Abrading – Machine – Rotary tool
Reexamination Certificate
2000-06-02
2001-10-23
Morgan, Eileen P. (Department: 3723)
Abrading
Machine
Rotary tool
C451S443000, C451S285000
Reexamination Certificate
active
06306022
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a chemical-mechanical polishing (CMP) device. More particularly, the present invention relates to a chemical-mechanical polishing device with a porous dispensing tube.
2. Description of Related Art
In the manufacturing techniques of semiconductor devices, planarization surface is an important step in performing a high-density photolithography process. The planarized surface with little variation in height is easy to avoid the exposure diffusion and to achieve the precise pattern transfer. There are two major planarization techniques, Spin-On-Glass (SOG) and Chemical-Mechanical Polishing (CMP), however, in the sub-half-micron device era, the Spin-On-Glass method is incapable of providing required planarization and the Chemical-Mechanical Polishing method becomes the unique technique to provide global planarization on the manufacturing process of Very-Large Scale Integration; VLSI or even the Ultra-Large Scale Integration; ULSI circuitry.
FIGS. 1A and 1B
are a top view and a side view showing a conventional chemical-mechanical polishing device, respectively. As shown in
FIGS. 1A and 1B
, the device includes a polishing table
10
, a wafer holder
11
for wafer grabbing, a wafer
12
, a polishing pad
13
over the polishing table
10
, a tube
14
for carrying slurry
15
to the polishing pad
13
, a liquid pump
16
for pumping slurry
15
to the tube
14
, and a conditioner
17
for dressing the surface of the polishing pad
13
. When the chemical-mechanical polishing device is running, the polishing table
10
and the wafer holder
11
spin independently along a certain directions, as depicted as the reference numbers
18
a
and
18
b.
The wafer holder
11
grabbing the back side
19
of the wafer
12
, presses the front side
20
of the wafer
12
against onto the surface of the polishing pad
13
. The liquid pump
16
also works continuously to pump slurry
15
to the polishing pad
13
through the tube
14
. Therefore, the process of the chemical-mechanical polishing can rely on chemical reagents and abrasive particles suspended in the slurry
15
. The reagents react chemically with molecules on the front side
20
of the wafer
12
to form an easy-grind layer, while the abrasive particles of the slurry
15
help to remove the protrusion within the easy-grind layer. Via the continuous chemical reaction and repeated mechanical abrasion, a surface of high planarity is ultimately formed over the front side
20
of the wafer
12
. Basically, chemical-mechanical polishing is a technique of planarization, using the theory of mechanical polishing coupled with proper chemical reagents and abrasive particles to take off the fluctuated outline on the surface.
Polishing pad is a porous material, the cavities inside of the polishing pad could be stocked by the stuff used in the polishing process (such as abrasive particles of the slurry or something left during the process of wafer polishing) after using the polishing pad for a while, the performance of polishing may go down based on the changes of the characteristics of polishing materials. After a number of times of wafers polishing, the conditioner
17
would clean out the surface of polishing pad till the surface with cavities shows up. The polishing pad would not be renewed until the polishing pad could not be used anymore.
FIG. 2
is the bottom view of the conditioner, where on the rim of the main body
22
of conditioner
20
have a mounting pad
24
and each, is mounted with a plurality of diamond granules. The conditioners
20
use these diamond granules mounted on the polishing pad
24
to work when the chemical-mechanical polishing device is activated. However, these diamond granules could be nickel or the other kind of metal soldered on the mounting pad
24
of the conditioner
22
. While the chemical-mechanical polishing device is running, any kind of acid or basic slurry (especially for those acid slurry used in metal polishing) may erode those solders between the diamond granules and mounting pads
24
to get separated off from the mounting pads
24
and to shorten the life of conditioner
22
; also, those diamond granules left on the polishing pad may scratch the wafers in the process of polishing or later on to cause the destruction of devices.
SUMMARY OF INVENTION
Accordingly, the present invention provides a device for chemical-mechanical polishing which can be applied to the CMP machine. The CMP machine includes a chemical polishing table, which can be spinned in a fixed direction and has a polishing pad. A chemical-mechanical polishing device according to the present invention is at least comprised of a main body of conditioner with a plurality of mounting pads, wherein each mounting pad is mounted with the diamond granules and located on the lower surface of the conditioner, distributed on the rim of main body of each mounting pad. It can contact with polishing pads when cleaning the polishing pads and a number of cavities penetrate through the upper and lower surfaces of each main body of the conditioner and distributed between each mounting pads as well. When using the conditioners to clean out the polishing pads, the de-ionized water will flow through the cavities to wash off the acid or basic slurry to lower the rate of destruction made by the solders around the diamond granules to extend the durability of the conditioner.
In addition, the first type circular trench on the upper surface of conditioner is located inside the cavities, and more second type trenches are connected with the first type trench and cavities in vertical position. In order to move off the slurry, the second type of trenches transfuse the de-ionized water into the first type trench, and the water can evenly flow to the diamond granules on the polishing pads along the cavities to the next trenches.
The present invention will be better understood from the following detailed description of an exemplary embodiment thereof taken in conjunction with the appended drawings.
REFERENCES:
patent: 5456627 (1995-10-01), Jackson et al.
patent: 5486131 (1996-01-01), Cesna et al.
patent: 5626509 (1997-05-01), Hayashi
patent: 5683289 (1997-11-01), Hempel, Jr.
patent: 5913715 (1999-06-01), Kirchner et al.
Lin Lung-Hu
Tung Joseph
Wang Jiun-Fang
Yang Ming-Cheng
Huang Jiawei
J. C. Patents
Morgan Eileen P.
ProMOS Technologies Inc.
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