Grinding method and support base

Abstract

To suppress an adhesive protruding from an outer peripheral end part of work-piece from being ground, in grinding the work-piece while attaching the work-piece to a support base with the adhesive.SOLUTION: A grinding method for grinding work-piece comprises: an attaching step of attaching work-piece to a support base, using a support base which has a support part having an upper surface whose areas are equal to or more than areas defined by an outer shape of the work-piece and an annular outer periphery part, provided at the outer periphery part of the support part, whose upper surface is positioned at a position lower than the upper surface of the support part, with an adhesive arranged between the support part and the work-piece; and a grinding step of grinding the work-piece using a grinding wheel, while holding the support base with a holding surface of a chuck table, after the attaching step. In the attaching step, the adhesive pushed out to the outside more than an outer peripheral end part of the work-piece by pressing force can move to the annular outer periphery part of the support base.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a grinding method for grinding a workpiece attached to a support base via an adhesive, and a support base that is attached to the support base via an adhesive and supports the workpiece during grinding.

Background Art

[0002] Various electronic devices such as mobile phones are equipped with device chips. The device chips are manufactured by processing a wafer (workpiece) on which devices such as ICs (Integrated Circuits) are formed on the surface side.

[0003] For example, after grinding the back side of the workpiece with a grinding device to thin it, the thinned workpiece is cut with a cutting device along each division planned line set in a grid pattern on the surface of the workpiece, so that the workpiece is divided into a plurality of device chips.

[0004] During grinding of the workpiece, the front side of the workpiece is sucked and held by a chuck table, and the back side of the workpiece is ground with a grinding wheel. However, when the workpiece is ground and thinned, there is a problem that the workpiece warps and cracks occur.

[0005] To solve this problem, a grinding method is known in which the front side of the workpiece is attached to a support base and then the back side of the workpiece is ground (see, for example, Patent Document 1). To attach the front side of the workpiece to the support base, an adhesive is placed between the workpiece and the support base, and then the workpiece is pressed against the support base (see, for example, Patent Document 2).

[0006] However, when the workpiece is pressed against the support base, the adhesive oozes out from the outer peripheral end of the workpiece, and the adhesive adheres to the outer peripheral end of the workpiece. Moreover, the adhesive may protrude from the front surface to the back surface of the outer peripheral side surface of the workpiece.

[0007] When grinding a workpiece, if the adhesive is ground together with the workpiece, clogging occurs on the grinding wheel, making it difficult to stably grind the workpiece. On the other hand, a technique is known in which an annular groove having a predetermined width is formed in the support base by cutting the upper surface side of the support base, and the excess adhesive is captured by this annular groove (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, when cutting the support base to form the annular groove, it takes time and effort for cutting. In addition, the amount of the adhesive protruding outward in the radial direction of the workpiece during attachment may be non-uniform in the circumferential direction of the workpiece.

[0010] When the amount of protrusion outward in the radial direction of the workpiece is non-uniform, the protruding adhesive may not fit properly into the annular groove having a uniform predetermined width and may be ground together with the workpiece during grinding of the workpiece, which may inhibit stable grinding of the workpiece.

[0011] The present invention has been made in view of such problems, and an object thereof is to suppress grinding of the adhesive protruding from the outer peripheral end portion of the workpiece when grinding the workpiece in a state where the workpiece is attached to the support base with the adhesive.

Means for Solving the Problems

[0012] According to one aspect of the present invention, It is a disk-shaped wafer a grinding method for grinding a workpiece, having an upper surface with an area equal to or larger than the area defined by the outer shape of the workpiece and is disk-shapedIt has a support portion and an annular outer peripheral portion provided on the outer peripheral portion of the support portion and having an upper surface located at a position lower than the upper surface of the support portion. and the lower surface of the support portion and the lower surface of the annular outer peripheral portion are flush with each other and constitute the lower surface of the support base A pasting step of pasting the workpiece to the support base by pressing the workpiece against the support base with an adhesive provided between the support portion and the workpiece using the support base; and a grinding step of holding the support base on the holding surface of the chuck table and grinding the workpiece with a grinding wheel after the pasting step. In the pasting step, a grinding method is provided in which the adhesive extruded outside the outer peripheral end of the workpiece by pressing is movable to the annular outer peripheral portion of the support base.

