TW202319181A - Grinding method and grinding apparatus for workpiece capable of suppressing occurrence of machining defects - Google Patents

Abstract

The present invention provides a grinding method for workpiece capable of suppressing the occurrence of machining defects. The grinding method for workpiece of the present invention utilizes a grinding apparatus to grind the workpiece, wherein the grinding apparatus comprises a holding workbench for holding workpiece by a holding plane; and, a grinding unit for grinding the workpiece held by the holding workbench by a grinding wheel having a plurality of grinding stones arranged as a ring shape. The grinding method for workpiece includes the following steps: a groove forming step for enabling the grinding stones contacting the workpiece and grinding the workpiece while not rotating the holding workbench but rotating the grinding wheel, and forming an arc-shaped groove on the workpiece with an depth not reaching the thickness of finished product; and, a grinding step for enabling the grinding stones contacting the surface of the workpiece formed with a groove while keeping the holding workbench and the grinding wheel rotating, and grinding the workpiece until the thickness of the workpiece becomes the thickness of the finished product.

Description

Grinding method and grinding device for workpiece

The invention relates to a grinding method for a processed object and a grinding device for grinding the processed object.

In the manufacturing steps of device wafers, the following wafers can be used: IC (Integrated Circuit), LSI ( Large-scale integrated circuits, Large Scale Integration) and other devices. A plurality of device wafers each having a device can be manufactured by dividing the wafer along planned dividing lines. Device chips can be mounted on various electronic devices such as mobile phones and personal computers.

In recent years, along with miniaturization of electronic devices, there has been an increasing demand for thinner device wafers. Then, a method of performing grinding on a wafer before division to thin the wafer has been used. A grinding apparatus including a holding table for holding the wafer and a grinding unit for grinding the wafer may be used for grinding the wafer.

A grinding wheel having a plurality of grinding stones arranged in a ring shape is installed in the grinding unit of the grinding device. Grinding stones are formed by fixing abrasive grains made of diamond or the like with a binder (bonding material). With the wafer held by the holding table, the wafer can be ground by bringing the grinding stone into contact with the wafer while rotating the holding table and the grinding wheel (see Patent Document 1). prior art literature patent documents

Patent Document 1: Japanese Unexamined Patent Publication No. 2009-90389

The problem to be solved by the invention

In the grinding process, the workpiece can be processed by bringing the abrasive grains protruding from the bond material of the grinding stone into contact with the workpiece. Therefore, in grinding a workpiece, it is desirable to maintain a state where the abrasive grains protrude from the bonding material moderately.

When the grinding stone collides with the workpiece, the abrasive grains will gradually fall off from the bond material. However, if the grinding process is continued after the abrasive grains fall off, a phenomenon called self-edging occurs: new abrasive grains are exposed from the bonding material due to contact and abrasion between the bonding material and the workpiece. With this self-generating edge, the state in which the abrasive grains protrude from the bond can be maintained, and the reduction in the grinding ability of the grinding stone can be prevented.

However, depending on the material of the workpiece or the state of the ground surface of the workpiece, the timing at which abrasive grains fall off may be advanced. For example, when a thin film such as an oxide film is formed on the ground surface of the workpiece, abrasive grains are captured by the thin film, and the abrasive grains tend to fall off. In such a case, the period from the time when the abrasive grains fall off to the completion of the spontaneous cutting edge, that is, the period during which the workpiece is ground in a state where the grinding ability of the grinding stone becomes low, becomes easy to The workpiece has poor processing.

The present invention was made in view of the above problems, and an object of the present invention is to provide a grinding method and a grinding device for a workpiece that can suppress occurrence of machining defects. means to solve problems

According to one aspect of the present invention, there is provided a method for grinding a workpiece, which uses a grinding device to grind the workpiece. The grinding device includes: a holding table for holding the workpiece on a holding surface and a grinding unit for grinding the workpiece held by the holding table with a grinding wheel having a plurality of grinding stones arranged in a ring shape, The grinding method of the aforementioned workpiece has the following steps: In the step of forming a groove, the workpiece is ground by bringing the grinding stone into contact with the workpiece while the grinding wheel is rotated without rotating the holding table. The material forms arc-shaped grooves that do not reach the depth of the finished product thickness; and A grinding step of bringing the grinding stone into contact with the surface side of the workpiece on which the groove is formed while the holding table and the grinding wheel are rotated, and grinding the workpiece Until the thickness of the workpiece becomes the thickness of the finished product.

Furthermore, it is preferable that in the groove forming step, the angle in the rotation direction of the holding table is set to a predetermined angle. Also, it is preferable that in the groove forming step, the workpieces are individually ground at different angles in the rotation direction of the holding table to form a plurality of grooves in the workpiece.

