US5256247A
Expired / Lapsed
US
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Liquid etchant composition for thin film resistor element
Assignee: Hitachi Ltd
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Filing: 1991-11-21
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Granted: 1993-10-26
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Expires: 2011-11-21
Abstract
Abstract A resistor material having at least chromium, silicon and oxygen, Cr.SiO2, contained in electronic integrated circuits, particularly in the case of an aluminum layer being on the material, is etched with a liquid etchant composition containing 1.92 to 2.64 mol/l of hydrochloric acid, 0.26 to 0.77 mol/l of phosphoric acid, 5 to 10 mol/l hydrofluoric acid and 3.2 to 5.4 mol/l of ammonium fluoride.
Inventors
- 👤 Takayoshi Watanabe
- 👤 Takashi Inoue
- 👤 Hitoshi Oka
- 👤 Minoru Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:48
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B41/45; C04B41/52; C04B41/53; C04B41/5338; C04B41/5353; C04B41/80; C04B41/81; C04B41/89; C04B41/91; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; C23F1/26; H; H01; H01C; H01C17/00; C04B2111/00; C04B2111/00474; C04B2111/00844
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
117 words
A method of forming a thin film resistor element comprising a laminate comprising a chromium, silicon and oxygen-containing film as a resistor and an aluminum film as a conductor on a substrate, which comprises preparing the chromium, silicon and oxygen-containing film on the substrate and subsequently the aluminum film on the chromium, silicon and oxygen-containing film to form a laminate, providing a photoresist pattern on the aluminum film, etching the aluminum film and then etching the chromium, silicon and oxygen-containing film with an aqueous etchant composition consisting of 1.92 to 2.64 mol/l of hydrochloric acid, 0.26 to 0.77 mol/l of phosphoric acid, 5 to 10 mol/l of hydrofluoric acid and 3.2 to 5.4 mol/l of ammonium fluoride.
Claim 2
Independent Claim
117 words
A method of forming a thin film resistor element comprising a laminate comprising a chromium, silicon and oxygen-containing film as a resistor and an aluminum film as a conductor on a substrate, which comprises preparing the chromium, silicon and oxygen-containing film on the substrate and subsequently the aluminum film on the chromium, silicon and oxygen-containing film to form a laminate, providing a photoresist pattern on the aluminum film, etching the aluminum film and then etching the chromium, silicon and oxygen-containing film with an aqueous etchant composition consisting of 1.92 to 2.64 mol/l of hydrochloric acid, 0.26 to 0.77 mol/l of phosphoric acid, 5 to 10 mol/l of hydrofluoric acid and 3.2 to 5.4 mol/l of ammonium fluoride.
Claim 3
Dependent Claim
17 words
The method according to claim 1, wherein the chromium, silicon and oxygen-containing film is prepared by sputtering.
Claim 4
Dependent Claim
23 words
The method according to claim 1, wherein there is present a polyimide coating between the substrate and the chromium, silicon and oxygen-containing film.
Claim 5
Independent Claim
140 words
A method of etching a thin film of a resistor material comprising at least chromium, silicon and oxygen, said film being formed on a substrate, and said thin film having an aluminum film applied thereto, which comprises etching the aluminum film to expose a portion of the thin film of the resistor material, then etching the exposed thin film of resistor material with a liquid etchant composition consisting of water, hydrochloric acid, phosphoric acid, hydrofluoric acid and ammonium fluoride; the concentration of the hydrochloric acid being in the range of 1.92 to 2.64 mol/l, the concentration of the phosphoric acid being in the range of 0.26 to 0.77 mol/l, the concentration of the hydrofluoric acid being in the range of 5 to 10 mol/l and the concentration of the ammonium fluoride being in the range of 3.2 to 5.4 mol/l.
Claim 6
Independent Claim
140 words
A method of etching a thin film of a resistor material comprising at least chromium, silicon and oxygen, said film being formed on a substrate, and said thin film having an aluminum film applied thereto, which comprises etching the aluminum film to expose a portion of the thin film of the resistor material, then etching the exposed thin film of resistor material with a liquid etchant composition consisting of water, hydrochloric acid, phosphoric acid, hydrofluoric acid and ammonium fluoride; the concentration of the hydrochloric acid being in the range of 1.92 to 2.64 mol/l, the concentration of the phosphoric acid being in the range of 0.26 to 0.77 mol/l, the concentration of the hydrofluoric acid being in the range of 5 to 10 mol/l and the concentration of the ammonium fluoride being in the range of 3.2 to 5.4 mol/l.
Claim 7
Dependent Claim
30 words
The method according to claim 4, wherein the thin film of a resistor material comprises a chromium-silicon dioxide sputtered thin film and the substrate comprises a ceramic material or glass.
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