US5660672A
Expired / Lapsed
US
⏱️ 0.0 years remaining
In-situ monitoring of conductive films on semiconductor wafers
Assignee: Ebara Corp
•
Filing: 1995-04-10
•
Granted: 1997-08-26
•
Expires: 2015-04-10
Abstract
Abstract The change in thickness of a film on an underlying body such as a semiconductor substrate is monitored in situ by inducing a current in the film, and as the thickness of the film changes (either increase or decrease), the changes in the current are detected. With a conductive film, eddy currents are induced in the film by a generating an alternating electromagnetic field with a sensor which includes a capacitor and an inductor.
Inventors
- 👤 Leping Li
- 👤 Steven George Barbee
- 👤 Arnold Halperin
- 👤 Tony Frederick Heinz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 01:34
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/10; G01B7/105
Claims Analysis
Total Claims: 66
Claim 1
Independent Claim
131 words
An apparatus for in-situ monitoring of chemical-mechanical polishing a conductive film on a front side of a semiconductor wafer using a tool including a metal wafer carrier which holds the wafer by a back side opposite the front side, comprising: a sensor positioned in the carrier proximate the back side of the wafer, the sensor including (a) an inductor for inducing a current in the film by producing an alternating electromagnetic field proximate the film, and (b) means for shaping the alternating electromagnetic field so that the field is unaffected by the carrier; a capacitor electrically coupled to the inductor; and detecting means for detecting a change in the current due to a change in the thickness of the film, the detecting means electrically coupled to the sensor and the capacitor.
Claim 2
Independent Claim
131 words
An apparatus for in-situ monitoring of chemical-mechanical polishing a conductive film on a front side of a semiconductor wafer using a tool including a metal wafer carrier which holds the wafer by a back side opposite the front side, comprising: a sensor positioned in the carrier proximate the back side of the wafer, the sensor including (a) an inductor for inducing a current in the film by producing an alternating electromagnetic field proximate the film, and (b) means for shaping the alternating electromagnetic field so that the field is unaffected by the carrier; a capacitor electrically coupled to the inductor; and detecting means for detecting a change in the current due to a change in the thickness of the film, the detecting means electrically coupled to the sensor and the capacitor.
Claim 3
Dependent Claim
12 words
The apparatus of claim 1 wherein the current is an eddy current.
Claim 4
Dependent Claim
15 words
The apparatus of claim 1 wherein the capacitor and the inductor are connected in parallel.
Claim 5
Dependent Claim
11 words
The apparatus of claim 1 wherein the sensor includes the capacitor.
Claim 6
Dependent Claim
19 words
The apparatus of claim 1 wherein the means for shaping the alternating electromagnetic field comprises a ferrite pot core.
Claim 7
Dependent Claim
17 words
The apparatus of claim 5 wherein the sensor is embedded in a means for strengthening the sensor.
Claim 8
Dependent Claim
22 words
The apparatus of claim 6 wherein the strengthening means comprises a phenolic tube and epoxy for sealing the sensor inside the tube.
Claim 9
Dependent Claim
25 words
The apparatus of claim 1 wherein the alternating electromagnetic field is produced by electrically exciting the sensor from an external source through an impedance means.
Claim 10
Dependent Claim
12 words
The apparatus of claim 8 wherein the impedance means is a resistor.
Claim 11
Dependent Claim
18 words
The apparatus of claim 8 wherein the impedance means is a combination of an inductor and a capacitor.
Claim 12
Dependent Claim
17 words
The apparatus of claim 8 wherein the external source is a sweep output from a spectrum analyzer.
Claim 13
Dependent Claim
17 words
The apparatus of claim 8 wherein the external source is a swept output from a function generator.
Claim 14
Dependent Claim
20 words
The apparatus of claim 1 wherein the thickness of the film is decreased by removing a portion of the film.
Claim 15
Dependent Claim
26 words
The apparatus of claim 13 wherein after the portion of the film has been removed, a remaining portion of the film entirely covers the semiconductor wafer.
Claim 16
Dependent Claim
23 words
The apparatus of claim 14 wherein after the portion of the film has been removed, the semiconductor wafer is at least partially exposed.
Claim 17
Dependent Claim
20 words
The apparatus of claim 1 wherein the semiconductor wafer further comprises at least one underlying film under the conductive film.
