JP7321649B2 - Grinding method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a grinding method for grinding a plate-like workpiece having warpage.

In the manufacturing process of a semiconductor device chip, a plurality of planned division lines are set in a grid pattern on the front side of a semiconductor wafer, and ICs (Integrated Circuits) and LSIs (Large Scale Integration) are placed in respective regions partitioned by the plurality of planned division lines. form a device such as

After that, for example, after grinding the back side of the wafer with a grinding device until the wafer has a predetermined thickness, the wafer is cut with a cutting device along each division line of the wafer thinned by grinding, thereby producing a semiconductor. A device chip is manufactured.

The cutting device has a cutting unit including a cutting blade having an annular cutting edge, and a chuck table provided below the cutting unit. The chuck table includes a metal frame having a disk-shaped recess, and a porous plate inserted into the recess of the frame and fixed to the frame with an adhesive (see, for example, Patent Document 1). The bottom surface of the porous plate is located on the bottom side of the frame, and the top surface of the porous plate is a substantially flat surface and is flush with the top surface of the frame located on the outer periphery of the recess.

In order to manufacture such a porous plate, for example, high-hardness ceramic particles made of alumina or the like are placed in a mold having a disk-shaped space, compression-molded, and then sintered to form a disk. form a fired body. Thereafter, by grinding or polishing the front surface, rear surface, and side surface of the sintered body, a porous plate having a substantially flat holding surface that becomes a contact surface with the workpiece is manufactured.

By the way, when grinding a sintered body, one side of the sintered body is held by a chuck table having a conical holding surface, and the other side of the sintered body is ground (see, for example, Patent Document 2). However, the sintered body usually has a warp, and even if the other side of the sintered body is ground while holding the sintered body so that one side of the body is greatly deformed, the porous plate after grinding has Warpage remains.

JP-A-2008-62476 JP 2015-9295 A

If the porous plate remains warped after grinding, adhesion failure or the like occurs between the porous plate and the frame. Furthermore, if a workpiece is machined using a machining apparatus having a chuck table composed of a porous plate and a frame that are still warped, machining defects will occur.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object of the present invention is to reduce the warpage of a workpiece after grinding when grinding a warped plate-like workpiece (for example, a porous plate).

According to one aspect of the present invention, the convex first surface and the concave second surface of the warped plate-like workpiece are arranged in an annular shape on the wheel base and on one side of the wheel base. A grinding method for grinding with a grinding unit having a grindstone portion that is coated with a grindstone, wherein a first protective member is attached to the outer peripheral portion of the second surface of the work, and the second surface side of the work and the second surface of the work are separated from each other. a first affixing step of forming a closed space with one protective member; and in a state in which the space is formed, the first protective member is sucked by a holding surface of a disk-shaped first holding table. a first holding step of holding the first surface of the work in a state in which the rotation axis of the first holding table and the rotation axis of the grinding unit are parallel and the space is formed; a protective member stripping step of stripping the first protective member from the workpiece after the first grinding step; and after the protective member stripping step, the second surface. a second holding step of sucking and holding the first surface side of the work with the holding surface of a disk-shaped second holding table so that the workpiece is exposed, and holding the work with the holding surface of the second holding table and a second grinding step of grinding the second surface side of the processed workpiece with the grinding unit , wherein the workpiece is a porous plate formed through compression molding and firing of ceramic particles, and A grinding method is provided wherein the first protective member is a protective tape .

Preferably, the first holding table and the second holding table are the same table.

Preferably, the holding surface of the first holding table has a planar shape, and the holding surface of the second holding table is formed so as to have a convex shape as it goes from the outer peripheral portion to the central portion, In the second grinding step, a portion of the holding surface of the second holding table located below the contact area between the grindstone portion and the workpiece is parallel to the grinding surface defined by the lower surface of the grindstone portion. The workpiece is ground by the grinding unit while the rotating shaft of the second holding table is tilted so as to be .

