Information
-
Patent Grant
-
6558238
-
Patent Number
6,558,238
-
Date Filed
Tuesday, September 19, 200024 years ago
-
Date Issued
Tuesday, May 6, 200321 years ago
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Inventors
-
Original Assignees
-
Examiners
- Morgan; Eileen P.
- Shakeri; Hadi
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CPC
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US Classifications
Field of Search
US
- 451 87
- 451 285
- 451 287
- 451 88
- 451 446
- 451 453
- 451 36
- 451 282
- 451 60
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International Classifications
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Abstract
The present invention provides a polishing slurry reclamation system. In one embodiment, the polishing slurry reclamation system comprises a polishing apparatus having a polishing platen and a fluid delivery system positioned to deliver a slurry or a rinse to the polishing platen, a recovery drain adjacent the polishing platen, and a fluid diverter associated with the platen and configured to deflect a selected one of a slurry or rinse emanating from the polishing platen to the recovery drain.
Description
TECHNICAL FIELD OF THE INVENTION
The present invention is directed, in general, to semiconductor wafer processing and, more specifically, to an apparatus and method for reclamation and recycling of CMP (chemical/mechanical planarization) slurries.
BACKGROUND OF THE INVENTION
In the manufacture of integrated circuits (ICs), chemical/mechanical polishing (CMP) is used to provide smooth topographies of semiconductor wafer substrates, on which the ICs are formed, for subsequent lithography and material deposition. These CMP processes are well known within the IC fabrication industry.
One major problem associated with this process involves post-CMP handling of the polishing slurry. It is well known that a large percentage, perhaps as much as 75 percent to 85 percent, of the slurry is never fully utilized during semiconductor wafer planarization. Because of the physical constraints of the polishing apparatus, the slurry that actually performs the planarization, i.e., “used” slurry, is commingled with the slurry that is excess to the process needs, i.e., “unused” slurry. Therefore, while not directly separable from the “used” slurry, the “unused” slurry is carried off into the waste slurry drain. As such, the “waste slurry,” as it is considered, still comprises a large percentage of useable chemicals and abrasive.
A complicating factor for the process is that the polishing platen is frequently washed with de-ionized (DI) water delivered under pressure to the platen to rinse the platen of slurry between polishing steps. Of course, the DI water mixes with the waste slurry and dilutes the chemical etchants, thereby complicating waste slurry recovery and reuse. Presently, waste slurry, including the waste DI water, is collected from the polishing environment and given minimal processing so as to accommodate environmental concerns. That is, the slurry is processed to separate a majority of the solid particulate material from the liquid and the two by-products, the solids and liquids, are then disposed of by conventional methods. Therefore, considerable waste of the slurry component materials occurs. Also, a large portion of the liquid contains chemicals and increases the liquid volume that must be treated by the municipal water facilities. This larger-than-desired volume of liquid results in a higher-than-necessary bill for services from the municipal water treatment facility. Additionally, the greater usage of chemicals also contributes to increased cost.
Accordingly, what is needed in the art is an apparatus and method of use that efficiently separates waste slurry, including liquids, for recycling or reuse while minimizing liquid volume committed to waste water treatment.
SUMMARY OF THE INVENTION
To address the above-discussed deficiencies of the prior art, the present invention provides a polishing slurry reclamation system. In one embodiment, the polishing slurry reclamation system comprises a polishing apparatus having a polishing platen and a fluid delivery system positioned to deliver a slurry or a rinse to the polishing platen, a recovery drain adjacent the polishing platen, and a fluid diverter associated with the platen and configured to deflect a selected one of either a slurry or a rinse emanating from the polishing platen to the recovery drain.
Thus, in a general sense, the present invention provides a system and method for selectively diverting slurry or rinse water, whichever is currently in use, as it pours over the edge of the polishing platen to a selected recovery drain. Therefore, the user may minimize the volume of slurry and rinse water going into the sanitary sewer. This reduces cost by reducing the volume of waste fluids that is the basis of municipal charges for waste water treatment. The system additionally allows ready recovery of a highly concentrated waste slurry that may be either returned to the manufacturer for recycling or modified for reuse in the polishing process.
