JP2023000134A - Grinding device - Google Patents

Abstract

To provide a novel grinding device capable of efficiently grinding plate-like workpiece likely bent greatly.SOLUTION: This grinding device comprises a control unit that controls a conveyance mechanism, a bending amount measurement instrument, and a correction unit. The control unit has a storage unit that stores a first threshold value for defining a range of bending amounts, and a determination unit that compares the bending amount of workpiece measured by the bending amount measurement instrument with the first threshold value stored in the storage unit to determine whether the workpiece can be held on a chuck table. When the determination unit determines that the workpiece can be held on the chuck table after measurement of the bending amount of the workpiece by the bending amount measurement instrument, the workpiece is conveyed to the chuck table by the conveyance mechanism. When the determination unit determines that the workpiece cannot be held on the chuck table, the workpiece is corrected by the correction unit.SELECTED DRAWING: Figure 5

Description

TECHNICAL FIELD The present invention relates to a grinding apparatus used when grinding a plate-like workpiece.

A semiconductor chip (device chip) provided with a device represented by an integrated circuit is incorporated into various electronic devices in the form of a package device (package device chip) sealed with resin. For example, if a package substrate is manufactured by sealing a plurality of chips with resin, and the package substrate is cut along the dividing line (street) between adjacent chips, a plurality of package devices corresponding to each chip can be obtained. can get.

In recent years, for the purpose of further reducing the thickness and weight of package devices, the number of occasions for grinding (grinding) package substrates before cutting them along a dividing line has increased. Grinding equipment used for this grinding typically includes a chuck table that can hold a plate-shaped workpiece by suction under the action of negative pressure, and a spindle on which a grinding wheel containing a plurality of grinding wheels is mounted. , is equipped with

When the package substrate is ground by the grinding apparatus, for example, the package substrate is held on the chuck table by applying a negative pressure from the chuck table to the package substrate while the package substrate is placed on the chuck table. After that, the grinding wheel and the chuck table are mutually rotated to press the grinding wheel against the exposed surface of the package substrate, thereby grinding and thinning the package substrate (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2002-200545

By the way, since the resin used for chip sealing shrinks when it is cured, the package substrate may warp greatly due to the stress caused by the shrinkage of the resin. If the package substrate warps significantly, a gap is generated between the outer edge of the package substrate and the chuck table. Even if negative pressure is applied to the package substrate from the chuck table, the negative pressure leaks through the gap and the package substrate cannot be properly held. Gone.

When the chuck table holds the workpiece, the grinding apparatus notifies the operator of the above-described problem. Upon receiving this notification, the operator collects the workpiece on the chuck table so that the chuck table can hold the next workpiece. However, when such work occurs, the workpiece cannot be ground efficiently.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and its object is to provide a new grinding apparatus capable of efficiently grinding a plate-like workpiece that may be greatly warped. be.

According to one aspect of the present invention, there is provided a chuck table having a holding surface for sucking and holding a plate-shaped workpiece, and a spindle to which a grinding wheel including a plurality of grinding wheels is mounted. A grinding unit for grinding the held workpiece with the grinding wheel, a cassette mounting table on which a cassette capable of accommodating a plurality of the workpieces is mounted, and the workpiece accommodated in the cassette. A conveying mechanism for conveying to a chuck table, a warp amount measuring device for measuring the warp amount of the workpiece, a straightening unit for correcting the warped workpiece, the conveying mechanism and the warp amount measuring device and a control unit for controlling the correction unit, wherein the control unit includes a storage section in which a first threshold value defining the range of the amount of warpage is stored; a determination unit that compares the warp amount of the workpiece with the first threshold value stored in the storage unit and determines whether or not the chuck table can hold the workpiece. After the amount of warpage of the workpiece is measured by the warp amount measuring device, when the determination unit determines that the workpiece can be held by the chuck table, the workpiece is transported. A grinding apparatus is provided in which a mechanism transports a workpiece to the chuck table, and the workpiece is corrected by the correction unit when the determination unit determines that the workpiece cannot be held by the chuck table.

Preferably, the correction unit includes a mounting section having a mounting surface on which the workpiece is mounted, and the mounting section disposed on the mounting surface side of the mounting section and mounted on the mounting surface. a pressing portion that applies force to the workpiece from the side opposite to the mounting surface. Moreover, preferably, a heater is provided in one or both of the placing portion and the pressing portion.

Preferably, the correction unit is disposed between the mounting portion and the pressing portion, and includes a mounting portion side contact surface that contacts the workpiece on the mounting portion side, and a contact surface on the side of the mounting portion that contacts the workpiece. and a pressing portion-side contact surface that contacts the other workpiece. Moreover, preferably, a heater is provided in the intervening portion.

Preferably, the apparatus further comprises a temporary storage cassette mounting table on which temporary storage cassettes that can temporarily store a plurality of workpieces that are determined to be unholdable by the chuck table are placed, and the control unit comprises: When the determination unit determines that the workpiece cannot be held by the chuck table, the workpiece is stored in the temporary storage cassette by the transport mechanism, and then the plurality of workpieces stored in the temporary storage cassette are stored. The workpiece is straightened at once by the straightening unit.

Preferably, the storage unit further stores a second threshold that defines a plurality of categories of the amount of warpage that cannot be held by the chuck table, and the determination unit measures The amount of warpage of the workpiece that has been obtained is compared with the second threshold value stored in the storage unit, and the workpiece that is determined to be unable to be held by the chuck table is one of the plurality of sections. The control unit further determines which one belongs to, and corrects the plurality of workpieces stored in the temporary storage cassette by the straightening unit for each section.