Preferably, in the protective member peeling step, the first protective member is peeled off from the workpiece after a second protective member is attached to the first surface ground in the first grinding step. do.

In the grinding method according to one aspect of the present invention, first, a first protective member is attached to the outer peripheral portion of the concave second surface of the workpiece, and the space closed by the second surface side and the first protective member (first attachment step). Then, the first protective member is held by the holding surface of the first holding table in a state where the above-described space is formed (first holding step). Thereby, the work can be held by the holding surface without deforming the work according to the shape of the holding surface.

Thereafter, the first surface side of the workpiece is ground in a state in which the rotating shaft of the first holding table and the grinding unit are parallel to each other and the space described above is formed (first grinding step). By grinding the first surface side in this manner without deforming the workpiece, the first surface of the workpiece after grinding can be made substantially flat with reduced warpage.

After the first grinding step, the first protective member is peeled off from the workpiece (protective member peeling step), and the first surface side is held by the holding surface of the second holding table so that the second surface is exposed. (second holding step). Then, the second surface side of the work held by the holding surface of the second holding table is ground (second grinding step).

In the second grinding step, the second surface of the work can be uniformly ground on the basis of the first surface while the warp-reduced first surface of the work is held. In addition to reducing the thickness, the second surface side of the work can be made into a substantially flat surface with reduced warpage.

FIG. 1(A) is a cross-sectional view of a workpiece, and FIG. 1(B) is a partial cross-sectional side view of a grinding apparatus and the like according to the first embodiment. FIG. 2A is a partial cross-sectional side view showing the first grinding step, and FIG. 2B is a cross-sectional view of the workpiece after the first grinding step. FIG. 11 is a partial cross-sectional side view showing a second holding step; FIG. 4A is a partial cross-sectional side view showing the second grinding step, and FIG. 4B is a cross-sectional view of the workpiece after the second grinding step. It is a flow figure showing the grinding method of a 1st embodiment. FIG. 6(A) is a partial cross-sectional side view showing the second grinding step according to the second embodiment, and FIG. 6(B) shows the workpiece after the second grinding step according to the second embodiment. It is a sectional view. It is a partial cross-sectional side view which shows the 1st grinding step which concerns on 3rd Embodiment.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. First, a plate-like workpiece 11 to be ground in the first embodiment will be described. The workpiece 11 is, for example, a disk-shaped porous plate having a thickness of 4 mm.

The workpiece 11 is formed by, for example, filling a metal mold having a disk-shaped space with particulate aggregate made of silicon carbide, alumina, or the like, and then performing processes such as compression molding and firing. be done. FIG. 1(A) is a cross-sectional view of the workpiece 11 after firing and before grinding.

The workpiece 11 has a warp and includes a convex first surface 11a and a concave second surface 11b located on the opposite side of the first surface 11a. The work 11 has a warp amount A of, for example, about 30 μm.

The warp amount A is, for example, when the workpiece 11 is placed on the plane B so that the convex first surface 11a faces upward and the concave second surface 11b faces downward, It is defined by the maximum length from the plane B to the second surface 11b.

The warp amount A of the work 11 is obtained by sandwiching the work 11 between the plane B and the plane B' so that the first surface 11a is in contact with the plane B and the second surface 11b is in contact with the plane B' parallel to the plane B. In some cases, it may be defined by the maximum length from the plane B to the first surface 11a or the maximum length from the plane B' to the second surface 11b in the direction orthogonal to the plane B.

Next, the grinding device 2 for grinding the workpiece 11 will be described. FIG. 1B is a partial cross-sectional side view of the grinding device 2 and the like according to the first embodiment. The grinding device 2 has a disk-shaped chuck table (first holding table) 6 .

The chuck table 6 has a ceramic frame 6a. A channel (not shown) is provided in the frame 6a, and one end of this channel is connected to a suction source (not shown) such as an ejector.

