US5547896A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct etch for thin film resistor using a hard mask
Assignee: Intersil Corp
•
Filing: 1995-02-13
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Granted: 1996-08-20
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Expires: 2015-02-13
Abstract
Abstract In a method of etching a thin film resistor material, such as NiCr or CrSi, and of producing a thin film resistor, a non-photoresist hard mask is deposited on an exposed surface of thin film resistor material, a delineated portion of the hard mask is etched with a hydrogen peroxide etchant that does not affect the thin film resistor material to expose the material therebeneath, and the exposed thin film resistor material is etched with a second etchant that does not affect the hard mask. The second etchant may be sulfuric acid heated to greater than 125° C. for NiCr or a mixture of phosphoric acid, nitric acid and hydrofluoric acid for CrSi. The hard mask preferably comprises TiW.
Inventors
- 👤 Jack H. Linn
- 👤 John T. Gasner
- 👤 Stephen J. Gaul
- 👤 Chris A. McCarty
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:24
CPC Classifications
H; H10; H10P; H10P76/00; H10P76/40; H10P76/405; H10D; H10D1/00; H10D1/40; H10D1/47; H10D1/474; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667; H10P50/71; H10P76/408; H10P76/4085; Y; Y10; Y10S; Y10S148/00; Y10S148/136
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
129 words
A method of etching a thin film resistor in a semiconductor device comprising the steps of: (a) depositing a thin film resistor material on a substrate and depositing a non-photoresist hard mask on an exposed surface of the thin film resistor material in a deposition chamber without breaking a vacuum in the deposition chamber; (b) etching a delineated portion of the hard mask with a first etchant that does not affect the thin film resistor material to expose the material therebeneath; and (c) wet etching the exposed thin film resistor material with a second etchant that does not affect the hard mask; and (d) etching the remaining hard mask except the portions of the hard mask overlying selected portions of the thin film resistor material for contacting electrical interconnects.
Claim 2
Independent Claim
129 words
A method of etching a thin film resistor in a semiconductor device comprising the steps of: (a) depositing a thin film resistor material on a substrate and depositing a non-photoresist hard mask on an exposed surface of the thin film resistor material in a deposition chamber without breaking a vacuum in the deposition chamber; (b) etching a delineated portion of the hard mask with a first etchant that does not affect the thin film resistor material to expose the material therebeneath; and (c) wet etching the exposed thin film resistor material with a second etchant that does not affect the hard mask; and (d) etching the remaining hard mask except the portions of the hard mask overlying selected portions of the thin film resistor material for contacting electrical interconnects.
Claim 3
Dependent Claim
31 words
The method of claim 1 where the thin film resistor material comprises NiCr and wherein the hard mask comprises one of TiW and molybdenum and the first etchant comprises hydrogen peroxide.
Claim 4
Dependent Claim
19 words
The method of claim 2 wherein the second etchant is sulfuric acid at a temperature greater than 125° C.
Claim 5
Dependent Claim
31 words
The method of claim 1 where the thin film resistor material comprises CrSi and wherein the hard mask comprises one of TiW and molybdenum and the first etchant comprises hydrogen peroxide.
Claim 6
Dependent Claim
20 words
The method of claim 4 wherein the second etchant is a mixture of phosphoric acid, nitric acid and hydrofluoric acid.
Claim 7
Dependent Claim
19 words
The method of claim 1 further comprising the step of depositing electrical interconnects on the remaining hard mask portions.
Claim 8
Dependent Claim
30 words
The method of claim 1 where the hard mask comprises a material selected from the group of materials consisting of silicon dioxide, silicon nitride, titanium nitride, molybdenum, and titanium tungsten.
Claim 9
Independent Claim
148 words
A method of making plural thin film resistors in a semiconductor device wherein the resistors have clean surfaces for minimal contact resistance with electrical interconnects in contact therewith, the method comprising the steps of: (a) providing a thin film of resistor material on a surface of the semiconductor device and depositing a TiW mask on the film in a deposition chamber without breaking a vacuum in the deposition chamber; (b) delineating the TiW mask to a pattern corresponding to multiple resistors; (c) etching the delineated TiW mask with hydrogen peroxide to expose the film therebeneath; (d) wet etching the exposed film with a second etchant to leave multiple thin film resistors beneath the delineated TiW mask; (e) removing the remaining TiW mask; and (f) applying electrical interconnects to each of the resistors, whereby the plural resistors are free of contamination that may affect contact resistance with the interconnect.
