Method for manufacturing multiple chips

Abstract

A method for manufacturing a plurality of chips is provided, which reduces the possibility of processing defects as compared with the case where a workpiece is divided by applying only tensile stress or load-based stress to the workpiece. The method for manufacturing a plurality of chips has the following steps: a pasting step of pasting an expandable tape on the workpiece; a shield tunnel forming step of irradiating a pulsed laser beam having a wavelength that is transmissive to the workpiece from the back side of the workpiece along each division predetermined line in such a manner that the condensing region of the pulsed laser beam is positioned inside the workpiece, thereby forming a plurality of shield tunnels each having a fine hole and a metamorphic region surrounding the fine hole along each division predetermined line; and a dividing step of, after the shield tunnel forming step, applying ultrasonic waves to the workpiece via a liquid and expanding the tape, thereby dividing the workpiece along a plurality of division predetermined lines.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a plurality of chips by processing a plate-shaped workpiece. Background Art

[0002] As a method for dividing a workpiece such as a disk-shaped wafer having devices or the like formed on the front side along a dicing line, a method is known in which a modified layer having a lower strength than other regions is formed along the dicing line and then an external force is applied to the workpiece (for example, see Patent Document 1).

[0003] To form the modified layer, for example, a pulsed laser beam having a wavelength that is transmissive to the wafer is irradiated along the dicing line of the wafer such that the focal point is positioned inside the wafer. Thereby, multiphoton absorption occurs near the focal point inside the wafer, and a modified layer with reduced mechanical strength is formed along the dicing line.

[0004] However, for example, in order to divide a relatively thick wafer of more than 100 μm along a dicing line, it is usually necessary to form a plurality of modified layers in an overlapping manner in the depth direction of the wafer. For example, in the case of forming three modified layers in an overlapping manner in the depth direction of the wafer, with the depth position of the focal point positioned at the first depth position, a laser beam is irradiated along the dicing line (first pass).

[0005] Next, with the depth position of the focal point positioned at the second depth position closer to the front side than the first depth position, a laser beam is irradiated along the dicing line (second pass). Further, with the depth position of the focal point positioned at the third depth position closer to the front side than the second depth position, the laser beam is irradiated along the dicing line again (third pass).

[0006] Thus, in the method of forming the modified layer, it is usually necessary to irradiate the laser beam along the dicing line multiple times, so there is a problem that the processing takes time. Therefore, as a processing method for reducing the number of passes, a method has been proposed in which a modified region called a shield tunnel having fine holes and a deteriorated region surrounding the fine holes is formed along the dicing line of the wafer (for example, see Patent Document 2).

[0007] When forming a shield tunnel along the dicing line, a condenser lens having a value (S(=NA / N)) obtained by dividing the numerical aperture (NA) by the refractive index (N) of the wafer of, for example, 0.05 or more and 0.2 or less is used to converge the laser beam. After setting the S value in this way, the converging region of the pulsed laser beam having a wavelength that is transmissive to the wafer is positioned inside the wafer.

[0008] For example, if the condensing region is positioned at a specified depth of the wafer and a pulsed laser beam is irradiated from the back side of the wafer, one shield tunnel can be formed from the front surface to the back surface of the wafer. Therefore, if the condensing region is positioned at a specified depth position and a pulsed laser beam is irradiated along the division predetermined line (i.e., by irradiation of the laser beam in one pass), a plurality of shield tunnels are formed along the division predetermined line.

[0009] If a plurality of shield tunnels are formed along the division predetermined line by irradiation of the laser beam in one pass like this, compared with the case where a plurality of modified layers are formed in a manner of overlapping in the thickness direction of the wafer, there is an advantage that the time required for processing can be reduced.

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-192367

[0011] Patent Document 2: Japanese Patent Application Laid-Open No. 2014-221483

[0012] As a method for reliably dividing a wafer in which a plurality of shield tunnels are formed along the division predetermined line, for example, there is a method of pasting a resin sheet having expandability on the front side of the wafer and stretching the sheet in the radial direction of the wafer. The wafer is stretched outward in the radial direction together with the sheet and is divided.

[0013] In addition, for example, as a method for reliably dividing a wafer in which a plurality of shield tunnels are formed along the division predetermined line, there is a method of pressing a pressing member such as a breaking knife against the division predetermined line and applying a load to the wafer. The wafer is divided by the stress applied in the thickness direction along the division predetermined line.

[0014] However, in the case of dividing the workpiece (i.e., the object to be processed) in which a plurality of shield tunnels are formed only by applying tensile stress or stress based on a load to the workpiece, in order to reliably perform the division, it is necessary to apply a certain degree of larger stress to the workpiece. Therefore, the possibility of processing defects such as chipping or cracking occurring in the workpiece is increased. Summary of the Invention

[0015] The present invention has been completed in view of this problem, and an object thereof is to provide a method for manufacturing a plurality of chips, which can reduce the possibility of processing defects occurring when dividing a workpiece in which a plurality of shield tunnels are formed along a division predetermined line, compared with the case of dividing the workpiece by applying only tensile stress or stress based on a load to the workpiece.

