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Patent US5277769A successfully refreshed from Google Patents.
US5277769A
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Electrochemical thinning of silicon
Assignee: United States Department of Energy
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Filing: 1991-11-27
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Granted: 1994-01-11
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Expires: 2011-11-27
Abstract
Abstract Porous semiconducting material, e.g. silicon, is formed by electrochemical treatment of a specimen in hydrofluoric acid, using the specimen as anode. Before the treatment, the specimen can be masked. The porous material is then etched with a caustic solution or is oxidized, depending of the kind of structure desired, e.g. a thinned specimen, a specimen, a patterned thinned specimen, a specimen with insulated electrical conduits, and so on. Thinned silicon specimen can be subjected to tests, such as measurement of interstitial oxygen by Fourier transform infra-red spectroscopy (FTIR).
Inventors
- 👤 John W. Medernach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:13
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/61; H10P50/613; C; C25; C25F; C25F3/00; C25F3/02; C25F3/12; H10P50/64; H10P50/642; H10P50/644; Y; Y10; Y10T; Y10T428/00; Y10T428/21; Y10T428/216; Y10T428/218
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
96 words
A method for preparing a semiconductor specimen, comprising the steps of: defining a region on a surface of a semiconductor specimen that is resistant to electrochemical action and defining a region on the surface of the semiconductor specimen that is susceptible to electrochemical action, subjecting the semiconductor specimen to electrochemical action, wherein the semiconductor specimen serves as an anode, such that porous semiconductor material is formed in the defined region that is susceptible to electrochemical action, and removing the porous semiconductor material from the semiconductor specimen, leaving a portion of the semiconductor specimen that is thinned.
Claim 2
Independent Claim
96 words
A method for preparing a semiconductor specimen, comprising the steps of: defining a region on a surface of a semiconductor specimen that is resistant to electrochemical action and defining a region on the surface of the semiconductor specimen that is susceptible to electrochemical action, subjecting the semiconductor specimen to electrochemical action, wherein the semiconductor specimen serves as an anode, such that porous semiconductor material is formed in the defined region that is susceptible to electrochemical action, and removing the porous semiconductor material from the semiconductor specimen, leaving a portion of the semiconductor specimen that is thinned.
Claim 3
Dependent Claim
34 words
The method of claim 1, wherein said porous semiconductor material is formed by subjecting said semiconductor specimen to electrochemical action in an ethanolic hydrofluoric acid bath in which the specimen serves as an anode.
Claim 4
Dependent Claim
18 words
The method of claim 1, wherein the porous semiconductor material formed is chemically removed, leaving a thinned specimen.
Claim 5
Dependent Claim
17 words
The method of claim 3, wherein the porous material is removed by subjection to an oxidizing atmosphere.
Claim 6
Dependent Claim
27 words
The process of claim 4 wherein the porous material is removed by subjection to oxygen at a temperature within the range of about 600° to 900° C.
Claim 7
Dependent Claim
13 words
The method of claim 1, wherein the specimen is an integrated circuit chip.
Claim 8
Dependent Claim
13 words
The method of claim 1, wherein the semiconductor specimen is heavily doped silicon.
Claim 9
Dependent Claim
12 words
The method of claim 1 wherein the semiconductor specimen is gallium arsenide.
Claim 10
Dependent Claim
31 words
The method of claim 1, wherein the region of the surface of the semiconductor specimen that is resistant to electrochemical action is defined by an inert portion of an electrochemical cell.
Claim 11
Dependent Claim
27 words
The method of claim 1, wherein the region of the surface of the semiconductor specimen that is resistant to electrochemical action is defined by conventional masking techniques.
Claim 12
Dependent Claim
38 words
The method of claim 1, further including the step of permitting the semiconductor specimen to equilibrate for a predetermined period of time after subjection to electrochemical action but before removing the porous semiconductor material from the semiconductor specimen.
Claim 13
Dependent Claim
15 words
The method of claim 1, wherein the porous silicon is removed by a caustic solution.
Claim 14
Dependent Claim
25 words
The method of claim 1, wherein the semiconductor specimen is made from heavily doped silicon having dopant concentrations greater than 10 17 /cm 3 .
