Protective tape peeling method

Abstract

To provide a method for separating a protective tape without fail that can surely separate the protective tape from a surface of a wafer.SOLUTION: The method includes: a thermal compression bonding step of putting a separation tape on an outer periphery of a protective tape to press a heat bar, and thermally compressing and bonding the separation tape to the outer periphery of the protective tape; and a protective tape separation step of pulling the separation tape off to separate the protective tape from a surface of a wafer. In the thermal compression bonding step, the heat bar is pressed against the separation tape at a plurality of positions and the separation tape is thermally compressed and bound to the protective tape.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a protective tape peeling method for peeling off a protective tape attached to the surface of a wafer. [Background technology]

[0002] A wafer, on whose surface a number of devices such as ICs and LSIs are formed and partitioned along planned dividing lines, has a protective tape attached to its surface, and the back surface is ground by a grinding device to form the wafer into the desired thickness. The wafer is then divided into individual device chips by a dicing device and laser processing device for use in electrical devices such as mobile phones and personal computers.

[0003] In addition, after grinding the back surface of the wafer, a peeling tape is thermocompression-bonded to the protective tape attached to the front surface of the wafer, and the protective tape is peeled off from the front surface of the wafer using the thermocompression-bonded peeling tape (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-16862 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the protective tape is a hard tape such as polyethylene terephthalate (PET) or when the thermocompression bonding force of the peeling tape to the protective tape is insufficient, there is a problem that the peeling tape peels off from the protective tape and the protective tape cannot be reliably peeled off from the surface of the wafer.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and a main technical object of the present invention is to provide a protective tape peeling method capable of reliably peeling the protective tape from the surface of a wafer. [Means for solving the problem]

[0007] In order to solve the above-mentioned main technical problem, according to the present invention, there is provided a protective tape peeling method for peeling off a protective tape applied to a surface of a wafer, the method comprising: a thermocompression bonding step of laying a peeling tape on an outer periphery of the protective tape and pressing a heat bar to thermocompress the peeling tape to the outer periphery of the protective tape; and a protective tape peeling step of pulling the peeling tape to peel off the protective tape from the surface of the wafer, wherein in the thermocompression bonding step: Identical Heat bar , in multiple installments The peeling tape different A protective tape peeling method is provided in which the peeling tape is positioned at a plurality of locations and pressed to thermocompress the protective tape.

[0008] The present invention is suitable when the protective tape is made of polyethylene terephthalate. It is also preferable that the plurality of thermocompression bonded portions formed by the thermocompression bonding step are spaced apart from one another along the peeling direction. Effect of the Invention

[0009] The protective tape peeling method of the present invention includes a thermocompression step of laying a peeling tape on the outer periphery of the protective tape and pressing a heat bar to thermocompress the peeling tape to the outer periphery of the protective tape, and a protective tape peeling step of pulling the peeling tape to peel the protective tape from the surface of the wafer.In the thermocompression step, the heat bar is positioned at multiple points on the peeling tape and pressed to thermocompress the peeling tape to the protective tape, so that the protective tape can be reliably peeled off using the peeling tape. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing a mode of attaching a protective tape to a wafer. [Diagram 2] FIG. 2 is an overall perspective view of a grinding apparatus that performs a grinding step of grinding the back surface of a wafer. [Diagram 3] FIG. 2 is a partially enlarged perspective view showing an embodiment of a grinding step. [Figure 4]FIG. 2 is a perspective view showing a manner in which a wafer is placed on the protective tape peeling apparatus. [Diagram 5] FIG. 1A is a perspective view showing an embodiment of a thermocompression bonding step, FIG. 1B is a side view showing the thermocompression bonding step shown in FIG. 1A, and FIG. 1C is a perspective view showing an embodiment of a peeling tape thermocompression bonded by the thermocompression bonding step. [Figure 6] FIG. 11 is a perspective view showing an embodiment of a protective tape peeling step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a protective tape peeling method according to the present invention will be described with reference to the accompanying drawings.