Preferably, the control unit, after straightening the workpiece with the straightening unit, measures the amount of warpage of the straightened workpiece again with the warp amount measuring device.

A grinding apparatus according to one aspect of the present invention includes a conveying mechanism that conveys a workpiece accommodated in a cassette to a chuck table, a warpage amount measuring device that measures the amount of warpage of the workpiece, and a warped workpiece. A straightening unit for straightening a workpiece and a control unit are provided. In addition, the control unit includes a storage unit that stores a first threshold value that defines the range of the amount of warpage, and the amount of warp of the workpiece measured by the warp amount measuring device and the first a determination unit that compares with a threshold value and determines whether or not the workpiece can be held by the chuck table.

Then, the control unit transports the workpiece to the chuck table by the transport mechanism only when the determination unit determines that the chuck table can hold the workpiece. Therefore, by simply storing an appropriate first threshold value in the storage unit, problems due to warpage when the workpiece is held by the chuck table do not occur. In other words, according to the grinding apparatus according to one aspect of the present invention, the efficiency of grinding the workpiece is not lowered due to a problem in holding the workpiece with the chuck table.

Further, the control unit corrects the workpiece with the correction unit when the determination unit determines that the chuck table cannot hold the workpiece. Therefore, it is not necessary for the operator to correct the workpiece using another device or the like so that the workpiece can be properly held by the chuck table. In other words, the work load of the operator can be reduced, and the efficiency of grinding the workpiece can be improved.

Thus, according to the grinding apparatus according to one aspect of the present invention, it is possible to efficiently grind a plate-like workpiece that may be greatly warped.

FIG. 1 is a perspective view schematically showing a grinding device. FIG. 2 is a side view schematically showing how the warp amount of a workpiece is measured by a warp amount measuring device. FIG. 3 is a side view schematically showing the internal structure of the correction unit. FIG. 4 is a side view schematically showing how the workpiece is straightened by the straightening unit. FIG. 5 is a functional block diagram showing part of the functional structure of the control unit. FIG. 6 is a flowchart showing part of the flow of processing when grinding a workpiece. FIG. 7 is a flow chart showing another part of the flow of processing when grinding a workpiece.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing a grinding device 2 according to this embodiment. In addition, in FIG. 1, some elements constituting the grinding apparatus 2 are represented by functional blocks. Also, the X-axis direction (front-rear direction), the Y-axis direction (left-right direction), and the Z-axis direction (vertical direction) used in the following description are perpendicular to each other.

As shown in FIG. 1, the grinding machine 2 has a base 4 that supports various elements that make up the grinding machine 2 . On the front end side of the upper surface of the base 4, a recessed storage portion 4a with an open upper end is provided. The first transport mechanism 6 is accommodated. The first transport mechanism 6 is typically a robot arm having a plurality of joints, and can not only transport the workpiece 11 but also turn the workpiece 11 upside down.

The workpiece 11 is, for example, a disk-shaped package substrate formed by sealing a plurality of semiconductor chips (device chips) with resin. The workpiece 11 is partitioned into a plurality of small regions by a plurality of dividing lines (streets) that cross each other, and chips are arranged in each of the small regions. In addition, each chip is provided with a device represented by an integrated circuit (IC).

In this embodiment, the disk-shaped package substrate is used as the workpiece 11, but the material, shape, structure, size, etc. of the workpiece 11 are not limited. For example, a package substrate having rectangular upper and lower surfaces can be used as the workpiece 11 . Similarly, the workpiece 11 may be a substrate having any shape and made of a material such as a semiconductor such as silicon, ceramics, resin, or metal.

As shown in FIG. 1, in front of the accommodating portion 4a, a cassette mounting table 10a on which the cassette 8a is mounted, a cassette mounting table 10b on which the cassette 8b is mounted, and a cassette (temporary storage cassette) 8c are mounted. A cassette mounting table (temporary storage cassette mounting table) 10c is provided. Each of the cassettes 8 a , 8 b , 8 c has multiple shelves and can accommodate multiple workpieces 11 . For example, the cassette 8a accommodates the workpiece 11 after grinding, the cassette 8b accommodates the unground workpiece 11, and the cassette 8c accommodates the workpiece 11 having a large warp as will be described later. 11 is temporarily housed.

A position adjusting mechanism 12 for adjusting the position of the workpiece 11 is provided obliquely behind the accommodating portion 4a. The position adjustment mechanism 12 includes a disk-shaped position adjustment table 12a and a plurality of pins 12b arranged around the position adjustment table 12a. By moving the plurality of pins 12b along the radial direction of the position adjustment table 12a, for example, the center of the workpiece 11 carried out from the cassette 8b by the first transport mechanism 6 and placed on the position adjustment table 12a can be moved. are aligned in the X and Y directions.

A warp amount measuring device 14 capable of measuring the amount of warp of the workpiece 11 is provided near the position adjusting mechanism 12 . The warp amount measuring device 14 includes, for example, an arm 14a that rotates around the base end in a plane substantially parallel to the X-axis direction and the Y-axis direction, and a laser distance measuring device fixed to the tip end of the arm 14a. 14b and. The laser distance measuring device 14b is arranged in a region corresponding to directly above the workpiece 11 placed on the position adjustment table 12a.

