JP2000225561A - Grinding wheel starting point positioning mechanism in wafer grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly determine a starting point position of a grinding wheel for a short time by providing a sensor for sensing contact with a grinding wheel and a holding tool for holding a contact contacting a chuck mechanism on an upper side and a lower side, respectively, at a tip of an arm fixed in the horizontal direction. SOLUTION: By supplying air from an air supply port of a grinding wheel starting point positioning mechanism 16 and rotating an oscillation table 162e by an angle determined by a right angle adjusting bolt, a shaft 163 is rotated. A sensor 166a and a contact 166b held by a holding tool 167 in a lower side direction at a tip of an arm 164 fixed in the horizontal direction by an arm holder 165 on an upper side of a shaft are moved on a chuck mechanism 9b on which wafer of an index table 9 is not mounted yet. A grinding wheel 11 supported on a spindle shaft 10a is lowered, the grinding wheel 11 is brought into contact with the sensor 166a and a position where the contact 166b on the lower side of the sensor 166a is brought into contact with a surface of the chuck mechanism 9b is stored as a grinding wheel starting point in a CPU.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for determining a height position (starting point) of a grinding wheel at the start of grinding in a wafer grinding apparatus, and to start the grinding wheel at the start of grinding using the grinding wheel start point positioning mechanism. It relates to a method for determining the position of a point.

[0002]

2. Description of the Related Art A wafer chuck mechanism vertically mounted on a rotatable shaft, a grindstone mounted on a spindle shaft having the same axis as the shaft provided above the chuck mechanism, It is known to grind a wafer by pressing a grindstone against the wafer surface using a grinding device having an elevating mechanism, and rotating both a shaft of a chuck mechanism and a spindle shaft (Japanese Patent Application Laid-Open Nos. 4-346228 and 5-56). −77
148).

[0003] In addition, there is also a grinding apparatus that uses a plurality of grinding wheels mounted on a plurality of spindle shafts in order to reduce a wafer grinding time in the grinding apparatus by using a plurality of grinding wheels supported on a plurality of spindle shafts. Are known. For example, Japanese Unexamined Patent Publication No. 9-223680 discloses a pair of a wafer loading cassette 303 on the right side and a wafer unloading cassette 303 on the left side as shown in FIG.
Further, an articulated robot robot 304 having a lifting mechanism, a rotation drive mechanism, an alignment mechanism, and a control mechanism for driving each arm is arranged in the center of the both, and is arranged in the front row, and the wafer is placed on the base at the rear of the wafer loading cassette. The temporary mounting table B is arranged in the next row at the rear of the wafer unloading cassette with the wafer etching / cleaning mechanism 302 as a pair. (C) The base is hollowed out on the base in the rear row of the temporary mounting table and the cleaning mechanism. A rough grinding chuck mechanism 307 and a wafer finish grinding chuck mechanism 308 are arranged, and two grindstones suitable for each grinding zone are supported on a spindle shaft on a wall rising from the base of the chuck mechanism in the rear row. Grinding mechanism 3
01a and 301b are provided corresponding to the wafer chuck mechanism located in each grinding zone, and the row of the wafer temporary mounting table B and the etching / cleaning apparatus 302 and the chuck mechanism 307,
Rotary transfer means 3 in which three arms 305a each having an elevating mechanism, a rotary drive mechanism, and a suction pad at the tip are radially arranged on a shaft erected substantially at the center of the base between the rows of 308.
The present invention proposes a grinding apparatus 301 having the same.

Conventionally, in these grinding apparatuses, a spindle shaft having the same shaft center as the shaft provided above the chuck mechanism is provided for a wafer chuck mechanism which is vertically supported on a shaft rotatable before the start of grinding. Manually determining the starting point position according to the cutting depth of the grinding of the whetstone supported on the shaft is performed manually.

[0005] In this manual operation, the wafer is not placed on the wafer chuck mechanism, and the length is 10 mm, the width is 30 mm, and the thickness is 1 mm.
A rectangular block gauge of 2 mm is placed, then the grindstone supported by the spindle shaft is lowered, and the height position at which the grindstone contacts the block gauge is determined as the starting point (start point) of the grindstone. Is input to the CPU of the grinding machine to start automatic grinding of the wafer.

