafer 10 is placed inside the circular opening of the frame 17 with the front surface 11 facing the holding table 31.
[0018] Furthermore, the dicing tape 18 is placed so as to cover the opening of the frame 17 with the adhesive surface facing the wafer 10. Finally, the roller 32 rolls from end to end on the surface opposite to the adhesive surface of the dicing tape 18, thereby adhering the dicing tape 18 to the frame 17 and the back surface 14 of the wafer 10. This forms a work set 19. Note that the modified layer 16 formed inside the wafer 10 is shown in FIG. 3.
[0019] An example has been shown in which a modified layer 16 is formed inside the wafer 10 by the laser processing apparatus 20 and then a work set 19 is formed by the tape application apparatus 30, but it is also possible to form a modified layer 16 inside the wafer 10 by the laser processing apparatus 20 after forming the work set 19 by the tape application apparatus 30.
[0020] Fig. 4 is an explanatory diagram showing a conventional dividing step. Fig. 5 is an explanatory diagram showing the relationship between a roller and a crack. In the following, the conventional dividing step will be described with reference to Figs. 4 and 5 in order to clarify the difference from the dividing step according to the present embodiment described later.
[0021] The conventional dividing step is performed by a breaking device 40 shown in Fig. 4. In this dividing step, first, the work set 19 is placed on the holding table 41 of the breaking device 40 with the front surface 11 of the wafer 10 to which the protective tape 15 is attached facing the holding table 41. The holding table 41 then holds the work set 19.
[0022] The holding table 41 may hold the work set 19 by, for example, clamping the frame 17 with a clamp (not shown), or the holding table 41 may hold the wafer 10 by suction via the protective tape 15. The holding table 41 may hold the work set 19 by performing both of these operations.
[0023] Thereafter, the breaking device 40 presses the wafer 10 via the dicing tape 18 with the roller 42 of the breaking device 40 to divide the wafer 10. More specifically, the breaking device 40 rolls the roller 42 from one end of the frame 17 to the other end on the surface opposite to the adhesive surface of the dicing tape 18 so as to cross the opening of the frame 17 as shown by the arrow 43 in Fig. 4, thereby applying a vertical load to the wafer 10 when the roller 42 passes over the wafer 10. As a result, a crack 161 is generated starting from the modified layer 16 due to stress generated in the wafer 10, and the wafer 10 is broken along the planned division line 13 and divided into a plurality of chips.
[0024] The roller 42 has a length equal to or greater than the diameter of the wafer 10, for example. Therefore, the roller 42 can press the entire area of the wafer 10 by crossing the opening of the frame 17. However, in the conventional dividing step, even though the entire area of the wafer 10 is pressed, an undivided area where division is not performed on the wafer 10 may be generated.
[0025] The present inventors have thoroughly investigated the cause of the occurrence of undivided regions in the dividing step, and have found that in many cases, in the undivided regions of the wafer 10, the cracks 161 progress from the modified layer 16 to the front surface 11 held on the holding table 51, as shown in Fig. 5, but do not progress from the modified layer 16 to the back surface 14. In other words, it has been found that the cracks 161 tend to progress from the modified layer 16 in the same direction as the vertical pressing force applied to the wafer 10 by the rollers 42 (vertically downward in this example), but do not tend to progress in the opposite direction (vertically upward in this example).
[0026] The inventors of the present application concluded that the above phenomenon is caused by pressing the wafer 10 only from one of the front surface 11 and the back surface 14, and invented a division method in which pressing from both the front surface 11 and the back surface 14 is performed in sequence, thereby generating cracks 161 evenly from the modified layer 16 to both the front surface 11 side and the back surface 14 side.
[0027] The above phenomenon indicating that the crack 161 is likely to progress in the same direction as the pressing force (vertically downward in this example) can be explained by the fact that, if it is assumed that the wafer 10 is bent around the modified layer 16, a tensile stress is generated radially outward on the outer side of the modified layer 16 relative to the roller 42 (i.e., on the front surface 11 side), and a compressive stress is generated radially inward on the inner side of the modified layer 16 of the wafer 10 (on the back surface 14 side). Also, if it is assumed that the wafer 10 is bent around the contact point with the roller 42 on the back surface 14 or a position on the roller 42 side, it can be explained by the fact that a larger tensile stress is generated radially outward as it approaches the front surface 11 from the back surface 14. In other words, regardless of whether it is assumed that the bending center is inside, on the surface, or outside the wafer 10, the fact that the crack 161 is likely to progress in the same direction as the pressing force due to the stress generated in the wafer 10 remains unchanged, and this supports the above phenomenon.
