EP0451514A2
Expired / Lapsed
EP
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Measurement of conductive layers of a semiconductor wafer
Assignee: Texas Instruments Inc
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Filing: 1991-03-11
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Granted: —
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Expires: 2011-03-11
Abstract
Abstract A non-invasive sensor system (50) for real-time in situ measurements of sheet resistance and thickness of conductive layers of a semiconductor wafer. The sensor (50) includes a microwave source (78) for generating a plurality of microwave signals. An emitter waveguide (52) receives the plurality of microwave signals from the microwave source (78) and emits the microwave signals in the direction of the semiconductor wafer (20) in fabrication chamber (18). The collector waveguide (84) detects the reflected microwave signals from the semiconductor wafer (20). A dual directional coupler (64) communicates with emitter waveguide (52) to direct the microwave signals to and from the emitter waveguide (52) and to generate a plurality of electrical signals that relate to semiconductor wafer (20), conductive layer (108), and deposition vapor physical characteristics. These physical characteristics include conductive layer thickness, resistivity, and substrate temperature. An alternative embodiment provides measurements of plasma vapor density and other interferometric parameters.
Inventors
- 👤 Mehrdad M. Moslehi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 05:41
CPC Classifications
H; H10; H10P; H10P74/00; H10P74/20; H10P74/203; G; G01; G01D; G01D5/00; G01D5/48; G01B; G01B15/00; G01B15/02; G01K; G01K11/00; H10P74/207; H10P74/27
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
147 words
An apparatus for non-invasive, real-time, in situ measurement of conductive layers of a semiconductor wafer in a fabrication chamber, comprising: an electromagnetic signal source for generating electromagnetic waves; an emitter waveguide in communication with said electromagnetic wave source and deposition chamber for emitting said electromagnetic waves through the chamber and toward the semiconductor wafer, said emitter waveguide also for detecting a portion of electromagnetic waves reflected from the semiconductor wafer; at least one coupler in communication with said emitter waveguide for generating a plurality of electrical signals, said plurality of electrical signals comprising an emitted set of electrical signals proportional to the power of said electromagnetic waves that the semiconductor wafer reflects, said plurality of electrical signals from said at least one coupler being directly related to measurements of the semiconductor wafer conductive layer; and circuitry for converting said plurality of electrical signals into conductive layer measurements.
Claim 2
Dependent Claim
30 words
Apparatus according to Claim 1, wherein said at least one coupler comprises a dual directional coupler for communicating among said electromagnetic wave source, said emitter waveguide, and said measuring circuitry.
Claim 3
Dependent Claim
62 words
Apparatus according to Claim 1 or Claim 2, wherein said electromagnetic waves have a frequency range bounded by a lower frequency and an upper frequency, said lower frequency producing a signal wavelength that is small relative to the dimensions of the semiconductor wafer and said upper frequency providing for optimal measurement sensitivity to electromagnetic wave interaction to be with the conductive layer.
Claim 4
Dependent Claim
29 words
Apparatus according to any preceding claim, wherein said emitter waveguide further comprises a microwave transmitter for transmitting said electromagnetic waves and a microwave detector for detecting said electromagnetic waves.
Claim 5
Dependent Claim
19 words
Apparatus according to any preceding claim, further comprising, a collector waveguide for collecting a portion of said electromagnetic waves.
Claim 6
Dependent Claim
23 words
Apparatus according to any preceding claim, wherein said electromagnetic wave source comprises a low frequency solid state frequency source capable of frequency scanning.
Claim 7
Dependent Claim
27 words
Apparatus according to any preceding claim, further comprising a microwave signal chopper within said electromagnetic wave source for electronically chopping said electromagnetic waves to improve signal-to-noise ratios.
Claim 8
Dependent Claim
23 words
Apparatus according to any preceding claim, further comprising a plurality of detectors for measuring a predetermined aspect of said portion of electromagnetic waves.
Claim 9
Dependent Claim
30 words
Apparatus according to any preceding claim, further comprising a process control computer for calculating conductive layer electromagnetic wave reflectance measurements as a function of said emitted and reflected electromagnetic waves.
Claim 10
Dependent Claim
74 words
Apparatus according to any preceding Claim 9, a plurality of electronically recorded look-up table within said computer for automatically converting semiconductor wafer electromagnetic wave reflectance measurements into one or more of the following: a) conductive film physical property measurements; b) conductive layer thickness and sheet measurements during etch processing of a semiconductor wafer in said fabrication chamber; c) semiconductor substrate dopant levels; d) semiconductor wafer temperature measurements; e) plasma vapor electromagnetic wave interaction measurements.
Claim 11
Independent Claim
108 words
A method for performing non-invasive real-time in situ semiconductor wafer conductive layer measurements in a fabrication chamber, comprising the steps of: generating electromagnetic waves; emitting said electromagnetic waves within the fabrication chamber toward the semiconductor wafer; detecting a portion of said electromagnetic waves that the semiconductor wafer reflects within the deposition chamber; generating a plurality of electrical signals, said plurality of electrical signals comprising an emitted set of electrical signals proportional to said electromagnetic waves that the semiconductor wafer reflects, said plurality of electrical signals being directly related to the semiconductor wafer conductive layer measurements; and converting said plurality of electrical signals into semiconductor wafer conductive layer measurements.
Claim 12
Dependent Claim
15 words
The method of Claim 11, further comprising the step of electronically chopping said electromagnetic waves.
Claim 13
Dependent Claim
39 words
The method of Claim 11 or Claim 12, wherein said step of generating a plurality of electrical signals further comprises the step of producing DC voltages proportional to said emitted set of signals and said reflected set of signals.
Claim 14
Independent Claim
43 words
The method of any of Claims 11-13, wherein the semiconductor wafer contains a patterned conductive layer formed by etching from said conductive layer and said converting step further comprises the step of converting said plurality of electrical signals into etching end-point detection measurements.
Claim 15
Independent Claim
28 words
The method of any of Claims 11-14, wherein said detecting step further comprises the step of detecting said portion of reflected electromagnetic waves at different deposition process temperatures.
Claim 16
Independent Claim
32 words
The method of any of Claims 11-15, further comprising one or both of the steps of converting said plurality of signals to: a) semiconductor substrate dopant levels; b) semiconductor wafer temperature measurements.
References Cited (Backward Citations)
No citation records indexed.
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