[0016] According to one aspect of the present invention, there is provided a method for manufacturing a plurality of chips. The method divides a workpiece having a plurality of regions on the front side divided by a plurality of intersecting division predetermined lines along the plurality of division predetermined lines to manufacture a plurality of chips. The method includes the following steps: a pasting step of pasting an extensible tape on the workpiece; a shield tunnel forming step of irradiating a pulsed laser beam having a wavelength transmissive to the workpiece from the back side of the workpiece along each division predetermined line so that the condensing region of the laser beam is positioned inside the workpiece, thereby forming a plurality of shield tunnels each having a fine hole and a metamorphic region surrounding the fine hole along each division predetermined line; and a dividing step of, after the shield tunnel forming step, applying ultrasonic waves to the workpiece via a liquid and expanding the tape to divide the workpiece along the plurality of division predetermined lines.

[0017] Preferably, in the dividing step, the tape is expanded while applying ultrasonic waves to the workpiece via a liquid, so as to divide the workpiece along the plurality of division predetermined lines. Additionally, preferably, the liquid is water.

[0018] In the method for manufacturing a plurality of chips according to one aspect of the present invention, after forming shield tunnels along the division predetermined lines of the workpiece in the shield tunnel forming step, ultrasonic waves are applied to the workpiece via a liquid, and an extensible tape pasted on the workpiece is expanded, thereby dividing the workpiece.

[0019] Thus, in the dividing step of the present invention, not only a tensile stress via the tape is applied to the workpiece, but also ultrasonic waves are applied to the workpiece, thereby promoting the destruction of the shield tunnels. Therefore, even if the tensile stress is reduced, the workpiece can be divided. Accordingly, compared with the case of dividing the workpiece by applying only a tensile stress to the workpiece, the possibility of processing defects can be reduced. Description of the Drawings

[0020] Figure 1 (A) is a perspective view of the workpiece, Figure 1 and (B) is a perspective view of the workpiece unit.

[0021] Figure 2 is a perspective view of the laser processing apparatus.

[0022] Figure 3 (A) is a partially sectional side view of the workpiece etc. when the processing head and the chuck table are relatively moved, Figure 3 and (B) is a partially sectional side view of the workpiece etc. after the processing head and the chuck table are relatively moved.

[0023] Figure 4(A) is a perspective view showing the structure of a shield tunnel. Figure 4 (B) is a cross-sectional view showing a part of a workpiece in which a plurality of shield tunnels are formed along a dividing line.

[0024] Figure 5 (A) is a partially cut-away side view of an ultrasonic application device or the like. Figure 5 (B) is a view showing a case where ultrasonic waves are applied to a workpiece through a liquid. Figure 5 (C) is a view showing a case where a dicing tape is expanded while ultrasonic waves are applied to a workpiece through a liquid.

[0025] Figure 6 is a flowchart showing a method of manufacturing a plurality of chips according to the first embodiment.

[0026] Figure 7 (A) is a partially cut-away side view of an ultrasonic application device or the like. Figure 7 (B) is a partially cut-away side view of a dicing device or the like. Figure 7 (C) is a view showing a case where a dicing tape is expanded using a dicing device.

[0027] Reference Signs

[0028] 2: Laser processing device; 4: Base; 6: Base portion; 8: Wall portion; 10: Chuck table; 10a: Holding surface; 11: Workpiece; 11a: Front surface; 11b: Back surface; 11c: Notch; 11d: Shield tunnel; 11e: Fine hole; 11f: Metamorphic region; 12: Laser beam irradiation unit; 12a: Processing head; 12b: Imaging unit; 13: Dividing line; 15: Device; 15a: Device region; 15b: Outer peripheral remaining region; 16: Y-axis moving unit; 17: Dicing tape; 18: Y-axis guide rail; 19: Ring-shaped frame; 20: Y-axis moving table; 21: Workpiece unit; 22: Y-axis ball screw; 23: Chip; 24: Y-axis pulse motor; 26: X-axis moving unit; 28: X-axis guide rail; 30: X-axis moving table; 32: X-axis ball screw; 34: X-axis pulse motor; 36: Support table; 38: Ultrasonic application device; 40: Liquid; 42: Container; 44: Leg; 44a: Support portion; 46: Clamping unit; 48: Lifting device; 48a: Leg; 48b: Lifting member; 50: Ultrasonic generating unit; 52: Ultrasonic application device; 54: Leg; 54a: Support portion; 56: Clamping unit; 58: Lifting device; 58a: Leg; 58b: Lifting member; 60: Dicing device; L: Laser beam. Detailed Embodiment

[0029] An embodiment of one aspect of the present invention will be described with reference to the accompanying drawings. Figure 1(A) is a perspective view of the workpiece 11. The workpiece 11 is a wafer in a disk shape with a circular front surface 11a and a circular back surface 11b, and is formed to have a thickness of about 500 μm to 1000 μm.

