US3628137A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for automatically determining spreading resistance, resistivity and impurity concentration in semiconductor bodies
Assignee: Westinghouse Electric Corp
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Filing: 1969-11-24
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Granted: 1971-12-14
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Expires: 1989-11-24
Abstract
Abstract Apparatus for and method of performing spreading resistance measurements on semiconductor wafers to quantitatively assess the electrical conductivity of the material of the wafer whether it be laterally on a surface to determine material homogeneity or traversely through the thickness of the wafer to obtain a profile of resistivity versus position. Means are provided in the apparatus for automatically computing the resistivity and/or the impurity concentration in the wafer from the resistance measurements obtained whereby plots of these latter parameters are made to show lateral variations in the material characteristics as well as showing the profile of resistivity and/or impurity concentration versus the distance from a reference plane of the sample.
Inventors
- 👤 Robert G Mazur
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:20
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/282; G01R31/2831; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/041; G01R1/00; G01R1/02; G01R1/06; G01R1/067; G01R1/06705
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
199 words
In apparatus for measuring the resistance between two electrically conductive members in electrical contact with a semiconductor body and for determining from the resistance measurement the resistivity and impurity concentration in that volume of the semiconductor body beneath each conductive member in contact with the body, the combination of, mechanical means for placing at least two electrically conductive members in electrical contact with a first surface of the semiconductor body; means for establishing a predetermined electrical potential between said electrically conductive members whereby an electrical current proportional to the electrical resistance of the semiconductor body will flow through the body between the members; means electrically connected to said electrically conductive members for producing a first electrical signal which varies as a function of the resistance presented to said electrical current by the volume of the semiconductor body between each of said electrically conductive members; logarithmic transfer circuit means responsive to said electrical signal, to produce a second electrical signal which is proportional to the resistivity and impurity concentration values for the material of said body between the electrically conductive members, and means responsive to said second type electrical signal for recording and storing said resistivity and impurity concentration values.
Claim 2
Dependent Claim
199 words
In apparatus for measuring the resistance between two electrically conductive members in electrical contact with a semiconductor body and for determining from the resistance measurement the resistivity and impurity concentration in that volume of the semiconductor body beneath each conductive member in contact with the body, the combination of, mechanical means for placing at least two electrically conductive members in electrical contact with a first surface of the semiconductor body; means for establishing a predetermined electrical potential between said electrically conductive members whereby an electrical current proportional to the electrical resistance of the semiconductor body will flow through the body between the members; means electrically connected to said electrically conductive members for producing a first electrical signal which varies as a function of the resistance presented to said electrical current by the volume of the semiconductor body between each of said electrically conductive members; logarithmic transfer circuit means responsive to said electrical signal, to produce a second electrical signal which is proportional to the resistivity and impurity concentration values for the material of said body between the electrically conductive members, and means responsive to said second type electrical signal for recording and storing said resistivity and impurity concentration values.
Claim 3
Dependent Claim
40 words
The apparatus of claim 1 including means responsive to said electrical signal to produce a third electrical signal which varies as a function of the logarithm of actual resistance of the volume of semiconductor material beneath the electrically conductive members.
Claim 4
Dependent Claim
221 words
The apparatus of claim 2 in which said mechanical means includes means for elevating said at least one electrically conductive member off said surface of said semiconductor body; means for moving said body beneath said at least one electrically conductive member through an incremental distance when said at least one electrically conductive member is elevated from said surface; and means for thereafter lowering said at least one electrically conductive member into an electrIcally conductive relationship with a new portion of said surface of said body of semiconductor material; and including means for producing a fourth type electrical signal which varies as a function of the movement of said body beneath said at least one electrically conductive member; an X-Y recorder responsive to said fourth type electrical signal which varies as a function of movement and also responsive to said third type electrical signal which varies as a function of resistance for plotting the resistance values at spaced points along the body versus movement of the body; and means responsive to said fourth type electrical signal and a fifth type electrical signal, which fifth type signal varies as a function of the resistivity of the volume of semiconductor material beneath each of the conductive members, for plotting the resistivity values at spaced points along said semiconductor body versus movement of said body.