Claim 10
Independent Claim
148 words
A method of making plural thin film resistors in a semiconductor device wherein the resistors have clean surfaces for minimal contact resistance with electrical interconnects in contact therewith, the method comprising the steps of: (a) providing a thin film of resistor material on a surface of the semiconductor device and depositing a TiW mask on the film in a deposition chamber without breaking a vacuum in the deposition chamber; (b) delineating the TiW mask to a pattern corresponding to multiple resistors; (c) etching the delineated TiW mask with hydrogen peroxide to expose the film therebeneath; (d) wet etching the exposed film with a second etchant to leave multiple thin film resistors beneath the delineated TiW mask; (e) removing the remaining TiW mask; and (f) applying electrical interconnects to each of the resistors, whereby the plural resistors are free of contamination that may affect contact resistance with the interconnect.
Claim 11
Dependent Claim
27 words
The method of claim 8 wherein the resistor material comprises NiCr and the second etchant comprises sulfuric acid that is at a temperature greater than 125° C.
Claim 12
Dependent Claim
26 words
The method of claim 8 wherein the resistor material comprises CrSi and the second etchant comprises a mixture of phosphoric acid, nitric acid and hydrofluoric acid.
Claim 13
Independent Claim
66 words
A method of producing a thin film resistor comprising the steps of masking a portion of a NiCr film with a hard mask that is immune to the etching effects of sulfuric acid heated to greater than 125° C., etching the hard mask with hydrogen peroxide that does not affect the film, and etching the film with sulfuric acid at a temperature greater than 125° C.
Claim 14
Independent Claim
66 words
A method of producing a thin film resistor comprising the steps of masking a portion of a NiCr film with a hard mask that is immune to the etching effects of sulfuric acid heated to greater than 125° C., etching the hard mask with hydrogen peroxide that does not affect the film, and etching the film with sulfuric acid at a temperature greater than 125° C.
Claim 15
Independent Claim
73 words
A method of producing a thin film resistor comprising the steps of masking a portion of a CrSi film with a hard mask that is immune to the etching effects of an etchant comprised of a mixture of phosphoric acid, nitric acid and hydrofluoric acid, etching the hard mask with hydrogen peroxide that does not affect the film, and etching the film with a mixture of phosphoric acid, nitric acid and hydrofluoric acid.
Claim 16
Independent Claim
73 words
A method of producing a thin film resistor comprising the steps of masking a portion of a CrSi film with a hard mask that is immune to the etching effects of an etchant comprised of a mixture of phosphoric acid, nitric acid and hydrofluoric acid, etching the hard mask with hydrogen peroxide that does not affect the film, and etching the film with a mixture of phosphoric acid, nitric acid and hydrofluoric acid.
Claim 17
Independent Claim
125 words
A method of etching a thin film resistor in a semiconductor device comprising the steps of: (a) depositing a thin film resistor comprising NiCr on a substrate and depositing a non-photoresist hard mask comprising one of TiW and molybdenum on an exposed surface of the thin film resistor; (b) etching a delineated portion of the hard mask with a hydrogen peroxide etchant that does not affect the thin film resistor to expose the resistor therebeneath; and (c) etching the exposed thin film resistor material with a second etchant that does not affect the hard mask; (d) etching the remaining hard mask with the hydrogen peroxide etchant to thereby expose the thin film resistor therebeneath; and (e) depositing electrical interconnects on the exposed thin film resistor.
Claim 18
Independent Claim
125 words
A method of etching a thin film resistor in a semiconductor device comprising the steps of: (a) depositing a thin film resistor comprising NiCr on a substrate and depositing a non-photoresist hard mask comprising one of TiW and molybdenum on an exposed surface of the thin film resistor; (b) etching a delineated portion of the hard mask with a hydrogen peroxide etchant that does not affect the thin film resistor to expose the resistor therebeneath; and (c) etching the exposed thin film resistor material with a second etchant that does not affect the hard mask; (d) etching the remaining hard mask with the hydrogen peroxide etchant to thereby expose the thin film resistor therebeneath; and (e) depositing electrical interconnects on the exposed thin film resistor.
