CN101134303A - Polishing pad and method for manufacturing the same - Google Patents

Abstract

The invention provides a polishing pad and a manufacturing method thereof.A window is embedded in a polishing pad body, and a chemical bond is arranged between the window and the polishing pad body. The manufacturing method comprises the steps of placing an uncured colloid in a polishing pad mould, injecting a polishing pad material into the mould, curing the uncured colloid to form a window when the polishing pad material is formed, and forming a chemical bond between the polishing pad material and the window to obtain the polishing pad with the waterproof window.

Description

Polishing pad and method of manufacturing the same

technical field

The invention relates to a polishing pad, in particular to a polishing pad with a waterproof window.

Background technique

In recent years, chemical mechanical planarization (chemical mechanical planarization, referred to as CMP) has been widely used in semiconductor processes. It flattens the surface of the wafer through the relative motion between the wafer and the polishing pad while the slurry is present and pressure is applied. change. Please refer to Fig. 1, it is the schematic diagram of CMP equipment, and the equipment of CMP is called grinder usually, and wafer 10 is placed under wafer support seat 12 in grinder, and the platform that is arranged opposite to wafer support seat A polishing pad 16 is placed on 14, and a slurry 18 is sprayed on the polishing pad by a slurry sprayer 20, and is interposed between the wafer and the polishing pad.

There is usually a window on the polishing pad, and its purpose is to provide endpoint detection. During the grinding process, the laser light is used to penetrate the window to reach the wafer grinding surface to detect the state of the wafer surface, and thus to know whether the Material is ground to the correct thickness.

Please refer to Fig. 2, which is a schematic diagram of a traditional polishing pad manufacturing process. In the prior art, a solidified polymer material window 100 is placed in a polishing pad manufacturing mold 102, and then the polishing pad material 104 The material of the polishing pad is molded in the mold by injecting it into the mold 102 to form the polishing pad body 106 , that is, the polishing pad 110 with the window is completed.

The inventors of the present case found that in the traditional polishing pad 110, there is only physical interaction between the window 100 and the polishing pad body 106 to combine the two, so the waterproof effect between the window and the polishing pad body is not good. During the grinding process, the slurry will penetrate from the gap between the window and the polishing pad body to the bottom of the polishing pad, which will affect the bonding tape material between the polishing pad and the platform, and produce small air bubbles, resulting in the tightness between the polishing pad and the platform Poor and makes the surface of the polishing pad uneven. In this way, the CMP polishing effect of the wafer will be poor, and the desired planarization effect will not be achieved, which will further reduce the manufacturing yield or reliability of the components on the wafer.

Therefore, the industry urgently needs to improve the waterproof effect of the polishing pad window, so as to prevent the slurry from penetrating between the polishing pad and the platform, resulting in poor wafer polishing effect.

Contents of the invention

The invention provides a polishing pad, which includes a window embedded in the polishing pad body, wherein there is a chemical bond between the window and the polishing pad body.

The present invention further provides a method for manufacturing a polishing pad. An uncured colloid is placed in a mold of the polishing pad, then the material of the polishing pad is injected into the mold, and the material of the polishing pad is formed into a polishing pad body, and The uncured gum is cured to form a window, wherein a chemical bond is formed between the window and the body of the polishing pad, and then the mold is removed to obtain the polishing pad with the window.

In order to make the above-mentioned and other purposes, features, and advantages of the present invention more clearly understood, the preferred embodiments are specifically listed below, and in conjunction with the accompanying drawings, the detailed description is as follows:

Description of drawings

FIG. 1 is a schematic diagram of an existing polishing equipment for chemical mechanical planarization.

Fig. 2 is a schematic diagram of the existing polishing pad manufacturing process.

Figure 3A is a plan view of a polishing pad according to a preferred embodiment of the present invention.

FIG. 3B is an enlarged plan view of the dashed area in FIG. 3A .

FIG. 4 is a schematic diagram of a polishing pad manufacturing process in a preferred embodiment of the present invention.