FIG. 2 is a side view schematically showing how the warp amount of the workpiece 11 is measured by the warp amount measuring device 14. As shown in FIG. In addition, in FIG. 2, the cross section of the workpiece 11 is shown for convenience of explanation. As shown in FIG. 2, the warp amount measuring device 14 measures the distance to the upper surface 11a of the workpiece 11 by the laser distance measuring device 14b, changes the position of the laser distance measuring device 14b by rotating the arm 14a, is repeated continuously or intermittently, information about the height of the upper surface 11a of the workpiece 11 is acquired.

In the present embodiment, as shown in FIG. 2, the height h of the outer edge of the upper surface 11a of the workpiece 11 based on the height of the central portion of the upper surface 11a of the workpiece 11 is defined as the warp amount a of the workpiece 11. handled. That is, in the case of a so-called concave warp, in which the height of the central portion of the upper surface 11a is smaller than the height of the outer edge, the amount of warp a is positive, and the height of the central portion of the upper surface 11a is lower than the height of the outer edge. In the case of a so-called center-convex warp that is greater than the height of , the amount of warp a is negative.

However, the positive/negative relation of the warpage amount a may be exchanged. That is, the height of the central portion of the upper surface 11a of the workpiece 11 based on the height of the outer edge of the upper surface 11a of the workpiece 11 may be treated as the warp amount a of the workpiece 11 . If the shape of the workpiece is not disk-shaped (for example, if the top or bottom surface is rectangular), it is possible to obtain a different value of the amount of warpage a depending on how the outer edge is selected for measurement. have a nature. In such a case, the outer edge portion to be measured should be selected so that the absolute value of the warp amount a obtained is as large as possible.

As shown in FIG. 1, on the side of the position adjusting mechanism 12 and the warp amount measuring device 14, a second conveying mechanism 16 is provided for holding the workpiece 11 and conveying it rearward. The second transport mechanism 16 includes, for example, an arm and a holding pad connected to the tip of the arm and capable of holding the upper surface of the workpiece 11 by suction. , the workpiece 11 whose position has been adjusted by the position adjusting mechanism 12 is conveyed backward.

A turntable 18 is provided behind the second transport mechanism 16 . The turntable 18 is connected to a rotary drive source (not shown) such as a motor, and rotates around a rotation axis generally parallel to the Z-axis direction. On the upper surface of the turntable 18, three chuck tables 20 used for holding the workpiece 11 are provided at approximately equal angular intervals. The number of chuck tables 20 provided on the turntable 18 is not limited.

The turntable 18 rotates, for example, in the direction indicated by the arrow in FIG. The finish grinding area C on the side of the grinding area B is moved in order. The second transport mechanism 16 transports the workpiece 11 held by the holding pad from the position adjusting table 12 a of the position adjusting mechanism 12 to the chuck table 20 arranged in the loading/unloading area A.

Each chuck table 20 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis substantially parallel to the Z-axis direction. A part of the upper end side of each chuck table 20 is made of, for example, a porous material, and the upper surface thereof serves as a holding surface 20a that holds the lower surface 11b side of the workpiece 11 . That is, each chuck table 20 has a holding surface 20a for holding the workpiece 11 on its top.

The holding surface 20 a is connected to a suction source (not shown) such as a vacuum pump through a suction path (not shown) formed inside the chuck table 20 . The workpiece 11 carried into the chuck table 20 is sucked on the lower surface 11b side by the negative pressure of the suction source acting on the holding surface 20a. Thus, the holding surface 20a holds the workpiece 11 by sucking the lower surface 11b side of the workpiece 11 .

As shown in FIG. 1, columnar support structures 22 are provided behind the rough grinding area B and the finish grinding area C (behind the turntable 18), respectively. A Z-axis movement mechanism 24 is provided on the front side of each support structure 22 . Each Z-axis moving mechanism 24 has a pair of guide rails 26 that are substantially parallel to the Z-axis direction, and a moving plate 28 is attached to the guide rails 26 in a slidable manner.

A nut (not shown) constituting a ball screw is fixed to the rear surface side (rear surface side) of each moving plate 28, and a screw shaft 30 substantially parallel to the guide rail 26 can rotate on this nut. connected in a manner. A motor 32 is connected to one end of the screw shaft 30 . By rotating the screw shaft 30 with the motor 32, the moving plate 28 moves along the guide rail 26 in the Z-axis direction.

A fixture 34 is provided on the front surface (surface) of each moving plate 28 . Each fixture 34 supports a grinding unit (processing unit) 36 for grinding (processing) the workpiece 11 . Each grinding unit 36 includes a spindle housing 38 secured to fixture 34 .

Each spindle housing 38 accommodates a spindle 40, which serves as a rotation axis substantially parallel to the Z-axis direction, in a rotatable manner. A lower end of each spindle 40 is exposed from the lower end surface of the spindle housing 38 . A disk-shaped mount 42 is fixed to the lower end of the spindle 40 .

A first grinding wheel 44a for rough grinding is attached to the lower surface of the mount 42 of the grinding unit 36 on the rough grinding area B side. The first grinding wheel 44a has a first wheel base made of metal such as stainless steel or aluminum and having approximately the same diameter as the mount 42 . On the lower surface of the first wheel base, a plurality of first grinding wheels are arranged in an annular shape, in which abrasive grains such as diamond suitable for rough grinding are fixed with a binder such as vitrified or resinoid.