In another embodiment, the recovery drain is a slurry drain or a rinse drain. In alternative embodiments, the fluid diverter or polishing platen is selectively positionable to cause the selected one of either the slurry or rinse to be diverted to the recovery drain. In yet another embodiment, the fluid diverter comprises an annular diverter that is concentric about the polishing platen and configured to divert the selected slurry or rinse to the recovery drain when the annular boot is inflated. In a further aspect of this embodiment, the annular diverter may be an inflatable boot or a mechanical diverter.
In another embodiment, the fluid diverter is a fluid shield concentrically and selectively positionable about the polishing platen to divert the selected one of either a slurry or rinse to the recovery drain. In a further aspect of this embodiment, the fluid shield is in a fixed position adjacent the polishing platen.
The fluid diverter, in another embodiment, comprises inert gas nozzles positioned proximate a perimeter of the polishing platen and oriented to route the selected one of either the slurry or rinse to the recovery drain. In a further aspect of this embodiment, the gas nozzles are coupled to a gas nozzle conduit system integrally formed in the polishing platen. In a second aspect of this embodiment, the gas nozzles are adjacent the polishing platen and the system further includes a conduit system external the polishing platen and coupled to the gas nozzles. The conduit system is configured to deliver a gas to the gas nozzles. The gas discharge nozzles, in a third aspect of this embodiment, are connected to an inert gas source.
In another embodiment of the present invention, the fluid diverter is a vacuum system located adjacent the polishing platen and configured to remove slurry from the polishing platen. The vacuum system, in yet another embodiment, further comprises a vacuum system coupled to the recovery drain. The system, in another embodiment, further comprises a filter coupled to the recovery drain.
The foregoing has outlined, rather broadly, preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1
illustrates a partial sectional view of an advantageous embodiment of a polishing slurry reclamation system constructed according to the principles of the present invention;
FIG. 2
illustrates the polishing slurry reclamation system of
FIG. 1
with the platen vertically positioned so as to recover waste rinse water;
FIG. 3
illustrates a partial sectional view of an alternative embodiment of the polishing slurry reclamation system of
FIG. 1
;
FIG. 4
illustrates the polishing slurry reclamation system of
FIG. 3
with the fluid diverter positioned to recover waste rinse water;
FIG. 5
illustrates an elevational view of a second alternative embodiment of the polishing slurry reclamation system of
FIG. 1
;
FIG. 6
illustrates the polishing slurry reclamation system of
FIG. 5
with the fluid diverter positioned to recover waste rinse water;
FIG. 7
illustrates an elevational view of an alternative embodiment of the polishing slurry reclamation system of
FIG. 5
;
FIG. 8
illustrates the polishing slurry reclamation system of
FIG. 7
with the fluid diverter positioned to recover waste rinse water;
FIG. 9
illustrates a partial sectional view of an another alternative embodiment of the polishing slurry reclamation system of
FIG. 1
; and
FIG. 10
illustrates a partial sectional view of an alternative embodiment of the polishing slurry reclamation system of FIG.
9
.
DETAILED DESCRIPTION
Referring now to
FIG. 1
, illustrated is a partial sectional view of an advantageous embodiment of a polishing slurry reclamation system constructed according to the principles of the present invention. A polishing slurry reclamation system
100
comprises a polishing apparatus
110
, a polishing platen and polishing pad, collectively,
115
, a platen drive shaft
115
a,
a fluid delivery system
120
, a fluid diverter
130
, a slurry recovery drain
140
, a slurry recovery tank
145
, a rinse drain
150
, and a rinse recovery tank
155
. The fluid delivery system
120
is positionable with respect to the polishing platen
115
to deliver a fluid, collectively
125
, that may be either a slurry
125
a
or a rinse
125
b
(See
FIG. 2
) to the polishing platen
115
. One who is skilled in the art is familiar with such fluid delivery systems. The fluid diverter
130
, which, in one embodiment, may be likened to a toroidal, concentric fluid shield
130
located about the platen
115
, is positioned proximate the polishing platen
115
, while the platen
115
is positionable vertically with respect to the fluid diverter
130
by the platen drive shaft
115
a.
The fluid diverter
130
may completely surround the polishing platen
115
or be configured so as to funnel waste slurry
125
a
into a single location that is connected to the slurry drain
140
. The slurry drain
140
is connected to the slurry recovery tank
145
that is configured to receive waste slurry
125
a.
