EP0881484A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for in-situ monitoring of thickness during chemical-mechanical polishing
Assignee: Lam Research Corp
•
Filing: 1998-05-28
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Granted: —
•
Expires: 2018-05-28
Abstract
Abstract An apparatus and method for in-situ monitoring of thickness during chemical-mechanical polishing (CMP) of a substrate using a polishing tool and a film thickness monitor. The tool has an opening placed in it. The opening contains a monitoring window secured in it to create a monitoring channel. A film thickness monitor (comprising an ellipsometer, a beam profile reflectometer, or a stress pulse analyzer) views the substrate through the monitoring channel to provide an indication of the thickness of a film carried by the substrate. This information can be used to determine the end point of the CMP process, determine removal rate at any given circumference of a substrate, determine average removal rate across a substrate surface, determine removal rate variation across a substrate surface, and optimize removal rate and uniformity.
Inventors
- 👤 Jiri Pecen
- 👤 Saket Chadda
- 👤 Rahul Jairaith
- 👤 Wilbur C. Krusell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 13:02
CPC Classifications
B; B24; B24B; B24B37/00; B24B37/11; B24B37/20; B24B37/205; B24B49/00; B24B49/02; B24B49/04; G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0616; G01B11/0683
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
144 words
In a chemical mechanical polishing device of the type comprising: a polishing
element, means for moving the polishing element along a polishing path, and a
substrate carrier positioned adjacent the polishing element to press a substrate against
the polishing element during a polishing operation; the improvement comprising: said polishing element having at least one opening formed therein, said
opening positioned to move into intermittent alignment with the substrate during the
polishing operation; said polishing element further comprising a monitoring window secured
to the polishing element to close the opening and to create a monitoring channel in the
polishing element; and said device further comprising a film thickness monitor, said film
thickness monitor comprising an ellipsometer responsive to optical radiation reflected
from the substrate through the monitoring channel during the polishing operation to
provide an indication of thickness of a film carried by the substrate.
Claim 2
Dependent Claim
146 words
In a chemical mechanical polishing device of the type comprising: a polishing
element, means for moving the polishing element along a polishing path, and a
substrate carrier positioned adjacent the polishing element to press a substrate against
the polishing element during a polishing operation; the improvement comprising: said polishing element having at least one opening formed therein, said
opening positioned to move into intermittent alignment with the substrate during the
polishing operation; said polishing element further comprising a monitoring window secured
to the polishing element to close the opening and to create a monitoring channel in the
polishing element; and said device further comprising a film thickness monitor, said film
thickness monitor comprising a beam profile reflectometer responsive to optical
radiation reflected from the substrate through the monitoring channel during the
polishing operation to provide an indication of thickness of a film carried by the
substrate.
Claim 3
Dependent Claim
152 words
In a chemical mechanical polishing device of the type comprising: a polishing
element, means for moving the polishing element along a polishing path, and a
substrate carrier positioned adjacent the polishing element to press a substrate against
the polishing element during a polishing operation; the improvement comprising: said polishing element having at least one opening formed therein, said
opening positioned to move into intermittent alignment with the substrate during the
polishing operation; said polishing element further comprising a monitoring window secured
to the polishing element to close the opening and to create a monitoring channel in the
polishing element; and said device further comprising a film thickness monitor, said film
thichness monitor comprising an optical stress generator beam and monitoring probe
beam responsive to reflected probe beam radiation from the substrate through the
monitoring channel during the polishing operation to provide an indication of thickness
of a film carried by the substrate.
Claim 4
Dependent Claim
17 words
The invention of Claim 1, 2, or 3, wherein the substrate carrier moves along a
closed path.
Claim 5
Dependent Claim
33 words
The invention of Claim 1, 2, or 3, wherein the film thickness monitor comprises
a light source operative to illuminate the substrate via the monitoring channel with
optical radiation during the polishing operation.
Claim 6
Dependent Claim
30 words
The invention of Claim 1, 2, or 3, wherein the moving means comprises a
plurality of rollers operative to drive the polishing element in a linear path past the
substrate.
Claim 7
Dependent Claim
32 words
The invention of Claim 6, wherein the film thickness monitor further comprises
a sensor for detecting when the monitoring window in the polishing element is in
alignment with the film thickness monitor.
Claim 8
Dependent Claim
37 words
The invention of Claim 1, 2, or 3, wherein the moving means comprises a
platen rotating about an axis that passes through its center operative to drive the
polishing element in a curved path past the substrate.
Claim 9
Dependent Claim
39 words
The invention of Claim 1, 2, or 3, wherein the moving means comprises a
platen rotating about an axis that does not pass through its center operative to drive
the polishing element in a curved path past the substrate.
Claim 10
Dependent Claim
33 words
The invention of Claim 1, 2, or 3. wherein the moving means comprises a
platen moving along a closed path operative to drive the polishing element in a curved
path past the substrate.
Claim 11
Independent Claim
89 words
A method for determining a thickness of a layer on a substrate during chemical-mechanical
polishing the method comprising the steps of: (a) performing chemical-mechanical polishing on a substrate by holding the
substrate in a substrate carrier against a polishing element, the polishing element having
a monitoring channel and being wetted with a polishing agent; and (b) using a film thickness monitor to determine a thickness of a layer on the
substrate during chemical-mechanical polishing when the monitoring channel in the
polishing element is aligned with the film thickness monitor.
Claim 12
Dependent Claim
13 words
The invention of Claim 11, wherein the film thickness monitor comprises an
ellipsometer.
Claim 13
Dependent Claim
15 words
The invention of Claim 11, wherein the film thickness monitor comprises a
beam profile reflectometer.
