US4510387A
Expired / Lapsed
US
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Ion micro-analysis
Assignee: Hitachi Ltd
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Filing: 1982-10-20
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Granted: 1985-04-09
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Expires: 2002-10-20
Abstract
Abstract In ion micro-analysis, intensity of at least one species of secondary ions is monitored, and a reference etching time required for etching an implanted depth of primary ions is determined from a profile of a secondary ion intensity signal. Analysis time is graduated on the basis of the reference etching time to represent an analysis signal with the scale of the depth. The primary ions are non-volatile and may be active ions which react with a specimen or metal ions. The analyzed depth can be found during the analysis to prevent unwanted analysis and assure rapid data processing.
Inventors
- 👤 Eiichi Izumi
- 👤 Hifumi Tamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:21
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/252
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
131 words
An ion micro-analyzer (IMA) in which the surface of a specimen is bombarded with a primary ion beam and secondary ions generated thereby are mass-analyzed, comprising: means for generating a primary ion beam and bombarding the surface of a specimen with the primary ion beam; means for detecting at least one species of secondary ions emitted from the specimen, and generating a monitoring signal corresponding to the species of secondary ions; means for processing the monitoring signal to provide a relation between an implanted depth of the primary ions and an etching time corresponding to the implanted depth on the basis of a profile of the monitoring signal; and means for providing an output indicative of a depth of an analyzed site in the specimen on the basis of said relation.
Claim 2
Dependent Claim
131 words
An ion micro-analyzer (IMA) in which the surface of a specimen is bombarded with a primary ion beam and secondary ions generated thereby are mass-analyzed, comprising: means for generating a primary ion beam and bombarding the surface of a specimen with the primary ion beam; means for detecting at least one species of secondary ions emitted from the specimen, and generating a monitoring signal corresponding to the species of secondary ions; means for processing the monitoring signal to provide a relation between an implanted depth of the primary ions and an etching time corresponding to the implanted depth on the basis of a profile of the monitoring signal; and means for providing an output indicative of a depth of an analyzed site in the specimen on the basis of said relation.
Claim 3
Dependent Claim
33 words
An ion micro-analyzer according to claim 1, wherein said processing means includes a processing circuit for detecting a mean position of distribution of primary ions implanted during an initial stage of the analysis.
Claim 4
Dependent Claim
28 words
An ion micro-analyzer according to claim 2 wherein said processing means includes a circuit for obtaining a time derivative of at least first order of the monitoring signal.
Claim 5
Dependent Claim
88 words
An ion micro-analyzer according to claim 1 wherein said processing means includes a circuit for detecting substantial saturation of the monitoring signal, a circuit for dividing a saturated level of the monitoring signal by a predetermined factor, a circuit for obtaining a reference analysis time at which the monitoring signal reaches the divided signal level, and said means for providing a depth output including a circuit for converting an analysis time into an analysis depth on the basis of the reference analysis time to produce a depth signal.
Claim 6
Dependent Claim
32 words
An ion micro-analyzer according to claim 1 wherein said detecting and generating means includes a detector for detecting intensity of secondary ions from those secondary ions not subjected to the mass analysis.
Claim 7
Dependent Claim
35 words
An ion micro-analyzer according to claim 1 wherein said detecting and generating means includes an integrator for integrating a signal representative of intensity of secondary ions subjected to the mass analysis with respect to mass.
Claim 8
Independent Claim
132 words
A method for mass-analysis, in which the surface of a specimen is bombarded with a primary ion beam and secondary ions generated thereby are mass-analyzed, comprising the steps of: bombarding the surface of a specimen with a beam of non-volatile primary ions which when implanted in the specimen, do not volatalize and stay in the specimen; detecting ion intensity of at least one species of the secondary ions emitted from the specimen, said secondary ion intensity having a time profile carrying information regarding an implanted depth of the primary ions; detecting from the time profile of said secondary ion intensity a relation between the primary ion implanted depth and an etching time corresponding thereto; and generating a signal representative of a depth of an analyzed site on the basis of said relation.
Claim 9
Independent Claim
132 words
A method for mass-analysis, in which the surface of a specimen is bombarded with a primary ion beam and secondary ions generated thereby are mass-analyzed, comprising the steps of: bombarding the surface of a specimen with a beam of non-volatile primary ions which when implanted in the specimen, do not volatalize and stay in the specimen; detecting ion intensity of at least one species of the secondary ions emitted from the specimen, said secondary ion intensity having a time profile carrying information regarding an implanted depth of the primary ions; detecting from the time profile of said secondary ion intensity a relation between the primary ion implanted depth and an etching time corresponding thereto; and generating a signal representative of a depth of an analyzed site on the basis of said relation.