The spindle housing 38 of the grinding unit 36 on the rough grinding area B side accommodates a first rotational drive source (not shown) such as a motor connected to the upper end side of the spindle 40 . The power of the first rotary drive source rotates the first grinding wheel 44a together with the spindle 40 .

Next to the first grinding wheel 44a, there is a liquid supply nozzle (not shown) capable of supplying a liquid (grinding liquid) such as pure water to a portion (processing point) where the workpiece 11 and the first grinding wheel come into contact with each other. is provided. However, instead of or together with the liquid supply nozzle, a liquid supply port used for supplying the liquid may be provided on the first grinding wheel 44a or the like.

A second grinding wheel 44b for finish grinding is attached to the lower surface of the mount 42 of the grinding unit 36 on the finish grinding area C side. The second grinding wheel 44b has a second wheel base made of metal such as stainless steel or aluminum and having approximately the same diameter as the mount 42 . On the lower surface of the second wheel base, a plurality of second grinding wheels are arranged in an annular shape, in which abrasive grains such as diamond suitable for finish grinding are fixed with a binder such as vitrified or resinoid.

The spindle housing 38 of the grinding unit 36 on the finish grinding area C side accommodates a second rotational drive source (not shown) such as a motor connected to the upper end side of the spindle 40 . The power of the second rotary drive source rotates the second grinding wheel 44b together with the spindle 40 .

Next to the second grinding wheel 44b, there is a liquid supply nozzle (not shown) capable of supplying a liquid (grinding liquid) such as pure water to a portion (processing point) where the workpiece 11 and the second grinding wheel come into contact. is provided. However, instead of or together with this liquid supply nozzle, a liquid supply port used for supplying liquid may be provided on the second grinding wheel 44b or the like.

The workpiece 11 held on each chuck table 20 is sequentially ground by the two sets of grinding units 36 described above. That is, the workpiece 11 held on the chuck table 20 in the rough grinding area B is ground by the grinding unit 36 on the rough grinding area B side, and the workpiece 11 held on the chuck table 20 in the finish grinding area C is ground. , is ground by the grinding unit 36 on the finish grinding area C side. The chuck table 20 in the finish grinding area C is again positioned in the loading/unloading area A after the grinding of the workpiece 11 is completed.

As shown in FIG. 1, at a position in front of the loading/unloading area A and on the side of the second transport mechanism 16,
A third transport mechanism 46 is provided to hold and forward the workpiece 11 after grinding. The third transport mechanism 46 includes a holding pad that sucks and holds the upper surface 11a side of the workpiece 11, and an arm connected to the holding pad. The workpiece 11 after grinding is conveyed forward from the chuck table 20 in the carry-in/carry-out area A. As shown in FIG.

A cleaning unit 48 that cleans the workpiece 11 carried out by the third transport mechanism 46 is provided in front of the third transport mechanism 46 . The cleaning unit 48 includes, for example, a spinner table that rotates while holding the lower surface 11b side of the workpiece 11, and a cleaning unit that injects a cleaning fluid onto the upper surface 11a side of the workpiece 11 held by the spinner table. a nozzle; The workpiece 11 cleaned by the cleaning unit 48 is transported by the first transport mechanism 6 and stored in, for example, a cassette 8a.

A straightening unit 50 for straightening the warped workpiece 11 is provided near the warp amount measuring device 14 . 3 is a side view schematically showing the internal structure of the straightening unit 50, and FIG. 4 is a side view schematically showing how the workpiece 11 is straightened by the straightening unit 50. As shown in FIG. 3 and 4 show a cross section of the workpiece 11 for convenience of explanation.

As shown in FIGS. 3 and 4, the correction unit 50 includes a correction table (mounting section) 52 large enough to support the entire workpiece 11 . The correction table 52 has, for example, a substantially flat upper surface (mounting surface) 52a, and the target workpiece 11 is mounted on this upper surface 52a.

Above the correction table 52, a plate-like pressing member (pressing portion) 54 is arranged to apply a downward force (pressure) to the workpiece 11 placed on the upper surface 52a. ing. The pressing member 54 has a substantially flat lower surface (pressing surface) 54a and is connected to an actuator (not shown). The actuator is typically a pneumatic cylinder, a hydraulic cylinder, or the like, and moves the pressing member 54 up and down.

Between the correction table 52 and the pressing member 54, a plurality (three in this embodiment) of plate-shaped intermediate plates (intervening portions) 56 are arranged. Each intermediate plate 56 has a substantially flat lower surface (mounting section side contact surface) 56a and a substantially flat upper surface (pressing section side contact surface) 56b, and is mounted on rails so as to be movable along the Z-axis direction. It is supported by a shaped support member (not shown).

It is desirable that each intermediate plate 56 is applied with an upward force by a biasing member such as a spring. Thereby, when no other force is applied to each intermediate plate 56, the distance between the straightening table 52 and the intermediate plate 56 and the distance between two adjacent intermediate plates 56 are equal to the workpiece. 11 can be kept at a suitable distance.

The correction table 52, the pressing member 54, and the intermediate plate 56 are provided with a heater (heater) 52b, a heater (heater) 54b, and a heater (heater) 56c, respectively. Each heater 52 b , 54 b , 56 c is connected to, for example, a power source (not shown) and generates heat that is used in straightening the workpiece 11 .