In addition, according to another aspect of the present invention, there is provided a grinding device comprising: a holding table for holding a workpiece on a holding surface; and a grinding unit having a plurality of A grinding wheel for grinding the grinding stone is used to grind the workpiece held by the holding table; the grinding feeding unit is made to make the holding table and the grinding unit face each other in a direction perpendicular to the holding surface. and a control unit that controls the holding table, the grinding unit and the grinding feed unit, The control unit can switch between the first mode and the second mode. In the aforementioned first mode, the grinding wheel is rotated by the grinding feeding unit without rotating the holding table. The grinding stone is brought into contact with the workpiece to form a groove in the workpiece to a depth that does not reach the thickness of the finished product. In the second mode, the holding table and the grinding wheel are rotated. The grinding stone is brought into contact with the surface side of the workpiece on which the groove is formed by the grinding feed unit, whereby the workpiece is ground until the thickness of the workpiece becomes the thickness of the finished product.

Furthermore, preferably, the control unit can control the angle in the rotation direction of the holding table. Invention effect

In the method and apparatus for grinding a workpiece according to one aspect of the present invention, the grinding stone is brought into contact with the workpiece after the workpiece is formed with an arc-shaped groove whose depth does not reach the thickness of the finished product. Grinding the workpiece until the thickness of the workpiece reaches the thickness of the finished product. Thereby, when the workpiece is ground and thinned, the grinding stone collides with the groove to promote self-edging. As a result, the grinding ability of a grinding stone can be maintained, and the generation|occurrence|production of a processing defect can be suppressed.

form for carrying out the invention

Hereinafter, an embodiment of one aspect of the present invention will be described with reference to the attached drawings. First, a configuration example of a grinding device that can be used in the method of processing a workpiece according to this embodiment will be described. FIG. 1 is a perspective view showing a grinding device 2 . In addition, in FIG. 1 , the X-axis direction (left-right direction, first horizontal direction) and the Y-axis direction (front-back direction, second horizontal direction) are directions perpendicular to each other. In addition, the Z-axis direction (vertical direction, vertical direction, and height direction) is a direction perpendicular to the X-axis direction and the Y-axis direction.

The grinding device 2 is provided with a base 4 which supports and accommodates each component constituting the grinding device 2 . A rectangular opening 4a is provided on the upper surface side of the front end of the base 4, and a conveying unit (transporting mechanism) 6 is provided inside the opening 4a. 2. To process the processed object 11.

Cassette installation areas 8 a and 8 b are provided on both sides of the transport unit 6 . Cassettes 10a, 10b for accommodating workpieces 11 are provided in the cassette installation areas 8a, 8b, respectively. A plurality of predetermined workpieces 11 (processed objects 11 before processing) that can be processed by the grinding device 2 can be accommodated in the cassette 10a. On the other hand, a plurality of workpieces 11 processed by the grinding device 2 (processed workpieces 11 ) may be housed in the magazine 10b.

For example, the workpiece 11 is a silicon wafer formed in a disk shape, and has a front surface (first surface) 11a and a rear surface (second surface) 11b substantially parallel to each other. The workpiece 11 is partitioned into a plurality of rectangular regions by a plurality of planned dividing lines (cutting lines) arranged in a grid pattern so as to intersect each other. Furthermore, devices such as ICs and LSIs are respectively formed on the front surface 11a side of the region demarcated by the dividing line.

A plurality of device wafers each having a device can be manufactured by dividing the workpiece 11 along the planned dividing line. Also, if the workpiece 11 is ground and thinned by the grinding device 2 before the workpiece 11 is divided, a thinned device wafer can be obtained.

However, the type, material, size, shape, structure, etc. of the workpiece 11 are not limited. For example, the workpiece 11 can also be a semiconductor other than silicon (gallium arsenide (GaAs), indium phosphide (InP), gallium nitride (GaN), silicon carbide (SiC), etc.), glass, ceramics, resin, metal etc. constitute the substrate. Also, there are no restrictions on the type, number, shape, structure, size, arrangement, etc. of the devices formed on the workpiece 11 , and no devices may be formed on the workpiece 11 .

An alignment mechanism (calibration mechanism) 12 is provided obliquely behind the opening 4a. The workpiece 11 accommodated in the cassette 10 a can be transported to the alignment mechanism 12 by the transport unit 6 . Then, the alignment mechanism 12 aligns and arranges the workpiece 11 at a predetermined position.