The frame 6a has a concave portion formed of a disk-shaped space on the upper surface side. A substantially disk-shaped porous plate 6b having substantially the same diameter as the workpiece 11 is fixed to the recess. The porous plate 6b has substantially flat circular upper and lower surfaces, respectively.

The other end of the channel provided in the frame 6a is connected to the lower surface of the porous plate 6b. When the suction source is operated, a negative pressure is generated on the upper surface of the porous plate 6b, and the upper surface functions as a holding surface 6c.

A disk-shaped table base 8 is connected to the lower surface of the chuck table 6 . A drive mechanism (not shown) such as a motor is provided on the lower surface side of the table base 8 , and this drive mechanism is connected to the chuck table 6 .

By operating the drive mechanism, the chuck table 6 rotates around a predetermined rotation axis 6d. 6 d of this rotating shaft is orthogonal to the holding surface 6c of the porous plate 6b in the aspect which passes through the center of the holding surface 6c.

A tilt adjustment mechanism 10 having one fixed support member 10a and two movable support members 10b is provided on the lower surface side of the table base 8. As shown in FIG. One fixed support member 10a and two movable support members 10b are connected to the table base 8 while being separated from each other by 120 degrees in the circumferential direction of the table base 8. As shown in FIG. Note that FIG. 1B shows one of the two movable support members 10b.

The height of the upper end of the fixed support member 10a is fixed, but the height of the upper end of the movable support member 10b is movable in the vertical direction. For example, by adjusting the height of the upper end of the movable support member 10b, the rotary shaft 6d can be tilted at a predetermined angle with respect to the vertical direction of the grinding device 2 (Z-axis direction).

Further, for example, by matching the heights of the upper ends of one fixed support member 10a and two movable support members 10b, the rotating shaft 6d can be made parallel to the Z-axis direction.

A grinding unit 12 is provided above the chuck table 6 . A Z-axis movement mechanism (not shown) is connected to the grinding unit 12 to move the grinding unit 12 along the Z-axis direction (that is, to move it up and down).

The grinding unit 12 has a cylindrical spindle (not shown). The spindles are arranged such that the height of the cylinder is along the vertical direction. A portion of the spindle is housed in a spindle housing 14a in a rotatable manner.

A rotary drive mechanism (not shown) such as a motor is connected to the upper end of the spindle. When the rotary drive mechanism is operated, the spindle functions as a rotary shaft 14b. The upper surface side of a disk-shaped wheel mount 16 is connected to the lower end side of the spindle.

The upper side of a grinding wheel 18 is attached to the lower side of the wheel mount 16 . Grinding wheel 18 has an annular wheel base 18 a mounted on wheel mount 16 . The wheel base 18a is made of metal such as aluminum or stainless steel and has a diameter of 200 mm, for example.

A plurality of grindstones 18c (grindstone portions) are provided on the lower surface (one surface) 18b side of the wheel base 18a. Each grinding wheel is formed by, for example, mixing a bonding material such as vitrified or resinoid with abrasive grains such as diamond or cBN (cubic boron nitride) and sintering the mixture.

In this embodiment, a segmented grinding wheel 18c is used in which abrasive grains made of diamond with a grain size of #600 are fixed by a vitrified bond. A plurality of grinding wheels 18c are arranged annularly on the lower surface 18b side of the wheel base 18a (so-called segment arrangement). However, instead of the plurality of grinding wheels 18c, an annular grinding wheel (grinding wheel portion) may be provided on the lower surface 18b side (so-called continuous arrangement).

The lower surface 18d of the one or more grinding wheels 18c constitutes the grinding surface 18e of the grinding wheel 18 when the grinding wheel 18 is rotated about the rotation axis 14b. In this embodiment, the rotating shaft 14b is parallel to the Z-axis direction, and the grinding surface 18e is a plane perpendicular to the Z-axis direction.