[0013] According to another aspect of the present invention, via an adhesive It is a disk-shaped wafer A support base that is attached to a workpiece and supports the workpiece during grinding of the workpiece, and has an upper surface with an area equal to or larger than the area defined by the outer shape of the workpiece. and is disk-shaped It includes a support portion and an annular outer peripheral portion provided on the outer peripheral portion of the support portion and having an upper surface located at a position lower than the upper surface of the support portion. the lower surface of the support portion and the lower surface of the annular outer peripheral portion are flush with each other and constitute the lower surface of the support base A support base is provided.

Advantages of the Invention

[0014] In the pasting step of the grinding method according to one aspect of the present invention, using a support base having a support portion with an area equal to or larger than the area defined by the outer shape of the workpiece and an annular outer peripheral portion provided on the outer peripheral portion of the support portion and having an upper surface located at a position lower than the upper surface of the support portion, with an adhesive provided between the support portion and the workpiece, the workpiece is pasted to the support base by pressing the workpiece against the support base.

[0015] Due to the pressing in the pasting step, the adhesive extruded outside the outer peripheral end of the workpiece in the radial direction of the workpiece is movable to the annular outer peripheral portion of the support base, so the adhesive does not move above a predetermined height position where the grinding wheel passes in the grinding step after the pasting step. Therefore, in the grinding step, grinding of the adhesive can be suppressed.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

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Figure 6

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Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0017] With reference to the accompanying drawings, an embodiment according to one aspect of the present invention will be described. First, the support base 2 according to the first embodiment will be described. FIG. 1(A) is a cross-sectional view of the support base 2, and FIG. 1(B) is a top view of the support base 2.

[0018] The support base 2 is formed of a material having a coefficient of thermal expansion close to that of the workpiece 11 (see FIG. 3). For example, when the workpiece 11 is a wafer formed of a compound semiconductor such as gallium arsenide (GaAs) or silicon carbide (SiC), or sapphire, a support base 2 formed of glass such as borosilicate glass, silicon (Si), ceramics, or the like is used.

[0019] The support base 2 has a disc-shaped support portion 4. The circular upper surface 4a of the support portion 4 has an area equal to or larger than the area of the circle (outer shape) defined by the diameter of the workpiece 11. For example, the upper surface 4a has a diameter that is larger than the diameter of the disc-shaped workpiece 11 by a predetermined value of 200 μm or more and 500 μm or less.

[0020] The thickness of the support portion 4 is appropriately adjusted according to the material of the support base 2. For example, when the support base 2 is formed of glass, ceramics, or the like, the thickness of the support portion 4 is set to a predetermined value of 0.5 mm or more and 1.5 mm or less.

[0021] An annular outer peripheral portion 6 having a thickness thinner than that of the support portion 4 is provided substantially concentrically with the support portion 4 over the entire circumference of the outer peripheral portion of the support portion 4. For example, the thickness of the annular outer peripheral portion 6 is thinner than the thickness of the support portion 4 by a predetermined value of 0.1 mm or more and 1.0 mm or less. Also, the outer diameter of the annular outer peripheral portion 6 is larger than the diameter of the support portion 4 by, for example, 20 mm.

[0022] The lower surface of the support portion 4 and the lower surface of the annular outer peripheral portion 6 are substantially flush with each other, forming the lower surface 2b of the support base 2. The upper surface 6a of the annular outer peripheral portion 6 is located at a position lower than the upper surface 4a of the support portion 4, and an annular step portion 2a is formed at the boundary between the annular outer peripheral portion 6 and the support portion 4.

[0023] Next, a grinding method for grinding the workpiece 11 using the support base 2 will be described. FIG. 2 is a flowchart of the grinding method. When grinding the workpiece 11, as shown in FIG. 3, the surface 11a side of the workpiece 11 is attached to the upper surface 4a of the support portion 4 via the adhesive 13 (attachment step S10).