[0030] The workpiece 11 is formed of, for example, sapphire, various glasses, etc. In addition, various glasses include, for example, fused silica glass, borosilicate glass, aluminosilicate glass, soda-lime glass, and non-alkali glass. In addition, the workpiece 11 may be formed of a semiconductor material such as silicon (Si).

[0031] On the front surface 11a side of the workpiece 11, a plurality of dicing lines (scribe lanes) 13 are set in a crosswise manner (for example, in a grid pattern). In the present embodiment, devices 15 are respectively set in a plurality of regions divided by the plurality of dicing lines 13. However, the devices 15 are not essential. The devices 15 may not be provided in each region divided into a rectangular shape by the dicing lines 13 arranged in a grid pattern.

[0032] An outer peripheral remaining region 15b where the devices 15 are not provided exists outside the device region 15a so as to surround the outer periphery of the device region 15a where a plurality of devices 15 are provided. A notch 11c indicating the crystal orientation of the wafer is provided at a part of the outer peripheral end of the workpiece 11. In addition, other marks such as an orientation flat may be provided instead of the notch 11c.

[0033] The workpiece 11 is processed, for example, in a state of being fixed to the opening of a metal ring-shaped frame 19 by means of a dicing tape 17 (i.e., in the state of the workpiece unit 21). Figure 1 (B) is a perspective view of the workpiece unit 21.

[0034] The dicing tape 17 is an expandable resin film. The dicing tape 17 has a laminated structure including an adhesive layer (having adhesiveness) and a base material layer (not having adhesiveness) not shown. The adhesive layer is, for example, an ultraviolet-curable resin layer provided on the entire surface of one side of the resin base material layer. When ultraviolet rays are irradiated on the adhesive layer, the adhesive force of the adhesive layer decreases, and the protective tape is easily peeled off from the workpiece 11.

[0035] The ring-shaped frame 19 has an opening with a diameter larger than the diameter of the workpiece 11. In a state where the workpiece 11 is disposed in the opening, the adhesive layer side of the dicing tape 17 is pasted on the front surface 11a side of the workpiece 11 and one surface of the ring-shaped frame 19, thereby forming the workpiece unit 21.

[0036] In the present embodiment, the workpiece 11 is processed using a laser processing device 2. Figure 2It is a perspective view of the laser processing apparatus 2. The laser processing apparatus 2 has a base 4 that supports each structure. The base 4 includes a rectangular parallelepiped-shaped base portion 6 and a wall portion 8 that protrudes upward (e.g., +Z direction) at one end (e.g., -Y direction) in the Y-axis direction (indexing feed direction) of the base portion 6.

[0037] A chuck table 10 is disposed above the base portion 6. A plurality of jig units are fixed to the outer peripheral side surface of the chuck table 10. For example, when looking down at the chuck table 10, one jig unit is provided at each of the 0 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions of a clock.

[0038] A Y-axis moving unit 16 that moves the chuck table 10 in the Y-axis direction is provided below the chuck table 10 (e.g., -Z direction). The Y-axis moving unit 16 has a pair of Y-axis guide rails 18 that are fixed to the upper surface of the base portion 6 and are parallel to the Y-axis direction.

[0039] A Y-axis moving table 20 is slidably provided on the Y-axis guide rails 18. A nut portion (not shown) is provided on the back side (lower surface side) of the Y-axis moving table 20, and a Y-axis ball screw 22 that is disposed parallel to the Y-axis guide rails 18 is rotatably coupled to the nut portion.

[0040] A Y-axis pulse motor 24 is coupled to one end of the Y-axis ball screw 22. When the Y-axis ball screw 22 is rotated by the Y-axis pulse motor 24, the Y-axis moving table 20 moves in the Y-axis direction along the Y-axis guide rails 18.

[0041] An X-axis moving unit 26 that moves the chuck table 10 in the X-axis direction perpendicular to the Y-axis direction is provided on the front side (upper surface side) of the Y-axis moving table 20. The X-axis moving unit 26 has a pair of X-axis guide rails 28 that are fixed to the upper surface of the Y-axis moving table 20 and are parallel to the X-axis direction.

[0042] An X-axis moving table 30 is slidably provided on the X-axis guide rails 28. A nut portion (not shown) is provided on the back side (lower surface side) of the X-axis moving table 30, and an X-axis ball screw 32 that is disposed parallel to the X-axis guide rails 28 is rotatably coupled to the nut portion.

[0043] An X-axis pulse motor 34 is coupled to one end of the X-axis ball screw 32. When the X-axis ball screw 32 is rotated by the X-axis pulse motor 34, the X-axis moving table 30 moves in the X-axis direction along the X-axis guide rails 28.