The grinding surface 18e may be defined by the lower surfaces 18d of a plurality of grinding wheels 18c each having the same height, or the lower surface 18d of the grinding wheel 18c protruding most downward or the most of the grinding wheels 18c. In some cases, it is defined by a portion of the lower surface 18d located below.

Next, a grinding method for grinding both sides of the workpiece 11 will be described. First, a protective tape (first protective member) 13a made of resin is attached to the second surface 11b of the workpiece 11 (first attachment step (S10)).

The protective tape 13a of this embodiment is a circular tape having substantially the same diameter as the work 11, but the protective tape 13a may be a circular tape having a larger diameter than the work 11. FIG. The protective tape 13a has, for example, a laminated structure of a base material layer and an adhesive layer (glue layer).

The base layer is made of resin such as polyolefin (PO). An adhesive layer made of an adhesive resin such as an ultraviolet (UV) curable resin is formed on the entire surface of the base material layer or on the outer periphery of the base material layer.

In addition, the protective tape 13a is not limited to the laminated structure of a base material layer and an adhesive layer. For example, the masking tape 13a may have only the base layer. In this case, the protective tape 13 a is attached to the work 11 by thermocompression bonding the base material layer to the work 11 .

In the first attaching step (S10), the outer peripheral portion of the protective tape 13a is attached to the outer peripheral portion of the concave second surface 11b. However, the central portion of the second surface 11b is not in contact with the protective tape 13a, and a closed space 15 is formed between the second surface 11b side and the protective tape 13a. As a result, the interior of the work unit composed of the work 11 and the protective tape 13a becomes hollow.

After the first attaching step (S10), the protective tape 13a is held by suction on the holding surface 6c of the chuck table 6 with the space 15 formed (first holding step (S20)) (FIG. 1(B)).

As described above, since the space 15 is formed between the central portion of the second surface 11b of the workpiece 11 and the protective tape 13a, in the first holding step (S20), the entire second surface 11b side is is not held by the holding surface 6c, and the space 15 is maintained in its original shape. Therefore, the workpiece 11 can be held by the holding surface 6c without being deformed according to the shape of the holding surface 6c.

Further, in the first holding step (S20), the rotating shaft 6d of the chuck table 6 and the rotating shaft 14b of the grinding unit 12 are made parallel. As a result, the plane formed by the outer peripheral edge of the chuck table 6 during rotation of the chuck table 6 and the grinding surface 18e are positioned parallel to each other.

Next, the chuck table 6 and grinding wheel 18 are rotated in a predetermined direction. Then, the grinding unit 12 is moved downward at a grinding feed rate of 1 μm/s, for example, and the grinding wheel 18 c is pressed against the workpiece 11 . At this time, a load of, for example, 30 N is applied to the work 11, but even in this case, the shape of the space 15 is substantially maintained, and the central portion of the work 11 does not come into contact with the protective tape 13a.

In this manner, the first surface 11a side is ground while the space 15 is formed (first grinding step (S30)). FIG. 2(A) is a partial cross-sectional side view showing the first grinding step (S30), and FIG. 2(B) is a cross-sectional view of the workpiece 11 after the first grinding step (S30).

In the first grinding step (S30), the shape of the closed space 15 between the workpiece 11 and the protective tape 13a is maintained, and the first surface 11a is ground while the workpiece 11 is not deformed. As a result, the first surface 11a of the workpiece 11 after grinding can be made substantially flat with reduced warpage.

After the first grinding step (S30), the workpiece 11 is removed from the chuck table 6. FIG. Then, after affixing a resin protective tape (second protective member) 13b to the entire first surface 11a side that has been ground in the first grinding step (S30), from the first surface 11a side of the work 11 The protective tape 13a is peeled off (protective member peeling step (S40)).

Like the protective tape 13a, the protective tape 13b of the present embodiment is a circular tape having approximately the same diameter as the work 11. However, the protective tape 13b may be a circular tape having a larger diameter than the work 11. good. Moreover, although the protective tape 13b of the present embodiment has a laminated structure of a base material layer and an adhesive layer (glue layer), it may have only a base material layer.