At a position adjacent to the alignment mechanism 12, a conveyance unit (transportation mechanism, loading arm) 14 for conveying the workpiece 11 is provided. The transfer unit 14 includes a suction pad that sucks and holds the upper surface side of the workpiece 11 . Then, the conveying unit 14 holds the workpiece 11 aligned by the alignment mechanism 12 with the suction pad, and rotates the suction pad to convey the workpiece 11 backward.

A disk-shaped turntable 16 is provided behind the transfer unit 14 . A rotary drive source (not shown) such as a servo motor is connected to the turntable 16 , and the rotary drive source rotates the turntable 16 around a rotation axis substantially parallel to the Z-axis direction.

On the turntable 16, a plurality of holding tables (job tables) 18 for holding the workpiece 11 are provided. What is shown in FIG. 1 is an example in which three holding tables 18 are arranged at approximately equal intervals along the circumferential direction of the turntable 16 . The turntable 16 will rotate counterclockwise (the direction shown by the arrow α) in the perspective of the plane, and each holding table 18 will be transferred according to the transfer position A, the first grinding position (rough grinding position) B, the second grinding position Positioning in the order of cutting position (finish grinding position) C and transfer position A.

The rotation drive source 20 (refer FIG. 2) which rotates the holding table 18 is connected to each holding table 18. As shown in FIG. For example, the rotational drive source 20 may be a servo motor, and rotates the holding table 18 around a rotational axis substantially parallel to the Z-axis direction. In addition, the rotary drive source 20 is equipped with the detector (encoder) which detects the rotation angle of the output shaft of the rotary drive source 20 (rotation angle of the holding table 18).

The columnar support structure 22a is arrange|positioned behind the 1st grinding position B, and the columnar support structure 22b is arrange|positioned behind the 2nd grinding position C. As shown in FIG. A grinding feeding unit (moving unit, moving mechanism) 24a is provided on the front surface side of the support structure 22a, and a grinding feeding unit (moving unit, moving mechanism) 24b is provided on the front surface side of the supporting structure 22b.

Each of the grinding feed units 24a and 24b includes a pair of guide rails 26 arranged substantially parallel to the Z-axis direction. A plate-shaped moving plate 28 is attached to the pair of guide rails 26 in a slidable state along the guide rails 26 . A nut portion (not shown) is provided on the rear surface side (back side) of the moving plate 28 , and the ball screw 30 arranged substantially parallel to the guide rail 26 is screwed to the nut portion. In addition, a pulse motor 32 is connected to an end of the ball screw 30 . When the ball screw 30 is rotated by the pulse motor 32, the moving plate 28 moves along the Z-axis direction.

A grinding unit 34a for performing rough grinding of the workpiece 11 is fixed to the front surface side (front side) of the moving plate 28 included in the grinding feed unit 24a. On the other hand, a grinding unit 34b that performs finish grinding of the workpiece 11 is fixed to the front surface side (front side) of the moving plate 28 included in the grinding feed unit 24b. The grinding feeding units 24a, 24b make the holding table 18 and the grinding units 34a, 34b vertical to the holding surface 18a (see FIG. 2 ) of the holding table 18 by raising and lowering the grinding units 34a, 34b. The direction moves relative to each other.

The grinding units 34a and 34b each include a hollow cylindrical casing 36 . Inside the casing 36 is housed a cylindrical main shaft 38 (see FIG. 2 ) arranged along the Z-axis direction. The front end portion (lower end side) of the main shaft 38 is exposed from the housing 36 . Further, a rotational drive source 40 is connected to a base end portion (upper end side) of the main shaft 38 . For example, the rotational drive source 40 may be a servo motor, and rotates the main shaft 38 about a rotational axis substantially parallel to the Z-axis direction.

FIG. 2 is a front view showing the grinding device 2 . In FIG. 2, the holding table 18 and the grinding unit 34a which were arrange|positioned at the 1st grinding position B are shown in figure.

The upper surface of the holding table 18 constitutes a holding surface 18 a for holding the workpiece 11 . The holding surface 18 a is a flat surface substantially parallel to the X-axis direction and the Y-axis direction, and is formed in a circular shape corresponding to the shape of the workpiece 11 , for example. Moreover, the holding surface 18a is connected to a suction source (not shown) such as an injector through a flow path (not shown), a valve (not shown) and the like formed inside the holding table 18 . If the negative pressure of the suction source acts on the holding surface 18 a in the state where the workpiece 11 is arranged on the holding surface 18 a, the workpiece 11 can be sucked and held by the holding table 18 .

A disc-shaped mount 42 made of metal or the like is fixed to the lower end of the main shaft 38 of the grinding unit 34a. Furthermore, a grinding wheel 44a for rough grinding is attached to the lower surface side of the attachment seat 42 . The grinding wheel 44a rotates around a rotation axis substantially parallel to the Z-axis direction by the power transmitted from the rotation drive source 40 (see FIG. 1 ) through the spindle 38 and the mount 42 .

