Claims
- 1. A method of producing a metal film resistor having a fuse function, comprising the steps of:
- imparting conductivity to a surface of an electrically insulating substrate by:
- sequentially performing an etching treatment,
- performing an activating treatment,
- performing an electroless plating treatment to the electrically insulating substrate, and
- forming a film of a nickel-phosphorous alloy on the electrically insulating substrate by an electrolytic plating treatment, which is conducted so that said film has a thickness in edge parts which is greater than that of other thinner parts of the film to provide a fusing function in the other thinner parts
- wherein the film of a nickel-phosphorous alloy is formed on the surface of the electrically insulating substrate by dipping the electrically insulating substrate, which has been rendered conductive, into a plating solution having a pH 0.5 to 5.5 and a temperature of 20.degree. to 70.degree. C., said solution containing 0.5 to 4.0 mol/l of nickel, 0.1 to 1.5 mol/l of phosphoric acid, phosphorous acid, or hypophosphorous acid, and 0.2 to 1.5 mol/l of boric acid;
- performing the electrolytic plating treatment at a current density of 0.1 to 10 A/dm.sup.2 ; and then
- performing a heat ageing treatment on the film of a nickel-phosphorous alloy and the electrically insulating substrate.
- 2. A method in accordance with claim 1 wherein said insulating substrate is a ceramic substrate.
- 3. A method of producing a metal film resistor having a fuse function, comprising the steps of:
- imparting conductivity to a surface of an electrically insulating substrate by:
- sequentially performing an etching treatment,
- an activating treatment;
- an electroless plating treatment to the electrically insulating substrate; and
- forming a film of a nickel-iron-phosphorous alloy on the electrically insulating substrate by an electrolytic plating treatment which is conducted so that said film has a thickness in edge parts which is greater than that of other thinner parts of the film to provide a fusing function in the other thinner parts.
- 4. A method as claimed in claim 3 wherein:
- the film of a nickel-iron-phosphorous alloy is formed on the surface of the electrically insulating substrate by:
- dipping the electrically insulating substrate, which has been rendered conductive, into a plating solution having a pH 0.5 to 5.5 and a temperature of 20.degree. to 70.degree. C., said solution containing 0.5 to 4.0 mol/l of nickel, 0.001 to 1.0 mol/l of iron, 0.1 to 1.5 mol/l of phosphoric acid, phosphorous acid or hypophosphorous acid, and 0.2 to 1.5 mol/l of boric acid;
- performing the electrolytic plating treatment at a current density of 0.5 to 10 A/dm.sup.2 ; and then
- performing a heat ageing treatment on the film of a nickel-iron-phosphorous alloy and the electrically insulating substrate.
- 5. A method in accordance with claim 3 wherein said insulating substrate is a ceramic substrate.
Priority Claims (1)
Number |
Date |
Country |
Kind |
5-113320 |
May 1993 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 08/360,814, filed as PCT/JP94/00739 May 2, 1994, now abandoned.
US Referenced Citations (15)
Foreign Referenced Citations (4)
Number |
Date |
Country |
3504186 |
Aug 1985 |
DEX |
52-96397 |
Aug 1977 |
JPX |
67-20687 |
Apr 1982 |
JPX |
9514116 |
May 1995 |
WOX |
Continuations (1)
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Number |
Date |
Country |
Parent |
360814 |
Dec 1994 |
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