JPS60228068A - Polishing machine - Google Patents

Abstract

PURPOSE:To improve the accuracy of polishing, by sticking adhesive plates to the top and bottom of a base disk which is formed with a gear and interposed between a pair of surface plates, and by sticking wafer positioning plates to the adhesive plates, so as to polish wafers without using an adhesive agent. CONSTITUTION:An upper and a lower adhesive plates 14 is impregnated with water. Wafers 16 are pushed on the through holes 17 of an upper and a lower positioning plates 15 so that the wafers are kept in tight contact with both the sides of a base plate 13 because of the water impregnated in urethane sheets 14. After the base plate 13 is engaged with a sun gear 10 and an internal gear 7, an upper surface plate 3 is moved down to pinch the base plate between the upper surface plate and a lower surface plate 1. The upper surface plate 3 is rotated in a direction 6 and the lower plate 1 is rotated in a direction 2. At the same time, the sun gear 10 and the internal gear 7 are rotated to cause the base plate 13 to perform a planetary motion, and a polishing agent is supplied in between the upper and the lower surface plates 3, 1, so that the wafers 16 are polished. According to this constitution, the sticking work on the wafers is facilitated, and the flatness of the base plate is transferred to the wafers to improve the accuracy of the polishing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a polishing apparatus mainly used for polishing semiconductor wafers (hereinafter simply referred to as wafers).

[Technical background of the invention and its problems]

Conventionally, a wafer of silicon (St), for example, is subjected to a final finishing process by a boring process.

As shown in Figure 1, a wafer (A) is bonded to a support (C) made of metal, glass, ceramics, etc. that can rotate freely and can be raised and lowered (B). This is further carried out by pressing the support (C) against the rotating lapping machine (D). The most common bonding method at this time is wax bonding.

However, with bonding through wax, the non-uniformity of the adhesive layer thickness remains unchanged and the flatness of the wafer.

Requires practice. On the other hand, in recent years, as the density of integrated circuit elements has increased, the accuracy of wafers has become increasingly strict. However, since the wax is applied manually, there are limits to the uniformity and reproducibility of the adhesive layer thickness. Moreover, adhesion using wax.

Wax removal work is essential as post-processing.

This was a factor that hindered automation.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances.

It is an object of the present invention to provide a polishing apparatus capable of polishing a wafer without using an adhesive.

[Summary of the invention]

A disk-shaped substrate with gears formed on the outer periphery is inserted between a pair of surface plates in place of the carrier of the double-sided boring machine, and an adhesive plate that holds the wafer in close contact with the substrate is pasted. A positioning plate for positioning the wafer is attached onto the plate.

[Embodiments of the invention]

An embodiment of the present invention will be described below in detail with reference to the drawings.

FIGS. 2 and 3 show the construction of the main parts of the polishing apparatus for boring according to this embodiment. The lower surface plate (1) is formed into a cylindrical shape, and is driven by a first drive mechanism (not shown) as shown by the arrow (2).
It is designed to be rotationally driven in the direction. This lower surface plate (
An upper surface plate (3) is disposed above and coaxially opposed to the upper surface plate (3). This upper surface plate (3) is moved by an elevating mechanism (not shown).
It is designed to move up and down in the direction of arrow (4), which is the axial direction. This upper surface plate (3) is provided coaxially with the lower surface plate fl) at a position below the lower surface plate (1), and protrudes from a through hole (5) bored in the center of the lower surface plate (1). It is designed to mesh with the splined shaft when lowering. Then,
This spline shaft is rotationally driven by a second drive mechanism (not shown), and the upper surface plate (3) meshing with the spline shaft is rotated in the direction of the arrow (6). on the other hand,
A ring-shaped internal gear (7) is disposed on the outer periphery of the lower surface plate (1) and connected to the upper end of the hollow shaft (7a) so as to surround the lower surface plate (1). This internal gear (7).

The lower surface plate (1) is rotated in the direction of the arrow (8) by a third drive mechanism (not shown) provided below the surface plate (1) and connected to the hollow shaft (7a). Furthermore, the through hole (5) K of the lower surface plate (1) is provided with a hollow shaft (9) on the outside of the spline shaft.
) is inserted, and the sun gear ([ is coaxially connected to the upper end of this hollow shaft (9).
The lower end of 9) is connected to a fourth drive mechanism (not shown), and the fourth drive mechanism drives the sun gear in the direction of the arrow αυ force 00)
is located so that it can be rotated. Therefore, the internal gear (force, hollow shaft (7a), hollow shaft (9), sun gear 0@, and the third and fourth drive mechanisms are.

