JP2019062146A - Protective member processing method - Google Patents

Abstract

To provide a new protective member processing method capable of properly processing a resin protective member.SOLUTION: A protective member processing method for processing a protective member stuck to a wafer using a griding device including a chuck table having a holding surface for holding the wafer and a griding unit for rotating a grinding wheel including a plurality of annularly arranged grinding stones includes a protective member sticking step and a protective member processing step. The protective member sticking step sticks an adhesive material layer side of a protective member including a base material formed of a material containing a resin and an adhesive material layer provided on one surface of the base material to a surface of the wafer. The protective member processing step processes the protective member so that the thickness of the base material becomes thin by holding a rear surface side of the wafer on the holding surface and bringing grinding stones into contact with the other surface side of the base material of the protective member by rotating the grinding wheel. Each of the plurality of grinding stones is formed so that the angle formed by a front surface located on a front side in a rotational direction of the grinding wheel and a bottom surface becomes an acute angle.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method of processing a protective member for processing a protective member attached to a wafer.

  In an electronic device represented by a mobile phone or a personal computer, a device chip including a device such as an integrated circuit is an essential component. For example, the device chip divides the surface side of a wafer made of a semiconductor material such as silicon by a plurality of dividing lines (streets), forms a device in each area, and divides the wafer along the dividing lines. It is obtained by

  In recent years, there has been an increasing opportunity to thin wafers before division for the purpose of reducing the size and weight of device chips. For example, the wafer is ground from the back side by rotating a disk-shaped tool in which a plurality of grinding wheels formed by dispersing abrasive grains in a bonding material is fixed and the grinding wheels are brought into contact with the back side of the wafer. It can be thin.

  When grinding the back side of the wafer by the method as described above, a resin protective member called a protective tape is attached to the front side of the wafer, and the exposed side of the protective tape is held by a chuck table etc. There are many things to do. Thereby, it is possible to prevent the device formed on the surface of the wafer from being damaged by the load applied during grinding.

  By the way, the protection member made of resin is not necessarily formed in uniform thickness, and by simply sticking this protection member on the surface of the wafer, the thickness of the wafer after thinning by grinding tends to vary. Therefore, prior to grinding the wafer, a technique has been proposed in which the exposed surface of the protective member is ground to process the exposed surface of the protective member approximately parallel and flat to the back surface of the wafer (for example, Patent Document) 1 and 2).

Japanese Patent Application Laid-Open No. 61-141142 JP, 2005-19666, A

  However, when the protective member made of resin is ground with the above-mentioned grinding wheel, the grinding wheel is easily clogged by debris generated during grinding (grind). If the grinding wheel is clogged, the processing load increases and the protective member can not be properly processed.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a new processing method of a protective member which can appropriately process a resin protective member.

  According to one aspect of the invention, there is provided a grinding apparatus comprising a chuck table having a holding surface for holding a wafer, and a grinding unit for rotating a grinding wheel having a plurality of annularly arranged grinding wheels. A method of processing a protective member for processing a protective member attached to the wafer, comprising: a base formed of a material containing a resin; and an adhesive layer provided on one side of the base A protective member attaching step of attaching the adhesive material layer side of the protective member to the front surface of the wafer; holding the back surface side of the wafer by the holding surface; rotating the grinding wheel; And a protective member processing step of processing the protective member so that the thickness of the substrate is reduced by bringing the grinding wheel into contact with the other surface side of the plurality of grinding wheels. Direction of rotation of grinding wheel The front surface located on the front side and the bottom surface are formed so as to form an acute angle, and in the protective member processing step, the chuck table and the grinding wheel are not rotated without rotating the chuck table. There is provided a method of processing a protective member characterized by relative movement in a direction perpendicular to the rotation axis of the grinding wheel.

  In the method of processing a protective member according to one aspect of the present invention, the grinding wheel is rotated without rotating the chuck table using a grinding wheel including a grinding wheel formed so that the angle between the front surface and the bottom surface is an acute angle. In this state, the chuck table and the grinding wheel are relatively moved in the direction perpendicular to the rotation axis of the grinding wheel, so that debris generated during grinding is properly discharged by the sharp corner of the grinding wheel, The grinding wheel is less likely to be clogged. Therefore, according to the processing method of the protection member concerning one mode of the present invention, the protection member made of resin can be processed appropriately.

FIG. 1 (A) is a perspective view schematically showing a configuration example of a wafer, and FIG. 1 (B) is a perspective view for explaining a protective member attaching process. It is a perspective view which shows typically the example of composition of the grinding device used at a protective member processing process. It is a perspective view which shows the structure of a grinding wheel typically. It is a partial cross section side view for demonstrating a protection member processing process.