In
FIG. 1
, the platen
115
is positioned vertically so as to direct the used slurry
125
a
from the platen
115
, onto the diverter
130
, then to the slurry recovery drain
140
, and thence to the slurry recovery tank
145
.
Referring now to
FIG. 2
, illustrated is the polishing slurry reclamation system of
FIG. 1
with the platen
115
vertically positioned so as to recover waste rinse water. In this particular embodiment, the vertical position of the platen
115
may be changed to divert the slurry
125
a
or the rinse
125
b
to their respective tanks. In this position, rinse water
125
b
is directed from the fluid delivery system
120
to the polishing platen
115
. The rinse water
125
b
is forced off the platen
115
by centrifugal force from the platen rotation to collect in the bottom of the polishing apparatus
110
that comprises a polishing tank
112
. From the polishing tank
112
, the rinse water
125
b
is channeled to the rinse recovery tank
155
by the rinse drain
150
. Of course, while individual recovery tanks
145
,
155
have been shown, they may also be formed as a single recovery tank having separate compartments. Also, it should be noted that the positions of the rinse recovery tank
155
and the slurry recovery tank
145
may be reversed in other embodiments. Of course, one who is skilled in the art will recognize that the slurry recovery drain
140
and rinse drain
150
may alternatively be connected directly to an appropriate recycle/reuse/waste treatment facility or device (not shown).
Referring now to
FIG. 3
, illustrated is a partial sectional view of an alternative embodiment of the polishing slurry reclamation system of FIG.
1
. In this embodiment, a polishing slurry reclamation system
300
further comprises a diverter translation mechanism
310
coupled to the fluid diverter
130
. The diverter translation mechanism
310
enables the fluid diverter
130
to be translated vertically. Thus in the illustrated embodiment, the diverter
130
is positioned proximate the platen
115
thereby to direct slurry
125
a
emanating from the platen
115
into the slurry drain
140
and then to the slurry recovery tank
145
.
Referring now to
FIG. 4
, illustrated is the polishing slurry reclamation system of
FIG. 3
with the fluid diverter
130
positioned to recover waste rinse water
125
b.
To collect waste rinse water
125
b,
the fluid diverter
130
is translated vertically downward by the diverter translation mechanism
310
. In this position, waste rinse water
125
b
emanating from the platen
115
cascades onto the diverter
130
and then to the polishing tank
112
, into the rinse drain
150
, and then into the rinse recovery tank
155
.
Referring now to
FIGS. 5 and 6
, illustrated are elevational views of a second alternative embodiment
500
of the polishing slurry reclamation system of FIG.
1
. In this embodiment, a polishing slurry reclamation system
500
further comprises an inflatable annular boot
510
and a concentric receptacle
515
. Both the inflatable annular boot
510
and the concentric receptacle
515
are concentric about the polishing platen
115
. The inflatable annular boot
510
may be inflated as shown in
FIG. 5
thereby channeling the slurry
125
a
into the concentric receptacle
515
, the slurry drain
140
and the slurry recovery tank
145
. The inflatable annular boot
510
may likewise be deflated as shown in
FIG. 6
, thereby allowing the rinse water
125
b
to cascade over the inflatable annular boot
510
and down into the polishing tank
110
. Further recovery is as described above. Alternatively, one who is skilled in the art will readily understand that the annular boot
510
need not be inflatable but may rather be a mechanical diverter. In such an embodiment, the annular boot
510
may be positioned by a mechanical apparatus such as a drive motor (not shown) or pneudralic system between positions for slurry recovery (
FIG. 5
) and rinse recovery (FIG.
6
).
Referring now to
FIGS. 7 and 8
, illustrated are elevational views of an alternative embodiment of the polishing slurry reclamation system of FIG.