Fig. 5 is a cross-sectional view of a polishing pad sample for vacuum testing according to a preferred embodiment of the present invention.

Explanation of main component symbols

10～wafer; 12～wafer support seat; 14～platform; 16～polishing pad; 18～slurry; 20～slurry sprayer; 100～cured window; 102, 32～mold of polishing pad; 104 , 38～polishing pad material; 110～traditional polishing pad; 28～uncured colloid; 30～window; 106, 40～polishing pad body; 50～polishing pad of the present invention; 301～window and partial polishing Area of the pad body; A, B～chemical bond; C～cutting line of cutting surface; D～cutting line of mating surface; E～initial polishing pad thickness; F～thickness of polishing pad sample for vacuum test; G～cutting thickness.

Implementation

The present invention provides an improved polishing pad, which has a waterproof window embedded in the polishing pad body, wherein there is a chemical bond between the window and the polishing pad body, so the window and the polishing pad body are very tightly combined, which can prevent the slurry from The gap between the window and the polishing pad body penetrates under the polishing pad.

Please refer to Fig. 3A, which is a plan view of the polishing pad of the present invention, wherein 30 is a window, and 40 is a polishing pad body, and the enlarged view of the area surrounded by dotted line 301 in Fig. 3A is shown in Fig. 3B, and arrows A and B represent A chemical bond is formed between window 30 and polishing pad body 40 .

The manufacturing flow of polishing pad of the present invention, referring to Fig. 4, at first uncured colloid 28 is placed in the mold 32 of polishing pad, then the material 38 of polishing pad is injected in the mould, makes the material foaming of polishing pad , form the polishing pad body 40, and make the uncured colloid 28 solidify to form the window 30, at this moment, form a chemical bond between the window 30 and the polishing pad body 40, the mold is removed, and the upper and lower sides of the window 30 and the polishing pad body 40 The polishing pad 50 with the window can be obtained by cutting the surface to the desired size, and the upper and lower surfaces of the window of the obtained polishing pad are coplanar with the upper and lower surfaces of the polishing pad body.

The polishing pad body of the present invention can be a polymer material, such as commonly used polyurethane (PU for short). The window can be a transparent polymer material, such as polycarbonate (PC for short), polyurethane (PU for short), or polymethyl acrylate (PMA for short). The uncured colloid is the same as the above-mentioned polymer material of the window, but it has not yet completed the curing reaction. In an embodiment of the present invention, the chemical bond between the window and the polishing pad body can be a hydrogen bond, PU is the material of the polishing pad, and the material of the window is also PU as an example, please refer to the following chemical formula 1, in the window and polishing Hydrogen bonding occurs between the pad bodies:

chemical formula 1

In addition, taking PU as the material of the polishing pad and PC as the window material, please refer to the following chemical formula 2, and hydrogen bonds will also be generated between the window and the polishing pad body:

chemical formula 2

In addition, if PU is used as the body material of the polishing pad, and the window material is PMA, hydrogen bonds will also be generated between the window and the body of the polishing pad. Please refer to the following chemical formula 3:

chemical formula 3

As mentioned above, there is a chemical bond between the window in the polishing pad of the present invention and the polishing pad body, which is closer than the window and the polishing pad body that utilize physical action in the traditional polishing pad, so the window in the polishing pad of the present invention has Better waterproof effect, during the grinding process, it can prevent the slurry from penetrating from the gap between the window and the polishing pad body to the bottom of the polishing pad, so as to achieve better CMP grinding results.

Then please refer to Fig. 5, it is the sectional view of polishing pad of the present invention, wherein the area 30 that dotted line surrounds is window, and 40 is polishing pad body, can clearly know that the upper and lower surfaces of window 30 of polishing pad and The upper and lower surfaces of the polishing pad body 40 are coplanar.