The grinding wheel 44 a includes an annular base 46 made of metal such as aluminum or stainless steel and formed to have substantially the same diameter as the mounting seat 42 . On the lower surface side of the base 46 , a plurality of rectangular parallelepiped grinding stones 48 are arranged in a ring shape along the circumferential direction of the base 46 . For example, the grinding stone 48 can be made by combining abrasive grains composed of diamond, cBN (cubic boron nitride, cubic boron nitride) and the like with metal bond, resin bond, vitrified bond, etc. fixed and formed. However, the material, shape, structure, size, etc. of the grinding stone 48 are not limited, and the number of grinding stones 48 included in the grinding wheel 44a may be set arbitrarily.

The grinding unit 34b shown in FIG. 1 is configured similarly to the grinding unit 34a. And the grinding wheel 44b for finishing grinding is attached to the lower surface side of the attachment seat 42 of the grinding unit 34b. The construction of the grinding wheel 44b will be the same as that of the grinding wheel 44a. However, the average particle size of the abrasive grains of the grinding stones 48 included in the grinding wheel 44b is smaller than the average particle size of the abrasive grains of the grinding stones 48 included in the grinding wheel 44a.

The grinding unit 34a grinds the workpiece 11 held by the holding table 18 positioned at the first grinding position B with the grinding wheel 44a. Thereby, rough grinding can be performed on the workpiece 11 . Moreover, the grinding unit 34b grinds the workpiece 11 held by the holding table 18 positioned at the second grinding position C with the grinding wheel 44b. Thereby, finish grinding can be performed on the workpiece 11 .

In addition, grinding fluid supply paths (not shown) for supplying liquid (grinding fluid) such as pure water are provided inside or near the grinding units 34a and 34b, respectively. When grinding the workpiece 11 , the grinding fluid can be supplied to the workpiece 11 and the grinding stone 48 .

In the vicinity of the holding table 18 positioned at the first grinding position B, and near the holding table 18 positioned at the second grinding position C, the workpiece held by the holding table 18 is measured. 11 thickness measuring device 50. The thickness measuring device 50 includes a height measuring device (height gauge) 52a for measuring the height of the upper surface of the workpiece 11 held by the holding table 18, and a height measuring device (height gauge) 52a for measuring the height of the upper surface of the holding table 18 (holding surface 18a). Altimeter (height gauge) 52b. And the thickness measuring device 50 calculates the thickness of the workpiece 11 from the difference of the values measured by the height measuring devices 52a and 52b.

At a position adjacent to the conveyance unit 14 in the X-axis direction, a conveyance unit (conveyance mechanism, unloading arm) 54 for conveying the workpiece 11 is provided. The transfer unit 54 includes a suction pad that sucks and holds the upper surface side of the workpiece 11 . Further, the transfer unit 54 holds the workpiece 11 held by the holding table 18 arranged at the transfer position A with the suction pad, and rotates the suction pad to convey the workpiece 11 forward.

A washing unit (cleaning mechanism) 56 is arranged on the front side of the conveying unit 54 , and the washing unit 56 cleans the workpiece 11 conveyed by the conveying unit 54 . The workpiece 11 cleaned by the cleaning unit 56 can be transported by the transport unit 6 and accommodated in the cassette 10b.

In addition, the grinding device 2 is equipped with components connected to the grinding device 2 (transfer unit 6, alignment mechanism 12, transfer unit 14, turntable 16, holding table 18, rotary drive source 20, grinding feed Units 24a, 24b, grinding units 34a, 34b, thickness measuring device 50, transport unit 54, cleaning unit 56, etc.) control unit (control unit) 58. The actions of the constituent elements of the grinding device 2 can be controlled by the control unit 58 .

For example, the control unit 58 can be constituted by a computer, and includes a processing unit and a memory unit, the aforementioned processing unit can perform operations such as calculations required for the operation of the grinding device 2, and the aforementioned memory unit can store and use Various types of information processed (data, programs, etc.). The processing unit includes a processor such as a CPU (Central Processing Unit, Central Processing Unit). Also, the memory unit includes various types of memory that function as a main memory device, an auxiliary memory device, and the like. The control unit 58 generates signals (control signals) for controlling the components of the grinding device 2 by executing the programs stored in the memory unit.

Next, a specific example of the grinding method of the workpiece which grinds the workpiece 11 using the grinding apparatus 2 will be described. In the following, as an example, a case will be described in which the back surface 11b side of the workpiece 11 is ground and the workpiece 11 is thinned until the thickness of the workpiece 11 reaches a predetermined thickness (finished product thickness).