After the protective member peeling step (S40), the workpiece 11 is transferred to the grinding device 4 having the chuck table 20 different from the chuck table 6. As shown in FIG. The chuck table 20 is disc-shaped and has a ceramic frame 20a, like the frame 6a. A channel (not shown) is also provided in the frame 20a, and one end of this channel is connected to a suction source (not shown) such as an ejector.

The frame body 20a has a concave portion formed of a disk-shaped space on the upper surface side. A substantially disk-shaped porous plate 20b having substantially the same diameter as the workpiece 11 is fixed to the recess. The bottom surface of the porous plate 20b is substantially flat and circular.

The bottom side of the porous plate 20b is connected to the other end of the channel provided in the frame 20a. When the suction source is operated, a negative pressure is generated on the upper surface of the porous plate 20b, and the upper surface functions as the holding surface 20c.

The holding surface 20c has a convex shape protruding upward from the end _20c1 of the outer peripheral portion toward the center _20c2 of the central portion. The holding surface 20c of this embodiment is a right conical convex surface. In this case, the amount of protrusion C of the upper surface of the porous plate 20b is defined by the length from the bottom surface of the right cone passing through the end _20c1 to the center _20c2 corresponding to the apex of the right cone.

After conveying the work 11 to the chuck table 20, the first surface 11a side of the work 11 is sucked and held by the holding surface 20c of the chuck table (second holding table) 20 so that the second surface 11b of the work 11 is exposed. (Second holding step (S50)) (see FIG. 3).

FIG. 3 is a partial cross-sectional side view showing the second holding step (S50). In the second holding step (S50), the workpiece 11 is elastically deformed so as to correspond to the shape of the holding surface 20c. Then, the tilt adjusting mechanism 10 is operated to adjust the tilt of the rotary shaft 20d of the chuck table 20. FIG.

Specifically, when the grinding surface 18e is brought into contact with the work 11, a portion 20e of the holding surface 20c located below the contact area between the grinding wheel 18c and the work 11 becomes parallel to the grinding surface 18e. Similarly, the inclination of the rotating shaft 20d is adjusted. At this time, as shown in FIG. 3, a straight line 20f extending from the portion 20e of the holding surface 20c and the grinding surface 18e are parallel.

After the second holding step (S50), the inclination of the rotation axis 20d of the chuck table 20 is maintained, and the chuck table 20 and the grinding wheel 18 are rotated in a predetermined direction. In this state, the grinding unit 12 is moved downward at a grinding feed rate of 1 μm/s, for example, and the grinding wheel 18 c is pressed against the workpiece 11 .

Thereby, the second surface 11b side of the workpiece 11 is ground (second grinding step (S60)). In the second grinding step (S60) of this embodiment, the workpiece 11 is ground until the thickness reaches 2.3 mm. FIG. 4A is a partial cross-sectional side view showing the second grinding step (S60), and FIG. 4B is a cross-sectional view of the workpiece 11 after the second grinding step (S60). FIG. 5 is a flowchart showing the grinding method of the first embodiment.

In the second grinding step (S60), the first surface 11a side of the workpiece 11 whose warp has been reduced is held by the holding surface 20c, and the second surface 11b side of the workpiece 11 is held with the first surface 11a as a reference. It can be ground evenly. Therefore, the workpiece 11 can be thinned to a constant finished thickness, and the second surface 11b side of the workpiece 11 can be made substantially flat with reduced warpage.

In addition, in the second grinding step (S60), while the workpiece 11 is held so that the outer peripheral portion on the second surface 11b side protrudes higher than the central portion, the second surface 11b side of the workpiece 11 is held. to grind.

Therefore, the grinding wheel 18c can easily bite into the outer peripheral portion of the second surface 11b, compared to the case of grinding the second surface 11b side substantially parallel to the grinding surface 18e. That is, in the second grinding step (S60), it is advantageous that the grinding wheel 18c is less likely to slip on the second surface 11b side.