[0024] The workpiece 11 of the present embodiment is a disc-shaped wafer formed of a compound semiconductor. However, the workpiece 11 may be a wafer or a substrate formed of a semiconductor material such as silicon, glass, ceramics, resin, metal, etc., as long as it is disc-shaped with substantially the same diameter as the upper surface 4a.

[0025] Chamfered portions 11d A 、11d B (also referred to as bevel portions) are respectively formed over the entire circumference.

[0026] The workpiece 11 has a predetermined diameter and a predetermined thickness corresponding to the diameter. The diameter of the workpiece 11 is defined by the outer peripheral end portion 11c of the workpiece 11. The outer peripheral end portion 11c is located substantially in the middle of the distance between the surface 11a and the back surface 11b (i.e., the thickness of the workpiece 11).

[0027] The surface 11a side of the workpiece 11 is partitioned into a plurality of rectangular regions by a plurality of division planned lines (not shown) intersecting each other. Devices (not shown) such as LEDs (Light Emitting Diodes) and ICs (Integrated Circuits) are formed in each region.

[0028] When attaching this workpiece 11 to the support portion 4, for example, the adhesive 13 is used. The adhesive 13 of the present embodiment is wax. However, a thermoplastic resin that softens by heat may be used as the adhesive 13.

[0029] In the attaching step S10, an alignment device (not shown) is used to substantially align the center of the upper surface 4a of the support portion 4 with the center of the surface 11a of the workpiece 11. The alignment device has a predetermined sensor (not shown) for measuring the coordinates of the outer peripheral edge of the upper surface 4a.

[0030] The predetermined sensor is, for example, a laser displacement sensor. If the coordinates of three different points on the outer peripheral edge of the upper surface 4a can be obtained using the laser displacement sensor, the coordinates of the center of the upper surface 4a can be calculated. However, instead of the laser displacement sensor, the coordinates of the center of the upper surface 4a may be calculated based on an image obtained by imaging the upper surface 4a with a camera.

[0031] The alignment device has a control unit (not shown) for controlling the operation of the predetermined sensor and other components and performing predetermined calculations. The control unit is constituted by a computer including, for example, a processor (processing device) typified by a CPU (Central Processing Unit) and a memory.

[0032] The alignment device has a chuck table (not shown) for sucking and holding the workpiece 11. With the back surface 11b side of the workpiece 11 held by the chuck table, the coordinates of the center of the surface 11a are calculated by measuring the coordinates of three different points on the outer peripheral end portion 11c using the above-described predetermined sensor.

[0033] The alignment device includes an adhesive application unit (not shown) for applying an adhesive 13 to the upper surface 4a of the support portion 4. After a predetermined amount of the adhesive 13 is applied to the central portion of the upper surface 4a, the workpiece 11 is conveyed to the support base 2 by a conveyance unit (not shown) of the alignment device so that the center of the upper surface 4a and the center of the surface 11a are substantially aligned.

[0034] In addition, if the outer peripheral end portion 11c of the workpiece 11 is within the upper surface 4a of the support portion 4 in a top view, a certain degree of misalignment between the centers of the upper surface 4a and the surface 11a is allowed. For example, a misalignment of about 100 μm between the centers of the upper surface 4a and the surface 11a is allowed.

[0035] In the pasting step S10, in order to press the workpiece 11 against the support portion 4 via the adhesive 13, for example, a vacuum press machine (not shown) is used. The vacuum press machine has a metal chamber (not shown) in which the support base 2 is disposed inside.

[0036] At the lower part of the chamber, a temperature adjustment mechanism (not shown) for controlling the temperature inside the chamber is provided. The temperature adjustment mechanism includes a heater and a cooling mechanism by water cooling.

[0037] Inside the chamber, a ring-shaped regulating member (not shown) for restricting the lateral movement of the support base 2 during pressing is provided. Further, above the regulating member, an airbag (not shown) that can expand substantially uniformly downward is provided.

[0038] When performing the pasting step S10, first, using the above-described alignment device, with the adhesive 13 provided between the support portion 4 and the workpiece 11, the upper surface 4a and the surface 11a are faced so that the centers of the upper surface 4a and the surface 11a substantially coincide.

