US5798649A
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US
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Method for detecting defects in semiconductor insulators
Assignee: Texas Instruments Inc
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Filing: 1993-08-19
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Granted: 1998-08-25
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Expires: 2013-08-19
Abstract
Abstract The reliability of thin film insulators is determined with noise measurements which find the barrier height mean and standard deviation. A constant voltage source is applied across the thin film insulator. A low noise amplifier is connected across a resistor which is in series with the insulator. A spectrum analyzer is connected to the low noise amplifier. The power density is obtained by observing the output of a spectrum analyzer. The current spectral density is compared to a predetermined reference to detect the presence of defects in the insulator.
Inventors
- 👤 Michael C. Smayling
- 👤 Klaus A. Anselm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:02
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/50; G01R31/64
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
119 words
A method for manufacturing an integrated circuit, comprising the steps of: providing a device known to be reliable which includes an insulator formed on a semiconductor region; testing said device known to be reliable to determine a reference current spectral density; providing one or more semiconductor substrates to be processed; processing said one or more substrates, the processing step including the step of forming an insulator on a semiconductor region; and evaluating said insulator, the step of evaluating comprising the steps of: applying voltage across said insulator; measuring currents induced by said voltage; determining current spectral density of the measured currents; and detecting the presence of defects in the insulator by comparing said current spectral density to said reference.
Claim 2
Independent Claim
119 words
A method for manufacturing an integrated circuit, comprising the steps of: providing a device known to be reliable which includes an insulator formed on a semiconductor region; testing said device known to be reliable to determine a reference current spectral density; providing one or more semiconductor substrates to be processed; processing said one or more substrates, the processing step including the step of forming an insulator on a semiconductor region; and evaluating said insulator, the step of evaluating comprising the steps of: applying voltage across said insulator; measuring currents induced by said voltage; determining current spectral density of the measured currents; and detecting the presence of defects in the insulator by comparing said current spectral density to said reference.
Claim 3
Independent Claim
102 words
A method for manufacturing an integrated circuit, comprising the steps of: determining a reference current spectral density; providing one or more semiconductor substrates to be processed; processing said one or more substrates, the processing step including the step of forming, on each of said substrates, an insulator and a conductor; and evaluating said insulator, the step of evaluating comprising the steps of: applying voltage across said insulator; measuring currents induced by said voltage; determining current spectral density of the measured currents; and determining the presence of defects in the insulator by comparing said current spectral density to said reference current spectral density.
Claim 4
Independent Claim
102 words
A method for manufacturing an integrated circuit, comprising the steps of: determining a reference current spectral density; providing one or more semiconductor substrates to be processed; processing said one or more substrates, the processing step including the step of forming, on each of said substrates, an insulator and a conductor; and evaluating said insulator, the step of evaluating comprising the steps of: applying voltage across said insulator; measuring currents induced by said voltage; determining current spectral density of the measured currents; and determining the presence of defects in the insulator by comparing said current spectral density to said reference current spectral density.
Claim 5
Independent Claim
62 words
A method for detecting defects in an insulator on a semiconductor device, comprising the steps of: determining a reference current spectral density; applying voltage across said insulator; measuring currents induced by said voltage; determining current spectral density of the measured currents; and determining the presence of defects in the insulator by comparing said current spectral density to said reference current spectral density.
Claim 6
Independent Claim
62 words
A method for detecting defects in an insulator on a semiconductor device, comprising the steps of: determining a reference current spectral density; applying voltage across said insulator; measuring currents induced by said voltage; determining current spectral density of the measured currents; and determining the presence of defects in the insulator by comparing said current spectral density to said reference current spectral density.
Claim 7
Dependent Claim
26 words
The method of claim 3 wherein the step of applying voltage includes applying an electric field in the range of four to twelve megavolts per centimeter.
Claim 8
Dependent Claim
33 words
The method of claim 3 wherein the step of comparing the current spectral density to said reference current spectral density includes comparing within a frequency range of from one-tenth hertz to 1.2 megahertz.
Claim 9
Dependent Claim
34 words
The method of claim 3 wherein the step of comparing the current spectral density to said reference current spectral density includes comparing within a frequency range of from one-tenth hertz to one hundred hertz.
Claim 10
Dependent Claim
19 words
The method of claim 5 wherein the step of comparing above 10 kilohertz is done with a burst detector.