[0028] FIG. 6 is an explanatory diagram showing a crack propagation step constituting the division step in roller breaking. FIG. 7 is an explanatory diagram showing another crack propagation step constituting the division step in roller breaking. Hereinafter, the division step in the wafer division method according to the present embodiment will be described with reference to FIG. 6 and FIG. 7. Note that roller breaking refers to a breaking method in which the wafer is divided by pressing the wafer with a roller. In this example, the wafer is pressed with a roller via a protective tape attached to the wafer, but the wafer may be pressed without the protective tape.
[0029] The dividing step is a wafer dividing step for dividing the wafer 10, and is performed by the breaking device 50 shown in FIG. 6 and FIG. 7. The dividing step is performed on the wafer 10 on which a dividing starting point is formed along the dividing line. Here, an example will be described in which the dividing step is performed on the wafer 10 on which the protective tape 15, which is the first protective tape, is attached to the front surface 11 and the dicing tape 18, which is the second protective tape, is attached to the back surface 14. That is, before the dividing step, a wafer preparation step for preparing the wafer 10 on which a dividing starting point is formed is performed, and in this wafer preparation step, the wafer 10 on both sides of which the protective tape is attached may be prepared. The wafer preparation step may include, for example, a modified layer formation step performed by the laser processing device 20 described above and a dicing tape attachment step performed by the tape attachment device 30. In addition, in the wafer preparation step, the wafer 10 on which the protective tape is attached to at least one of the front surface and the back surface may be prepared. In other words, the wafer preparation step may include a step of fixing a support member to at least one of the front and back surfaces of the wafer. The starting point of division is, for example, the modified layer 16.
[0030] In the dividing step, the breaking device 50 presses the wafer 10 with the roller 52 via the protective tape to break the wafer 10 along the dividing lines 13 (modified layer 16) to divide the wafer 10. In detail, in the dividing step, the breaking device 50 performs a first crack developing step (see FIG. 7) in which the wafer 10, the back surface 14 of which is held by the holding table 51, which is a holding unit of the breaking device 50, is pressed from the front surface 11 to cause a crack 163 to develop from the modified layer 16, and a second crack developing step (see FIG. 6) in which the wafer 10, the back surface 11 of which is held by the holding table 51, is pressed from the back surface 14 to cause a crack 162 to develop from the modified layer 16.
[0031] In the division step, it is sufficient that both the first crack propagation step and the second crack propagation step are performed, and it does not matter which of the first crack propagation step and the second crack propagation step is performed first.
[0032] The dividing step will be described in more detail below. First, the work set 19 is placed on the holding table 51 with the front surface 11 of the wafer 10, to which the protective tape 15 is attached, facing the holding table 51, and the holding table 51 holds the wafer 10 from the front surface 11 side.
[0033] 6, the breaking device 50 rolls the roller 52 from one end to the other end of the frame 17 so as to cross the opening of the frame 17 while pressing the wafer 10 held from the front surface 11 side on the holding table 51 from the back surface 14 side via the dicing tape 18 with the roller 52 (see arrow 53). As a result, the crack 162 progresses from the modified layer 16 at least toward the front surface 11 side, and reaches the front surface 11.
[0034] Next, with the back surface 14 of the wafer 10, to which the protective dicing tape 18 is attached, facing the holding table 51, the work set 19 is placed on the holding table 51, and the holding table 51 holds the wafer 10 from the back surface 14 side.
[0035] 7, the breaking device 50 rolls the roller 52 from one end of the wafer 10 to the other end while pressing the wafer 10 held on the back surface 14 side on the holding table 51 from the front surface 11 side with the roller 52 via the protective tape 15 (see arrow 54). As a result, a crack 163 advances from the modified layer 16 to at least the back surface 14 side and reaches the back surface 14. As a result, in the division step, a crack 164 is formed that crosses the wafer 10 from the front surface 11 to the back surface 14, and the wafer 10 is broken along the division line 13 by the crack 164.