Claim 19
Dependent Claim
19 words
The method of claim 13 wherein the second etchant is sulfuric acid at a temperature greater than 125° C.
Claim 20
Dependent Claim
35 words
The method of claim 13 wherein the step of depositing the thin film resistor and depositing the hard mask thereon are carried out in a deposition chamber without breaking a vacuum in the deposition chamber.
Claim 21
Independent Claim
122 words
A method of etching a thin film resistor in a semiconductor device comprising the steps of: (a) depositing a thin film resistor material on a substrate and depositing a non-photoresist hard mask on an exposed surface of the thin film resistor material in a deposition chamber without breaking a vacuum in the deposition chamber; (b) etching a delineated portion of the hard mask with a first etchant that does not affect the thin film resistor material to expose the material therebeneath; and (c) wet etching the exposed thin film resistor material with a second etchant that does not affect the hard mask; and (d) etching the remaining hard mask with the first etchant to thereby expose the thin film resistor material therebeneath.
Claim 22
Independent Claim
122 words
A method of etching a thin film resistor in a semiconductor device comprising the steps of: (a) depositing a thin film resistor material on a substrate and depositing a non-photoresist hard mask on an exposed surface of the thin film resistor material in a deposition chamber without breaking a vacuum in the deposition chamber; (b) etching a delineated portion of the hard mask with a first etchant that does not affect the thin film resistor material to expose the material therebeneath; and (c) wet etching the exposed thin film resistor material with a second etchant that does not affect the hard mask; and (d) etching the remaining hard mask with the first etchant to thereby expose the thin film resistor material therebeneath.
Claim 23
Dependent Claim
31 words
The method of claim 16 where the thin film resistor material comprises NiCr and wherein the hard mask comprises one of TiW and molybdenum and the first etchant comprises hydrogen peroxide.
Claim 24
Dependent Claim
19 words
The method of claim 17 wherein the second etchant is sulfuric acid at a temperature greater than 125° C.
Claim 25
Dependent Claim
31 words
The method of claim 16 where the thin film resistor material comprises CrSi and wherein the hard mask comprises one of TiW and molybdenum and the first etchant comprises hydrogen peroxide.
Claim 26
Dependent Claim
20 words
The method of claim 19 wherein the second etchant is a mixture of phosphoric acid, nitric acid and hydrofluoric acid.
Claim 27
Dependent Claim
20 words
The method of claim 16 further comprising the step of depositing electrical interconnects on the exposed thin film resistor material.
Claim 28
Dependent Claim
30 words
The method of claim 16 where the hard mask comprises a material selected from the group of materials consisting of silicon dioxide, silicon nitride, titanium nitride, molybdenum, and titanium tungsten.
Claim 29
Dependent Claim
28 words
The method of claim 11 further comprising the step of etching the remaining portion of the hard mask with hydrogen peroxide to thereby expose the NiCr film therebeneath.
Claim 30
Dependent Claim
18 words
The method of claim 23 further comprising the step of depositing electrical interconnects on the exposed NiCr film.
Claim 31
Dependent Claim
36 words
The method of claim 11 further comprising the step of etching the remaining portion of the hard mask except the portions of the hard mask overlying selected portions of the NiCr film for contacting electrical interconnects.
Claim 32
Dependent Claim
19 words
The method of claim 25 further comprising the step of depositing electrical interconnects on the remaining hard mask portions.
Claim 33
Dependent Claim
28 words
The method of claim 12 further comprising the step of etching the remaining portion of the hard mask with hydrogen peroxide to thereby expose the CrSi film therebeneath.
Claim 34
Dependent Claim
18 words
The method of claim 27 further comprising the step of depositing electrical interconnects on the exposed CrSi film.
Claim 35
Dependent Claim
36 words
The method of claim 12 further comprising the step of etching the remaining portion of the hard mask except the portions of the hard mask overlying selected portions of the CrSi film for contacting electrical interconnects.
Claim 36
Dependent Claim
19 words
The method of claim 29 further comprising the step of depositing electrical interconnects on the remaining hard mask portions.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-08-20 | 2000-02-19 | 2000-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-20 | 2004-02-19 | 2004-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-08-20 | 2008-02-19 | 2008-08-20 | $7700.00 | Window Closed / Lapsed |