JP3449505B2 - Setup method in polishing machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a setup method for a polishing apparatus. 2. Description of the Related Art A polishing apparatus for polishing a workpiece such as a wafer holds a workpiece W such as a wafer rotatably on a chuck table 1 as shown in FIG. 2 is lowered by the moving means 3 and the polishing section 2 of the polishing means 2
a is made to act on the workpiece W and the surface thereof is rotationally polished. In the above-mentioned conventional polishing apparatus, the polishing section 2a is usually provided with a polishing grindstone 4, and the polishing grindstone 4 is pressed against a workpiece W with a predetermined force. In order to perform polishing, a reference position of the polishing wheel 4 must be set in advance. The setting (set-up) of the reference position is conventionally inefficient because the dummy wafer is placed on the chuck table 1 and the operator works with a gap gauge (not shown) while visually observing the work. Was causing the decline. In addition, the present applicant has developed and completed a new polishing apparatus equipped with a polishing cloth in place of the polishing whetstone 4. However, the conventional method has been adopted for the set-up, and was not satisfactory. .
The present invention has been made to solve such a conventional problem, and provides a method of performing setup by directly contacting a polishing table and a chuck table arranged in a polishing section without using a dummy wafer. As an issue. [0004] As means for technically solving the above-mentioned problems, the present invention provides a chuck table for rotatably holding a workpiece such as a wafer, and a chuck table facing the chuck table. A polishing means including at least a polishing cloth including a polishing cloth disposed thereon, and a moving means for moving the polishing means to cause the polishing portion to act on the workpiece, wherein the rotation of the chuck table is kept free, and the polishing is performed. A first step of approaching the chuck table while rotating the unit, and when the polishing cloth contacts the chuck table and the rotation of the polishing unit is transmitted to the chuck table, the encoder detects the rotation of the chuck table and outputs a detection signal. Inputting to the CPU, wherein the CPU determines a reference position of the polishing unit in a second step. Is the gist. The polishing means is stepped downward while rotating the polishing section, and when the polishing cloth is rotated while contacting the rotation-free chuck table, the rotation is detected and processed by the CPU. The reference position of the polishing section can be set up. An embodiment of the present invention will be described below in detail with reference to the accompanying drawings (the same members as those of the prior art are denoted by the same reference numerals). In FIG. 1, reference numeral 1 denotes a chuck table of a polishing apparatus, which is rotated by a servo motor 5, and its rotation is detected by an encoder 6, and a detection signal is transmitted to a CPU 8 via a servo driver 7.
Is input to Reference numeral 2 denotes a polishing means, and a polishing cloth 9 is disposed on the polishing section 2a. The polishing means 2 includes a moving means 3
As a result, it is moved in the vertical direction (Z-axis) along the guide rail 10. The moving means 3 has a pulse motor 11, and the pulse motor 11
And a feed nut 1 screwed into the ball screw 12
The polishing means 2 is moved via the reference numeral 3. That is, the feed nut 13 is attached to a moving table 14 that moves along the guide rail 10, and the polishing means 2 is fixed to the moving table 14. Reference numeral 15 denotes a linear scale provided in association with the moving means 3, which reads a scale by a reading device 16 attached to the feed nut 13, and inputs a reading signal to the CPU 8. That is, the position of the polishing means 2 moved by the moving means 3 can be detected. A pulse motor driver 17 rotates the pulse motor 11 and inputs the number of rotation pulses to the CPU 8. FIG. 2 shows a flowchart of the setup method according to the present invention. First, as a first step, the pulse motor 11 is rotated by the pulse motor driver 17 connected to the CPU 8, and the polishing means 2 is moved downward. Send. At this time, the polishing unit 2a (polishing cloth 9) is rotated, and the chuck table 1 is in a rotation-free state with the servo lock of the servomotor 5 turned off. Next, as a second step, when the rotating polishing pad 9 is brought into contact with the chuck table 1, the chuck table 1 rotates, the encoder 6 detects the rotation, and the detection signal is transmitted to the servo driver 7. Is input to the CPU 8. The CPU 8 records the scale of the linear scale 15 when receiving the rotation signal of the chuck table 1, and uses the value as a reference position of the polishing unit 2a. Therefore, in this case, the setup can be performed by directly contacting the polishing pad 9 and the chuck table 1 without using the dummy wafer and the gap gauge. The number of pulses of the pulse motor 11 may be counted and the linear scale 15 may be omitted, but may be used together. Further, the control may be performed only by the linear scale. As described above, according to the present invention,
While rotating the polishing unit, the polishing means is stepped downward by the moving means, the chuck table is kept free of rotation, and the moment when the chuck table is brought into contact with the chuck table while rotating the polishing cloth is captured by the encoder. Since the reference position of the polishing section is determined, the chuck table is immediately rotated if the polishing cloth contacts even a small part of the chuck table in a stationary state, the rotation is detected by the encoder, and the detection signal is input to the CPU. Thus, the reference position of the polishing section can be detected. Thereby, there is an effect that the reference position of the polishing section can be detected with high accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. FIG. 2 is a flowchart of a setup. FIG. 3 is a perspective view of a main part of a conventional polishing apparatus. [Description of Signs] 1 ... Chuck table 2 ... Abrasive unit 2a ... Abrasive unit 3 ... Moving unit 4 ... Abrasive stone 5 ... Servo motor 6 ... Encoder 7 ... Servo driver 8 ... CPU 9 ... Abrasive cloth 10 ... Guide rail 11 ... Pulse Motor 1
2 Ball screw 13 Feed nut 14
Moving table 15 ... Linear scale 16 ... Reader 17 ... Pulse motor driver

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/304 B24B 1/00

Claims (1)

Claims: 1. A chuck table for rotatably holding a workpiece such as a wafer, a polishing means including a polishing cloth disposed opposite to the chuck table, and a polishing means. And a moving means for moving the polishing section to the workpiece by moving the chuck table. The first step of keeping the rotation of the chuck table free and rotating the polishing section to approach the chuck table. When the polishing cloth comes into contact with the chuck table and the rotation of the polishing section is transmitted to the chuck table, the encoder detects the rotation of the chuck table and inputs a detection signal to the CPU.
And a second step of determining a reference position of the polishing section by the CPU .