US5270222A
Expired / Lapsed
US
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Method and apparatus for semiconductor device fabrication diagnosis and prognosis
Assignee: Texas Instruments Inc
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Filing: 1990-12-31
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Granted: 1993-12-14
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Expires: 2010-12-31
Abstract
Abstract A sensor (210) for diagnosis and prognosis of semiconductor device fabrication processes measures specular, scattered, and total surface reflectances and transmittances of semiconductor wafers (124). The sensor (210) comprises a sensor arm (212) and an opto-electronic control box (214), for directing coherent electromagnetic or optical energy in the direction of semiconductor wafer (124). Opto-electronic control box (214) includes circuitry for measuring the amounts of laser powers coherently reflected from and transmitted through the semiconductor wafer (124) surface and the amounts of electromagnetic powers scatter reflected from and transmitted through the semiconductor wafer (124) surface. The present invention determines specular, scattered, and total reflectance and transmittance as well as surface roughness values for semiconductor wafer (124) based on measurements of coherent and scatter reflected and transmitted laser powers. The sensor (210) of the present invention can also provide a go/no-go test of semiconductor fabrication process quality. A process control computer associates with the sensor (210) to respond to spectral reflectance and transmittance measurements yielding surface roughness and thickness measurements as well as diagnosis/prognosis analysis results and control signals.
Inventors
- 👤 Mehrdad M. Moslehi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:44
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/50; H10P72/57; B; B24; B24B; B24B37/00; B24B37/005; B24B37/013; G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0616; G01B11/30; G01B11/303; G03; G03F; G03F7/00; G03F7/70; G03F7/70483; H10P72/04; H10P72/0451; H10P72/0468; H10P72/06; H10P72/0604; H10P72/0612; H10P74/00; H10P74/23; H10P74/238; H10P74/20; H10P74/203
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
91 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic power in the direction of a semiconductor wafer; measuring the amount of electromagnetic power reflected from said semiconductor wafer; comparing said reflected electromagnetic energy to a reference value; measuring the amount of electromagnetic power coherently reflected from the semiconductor wafer; measuring the amount of electromagnetic power scatter reflected from the semiconductor wafer; and determining semiconductor surface roughness as a function of said electromagnetic power, said reflected electromagnetic power, and said scatter reflected electromagnetic power.
Claim 2
Independent Claim
91 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic power in the direction of a semiconductor wafer; measuring the amount of electromagnetic power reflected from said semiconductor wafer; comparing said reflected electromagnetic energy to a reference value; measuring the amount of electromagnetic power coherently reflected from the semiconductor wafer; measuring the amount of electromagnetic power scatter reflected from the semiconductor wafer; and determining semiconductor surface roughness as a function of said electromagnetic power, said reflected electromagnetic power, and said scatter reflected electromagnetic power.
Claim 3
Dependent Claim
42 words
The method of claim 1, further comprising the steps of: receiving said reflected electromagnetic power using a reflection sensor; and receiving said scatter reflected electromagnetic power using a scatter reflection sensor, including an imaging lens for focusing said scatter reflected electromagnetic power.
Claim 4
Dependent Claim
25 words
The method of claim 1, further comprising the step of calculating semiconductor wafer metal film thickness as a function of said semiconductor wafer surface roughness.
Claim 5
Dependent Claim
25 words
The method of claim 1, further comprising the step of calculating semiconductor wafer polycrystalline film thickness as a function of said semiconductor wafer surface roughness.
Claim 6
Dependent Claim
29 words
The method of claim 1, further comprising the step of comparing total spectral reflectivity for metal film versus metal film thickness for semiconductor wafer process diagnosis and prognosis analysis.
Claim 7
Independent Claim
98 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured portion of the reflected electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and wherein said measured portion can be either specular, scattered or total reflected electromagnetic power, and wherein said expected values can be of specular, scattered or total reflected electromagnetic power.
Claim 8
Independent Claim
98 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured portion of the reflected electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and wherein said measured portion can be either specular, scattered or total reflected electromagnetic power, and wherein said expected values can be of specular, scattered or total reflected electromagnetic power.
Claim 9
Independent Claim
131 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured portion of the reflected electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and controlling a semiconductor wafer fabrication process in response to said comparison of said measured portion of the reflected electromagnetic power to said expected values for reflected electromagnetic powers, wherein said measured portion of the reflected electromagnetic power can be either specular, scattered, or total reflected electromagnetic power, and wherein said expected values can be of specular, scattered, or total reflected electromagnetic power.
Claim 10
Independent Claim
131 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured portion of the reflected electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and controlling a semiconductor wafer fabrication process in response to said comparison of said measured portion of the reflected electromagnetic power to said expected values for reflected electromagnetic powers, wherein said measured portion of the reflected electromagnetic power can be either specular, scattered, or total reflected electromagnetic power, and wherein said expected values can be of specular, scattered, or total reflected electromagnetic power.
Claim 11
Independent Claim
83 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and wherein said electromagnetic energy source comprises a coherent laser energy source which emits a 1.3 μm wavelength signal.
Claim 12
Independent Claim
83 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and wherein said electromagnetic energy source comprises a coherent laser energy source which emits a 1.3 μm wavelength signal.
Claim 13
Independent Claim
83 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and wherein said electromagnetic energy source comprises a coherent laser energy source which emits a 1.55 μm wavelength signal.
Claim 14
Independent Claim
83 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and wherein said electromagnetic energy source comprises a coherent laser energy source which emits a 1.55 μm wavelength signal.
Claim 15
Independent Claim
110 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and measuring the amount of electromagnetic power coherently reflected from the semiconductor wafer; measuring the amount of electromagnetic power scatter reflected from the semiconductor wafer; and determining semiconductor wafer surface roughness based on measurements of said coherently reflected electromagnetic power, and said scatter reflected electromagnetic power.
Claim 16
Independent Claim
110 words
A method for diagnosis and prognosis of semiconductor wafer fabrication processes, comprising the steps of: directing electromagnetic energy in the direction of a semiconductor wafer; measuring at least a portion of the electromagnetic power reflected from said semiconductor wafer; comparing said measured electromagnetic power to reference values, said reference values comprising expected values for reflected electromagnetic powers for a given semiconductor wafer film thickness; and measuring the amount of electromagnetic power coherently reflected from the semiconductor wafer; measuring the amount of electromagnetic power scatter reflected from the semiconductor wafer; and determining semiconductor wafer surface roughness based on measurements of said coherently reflected electromagnetic power, and said scatter reflected electromagnetic power.
Claim 17
Dependent Claim
55 words
The method of claim 10, further comprising the steps of receiving said coherently reflected electromagnetic power using a coherent reflection sensor; and receiving said scatter reflected electromagnetic power using a scatter reflection sensor, including an imaging lens for focusing said scatter reflected electromagnetic power, and an imaging lens for focusing said coherently reflected electromagnetic power.
Claim 18
Dependent Claim
25 words
The method of claim 10, further comprising the step of calculating semiconductor wafer metal film thickness as a function of said semiconductor wafer surface roughness.
Claim 19
Dependent Claim
25 words
The method of claim 10, further comprising the step of calculating semiconductor wafer polycrystalline film thickness as a function of said semiconductor wafer surface roughness.
Claim 20
Dependent Claim
34 words
The method of claim 10, further comprising the step of determining specular, scattered, and total spectral reflectivity for metal film versus metal film thickness and scattering parameter for semiconductor wafer processing diagnosis and prognosis.
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