  Embodiments according to one aspect of the present invention will be described with reference to the attached drawings. The processing method of a protection member concerning this embodiment includes a protection member pasting process (refer to Drawing 1 (B)), and a protection member processing process (refer to Drawing 4). In the protective member attaching step, a protective member made of a material such as resin is attached to the front side of the wafer. In the protective member processing step, the protective member attached to the wafer is processed and thinned. Hereinafter, the processing method of the protection member concerning this embodiment is explained in full detail.

  FIG. 1A is a perspective view schematically showing a configuration example of a wafer 11 used in the present embodiment. As shown in FIG. 1A, the wafer 11 is formed in a disk shape using a semiconductor material such as silicon (Si), for example. The surface 11 a side of the wafer 11 is divided into a plurality of areas by a plurality of dividing planned lines (streets) 13 crossing each other, and in each area, a device 15 such as an IC (Integrated Circuit) is formed.

  In the present embodiment, the disk-shaped wafer 11 made of a semiconductor material such as silicon is used, but the material, shape, structure, size, etc. of the wafer 11 are not limited. For example, a substrate made of a material such as ceramic, resin, metal or the like can be used as the wafer 11. Similarly, there is no limitation on the type, number, size, arrangement, etc. of the devices 15. Further, a substrate or the like on which the device 15 is not formed may be used as the wafer 11.

  In the method of processing a protective member according to the present embodiment, first, a protective member attaching step of attaching the protective member on the surface 11 a side of the above-described wafer 11 is performed. FIG. 1 (B) is a perspective view for explaining the protective member attaching process. The protective member 21 is formed, for example, in a circular shape having a diameter substantially equal to that of the wafer 11, and shows a film-like (flat plate) base 23 made of a material containing a resin and a predetermined adhesive force. And an adhesive layer 25 provided on one surface of the material 23.

  Therefore, as shown in FIG. 1B, the protective member 21 can be attached to the surface 11 a side of the wafer 11 by bringing the adhesive material layer 25 side of the protective member 21 into close contact with the surface 11 a side of the wafer 11. By attaching the protective member 21 to the front surface 11 a side of the wafer 11, the load, impact, and the like when grinding the rear surface 11 b side of the wafer 11 later are alleviated, and the device 15 formed on the front surface 11 a side of the wafer 11 Etc. can be protected.

  After the protective member attaching step, a protective member processing step of processing the protective member 21 attached to the wafer 11 is performed. FIG. 2 is a perspective view schematically showing a configuration example of the grinding apparatus 2 used in the protective member processing step. As shown in FIG. 2, the grinding device 2 includes a base 4 on which each component is mounted. The rear end of the base 4 is provided with a support structure 6 extending upward.

  In the upper surface of the base 4, an opening 4 a which is long in the X-axis direction (front-rear direction) is formed. A ball screw type X-axis moving mechanism 8 and a dustproof and drip-proof cover 10 covering a part of the X-axis moving mechanism 8 are disposed in the opening 4 a. The X-axis moving mechanism 8 includes an X-axis moving table 8a, and moves the X-axis moving table 8a in the X-axis direction. In front of the opening 4a, an operation panel 12 for inputting processing conditions and the like is installed.

  A chuck table 14 for holding the wafer 11 to which the protective member 21 is attached is provided on the X-axis moving table 8a. A part of the upper surface of the chuck table 14 is a holding surface 14 a for sucking and holding the wafer 11.

  The holding surface 14 a is generally flat and connected to a suction source (not shown) via a suction path (not shown) or the like formed inside the chuck table 14. The wafer 11 can be sucked and held by the chuck table 14 by placing the wafer 11 on the holding surface 14 a and applying a negative pressure of a suction source.

  The chuck table 14 moves in the X-axis direction together with the X-axis moving table 8 a by the above-described X-axis moving mechanism 8. In addition, the chuck table 14 may be connected to a rotational drive source (not shown) such as a motor. In this case, for example, the chuck table 14 can be rotated about a rotation axis substantially parallel to the Z-axis direction (vertical direction).

  A Z-axis moving mechanism 16 is provided on the front surface of the support structure 6. The Z-axis moving mechanism 16 includes a pair of Z-axis guide rails 18 generally parallel to the Z-axis direction. A Z-axis moving plate 20 is slidably attached to the Z-axis guide rails 18. A nut portion (not shown) is provided on the rear surface side (rear surface side) of the Z-axis moving plate 20, and a Z-axis ball screw 22 substantially parallel to the Z-axis guide rail 18 is screwed into this nut portion. ing.

  A Z-axis pulse motor 24 is connected to one end of the Z-axis ball screw 22. By rotating the Z-axis ball screw 22 by the Z-axis pulse motor 24, the Z-axis moving plate 20 moves in the Z-axis direction along the Z-axis guide rail 18. The front side (surface) of the Z-axis moving plate 20 is provided with a support 26 projecting forward.