Claim 14
Dependent Claim
15 words
The invention of Claim 11, wherein the film thickness monitor comprises a
stress pulse analyzer.
Claim 15
Independent Claim
70 words
A method for determining an end point of a chemical-mechanical polishing
process, the method comprising the steps of: (a) measuring a film thickness of a substrate during a chemical-mechanical
polishing process when a monitoring channel in a polishing element aligns with a film
thickness monitor; and then (b) repeating step (a) until the measured film thickness reaches a predefined
thickness; and then (c) indicating that end point has been reached.
Claim 16
Dependent Claim
14 words
The invention of Claim 15, wherein the film thickness is measured by an
ellipsometer.
Claim 17
Dependent Claim
16 words
The invention of Claim 15, wherein the film thickness is measured by a beam
profile reflectometer.
Claim 18
Dependent Claim
16 words
The invention of Claim 15, wherein the film thickness is measured by a stress
pulse analyzer.
Claim 19
Dependent Claim
23 words
The invention of Claim 15 further comprising the step of terminating the
chemical-mechanical polishing process when the film thickness reaches a predefined
thickness.
Claim 20
Independent Claim
102 words
A method for determining removal rate per polishing element revolution at any
given circumference of a substrate while performing a chemical-mechanical polishing
process, the method comprising the steps of: (a) measuring a first film thickness of a substrate during a chemical-mechanical
polishing process when a monitoring channel in a polishing element aligns
with a film thickness monitor; and then (b) measuring a second film thickness ofa substrate during a chemical-mechanical
polishing process when the monitoring channel in a polishing element
realigns with the film thickness monitor, and then (c) calculating a difference between the second film thickness and the first
film thickness.
Claim 21
Dependent Claim
20 words
The invention of Claim 20, wherein the first film thickness and the second film
thickness are measured by an ellipsometer.
Claim 22
Dependent Claim
22 words
The invention of Claim 20, wherein the first film thickness and the second film
thickness are measured by a beam profile reflectometer.
Claim 23
Dependent Claim
22 words
The invention of Claim 20, wherein the first film thickness and the second film
thickness are measured by a stress pulse analyzer.
Claim 24
Independent Claim
210 words
A method for determining average removal rate per polishing element
revolution across a substrate surface while performing a chemical-mechanical polishing
process, the method comprising the steps of: (a) measuring a first film thickness of a substrate during a chemical-mechanical
polishing process when a first monitoring channel in a polishing element
aligns with a first film thickness monitor; and then (b) measuring a second film thickness of a substrate during a chemical-mechanical
polishing process when the first monitoring channel in a polishing element
realigns with the first film thickness monitor, and then (c) measuring a third film thickness of a substrate during a chemical-mechanical
polishing process when a second monitoring channel in a polishing element
aligns with a second film thickness monitor, and then (d) measuring a fourth film thickness of a substrate during a chemical-mechanical
polishing process when the second monitoring channel in a polishing
element realigns with the second film thickness monitor; and then (e) calculating a difference between the second film thickness of step (b)
and the first film thickness of step (a); and (f) calculating a difference between the fourth film thickness of step (d)
and the third film thickness of step (c); and then (g) calculating an average of the differences of steps (e) and (f).
Claim 25
Dependent Claim
19 words
The invention of Claim 24, wherein the first, second, third, and fourth film
thicknesses are measured by an ellipsometer.
Claim 26
Dependent Claim
21 words
The invention of Claim 24, wherein the first, second, third, and fourth film
thicknesses are measured by a beam profile reflectometer.
Claim 27
Dependent Claim
21 words
The invention of Claim 24, wherein the first, second, third, and fourth film
thicknesses are measured by a stress pulse analyzer.
Claim 28
Independent Claim
210 words
A method for determining removal rate variation per polishing element
revolution across a substrate surface while performing a chemical-mechanical polishing
process, the method comprising the steps of: (a) measuring a first film thickness of a substrate during a chemical-mechanical
polishing process when a first monitoring channel in a polishing element
aligns with a first film thickness monitor; and then (b) measuring a second film thickness of a substrate during a chemical-mechanical
polishing process when the first monitoring channel in a polishing element
realigns with the first film thickness monitor; and then (c) measuring a third film thickness of a substrate during a chemical-mechanical
polishing process when a second monitoring channel in a polishing element
aligns with a second film thickness monitor; and then (d) measuring a fourth film thickness of a substrate during a chemical-mechanical
polishing process when the second monitoring channel in a polishing
element realigns with the second film thickness monitor; and then (e) calculating a difference between the second film thickness of step (b)
and the first film thickness of step (a); and (f) calculating a difference between the fourth film thickness of step (d)
and the third film thickness of step (c); and then (g) calculating a variation of the differences of steps (e) and (f).
Claim 29
Dependent Claim
19 words
The invention of Claim 28, wherein the first, second, third, and fourth film
thicknesses are measured by an ellipsometer.
Claim 30
Dependent Claim
21 words
The invention of Claim 28, wherein the first, second, third, and fourth film
thicknesses are measured by a beam profile reflectometer.
Claim 31
Dependent Claim
21 words
The invention of Claim 28, wherein the first, second, third, and fourth film
thicknesses are measured by a stress pulse analyzer.
Claim 32
Independent Claim
42 words
A method of optimizing a chemical-mechanical polishing process comprising
the steps of: (a) characterizing a polishing process to determine effects of processing
parameters; and then (b) determining removal rate; and then (c) adjusting the polishing process parameters to optimize the removal rate.
Claim 33
Dependent Claim
26 words
The invention of Claim 32 further comprising the steps of: (d) determining removal rate variation; and then (e) adjusting the polishing process parameters to optimize uniformity.
References Cited (Backward Citations)
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