[0044] On the front side (upper surface side) of the X-axis moving stage 30, a support stage 36 is provided. On the upper part of the support stage 36, a substantially disk-shaped chuck table 10 is arranged. The chuck table 10 is connected to a rotation drive source (not shown) provided below and is configured to be rotatable by this rotation drive source.

[0045] On the front side of the chuck table 10, a disk-shaped porous plate formed of porous ceramics or the like is provided. The porous plate is connected to a suction source (not shown) such as an ejector through a flow path (not shown) provided inside the chuck table 10. An attractive force is generated on the front surface (i.e., the holding surface 10a) of the porous plate by the negative pressure generated by the suction source.

[0046] Above the chuck table 10, a laser beam irradiation unit 12 is provided. One end of the laser beam irradiation unit 12 is fixed to the surface on the other side (e.g., the +Y direction) in the Y-axis direction at the upper part of the wall portion 8.

[0047] At the other end of the laser beam irradiation unit 12, a processing head 12a is provided. A pulsed laser beam is irradiated substantially vertically from the processing head 12a toward the holding surface 10a.

[0048] On the one side (-X direction) in the X-axis direction of the laser beam irradiation unit 12, a photographing unit 12b is provided. The photographing unit 12b has an objective lens (not shown) for the incident of reflected light from the subject. The reflected light from the subject is guided to a photographing element (not shown) of the photographing unit 12b via the objective lens and the like.

[0049] Next, use Figure 1 of (B), Figure 3 of (A), Figure 3 of (B), Figure 4 of (A), Figure 4 of (B), Figure 5 of (A), Figure 5 of (B), Figure 5 of (C) and Figure 6 to describe the manufacturing method of the chip. Figure 6 is a flowchart showing the method of manufacturing a plurality of chips according to the first embodiment.

[0050] In the manufacturing method of the chip according to the first embodiment, first, as shown in Figure 1 of (B), a dicing tape 17 is pasted on the front surface 11a side of the workpiece 11 and one surface of the annular frame 19 to form a workpiece unit 21 (pasting step (S10)).

[0051] In the pasting step (S10), a tape pasting device (not shown) is used. The tape pasting device has a support table (not shown) for supporting the workpiece 11 and the annular frame 19. In addition, a stepped structure corresponding to the difference in thickness between the workpiece 11 and the annular frame 19 is provided on the outer peripheral portion of the support table.

[0052] When the workpiece 11 and the annular frame 19 are placed on the support table in such a manner that the back surface 11b of the workpiece 11 and the other surface of the annular frame 19 are in contact with the front surface of the support table, the difference in thickness is filled by the stepped structure, and the front surface 11a of the workpiece 11 and one surface of the annular frame 19 become the same plane.

[0053] Above the support table, a tape body (not shown) is provided. In addition, a roller-shaped pressing member (not shown) that presses the dicing tape 17 sent out from the tape body toward the workpiece 11 is arranged near the tape body. The pressing member is configured to be able to move in a specified direction while rotating.

[0054] In addition, a cutter (not shown) that cuts the dicing tape 17 pasted on the workpiece 11 and the annular frame 19 into a circular shape is provided near the tape body. The cutter cuts the dicing tape 17 into a circular shape in such a manner that the diameter of the dicing tape 17 becomes a specified diameter that is larger than the inner diameter of the opening of the annular frame 19 and smaller than the outer diameter of the annular frame 19.

[0055] In the pasting step (S10), first, the workpiece 11 and the annular frame 19 are placed on the upper part of the support table with the front surface 11a of the workpiece 11 and one surface of the annular frame 19 facing upward.

[0056] And, the dicing tape 17 is arranged between the pressing member and the front surface 11a of the workpiece 11, and in a state where the front surface 11a side is pressed by the pressing member, the pressing member is moved while rotating along the X-axis direction.

[0057] Then, using the cutter, the dicing tape 17 is cut into a circular shape in such a manner that the dicing tape 17 becomes the above-mentioned specified diameter. Thus, a workpiece unit 21 in which the workpiece 11 and the annular frame 19 are integrated by the dicing tape 17 is formed.

[0058] After the pasting step (S10), a shield tunnel is formed in the workpiece 11 using a laser processing device 2 (shield tunnel forming step (S20)). Figure 3 (A) is a partial cross-sectional side view of the workpiece 11 etc. when the processing head 12a and the chuck table 10 are relatively moved, Figure 3 (B) is a partial cross-sectional side view of the workpiece 11 etc. after the processing head 12a and the chuck table 10 are relatively moved.

[0059] In the shield tunnel forming step (S20), first, the workpiece unit 21 is placed on the holding surface 10a with the front surface 11a of the workpiece 11 facing downward. In this state, the suction source is actuated to apply a negative pressure to the holding surface 10a. In addition, the annular frame 19 is fixed by the clamp unit. Thus, the front surface 11a side of the workpiece 11 is held by the chuck table 10 with the dicing tape 17 interposed therebetween.

