Direct etch for thin film resistor using a hard mask
First Claim
1. 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.
5 Assignments
0 Petitions
Accused Products
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.
57 Citations
30 Claims
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1. A method of etching a thin film resistor in a semiconductor device comprising the steps of:
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(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. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. 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:
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(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. - View Dependent Claims (9, 10)
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11. 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. - View Dependent Claims (23, 24, 25, 26)
- 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°
- 12. 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.
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13. A method of etching a thin film resistor in a semiconductor device comprising the steps of:
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(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. - View Dependent Claims (14, 15)
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16. A method of etching a thin film resistor in a semiconductor device comprising the steps of:
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(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. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification