JPS6020853A - Double-sided polishing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (11) Technical Field of the Invention The present invention relates to polishing operations, and more particularly to a method for double-sided polishing.

(bl Technology Background In the manufacture of semiconductor devices, the surface rff of the wafer is
This is an important process whose quality determines the performance of the device.

Borising equipment is usually used for this work, but
In recent years, double-sided polishing equipment has appeared in response to demands for improved productivity.

(C) Conventional technology and problems Figure 1 (al is a diagram showing the situation during polishing by the conventional method,
Figure 1 fb) is a diagram showing the situation where the upper surface plate is raised after polishing is finished. 1 is the upper surface plate, 2 is the lower surface plate, 3 and 4 are the polishing cloth, and 5a and 5b are the wafers, respectively. .

FIG.
This shows the situation where both sides of parts a and 5b are being polished.

A plurality of wafers 5a are placed between an abrasive cloth 3 made of, for example, a polyurethane nonwoven fabric spread on the lower surface of the surface plate 1, and an abrasive cloth 4 made of the same material as the abrasive cloth 3 spread on the upper surface of the surface plate 2.・5b
etc. are held together under a predetermined pressure, the surface plate 1 and the surface plate 2, for example, rotate in reverse, and furthermore, the wafers 5a, 5b, etc. are rotated independently by another drive mechanism (not shown). Then, water and ([1] abrasive are supplied, and the wafers 5a and 5
The top and bottom surfaces of parts b etc. are polished at the same time.

After polishing is completed, take out the wafers 5a, 5b, etc., and place the next wafer as shown in FIG. Wafers 5a and 5b are polished after polishing.
Due to the presence of water, etc., the top and bottom surfaces of the polishing cloth 3 and
4, so when the upper surface plate 1 is moved upward,
A wafer made of the material, for example 5a, adheres to the polishing cloth 4 and remains below.
Some wafers, for example, 5b, stick to the polishing cloth 3 and rise to the top, making the wafer's location inconsistent. Therefore, the conventional polishing method has the disadvantage that the wafer handling operation is unstable.

This principle applies not only when the object to be polished is a wafer, but also when the object to be polished is cut to the size of the surface to be polished and the weight of the object to be polished is small.

(dl Purpose of the Invention In view of the above-mentioned drawbacks of the conventional art, the purpose of the present invention is to
To provide a polishing method in which all objects to be polished adhere to a specific surface plate when an upper surface plate is moved upward to form a space.

tel Structure of the Invention The above-mentioned object is to cause the abrasive body sandwiched between the abrasive cloths to come into contact with the abrasive cloths by sliding on the abrasive cloths spread on each of two opposing surface plate surfaces. In the method of polishing a surface to be polished, the double-sided polishing method of the present invention is characterized in that the polishing cloths spread on each of the two surface plate surfaces are polishing cloths having different adhesion to the surface to be polished. achieved.

When the upper surface plate is moved upward to form a space, the object to be polished, such as a wafer, adheres to the side with greater adhesion.
It is possible to attach all objects to be polished to a specific platen side.

(f) Embodiments of the Invention Examples of the present invention will be described below with reference to the drawings. The same reference numerals refer to the same objects throughout the design.

Figure 2 (al), Figure 2 (bl), and Figure 2 (C1) are diagrams showing the situation in which the upper surface plate is raised after finishing grinding I7 in an embodiment according to the configuration of the present invention, and 3a, 3b, 3c and 4a respectively show abrasive cloths.

In the case shown in FIG. 2, the abrasive cloth 3a spread on the lower surface of the upper surface plate 1 is an abrasive cloth made of, for example, a polyester nonwoven fabric impregnated with polyurethane, and the rIITI! The cloth 4d is, for example, an abrasive cloth made of polyurethane nonwoven fabric. Wafer 5 at the end of polishing
The adhesion to the upper and lower surfaces of a, 5b, etc. is determined by the polishing cloth 4a.
is larger than the polishing cloth 3a, so when the upper surface plate 1 is moved upward to form a space, the wafers 5a and 5 are
b, etc. all adhere to the polishing cloth 4a and remain below, making it possible to stably remove the polishing material with a pin.

Figure 2 (b1) In the case of illustration, the abrasive cloth spread on the upper surface of the lower surface plate 2 is the same 4a as above, and the abrasive cloth spread on the lower surface of the upper surface plate 1 has many small through holes in the abrasive cloth 4a. By providing the through holes, the adhesion of the polishing cloth 3b is made smaller than that of the polishing cloth 4a, and the wafers 5a, 5b, etc. are all attached to the polishing cloth 4, as in the previous embodiment.
It adheres to a and remains at the bottom.

Figure 2 (In the case of illustration C1, the abrasive cloth spread on the upper surface of the lower surface plate 2 is the same as 4a as above, and the abrasive cloth 3a spread on the lower surface of the upper surface plate 1 has many small through holes. The wafers 5a, 5b, etc. are all coated with the abrasive cloth 3c in order to obtain a synergistic effect between the two and to make the difference in adhesion larger than in the two embodiments. It adheres to 4a and remains below.

(gl Effects of the Invention As explained above, according to the configuration of the present invention, when polishing is completed and the upper surface plate is moved upward to form a space, all objects to be polished are moved to a specific surface plate. It is possible to provide a configuration of the polishing method that adheres to the side, which has the effect of making it possible to stabilize the handling of the object to be polished, such as a wafer.

[Brief explanation of the drawings] Figure 1 fal is a diagram showing the situation during polishing by the conventional method;
Figure 1 (bl is also a diagram showing the situation where the upper surface plate is raised after finishing the polishing, Figure 2 + al, Figure 2 (bl, Figure 2 (C)
1 is a diagram showing a situation in which the upper surface plate is raised after polishing in an embodiment according to the configuration of the present invention. In the drawing, 1 is the upper surface plate, 2 is the lower surface plate, 3.3a.3
b, 3c, 4, and 4a are polishing cloths, and 5a and 5b are wafers.

Claims (1)

[Claims] By sliding the polishing cloth spread on each of the two opposing surface plate surfaces, the object to be polished sandwiched between the gF polishing cloths is
In the method of polishing a surface to be polished that is in contact with the rff polishing cloth, the polishing cloth spread on each of the two surface plate surfaces includes:
A double-sided polishing method characterized in that the polishing cloths have different adhesion to the surface to be polished.