[0060] Next, the orientation of the chuck table 10 is adjusted so that the dicing line 13 of the workpiece 11 is parallel to the X-axis direction. And the position of the chuck table 10 is adjusted so that the lower end of the processing head 12a is located on one end side in the X-axis direction (for example, the end side in the +X direction) of one dicing line 13 (refer to Figure 3 (A) of the figure).

[0061] Then, a pulsed laser beam L having a wavelength that is transmissive to the workpiece 11 is irradiated from the processing head 12a to the back surface 11b of the workpiece 11. At this time, the condensing region of the laser beam L is positioned inside the workpiece 11.

[0062] In a state where the condensing region of the laser beam L irradiated from the back surface 11b side of the workpiece 11 is positioned inside the workpiece 11, the X-axis moving unit 26 is actuated to move the chuck table 10 in the X-axis direction.

[0063] Thereby, the processing head 12a irradiates the laser beam L along the dicing line 13 while relatively moving with respect to the chuck table 10. In addition, in this specification, the relative moving speed of the processing head 12a and the chuck table 10 in the X-axis direction is referred to as the processing speed.

[0064] For example, the following processing conditions are set to process the workpiece 11.

[0065] Wavelength of the laser beam L: 1064 nm

[0066] Pulse energy: 50 μJ

[0067] Repetition frequency of the pulse: 1 kHz

[0068] Processing speed in the X-axis direction: 20 mm / s

[0069] Number of passes: 1

[0070] In addition, the pulse energy means the energy per 1 pulse. In addition, the number of passes means the number of times the laser beam L is irradiated along one dicing line 13 in a state where the condensing region is positioned inside the workpiece 11.

[0071] After moving the chuck table 10 in the X-axis direction in such a manner that the laser beam L is irradiated from one end to the other end (e.g., the end in the -X direction) of the X-axis direction of a division predetermined line 13, the irradiation of the laser beam L is temporarily stopped (see Figure 3 of (B)).

[0072] Next, the chuck table 10 is index-fed in the Y-axis direction by a predetermined indexing amount, and the lower end of the processing head 12a is positioned on another division predetermined line 13 adjacent to the previously processed division predetermined line 13 in the Y-axis direction.

[0073] Next, after moving the chuck table 10 in the X-axis direction in such a manner that the laser beam L is irradiated from the other end (e.g., the end in the -X direction) to one end (e.g., the end in the +X direction) of the X-axis direction of the other division predetermined line 13, the irradiation of the laser beam L is temporarily stopped again (see Figure 3 of (B)).

[0074] In this way, the laser beam L is irradiated along all the division predetermined lines 13 parallel to one direction. Then, the chuck table 10 is rotated by 90 degrees and the laser beam L is irradiated along all the division predetermined lines 13 parallel to the other direction perpendicular to one direction. Thereby, a plurality of shield tunnels 11d are respectively formed along all the division predetermined lines 13.

[0075] In addition, when the processing speed in the X-axis direction exceeds 50 mm / s, it is difficult to form a shield tunnel along the division predetermined line 13. Considering various reasons, for example, sometimes the shield tunnel is formed meanderingly with respect to the division predetermined line 13. Therefore, it is more preferable that the processing speed in the X-Y plane direction is 50 mm / s or less.

[0076] Figure 4 (A) of Figure 4 is a perspective view showing the structure of one shield tunnel 11d. In addition, in

[0077] (A) of

[0078] The deteriorated region 11f is a region where a part of the workpiece 11 receives energy from the laser beam L, causing changes in structure, density, etc. compared to the part not irradiated with the laser beam L. For example, when the workpiece 11 is formed of a single crystal material such as silicon, the deteriorated region 11f becomes an amorphous region or a polycrystalline region.

[0079] Figure 4 (B) thereof is a cross-sectional view showing a part of the workpiece 11 of a plurality of shield tunnels 11d formed along a single dividing predetermined line 13. In Figure 4 (B) thereof, the side portions of the deteriorated regions 11f of two shield tunnels 11d adjacent along the dividing predetermined line 13 are connected, but the side portions of the two deteriorated regions 11f may be separated from each other along the dividing predetermined line 13. Further, in Figure 4 (B) thereof, a part in the thickness direction of the workpiece 11 is omitted.

[0080] After the shield tunnel forming step (S20), an ultrasonic wave is applied to the workpiece 11 via a liquid 40 such as water (e.g., pure water) and the scribe tape 17 is expanded using the ultrasonic wave applying device 38, thereby breaking the shield tunnel 11d and dividing the workpiece 11 (dividing step (S30)). Figure 5 (A) thereof is a partially cut-away side view of the ultrasonic wave applying device 38 and the like.

[0081] The ultrasonic wave applying device 38 has a container 42. In the container 42, the liquid 40 is filled to a specified height position. A plurality of legs 44 that can expand and contract in the height direction of the container 42 are arranged inside the container 42, and the bottom of the legs 44 is fixed to the bottom inside the container 42. Further, in Figure 5 (A) thereof, each leg 44 in the state of being maximally extended is shown.