[0039] Next, after placing the support base 2 on which the workpiece 11 is placed via the adhesive 13 inside the radial inner side of the regulating member in the chamber of the vacuum press machine, the inside of the chamber is set to a predetermined degree of vacuum state.

[0040] In this state, while heating the support base 2 with a heater, the airbag is inflated, and the workpiece 11 is pressed against the support base 2 with a predetermined pressure. The predetermined pressure is, for example, a value of 0.05 MPa or more and 0.3 MPa or less.

[0041] FIG. 3 is a diagram showing the pasting step S10. In FIG. 3, the state where the workpiece 11 is pressed is indicated by an arrow. In addition, in the pasting step S10, instead of the above-described vacuum press machine, other press machines may be used.

[0042] The adhesive 13 softened by heating is pushed out radially of the workpiece 11 to the outside of the outer peripheral end portion 11c of the workpiece 11 and is movable to the annular outer peripheral portion 6. However, in the present embodiment, the pushed-out adhesive 13 does not move above a predetermined height position.

[0043] Specifically, the pushed-out adhesive 13 slightly rises along the chamfered portion 11d on the surface 11a side, but most of it moves to the annular outer peripheral portion 6 (see Fig. 7(A)). Therefore, the rising position of the adhesive 13 is lower than the height position corresponding to the finished thickness 11e of the workpiece 11 thinned using the grinding device 8 (see Fig. 7(B)). A After pressing for a predetermined time, the support base 2 is cooled to cure the adhesive 13. Thereby, a workpiece unit 15 in which the workpiece 11 is attached to the support base 2 via the adhesive 13 is formed. Fig. 4(A) is a cross-sectional view of the workpiece unit 15 after the attachment step S10.

[0044] Fig. 4(B) is a top view of the workpiece unit 15 after the attachment step S10. As shown in Fig. 4(B), the amount of the adhesive 13 protruding radially outward of the workpiece 11 may be non-uniform in the circumferential direction of the workpiece 11.

[0045] In the present embodiment, since the entire upper surface 6a of the annular outer peripheral portion 6 is at a position lower than the upper surface 4a of the support portion 4, even if the adhesive 13 protrudes non-uniformly radially outward of the workpiece 11, the adhesive 13 can be released to the annular outer peripheral portion 6. Therefore, the rising position of the adhesive 13 can always be lower than the height position corresponding to the finished thickness 11e.

[0046] After the attachment step S10, a grinding step S20 is performed. In the grinding step S20, the grinding device 8 shown in Fig. 5 is used. The grinding device 8 has a disk-shaped chuck table 10. The chuck table 10 has a disk-shaped frame body 12 formed of ceramics.

[0047]

[0048] ​ At the center of the frame body 12, a disk-shaped recess having a predetermined depth is formed. A predetermined flow path (not shown) is formed in the frame body 12. One end of this flow path is exposed to the recess, and a suction source (not shown) such as an ejector is connected to the other end of this flow path.

[0049] The recess is formed of porous ceramics, and a disk-shaped porous plate 14 having substantially the same diameter as the inner diameter of the recess is fixed thereto. When the suction source is operated, a negative pressure is transmitted to the porous plate 14 through a predetermined flow path.

[0050] The upper surface of the frame body 12 and the upper surface of the porous plate 14 constitute a substantially flush holding surface 10a. The holding surface 10a has a conical shape in which the central portion thereof protrudes slightly compared to the outer peripheral portion. A first rotation drive source (not shown) such as a motor is provided below the chuck table 10.

[0051] The chuck table 10 is rotated around a predetermined rotation axis by the first rotation drive source. The predetermined rotation axis is slightly inclined with respect to the Z-axis direction so that a part of the holding surface 10a is substantially parallel to a predetermined plane (for example, a horizontal plane) orthogonal to the Z-axis direction (for example, the vertical direction).

[0052] Above the holding surface 10a, a grinding unit 16 is fixed. A ball screw type grinding feed unit (not shown) for moving the grinding unit 16 along the Z-axis direction (for example, the vertical direction) is connected to the grinding unit 16.

[0053] The grinding unit 16 has a cylindrical spindle housing 18 arranged along the Z-axis direction. A part of a cylindrical spindle 20 is rotatably accommodated in the spindle housing 18.

