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Method for forming a metal film on the surface of a substrate metal

Assignee: Harima Chemicals Inc
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Filing: 1989-03-13
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Granted: 1991-06-04
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Expires: 2009-03-13
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Abstract

Abstract A method for forming a metal film on the surface of a substrate metal, which comprises soaking a substrate metal or a non-metal support carrying the substrate metal thereon in a solution of a metal salt in a high boiling point solvent under heating conditions, characterized in that the metal salt is a salt of the metal to be formed on the surface of the substrate metal with an acidic substance selected from an organic carboxylic acid, a rosin and a rosin derivative. The metal is precipitated from the solution exclusively on the surface of the substrate metal without forming any solid metal particle in the solution or on the substrate metal. Thus, the method is applicable to the formation of a soldering alloy as a film on the surface of a substrate metal without leaving thereon any free metal particle which may cause short circuits in electronic circuits. The method can thus be applied advantageously to the manufacture of electronic elements having a metal film thereon and high density printed circuits, and thus is also useful in the field of electronic industry.

Inventors

  • 👤 Masanao Kono
  • 👤 Yoshihiro Hasegawa
  • 👤 Yasutaka Nishi
  • 👤 Hisao Irie
  • 👤 Tatsuji Mizuta
  • 👤 Shinsuke Ohara

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 15:28
CPC Classifications
B; B23; B23K; B23K1/00; C; C23; C23C; C23C18/00; C23C18/02; C23C18/08; H; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/3465; H05K3/3473; H05K2203/00; H05K2203/07; H05K2203/0756; H05K2203/0776; H05K2203/0779; H05K2203/0783; H05K2203/11; H05K2203/1105; H05K2203/12; H05K2203/125; H05K3/10; H05K3/105; H05K3/22; H05K3/24; H05K3/244; H05K3/3494

Claims Analysis

Total Claims: 15
Claim 1
Independent Claim 157 words
A method for forming a soldering alloy film on the surface of a circuit panel metal substrate for electronic parts, which comprises soaking the metal substrate or a non-metal support having the metal substrate disposed thereon in a solution of a soldering alloy salt in a high boiling point solvent, at a temperature of from about 230° to 280° C., characterized in that the soldering alloy salt is a salt of a soldering alloy, which is the soldering alloy to be formed on the surface of the metal substrate, and an acidic substance selected from the group consisting of an organic carboxylic acid having at least 4 carbon atoms, an acidic substance of natural origin containing abietic acid and d-pimaric acid and that which has been modified to contain 2 or 3 carboxyl groups, wherein the metal substrate is larger in ionization tendency than the soldering alloy to be formed on the surface of the metal substrate.
Claim 2
Independent Claim 157 words
A method for forming a soldering alloy film on the surface of a circuit panel metal substrate for electronic parts, which comprises soaking the metal substrate or a non-metal support having the metal substrate disposed thereon in a solution of a soldering alloy salt in a high boiling point solvent, at a temperature of from about 230° to 280° C., characterized in that the soldering alloy salt is a salt of a soldering alloy, which is the soldering alloy to be formed on the surface of the metal substrate, and an acidic substance selected from the group consisting of an organic carboxylic acid having at least 4 carbon atoms, an acidic substance of natural origin containing abietic acid and d-pimaric acid and that which has been modified to contain 2 or 3 carboxyl groups, wherein the metal substrate is larger in ionization tendency than the soldering alloy to be formed on the surface of the metal substrate.
Claim 3
Dependent Claim 48 words
The method according to claim 1, wherein the soldering alloy to be formed on the surface of the metal substrate is comprised of at least two of the metals selected from the group consisting of zinc, cadmium, chromium, iron, nickel, cobalt, tin, lead, bismuth, copper, silver and gold.
Claim 4
Dependent Claim 27 words
The method according to claim 1, wherein the soldering alloy to be formed on the surface of the metal substrate is a mixture of tin and lead.
Claim 5
Dependent Claim 26 words
The method according to claim 1 wherein the metal of the metal substrate is selected from the group consisting of zinc, aluminum, iron, nickel and copper.
Claim 6
Dependent Claim 15 words
The method according to claim 14, wherein the metal of the metal substrate is copper.
Claim 7
Dependent Claim 17 words
The method according to claim 1, wherein the non-metal support is a glass or a resinous base.
Claim 8
Dependent Claim 18 words
The method according to claim 14, wherein the solvent is squalene and the soaking temperature is 250° C.
Claim 9
Dependent Claim 17 words
The method according to claim 1 wherein the soaking time is from several seconds to several minutes.
Claim 10
Dependent Claim 26 words
The method according to claim 1, wherein the organic carboxylic acid having at least 4 carbon atoms is an aromatic mono-carboxylic acid or a di-carboxylic acid.
Claim 11
Dependent Claim 21 words
The method according to claim 1, wherein the organic carboxylic acid having at least 4 carbon atoms is a fatty acid.
Claim 12
Dependent Claim 18 words
The method according to claim 1, wherein the acidic substance of natural origin are rosins and derivatives thereof.
Claim 13
Dependent Claim 44 words
The method according to claim 11, wherein the rosin derivative is selected from the group consisting of a disproportioned rosin, a hydrogenated rosin, a gum rosin, a tall oil rosin, a wood rosin, a maleic acid-adduct of rosin and a fumaric acid-adduct of rosin.
Claim 14
Dependent Claim 20 words
The method according to claim 1, wherein the soldering alloy content in the solution is at least 0.1% by weight.
Claim 15
Dependent Claim 26 words
The method according to claim 1, wherein the high boiling point solvent is selected from the group consisting of squalene and high boiling point mineral spirits.

References Cited (Backward Citations)

US2813805A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-06-03 1994-12-03 1995-06-04 $2000.00 Window Closed / Lapsed
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