The workpiece 11 in which the warp is reduced compared to before grinding and both the first surface 11a and the second surface 11b are processed to be substantially flat can be used, for example, as a porous plate of a chuck table of a cutting device (that is, a dicer). used.

Next, a grinding method according to the second embodiment will be described. In the first grinding step (S30) of the above-described first embodiment, the chuck table 6 having a planar holding surface 6c is used, and in the second grinding step (S60), a chuck having a convex holding surface 20c is used. Table 20 was used. That is, different chuck tables were used in the first grinding step (S30) and the second grinding step (S60).

In contrast, in the second embodiment, the holding surfaces of the chuck table used in the first grinding step (S30) and the second grinding step (S60) are both planar. That is, in the second embodiment, the same chuck table 6 is used in the first grinding step (S30) and the second grinding step (S60). Thereby, grinding can be completed using one chuck table 6 .

A holding surface 6c of the chuck table 6 has a planar shape. That is, the holding surface 6c is a substantially flat surface in which the central portion does not protrude from the outer peripheral portion as compared with the holding surface 20c of the chuck table 20. As shown in FIG. Since pores are exposed on the holding surface 6c, the holding surface 6c is not a completely flat surface.

However, since the aggregates exposed on the holding surface 6c are subjected to grinding or the like and the aggregates are processed so that the heights of the aggregates are substantially uniform, the holding surface 6c (that is, the upper surface of the porous plate 6b) is It can be regarded as substantially flat. The bottom surface of the porous plate 6b also has the same flatness as the top surface.

Next, a method for grinding the workpiece 11 according to the second embodiment will be described. Since the steps from the first attaching step (S10) to the protective member peeling step (S40) are the same as those of the grinding method according to the first embodiment, description thereof will be omitted.

After the protective member peeling step (S40), the holding surface 6c sucks and holds the first surface 11a side through the protective tape 13b (second holding step (S50)) (see FIG. 6A). . Since the first surface 11a side of the work 11 is flattened by the first grinding step (S30), the work 11 hardly deforms even if it is held by the holding surface 6c.

In the second holding step (S50), the rotating shaft 14b of the spindle and the rotating shaft 6d of the chuck table 6 are made parallel. That is, the inclination of the rotating shaft 6d is adjusted so that the grinding surface 18e and the rotating shaft 6d are orthogonal.

After the second holding step (S50), the chuck table 6 and the grinding wheel 18 are rotated in a predetermined direction, and the grinding unit 12 is moved downward at a grinding feed rate of, for example, 1 μm/s to grind. The grindstone 18c is pressed against the workpiece 11. - 特許庁

Thereby, the second surface 11b side of the workpiece 11 is ground (second grinding step (S60)). FIG. 6A is a partial cross-sectional side view showing a second grinding step (S60) according to the second embodiment, and FIG. 6B is a second grinding step according to the second embodiment. FIG. 11 is a cross-sectional view of the workpiece 11 after step (S60);

Also in the second grinding step (S60) of the second embodiment, the second surface 11b side of the workpiece 11 is uniformly ground while the first surface 11a of the workpiece 11 whose warpage is reduced is held by the holding surface 6c. Grind. At this time, since the substantially flat first surface 11a serves as a reference in the thickness direction of the work 11, the work 11 is thinned to a constant finished thickness, and the warp of the work 11 on the second surface 11b side is also reduced. can be reduced.

In addition, in the second grinding step (S60) of the second embodiment, the workpiece 11 is held in such a manner that the outer peripheral portion on the second surface 11b side protrudes upward compared to the central portion, and the workpiece is The second surface 11b side of 11 is ground.