First, the workpiece 11 to be ground by the grinding device 2 is accommodated in the cassette 10a, and the cassette 10a is set on the cassette installation area 8a. Then, the to-be-processed object 11 is taken out from the cassette 10a by the conveyance unit 6, and is conveyed to the alignment mechanism 12, and the alignment of the to-be-processed object 11 is performed by the alignment mechanism 12. FIG. After that, the workpiece 11 is transferred from the alignment mechanism 12 to the holding table 18 arranged at the transfer position A by the transfer unit 14 .

For example, as shown in FIG. 2 , the workpiece 11 is arranged on the holding table 18 so that the front 11 a side faces the holding surface 18 a and the back 11 b side is exposed upward. In this state, when the negative pressure of the suction source is applied to the holding surface 18a, the workpiece 11 can be sucked and held by the holding table 18. Furthermore, when a device is formed on the front surface 11 a side of the workpiece 11 , a protective tape for protecting the device may be pasted on the front surface 11 a side of the workpiece 11 in advance. In this case, the workpiece 11 is sucked and held by the holding table 18 through the protective tape.

Next, the turntable 16 is rotated to arrange the holding table 18 holding the workpiece 11 at the first grinding position B. As shown in FIG. Then, the workpiece 11 held by the holding table 18 is ground by the grinding unit 34a.

In this embodiment, first, the workpiece 11 is ground by the grinding unit 34a to form an arcuate groove on the workpiece 11 (groove forming step). FIG. 3(A) is a front view showing the grinding device 2 in the groove forming step.

In the groove forming step, first, the angle in the rotation direction of the holding table 18 is set to a predetermined angle (for example, an initial angle (0°)) by the rotation driving source 20 . Then, without rotating the holding table 18, the grinding wheel 44a is rotated at a predetermined number of rotations by the rotational drive source 40 (see FIG. 1 ). At this time, the grinding stone 48 of the grinding wheel 44 a rotates so as to pass a position overlapping the center of the workpiece 11 . Then, the grinding wheel 44a is lowered at a predetermined speed (grinding feed) by the grinding feeding unit 24a, and the rotating grinding stone 48 is brought into contact with the back surface 11b of the workpiece 11 (ground surface). )side.

When the grinding wheel 44 a is lowered while bringing the grinding stone 48 into contact with the back surface 11 b side of the workpiece 11 , the back surface 11 b side of the workpiece 11 is ground by the grinding stone 48 . In addition, the descending speed of the grinding wheel 44a is adjusted so that the grinding stone 48 can be pressed against the back surface 11b side of the workpiece 11 with an appropriate force.

FIG. 3(B) is a plan view showing the holding table 18 and the grinding wheel 44a in the groove forming step. When the workpiece 11 is ground by rotating the grinding wheel 44 a without rotating the holding table 18 , the workpiece 11 is ground along the orbit of the rotating grinding stone 48 . As a result, an arc-shaped groove 11c having the same width as the grinding stone 48 is formed on the back surface 11b side of the workpiece 11 .

Fig. 4(A) is a plan view showing the workpiece 11 in which the groove 11c is formed. The groove 11c is formed in an arc shape extending from one end of the workpiece 11 through the center to the other end. Then, when the amount of grinding of the workpiece 11 (the depth of the groove 11c) reaches a predetermined value, the grinding of the workpiece 11 by the grinding wheel 44a is stopped. In addition, the groove 11c is formed so that the depth may not reach the final thickness (finished product thickness) of the workpiece 11 ground in the grinding process mentioned later. For example, the depth of the groove 11c can be set such that the difference between the finished thickness of the workpiece 11 and the thickness of the groove 11c is 20 μm or more.

In the groove forming step, a plurality of workpieces 11 may be formed in the groove 11c. In this case, after the first groove 11c is formed, the rotation driving source 20 rotates the holding table 18 by a predetermined angle to change the angle in the rotation direction of the holding table 18 . Then, the workpiece 11 is ground by the grinding stone 48 to form a second arc-shaped groove 11 c on the back surface 11 b side of the workpiece 11 . Thereafter, the third and subsequent grooves 11c are formed in the same procedure.

Fig. 4(B) is a plan view showing the workpiece 11 in which a plurality of grooves 11c are formed. For example, after forming the first groove 11c, if the step of rotating the holding table 18 by 90° and grinding the workpiece 11 with the grinding stone 48 is repeated three times, the result will be as shown in FIG. 4(B) Four arc-shaped grooves 11 c are formed on the back surface 11 b side of the workpiece 11 . In this way, the plurality of grooves 11c can be formed on the workpiece 11 by grinding the workpiece 11 individually while keeping the angles in the rotation direction of the table 18 different.