It constitutes a planetary movement mechanism α2. This sun gear (IQ
A disc-shaped substrate α3) with good parallelism and flatness and having a gear part (13a) formed on the outer periphery is interposed between and the internal gear (7) in mesh with each other. It is designed to rotate and revolve. Then, attach foamed urethane (urethane foam) (14) to both sides of the substrate A via double-sided tape.
, Q41 is attached. Furthermore, tenbrae) (+5), (1■) are attached to these urethane sheets αa and a4J via double-sided tape.
・The holes on the side of the number of eggs for positioning and holding the eggs are equally spaced and drilled. On the other hand, a polishing cloth (]Lfi81 is attached to the upper surface of the lower surface plate (1) and the lower surface of the upper surface plate (3).

In the polishing device with the above configuration, the urethane sheet α→,0
(A) is impregnated with water, template α5), (15)
Press the wafer (10...) onto the through-hole position η... area. Then...

Wafer (16)... Urethane sheet (14),
The water impregnated in (14) holds the substrate θ■ in close contact with both sides. Next, after meshing the board θ■ with the sun gear 00 and the internal gear (7), the upper surface plate (3
) is lowered to clamp the substrate (13) between the lower surface plate (1) and the upper surface plate (3). Thus, -the upper surface plate (3) is rotated in the direction of arrow (6), and the lower surface plate (1) is rotated in the direction of arrow (2).

At the same time, the sun gear α0 and the internal gear (7) are rotationally driven to cause the substrate (1) to move in a planetary motion.Furthermore, when an abrasive is supplied between the lower surface plate (1) and the upper surface plate (3),
The wafers (10...) are subjected to a boring process.

As described above, the polishing apparatus of this embodiment utilizes a polishing apparatus for single-sided boring, and instead of a carrier, a urethane sheet α (1) impregnated with water is used as a substrate 03) with good parallelism and flatness. , Through Q4, αe...
Since the wafers (16) are bonded together, the work of bonding the wafers (16), which conventionally required skill, becomes easier and simpler.

Moreover, instead of wax, 1. (c) Since the wafers (161...) are bonded through water, they are firmly attached to the substrate (1) when they are pressed between the lower surface plate (1) and the upper surface plate (3). , the flatness of the substrate (131) is transferred to the wafer (1e...) without changing the flatness, improving processing accuracy.

In the above embodiment, the wafers (16) are bonded to both sides of the substrate 02, but the wafers 06) may be bonded to only one of them. In this case, it is preferable to apply Teflon to the main surface of the substrate on the side to which the wafers 06) are not bonded and the main surface of the surface plate so that they can slide smoothly.

Furthermore, Urethane Sea H14! , fl□ may be replaced by an adhesive sheet that uses adhesive force to fix the υ wafer (16). Furthermore, the polishing apparatus of the present invention can be applied not only to polishing but also to lapping.

〔Effect of the invention〕

The polishing apparatus 1 of the present invention greatly facilitates and simplifies the work of bonding wafers, and is useful for promoting automation. Moreover,
Processing accuracy is improved because the flat surface of the substrate to which the wafer is bonded is completely transferred to the wafer. Therefore, this polishing device is a super LSI (La+4e 5cal
eInteII rated C1rcuit) It is suitable for polishing wafers for devices.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the conventional wafer bonding method, Fig. 2 is an exploded configuration diagram showing the main parts of a polishing apparatus according to an embodiment of the present invention, and Fig. 3 is a main part of the polishing apparatus shown in Fig. 2. FIG. (1) Lower surface plate, (3) Upper surface plate. Qno: Planetary motion mechanism, (13): Substrate. (14): Urethane sheet (adhesive board). (1: Template (positioning plate), (1e: Wafer (workpiece). (17): Through hole, Plate: Polishing cloth. Agent: Patent attorney Kensuke Chika (and 1 other person) Figure 1, Figure 3 figure

Claims (1)

[Claims] a pair of surface plates that are relatively movable toward and away from each other and rotatably driven, and have a polishing cloth attached to at least one opposing surface; and a disk-shaped substrate interposed between the pair of surface plates. , a planetary movement mechanism for planetary movement of the substrate; an adhesive plate fixed to at least the surface facing the polishing cloth of the substrate and holding the plate-shaped workpiece in close contact; and a bonding plate fixed to the adhesive plate. A polishing apparatus characterized by further comprising: a positioning plate having a through hole for positioning the workpiece.