Continuous pad feeding method for chemical-mechanical polishing

Details Continuous pad feeding method for chemical-mechanical polishing Continuous pad feeding method for chemical-mechanical polishing

1999-12-31

2001-04-03

Morgan, Eileen P. (Department: 3723)

Abrading

Abrading process

With critical temperature modification or control of work or...

C451S041000, C451S059000, C451S296000, C451S307000

Reexamination Certificate

active

06210256

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a chemical mechanical polishing (CMP) apparatus, and particularly to a pad feeding method suitable for use in a CMP apparatus.
2. Description of the Prior Art
Semiconductor fabrication has reached the deep sub-micron stage. In the deep sub-micron stage, the feature size and the depth of focus (DOF) of photolithography equipment are reduced, and the number of multi-level metal interconnect layers is increased. Consequently, how to maintain a high degree of surface planarity for the wafer has become a major topic of investigation.
Before the deep sub-micron era of semiconductor production, spin-on-glass (SOG) was employed to be the principle method of planarizing a silicon wafer. However, the method obtains moderate planarity in only local areas on the wafer surface. Without a global planarization of the wafer surface, quality of development after photographic exposure is degraded and the etching end-point is difficult to determine. These disadvantages reduce the yield of the wafer, and this reduction is a reason why SOG is substituted by chemical-mechanical polishing (CMP).
After semiconductor fabrication reached the deep sub-micron regime, CMP apparatus becomes a necessary apparatus of globally planarizing a silicon wafer. However, the polishing pad for a chemical mechanical polisher is a consumptive element. That is, the polishing pad needs to be changed after hundreds of polishing processes are performed.
FIG. 1
is a schematic view showing a conventional pad feeding mechanism in a CMP apparatus. As shown in
FIG. 1
, the CMP apparatus has a polishing platen
102
and a wafer carrier
110
, wherein the wafer carrier
110
can hold a wafer
104
downward to the polishing platen
102
. A polishing belt
100
, serving as a plurality of polishing pads, is applied for use in the pad feeding mechanism. When a polishing pad (a portion of the polishing belt
100
) on the polishing platen
102
needs to be changed, a terminal of the polishing belt
100
is pulled to spread out another unpolished portion of the polishing belt
100
to cover the polishing platen
102
.
Other portions of the polishing belt
100
are rolled for space consideration. However, when the roller-type polishing belt
100
are wholly consumed, the CMP apparatus should have a shutdown for replenishing a new polishing belt. Such replenishment is complicated and time-consuming. There is therefore a need to improve this conventional pad feeding mechanism.
SUMMARY OF THE INVENTION
In accordance with the present invention, a continuous pad feeding method for chemical-mechanical polishing (CMP) is disclosed. The method is suitable for use in a CMP apparatus, wherein the CMP apparatus includes a first polishing belt having two terminals. The first polishing belt serves as a plurality of polishing pads. A second polishing belt having two terminals is provided on the first polishing belt. One of the terminals of the second polishing belt is adhered to one of the terminals of the first polishing belt.
Preferably, the adhering step is performed as follows. A first adhesion is coated on a surface of the first polishing belt. A second adhesion is coated on a surface of the second polishing belt. The second polishing belt is put on the first polishing belt by aligning the surface of the first polishing belt with the surface of the second polishing belt.
The second polishing belt is put on the first polishing belt for replenishment, after the first polishing belt is almost wholly consumed. This replenishing mechanism saves the maintenance time and increases the throughput of the CMP apparatus.


REFERENCES:
patent: 5249393 (1993-10-01), Judge et al.
patent: 5899794 (1999-05-01), Shige et al.
patent: 5913716 (1999-06-01), Mucci et al.
patent: 6120359 (2000-09-01), Ohno et al.

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