Claim 11
Independent Claim
28 words
The method of either claims 5 or 6, wherein, in addition, a burst detector detects current fluctuations greater than 1% of the running average of the DC current.
Claim 12
Dependent Claim
23 words
The method of claim 3 wherein said semiconductor device comprises a MOS structure which has a gate edge over a thin oxide insulator.
Claim 13
Dependent Claim
23 words
The method of claim 3 wherein said semiconductor device comprises a MOS structure which has a gate edge over a thick oxide insulator.
Claim 14
Dependent Claim
25 words
The method of claim 3 wherein said semiconductor device comprises a MOS structure which has corners in the gate pattern over a thin oxide insulator.
Claim 15
Dependent Claim
25 words
The method of claim 3 wherein said semiconductor device comprises a MOS structure which has corners in the gate pattern over a thick oxide insulator.
Claim 16
Independent Claim
76 words
A system containing a semiconductor memory device, the memory device having been tested for reliability by testing for defects in insulators on the memory device, the testing comprising the steps of: a. applying voltage across the insulator to be tested; b. measuring currents induced by the voltage; c. determining current spectral density of the measured currents; and d. comparing the current spectral density to a predetermined reference for detecting the presence of defects in the insulator.
Claim 17
Independent Claim
76 words
A system containing a semiconductor memory device, the memory device having been tested for reliability by testing for defects in insulators on the memory device, the testing comprising the steps of: a. applying voltage across the insulator to be tested; b. measuring currents induced by the voltage; c. determining current spectral density of the measured currents; and d. comparing the current spectral density to a predetermined reference for detecting the presence of defects in the insulator.
Claim 18
Dependent Claim
26 words
The system of claim 13 wherein the step of applying voltage includes applying an electric field in the range of four to twelve megavolts per centimeter.
Claim 19
Dependent Claim
31 words
The system of claim 13 wherein the step of comparing the current spectral density to a predetermined reference includes comparing within a frequency range of from one-tenth hertz to 1.2 megahertz.
Claim 20
Dependent Claim
32 words
The system of claim 13 wherein the step of comparing the current spectral density to a predetermined reference includes comparing within a frequency range of from one-tenth hertz to one hundred hertz.
Claim 21
Independent Claim
118 words
A method for designing an integrated circuit, comprising: a. selecting a plurality of possible structures; b. for each structure, providing one or more semiconductor substrates to be processed; c. processing the substrates, the processing step including the step of forming an insulator on substrates; d. evaluating the insulator, the step of evaluating comprising: i. applying voltage across the insulator; ii. measuring currents induced by the voltage; iii. determining current spectral density of the measured currents; and iv. comparing the current spectral density to a predetermined reference for detecting the presence of defects in the insulator; and e. for each structure, comparing the results from the evaluating step with the results from the evaluating step for the other structures.
Claim 22
Independent Claim
118 words
A method for designing an integrated circuit, comprising: a. selecting a plurality of possible structures; b. for each structure, providing one or more semiconductor substrates to be processed; c. processing the substrates, the processing step including the step of forming an insulator on substrates; d. evaluating the insulator, the step of evaluating comprising: i. applying voltage across the insulator; ii. measuring currents induced by the voltage; iii. determining current spectral density of the measured currents; and iv. comparing the current spectral density to a predetermined reference for detecting the presence of defects in the insulator; and e. for each structure, comparing the results from the evaluating step with the results from the evaluating step for the other structures.
Claim 23
Dependent Claim
26 words
The method of claim 17 wherein the step of applying voltage includes applying an electric field in the range of four to twelve megavolts per centimeter.
Claim 24
Dependent Claim
31 words
The method of claim 17 wherein the step of comparing the current spectral density to a predetermined reference includes comparing within a frequency range of from one-tenth hertz to 1.2 megahertz.
Claim 25
Dependent Claim
32 words
The method of claim 17 wherein the step of comparing the current spectral density to a predetermined reference includes comparing within a frequency range of from one-tenth hertz to one hundred hertz.
Claim 26
Dependent Claim
71 words
The method of claim 3 wherein said step of determining a reference current spectral density comprising the steps of: providing a test device known to be reliable, said test device fabricated in a manner substantially the same as said semiconductor device; applying a test voltage across an insulator on said test device; measuring test currents induced by said test voltage; and determining said reference current spectral density from said test currents.
References Cited (Backward Citations)
US5049811A
Cited
US5057441A
Cited
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