[0082] A ring-shaped support portion 44a is fixed to the upper end of each leg 44. The ring-shaped frame 19 of the above-described workpiece unit 21 is placed on the upper surface of the support portion 44a. A plurality of clamp units 46 are provided on the outer peripheral side surface of the support portion 44a.

[0083] Each clamp unit 46 is discretely arranged at different positions in the circumferential direction of the support portion 44a. For example, when looking down on the support portion 44a, four clamp units 46 are provided at the 0 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions of a clock.

[0084] A jacking device 48 that jacks up the scribe tape 17 of the workpiece unit 21 from below is provided at a position closer to the inside than the plurality of legs 44. The jacking device 48 has a plurality of legs 48a that can expand and contract in the height direction of the container 42, and the bottom of the legs 48a is fixed to the bottom inside the container 42. Further, in Figure 5In (A), each leg 48a is shown in a state positioned at the same height as the leg 44.

[0085] At the upper end of each leg 48a, a ring-shaped lifting member 48b is provided. A part of the base material layer of the dicing tape 17 between the outer peripheral end of the workpiece 11 and the inner diameter of the ring-shaped frame 19 is in contact with the upper surface of the lifting member 48b.

[0086] An ultrasonic generating unit 50 is fixed to the bottom inside the container 42. The ultrasonic generating unit 50 has, for example, a piezoelectric element (not shown) formed using a piezoelectric material such as lead zirconate titanate (PZT).

[0087] By applying a prescribed alternating voltage to the piezoelectric element, the piezoelectric element vibrates. Thereby, the ultrasonic generating unit 50 generates ultrasonic waves having a prescribed frequency exceeding 20 kHz (for example, a frequency in the range of 20 kHz to 100 kHz).

[0088] In the dividing step (S30), first, as shown in (A) of Figure 5 , the workpiece unit 21 is placed on the support portion 44a. And the upper part of the ring-shaped frame 19 is held by each clamp unit 46. Thus, the workpiece unit 21 is fixed by the clamp unit 46 and the support portion 44a.

[0089] Then, the legs 44 and 48a are contracted to the same prescribed length so that the workpiece 11 is positioned lower than the water level of the liquid 40 and higher than the ultrasonic generating unit 50. Thereby, the entire workpiece unit 21 is immersed in the liquid 40. By maintaining the legs 44 at a prescribed length, the distance between the front surface 11a (or the back surface 11b) and the ultrasonic generating unit 50 can be made constant.

[0090] In addition, the height position of the workpiece 11 can be adjusted to a prescribed position where ultrasonic waves are easily transmitted. For example, when the wavelength of the standing wave of the ultrasonic waves generated in the liquid 40 is λ, the workpiece 11 can be positioned at a position of {(2n - 1)λ} / 4 from the upper end of the ultrasonic generating unit 50 (where n is a natural number of 1 or more).

[0091] After positioning the workpiece 11 at an appropriate height position, a prescribed alternating voltage is applied to the ultrasonic generating unit 50 to generate ultrasonic waves. The ultrasonic waves propagate in the liquid 40 in the form of compression waves (i.e., longitudinal waves). Figure 5 (B) is a view showing the case where ultrasonic waves are applied to the workpiece 11 via the liquid 40.

[0092] Next, the dicing tape 17 is expanded. Figure 5Figure (C) shows a state in which the dicing tape 17 is expanded while applying ultrasonic waves to the workpiece 11 via the liquid 40. In a state where the length of the leg portion 44 is maintained, the lifting member 48b of the lifting device 48 is positioned at a predetermined position higher than the support portion 44a.

[0093] The upper end of the leg portion 48a slowly rises to a predetermined position over a predetermined time (for example, several seconds to several tens of seconds), but it may also instantaneously rise to the predetermined position. By raising the upper end of the leg portion 48a to the predetermined position, the dicing tape 17 is expanded in the radial direction. As a result, the workpiece 11 is subjected to a tensile stress in the radial direction.

[0094] The radial tensile stress applied to the workpiece 11 is, for example, proportional to the amount of rise of the upper end of the leg portion 48a relative to the leg portion 44. In the present embodiment, since ultrasonic waves are applied via the liquid 40, even if the amount of rise of the leg portion 48a is reduced compared to the case where the workpiece 11 is divided by applying only a tensile stress without applying ultrasonic waves via the liquid 40, the workpiece 11 can be divided along the plurality of division lines 13.

[0095] That is, even if the tensile stress applied to the workpiece 11 is reduced, the workpiece 11 can be divided. Therefore, compared with the case where the workpiece 11 is divided by applying only a tensile stress to the workpiece 11, the possibility of processing defects can be reduced.

