JPS59187432A - Turn table - Google Patents

Abstract

PURPOSE:To increase the rigidity of a bearing portion, reduce snarling vibration and improve working accuracy by producing vacuum pressure in air chambers of rotary base and a fixed base to apply a prepressure to a bearing for supporting the rotary base. CONSTITUTION:A fixed base 2 supports rotatably a rotary base 1 through a ball bearing 3. A chuck table 6 fixedly adsorbs a workpiece 7 mounted on the upper surface of the rotary base 1 and provided on the fixedly adsorbing surface 8 with a air groove 9 for adsorption. An air hole 12 in the base 1 communicates to the air groove 9 and is connected to an air groove 13 provided on the outer periphery of the base 1. An air hole 14 communicates to an air chamber 20 provided in a space sandwiched between the rotary base 1 and the fixed base 2. The rotary base 1 is attracted to the fixed base 2 by vacuum pressure in an air chamber 20 so that prepressure is applied to the ball bearing 3 to urge the rotary base 1 against the fixed base 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotary table that indexes and rotates a chuck table of a wafer dicing apparatus mainly used as semiconductor manufacturing equipment.

Conventional structure and its problems Currently, in the semiconductor wafer guising process, there is a main shaft that rotates at high speeds of 20,000 to 30,000 revolutions per minute using an air bearing and a high-frequency motor, and a thin-walled diamond attached to this main shaft. The wheel (l) is completely suctioned onto the chuck table.
・Grooving or cutting has been done in one place. Here, in order to process weno into a 5M square pellet, it is necessary to process it in a grid pattern, and a rotary table is used to rotate the machining chuck table pO in parallel at regular intervals. is built into the dining device. In a typical die song machine, a chuck table that suctions and fixes the wafer is placed on the top surface of the rotary table, and then a slide is installed to slide the rotary table in a direction perpendicular to the aforementioned main axis, that is, parallel to the diamond wheel. It is placed on a table and the sea urchin/...- die song device is performed.

A conventional general rotary table will be explained with reference to FIG. Note that FIG. 1 also shows a chuck table for suctioning and fixing the wafer. The rotating base 101 is connected to the fixed base 104 via a radial bearing 102 and a thrust bearing 103.
It is rotatably supported by a rotary drive motor 105 and a harmonic drive speed reduction device 106. The chuck table 1°o7 is placed on the upper surface of the rotating base 10i, and the chuck table 107
A wafer 109 as a workpiece is suctioned and fixed onto the suction surface 108 of the wafer 109 . The wafer 109 is fixed on the suction surface 108
This is done by making the upper air groove 110 approximately vacuum pressure, and for this purpose, the chuck table 1072 rotation base 101 has an air hole 111 communicating with the air groove 110,
112, and an air hole 11 in the fixing ring 113.
An air groove 11 is provided on the outer periphery of the rotating base 101 in order to communicate with the rotary base 101.
5 to prevent the air holes from being blocked by rotation. The fixed ring 113 has seals 116 and 117 that prevent air leakage from the gap with the rotating base 101, and a joint 1 that connects the vacuum generator 118 and the air path 119.
20 is attached, the fixing ring 113 itself is fixed to the base 122 via the fixing block 121, and the fixing ring 113 itself is fixed to the base 122 via the fixing block 121,
2 is attached to a sliding table 2 (not shown). Further, the chuck table 107 has an air groove 123 on the contact surface with the rotating base 101, and communicates this with the air hole 112, and is fixed on the rotating base 101 using vacuum pressure to attract and fix the wafer 109. -C is here. Further, the rubber magnet ring 124 is attached to the rotating base 101 and is attracted to the fixed block 121 by magnetic force.

