JP2019062147A - 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 grinding device including a chuck table having a holding surface for holding the wafer and a grinding unit for rotating a grinding wheel including a plurality of annularly arranged grinding stones includes a protective member sticking step, a groove forming 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 groove forming step forms a plurality of grooves having a depth not reaching the adhesive material layer on the other surface side of the base material. 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 a grinding stone into contact with the other surface side of the base material of the protective member by rotating the chuck table and the grinding wheel while supplying a liquid to the protective member.SELECTED DRAWING: Figure 7

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 a chuck table having a conical holding surface for holding a wafer, the chuck table rotating so that the apex of the conical shape is at the center of rotation; And a grinding unit for rotating a grinding wheel having a grinding wheel, wherein the protection member is attached to the wafer by using a grinding apparatus. And a pressure-sensitive adhesive layer provided on one surface of the substrate, wherein the pressure-sensitive adhesive layer side of the protective member is attached to the surface of the wafer; Forming a plurality of grooves on the other surface side of the base material, holding the back surface side of the wafer by the holding surface, rotating the chuck table and the grinding wheel respectively; The other side of the base of the protective member 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, and in the protective member processing step, a liquid is supplied to the protective member. A method of processing a protective member is provided, in which the protective member is processed by aligning the chuck table and the grinding wheel such that the grinding wheel passes through a position corresponding to the apex of the conical shape.

  In the groove forming step according to one aspect of the present invention described above, a plurality of grooves having a depth not reaching the adhesive layer can be obtained by cutting the rotated annular cutting blade into the base material of the protective member. You may form in the other surface side of this base material.

  Further, in the groove forming step according to one aspect of the present invention described above, by irradiating the base material with a laser beam, a plurality of grooves having a depth not reaching the adhesive layer can be the other side of the base You may form in.

  In the method for processing a protective member according to one aspect of the present invention, after forming a plurality of grooves on the other surface side of the base of the protective member, the grinding stone is brought into contact while supplying liquid to process the protective member. The protective member and the grinding wheel can be properly cooled by the liquid accumulated in the plurality of grooves, and the protective member can be processed while suppressing clogging of the grinding wheel. In addition, by forming a plurality of grooves in the substrate, the grinding wheel can be easily cut into the substrate, and the protective member can be processed efficiently. As described above, according to the method of processing a protective member according to one aspect of the present invention, a resin-made protective member can be appropriately processed.

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 partial cross section side view for demonstrating a groove formation 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 sectional drawing which shows the structure of a chuck table typically. It is a perspective view which shows the structure of a grinding wheel typically. It is a top view for demonstrating a protection member processing process. 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 method of processing a protective member according to the present embodiment includes a protective member attaching step (see FIG. 1B), a groove forming step (see FIG. 2), and a protective member processing step (see FIGS. 6 and 7). 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 groove forming step, a plurality of grooves are formed in the base material of the protective member. 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 groove forming step of forming a plurality of grooves on the other surface side (the opposite side of the adhesive material layer 25) of the base member 23 of the protective member 21 is performed. FIG. 2 is a partial cross-sectional side view for explaining the groove forming step. As shown in FIG. 2, the groove forming process according to the present embodiment is performed using the cutting device 1.

  The cutting apparatus 1 includes a chuck table 3 for sucking and holding the wafer 11 to which the protective member 21 is attached. The chuck table 3 is connected to a rotational drive source (not shown) such as a motor, and rotates around a rotational axis generally parallel to the vertical direction. Further, a processing feed mechanism (not shown) is provided below the chuck table 3, and the chuck table 3 is moved in the processing feed direction (first horizontal direction) by the processing feed mechanism.

  A part of the upper surface of the chuck table 3 is a holding surface 3 a that sucks and holds the back surface 11 b side of the wafer 11. The holding surface 3 a is connected to a suction source (not shown) via a suction path (not shown) or the like formed inside the chuck table 3. The wafer 11 is sucked and held by the chuck table 3 by applying a negative pressure of a suction source to the holding surface 3 a.