[0012] 1 shows a wafer 10 as a workpiece to which the protective tape peeling method of the present embodiment is applied. The wafer 10 has a surface 10a on which a plurality of devices 12 are formed and partitioned by planned division lines 14, and a protective tape T is attached to the surface 10a. The protective tape T is, for example, a resin tape made of polyethylene terephthalate (PET), and is thermocompression bonded to the surface 10a of the wafer 10.

[0013] 2 shows an overall perspective view of a grinding apparatus 1 for grinding a wafer 10 according to this embodiment. The grinding apparatus 1 at least includes a holding means 3 disposed in an apparatus housing 2, a grinding means 4 for grinding a back surface 10b of the wafer 10 held by the holding means 3, and a lifting means 5 for lifting and lowering the grinding means 4 in the Z-axis direction (up and down direction).

[0014] The holding means 3 includes a chuck table 31 having a holding surface 31a that is defined by an X-axis direction and a Y-axis direction perpendicular to the X-axis direction and that constitutes a substantially horizontal plane. The chuck table 31 is configured to be rotatable by a rotary drive means (not shown). The holding surface 31a is made of a breathable material and is connected to a suction means (not shown). By operating the suction means, a suction negative pressure is supplied to the holding surface 31a. The chuck table 31 is moved by an X-axis moving means (not shown) housed inside the device housing 3 to any position in the X-axis direction, for example, a carry-in / out position at the front side in the figure where the wafer 10 is carried in and out, and a grinding processing position where grinding processing is performed directly below the grinding means 4.

[0015] The grinding means 4 includes at least a rotating shaft 41, a grinding wheel 42 disposed at the lower end of the rotating shaft 41, a plurality of grinding stones 43 disposed in an annular shape on the lower surface of the grinding wheel 42, an electric motor 44 for rotating the rotating shaft 41, a support part 45 for supporting the grinding means 4, and a Z-axis moving base 46 supported on the vertical wall part 2a of the device housing 2 so as to be movable up and down in the Z-axis direction together with the support part 45. The lifting means 5 converts the rotational motion of the pulse motor 51 into linear motion via a ball screw 52 rotated by the pulse motor 51 and transmits it to the Z-axis moving base 46, so that the grinding means 4 can be moved to any position in the Z-axis direction (up and down direction). The grinding device 1 includes a control means (not shown), and its operation is controlled by a control signal issued by the control means.

[0016] The grinding process carried out by the grinding device 1 will be described in more detail with reference to FIGS.

[0017] As shown in Fig. 2, the wafer 10 is placed on the holding surface 31a of the chuck table 31 positioned at the carry-in / out position with the protective tape T side facing downward and the back surface 10b side exposed upward, and the suction means is operated to hold the wafer by suction. Next, the X-axis moving means is operated to move the chuck table 31 in the X-axis direction and position the wafer at the grinding position directly below the grinding means 4. Then, the rotation drive means (not shown) is operated to rotate the chuck table 31 in the direction indicated by the arrow R1 at a predetermined rotation speed (e.g., 300 rpm) as shown in Fig. 3, and rotate the rotation shaft 41 of the grinding means 4 in the direction indicated by the arrow R2 at a predetermined rotation speed (e.g., 6000 rpm). Next, the above-mentioned lifting means 5 is operated to lower the grinding means 4 in the direction indicated by the arrow R3, the grinding wheel 43 is brought into contact with the back surface 10b of the wafer 10, and the wafer 10 is ground and thinned to a predetermined thickness while being fed for grinding at a predetermined speed (e.g., 1 μm / sec). Note that when carrying out this grinding process, the above-mentioned grinding process can be carried out while measuring the thickness of the wafer 10 by operating a thickness measuring means (not shown).

[0018] After the above-mentioned grinding process is performed, the above-mentioned lifting means 5 is operated to raise the grinding means 4, and the electric motor 44 is stopped. Next, the suction means supplying a negative suction pressure to the holding surface 31a of the chuck table 31 is stopped, and the wafer 10 is removed from the chuck table 31. Before removing the wafer 10 from the chuck table 31, it is preferable to operate a cleaning means (not shown) to clean and dry the back surface 10b side of the wafer 10. After the wafer 10 is removed from the chuck table 31, a protective tape peeling method is performed to peel off the protective tape T attached to the front surface 10a of the wafer 10.