When the workpiece 11 is straightened by the straightening unit 50 configured as described above, for example, a pressing force is applied between the straightening table 52 and the intermediate plate 56, between two intermediate plates 56, or between the intermediate plate 56 and the intermediate plate 56. The workpiece 11 is carried in between it and the member 54 by the first transport mechanism 6 or the like. In this embodiment, as shown in FIGS. 3 and 4, one workpiece 11 is placed on each of the upper surface 52a of the correction table 52 and the upper surface 56b of the plurality of intermediate plates 56. FIG. That is, the number of workpieces 11 (four in the present embodiment) obtained by adding one to the number of intermediate plates 56 is carried into the correction unit 50 .

After the workpiece 11 is loaded, the actuator lowers the pressing member 54 . As a result, the lower surface 54a of the pressing member 54 comes into contact with the upper surface 11a of the workpiece 11, which is placed highest. When the pressing member 54 is further lowered, the uppermost intermediate plate 56 is gradually lowered, and the lower surface 56a of this intermediate plate 56 contacts the upper surface 11a of the workpiece 11 arranged below.

When the pressing member 54 is further lowered, the other intermediate plates 56 are similarly lowered gradually, and the lower surface 56a of each intermediate plate 56 contacts the upper surface 11a of the workpiece 11 below. Thus, the lower surface 56a of each intermediate plate 56 is in contact with the upper surface 11a of the workpiece 11 below (on the side of the correction table 52), and the upper surface 56b of each intermediate plate 56 is in contact with the upper surface (on the pressing member 54 side). ) of the workpiece 11 are in contact with each other.

When the pressing member 54 is further lowered, as shown in FIG. 4, each warped workpiece 11 is pushed downward by the pressing member 54 (and the intermediate plate 56), deformed and flattened. In this state, the heaters 52b, 54b, and 56c are operated to apply heat to the workpiece 11, thereby correcting the warped workpiece 11 and bringing the amount of warp a closer to zero. That is, in this embodiment, a plurality of workpieces 11 can be corrected at once. Note that the heaters 52b, 54b, and 56c may be activated in advance before the pressing member 54 is lowered.

A control unit 58 is connected to each element of the grinding device 2 . The control unit 58 is configured by a computer including, for example, a processing device, a storage device, and an input device, and controls the first transport mechanism 6 and the position adjustment mechanism described above so that the workpiece 11 is appropriately ground. 12. Controls the operation of each element including the warp amount measuring device 14, the second transport mechanism 16, the third transport mechanism 46, and the correction unit 50. FIG.

The processing device is typically a CPU (Central Processing Unit), and performs various processes necessary to control the elements described above. The storage device includes, for example, a main storage device such as a DRAM (Dynamic Random Access Memory) and an auxiliary storage device such as a hard disk drive and a flash memory.

The input device is, for example, a touch panel, and also serves as an output device (display device). Note that a keyboard, mouse, or the like may be employed as an input device. The functions of the control unit 58 are implemented by the processing device operating according to software stored in the storage device, for example. However, the functions of the control unit 58 may be realized only by hardware.

FIG. 5 is a functional block diagram showing part of the functional structure of the control unit 58. As shown in FIG. The control unit 58 includes a transport mechanism controller 58a that controls the first transport mechanism 6, the second transport mechanism 16, and the third transport mechanism 46, a measuring device controller 58b that controls the warp amount measuring device 14, and a correction unit. and a correction unit controller 58c that controls 50. The control unit 58 also includes a determination section 58d that performs various types of determination processing, and a storage section 58e that stores information necessary for the determination processing of the determination section 58d.

The flow of processing when the workpiece 11 is ground by the grinding device 2 will be described together with the functions of the control unit 58 . FIG. 6 is a flow chart showing a part of the flow of processing when the workpiece 11 is ground. When the grinding device 2 grinds the workpiece 11, first, the transport mechanism control unit 58a operates the first transport mechanism 6 to grind the unground workpiece 11 stored in the cassette 8b, for example. , to the position adjusting table 12a of the position adjusting mechanism 12 (step ST11).

Next, the control unit 58 adjusts the position of the workpiece 11 by the position adjustment mechanism 12, and then the measuring instrument control section 58b operates the warp amount measuring instrument 14 to measure the warp amount a of the workpiece 11. Measure (step ST12). The warp amount a measured by the warp amount measuring device 14 is stored in the storage section 58e of the control unit 58, for example.

When the warp amount a of the workpiece 11 is measured, the determination unit 58d determines whether or not the target workpiece 11 can be held by the chuck table 20 based on the warp amount a (step ST13). For example, when the workpiece 11 is greatly warped, negative pressure leaks from the gap between the workpiece 11 and the chuck table 20, and the workpiece 11 cannot be properly held.

Therefore, the determination unit 58d compares the warp amount a of the workpiece 11 measured by the warp amount measuring device 14 with a first threshold value b that defines the boundary of the allowable range of the warp amount a. Then, it is determined whether or not the warp amount a of the workpiece 11 is within the allowable range. The first threshold value b is composed of, for example, a threshold value b1 indicating a positive boundary (boundary regarding concave warpage) and a threshold value b2 indicating a negative boundary (boundary regarding convex warpage). , are stored in advance in the storage unit 58e.