Claim 5
Dependent Claim
61 words
The apparatus of claim 3 in which said X-Y recorder means, responsive to said fourth type electrical signal, is also responsive to a sixth type electrical signal, which signal varies as a function of the impurity concentration of the semiconductor material between the electrically conductive members, said X-Y recorder plotting impurity concentration versus movement at spaced points on said semiconductor body
Claim 6
Dependent Claim
33 words
The apparatus of claim 1 including an electronic computer, said computer determining the resistivity value between spaced points of said semiconductor body and generating said fourth type electrical signal proportional to said resistivity.
Claim 7
Dependent Claim
34 words
The apparatus of claim 1 including an electronic computer, said computer determining the resistivity value between spaced points of said semiconductor body and generating said second type electrical signal proportional to said resistivity value.
Claim 8
Dependent Claim
25 words
The apparatus of claim 4 including an electronic computer which functions as the means for producing said second, third, fifth and sixth type electrical signals.
Claim 9
Dependent Claim
197 words
A process for determining and producing a profile of the electrical resistance in at least a portion of a body of semiconductor material comprising the steps of: a. electrically contacting at least a first surface of a body of semiconductor material with at least one electrically conductive member in a predetermined sequential stepping electrical contacting procedure across the at least one surface; b. establishing a predetermined electrical potential between said at least one electrically conductive member and a second electrically conductive member in electrical contact with a surface of said body each time said at least one electrically conductive member is in electrical contact with at least one surface during the predetermined sequential stepping electrical contacting procedure thereby inducing an electrical current to flow between the electrically conductive members; c. determining the resistivity of the volume of semiconductor material of the body beneath each of the electrically conductive members; d. electronically comparing the determined resistivity of the volume of semiconductor material with a program of approximate resistivities for the same semiconductor material; and e. producing a physical representation of the actual resistivity of the semiconductor material of the body between each of the two electrically conductive members.
Claim 10
Dependent Claim
197 words
A process for determining and producing a profile of the electrical resistance in at least a portion of a body of semiconductor material comprising the steps of: a. electrically contacting at least a first surface of a body of semiconductor material with at least one electrically conductive member in a predetermined sequential stepping electrical contacting procedure across the at least one surface; b. establishing a predetermined electrical potential between said at least one electrically conductive member and a second electrically conductive member in electrical contact with a surface of said body each time said at least one electrically conductive member is in electrical contact with at least one surface during the predetermined sequential stepping electrical contacting procedure thereby inducing an electrical current to flow between the electrically conductive members; c. determining the resistivity of the volume of semiconductor material of the body beneath each of the electrically conductive members; d. electronically comparing the determined resistivity of the volume of semiconductor material with a program of approximate resistivities for the same semiconductor material; and e. producing a physical representation of the actual resistivity of the semiconductor material of the body between each of the two electrically conductive members.
Claim 11
Dependent Claim
51 words
The process of claim 8 including affixing a large area ohmic electrical contact to a surface of said body; and affixing the second electrically conductive member to said large area ohmic electrical contact prior to electrically contacting said at least a first surface with said at least one electrically conductive member.
Claim 12
Dependent Claim
20 words
The process of claim 9 including affixing the large area ohmic electrical contact to the first surface of the body.
Claim 13
Dependent Claim
103 words
The process of claim 8 including the steps prior to establishing a predetermined electrical potentiaL between the members of: affixing a pair of a plurality of pairs of ohmic electrical contacts to the first surface of the body at predetermined intervals, the distance between adjacent pairs of ohmic electrical contacts being equal to the distance said at least one electrically conductive member is predeterminedly sequentially stepped; and electrically contacting each ohmic electrical contact of each pair of plurality of ohmic electrical contacts simultaneously with two electrically conductive members in a predetermined sequential stepping electrical contacting procedure across the first surface of the body.
Claim 14
Dependent Claim
88 words
The process of claim 9 including the steps prior to establishing a predetermined electrical potential between the members of; affixing a plurality of ohmic electrical contacts to the first surface of the body at predetermined intervals, the distance between adjacent ohmic electrical contacts being equal to the distance said at least one electrically conductive member is predeterminedly sequentially stepped; and electrically contacting each ohmic electrical contact of the plurality of ohmic electrical contacts in a predetermined sequential stepping electrical contacting procedure across the first surface of the body.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-13 | 1975-06-14 | 1975-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-13 | 1979-06-14 | 1979-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-13 | 1983-06-14 | 1983-12-14 | $7700.00 | Window Closed / Lapsed |