CN-114248196-B - Grinding device

Abstract

The present invention provides a polishing apparatus which shortens polishing time and makes the in-plane thickness of a wafer uniform. The polishing device (1) comprises a chuck table (50) for holding a wafer (90) by a holding surface (502), a slider (59) for moving the chuck table to a position where the held wafer can be polished, and a control unit (19) comprising a 1 st polishing unit (30) for disposing a 1 st polishing pad (306) having a lower surface covering at least the area of the upper surface of the wafer at the lower end of the 1 st spindle, and a 2 nd polishing unit (32) for disposing a 2 nd polishing pad (326) having a lower surface having a diameter smaller than the diameter of the wafer at the lower end of the 2 nd spindle, wherein the control unit controls the 1 st polishing pad to polish the wafer held by the holding surface and the 2 nd polishing pad to polish a predetermined portion of the radius area of the wafer polished by the 1 st polishing pad.

Inventors

• Shan Zhongcong

Assignees

• 株式会社迪思科

Dates

Publication Date

20260512

Application Date

20210910

Priority Date

20200923

Claims (2)

1. 1. A polishing apparatus, comprising: A chuck table for holding a wafer by a holding surface; A table rotating unit that rotates the chuck table; a polishing unit that is configured to dispose a polishing pad for polishing a wafer at a lower end of the spindle and polish the wafer using a lower surface of the polishing pad; a slider for rotating the chuck table about a rotation axis having an axial direction as a vertical direction to a polishing position where the polishing unit can polish the wafer held by the holding surface, or linearly moving the chuck table in a horizontal direction to the polishing position The control unit is used for controlling the control unit, Wherein, the The polishing unit has: A1 st polishing unit that disposes a1 st polishing pad having a lower surface covering at least the entire upper surface area of the wafer at the lower end of the 1 st spindle; A2 nd polishing unit for disposing a2 nd polishing pad having a lower surface with a diameter smaller than that of the wafer at the lower end of the 2 nd spindle; a horizontal moving unit that moves the 2 nd polishing unit in a horizontal direction; a3 rd polishing unit that disposes a3 rd polishing pad, which is formed of a diameter smaller than the radius of the wafer and that can surround the size of the 2 nd polishing pad, at the lower end of the 3 rd spindle; an X-axis moving unit for moving the 3 rd polishing unit in a horizontal direction, and A thickness measuring device for measuring the thickness of the wafer polished by the 1 st polishing pad and held on the holding surface, The control unit performs control as follows: Moving the chuck table to a position below the 1 st polishing pad, and polishing the wafer held by the holding surface by the 1 st polishing pad; Measuring a plurality of thickness values of the wafer in an arc-shaped or linear radius region from the center to the outer periphery of the wafer using the thickness measurer; polishing by tracing with the 3 rd polishing pad positioned in a circular shape in a plan view centered on the center of the wafer by the X-axis moving unit based on a plurality of thickness values of the wafer measured by the thickness measuring device and having a thickness difference larger than other portions, and The 2 nd polishing pad having a larger thickness and a thickness difference than other portions is positioned by the horizontal moving unit on a plane circular ring-shaped portion centered on the center of the wafer based on the plurality of thickness values of the wafer measured by the thickness measuring unit, and is subjected to finish polishing.
2. 2. The polishing apparatus according to claim 1, wherein, The grinding device has more than two of the 2 nd grinding units.

Description

Grinding device Technical Field The present invention relates to a polishing apparatus for polishing a workpiece such as a semiconductor wafer. Background For example, in a polishing apparatus for polishing a wafer using a polishing pad disclosed in patent document 1, a polishing pad covering an area of an upper surface of a wafer held by a chuck table is attached to a spindle, the spindle is rotated, the chuck table holding the wafer is rotated, and the polishing pad is pressed against the wafer to polish the wafer. In the wafer polished in this way, there is a case where uneven thickness such as waviness is generated in concentric circles around the center of the wafer. Accordingly, for example, as disclosed in patent document 2, polishing is performed while relatively reciprocating the chuck table and the polishing pad in a horizontal direction parallel to the holding surface, so that uneven thickness is not formed on the wafer, and the difference in thickness of the polished wafer is reduced. Patent document 1 Japanese patent laid-open publication No. 2003-305643 Patent document 2 Japanese patent laid-open No. 2007-318041 However, even if polishing is performed while relatively reciprocating the polishing pad and the wafer held by the chuck table in the horizontal plane direction, a slight thickness difference remains on the polished wafer. In addition, there is a problem in that a polishing pad in contact with a wafer is reciprocated in a horizontal direction, thereby resulting in a longer polishing time. Therefore, there is a problem to be solved in a polishing apparatus for polishing a wafer, in which the polishing time is shortened and the in-plane thickness of the polished wafer is made uniform. Disclosure of Invention The polishing apparatus for solving the above-mentioned problems comprises a chuck table for holding a wafer by a holding surface, a polishing unit for disposing a polishing pad for polishing the wafer at the lower end of a spindle and polishing the wafer by the lower surface of the polishing pad, a slider for moving the chuck table to a polishing position where the polishing unit can polish the wafer held by the holding surface, and a control unit for disposing a1 st polishing pad having a lower surface covering at least the area of the upper surface of the wafer at the lower end of the 1 st spindle, and a2 nd polishing unit for disposing a2 nd polishing pad having a lower surface smaller in diameter than the diameter of the wafer at the lower end of the 2 nd spindle, wherein the control unit controls such that the chuck table is moved to the lower side of the 1 st polishing pad and the wafer held by the holding surface is polished by the 1 st polishing pad, and a prescribed portion of the wafer polished by the 2 nd polishing pad is polished by the radius area of the 1 st polishing pad. The polishing apparatus of the present invention preferably includes a horizontal moving unit that moves the 2 nd polishing unit in a horizontal direction, and a thickness measuring device that measures a thickness of the wafer polished by the 1 st polishing pad and held on the holding surface, wherein the predetermined portion is a portion having a maximum thickness value among a plurality of thickness values of the wafer measured by the thickness measuring device, and the 2 nd polishing pad of the 2 nd polishing unit can be positioned at the predetermined portion by the horizontal moving unit. The polishing apparatus of the present invention preferably includes a carrying unit that carries a wafer into the holding surface or carries a wafer out of the holding surface, wherein the slider is capable of positioning the chuck table at a1 st polishing position, a2 nd polishing position, or a carry-in and carry-out position, wherein the 1 st polishing position is used for polishing a wafer held by the holding surface by the 1 st polishing pad, the 2 nd polishing position is used for polishing a wafer held by the holding surface at the carry-in and carry-out position, and the carrying unit is used for carrying a wafer into the holding surface or carrying a wafer out of the holding surface, wherein the control unit is used for polishing a wafer held by the holding surface by the 1 st polishing pad, and wherein the 1 st polishing pad is used for polishing a wafer polished by the 1 st polishing pad to the carry-in and carry-out position and the thickness is measured by the thickness measurer, and wherein a portion having a maximum thickness value among a plurality of thickness values of the wafer measured by the thickness measurer is used as the prescribed polishing pad 2 nd polishing pad. The polishing apparatus of the present invention preferably includes a3 rd polishing unit, wherein the 3 rd polishing unit is configured to dispose a3 rd polishing pad having a diameter smaller than a radius of a wafer and capable of surrounding a size of the 2 nd polishing pad at a lower end of the 3 rd spindle. The polis