  The support 26 supports a grinding unit (processing unit) 28 for processing the protection member 21 attached to the wafer 11. The grinding unit 28 includes a spindle housing 30 fixed to the support 26. A spindle 32 serving as a rotational shaft is accommodated in the spindle housing 30 in a rotatable state.

  The lower end (tip) of the spindle 32 is exposed to the outside of the spindle housing 30. At the lower end of the spindle 32, a disk-shaped wheel mount 34 is provided. On the lower surface of the wheel mount 34, a disc-like grinding wheel 36 having a diameter substantially the same as that of the wheel mount 34 is fixed by a bolt or the like.

  FIG. 3 is a perspective view schematically showing the structure of the grinding wheel 36. As shown in FIG. As shown in FIG. 3, the grinding wheel 36 according to this embodiment includes a disk-shaped (annular) wheel base 38 made of stainless steel, aluminum or the like. The wheel base 38 has an upper surface 38a and a lower surface 38b substantially parallel to each other, and a generally circular opening 38c penetrating the base 38 from the upper surface 38a to the lower surface 38b is formed at the center thereof. The lower surface 38b of the wheel base 38 is provided with a plurality of supply ports 38d for supplying a liquid (processing fluid) such as pure water downward.

  When the grinding wheel 36 is attached to the grinding apparatus 2 described above, the upper surface 38a of the wheel base 38 is in close contact with the lower surface of the wheel mount 34, and the wheel base 38 is fixed to the wheel mount 34 with a bolt or the like. That is, the upper surface 38 a of the wheel base 38 is a fixed end face in contact with the wheel mount 34 of the grinding device 2. On the other hand, the lower surface 38 b of the wheel base 38 is a free end surface not fixed to the grinding device 2.

  On the lower surface 38b of the wheel base 38, a plurality of grinding wheels 40 in which abrasive grains such as diamond or CBN (Cubic Boron Nitride) are dispersed in a bonding material such as resin or metal are annularly arranged and fixed. There are no particular restrictions on the type (material) of the bonding material that constitutes the grinding wheel 40, the material, size, shape, etc. of the abrasive grains, but in the present embodiment, the diamond abrasive grains are a bonding material of nickel (plating) Using the grinding wheel 40 fixed in FIG.

  As shown in FIG. 3, each grinding wheel 40 has a front surface 40 a located on the front side of a direction (rotation direction) A in which the grinding wheel 36 is rotated when processing the protective member 21 and a bottom surface 40 b located below. Are formed to be acute angles. Although there is no limitation on the value of the specific angle, for example, it may be 75 ° to 85 °, typically about 80 °. As a result, it is easy to improve the dischargeability of scraps (machining scraps) generated during processing while sufficiently maintaining the strength of the grinding wheel 40.

  Further, in the grinding wheel 40 of the present embodiment, the angle between the rear surface 40c located on the rear side in the direction A of rotating the grinding wheel 36 and the bottom surface 40b located below is also an acute angle. . Thus, even when the grinding wheel 36 is rotated in the direction opposite to the normal direction A, the protective member 21 can be appropriately processed. However, if the angle between the front surface 40a and the bottom surface 40b with respect to the normal direction A is an acute angle, the angle between the rear surface 40c and the bottom surface 40b may not be an acute angle.

  In the present embodiment, the grinding wheel 36 is rotated with the direction A shown in FIG. 3 as the normal direction. However, the grinding wheel 36 is configured to rotate with the direction opposite to the direction A as the normal direction. You may. In this case, the angle between the front surface (ie, the rear surface 40c of the present embodiment) located on the front side in the direction opposite to the direction A and the bottom surface (the bottom surface 40b of the present embodiment) located below is The grinding wheel may be formed to have an acute angle.

  FIG. 4 is a plan view for explaining the protective member processing step. In the protective member processing step, first, the back surface 11b side of the wafer 11 is brought into contact with the holding surface 14a of the chuck table 14 described above, and a negative pressure of a suction source is applied to the holding surface 14a. Thus, the wafer 11 is sucked and held by the chuck table 14 so that the base 23 of the protective member 21 attached on the surface 11 a side is exposed upward.

  After suction and holding the wafer 11 by the chuck table 14, the grinding wheel 36 is rotated in a predetermined direction at a predetermined rotation number. At the same time, the grinding wheel 36 is lowered so that the height of the bottom surface 40 b of the grinding wheel 40 is lower than the other surface (upper surface) of the base 23 of the protective member 21. On the other hand, the chuck table 14 is not rotated.

  Then, the chuck table 14 is moved in the X-axis direction (ie, the grinding wheel 36) so that the grinding stone 40 contacts the base material 23 of the protective member 21 while supplying the liquid (working fluid) from the plurality of supply ports 38d and the like. Move in the direction perpendicular to the rotation axis). The rotation speed of the grinding wheel 36 is, for example, about 4000 rpm, and the supply amount of liquid is, for example, about 3.0 L / min to 7.0 L / min, and the moving speed of the chuck table 14 in the X axis direction is For example, about 0.1 mm / s to 0.5 mm / s. However, processing conditions are not limited to these.