Next, the workpiece 11 is ground until the thickness of the workpiece 11 becomes the finished thickness (grinding step). FIG. 5(A) is a front view showing the grinding device 2 in the grinding step.

In the grinding step, the holding table 18 is rotated at a predetermined number of rotations by the rotary driving source 20 (see FIG. 2 ), and the grinding wheel 44a is rotated at a predetermined rotation speed by the rotary driving source 40 (see FIG. 1 ). number of spins to spin. At this time, the grinding stone 48 of the grinding wheel 44 a rotates so as to pass a position overlapping the center of the workpiece 11 . Then, the grinding wheel 44a is lowered at a predetermined speed (grinding feed) by the grinding feeding unit 24a, and the rotating grinding stone 48 is brought into contact with the surface side of the workpiece 11 where the groove 11c is formed. (back side 11b side).

When the grinding wheel 44 a is lowered while bringing the grinding stone 48 into contact with the back surface 11 b side of the workpiece 11 , the back surface 11 b side of the workpiece 11 is ground by the grinding stone 48 . In addition, the descending speed of the grinding wheel 44a is adjusted so that the grinding stone 48 can be pressed against the back surface 11b side of the workpiece 11 with an appropriate force.

FIG. 5(B) is a plan view showing the holding table 18 and the grinding wheel 44a in the grinding step. When the holding table 18 and the grinding wheel 44 a are rotated to grind the workpiece 11 , the entire back surface 11 b side of the workpiece 11 is ground, and the workpiece 11 is thinned.

FIG. 6 is an enlarged cross-sectional view showing a part of the workpiece 11 ground by the grinding stone 48 . During the grinding of the workpiece 11 , the plurality of grinding stones 48 each come into contact with the workpiece 11 from the outer peripheral edge toward the center. In addition, when the rotating grinding stone 48 passes through the groove 11c, the lower surface side of the grinding stone 48 collides with the inner wall of the groove 11c, and abrasion of the bonding material of the grinding stone 48 is likely to occur. As a result, spontaneous sharpening of the abrasive grains embedded in the bonding material can be promoted and exposed from the bonding material, and a reduction in the grinding performance of the grinding stone 48 can be suppressed.

In particular, when a thin film such as an oxide film is formed on the rear surface 11 b side of the workpiece 11 , the grinding stone 48 is caught by the thin film and easily falls off from the bonding material. However, since the spontaneous cutting of the grinding stone 48 can be promoted by the groove 11c as described above, the grinding ability of the grinding stone 48 can be restored quickly.

When the workpiece 11 is ground until the thickness of the workpiece 11 reaches a predetermined thickness (finished product thickness), the grinding of the workpiece 11 by the grinding wheel 44a is stopped. Thereby, the rough grinding of the workpiece 11 is completed. FIG. 7 is a plan view showing the workpiece 11 after grinding. Grinding traces (saw marks) 11d radially formed from the center of the workpiece 11 toward the outer peripheral edge remain on the rear surface 11b side of the workpiece 11 after grinding. This grinding mark 11d is formed in a curved shape along the track of the rotating grinding stone 48 .

In addition, in the grinding of the workpiece 11 by the grinding wheel 44a, the thickness of the workpiece 11 can be measured by the thickness measuring device 50 (refer FIG. 1). Then, the timing at which the grinding of the workpiece 11 by the grinding unit 34 a is stopped can be controlled based on the thickness of the workpiece 11 measured by the thickness measuring device 50 .

Next, the turntable 16 is rotated to arrange the holding table 18 holding the workpiece 11 at the second grinding position C. Then, the workpiece 11 held by the holding table 18 positioned at the second grinding position C can be ground by the grinding unit 34b. Thereby, finish grinding of the workpiece 11 can be performed, and grinding marks 11d (see FIG. 7 ) formed on the back surface 11b side of the workpiece 11 can be removed.

The operations of the holding table 18 and the grinding unit 34b during finish grinding are the same as those of the holding table 18 and the grinding unit 34a during rough grinding. In addition, in the grinding of the workpiece 11 by the grinding wheel 44 b, the thickness of the workpiece 11 can be measured by the thickness measuring device 50 .

In addition, during finish grinding, the above-mentioned groove forming step and grinding step can also be implemented. Specifically, first, the grinding wheel 44 b is rotated without rotating the holding table 18 to bring the grinding stone 48 into contact with the workpiece 11 to form the groove 11 c on the back surface 11 b side of the workpiece 11 . (Refer to FIG. 3(A) and FIG. 3(B)). Thereafter, the grinding stone 48 is brought into contact with the workpiece 11 in a state in which the holding table 18 and the grinding wheel 44b are rotated, and the whole of the back surface 11b side of the workpiece 11 is ground (refer to FIG. ) and Figure 5(B)). Thereby, the self-generating edge of the grinding stone 48 can be promoted also when finishing grinding is performed on the workpiece 11 .