In order to test the window waterproof effect of the polishing pad, the upper and lower surfaces of the initial state of the polishing pad after molding were cut off to obtain a polishing pad with a relatively flat upper and lower surface to make a polishing pad sample for vacuum testing. Please refer to Figure 5 again, the surface cut along the dotted line C is called the cutting surface (polishing side), which is used as the contact surface with the slurry during the grinding process; the surface cut along the dotted line D is called the back side (back side) ), which is used as a bonding surface with the platform during the grinding process, wherein the initial thickness E of the polishing pad is about 5.5mm, the thickness F of the polishing pad after cutting is about 4.85mm, and the thickness G of the cut upper and lower surfaces About 0.35mm.

The test method of the window waterproof effect of the polishing pad is to use a vacuum test, stick the cut polishing pad test sample on the platform, and place the vacuum device on the cutting surface of the window, stop after 5 seconds of vacuuming, and wait After 30 seconds, measure the change value of the vacuum degree. The smaller the change value obtained, it means that the air leakage of the window is less, which means that the waterproof effect of the window is better.

With polishing pad of the present invention, compare with traditional polishing pad, take PU as the material of polishing pad, PC is the material of window as example, the vacuum test result of its window waterproof effect is listed in table 1 below:

Table 1

Polishing Pad Vacuum Variation Test (psi) of the present invention Traditional Polishing Pad Vacuum Change Test (psi) time 5 seconds 30 seconds change value 5 seconds 30 seconds change value cutting surface 80.2 79.9 0.3 80 79.4 0.6 Fitting surface 80.3 80 0.3 80.1 79.5 0.6

As can be known from the test results in Table 1, the vacuum variation value of the polishing pad of the present invention is 0.3, which is lower than the vacuum variation value of 0.6 of the polishing pad manufactured in the traditional way, so its window waterproofing effect of the polishing pad of the present invention is more traditional. Double the polishing pad.

Although the present invention has disclosed the preferred embodiment as above, it is not intended to limit the present invention, and any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention, so the protection of the present invention The scope should be defined by the appended claims.

Claims (15)

1. polishing pad comprises:

One polishing pad body; And

One window, it is embedded in this polishing pad body,

Wherein has chemical bond between this window and this polishing pad body.

2. polishing pad as claimed in claim 1, wherein this polishing pad body is a macromolecular material.

3. polishing pad as claimed in claim 2, wherein this polishing pad body is polyurethane (polyurethane is called for short PU).

4. polishing pad as claimed in claim 1, wherein this window is transparent macromolecular material.

5. polishing pad as claimed in claim 4, wherein this window is Merlon (polycarbonate is called for short PC), polyurethane (polyurethane is called for short PU) or PMA (polymethyl acrylate is called for short PMA).

6. polishing pad as claimed in claim 1, wherein totally one plane, the upper and lower surface of the upper and lower surface of this window and this polishing pad body.

7. polishing pad as claimed in claim 1, wherein this chemical bond comprises hydrogen bond.

8. the manufacture method of a polishing pad comprises:

One uncured colloid is positioned in the mould of a polishing pad;

The material of one polishing pad is flow in this mould;

The forming materials of this polishing pad is formed a polishing pad body, and make this uncured colloid solidify to form a window, wherein form chemical bond between this window and this polishing pad body; And

This mould is removed, to obtain the polishing pad of a tool window.

9. the manufacture method of polishing pad as claimed in claim 8, wherein the material of this polishing pad is a macromolecular material.

10. the manufacture method of polishing pad as claimed in claim 9, wherein the material of this polishing pad is a polyurethane.

11. the manufacture method of polishing pad as claimed in claim 8, wherein this window is transparent macromolecular material.

12. the manufacture method of polishing pad as claimed in claim 11, wherein this window is Merlon, polyurethane or PMA.

13. the manufacture method of polishing pad as claimed in claim 8, wherein this chemical bond comprises hydrogen bond.

14. the manufacture method of polishing pad as claimed in claim 8, wherein totally one plane, the upper and lower surface of the upper and lower surface of this window and this polishing pad body.

15. the manufacture method of polishing pad as claimed in claim 8, wherein the forming materials mode of this polishing pad is a foaming.

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