[0006]

In the conventional method of determining the starting point of the grinding wheel by hand, the position at which the block gauge is placed on the wafer chuck mechanism is not fixed due to the personality of the operator.
Further, there is a disadvantage that it takes a long time to determine the height of the starting point of the grinding wheel. The present invention aims at mechanizing the determination of the starting point of a grinding wheel.

[0007]

SUMMARY OF THE INVENTION The present invention provides a wafer chuck mechanism vertically mounted on a rotatable shaft, and a shaft mounted on a spindle shaft having the same axis as the shaft provided above the chuck mechanism. Grinding wheel, pressing the grindstone on the wafer surface using a grinding device having a spindle shaft elevating mechanism, and rotating both the chuck mechanism shaft and the spindle shaft to grind the wafer, the grinding wheel before pressing A positioning mechanism for determining a start position, wherein the whetstone positioning mechanism includes a rotary table fixed to a base, a rotation axis vertically supported by the rotary table, and a horizontal arm holder above the rotation axis by an arm holder. An arm fixed in the direction, and a gripper for holding a contact for contacting the chuck mechanism on the lower side with a sensor for sensing contact with the grindstone on the upper side at the tip of the arm. And characterized in that, there is provided a grinding wheel starting point positioning mechanism in a wafer grinding apparatus.

[0008] Since the positioning of the grinding start point of the grindstone in the wafer grinding apparatus is mechanized, the positioning operation can be performed in a short time, and the contacts and the sensors are placed at fixed positions on the chuck mechanism. Grinding thickness fluctuation is small.

According to the present invention, the arm of the whetstone starting point positioning mechanism is provided with an adjusting screw for contacting two leaf springs capable of finely adjusting the vertical position of the contact held by the gripper. It is characterized by having been done. Since the distance corresponding to the wafer thickness between the contactor and the chuck mechanism can be changed by the adjusting screw, the same grindstone starting point positioning mechanism can be used even when switching to a wafer having a different thickness.

The present invention further provides a method for determining the starting point of the grinding wheel in the next step using the grinding wheel starting point positioning mechanism. (1) The rotating shaft of the grindstone starting point positioning mechanism is rotated by a predetermined angle in a state in which the wafer is not placed on the chuck mechanism, and is directed downward to the tip of an arm fixed horizontally by an arm holder above the axis. Is moved to a fixed position on the chuck mechanism. (2) The grindstone supported by the spindle shaft is lowered to contact the grindstone with the sensor held on the upper side of the gripper, and the position where the contact provided on the lower side of the sensor contacts the surface of the chuck mechanism is referred to as the grindstone. Is stored in the CPU as the starting point of the.

It has become possible to mechanically position the starting point of the grinding wheel.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a top view of a grinding device provided with a grinding wheel start point positioning mechanism showing one embodiment of the present invention, FIG. 2 is a sectional view of an index turntable portion of the grinding device, and FIG. 4 is a side view of the grinding wheel start point positioning mechanism, FIG. 5 is a top view of the grinding wheel start point positioning mechanism, FIG. 6 is a bottom view of the grinding wheel start point positioning mechanism, and FIG. 7 is a rotary table used in the grinding wheel start point positioning mechanism. It is a perspective view of.

In the grinding apparatus shown in FIGS. 1 and 2,
1 is a grinding device, 2 is a wafer loading cassette placed on a mounting table located at the same level as a surface of a base 3 described later, 2 'is a wafer unloading cassette,
3 is a base, 4 is a floor, 5 is a robot, 5a is a frame standing upright from the base, 6 is a temporary wafer mounting table, 7 is a wafer cleaning mechanism,
8, 8 are transport pads, 8a and 8'a are suction pads, 8
b and 78'b are handles, 8c and 8'c are shafts, 9 is an index turntable provided at a location where the center of the base is hollowed out, s1 is a wafer loading / wafer unloading zone, and s2 is a rough grinding zone. , S3 is a finish grinding zone, 9a, 9b, 9c are chuck mechanisms, 10a, 10b
Is a wall erected from the base, 11 is a coarse grinding wheel, 11a is a first spindle shaft, 12 is a finishing wheel, 12a is a second spindle shaft, 13 is a chuck cleaning mechanism, 14 is a ceramic chuck cleaner, and 15 is polishing. 15a is a chuck mechanism, 15c is a cleaning liquid supply mechanism, 15d is an air supply nozzle, and 16 is a grindstone start point positioning mechanism.