[0019] When carrying out the protective tape peeling method of this embodiment, first, the wafer 10 carried out from the grinding device 1 is transported to a protective tape peeling device 7 (only a part of which is shown) shown in FIG. 4. The protective tape peeling device 7 includes a holding means 72 as shown in the figure. The holding means 72 includes a chuck table 74 having a holding surface 74a that is defined by an X-axis direction and a Y-axis direction perpendicular to the X-axis direction and that constitutes a substantially horizontal plane. The chuck table 74 is configured to be rotatable by a rotation drive means (not shown). The holding surface 74a is made of a member having air permeability and is connected to a suction means (not shown), and a suction negative pressure is supplied to the holding surface 74a by operating the suction means. The chuck table 74 is configured to be movable in the X-axis direction by an X-axis moving means (not shown).

[0020] When the wafer 10 is transported to the chuck table 74 of the protective tape peeling device 7, a thermocompression bonding process is performed. When performing the thermocompression bonding process, first, as shown in FIG. 4, the wafer 10 is placed on the chuck table 74 with the back surface 10b facing downward and the protective tape T facing upward. Next, a suction means (not shown) is operated to suck and hold the wafer 10 on the holding surface 74a of the chuck table 74. Here, as shown in FIG. 4, a peeling tape 6 is laid at a predetermined position 10c (indicated by a two-dot chain line) on the outer periphery of the protective tape T. The peeling tape 6 of this embodiment is a thermocompression tape that exerts adhesive force by heating, and is preferably selected from, for example, polyolefin-based or polyester-based resin tapes. When a polyolefin-based resin tape is adopted, it is preferably selected from any one of polyethylene, polypropylene, and polystyrene. When a polyester-based tape is adopted, it is preferably selected from any one of polyethylene terephthalate and polyethylene naphthalate. In this embodiment, the following description will be given assuming that a polyethylene tape is adopted as the peeling tape 6.

[0021] As described above, when the peeling tape 6 is laid at the tape application position 10c on the outer circumference of the protective tape T, the chuck table 74 is rotated in the direction indicated by R4 as shown in FIG. 5(a), and the position of the chuck table 74 in the X-axis direction is adjusted by operating the X-axis moving means (not shown), so that the heat bar 78 of the heating means 76 arranged in the protective tape peeling device 7 is positioned on the application part 62 of the peeling tape 6 laid at the tape application position 10c. The heat bar 78 is, for example, formed in a flat plate shape with a width corresponding to the width of the peeling tape 6, and the cross section of the tip part 78a of the heat bar 78 is formed so that the tip part 78a is pointed downward and convex. The heat bar 78 is formed of a metal with excellent thermal conductivity, and is connected to a heater (not shown) so that the temperature of the tip part 78a can be adjusted to a predetermined temperature.

[0022] As described above, once the heat bar 78 is positioned on the adhesion portion 62, the heating means 76 is operated to heat the tip 78a of the heat bar 78 to 120°C to 140°C. This temperature is close to the melting temperature of the peeling tape 6 made of polyethylene, and is the temperature at which the peeling tape 6 softens and becomes adhesive. If a thermocompression tape made of another material is selected as the peeling tape 6, the temperature is adjusted to a temperature at which the tape softens and becomes adhesive depending on the selected material.