In general, the gap at the outer edge between the workpiece 11 and the chuck table 20 is larger when the workpiece 11 has a concave warp than when the workpiece 11 has a convex warp. When there is a concave warp, the negative pressure is more likely to leak than when there is a middle convex warp. Therefore, the first threshold value b (threshold value b1, threshold value b2) is set so that the range of the amount of warp a that is allowed when there is a concave warp is the amount of warp a that is allowed when there is a convex warp. It is desirable to be set to be narrower than the range.

That is, it is desirable that the first threshold b is set and stored in the storage unit 58e such that the absolute value of the threshold b1 is smaller than the absolute value of the threshold b2. Typically, the threshold b1 (positive threshold) is set to 1 mm, and the threshold b2 (negative threshold) is set to −2 mm. However, this first threshold value b (threshold value b1, threshold value b2) can be appropriately changed according to the size of the workpiece 11, the ability of the suction source connected to the chuck table 20, and the like.

When the warp amount a falls within the range defined by the first threshold value b (typically when b1≧a≧b2 is satisfied), the determination unit 58d moves the workpiece 11 with the chuck table 20. It is determined that it can be held. Further, when the warp amount a does not fall within the range defined by the first threshold value b (typically, when a>b1 or b2>a is satisfied), the determination unit 58d It is determined that the workpiece 11 cannot be held.

In this manner, the determination unit 58d determines the workpiece 11 on the chuck table 20 based on the first threshold b stored in advance in the storage unit 58e and the warp amount a measured by the warp amount measuring device 14. can be held. The workpiece 11 that has been determined to be unable to be held by the chuck table 20 is later corrected using the correction unit 50 so that the warp amount a approaches zero.

When the determination unit 58d determines that the workpiece 11 can be held by the chuck table 20 (YES in step ST13), the transport mechanism control unit 58a operates the second transport mechanism 16 to hold the workpiece 11 on the position adjustment table 12a. The workpiece 11 that has been held is conveyed to the chuck table 20 (step ST14). The control unit 58 then controls the operation of each element to start grinding the workpiece 11 .

After transporting the workpiece 11 to the chuck table 20, if another unground workpiece 11 remains in the cassette 8b (YES in step ST15), the transport mechanism controller 58a controls the first transport mechanism 6 to convey another unground workpiece 11 housed in the cassette 8b to the position adjusting table 12a of the position adjusting mechanism 12 (step ST16). Then, the control unit 58 performs the same processing for this other unground workpiece 11 (step ST12, etc.).

There is no unground workpiece 11 left in the cassette 8b (NO in step ST15), and there is no workpiece 11 to be corrected (a workpiece 11 whose warp amount a is not within the allowable range). ) does not exist (NO in step ST17), the control unit 58 ends the series of processes after the ongoing grinding of the workpiece 11 is completed. The workpiece 11 for which grinding has been completed is accommodated in the cassette 8a by the first transfer mechanism 6 or the like.

If there is a workpiece 11 to be corrected (YES in step ST17), the transport mechanism control section 58a operates the first transport mechanism 6 to remove, for example, a workpiece temporarily stored in the cassette 8c. All the workpieces 11 are carried into the straightening unit 50 . Then, the correction unit control section 58c operates the correction unit 50 to start correcting the workpiece 11 (step ST18).

When the correction of the workpiece 11 is completed, the transport mechanism control unit 58a operates the first transport mechanism 6 to transport the corrected workpiece 11 to the position adjustment table 12a of the position adjustment mechanism 12. (Step ST19). Then, the control unit 58 performs similar processing on the workpiece 11 after correction (step ST12, etc.). When a plurality of workpieces 11 are corrected at once, it is preferable to store the other corrected workpieces 11 that are not conveyed to the position adjustment table 12a in the cassette 8b or the like.

FIG. 7 is a flow chart showing another part of the flow of processing when grinding the workpiece 11 . The determination unit 58d determines that the workpiece 11 cannot be held by the chuck table 20 (NO in step ST13), another unground workpiece 11 remains in the cassette 8b (YES in step ST21), and When the number of workpieces 11 to be corrected has reached the upper limit number that can be corrected at one time (YES in step ST22), the transport mechanism control section 58a operates the first transport mechanism 6 to 11 is transported from the position adjustment table 12a (step ST23).

For example, the transport mechanism control section 58 a carries the workpiece 11 held on the position adjustment table 12 a into the correction unit 50 . However, the transport mechanism control section 58a may load the workpiece 11 into the cassette 8c mounted on the cassette mounting table 10c and then load it into the correction unit 50. FIG. The upper limit of the number of corrections that can be performed at one time is set in advance according to the ability of the correction unit 50, for example, and stored in the storage section 58e. In this embodiment, for example, there are four.

Thereafter, the transport mechanism control unit 58a operates the first transport mechanism 6 to transport another unground workpiece 11 stored in the cassette 8b to the position adjustment table 12a of the position adjustment mechanism 12. (step ST24). The conveying mechanism control section 58a carries the workpieces 11 (three workpieces 11 in this embodiment) stored in the cassette 8c into the correction unit 50, and the correction unit control section 58c controls the correction unit 50. It is operated to start correcting the four target workpieces 11 (step ST25).

Further, the control unit 58 performs the same processing on another unground workpiece 11 that has been transported to the position adjustment table 12a (step ST12, etc.). After the straightening is completed, it is preferable to store the straightened workpiece 11 in the cassette 8b or the like.