Therefore, the grinding wheel 18c can easily bite into the outer peripheral portion of the second surface 11b, compared to the case of grinding the second surface 11b side substantially parallel to the grinding surface 18e. That is, in the second grinding step (S60), it is advantageous that the grinding wheel 18c is less likely to slip on the second surface 11b side.

Next, a third embodiment will be described. The holding surfaces of the chuck table used in the first grinding step (S30) and the second grinding step (S60) in the third embodiment are both convex. That is, in the third embodiment, the same chuck table 20 is used in the first grinding step (S30) and the second grinding step (S60). Thereby, the grinding process can be completed using one chuck table 20 .

Next, a method for grinding the workpiece 11 according to the third embodiment will be described. Since the first attaching step (S10) is the same as the grinding method according to the first embodiment, the description is omitted. After the first attaching step (S10), the second surface 11b side is held by suction with the holding surface 20c via the protective tape 13b (first holding step (S20)) (see FIG. 7).

The protrusion amount C of the holding surface 20c of the chuck table 20 used in the first holding step (S20) is set to be smaller than the warp amount A of the workpiece 11. FIG. Therefore, even if the protective tape 13a is held by the holding surface 20c, the closed space 15 is formed by the workpiece 11 and the protective tape 13a.

In the first holding step (S20), the rotating shaft 14b of the spindle and the rotating shaft 20d of the chuck table 20 are made parallel. That is, the inclination of the rotating shaft 20d is adjusted so that the grinding surface 18e and the rotating shaft 20d are perpendicular to each other. As a result, the plane formed by the outer peripheral edge of the chuck table 20 during rotation of the chuck table 20 and the grinding surface 18e are positioned parallel to each other.

After the first holding step (S10), the chuck table 20 and the grinding wheel 18 are rotated in a predetermined direction, and the grinding unit 12 is moved downward at a grinding feed rate of, for example, 1 μm/s to grind. The grindstone 18c is pressed against the workpiece 11. - 特許庁

Thereby, the first surface 11a side of the workpiece 11 is ground (first grinding step (S30)). FIG. 7 is a partial cross-sectional side view showing the first grinding step (S30) according to the third embodiment.

Also in the first grinding step (S30) of the third embodiment, the shape of the space 15 closed by the work 11 and the protective tape 13a is maintained, and the first surface 11a side is ground while the work 11 is not deformed. . As a result, as shown in FIG. 2B, the first surface 11a of the workpiece 11 after grinding can be made substantially flat with reduced warpage.

Next, after the protective tape 13b made of resin is attached to the entire first surface 11a side ground in the first grinding step (S30), the protective tape 13a is peeled off from the first surface 11a side of the workpiece 11. (Protective member stripping step (S40)).

After the protective member peeling step (S40), the holding surface 20c sucks and holds the first surface 11a through the protective tape 13b (second holding step (S50)). In the second holding step (S50), the workpiece 11 is elastically deformed so as to follow the convex shape of the holding surface 20c (see FIG. 3).

In addition, in the second holding step (S50), the tilt adjusting mechanism 10 is operated to adjust the tilt of the rotary shaft 20d of the chuck table 20. FIG. Specifically, when the grinding surface 18e is brought into contact with the workpiece 11, a portion 20e of the holding surface 20c located below the contact area between the grinding wheel 18c and the workpiece 11 is The inclination of the rotating shaft 20d is adjusted so that it becomes parallel to .

After the second holding step (S50), the chuck table 20 and the grinding wheel 18 are rotated in a predetermined direction, and the grinding unit 12 is moved downward at a grinding feed rate of, for example, 1 μm/s to grind. The grindstone 18c is pressed against the workpiece 11. - 特許庁Thereby, as shown in FIG. 4A, the second surface 11b side of the workpiece 11 is ground (second grinding step (S60)).

Also in the second grinding step (S60) of the third embodiment, the second surface 11b side of the workpiece 11 is uniformly ground while the first surface 11a of the workpiece 11 whose warpage is reduced is held by the holding surface 20c. Grind. At this time, since the substantially flat first surface 11a serves as a reference in the thickness direction of the work 11, the work 11 is thinned to a constant finished thickness, and the warp of the work 11 on the second surface 11b side is also reduced. can be reduced.