  Thus, as shown in FIG. 4, the other surface side of the base 23 of the protective member 21 can be processed and thinned by the grinding stone 40. For example, when the exposed surface of the base 23 of the protective member 21 is substantially parallel and flat with the back surface 11 b of the wafer 11, the protective member processing step is finished.

  As described above, the grinding wheel 40 of this embodiment is formed such that the angle between the front surface 40a located on the front side in the direction A of rotating the grinding wheel 36 and the bottom surface 40b located below is an acute angle. It is done. Therefore, the discharge property of the wastes (machining wastes) generated at the time of processing of protection member 21 becomes high, and it becomes difficult to clog grinding stone 40.

  Further, in the present embodiment, the chuck table 14 and the grinding wheel 36 are relatively moved in the direction perpendicular to the rotation axis of the grinding wheel 36. As a result, the corner formed by the front surface 40a and the bottom surface 40b of the grinding stone 40 is caused to cut into the base 23 of the protective member 21 and the protective member 21 (base 23) is efficiently (effective ) Can be processed.

  After the protective member processing step, for example, a grinding step of grinding the back surface 11 b side of the wafer 11 may be performed. In this case, the wafer 11 can be ground using the grinding device 2 and the grinding wheel 36 described above, or the wafer 11 may be ground using another grinding device or grinding wheel.

  In the processing method of the protection member according to the present embodiment, since the protection member 21 can be appropriately processed, the thickness variation is caused by holding the protection member 21 side with a chuck table or the like and grinding the back surface 11b side of the wafer 11. Can be made thinner while suppressing the That is, the processing accuracy of the wafer 11 can be enhanced by incorporating the processing method of the protective member according to the present embodiment into the processing method (grinding method) of the wafer.

  As described above, in the processing method of the protective member according to the present embodiment, the chuck table 14 is formed using the grinding wheel 36 including the grinding stone 40 formed so that the angle between the front surface 40a and the bottom surface 40b is acute. Since the chuck table 14 and the grinding wheel 36 are relatively moved in the direction perpendicular to the rotation axis of the grinding wheel 36 in a state where the grinding wheel 36 is rotated without being rotated, scraps generated during grinding are ground The sharp corners of the grinding wheel 40 properly discharge the grinding wheel 40 so that clogging is less likely. Therefore, according to the processing method of the protection member concerning this embodiment, protection member 21 made of resin can be processed appropriately.

  The present invention is not limited to the description of the above embodiment, and can be implemented with various modifications. For example, although the grinding wheel 40 in which the abrasive grains of diamond are fixed by the bonding material of nickel is used in the above embodiment, a cemented carbide blade made of metal carbide or the like may be used as the grinding wheel 40. That is, abrasive grains need not necessarily be dispersed in the grinding wheel 40.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

11 wafer 11a front surface 11b back surface 13 division lines (street)
15 device 21 protection member 23 base material 25 adhesive layer 2 grinding device 4 base 6 support structure 8 X axis movement mechanism 8a X axis movement table 10 dustproof drip-proof cover 12 operation panel 14 chuck table 14a holding surface 16 Z axis movement mechanism 18 Z axis guide rail 20 Z axis moving plate 22 Z axis ball screw 24 Z axis pulse motor 26 Support 28 Grinding unit (processing unit)
Reference Signs List 30 spindle housing 32 spindle 34 wheel mount 36 grinding wheel 38 wheel base 38a upper surface 38b lower surface 38c opening 38d supply port 40 grinding wheel 40a front surface 40b bottom surface 40c rear surface A direction

Claims (1)

A protection member attached to a wafer using a grinding apparatus comprising: a chuck table having a holding surface for holding a wafer; and a grinding unit for rotating a grinding wheel having a plurality of annularly arranged grinding wheels It is a processing method of the protection member to process,
Protective member attaching process for attaching the adhesive layer side of a protective member having a base formed of a material containing a resin and an adhesive layer provided on one side of the base to the surface of the wafer When,
The thickness of the substrate is reduced by holding the back surface side of the wafer with the holding surface and rotating the grinding wheel to bring the grinding wheel into contact with the other surface side of the substrate of the protective member. A protective member processing step of processing the protective member to be
The plurality of grinding wheels are formed such that the angle between the front surface and the bottom surface located on the front side in the direction in which the grinding wheel rotates is acute.
In the protective member processing step, the protective member is characterized in that the chuck table and the grinding wheel are relatively moved in the direction perpendicular to the rotation axis of the grinding wheel without rotating the chuck table. Processing method.