Another unground workpiece 11 remains in the cassette 8b (YES in step ST21), and the number of workpieces 11 to be corrected has not reached the upper limit number that can be corrected at one time by the correction unit 50. If so (NO in step ST22), the transport mechanism control unit 58a operates the first transport mechanism 6 to transport the workpiece 11 held on the position adjustment table 12a and store it in the cassette 8c (step ST26).

In the present embodiment, the cassette 8c that can temporarily accommodate the workpiece 11 that has been determined not to be held by the chuck table 20 is used. good. In that case, for example, the workpiece 11 determined not to be held by the chuck table 20 can be temporarily accommodated in an empty shelf or the like of the cassette 8b.

Thereafter, the transport mechanism control unit 58a operates the first transport mechanism 6 to transport another unground workpiece 11 stored in the cassette 8b to the position adjustment table 12a of the position adjustment mechanism 12. (step ST27). Then, the control unit 58 performs the same processing on another unground workpiece 11 transported to the position adjusting table 12a (step ST12 and the like).

If the determination unit 58d determines that the workpiece 11 cannot be held by the chuck table 20 (NO in step ST13) and there is no other unground workpiece 11 left in the cassette 8b (NO in step ST21), the transfer The mechanism control unit 58a operates the first conveying mechanism 6 to move the workpiece 11 to be corrected on the position adjustment table 12a to the workpiece to be corrected stored in the cassette 8c as needed. 11 into the correction unit 50 .

Then, the correction unit control section 58c operates the correction unit 50 to start correcting the workpiece 11 (step ST28). When the correction of the workpiece 11 is completed, the transport mechanism control unit 58a operates the first transport mechanism 6 to transport the corrected workpiece 11 to the position adjustment table 12a of the position adjustment mechanism 12. (Step ST29). Then, the control unit 58 performs similar processing on the workpiece 11 after correction (step ST12, etc.). When a plurality of workpieces 11 are corrected at once, it is preferable to store the other corrected workpieces 11 that are not conveyed to the position adjustment table 12a in the cassette 8b or the like.

As described above, the grinding apparatus 2 according to the present embodiment includes the first transport mechanism 6 and the second transport mechanism 16 for transporting the workpiece 11 accommodated in the cassette 8b to the chuck table 20, the workpiece 11 A warp amount measuring device 14 for measuring the warp amount a, a straightening unit 50 for straightening the warped workpiece 11, and a control unit 58 are provided. The control unit 58 also includes a storage unit 58e that stores a first threshold value b that defines the range of the warp amount a, a warp amount a of the workpiece 11 measured by the warp amount measuring device 14, and a storage unit 58e. and a determination unit 58d that determines whether or not the workpiece 11 can be held by the chuck table by comparing with the first threshold b stored in 58e.

Then, the control unit 58 transfers the workpiece 11 to the chuck table 20 by the second transfer mechanism 16 only when the determination section 58d determines that the chuck table 20 can hold the workpiece 11 . Therefore, only by storing an appropriate first threshold value b in the storage unit 58e, problems due to warping when the workpiece 11 is held by the chuck table 20 do not occur. In other words, according to the grinding apparatus 2 of the present embodiment, the efficiency of grinding the workpiece 11 is not lowered due to a problem when the workpiece 11 is held by the chuck table 20 .

Further, the control unit 58 corrects the workpiece 11 by the correcting unit 50 when the determination section 58d determines that the chuck table 20 cannot hold the workpiece 11 . Therefore, it is not necessary for the operator to correct the workpiece 11 using another device or the like so that the workpiece 11 can be properly held by the chuck table 20 . In other words, the work load of the operator can be reduced, and the efficiency of grinding the workpiece 11 can be improved. As described above, according to the grinding apparatus 2 of the present embodiment, the plate-like workpiece 11 that may be greatly warped can be efficiently ground.

It should be noted that the present invention is not limited to the description of the above-described embodiment and can be implemented with various modifications. For example, the grinding apparatus 2 of this embodiment employs a correction unit 50 that has a plurality of intermediate plates 56 and can correct a plurality of workpieces 11 at once. The unit may have no intermediate plate. In this case, the workpieces 11 are corrected one by one.

In the correction unit 50 of this embodiment, the correction table 52 is provided with a heater 52b, the pressing member 54 is provided with a heater 54b, and the intermediate plate 56 is provided with a heater 56c. The heater 52b, the heater 54b, and the heater 56c may be omitted if the workpiece 11 can be corrected only by deforming it.

Further, in the present embodiment, as the first threshold value b that defines the boundary of the allowable range of the amount of warpage a, the threshold value b1 indicating the boundary on the positive side and the threshold value b2 indicating the boundary on the negative side are stored in the storage unit. 58e, at least one of the threshold value b1 and the threshold value b2 should be stored in the storage unit 58e as the first threshold value b.

In addition to the first threshold value b, the storage unit 58e may further store a second threshold value c that defines a plurality of categories of the amount of warp a that cannot be held by the chuck table 20 . Typically, as the second threshold value c, a threshold value c1 (c1>b1) indicating the boundary of the warp amount a when there is a concave warp, and the warp amount a when there is a middle convex warp and a threshold value c2 (b2>c2) indicating the boundary of .

