Abrading – Machine – Combined
Reexamination Certificate
1999-11-03
2002-03-05
Eley, Timothy V. (Department: 3723)
Abrading
Machine
Combined
C451S446000, C451S910000
Reexamination Certificate
active
06352469
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
Chemical mechanical polishing (CMP) apparatus are known as apparatus for high precision polishing operations to be conducted on SOI substrates, semiconductor wafers made of Si, GeAs and/or InP, wafers carrying an insulation film or a metal film on the surface and produced in the process of forming semiconductor integrated circuits and substrates to be used for displays in order to meet the demand for extra-miniaturization and multi-level arrangement of semiconductor devices in recent years.
2. Related Background Art
Firstly, a known CMP apparatus will be described by referring to
FIG. 21
of the accompanying drawings.
FIG. 21
schematically illustrates a known CMP apparatus. Referring to
FIG. 21
, an object of polish (wafer)
100
is held by an object-of-polish-holding means
300
with the surface to be polished facing downward and polished by means of a polishing pad
200
typically made of polyurethane and having a caliber greater than the diameter of the object of polish
100
. The polishing pad
200
normally has undulations on the surface or is porous. The object of polish
100
is driven by a drive means (not shown) to rotate in the direction indicated by arrow S in FIG.
21
. On the other hand, the polishing pad
200
is held by a platen
400
and driven by another drive means (not shown) to rotate in the direction indicated by arrow T in FIG.
21
. As the object of polish
100
and the polishing pad
200
are made to abut each other under this condition, the contact surface of the object of polish
100
is polished.
During this operation, a polishing agent (slurry) is fed from a slurry supply means
500
to between the object of polish
100
and the polishing pad
200
that are held in touch with each other. Such a polishing agent typically contains fine particles (polishing particles) of SiO
2
having a size of sub-microns to microns and dispersed in an alkaline aqueous solution. As slurry is supplied to the object of polish, the latter is finely polished. In
FIG. 21
, slurry is fed to between the object of polish
100
and the polishing pad
200
from the outside of the object of polish
100
.
However, it is highly difficult to maintain the reproducibility of the polishing effect when polishing a plurality of objects continuously by means of a polishing apparatus having a configuration as described above. For example, the objects of polish can be polished to different extents and/or some of the objects of polishing can show unexpected scars on the surface. Such scars are mostly produced by particulate aggregates of fine dirt particles of external origins and/or those of polishing particles.
Additionally, the number of particulate aggregates increases with time. Conventionally, the slurry that is found to be containing particulate aggregates to a large extent is simply disposed as waste. Then, the operator is forced to frequently monitor the extent of the particulate aggregates to consequently raise the workload on the part of the operator.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a polishing method and a polishing apparatus that can supply slurry containing no large particles to the object of polish.
According to an aspect of the invention, the above object is achieved by providing a polishing apparatus of the type comprising:
an object-of-polish-holding means for holding an object of polish; and
a polishing head; and
adapted to polish said object of polish by causing the polishing surface of said polishing head to abut said object of polish, while supplying slurry to said object of polish held by said object-of-polish-holding means;
said polishing apparatus further comprising:
a container (or vessel) for containing said slurry;
an intake pipe for taking up said slurry from said container; and
a large-diameter-particle-screening means for screening off large diameter particles from the slurry leaving said intake pipe and being fed to said object of polish.
According to the invention, there is also provided a polishing method for supplying slurry from a container to an object of polish held by an object-of-polish-holding means and polishing said object of polish by means of a polishing head, said method comprising a step of:
supplying said slurry from said container to said object of polish by way of an intake pipe and screening off large diameter particles from the slurry leaving said intake pipe and being fed to said object of polish by a large-diameter-particle-screening means.
According to the invention, there is also provided a polishing apparatus of the type comprising:
an object-of-polish-holding means for holding an object of polish; and
a polishing head; and
adapted to polish said object of polish by causing the polishing surface of said polishing head to abut said object of polish, while supplying slurry to said object of polish held by said object-of-polish-holding means;
said polishing apparatus further comprising:
a container for containing said slurry;
an intake pipe for taking up said slurry from said container; and
a fractionizing means for fractionizing particulate aggregates contained in the slurry flowing through said intake pipe into fine particles.
According to the invention, there is also provided a polishing method for supplying slurry from a container to an object of polish held by an object-of-polish-holding means and polishing said object of polish by means of a polishing head, said method comprising a step of:
fractionizing particulate aggregates contained in the slurry taken up from a container and flowing in a given direction into fine particles by a fractionizing means.
According to the invention, there is also provided a polishing method for supplying slurry from a container to an object of polish held by an object-of-polish-holding means and polishing said object of polish by means of a polishing head, said method comprising steps of:
fractionizing particulate aggregates contained in the slurry flowing through a flow path running in a given direction into fine particles by a fractionizing means arranged at said flow path.
According to the invention, there is also provided a polishing apparatus of the type comprising:
an object-of-polish-holding means for holding an object of polish; and
a polishing head; and
adapted to polish said object of polish by causing the polishing surface of said polishing head to abut said object of polish, while supplying slurry to said object of polish held by said object-of-polish-holding means;
said polishing apparatus further comprising:
a first container for containing said slurry;
a fractionizing means for fractionizing particulate aggregates contained in the slurry contained in said first container into fine particles;
a transfer pipe for transferring said slurry from said first container to a second container;
a filter arranged in said transfer pipe for screening off particulate aggregates from the slurry passing through said transfer pipe; and
a feed pipe for feeding slurry from said second container to said object of polish.
According to the invention, there is also provided a polishing method for polishing an object of polish by causing the polishing surface of a polishing head to abut said object of polish, while supplying slurry to said object of polish held by an object-of-polish-holding means, said method comprising steps of:
fractionizing particulate aggregates contained in the slurry contained in a first container into fine particles;
screening off particulate aggregates from the slurry being transferred from said first container to a second container through a transfer pipe by means of a filter; and
feeding slurry from said second container to said object of polish by way of a feed pipe.
According to the invention, there is also provided a polishing apparatus of the type comprising:
an object-of-polish-holding means for holding an object of polish; and
a polishing head; and
adapted to polish said object of polish by causing the polishing surface of said polishing head to abut said object of
Miyazaki Kyoichi
Nishimura Matsuomi
Takahashi Kazuo
Canon Kabushiki Kaisha
Eley Timothy V.
Fitzpatrick ,Cella, Harper & Scinto
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