In the grindstone start point positioning mechanism 16 shown in FIGS. 3 to 6, the grindstone start point positioning mechanism 16 is
Are fixed in the vertical direction via a flange portion 161a of the hollow column 161. 161b is a cover.
162 is a rotary table provided at the lower part of the support column, the perspective view of which is shown in FIG. 7, 162a is a right angle adjustment bolt, 162b is a left angle adjustment bolt, 162c is an air supply port, 162d is an air exhaust port, and 162e is a swing. It is a moving table.

163 is a vertical (vertical) on the swing table.
An axis erected in the direction and accommodated in the hollow portion of the support 161, an arm 164 is fixed to this axis by a holder 165, a sensor 166 a is a sensor, 166 b is a contact, and 167 is an upper side of the sensor, A gripper for holding the contact on the lower side of the sensor, 168a and 168b are fine height adjustment screws, 169a and 169b are leaf springs, and the fine adjustment screw is rotated to the right to lower the contact. When the is turned to the left, the contact rises.

The grindstone 11, which is supported on the spindle shaft 10a or 10b using the grindstone start point positioning mechanism 16,
The following steps are taken to determine the starting point of twelve. (1) Air is supplied from the air supply port 162c of the grindstone starting point positioning mechanism 16 in a state where the wafer is not placed on the chuck mechanism, and the swing table 162e is rotated by an angle determined by a right-angle adjusting bolt to rotate the shaft 163. Rotate
A chuck mechanism in which the sensor 166a and the contact 166b held downward by the gripper 166 are attached to the tip of an arm 164 fixed in a horizontal direction by an arm holder above the axis and the wafer of the index table 9 is not yet mounted. 9a,
Move over 9b or 9c. (2) Then, the grindstone 11 or 12 supported by the spindle shaft 10a or 10b is lowered, and the grindstone comes into contact with the sensor 166a held on the gripper at the upper side, and the contact 166b below the sensor is moved by the chuck mechanism. The position in contact with the surface is stored in the CPU as the grinding wheel start point. After raising the spindle shaft, air is exhausted from the air exhaust port 162d, and the arm fixed to the shaft 163 is moved to the left by rotating the swing table 162e to the left. Reference numeral 16 moves the sensor to a position that does not become an obstacle when the automatic grinding of the wafer is started.

Once the position of the starting point of the grinding wheel has been determined,
The grindstone starting point positioning mechanism is not used until the thickness of the newly ground wafer is changed. When continuously grinding wafers of approximately the same thickness, after grinding the previous wafer, the grinding wheel supported by the spindle shaft is retracted to the standby position, and the grinding wheel must be lowered to the starting point at a stretch when grinding the next wafer. Can be. Fine adjustment of the distance between the contact and the chuck mechanism is performed by adjusting the fine adjustment screw 16 according to the thickness of the wafer.
9a and 169b.

The grinding apparatus shown in FIGS. 1 and 2 (where the chuck mechanism provided on the index turntable is a, b, c)
In order to grind or grind and polish the wafer using the above (m = 3), the following steps are performed. (1) The wafer w is sucked from the wafer loading cassette 2 to the suction arm 5c of the articulated robot 5 suspended so that the suction arms 5b and 5c are on the lower side, and the wafer w is placed on the temporary mounting table 3.

(2) The index turntable 9 is rotated 120 degrees, the wafer on the temporary table is attracted to the transfer pad 8, and the transfer pad is rotated to load the wafer into a wafer loading / wafer unloading zone of the index turntable. The wafer is transferred to the chuck mechanism a of s1, during which the wafer is sucked from the wafer loading cassette to the suction arm of the articulated robot 5,
This is placed on a temporary table.

(3) Rotate the index turntable 9 by 120 degrees to set the chuck mechanism a to the coarse grinding zone s2.
After moving the chuck mechanism b to the wafer loading / wafer unloading zone s1, the first spindle shaft 10a is lowered to press the grindstone 11 against the wafer, and the chuck mechanism a and the first spindle shaft are rotated. Then, the first spindle shaft is raised, and during this time, the wafer on the temporary mounting table 3 is moved by the transfer pad 8 to the chuck mechanism of the wafer loading / wafer unloading zone s1 of the index turntable 9. b, and the wafer in the wafer loading cassette 2 is placed on the temporary table 3 using the articulated robot 5.