For example, when the warp amount a is equal to or greater than the threshold value c1 or the warp amount a is equal to or less than the threshold value c2, the determination unit 58d determines that the target workpiece 11 is in a section requiring a long time for correction (a section with large warp). determine that it belongs On the other hand, if the warp amount a is larger than the threshold b1 but smaller than the threshold c1, or if the warp amount a is smaller than the threshold b2 but larger than the threshold c1, the determination unit 58d classifies the correction as not requiring a long time ( It is determined that the target workpiece 11 belongs to the section with small warpage.

Then, the control unit 58, for example, collectively corrects the plurality of workpieces 11 stored in the cassette (temporary storage cassette) 8c by the correction unit 50 for each section. In this modified example, since the workpiece 11 can be straightened for each section according to the time required for straightening, more efficient straightening is possible. In other words, the plate-like workpiece 11 that may be greatly warped can be ground more efficiently.

In addition, the structures, methods, and the like according to the above-described embodiments and modifications can be modified as appropriate without departing from the scope of the present invention.

2: Grinding device 4: Base 4a: Storage unit 6: First transport mechanism 8a: Cassette 8b: Cassette 8c: Cassette (temporary storage cassette)
10a: cassette mounting table 10b: cassette mounting table 10c: cassette mounting table (temporary storage cassette mounting table)
12: Position adjustment mechanism 12a: Position adjustment table 12b: Pin 14: Warpage measuring device 14a: Arm 14b: Laser distance measuring device 16: Second transport mechanism 18: Turntable 20: Chuck table 20a: Holding surface 22: Support Structure 24: Z-axis movement mechanism 26: Guide rail 28: Movement plate 30: Screw shaft 32: Motor 34: Fixture 36: Grinding unit 38: Spindle housing 40: Spindle 42: Mount 44a: First grinding wheel 44b: Second Grinding Wheel 46: Third Conveying Mechanism 48: Washing Unit 50: Correction Unit 52: Correction Table (Placement Section)
52a: upper surface (mounting surface)
52b: heater (heater)
54: pressing member (pressing portion)
54a: lower surface 54b: heater (heater)
56: Intermediate plate (intermediate part)
56a: lower surface (mounting section side contact surface)
56b: Upper surface (pressing part side contact surface)
56c: heater (heater)
58: Control unit 58a: Conveyance mechanism control section 58b: Measuring instrument control section 58c: Correction unit control section 58d: Determination section 58e: Storage section 11: Workpiece 11a: Upper surface 11b: Lower surface

Claims (8)

a chuck table having a holding surface for sucking and holding a plate-like workpiece;
a grinding unit having a spindle on which a grinding wheel including a plurality of grinding wheels is mounted, the grinding unit grinding the workpiece held on the chuck table with the grinding wheel;
a cassette mounting table on which a cassette capable of accommodating a plurality of workpieces is mounted;
a transport mechanism for transporting the workpiece accommodated in the cassette to the chuck table;
a warp amount measuring device for measuring the warp amount of the workpiece;
a straightening unit for straightening the warped workpiece;
a control unit that controls the conveying mechanism, the warp amount measuring device, and the correction unit;
The control unit is
a storage unit that stores a first threshold that defines the range of the amount of warpage;
comparing the warpage amount of the workpiece measured by the warpage amount measuring device with the first threshold value stored in the storage unit to determine whether the workpiece can be held by the chuck table; and a determination unit that determines whether
After measuring the amount of warpage of the workpiece with the warp amount measuring device, when the determining unit determines that the chuck table can hold the workpiece, the workpiece is moved by the conveying mechanism. A grinding apparatus that conveys the workpiece to the chuck table and corrects the workpiece with the correction unit when the determination unit determines that the workpiece cannot be held by the chuck table. The correction unit is
a mounting portion having a mounting surface on which the workpiece is mounted;
2. The pressing part that is arranged on the mounting surface side of the mounting part and applies force to the workpiece mounted on the mounting surface from the side opposite to the mounting surface. grinding equipment. 3. The grinding apparatus according to claim 2, wherein a heater is provided on one or both of said placing portion and said pressing portion. The correction unit is
Placed between the placing portion and the pressing portion, a placing portion side contact surface that contacts the work piece on the side of the placing portion, and a contact surface on the side of the pressing portion that contacts another work piece 4. The grinding apparatus according to claim 2, further comprising an intervening portion including a pressing portion side contact surface. 5. The grinding apparatus according to claim 4, wherein a heater is provided in said intervening portion. further comprising a temporary storage cassette mounting table on which a temporary storage cassette that can temporarily store a plurality of workpieces determined to be unholdable by the chuck table is mounted;
When the determination section determines that the workpiece cannot be held by the chuck table, the control unit stores the workpiece in the temporary storage cassette by the conveying mechanism, and then stores the workpiece in the temporary storage cassette. 6. The grinding apparatus according to claim 4, wherein said correction unit corrects a plurality of said workpieces that are accommodated at once. The storage unit further stores a second threshold that defines a plurality of categories of the amount of warpage that cannot be held by the chuck table,
The determination unit compares the warp amount of the workpiece measured by the warp amount measuring device with the second threshold value stored in the storage unit, and determines that the workpiece cannot be held by the chuck table. further determining which of the plurality of categories the workpiece to be processed belongs to,
7. The grinding apparatus according to claim 6, wherein the control unit corrects the plurality of workpieces stored in the temporary storage cassette by the correction unit for each section. The control unit is
8. The grinding apparatus according to any one of claims 1 to 7, wherein after the workpiece is straightened by the straightening unit, the amount of warpage of the straightened workpiece is measured again by the warp amount measuring device. .

Images