However, in the above configuration, the thrust bearing is
Since only the columns are incorporated, what prevents the rotating base 101 from lifting up is the weight 11i- of the chuck table 107 and rotating base ioi and the magnetic force of the rubber magnet ring 124, and the outer diameter of the chuck table 1.07 is about 16
Chuck table 1 for 051A 6 inch type
0γ is about 1.7, P, the rotating base 101 is about 2WD, the magnetic force of the rubber magnet 124 is about 319, and the total is about 6.7K.
I, and the rigidity as a rotary table is extremely weak. For this reason, it is a common semiconductor material and is easy to process like silicon wafers.
Thin materials with s as l and H require only a small processing load and can withstand use, but materials that are difficult to process, such as ferrite and sendust, which are used as materials for magnetic heads, and are as thick as 2M to 6M. When cutting something or grooving something deeply, the width of the diamond/wheel becomes thicker in terms of wheel strength, which increases the amount of grinding.With the conventional configuration, the rotary table vibrates due to the processing load. In other words, the workpiece material vibrates relative to the rotation of the tire pound wheel, so-called chatter vibration, which causes cracks and chipping in the workpiece 2, making it impossible to perform high-precision machining. was.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention increases the preload force on the bearing that obstructs the rotating base to reduce the vibration of the table due to the machining load, that is, reduces the vibration of the workpiece and increases the This provides a rotary table that can perform precision machining.

Structure of the Invention The present invention provides a rotating base, a fixed base that rotatably supports the rotating base via a bearing, a motor that rotationally drives the rotating base, and a space separated between the rotating base and the fixed base. A part of the MiJR is made into an air chamber by a sealed sole, and the air chamber of the MiJR is connected to a vacuum generator connected by an air path, and the vacuum pressure generated by the vacuum generator generates a pre-air chamber. is approximately a vacuum pressure, and this pressure pulls the rotary base toward the fixed base and applies a preload force to the bearing, thereby reducing chatter vibration of the table due to the machining load, that is, cracking and chipping. It has the unique effect of reducing the amount of carbon dioxide and allowing high-precision machining.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows a sectional view of a rotary table in an embodiment of the present invention, and FIG. 3 shows a top view of FIG. 2. In the figure, 1 is a rotating part, 2 is a fixed base that rotatably supports the rotating base 1 via a ball bearing 3 as a bearing, and 4 is a harmonic drive reduction device 5.
6 (is a chuck table placed on the upper surface of the rotary base 1 and fixes the workpiece 7 by suction); 8 (is its suction/fixing surface, and the suction/l' An air groove 9 is carved for J. 10 is a positioning ring for the chuck table 6 and the rotating base 1;
1 is an air hole communicating with the air groove 9; 12 is an air hole also provided inside the rotating base 1, communicating with the air groove 9, and one end connected to an air groove 13 machined on the outer periphery of the rotating base 1. Furthermore, the air groove 13 is configured to communicate with the air hole 14 of the stationary base 2 and the air groove 9 carved in the upper surface of the chuck table 6 at any rotational position of the rotary base 1. 16 is a joint that connects the air hole 14 and the direct air generator 16, 17 is an air joint path, 18.19 is a sealing ring that prevents air leakage from the gap between the rotating base 1 and the fixed base 2, and 2o is a 2 This air chamber is located between the seals 18 and 19 of the book, and is provided in a space sandwiched between the rotary base 1 and the fixed base, and communicates with the air hole 14. 21
A and 21b are air chambers provided at the mating surfaces of the chuck table 6 and the rotating base 1. Further, the input shaft 5a of the harmonic drive reduction gear device 5 is the motor shaft 4b of the mortar 4.
The fixing ring 5b is connected to the fixing base 2, as shown in FIG.
e It is fastened with a tightening bolt, and the output ring 5
C is also connected to rotating ring 1 by a tightening bolt (not shown).
It has been concluded.

The operation of the rotary table configured as described above will be explained below.