5
. In this embodiment, a polishing slurry reclamation system
700
further comprises a gas supply system
710
, a platen
715
that may be customized to incorporate a gas distribution system
720
, a conduit system
725
, gas nozzles
730
, and a gas
740
. The gas nozzles
730
are positioned proximate an edge
712
of the polishing platen
715
and are oriented to route the waste slurry
125
a
to the slurry drain
140
. Of course, the system may also be configured to use the gas supply and distribution systems
710
,
720
to route waste rinse
125
b
to an appropriately configured rinse drain
150
. The gas distribution system
720
conducts the inert gas
740
from the inert gas supply
710
through the conduit system external the polishing platen to the gas nozzles
730
that may be integrally formed or coupled to the polishing platen
715
. That is, the gas supply system
710
, through the conduit system
725
and the gas nozzles
730
, blows the inert gas
740
toward the concentric receptacle
515
. The inert gas
740
carries the waste slurry
125
a
with the gas
740
into the concentric receptacle
515
. As shown in
FIG. 8
, the gas supply system
710
is turned off, and the waste rinse water
125
b
cascades from the platen edge
712
into the polishing tank
112
to be recovered in the waste rinse tank
155
.
Referring now to
FIG. 9
, illustrated is a partial sectional view of an alternative embodiment of the polishing slurry reclamation system of FIG.
1
. In this embodiment, a polishing slurry reclamation system
900
comprises a vacuum system
910
coupled to the recovery drain
140
through the waste slurry tank
145
. This allows the waste slurry tank
145
to be evacuated and the vacuum thereby created assists in the removal of slurry
125
a
to the slurry recovery tank
145
. Slurry
125
a
may be drawn through the recovery drain
140
proximate the platen
115
, or through an optional slurry conduit
940
positioned over the slurry
125
a
on the platen
115
. Of course, similar connections may also be made to the rinse tank
155
to use vacuum assist to remove rinse water.
Referring now to
FIG. 10
, illustrated is a partial sectional view of an alternative embodiment of the polishing slurry reclamation system of FIG.
9
. In this embodiment, a polishing slurry reclamation system
1000
further comprises a filter
1010
and a pump
1020
coupled to the recovery drain
140
through the waste slurry tank
145
. The filter
1010
assists in separating solid particles of the slurry
125
a
before the slurry recovery tank
145
. This embodiment may also incorporate a slurry level sensor
1030
that energizes the pump
1020
when a level of the slurry
125
a
is sufficient to prevent the pump
1020
from running dry.
Thus, several embodiments of a polishing slurry reclamation system have been described that incorporate a diverter of various forms to permit selectively routing waste slurry or waste rinse water to recovery tanks from whence the products can be recycled. Although the present invention has been described in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form.
Claims
- 1. A polishing slurry reclamation system, comprising:a polishing apparatus having a polishing platen and a fluid delivery system positioned to selectively deliver one of a slurry and a rinse to the polishing platen; a slurry recovery drain and a rinse recovery drain adjacent the polishing platen; and a fluid diverter concentric with and adjacent to the platen, wherein the polishing platen is selectively positionable relative to the fluid diverter to cause the selected one of the slurry and the rinse to be diverted to a selected corresponding one of the slurry recovery drain and the rinse recovery drain.
- 2. The system as recited in claim 1 wherein the polishing platen can translate vertically with respect to the fluid diverter.
- 3. A polishing slurry reclamation system, comprising:a polishing apparatus having a polishing platen and a fluid delivery system positioned to selectively deliver one of a slurry and a rinse to the polishing platen; a slurry recovery drain and a rinse recovery drain adjacent the polishing platen; and an annular, inflatable boot adjacent to and concentric about the polishing platen and configured to divert the selected one of the slurry and the rinse emanating from the polishing platen to a selected corresponding one of the slurry recovery drain and the rinse recovery drain.
- 4. A polishing slurry reclamation system, comprising:a polishing apparatus having a polishing platen and a fluid delivery system positioned to deliver a slurry or a rinse to the polishing platen; a recovery drain adjacent the polishing platen; and a fluid diverter comprising gas nozzles positioned proximate a perimeter of the polishing platen and oriented to route a selected one of a slurry or rinse emanating from the polishing platen to the recovery drain.
- 5. The system as recited in claim 4 wherein the gas nozzles are coupled to a gas nozzle conduit system integrally formed in the polishing platen.
- 6. The system as recited in claim 4 wherein the gas nozzles are adjacent the polishing platen and the system further includes a conduit system external the polishing platen coupled to the gas nozzles and configured to deliver a gas to the gas nozzles.
- 7. The system as recited in claim 4 wherein the gas discharge nozzles are connected to an inert gas source.
US Referenced Citations (17)