Claim 10
Dependent Claim
30 words
A method for mass-analysis according to claim 7 wherein said step of detecting the relation including determining a time derivative of at least first order of said secondary ion intensity.
Claim 11
Dependent Claim
20 words
A method for mass-analysis according to claim 7 wherein said non-volatile ions comprise active ions which react with the specimen.
Claim 12
Dependent Claim
15 words
A method for mass-analysis according to claim 7 wherein said non-volatile ions comprise metal ions.
Claim 13
Dependent Claim
37 words
An ion micro-analyzer according to claim 1, wherein said detecting and generating means includes means for generating at least two different monitor signals and a switch for selecting one of said at least two different monitor signals.
Claim 14
Dependent Claim
31 words
An ion micro-analyzer according to claim 1, further comprising an immunity circuit for rendering the processing means insensitive to a change in the monitoring signal occurring within a predetermined time period.
Claim 15
Dependent Claim
24 words
An ion micro-analyzer according to claim 1, wherein said processing means includes a circuit for obtaining a second order derivative of the monitoring signal.
Claim 16
Dependent Claim
41 words
An ion micro-analyzer according to claim 13, wherein said processing means further includes a level detector means connected to the output of said second order derivative circuit for obtaining a point at which said second order derivative crosses a predetermined level.
Claim 17
Dependent Claim
37 words
An ion micro-analyzer according to claim 3, wherein said processing means further includes a level setter means for setting a level and a cross detector for detecting the point at which said time derivative crosses said level.
Claim 18
Dependent Claim
77 words
An ion micro-analyzer according to claim 1, wherein said processing means includes a derivative circuit for producing a first order derivative of the monitoring signal, a level setter means for setting a level, a crossing detector for detecting a pair of points at which said first order derivative crosses said level, register means for storing a pair of times at which said crossing detector generates outputs, and an averaging circuit for obtaining an average of said times.
Claim 19
Dependent Claim
129 words
An in-situ monitoring system for monitoring an etched depth of a specimen in an ion micro-analyzer which bombards the speciment with a primary ion beam and mass-analyzes secondary ions emitted from the specimen, comprising: secondary ion detector means for detecting secondary ions emitted from the specimen and producing a monitoring signal indicative of a profile of the time change in the intensity of the secondary ions; derivative circuit means for taking a time derivative of said monitoring signal; reference value circuit means for generating a reference value signal; time scale generator means for detecting a characteristic point in the profile of said monitoring signal, based on said derivative and said reference value, and for generating a time scale signal based on a time at which said characteristic point appears.
Claim 20
Dependent Claim
129 words
An in-situ monitoring system for monitoring an etched depth of a specimen in an ion micro-analyzer which bombards the speciment with a primary ion beam and mass-analyzes secondary ions emitted from the specimen, comprising: secondary ion detector means for detecting secondary ions emitted from the specimen and producing a monitoring signal indicative of a profile of the time change in the intensity of the secondary ions; derivative circuit means for taking a time derivative of said monitoring signal; reference value circuit means for generating a reference value signal; time scale generator means for detecting a characteristic point in the profile of said monitoring signal, based on said derivative and said reference value, and for generating a time scale signal based on a time at which said characteristic point appears.
Claim 21
Dependent Claim
31 words
An in-situ monitoring system according to claim 17, wherein said time scale generator means includes marker circuit means for repeatedly generating a marker signal at an interval determined by said time.
Claim 22
Dependent Claim
87 words
An in-situ monitoring system according to claim 17, wherein said characteristic point is at least one of (a) a point at which the monitoring signal relative to a saturation value takes a predetermined level, (b) a point at which the first order derivative of the monitoring signal takes a maximum, (c) a point at which the second order derivative of the monitoring signal becomes substantially zero, and (d) a mid-point of two points at which the first order derivative of the monitoring signal takes a predetermined level.
Claim 23
Dependent Claim
29 words
An in-situ monitoring system according to claim 17, further comprising display means for displaying the data of analysis with the time scale indicative of the depth in the specimen.
References Cited (Backward Citations)
US3894233A
Cited
US3881108A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-04-08 | 1988-10-08 | 1989-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-08 | 1992-10-08 | 1993-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-08 | 1996-10-08 | 1997-04-09 | $7700.00 | Window Closed / Lapsed |