  A cutting unit 5 for cutting the protective member 21 is disposed above the chuck table 3. The cutting unit 5 includes a spindle 7 which is a rotation axis substantially parallel to the horizontal direction. An annular cutting blade 9 is mounted on one end side of the spindle 7. A rotational drive source (not shown) such as a motor is connected to the other end side of the spindle 7, and the cutting blade 9 mounted on the spindle 7 is rotated by the force transmitted from the rotational drive source.

  The cutting unit 5 is supported by a lift mechanism (not shown) and an indexing feed mechanism (not shown), moves (lifts) in the vertical direction by the lift mechanism, and an indexing feed direction perpendicular to the processing feed direction by the indexing feed mechanism. Move to (horizontal second direction).

  When forming a plurality of grooves in the protective member 21 using the cutting device 1, first, the back surface 11 b side of the wafer 11 is brought into contact with the holding surface 3 a of the chuck table 3 to apply negative pressure to the suction source. . Thereby, the back surface 11 b side of the wafer 11 is held by the chuck table 3, and the other surface side of the protective member 21 is exposed upward.

  Next, the chuck table 3 is rotated to make an arbitrary planned processing line set in the protective member 21 parallel to the processing feed direction of the cutting device 1. Furthermore, the chuck table 3 and the cutting unit 5 are moved relative to each other, and the cutting blade 9 is aligned with an extension of a desired processing line.

  Thereafter, the lower end of the rotated cutting blade 9 is lowered to a position lower than the other surface of the protective member 21 and higher than one surface, and the chuck table 3 is moved in the processing feed direction. Thereby, the cutting blade 9 can be cut into the other surface side of the base material 23, and the groove 23a along the target processing planned line can be formed.

  The above-described operation is repeated until grooves are formed along all planned processing lines set in the protective member 21. There are no particular limitations on the conditions such as depth, width, shape, and spacing (number) of the grooves 23a. For example, when the thickness of the base material 23 is about 30 μm to be reduced to about 10 μm, the depth is 5 μm to 15 μm. Linear grooves with a width of 0.1 mm to 0.3 mm, typically 0.2 mm, and a width of 0.5 mm to 2.0 mm, typically 1.0 mm. It is good to form.

  After the groove forming step, a protective member processing step of processing the protective member 21 attached to the wafer 11 is performed. FIG. 3 is a perspective view schematically showing a configuration example of the grinding device 2 used in the protective member processing step. As shown in FIG. 3, 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. FIG. 4 is a cross-sectional view schematically showing the structure of the chuck table 14. In FIG. 4, for convenience of explanation, the shape and the like of the chuck table 14 are exaggerated. As shown in FIGS. 3 and 4, 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 14a is formed in a substantially conical shape (shape corresponding to the side surface of a cone), and is connected to a suction source (not shown) via a suction path 14b 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. In addition, although the conical shape of the holding surface 14a is exaggerated in FIG. 4, the difference (height difference) of the highest point of the holding surface 14a and the lowest point is about 15 micrometers-20 micrometers in fact.

  The chuck table 14 is connected to a rotational drive source (not shown) such as a motor, and is generally in the Z-axis direction (vertical direction) so that the conical apex 14c of the holding surface 14a is the center of rotation. Rotate around parallel rotation axes. Further, the chuck table 14 is moved in the X axis direction together with the X axis moving table 8 a by the above-described X axis moving mechanism 8.

  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. 5 is a perspective view schematically showing the structure of the grinding wheel 36. As shown in FIG. As shown in FIG. 5, the grinding wheel 36 according to the present 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.

  FIG. 6 is a plan view for explaining the protective member processing step, and FIG. 7 is a partial cross-sectional side 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 the wafer 11 is sucked and held by the chuck table 14, the chuck table 14 is moved by the X-axis moving mechanism 8 to grind the position corresponding to the conical apex 14c of the holding surface 14a as shown in FIG. The positional relationship between the chuck table 14 and the grinding wheel 36 is adjusted so that the grindstone 40 passes.

  Next, the chuck table 14 and the grinding wheel 36 are each rotated in a predetermined direction at a predetermined rotation number. The rotation speed of the chuck table 14 is, for example, about 10 rpm, and the rotation speed of the grinding wheel 36 is, for example, about 4000 rpm. However, the number of rotations of the chuck table 14 and the number of rotations of the grinding wheel 36 are not limited to these.