[0054] A second rotation drive source (not shown) such as a motor is provided at the upper end of the spindle 20. The lower end of the spindle 20 protrudes below the bottom of the spindle housing 18.

[0055] At the lower end of the spindle 20, the central part on the upper surface side of the disk-shaped mount 22 is fixed. An annular grinding wheel 24 is attached to the lower surface side of the mount 22. The grinding wheel 24 has an annular wheel base 26 formed of metal.

[0056] On the lower surface side of the wheel base 26, a plurality of grinding wheels 28 are annularly arranged at predetermined intervals along the circumferential direction of the wheel base 26. Each grinding wheel 28 has abrasive grains such as diamond and cBN (cubic boron nitride), and a binder for fixing the abrasive grains such as ceramics and resin.

[0057] In the grinding step S20, first, after placing the workpiece unit 15 on the chuck table 10 so that the lower surface 2b contacts the holding surface 10a, the support base 2 is sucked and held by the holding surface 10a. At this time, the workpiece unit 15 deforms following the shape of the holding surface 10a. FIG. 5 is a partial cross-sectional side view of the workpiece unit 15 and the like held by the holding surface 10a.

[0058] After the suction holding, the chuck table 10 and the spindle 20 are rotated in a predetermined direction, and while supplying grinding water such as pure water to the contact area between the grinding wheel 28 and the workpiece 11, the grinding unit 16 is fed at a predetermined grinding feed rate.

[0059] FIG. 6 is a partial cross-sectional side view showing the grinding step S20. As shown in FIG. 6, the workpiece 11 is ground and thinned to a finish thickness 11e (see FIG. 7(B)) by the grinding wheel 24 while being supported by the support base 2. FIG. 7(A) is a cross-sectional view of the workpiece unit 15 near the stepped portion 2a before the grinding step S20.

[0060] As shown in FIG. 7(A), the adhesive 13 pushed out to the outer side in the radial direction of the workpiece 11 slightly rises along the chamfered portion 11d on the surface 11a side, but most of it moves to the annular outer peripheral portion 6. Therefore, the adhesive 13 does not move above the predetermined height position through which the grinding wheel 28 passes. A and moves slightly upward along the chamfered portion 11d on the surface 11a side, but most of it moves to the annular outer peripheral portion 6. Therefore, the adhesive 13 does not move above the predetermined height position through which the grinding wheel 28 passes.

[0061] FIG. 7(B) is a cross-sectional view of the workpiece unit 15 in the vicinity of the stepped portion 2a after the grinding step. As shown in FIG. 7(B), the rising position of the adhesive 13 extruded outward is lower than the height position corresponding to the finish thickness 11e of the workpiece 11 after thinning. Therefore, in the grinding step S20, grinding of the adhesive 13 can be suppressed.

[0062] Next, a comparative example will be described in which the workpiece 11 is ground after being attached to a substantially flat support base 32 different from the support base 2. FIG. 8(A) is a diagram showing the attachment step S10 according to the comparative example.

[0063] In the attachment step S10 of the comparative example, the surface 11a side of the workpiece 11 is attached to the upper surface 32a of a disk-shaped support base 32 having both the upper surface 32a and the lower surface 32b substantially flat via the adhesive 13. When attaching the workpiece 11 to the support base 32, an alignment device and a vacuum press are used in the same manner as in the first embodiment.

[0064] In this way, a workpiece unit 17 in which the workpiece 11 is attached to the support base 32 via the adhesive 13 is formed. FIG. 8(B) is a cross-sectional view of the workpiece unit 17 after the attachment step S10 according to the comparative example.

[0065] However, in the comparative example, the extruded adhesive 13 rises along the chamfered portion 11d on the surface 11a side, and its rising position is higher than, for example, the height position corresponding to the finish thickness 11e of the workpiece 11 (see FIG. 9(B)). A FIG. 9(A) is a cross-sectional view of the vicinity of the outer peripheral end portion 11c of the workpiece 11 before the grinding step S20 according to the comparative example. Further, FIG. 9(B) is a cross-sectional view of the vicinity of the outer peripheral end portion 11c of the workpiece 11 after the grinding step S20 according to the comparative example.