(4) The chuck mechanism a is moved to the finishing grinding zone s3 by rotating the index turntable 9 by 120 degrees, and the chuck mechanism b is moved to the rough grinding zone s2.
After moving the chuck mechanism c to the wafer loading / wafer unloading zone s1, the second spindle 10b is lowered to press the grindstone 12 against the wafer, and the chuck mechanism a and the spindle are rotated to finish the wafer. Grinding is performed, and then the second spindle shaft is raised, during which the first spindle shaft 10
is lowered to press the grindstone 11 against the wafer, and the chuck mechanism b and the spindle shaft are rotated to roughly grind the wafer. Then, the first spindle shaft is raised, and the wafer on the temporary mounting table 3 is removed. The wafer is transferred to the chuck mechanism c in the wafer loading / wafer unloading zone s1 of the index turntable by the transfer pad 8 on the left side, and the wafer in the wafer loading cassette 2 is placed on the temporary table 3 using the articulated robot 5. Put on.

(5) By rotating the index turntable 9 by 120 degrees, the chuck mechanism a is moved to the wafer loading / wafer unloading zone s1, the chuck mechanism b is moved to the finish grinding zone s3, and the chuck mechanism c is moved to the rough grinding zone s2. Then, the wafer that has been finished and ground by the right transfer pad 8 is transferred to a cleaning mechanism, and after the wafer has been cleaned, the articulated robot 5 is moved to the right side, and the finished and ground and cleaned wafer is transferred to the arm of the robot. Adsorb it and place it on the chuck mechanism 15a of the polishing machine 15,
The polishing pad 15b is pressed against the wafer surface, and a chuck mechanism,
The polishing is performed by rotating the polishing pad, and the surface of the polished wafer is cleaned with a cleaning liquid sprayed from the cleaning mechanism 15c.
Then, after drying by blowing air from the air supply nozzle 15d, the wafer is sucked to the suction arm of the articulated robot 5 and stored in the unloading cassette 2 on the right side.
Then, the transfer pad 8 on the left side is rotated to transfer the wafer on the temporary placement table 3 to the chuck mechanism a in the wafer loading / wafer unloading zone of the index turntable, while moving the articulated robot to the left. Then, the wafer is suctioned from the wafer loading cassette to the suction arm of the articulated robot, and the wafer is placed on the temporary mounting table. Meanwhile, the second spindle shaft is lowered to press the grindstone against the wafer, and the chuck mechanism b and The spindle is rotated to finish grind the wafer, then the second spindle is raised, and the first
The second spindle is lowered to press the grindstone against the wafer, the chuck mechanism c and the spindle are rotated to roughly grind the wafer, and then the first spindle is raised.

(6) One index turntable
By rotating the chuck mechanism by 20 degrees, the chuck mechanism b is moved to the wafer loading / wafer unloading zone, the chuck mechanism c is moved to the finish grinding zone, and the chuck mechanism a is moved to the coarse grinding zone, and the wafer finished and ground by the transfer pad is moved to the cleaning mechanism. After the transfer and cleaning of the wafer, the articulated robot is moved to the right to adsorb the finished ground and cleaned wafer to the arm of the robot, and this is placed on the chuck mechanism of the polishing machine, and the polishing pad is moved to the wafer. The surface is pressed, the chuck mechanism and the polishing pad are rotated to perform polishing, the surface of the polished wafer is cleaned and dried, and then the wafer is suctioned to the suction arm of the articulated robot and stored in an unloading cassette. Then, the wafer on the temporary table is rotated by rotating the transfer pad to load / unload the wafer from the index turntable. The robot is transferred to the chuck mechanism b in the Han loading zone, while the articulated robot is moved to the left, the wafer is sucked from the wafer loading cassette to the suction arm of the articulated robot, and the wafer is placed on the temporary table. In the meantime, the second spindle shaft is lowered to press the grindstone against the wafer, and the chuck mechanism c
Then, the finish grinding of the wafer is performed by rotating the spindle shaft, then the second spindle shaft is raised, and the first spindle shaft is lowered to press the grindstone against the wafer, and the chuck mechanism a and the spindle The shaft is rotated to roughly grind the wafer, and then the first spindle shaft is raised.