In addition, in the second grinding step (S60) of the third embodiment, the workpiece 11 is held in such a manner that the outer peripheral portion on the second surface 11b side protrudes upward compared to the central portion, and the workpiece is The second surface 11b side of 11 is ground.

Therefore, the grinding wheel 18c can easily bite into the outer peripheral portion of the second surface 11b, compared to the case of grinding the second surface 11b side substantially parallel to the grinding surface 18e. That is, in the second grinding step (S60), it is advantageous that the grinding wheel 18c is less likely to slip on the second surface 11b side.

In addition, the structures, methods, and the like according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. As an example, the chuck tables 6 and 20 may be provided in one grinding device.

After the first grinding step (S30) is performed using the chuck table 20 as shown in FIG. 7, the second grinding step (S60) is performed using the chuck table 6 as shown in FIG. good too.

Furthermore, the workpiece 11 may be a warped semiconductor wafer. In this case, after peeling the protective tape 13a in the protective member peeling step (S40), the second holding step (S50) and the second grinding step (S60) are performed without attaching the protective tape 13b to the first surface 11a. may be performed.

2 grinding device 4 grinding device 6 chuck table 6a frame 6b porous plate 6c holding surface 6d rotating shaft 8 table base 10 tilt adjusting mechanism 10a fixed support member 10b movable supporting member 12 grinding unit 14a spindle housing 14b rotating shaft 16 wheel mount 18 grinding wheel 18a wheel base 18b lower surface (one surface)
18c grinding wheel 18d lower surface 18e grinding surface 20 chuck table 20a frame 20b porous plate 20c holding surface 20c _one end,
20c ₂ center 20d rotation axis 20e part 20f straight line 11 workpiece 11a first surface 11b second surface 13a protective tape (first protective member)
13b protective tape (second protective member)
15 Space A Amount of warp B Plane C Amount of protrusion

Claims (4)

A grinding unit for grinding a convex first surface and a concave second surface of a warped plate-shaped workpiece, and having an annular wheel base and a grindstone portion annularly arranged on one side of the wheel base. A grinding method for grinding with
a first attachment of attaching a first protective member to the outer peripheral portion of the second surface of the work to form a closed space between the second surface side of the work and the first protective member; a step;
a first holding step of sucking and holding the first protection member with the holding surface of the disk-shaped first holding table in the state where the space is formed;
a first grinding step of grinding the first surface side of the work in a state in which the rotation axis of the first holding table and the rotation axis of the grinding unit are parallel and the space is formed;
After the first grinding step, a protective member stripping step of stripping the first protective member from the workpiece;
a second holding step of sucking and holding the first surface side of the work with the holding surface of a disk-shaped second holding table so that the second surface is exposed after the protective member peeling step; ,
a second grinding step of grinding the second surface side of the workpiece held by the holding surface of the second holding table with the grinding unit ;
A grinding method, wherein the workpiece is a porous plate formed through compression molding and firing of ceramic particles, and the first protective member is a protective tape. 2. The grinding method according to claim 1, wherein the first holding table and the second holding table are the same table. The holding surface of the first holding table has a planar shape,
The holding surface of the second holding table is formed to have a convex shape as it goes from the outer peripheral portion to the central portion,
In the second grinding step, a portion of the holding surface of the second holding table located below the contact area between the grindstone portion and the workpiece is parallel to the grinding surface defined by the lower surface of the grindstone portion. 2. The grinding method according to claim 1, wherein the workpiece is ground by the grinding unit while the rotating shaft of the second holding table is tilted so as to be . In the protective member peeling step, a second protective member is attached to the first surface ground in the first grinding step, and then the first protective member is peeled off from the workpiece. The grinding method according to any one of claims 1 to 3.

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