  Then, the grinding wheel 36 is lowered at a predetermined speed to bring the grinding stone 40 into contact with the other surface side of the base 23 of the protective member 21 while supplying the liquid (processing liquid) from the plurality of supply ports 38d. The speed at which the grinding wheel 36 is lowered is, for example, about 0.1 μm / s, and the liquid supply amount is, for example, about 3.0 L / min to about 7.0 L / min. However, the speed at which the grinding wheel 36 is lowered and the supply amount of liquid are not limited to these.

  As a result, as shown in FIG. 7, the base material 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, in the present embodiment, the plurality of grooves 23a are formed on the other surface side of the base material 23 before the protective member 21 is processed. Therefore, the liquid supplied in the protective member processing step is easily accumulated in the plurality of grooves 23a, and the cooling of the protective member 21 and the grinding stone 40 can be promoted. Further, the grinding stone 40 can be easily cut into the base material 23 by the plurality of grooves 23a, and the protective member 21 (base material 23) can be efficiently (effectively) 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 protection member according to the present embodiment, after forming the plurality of grooves 23 a on the other surface side of the base 23 of the protection member 21, the grinding stone 40 is brought into contact while supplying the liquid. Since the protective member 21 is processed, the protective member 21 and the grinding stone 40 can be properly cooled by the liquid accumulated in the plurality of grooves 23a, and the protective member 21 can be processed while suppressing clogging of the grinding stone 40. Further, by forming the plurality of grooves 23a in the base material 23, the grinding stone 40 can be easily cut into the base material 23, and the protective member 21 can be processed efficiently. Thus, 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.

  Further, in the above embodiment, the chuck table 14 and the grinding wheel 36 are both rotated in the counterclockwise direction in plan view of FIG. 6, but there is a special limitation in the direction of rotating the chuck table 14 and the grinding wheel 36 Absent.

  Furthermore, in the above embodiment, in the method of cutting the rotated annular cutting blade 9 into the base 23 of the protective member 21, the plurality of grooves 23 a having a depth not reaching the adhesive layer is formed on the other side of the base 23. Although formed on the surface side, a plurality of grooves 23a can also be formed by, for example, a method of irradiating the base material 23 with a laser beam. In this case, it is preferable to use a laser beam of a wavelength that is easily absorbed by the base material 23.

  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)
DESCRIPTION OF SYMBOLS 15 Device 21 Protective member 23 Base material 25 Adhesive material layer 1 Cutting device 3 Chuck table 3a Holding surface 5 Cutting unit 7 Spindle 9 Cutting blade 2 Grinding device 4 Base 6 Support structure 8 X axis moving mechanism 8a X axis moving table 10 Dustproof Drip-proof cover 12 Operation panel 14 Chuck table 14a Holding surface 14b Suction path 14c Top 16 Z axis moving 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 38 a upper surface 38 b lower surface 38 c opening 38 d supply port 40 grinding wheel

Claims (3)

A grinding table having a conical holding surface for holding a wafer and rotating so that the apex of the conical shape is the center of rotation, and a grinding wheel having a plurality of annularly arranged grinding wheels A processing method of a protection member, wherein the protection member attached to the wafer is processed using a grinding apparatus including a grinding unit,
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,
Forming a plurality of grooves having a depth not reaching the adhesive layer on the other surface side of the substrate;
The back side of the wafer is held by the holding surface, and the chucking wheel and the grinding wheel are respectively rotated to bring the grinding wheel into contact with the other side of the base of the protective member. And a protective member processing step of processing the protective member so as to reduce the thickness of the substrate.
In the protective member processing step, while the liquid is supplied to the protective member, the position of the chuck table and the grinding wheel is matched so that the grinding wheel passes through the position corresponding to the apex of the conical shape. A processing method of a protection member characterized by processing a member.   In the groove forming step, a plurality of grooves having a depth not reaching the adhesive layer are formed on the other surface side of the base material by cutting the rotated annular cutting blade into the base material of the protective member. The method for processing a protective member according to claim 1, wherein the forming is performed.   In the groove forming step, a plurality of grooves having a depth not reaching the adhesive layer are formed on the other surface side of the base by irradiating the base with a laser beam. The processing method of the protection member as described in-.