(7) One index turntable
By rotating the chuck mechanism by 20 degrees, the chuck mechanism c is moved to the wafer loading / wafer unloading zone, the chuck mechanism a is moved to the finishing grinding zone, and the chuck mechanism b is moved to the rough grinding zone, and the wafer that has been finished and ground by the transfer pad is moved to the cleaning mechanism. After the transfer and cleaning of the wafer, the articulated robot is moved to the right to adsorb the finished ground and cleaned wafer to the arm of the robot, stored in an unloading cassette, and then transferred. By rotating the pad, the wafer on the temporary table is transferred to the chuck mechanism c in the wafer loading / wafer unloading zone of the index turntable, while the articulated robot is moved to the left to attract the articulated robot. Attach the wafer from the wafer loading cassette to the arm and place it on the temporary table. In the meantime, the second spindle is lowered to press the grindstone against the wafer, the chuck mechanism a and the spindle are rotated to finish grind the wafer, and then the second spindle is raised, Further, the first spindle is lowered to press the grindstone against the wafer, and the chuck mechanism b and the spindle are rotated to roughly grind the wafer, and then the first spindle is raised.

(8) The rotation of the index turntable, the finish grinding and cleaning of the coarsely ground wafer, the polishing of the wafer, the accommodation of the polished wafer in an unloading cassette, and the wafer loading / wafering of a new wafer Steps (5) to (7) of transferring the unloading zone to the chuck mechanism and rough grinding of the wafer are repeated. When a polishing process for eliminating crushing scratches on the wafer grinding surface by the polishing machine is not necessary, the wafer cleaned and dried by the cleaning mechanism 7 is transported into the unloading cassette 2 by the articulated robot 5 and stored. I do.

When automatic grinding of a group of wafers is completed and a new group of wafers having different thicknesses is to be ground, the distance between the contact and the chuck mechanism is newly adjusted by fine adjustment screws 169a and 169b according to the wafer thickness. To adjust the starting point of the grinding wheel.

[0027]

The starting point position of the grinding wheel in the grinding apparatus of the present invention can be determined mechanically, so that the starting point position can be accurately determined in a short time.

[Brief description of the drawings]

FIG. 1 is a top view of a grinding device.

FIG. 2 is a sectional view of an index turntable portion of the grinding device.

FIG. 3 is a sectional view of a grindstone starting point positioning mechanism.

FIG. 4 is a side view of a grinding wheel start point positioning mechanism.

FIG. 5 is a top view of a grinding wheel start point positioning mechanism.

FIG. 6 is a bottom view of the grinding wheel start point positioning mechanism.

FIG. 7 is a perspective view of a rotary table.

FIG. 8 is a perspective view of another grinding apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Grinding apparatus 2 Cassette 3 Temporary mounting table 5 Articulated transfer robot 7 Cleaning mechanism 8 Transfer pad 9 Index turntable w Wafer 11 Rough grinding wheel 12 Finish grinding wheel 15 Polishing machine 16 Wheel start point positioning mechanism 169a Sensor 169b Contact

Claims (3)

[Claims] 1. A wafer chuck mechanism vertically mounted on a rotatable shaft, a grinding wheel mounted on a spindle shaft having the same axis as the shaft provided above the chuck mechanism, and a grinding wheel mounted on the spindle shaft. Using a grinding device with a lifting mechanism, press the grindstone on the wafer surface, rotate both the chuck mechanism shaft and spindle shaft to grind the wafer, and use a positioning mechanism to determine the starting point position of the grindstone before pressing The grinding wheel positioning mechanism includes a rotary table fixed to a base, a rotating shaft vertically supported by the rotary table, an arm horizontally fixed by an arm holder above the rotating shaft, and At the tip of the arm, a gripper for holding a contact that contacts a chuck mechanism and a sensor for sensing contact with the grindstone is provided on the upper side. To grindstone starting point positioning mechanism in a wafer grinding apparatus. 2. The arm according to claim 1, wherein the arm is provided with an adjusting screw for contacting two leaf springs capable of finely adjusting the vertical position of the contact held by the gripper. A grinding wheel start point positioning mechanism in a wafer grinding device. 3. An arm fixed horizontally by an arm holder by rotating a rotation axis of a grindstone start point positioning mechanism by a predetermined angle while the wafer is not placed on the chuck mechanism. The contact held by the gripper at the tip downward is moved to a fixed position on the chuck mechanism. (2) Then, the grindstone supported by the spindle shaft is lowered to move the gripper upward. Wafer grinding, characterized in that the position at which the grinding wheel contacts the held sensor and the contact provided below the sensor contacts the chuck mechanism surface is stored in the CPU and the starting point position of the grinding wheel at the start of grinding. A method to determine the starting point of the grinding wheel in the device.