[0036] In the dividing method according to the present embodiment described above, the dividing step includes a step of pressing the wafer 10 from the front surface 11 side and a step of pressing the wafer 10 from the back surface 14 side, so that the cracks are surely propagated from the modified layer 16 to both surfaces of the wafer 10. This makes it possible to form a crack 164 that crosses the wafer 10 and reaches the back surface 14 from the front surface 11 via the modified layer 16, so that the occurrence of undivided regions in the dividing step can be suppressed compared to the conventional method, and the division rate of the wafer 10 can be improved. Therefore, according to the dividing method according to the present embodiment, the wafer 10 can be divided well by roller breaking.
[0037] In the present embodiment, as shown in Fig. 6 and Fig. 7, an example has been shown in which the roller 52 moves on the dicing tape 18 or the protective tape 15 while pressing the wafer 10 with the roller 52, but the roller 52 may move relatively to the wafer 10. More specifically, in the first crack propagation step, the roller 52 may move relatively to the wafer 10 while pressing the front surface 11 side of the wafer 10 with the roller 52, and in the second crack propagation step, the roller 52 may move relatively to the wafer 10 while pressing the back surface 14 side of the wafer 10 with the roller 52. Therefore, the holding table 51 may move in the horizontal direction while the roller 52 is stopped while pressing the wafer 10 with the roller 52.
[0038] Although not specifically mentioned in this embodiment, it is preferable that the holding table 51 has a holding surface made of an elastic member and holds the wafer 10 on the holding surface. When the wafer 10 is held on the holding surface made of an elastic member, the wafer 10 sinks into the holding surface and bends, that is, is deflected, so that a large stress is generated in the wafer 10. This promotes the development of cracks, so that the wafer 10 can be efficiently broken, and as a result, the generation of undivided regions can be suppressed. However, the holding surface of the holding table 51 is not limited to an elastic member. For example, the protective tape 15 or dicing tape 18 provided between the holding surface and the wafer 10 may play a role in forming a space into which the wafer 10 sinks, and this allows sufficient stress to be generated in the wafer 10 even if the holding surface does not sink. In addition, the holding surface does not need to hold the entire wafer 10, and it is sufficient that the holding surface holds at least the region where the roller 52 is pressed.
[0039] Second embodiment The dividing method according to this embodiment is different from the dividing method according to the first embodiment in that a blade is used instead of a roller for breaking. FIG. 8 is an explanatory diagram showing the relationship between the blade and the crack in blade breaking, in which the blade is pressed against the wafer on which the dividing starting point is formed to divide the wafer. As shown in FIG. 8, even in blade breaking, the crack 161 tends to progress from the modified layer 16 in the same direction (vertically downward in this example) as the vertical pressing force applied by the blade 62 to the wafer 10, and is difficult to progress in the opposite direction (vertically upward in this example). The reason is the same as in the case of roller breaking. Therefore, the present invention is also applicable when blade breaking is used instead of roller breaking to divide the wafer 10.
[0040] Fig. 9 is an explanatory diagram showing a first division step constituting the division step in blade breaking. Fig. 10 is an explanatory diagram showing a second division step constituting the division step in blade breaking. Hereinafter, the division method according to this embodiment will be specifically described with reference to Figs. 9 and 10.
[0041] The dividing step is a wafer dividing step for dividing the wafer 10, and is performed by a breaking device 70 shown in FIG. 9 and FIG. 10. The dividing step is performed on the wafer 10 on which a dividing starting point is formed along the planned dividing line, more specifically, on the wafer 10 on which the protective tape 15, which is the first protective tape, is attached to the front surface 11 and the dicing tape 18, which is the second protective tape, is attached to the back surface 14. That is, as in the case of roller breaking, a wafer preparation step may be performed before the dividing step to prepare the wafer 10 on which a dividing starting point is formed with protective tape attached to both sides. The dividing starting point is, for example, the modified layer 16.
[0042] In the dividing step, the breaking device 70 breaks the wafer 10 along the dividing lines 13 (modified layer 16) by pressing the wafer 10 with the blade 73 via the protective tape, dividing the wafer 10. Note that in the dividing step, the first crack propagation step (see FIG. 10) and the second crack propagation step (see FIG. 11) are performed in the same manner as in blade breaking. The order of the first crack propagation step and the second crack propagation step does not matter either way.
