Surface grinding method and apparatus for thin plate work

• US 6,220,928 B1
• Filed: 04/29/1999
• Issued: 04/24/2001
• Est. Priority Date: 05/06/1998
• Status: Expired due to Fees

• Current Assignee: Shin-Etsu Handotai Co., Ltd. (Shin-Etsu Chemical Company Limited)
• Original Assignee: Shin-Etsu Handotai Co., Ltd. (Shin-Etsu Chemical Company Limited)
• Inventors: Kato, Tadahiro, Okuni, Sadayuki, Okabe, Keiichi, Oshima, Hisashi
• Primary Examiner(s): Eley, Timothy V.
• Assistant Examiner(s): BERRY JR, WILLIE WENDELL
• Application Number:
  US09/301,348
• Time in Patent Office: 726 Days
• Field of Search: 451/5, 451/287, 451/288, 451/11
• US Class Current: 451/5
• CPC Class Codes: B24B 49/00 Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation B24B33/06, B24B37/005 take precedence; if applicable to other machine tools, B23Q15/00 - B23Q17/00 take precedence
• CPC Class Codes: B24B 51/00 Arrangements for automatic control of a series of individual steps in grinding a workpiece if applicable to other machine tools, G05B takes precedence
• CPC Class Codes: B24B 7/228 for grinding thin, brittle parts, e.g. semiconductors, wafers grinding edges of thin, brittle parts B24B9/065

Abstract

The present invention provides a surface grinding method and apparatus for achieving a thin plate work such as a semiconductor wafer with high flatness, high accuracy and certainty and the apparatus comprises: a surface grinder in which a grinding wheel support member 3 by which a rotary shaft 5 of a grinding wheel 6 is supported is held by a pivotal shaft portion 4 and a grinding wheel shaft inclination control motor 9 which displaces the grinding wheel support member 3 by activating the pivotal shaft portion 4 is provided; a corrective angle storage device 15 which stores a corrective angle of an inclination angle of a rotary shaft 5 of the grinding wheel 6 to a rotary shaft 13 of a wafer 12; and a shaft inclination control apparatus 14 which sends out a signal to control the grinding wheel shaft inclination control motor 9 while reading a corrective angle of the corrective angle storage device 15, wherein a relative inclination angle of the grinding wheel to the thin plate work, in a more concrete manner an inclination angle of the rotary shaft 5 of the grinding wheel 6, is changed for each of grinding steps of high rate feed, low rate feed and spark-out.

Claims

1. A surface grinding method for a thin plate workpiece wherein a rotating, cup-shaped grinding wheel is pressed against the thin plate workpiece, said thin plate workpiece being supported on a table and rotating while the thin plate workpiece is ground by the grinding wheel, wherein a feed rate of the grinding wheel is changed step-wise during grinding, and an angle of inclination of the grinding wheel relative to the thin plate workpiece is also changed at substantially the same time the feed rate of the grinding wheel is changed.

2. A surface grinding method for a thin plate workpiece wherein a rotating, cup-shaped grinding wheel is pressed against the thin plate workpiece, said thin plate workpiece being supported on a table and rotating while the thin plate workpiece is ground by the grinding wheel, wherein a feed rate of the grinding wheel is changed step-wise during grinding, and an angle of inclination of the grinding wheel relative to the thin plate workpiece is also changed at substantially the same time the feed rate of the grinding wheel is changed, the feed rate of the grinding wheel being changed in multiple stages of high feed rate, low feed rate and no feed, and the relative angle of inclination of the grinding wheel to the thin plate workpiece being changed by a preset inclination corrective angle in each of the stages in which the feed rate is changed, whereby the surface of the thin plate workpiece is ground to an arbitrary target shape.

3. A surface grinding method for a thin plate workpiece according to claim 2, wherein when the thin plate workpiece is processed in the high feed rate, the low feed rate and the no feed stages, respective first, second and third inclination corrective angles are set which are inclined downwardly toward the periphery of the thin plate workpiece, and the respective inclination corrective angles are used sequentially for correction so that successive inclination corrective angles are closer to a horizontal direction.

4. A surface grinding apparatus which presses a rotating, cup-shaped grinding wheel against a thin plate workpiece which is to be processed, said grinding wheel being supported on a shaft and said workpiece being supported on a table and rotating while the thin plate workpiece is ground by the grinding wheel, a feed rate of the grinding wheel being changed step-wise during grinding, said apparatus comprising:

a grinding wheel feed rate adjuster for changing the feed rate of the grinding wheel stepwise;

a corrective angle store for storing a corrective angle for an inclination angle of the grinding wheel in each grinding step corresponding to a respective feed rate of the grinding wheel; and

a shaft inclination controller for controlling the inclination angle of the grinding wheel shaft relative to the thin plate workpiece in accordance with the corrective angle which is read from the corrective angle store, wherein the inclination angle of the grinding wheel shaft is changed by the shaft inclination controller for each of the grinding steps corresponding to the respective feed rates of the grinding wheel and the inclination angle and the feed rate are changed simultaneously.