[0066]

[0067] ​As shown in Fig. 9(B), in the comparative example, since a part 13a of the adhesive 13 protruding to a position higher than the height position corresponding to the finish thickness 11e is ground, clogging occurs in the grinding wheel 28, making it difficult to stably grind the workpiece 11.

[0068] On the other hand, in the first embodiment, the adhesive 13 extruded outward from the outer peripheral end portion 11c in the radial direction of the workpiece 11 can move to the annular outer peripheral portion 6 of the support base 2. Specifically, the adhesive 13 does not move above a predetermined height position through which the grinding wheel 28 passes. Therefore, in the grinding step S20, grinding of the adhesive 13 can be suppressed.

[0069] Next, a second embodiment will be described. Fig. 10(A) is a cross-sectional view of the support base 42 in the second embodiment. The shape of the support base 42 in the second embodiment is substantially the same as that of the support base 2 in the first embodiment.

[0070] However, the support base 42 has an annular convex portion 44 protruding from the outer peripheral end portion of the annular outer peripheral portion 6 and protruding more than the upper surface 6a in the thickness direction of the support base 42. However, the height position of the upper surface 44a of the annular convex portion 44 is lower than the upper surface 4a of the support portion 4. That is, the height position of the upper surface 44a is between the height position of the upper surface 4a and the height position of the upper surface 6a.

[0071] Therefore, in the pasting step S10, when the workpiece 11 is pressed against the support base 42 via the adhesive 13, the adhesive 13 extruded outward from the outer peripheral end portion 11c of the workpiece 11 in the radial direction of the workpiece 11 can move to the annular outer peripheral portion 6.

[0072] Fig. 10(B) is a cross-sectional view of the workpiece unit 19 in the second embodiment. Also in the pasting step S10 of the second embodiment, the adhesive 13 does not move above a predetermined height position through which the grinding wheel 28 passes. Therefore, in the grinding step S20, grinding of the adhesive 13 can be suppressed.

[0073] Next, a third embodiment will be described. FIG. 11(A) is a cross-sectional view of the support base 52 in the third embodiment. The support base 52 of the third embodiment is substantially the same as the support base 2 of the first embodiment.

[0074] The annular outer peripheral portion 6 gradually thickens as it goes outward in the radial direction of the support base 2. That is, the thickness of the annular outer peripheral portion 6 is the smallest at the boundary between the support portion 4 and the annular outer peripheral portion 6, and the largest at the outer peripheral end of the support base 2. However, the upper surface 6a of the annular outer peripheral portion 6 is also lower than the upper surface 4a of the support portion 4 at the outer peripheral end of the support base 2.

[0075] Therefore, in the pasting step S10, when the workpiece 11 is pressed against the support base 42 via the adhesive 13, the adhesive 13 extruded outward of the outer peripheral end 11c of the workpiece 11 in the radial direction of the workpiece 11 can move to the annular outer peripheral portion 6.

[0076] FIG. 11(B) is a cross-sectional view of the workpiece unit 21 in the third embodiment. Also in the pasting step S10 of the third embodiment, since the adhesive 13 does not move above the predetermined height position through which the grinding wheel 28 passes, the grinding of the adhesive 13 can be suppressed in the grinding step S20.

[0077] Next, a fourth embodiment will be described. The support base 62 according to the fourth embodiment is rectangular instead of disc-shaped. FIG. 12(A) is a cross-sectional view of the support base 62 in the fourth embodiment, and FIG. 12(B) is a top view of the support base 62 in the fourth embodiment.

[0078] The support base 62 has a rectangular support portion 4. On the upper surface 4a of the support portion 4, for example, a rectangular package substrate (workpiece) in which a plurality of device chips are sealed with a molding resin is pasted. The rectangular upper surface 4a has an area larger than the rectangular area defined by the outer shape of the package substrate (not shown).

[0079] For example, the length of the long side of the upper surface 4a is larger than the length of the long side of the package substrate by a predetermined value of 200 μm or more and 500 μm or less, and the length of the short side of the upper surface 4a is larger than the length of the short side of the package substrate by a predetermined value of 200 μm or more and 500 μm or less.