[0043] The dividing step in blade breaking will be described in more detail below. First, the frame 17 is placed on the frame support 71 with the front surface 11 of the wafer 10, to which the protective tape 15 is attached, facing the wafer support 72, and the frame support 71 holds the frame 17, for example, by a clamp (not shown).
[0044] Thereafter, the breaking device 70 presses the back surface 14 of the wafer along each of the planned dividing lines with the blade 73. Specifically, the following process is performed for each planned dividing line. First, the frame support part 71 rotates so that the planned dividing line and the blade 73 are parallel. Furthermore, the blade 73 moves in the horizontal direction so that the planned dividing line is positioned directly below the blade 73. The movement of the blade 73 may be performed based on an image of the wafer 10 taken by a camera (not shown), for example, and the blade 73 is thus accurately positioned on the planned dividing line. Furthermore, the wafer support part 72 that supports the wafer 10 moves in the horizontal direction in conjunction with the movement of the blade 73. The wafer support part 72, which is provided on the opposite side of the wafer 10 to the blade 73 with a predetermined support point distance therebetween, moves so that the blade 73 is positioned midway between two points of the wafer 10 supported by the wafer support part 72. As a result, the front surface 11 of the wafer 10 is held by the wafer support 72. When the movement of the wafer support 72 and the blade 73 is completed, the blade 73 descends and presses the wafer 10 from the back surface 14 side via the dicing tape 18, as shown in Fig. 9. As a result, the crack 162 advances from the modified layer 16 on the intended division line toward at least the front surface 11 side, and reaches the front surface 11.
[0045] Once the above process has been performed for each of the planned dividing lines, the frame 17 is placed on the frame support portion 71 with the back surface 14 of the wafer 10, to which the protective dicing tape 18 is attached, facing the wafer support portion 72, and the frame support portion 71 holds the frame 17.
[0046] Thereafter, the breaking device 70 presses the front surface 11 side of the wafer 10 along each of the dividing lines with the blade 73. Specifically, the following process is performed for each dividing line. First, the frame support 71 rotates so that the dividing line and the blade 73 are parallel to each other. Furthermore, the blade 73 moves horizontally to position the dividing line directly below the blade 73. Furthermore, the wafer support 72 moves horizontally in conjunction with the movement of the blade 73, and the blade 73 is positioned at the midpoint between two points of the wafer 10 supported by the wafer support 72. As a result, the back surface 14 of the wafer 10 is held by the wafer support 72. When the movement of the wafer support 72 and the blade 73 is completed, the blade 73 descends and presses the wafer 10 from the front surface 11 side via the protective tape 15, as shown in FIG. 10. As a result, the cracks 163 progress from the modified layer 16 on the intended dividing line toward at least the rear surface 14 side, and reach the rear surface 14 .
[0047] By the above process, a crack 164 is formed that crosses the wafer 10 from the front surface 11 to the back surface 14, and the wafer 10 is broken along the intended division lines 13 by the crack 164.
[0048] As described above, in the dividing method according to the present embodiment, which uses blade breaking, the dividing step includes a step of pressing the wafer 10 from the front surface 11 side and a step of pressing the wafer 10 from the back surface 14 side, so that the cracks are sure to advance from the modified layer 16 to both sides of the wafer 10. This makes it possible to form a crack 164 that crosses the wafer 10 and reaches the back surface 14 from the front surface 11 via the modified layer 16, so that the occurrence of undivided regions in the dividing step can be suppressed compared to the conventional method, and the division rate of the wafer 10 can be improved. Therefore, according to the dividing method according to the present embodiment, the wafer 10 can be divided well by blade breaking.
[0049] In this embodiment, as shown in Figures 9 and 10, an example is shown in which the blade 73 and the wafer support part 72 are moved relative to the wafer 10 in order to align the blade 73 with the planned dividing line. However, instead of moving the blade 73 and the wafer support part 72, the wafer 10 may be moved, or the frame support part 71 may be moved to move the wafer 10.