Next, the turntable 16 is rotated to arrange the holding table 18 holding the workpiece 11 at the transfer position A. As shown in FIG. Then, the processed workpiece 11 is transferred from the holding table 18 positioned at the transfer position A. As shown in FIG.

The workpiece 11 held by the holding table 18 positioned at the transfer position A can be transferred from the holding table 18 to the cleaning unit 56 by the transfer unit 54 and washed. Then, after cleaning by the cleaning unit 56 , the workpiece 11 is transported to the cassette 10 b by the transport unit 6 .

As described above, the grinding method of the workpiece of this embodiment includes: a groove forming step of forming an arc-shaped groove 11c on the workpiece 11 whose depth does not reach the thickness of the finished product; and a grinding step of grinding The grinding stone 48 comes into contact with the surface side of the workpiece 11 on which the groove 11c is formed, and grinds the workpiece 11 until the thickness of the workpiece 11 becomes the thickness of the finished product. Thereby, when the workpiece 11 is ground and thinned, the grinding stone 48 collides with the groove 11c to promote self-edging. As a result, the grinding ability of the grinding stone 48 can be maintained, and the occurrence of machining defects can be suppressed.

Furthermore, the operation of the grinding device 2 in the above-mentioned groove forming step and grinding step can be controlled by the control unit 58 . Specifically, in the groove forming step, the control unit 58 outputs a control signal to the rotary driving source 20 (see FIG. Keep the holding table 18 in a stopped state (non-rotating state). Moreover, the control unit 58 rotates the grinding wheel 44a at a predetermined number of rotations by outputting a control signal to the rotational drive source 40 of the grinding unit 34a.

Then, the control unit 58 outputs a control signal to the pulse motor 32 of the grinding feed unit 24a to rotate the ball screw 30 at a predetermined speed. Thereby, the grinding unit 34a descends at a predetermined speed, the grinding stone 48 comes into contact with the workpiece 11 , and the groove 11c is formed in the workpiece 11 . That is, the control unit 58 operates the grinding device 2 in the mode (first mode) for performing the groove forming step by outputting control signals to the constituent elements of the grinding device 2 .

On the other hand, in the grinding step, the control unit 58 rotates the holding table 18 at a predetermined number of rotations by outputting a control signal to the rotation drive source 20 (see FIG. 2 and the like). Moreover, the control unit 58 rotates the grinding wheel 44a at a predetermined number of rotations by outputting a control signal to the rotational drive source 40 of the grinding unit 34a.

Then, the control unit 58 outputs a control signal to the pulse motor 32 of the grinding feed unit 24a to rotate the ball screw 30 at a predetermined speed. Thereby, the grinding unit 34a descends at a predetermined speed, brings the grinding stone 48 into contact with the workpiece 11, and grinds the entire back surface 11b side of the workpiece 11. That is, the control unit 58 operates the grinding device 2 in a mode (second mode) for performing a grinding step by outputting a control signal to the constituent elements of the grinding device 2 .

As described above, after positioning the holding table 18 holding the workpiece 11 at the first grinding position B, the control unit 58 appropriately switches between the first mode and the second mode, thereby implementing the groove forming step and the second mode. Grinding step. In addition, the operation of the control unit 58 in the case where the groove forming step and the grinding step are implemented using the grinding unit 34b is also the same.

In the case of forming a plurality of grooves 11c in the groove forming step (refer to FIG. 4(B)), the control unit 58 keeps the table 18 at a predetermined position by outputting a control signal to the rotary drive source 20 (refer to FIG. 2 ). The interval angle (eg interval 90°) stops. Then, the workpiece 11 is ground by the grinding unit 34 a while maintaining the table 18 at a different angle, thereby forming the grooves 11 c.

In addition, the angle control of the holding table 18 by the control unit 58 can be implemented based on the signal input from the encoder with which the rotation drive source 20 is equipped. Specifically, the encoder detects the rotation angle of the output shaft of the rotary driving source 20 and outputs it to the control unit 58 . In addition, the control unit 58 calculates the amount of rotation of the output shaft of the rotary drive source 20 necessary to stop the holding table 18 at a desired angle based on the detection result of the encoder, and rotates the output shaft of the rotary drive source 20 The amount of rotation.

In addition, the structure, method, etc. of the above-mentioned embodiment can be implemented with a proper change as long as it does not deviate from the objective of this invention.