First, when the workpiece 7 is placed on the chuck table 6 by the operator and the vacuum generator 16 is operated, the air path 17. Air hole 14. Air front 13, air hole 12.1
1 becomes the vacuum pressure in sequence, and by the negative air pressure of the air groove 9 communicating with this, the workpiece 7 is fixed by suction on the chuck table 6 +hiB, and the workpiece 7 is also fixed on the air chamber 21a. , 21b, the chuck table 6 is suctioned and fixed to the rotating base 1 by vacuum pressure. Furthermore, the rotating base 1 is attracted to the fixed base 2 by the vacuum pressure of the single-volume air chamber 20, and a preload force is applied to the ball bearing 3, and the rotating base 1 is pressed against the fixed base 2 via the outer ring, balls, and inner ring of the ball bearing 3. It will be done. In this state, cutting or grooving is first performed in one direction, and then a rotation pulse is given to the motor 4 by a rotation signal from a control device (not shown), and the motor shaft 4b is rotated. Input shaft 5a of harmonic drive reduction gear connected to this
When rotated, in the harmonic drive device, the rotation angle of the output ring 6c is transmitted at a reduced speed to the fixed ring 5b, and the rotating base 1 is rotationally driven at a high reduction ratio.

At this time, the workpiece 7 is suctioned and fixed via the chuck table 6, and rotates integrally with the rotating base. In this way, after indexing at a certain angle, cutting or grooving is performed again to divide the workpiece into pellets or to perform grooving at various angles. Also, in this rotary table, the chuck table 6 is fixed to the rotary base by suction and not fastened with bolts, so that it can be easily replaced with the most suitable chuck table depending on the type and shape of the workpiece. .

As described above, according to this embodiment, the rotating base and the
If part of the space that is separated by the fixed base is made into an air chamber by sealing/ru, the projected surface area of the air chamber will be approximately 40 cr for a 6-inch rotary table where the outer diameter of the chuck table is approximately 160 cr. : When the vacuum pressure is 500 wHy and the rotating base is attracted to the fixed base with a force of about 26/, the combined weight of the chuck table and rotating base is about 4 times that of a conventional rotating table, and the rigidity of the bearing part is reduced. can be significantly improved. In other words, the chatter vibration of the table due to the machining load can be reduced and highly accurate machining can be performed.

In this embodiment, the air path for suctioning and fixing the workpiece 7 and the chuck table 6, and the air path for making the air chamber 2Q between the rotating base 1 and the fixed base 2 into vacuum power are connected to the fixed base 2. The vacuum generator 16
shared/but each with separate air passages,
A plurality of total generators Et may be used.

In this embodiment, 40 rotations of the motor are decelerated and transmitted to the rotating base 1 through the Moninoku reduction device 5, but other deceleration means may be used depending on the required level of indexing resolution. The speed may be directly transmitted to the rotating base 1 using a coupling or the like without being decelerated.

In addition to effect 1, the present invention makes a part of the space sandwiched between the rotating base and the fixed base an air chamber by a sealing hole,
A vacuum generator generates vacuum pressure in the air chamber and applies preload to the bearing that supports the rotating base. Compared to conventional rotary tables, the rigidity of the bearing part can be increased, and the processing load can be reduced. The chatter vibration of the rotary table can be reduced and machining accuracy can be improved, and the effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional rotary table, FIG. 2 is a sectional view of a rotary table according to an embodiment of the present invention, and FIG. 3 is a sectional view of a conventional rotary table.
FIG. DESCRIPTION OF SYMBOLS 1... Rotating base, 2... Fixed base, 3... Bearing, 4... Motor, 14.17... Air path, 16... Vacuum generator, 18.19 ...Sealing/-le, 20...Air chamber. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 2

Claims (1)

[Claims] A fixed base that rotatably supports the rotary base via a bearing, a motor that rotationally drives the rotary base, and a part of the space sandwiched between the rotary base and the fixed base is sealed. A rotary table comprising an air chamber, and a vacuum generator communicating with the air chamber through an air path.