EP0089604A1
Expired / Lapsed
EP
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Method for selectively coating metallurgical patterns on dielectric substrates
Assignee: International Business Machines Corp
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Filing: 1983-03-15
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Granted: —
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Expires: 2003-03-15
Abstract
Abstract The coating, like coating,(14), is produced by selectively depositing metals, like metals (16, 17), over an existing metallurgical pattern (3) supported on or recessed in a dielectric substrate (1). The coating is formed by the following steps. Sequentially blanket coating said substrate (1) and said pattern (3) with metals, like metals (16,17), being tuned to another in such a way that on heating a liquid metal or alloy layer, like alloy layer (18A), is formed adjacent the surface of substrate (1) and pattern (3) where said liquid layer wets said pattern (3) but not said substrate (1); heating the then present structure to a temperature where said liquid metal or said alloy layer, like layer (18A), is formed; cooling said structure; and removing said metals, like metals (16,17), from the surface of said substrate (1) not covered by said pattern (3). The method is applicable in selectively depositing a brazeable and solderable, protective metal coating on refractive metal conductive patterns on ceramic substrate carriers employed for mounting semiconductor devices.
Inventors
- 👤 Ananda Hosakere Kumar
- 👤 Kris Venkatraman Srikrishnan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 09:51
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/80; C04B41/81; C04B41/85; C04B41/88; B; B23; B23K; B23K35/00; B23K35/001; C04B41/009; C04B41/45; C04B41/50; C04B41/51; H; H05; H05K; H05K3/00; H05K3/22; H05K3/24; H05K3/245; H05K3/246; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10W20/057; H10W70/00; H10W70/01; H10W70/05; H05K1/00; H05K1/02; H05K1/03; H05K1/0306; H05K3/02; H05K3/04; H05K3/046; H05K3/048; H05K3/10; H05K3/14; H05K3/143; H05K3/244
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
107 words
Method for selectively depositing metal coatings over an existing metallurgical pattern supported on or recessed in a dielectric substrate, characterized by the following steps: A) sequentially blanket coating said substrate and said pattern with metals tuned to another in such a way that on heating a liquid metal or alloy layer is formed adjacent the substrate and pattern surface where said layer wets said pattern but not said substrate; B) heating the then present structure to a temperature where said liquid metal or alloy layer is formed; C) cooling said structure; and D) removing said metals from the surface of said substrate not covered by said pattern.
Claim 2
Dependent Claim
107 words
Method for selectively depositing metal coatings over an existing metallurgical pattern supported on or recessed in a dielectric substrate, characterized by the following steps: A) sequentially blanket coating said substrate and said pattern with metals tuned to another in such a way that on heating a liquid metal or alloy layer is formed adjacent the substrate and pattern surface where said layer wets said pattern but not said substrate; B) heating the then present structure to a temperature where said liquid metal or alloy layer is formed; C) cooling said structure; and D) removing said metals from the surface of said substrate not covered by said pattern.
Claim 3
Dependent Claim
15 words
Method according to claim 1, wherein said metal coatings consist of brazeable and solderable metals.
Claim 4
Dependent Claim
21 words
Method according to claim 1 or 2, wherein said dielectric substrate is comprised of a ceramic, like an alumina based ceramic.
Claim 5
Dependent Claim
21 words
Method according to any one of claims 1 to 3, wherein said metallurgical pattern is comprised of a refractory based metal.
Claim 6
Dependent Claim
18 words
Method according to claim 4, wherein the refractory metal is selected from the group of molybdenum and tungsten.
Claim 7
Dependent Claim
22 words
Method according to any one of claims 1 to 5, wherein said coatings are ultrasonically removed from said bare substrate surface areas.
Claim 8
Dependent Claim
136 words
Method according to any one of claims 1 to 6, wherein the following process steps are executed A) sequentially blanket coating said substrate (1), inclusive of said pattern (2, 3), with discrete levels of diverse metals having a differential in melting points (a) bondable to said pattern (b) non-wetting to the bare surface (7) of said substrate (1), with the metal having the lowest melting point disposed adjacent said substrate; B) heating the then present structure to a temperature above the melting point of the lower melting metal; C) cooling said structure to delaminate the metal coatings on the bare surfaces (7) of said substrate (1); and D) removing said delaminated coatings from the bare surface areas of said substrate (1) to retain a bonded cladding comprised of said metals on said metallurgical pattern (2, 3).
Claim 9
Dependent Claim
53 words
Method according to claim 7, wherein said diverse metals form alloy systems and show a behaviour according to Raoult's law or a positive deviation from it and wherein the temperature in said heating steps does not exceed the liquidus temperature of any resultant completely homogenized alloy corresponding to their amounts of metals deposited.
Claim 10
Dependent Claim
26 words
Method according to claim 7 or 8, wherein the substrate (1) adjacent metal is selected from the group of copper, nickel, nickel/palladium alloy and copper/palladium alloy.
Claim 11
Dependent Claim
138 words
Method according to claim 7, wherein the following process steps are executed A) depositing a blanket coating of a first metal layer (5) over said substrate (1), inclusive of said pattern (2, 3) with said first metal layer (5) having a melting point lower than that pattern and being adherent thereto; B) depositing a blanket coating of a second metal layer (6) over said first metal layer (5), with said second metal layer (6) having a melting point higher than that of said first metal layer (5); C) heating the then present structure to below the melting point of said second metal layer (6) and above said of said first metal layer (5) for selective melting thereof; and D) removing said first and second metal layers (5, 6) from the unpatterned surface areas (7) of said substrate (1).
Claim 12
Dependent Claim
23 words
Method according to claim 10, wherein said first metal layer (5) is selected from the group of copper, nickel and gold based metals.
Claim 13
Dependent Claim
19 words
Method according to claim 10 or 11, wherein said second metal layer (6) is comprised of a refractory metal.
Claim 14
Dependent Claim
22 words
Method according to claim 12, wherein the step of selective removal thereof from the cladding on said pattern (2, 3) is included.
Claim 15
Dependent Claim
152 words
Method according to any one of claims 1 to 6, wherein the following process steps are executed A) sequentially blanket coating said substrate (1) inclusive of said pattern with discrete levels of diverse alloyable metals (16, 17) showing a negative deviation from Raoult's law in their phase diagram with the alloy 'of said metals bondable to said pattern and non-wetting to the bare surfaces (12) of said substrate; B) heating the then present structure to a temperature below the melting point of said metals (16, 17) and above the lowest liquidus temperature in the phase diagram of the alloy system of said metals (16, 17), whereby a cladding of said metals (16, 17) is bonded to said pattern and form loosely adhered segments (14A) on said bare surfaces (12) of said substrate (1); C) cooling said structure; and D) removing said segments (14A) from said bare surfaces (12) of said substrate (1).
Claim 16
Dependent Claim
21 words
Method according to claim 14, wherein said metals are selected to form one of Pd/Ni, Au/Ni and Au/Cu binary alloy systems.
Claim 17
Dependent Claim
27 words
Method according to claims 14 or 15, wherein said metallurgical pattern comprises contact points on the surfaces of said substrate (1) for solder or brazing elements thereto.
Claim 18
Dependent Claim
18 words
Method according to any one of claims 14 to 16, wherein said substrate (1) is a multilayer ceramic.
References Cited (Backward Citations)
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