[0050] In addition, in this embodiment, an example has been shown in which cracks are generated in the modified layer 16 by three-point bending using the wafer support parts 72 arranged with a gap therebetween, but the structure for holding the wafer 10 is not limited to a structure for performing three-point bending. The entire wafer 10 or the area pressed by the blade 73 may be held on a flat table such as the holding table 51 in the first embodiment. In this case, it is preferable that the holding surface of the table is made of an elastic material, but it is not necessarily limited to an elastic material, as in the first embodiment.
[0051] The embodiments of the present invention are not limited to the above-mentioned embodiments and modifications, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea of the present invention. Furthermore, if the technical idea of the present invention can be realized in a different way due to technological progress or other derived technology, it may be implemented using that method. Therefore, the claims cover all embodiments that may be included within the scope of the technical idea of the present invention.
[0052] In the above-mentioned embodiment, the support member for supporting the wafer shown as the protective tape may be an adhesive tape having a base layer having flexibility and non-adhesiveness and an adhesive layer laminated on the base layer and having flexibility and adhesiveness, or may be a sheet made of a thermoplastic resin without an adhesive layer. When the support member is a sheet having no adhesiveness, a polyolefin sheet, a polyethylene sheet, a polypropylene sheet, or a polystyrene sheet is preferable, and the sheet is attached to the frame or the wafer by thermocompression bonding. In addition, the support member may have a form in which the wafer 10 is covered with a liquid resin and then cured, or may be formed by absorbing the unevenness of the wafer 10 with the liquid resin to cover it flat, fixing a sheet to the liquid resin, and curing the liquid resin.
[0053] The support member, which is a protective tape, may be provided on only one of the front and back surfaces, or on both surfaces. The support member is useful for transporting the chips together after division, but is not essential, and the above-mentioned division method may be performed on the wafer without providing the support member. The support member is also useful for preventing damage to the wafer due to contact with the rollers and damage to the holding table due to direct contact between the wafer and the holding table. [Industrial Applicability]
[0054] As described above, according to the wafer dividing method of the present invention, pressing from both sides of the wafer 10 can eliminate uneven crack propagation and suppress the occurrence of undivided regions in the dividing step. Therefore, the wafer 10 can be divided well, and is useful for manufacturing chips by dividing the wafer 10. [Explanation of symbols]
[0055] 10 wafers 11 Surface 12 Devices 13 Division line 14 Back side 15 Protective Tape 16 Modification layer 17 Frame 18 Dicing tape 19 Worksets 20 Laser processing equipment 21, 31, 41, 51 Holding table 22 Irradiation unit 23 Laser Beam 30 Tape application device 32, 42, 52 Roller 40, 50, 70 Braking device 62, 73 Blades 71 Frame support 72 Wafer support 161, 162, 163, 164 Crack
Claims
1. A wafer dividing method for manufacturing a plurality of chips by dividing a wafer, comprising the steps of: A wafer preparation step of preparing a wafer having division starting points formed along a planned division line; a first crack propagation step of pressing the wafer, the back surface side of which is held by a holding part, from the front surface side of the wafer to propagate a crack from the division starting point; and a second crack propagation step of pressing the wafer, the back surface side of which is held by the holding part, from the back surface side to propagate the crack from the division starting point, and a wafer dividing step of breaking the wafer and dividing it into a plurality of chips. A method for dividing a wafer, comprising the steps of:
2. the splitting starting point is a modified layer formed inside the wafer, In the first crack propagation step, the crack propagates from the division starting point to the back surface side, In the second crack propagation step, the crack propagates from the splitting starting point toward the surface side.
2. The method for dividing a wafer according to claim 1, wherein the step of dividing the wafer comprises the steps of:
3. In the first crack propagation step, the roller is moved relative to the wafer while pressing the front surface side of the wafer with the roller, In the second crack propagation step, the roller is moved relative to the wafer while pressing the back side of the wafer with the roller.
3. The method for dividing a wafer according to claim 1 or 2.
4. In the first crack propagation step, a blade is used to press the front surface side of the wafer along each of the division lines; In the second crack propagation step, the blade is pressed against the back side of the wafer along each of the dividing lines.
3. The method for dividing a wafer according to claim 1 or 2.
5. The wafer preparation step includes: and a step of fixing a support member to at least one of the front surface and the back surface of the wafer.
3. The method for dividing a wafer according to claim 1 or 2.
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