2: Grinding device 4,46: Abutment 4a: opening 6: Conveyor unit (conveyor mechanism) 8a, 8b: Cassette setting area 10a, 10b: Cassette 11: Processed object 11a: Front (Side 1) 11b: Back (side 2) 11c: ditch 11d: Grinding marks (saw marks) 12: Alignment mechanism (calibration mechanism) 14: Conveying unit (conveying mechanism, loading arm) 16: turntable 18: Hold the workbench (work clamping table) 18a: Keeping surface 20: Rotary drive source 22a, 22b: Support structure 24a, 24b: Grinding feed unit (moving unit, moving mechanism) 26: guide rail 28: Mobile board 30: Ball screw 32: Pulse motor 34a, 34b: grinding unit 36: Shell 38:Spindle 40: Rotary drive source 42: Mounting seat 44a, 44b: grinding wheel 48: Grinding whetstone 50:Thickness measuring device 52a, 52b: Altimeter (height gauge) 54: Conveying unit (conveying mechanism, unloading arm) 56: cleaning unit (cleaning mechanism) 58: Control unit (control unit) α: arrow A: Transfer location B: 1st grinding position (rough grinding position) C: The second grinding position (fine grinding position) X, Y, Z: direction

Fig. 1 is a perspective view showing a grinding device. Fig. 2 is a front view showing the grinding device. FIG. 3(A) is a front view showing the grinding device in the groove forming step, and FIG. 3(B) is a plan view showing the holding table and the grinding wheel in the groove forming step. FIG. 4(A) is a plan view showing a workpiece formed with grooves, and FIG. 4(B) is a plan view showing a workpiece formed with a plurality of grooves. FIG. 5(A) is a front view showing the grinding device in the grinding step, and FIG. 5(B) is a plan view showing the holding table and the grinding wheel in the grinding step. Fig. 6 is an enlarged cross-sectional view showing a part of a workpiece to be ground by a grinding stone. Fig. 7 is a plan view showing a workpiece after grinding.

2: Grinding device

11: Processed object

11a: Front (Side 1)

11b: Back (side 2)

11c: ditch

18: Hold the workbench (work clamping table)

18a: Keeping surface

20: Rotary drive source

34a: Grinding unit

38:Spindle

42: Mounting seat

44a: Grinding wheel

46: Abutment

48: Grinding whetstone

Claims (5)

A grinding method of a processed object is to use a grinding device to grind the processed object. The aforementioned grinding device has: holding the workbench to hold the workpiece on the holding surface; and a grinding unit for grinding the workpiece held by the holding table with a grinding wheel having a plurality of grinding stones arranged in a ring shape, The grinding method of the aforementioned workpiece is characterized by the following steps: In the step of forming a groove, the workpiece is ground by bringing the grinding stone into contact with the workpiece while the grinding wheel is rotated without rotating the holding table. The material forms arc-shaped grooves that do not reach the depth of the finished product thickness; and A grinding step of bringing the grinding stone into contact with the surface side of the workpiece on which the groove is formed while the holding table and the grinding wheel are rotated, and grinding the workpiece Until the thickness of the workpiece becomes the thickness of the finished product. The grinding method of a workpiece according to claim 1, wherein in the groove forming step, the angle in the rotation direction of the holding table is set to a predetermined angle. The grinding method of a workpiece according to claim 1 or 2, wherein in the groove forming step, the workpieces are ground at different angles in the rotation direction of the holding table, and the workpieces are ground in the groove forming step. The processed product forms a plurality of these grooves. A grinding device comprising: Keep the workbench to keep the surface to keep the workpiece; a grinding unit for grinding the workpiece held by the holding table with a grinding wheel having a plurality of grinding stones arranged in a ring shape; a grinding feed unit for relatively moving the holding table and the grinding unit along a direction perpendicular to the holding surface; and a control unit controlling the holding table, the grinding unit and the grinding feed unit, The aforementioned grinding device is characterized in that: the control unit can switch between the first mode and the second mode, and the aforementioned first mode is in the state where the holding table is not rotated and the grinding wheel is rotated, by means of the The grinding feed unit brings the grinding stone into contact with the workpiece, thereby forming a groove in the workpiece to a depth that does not reach the thickness of the finished product. The aforementioned second mode is when the holding table and the grinding In a state where the cutting wheel is rotating, the grinding stone is brought into contact with the surface side of the workpiece on which the groove is formed by the grinding feed unit, whereby the workpiece is ground to the workpiece The thickness becomes the thickness of the finished product. The grinding device according to claim 4, wherein the control unit can control the angle in the rotation direction of the holding table.

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