[0023] Next, as shown in FIG. 5(b), the heat bar 78 is lowered in the direction indicated by the arrow R5 by a lifting means (not shown) and pressed against the affixing portion 62 of the peeling tape 6, so that the peeling tape 6 is thermocompressed to the protective tape T, forming a thermocompression-bonded portion 64a. As can be seen from FIG. 5(c), the thermocompression-bonded portion 64a is formed so as to extend in the width direction at the tip side of the affixing portion 62 of the peeling tape 6. After the thermocompression-bonded portion 64a is formed, the heat bar 78 is raised and the X-axis moving means of the chuck table 74 is operated to relatively move the heat bar 78 in the direction indicated by the arrow R6 as shown in FIG. 5(b), so that the heat bar 78 is positioned adjacent to the previously formed thermocompression-bonded portion 64a in the X-axis direction, and the heat bar 78 is pressed against the affixing portion 62 to form a thermocompression-bonded portion 64b. Similarly, a heat bar 78 is positioned and pressed at a position adjacent to the thermocompression bonded portion 64b in the X-axis direction to form the thermocompression bonded portion 64c. That is, as shown in Fig. 5(c), the heat bar 78 is positioned and pressed at multiple points on the peeling tape 6 to thermocompress the peeling tape 6 to the protective tape T. This completes the thermocompression bonding process.

[0024] After carrying out the above-mentioned thermocompression bonding process, as shown in FIG. 6, the protective tape T is peeled off from the front surface 10a of the wafer 10 by pulling the gripping portion 66 of the peeling tape 6 in the direction indicated by the arrow R7, thereby completing the protective tape peeling process.

[0025] According to the above-described embodiment, in the thermocompression bonding process, the heat bar 78 is positioned and pressed at multiple locations on the peeling tape 6, and the peeling tape 6 is thermocompressed to the protective tape T. Therefore, in the protective tape peeling process, the protective tape T can be reliably peeled off using the peeling tape 6.

[0026] In the above embodiment, the heat bar 78 is pressed against the peeling tape 6 three times to form three thermocompression bonded portions 64a-64c extending in a direction perpendicular to the X-axis direction, but the present invention is not limited to this and may have two or more. Also, in the above embodiment, the thermocompression bonded portions 64a-64c are formed as straight lines extending in a direction perpendicular to the X-axis direction, but they are not necessarily limited to being formed in a line shape and may be thermocompressed by pressing at multiple points, for example.

[0027] Furthermore, in the above-described embodiment, when the protective tape peeling method is carried out after the grinding process, the wafer is transported to the protective tape peeling device 7, and the thermocompression bonding process and the protective tape peeling process are carried out. However, the present invention is not limited to this. A heating means 76 may be provided in the grinding device 1 that carried out the grinding process, and the wafer 10 may be placed upside down on the chuck table 31 of the grinding device 1 with the protective tape T side facing upward and held by suction to carry out the above-described thermocompression bonding process and protective tape peeling process. [Explanation of symbols]

[0028] 1: Grinding method 2: Device housing 2a: Vertical wall 3: Holding means 31: Chuck table 31a: Holding surface 4: Grinding method 41: Rotation axis 42: Grinding wheel 43: Grinding wheel 44: Electric motor 45: Support part 46:Z-axis moving base 5: Lifting means 51: Pulse motor 52: Ball screw 6: Peeling tape 62: Adhesive part 64a~64c: Heat compression bonding part 66:Gripping part 7: Protective tape peeling device 72: Holding means 74: Chuck table 74a: Holding surface 76: Heating means 78: Heat Bar 78a:Tip 10: Wafer 10a: surface 10b: Back side 12: Device 14: Planned division line T: Protective tape

Claims

1. A protective tape peeling method for peeling off a protective tape attached to a surface of a wafer, comprising the steps of: a thermocompression bonding step of laying a peeling tape on the outer periphery of the protective tape and pressing the peeling tape with a heat bar to thermocompress the peeling tape onto the outer periphery of the protective tape; a protective tape peeling step of peeling the protective tape from the front surface of the wafer by pulling the peeling tape; Including, In the thermocompression bonding step, the same heat bar is positioned at a plurality of different positions on the peeling tape in a plurality of separate steps and pressed thereon to thermocompress the peeling tape to the protective tape.

2. 2. The method for peeling off a protective tape according to claim 1, wherein the protective tape is made of polyethylene terephthalate.

3. A protective tape peeling method as described in claim 1 or 2, wherein the multiple thermocompression bonded portions formed by the thermocompression bonding process are spaced apart along the peeling direction.

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