[0096] In addition, by providing the liquid 40 between the workpiece 11 and the ultrasonic generating unit 50, the acoustic impedance when ultrasonic waves are transmitted to the workpiece 11 can be reduced compared to the case where only air or other gases exist between the workpiece 11 and the ultrasonic generating unit 50. That is, the liquid 40 functions as an acoustic matching layer that improves the propagation efficiency of ultrasonic waves compared to air.

[0097] In addition, since the liquid 40 enters the fine holes 11e, ultrasonic waves can also propagate into the fine holes 11e. Therefore, compared with the case where ultrasonic waves are applied to the workpiece 11 in a state where the liquid 40 does not exist in the fine holes 11e (for example, a state where the workpiece 11 is exposed to the atmospheric pressure environment), the deteriorated region 11f can be destroyed more efficiently.

[0098] In addition, when the upper end of the leg portion 48a is slowly raised to the predetermined position, the liquid 40 also enters the cracks in the deteriorated region 11f that is being destroyed by the tensile stress. Therefore, ultrasonic waves can also propagate into the cracks in the deteriorated region 11f. Therefore, compared with the case of instantaneously rising to the predetermined position, the possibility of processing defects can be further reduced.

[0099] In addition, chips and the like generated during the division of the workpiece 11 are spread in the liquid 40 by ultrasonic vibration and are not easily attached to the back surface 11b of the workpiece 11. Therefore, it is possible to prevent chips and the like from adhering to the front surface of the chip 23.

[0100] In addition, water is used as the liquid 40 instead of chemicals, chemical solutions, etc., so that the drainage treatment becomes easier compared to the etching treatment. In addition, it is also advantageous in that there is no need to perform a treatment for imparting chemical resistance such as acid resistance to the container 42, the legs 44, the support portion 44a, and the lifting device 48.

[0101] After the division step (S30), a plurality of chips 23 divided from the workpiece 11 are picked up (picking step (S40)). In the picking step (S40), in order to reduce the adhesive force of the adhesive layer of the dicing tape 17, a UV irradiation device (not shown) that irradiates the dicing tape 17 with ultraviolet rays is used. In addition, in order to convey the chip 23, a conveying device (not shown) disposed above the ultrasonic application device 38 is used.

[0102] The conveying device has an arm portion (not shown) that can move in the X-axis (or Y-axis) direction and the Z-axis direction. The upper surface of a disk-shaped head (not shown) is fixed to the lower end of the arm portion, and a plurality of adsorption pads (not shown) are provided on the lower surface of the head. Each adsorption pad is disposed at a position corresponding to the position of the chip 23.

[0103] Each adsorption pad has a flow path (not shown) connected to a suction source such as an ejector (not shown). One end (i.e., the opening) of this flow path is exposed below the adsorption pad. By the negative pressure generated by the suction source, an attractive force is generated at the opening of the adsorption pad.

[0104] In the picking step (S40), first, in a state where the holding lifting member 48b is present at a specified position higher than the support portion 44a (refer to (C) of Figure 5 ), the legs 44 and the leg 48a are extended.

[0105] At this time, the back surface of the dicing tape 17 is positioned above the water surface of the liquid 40. Thereby, a plurality of chips 23 are positioned above the water level of the liquid 40. Then, a UV irradiation device is disposed in the space between the back surface side of the dicing tape 17 and the water surface of the liquid 40, and the dicing tape 17 is irradiated with ultraviolet rays. As a result, the adhesive force of the adhesive layer is reduced.

[0106] Next, the arm portion of the conveying device is moved in the X-axis direction and positioned directly above the workpiece 11. Then, the arm portion is moved in the Z-axis direction so that the adsorption pad contacts the chip 23, and then the suction source is operated to adsorb the chip 23 with the adsorption pad.

[0107] Next, the arm is moved in the Z-axis direction to peel the chip 23 from the dicing tape 17, and then moved in the X-axis direction to transfer each chip 23 to a storage tray (not shown) for storing the chips 23.

[0108] In addition, in order to irradiate ultraviolet rays, the ultraviolet irradiation device may not be disposed between the bottom of the workpiece unit 21 and the water level of the liquid 40. For example, after the leg portion 44 is extended and the workpiece unit 21 is positioned above the water level of the liquid 40, the clamp unit 46 is released, and the workpiece unit 21 is transferred to another ultraviolet irradiation device (not shown). Then, the dicing tape 17 is irradiated with ultraviolet rays using the other ultraviolet irradiation device. Then, each chip 23 is transferred to the storage tray using a transfer device (not shown).

[0109] Next, the second embodiment will be described. In the dicing step (S30) of the second embodiment, after ultrasonic waves are applied to the workpiece 11 via the liquid 40, the workpiece 11 is taken out of the liquid 40, and then the dicing tape 17 is expanded to dice the workpiece 11. This is different from the first embodiment.

[0110] In the dicing step (S30) of the second embodiment, first, an ultrasonic wave applying device 52 having the same container 42, leg portion 44, support portion 44a, and ultrasonic wave generating unit 50 as those in the first embodiment is used to apply ultrasonic waves to the workpiece 11 (ultrasonic wave application step). In addition, in the container 42, the liquid 40 is filled to a predetermined depth position.