Claim 18
Dependent Claim
11 words
The apparatus of claim 16 wherein the underlying film is conductive.
Claim 19
Dependent Claim
30 words
The apparatus of claim 16 wherein the underlying film is a metal selected from the group of metals consisting of Cu, Cr, W, Al, Ta, Ti, TiN, and combinations thereof.
Claim 20
Dependent Claim
11 words
The apparatus of claim 16 wherein the underlying film is magnetic.
Claim 21
Dependent Claim
16 words
The apparatus of claim 16 wherein the underlying film is patterned into a semiconductor device structure.
Claim 22
Dependent Claim
16 words
The apparatus of claim 16 wherein the film is the same material as the underlying film.
Claim 23
Dependent Claim
24 words
The apparatus of claim 1 further comprising a metal polishing table for holding a polishing pad against which the wafer is held for polishing.
Claim 24
Dependent Claim
31 words
The apparatus of claim 22 wherein the metal polishing table has a shielding means on top of the table for limiting the penetration of the alternating electromagnetic field into the table.
Claim 25
Dependent Claim
13 words
The apparatus of claim 23 wherein the shielding means comprises a ferrite coating.
Claim 26
Dependent Claim
37 words
The apparatus of claim 1 wherein the detecting means detects the change in the current by monitoring a signal change in the sensor resulting from an impedance-change due to the change in thickness of the conductive film.
Claim 27
Dependent Claim
38 words
The apparatus of claim 1 wherein the detecting means detects the change in the current by monitoring a frequency shift associated with a resonant peak of the sensor due to the change in thickness of the conductive film.
Claim 28
Dependent Claim
32 words
The apparatus of claim 1 wherein a plurality of the sensors are located at different locations proximate the semiconductor wafer for monitoring the removal of the conductive film on the semiconductor wafer.
Claim 29
Dependent Claim
15 words
The apparatus of claim 27 wherein the plurality of sensors are electrically connected in series.
Claim 30
Dependent Claim
15 words
The apparatus of claim 27 wherein the plurality of sensors are electrically connected in parallel.
Claim 31
Dependent Claim
15 words
The apparatus of claim 27 wherein each sensor is set to a unique resonant frequency.
Claim 32
Dependent Claim
18 words
The apparatus of claim 30 wherein the resonant frequency of each sensor is determined by a unique inductance.
Claim 33
Dependent Claim
18 words
The apparatus of claim 30 wherein the resonant frequency of each sensor is determined by a unique capacitance.
Claim 34
Dependent Claim
33 words
The apparatus of claim 1 further comprising means for adjusting the rate of polishing at different locations on the semiconductor wafer, the adjusting means coupled to the tool and to the detecting means.
Claim 35
Independent Claim
139 words
An apparatus for in-situ monitoring of a process for changing the thickness of a conductive film from a front side of a semiconductor wafer using a tool including a metal wafer support means which supports the wafer by a back side opposite the front side, comprising: a sensor positioned in the support means proximate the back side of the wafer, the sensor including (a) an inductor for inducing a current in the film by producing an alternating electromagnetic field proximate the film, and (b) means for shaping the alternating electromagnetic field so that the field is unaffected by the support means; a capacitor electrically coupled to the inductor; and detecting means for detecting a change in the current due to a change in the thickness of the film, the detecting means electrically coupled to the sensor and the capacitor.
Claim 36
Independent Claim
139 words
An apparatus for in-situ monitoring of a process for changing the thickness of a conductive film from a front side of a semiconductor wafer using a tool including a metal wafer support means which supports the wafer by a back side opposite the front side, comprising: a sensor positioned in the support means proximate the back side of the wafer, the sensor including (a) an inductor for inducing a current in the film by producing an alternating electromagnetic field proximate the film, and (b) means for shaping the alternating electromagnetic field so that the field is unaffected by the support means; a capacitor electrically coupled to the inductor; and detecting means for detecting a change in the current due to a change in the thickness of the film, the detecting means electrically coupled to the sensor and the capacitor.
Claim 37
Dependent Claim
15 words
The apparatus of claim 34 wherein the thickness of the film is decreased by etching.
Claim 38
Dependent Claim
16 words
The apparatus of claim 34 wherein the thickness of the film is increased by electrochemical means.