Claim 15
Dependent Claim
17 words
The method of claim 1, wherein the semiconductor specimen is prepared for Fourier transform infrared spectroscopy (FTIR).
Claim 16
Independent Claim
119 words
A method for preparing a silicon specimen, comprising the steps of: defining a region on a surface of a silicon specimen that is resistant to electrochemical action and defining a region on the surface of the silicon specimen that is susceptible to electrochemical action, subjecting the silicon specimen to electrochemical action, wherein the silicon specimen serves as an anode, such that porous silicon material is formed in the defined region that is susceptible to electrochemical action, permitting the silicon specimen to equilibrate for a predetermined period of time after formation of the porous silicon material, and removing the porous silicon material from the silicon specimen with a caustic solution, leaving a portion of the silicon specimen that is thinned.
Claim 17
Independent Claim
119 words
A method for preparing a silicon specimen, comprising the steps of: defining a region on a surface of a silicon specimen that is resistant to electrochemical action and defining a region on the surface of the silicon specimen that is susceptible to electrochemical action, subjecting the silicon specimen to electrochemical action, wherein the silicon specimen serves as an anode, such that porous silicon material is formed in the defined region that is susceptible to electrochemical action, permitting the silicon specimen to equilibrate for a predetermined period of time after formation of the porous silicon material, and removing the porous silicon material from the silicon specimen with a caustic solution, leaving a portion of the silicon specimen that is thinned.
Claim 18
Dependent Claim
119 words
A silicon specimen made by a method comprising the steps of: defining a region on a surface of a silicon specimen that is resistant to electrochemical action and defining a region on the surface of the silicon specimen that is susceptible to electrochemical action, subjecting the silicon specimen to electrochemical action, wherein the silicon specimen serves as an anode, such that porous silicon material is formed in the defined region that is susceptible to electrochemical action, permitting the silicon specimen to equilibrate for a predetermined period of time after formation of the porous silicon material, and removing the porous silicon material from the silicon specimen with a caustic solution, leaving a portion of the silicon specimen that is thinned.
Claim 19
Dependent Claim
119 words
A silicon specimen made by a method comprising the steps of: defining a region on a surface of a silicon specimen that is resistant to electrochemical action and defining a region on the surface of the silicon specimen that is susceptible to electrochemical action, subjecting the silicon specimen to electrochemical action, wherein the silicon specimen serves as an anode, such that porous silicon material is formed in the defined region that is susceptible to electrochemical action, permitting the silicon specimen to equilibrate for a predetermined period of time after formation of the porous silicon material, and removing the porous silicon material from the silicon specimen with a caustic solution, leaving a portion of the silicon specimen that is thinned.
Claim 20
Independent Claim
117 words
A method of measuring interstitial oxygen in a semiconductor specimen, comprising the steps of: defining a region on a surface of the semiconductor specimen that is resistant to electrochemical action and defining a region on the surface of the semiconductor specimen that is susceptible to electrochemical action, subjecting the semiconductor specimen to electrochemical action, wherein the semiconductor specimen serves as an anode, such that porous semiconductor material is formed in the defined region that is susceptible to electrochemical action, removing the porous semiconductor material from the semiconductor specimen, leaving a portion of the semiconductor specimen that is thinned, and determining interstitial oxygen by subjecting the thinned portion of the semiconductor specimen to Fourier transform infra-red spectroscopy (FTIR).
Claim 21
Independent Claim
117 words
A method of measuring interstitial oxygen in a semiconductor specimen, comprising the steps of: defining a region on a surface of the semiconductor specimen that is resistant to electrochemical action and defining a region on the surface of the semiconductor specimen that is susceptible to electrochemical action, subjecting the semiconductor specimen to electrochemical action, wherein the semiconductor specimen serves as an anode, such that porous semiconductor material is formed in the defined region that is susceptible to electrochemical action, removing the porous semiconductor material from the semiconductor specimen, leaving a portion of the semiconductor specimen that is thinned, and determining interstitial oxygen by subjecting the thinned portion of the semiconductor specimen to Fourier transform infra-red spectroscopy (FTIR).
Claim 22
Dependent Claim
26 words
The method of claim 17, wherein the silicon specimen is allowed to equilibrate for a predetermined period of time after formation of the porous silicon material.
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