[0080] An annular outer peripheral portion 6 having a rectangular shape and a thickness thinner than that of the support portion 4 is provided on the outer peripheral portion of the support portion 4 over the entire circumference of the support portion 4. For example, the long side of the annular outer peripheral portion 6 is 20 mm larger than the long side of the support portion 4, and the short side of the annular outer peripheral portion 6 is 20 mm larger than the short side of the support portion 4.

[0081] The support base 2 is formed of a resin having a coefficient of thermal expansion close to that of the thermosetting resin of the package substrate. For example, when the support base 2 is formed of a resin, the thickness of the support portion 4 is set to a predetermined value of 0.5 mm or more and 1.5 mm or less.

[0082] The lower surface of the support portion 4 and the lower surface of the annular outer peripheral portion 6 are substantially flush with each other and constitute the lower surface 2b of the support base 2. Further, the upper surface 6a of the annular outer peripheral portion 6 is at a position lower than the upper surface 4a of the support portion 4. Therefore, an annular step portion 2a is formed at the boundary between the annular outer peripheral portion 6 and the support portion 4.

[0083] Also in the attachment step S10 of the fourth embodiment, when the package substrate is pressed against the support base 62 via the adhesive 13, the adhesive 13 extruded outside the outer peripheral end portion of the package substrate in the long side direction and the short side direction of the package substrate can move to the annular outer peripheral portion 6.

[0084] Therefore, also in the attachment step S10 of the fourth embodiment, above the predetermined height position through which the grinding wheel 28 passes, the adhesive 13 does not move, so that in the grinding step S20, grinding of the adhesive 13 can be suppressed.

[0085] In addition, the structures, methods, etc. according to the above-described embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention. The rectangular workpiece in the fourth embodiment is not limited to the package substrate, and may be a substrate formed of glass, ceramics, metal, or the like.

Explanation of Reference Numerals

[0086] 2: Support base, 2a: Step portion, 2b: Lower surface 4: Support portion, 4a: Upper surface, 6: Annular outer peripheral portion, 6a: Upper surface 8: Grinding device, 10: Chuck table, 10a: Holding surface 12: Frame body, 14: Porous plate 11: Workpiece, 11a: Surface, 11b: Back surface 11c: Outer peripheral end portion, 11d A ,11d B : Chamfered portion, 11e: Finishing thickness 13: Adhesive, 13a: Part, 15, 17, 19, 21: Workpiece unit 16: Grinding unit, 18: Spindle housing, 20: Spindle 22: Mount, 24: Grinding wheel, 26: Wheel base, 28: Grinding stone 32: Support base, 32a: Upper surface, 32b: Lower surface 42: Support base, 44: Annular convex portion, 44a: Upper surface 52, 62: Support base

Claims

A grinding method for grinding a workpiece that is a disk-shaped wafer, comprising: a support base having an upper surface with an area equal to or larger than the area defined by the outer shape of the workpiece and being disk-shaped, and an annular outer peripheral portion provided at the outer peripheral portion of the support base and having an upper surface positioned at a lower position than the upper surface of the support base, wherein the lower surface of the support base and the lower surface of the annular outer peripheral portion are flush with each other and constitute the lower surface of the support base; and a pasting step of pasting the workpiece onto the support base by pressing the workpiece onto the support base with an adhesive provided between the support base and the workpiece; a grinding step of holding the support base on the holding surface of a chuck table and grinding the workpiece with a grinding wheel after the pasting step; wherein, in the pasting step, the adhesive extruded outward from the outer peripheral end portion of the workpiece can move to the annular outer peripheral portion of the support base by pressing.

2. A support base that is attached to a workpiece that is a disk-shaped wafer via an adhesive and supports the workpiece during grinding of the workpiece, the support base comprising a support portion having an upper surface with an area equal to or larger than the area defined by the outer shape of the workpiece and being disk-shaped, and an annular outer peripheral portion provided at the outer peripheral portion of the support portion and having an upper surface positioned at a lower position than the upper surface of the support portion; wherein the lower surface of the support portion and the lower surface of the annular outer peripheral portion are flush with each other and constitute the lower surface of the support base.

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