Claim 39
Dependent Claim
16 words
The apparatus of claim 34 wherein the thickness of the film is increased by vapor deposition.
Claim 40
Dependent Claim
33 words
The apparatus of claim 34 further comprising means for stopping the change in thickness of the film when a desired thickness has been achieved, the stopping means electrically coupled to the detecting means.
Claim 41
Dependent Claim
12 words
The apparatus of claim 34 wherein the current is an eddy current.
Claim 42
Dependent Claim
15 words
The apparatus of claim 34 wherein the capacitor and the inductor are connected in parallel.
Claim 43
Dependent Claim
11 words
The apparatus of claim 34 wherein the sensor includes the capacitor.
Claim 44
Dependent Claim
19 words
The apparatus of claim 34 wherein the means for shaping the alternating electromagnetic field comprises a ferrite pot core.
Claim 45
Dependent Claim
25 words
The apparatus of claim 34 wherein the alternating electromagnetic field is produced by electrically exciting the sensor from an external source through an impedance means.
Claim 46
Dependent Claim
12 words
The apparatus of claim 43 wherein the impedance means is a resistor.
Claim 47
Dependent Claim
18 words
The apparatus of claim 43 wherein the impedance means is a combination of an inductor and a capacitor.
Claim 48
Dependent Claim
17 words
The apparatus of claim 43 wherein the external source is a sweep output from a spectrum analyzer.
Claim 49
Dependent Claim
17 words
The apparatus of claim 43 wherein the external source is a swept output from a function generator.
Claim 50
Dependent Claim
20 words
The apparatus of claim 34 wherein the thickness of the film is decreased by removing a portion of the film.
Claim 51
Dependent Claim
26 words
The apparatus of claim 48 wherein after the portion of the film has been removed, a remaining portion of the film entirely covers the semiconductor wafer.
Claim 52
Dependent Claim
23 words
The apparatus of claim 48 wherein after the portion of the film has been removed, the semiconductor wafer is at least partially exposed.
Claim 53
Dependent Claim
20 words
The apparatus of claim 34 wherein the semiconductor wafer further comprises at least one underlying film under the conductive film.
Claim 54
Dependent Claim
11 words
The apparatus of claim 51 wherein the underlying film is conductive.
Claim 55
Dependent Claim
30 words
The apparatus of claim 51 wherein the underlying film is a metal selected from the group of metals consisting of Cu, Cr, W, Al, Ta, Ti, TiN, and combinations thereof.
Claim 56
Dependent Claim
11 words
The apparatus of claim 51 wherein the underlying film is magnetic.
Claim 57
Dependent Claim
16 words
The apparatus of claim 51, wherein the underlying film is patterned into a semiconductor device structure.
Claim 58
Dependent Claim
16 words
The apparatus of claim 51 wherein the film is the same material as the underlying film.
Claim 59
Dependent Claim
38 words
The apparatus of claim 34 wherein the detecting means detects the change in the current by monitoring a signal change in the sensor resulting from an impedance change due to the change in thickness of the conductive film.
Claim 60
Dependent Claim
38 words
The apparatus of claim 34 wherein the detecting means detects the change in the current by monitoring a frequency shift associated with a resonant peak of the sensor due to the change in thickness of the conductive film.
Claim 61
Dependent Claim
31 words
The apparatus of claim 34 wherein a plurality of the sensors are located at different locations proximate the wafer foe monitoring the removal of the conductive film on the semiconductor wafer.
Claim 62
Dependent Claim
15 words
The apparatus of claim 59 wherein the plurality of sensors are electrically connected in series.
Claim 63
Dependent Claim
15 words
The apparatus of claim 59 wherein the plurality of sensors are electrically connected in parallel.
Claim 64
Dependent Claim
15 words
The apparatus of claim 59 wherein each sensor is set to a unique resonant frequency.
Claim 65
Dependent Claim
18 words
The apparatus of claim 62 wherein the resonant frequency of each sensor is determined by a unique inductance.
Claim 66
Dependent Claim
18 words
The apparatus of claim 62 wherein the resonant frequency of each sensor is determined by a unique capacitance.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-08-25 | 2001-02-24 | 2001-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-25 | 2005-02-24 | 2005-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-25 | 2009-02-24 | 2009-08-26 | $7700.00 | Window Closed / Lapsed |