[0111] Figure 7 FIG. (A) is a partial cross-sectional side view of the ultrasonic wave applying device 52 and the like. In the ultrasonic wave application step, first, the workpiece unit 21 is placed on the support portion 44a, and the upper part of the annular frame 19 is held by each clamp unit 46.

[0112] Then, the leg portion 44 is contracted so that the workpiece 11 is positioned lower than the water level of the liquid 40 and higher than the ultrasonic wave generating unit 50, and the entire workpiece unit 21 is immersed in the liquid 40.

[0113] And, ultrasonic waves are generated by the ultrasonic wave generating unit 50, and ultrasonic waves are applied to the workpiece 11 via the liquid 40. After ultrasonic waves are applied to the workpiece 11 via the liquid 40, the leg portion 44 is extended to position the workpiece 11 above the water level of the liquid 40, and the clamp unit 46 is released.

[0114] Next, the dicing tape 17 is expanded using a dicing device 60 to dice the workpiece 11 (expansion step). Figure 7(B) is a partial cross-sectional side view of the dividing device 60 or the like.

[0115] In the dividing device 60, the leg portion 44 of the ultrasonic application device 52 corresponds to the leg portion 54 of the ultrasonic application device 38. Further, the support portion 44a corresponds to the support portion 54a, and the jig unit 46 corresponds to the jig unit 56. Further, the jacking device 58 corresponds to the jacking device 48.

[0116] In the expanding process, the workpiece 11 is moved from the ultrasonic application device 52 to the support portion 54a of the dividing device 60, and then the upper part of the annular frame 19 is held by each jig unit 46. And, with the height position of the leg portion 58a of the jacking device 58 fixed, the leg portion 54 is slowly contracted.

[0117] As a result, the jacking member 58b is positioned at a predetermined position higher than the support portion 54a, the dicing tape 17 is expanded in the radial direction, and the workpiece 11 is subjected to a tensile stress in the radial direction. Figure 7 (C) is a view showing a case where the dicing tape 17 is expanded using the dividing device 60.

[0118] In the second embodiment, the mechanical strength of the deteriorated region 11f also becomes weaker compared to before the application of ultrasonic waves. Therefore, even if the tensile stress is reduced, the workpiece 11 can be divided. Thus, compared with the case where the workpiece 11 is divided by applying only a tensile stress to the workpiece 11, the possibility of occurrence of processing defects can be reduced.

[0119] After the expanding process, a picking step (S40) is performed. In the picking step (S40), the above-described ultraviolet irradiation device (not shown) is disposed on the back side of the dicing tape 17, and the dicing tape 17 is irradiated with ultraviolet rays. As a result, the adhesive force of the adhesive layer is reduced. Then, each chip 23 is transported to a storage tray (not shown) using the above-described transport device (not shown).

[0120] In addition, the configurations, methods, etc. of the above-described embodiments can be appropriately changed and implemented as long as they do not depart from the scope of the object of the present invention.

Claims

1. A method for manufacturing a plurality of chips, the method comprising dividing a workpiece having a plurality of regions on a front side divided by a plurality of intersecting division predetermined lines along the plurality of division predetermined lines to manufacture a plurality of chips, characterized in that the method has the following steps: A pasting step of pasting an extensible tape on the workpiece and the annular frame, thereby forming a workpiece unit in which the workpiece is integrated with the annular frame by means of the tape in a state where the workpiece is disposed in the opening of the annular frame; A shield tunnel forming step of irradiating the laser beam along each division predetermined line from the back side of the workpiece in such a manner that the condensing region of the pulsed laser beam having a wavelength transmissive to the workpiece is positioned inside the workpiece, thereby forming a plurality of shield tunnels each having a fine hole and a metamorphic region surrounding the fine hole along each division predetermined line; and A dividing step, after the shield tunnel forming step, fixing the annular frame on a plurality of legs provided in a container, and then adjusting the height position of the workpiece unit by the expansion and contraction of the plurality of legs, thereby applying ultrasonic waves to the workpiece via the liquid in a state where the workpiece unit is positioned lower than the water level of the liquid filled to a predetermined height position from the bottom of the container, and expanding the tape by a jacking device that jacks up the tape from below, thereby dividing the workpiece along the plurality of division predetermined lines.

2. The method for manufacturing a plurality of chips according to claim 1, characterized in that in the dividing step, the tape is expanded while applying ultrasonic waves to the workpiece via the liquid, thereby dividing the workpiece along the plurality of division predetermined lines.

3. The method for manufacturing a plurality of chips according to claim 1 or 2, characterized in that performing the application of the ultrasonic waves in the dividing step includes the following steps: adjusting the height position of the workpiece unit by the plurality of legs, thereby adjusting the height position of the workpiece to a predetermined height position where ultrasonic waves are easily transmitted in the liquid.

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