EP0055378A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A method of brazing adjoining surfaces of elements
Assignee: International Business Machines Corp
•
Filing: 1981-10-29
•
Granted: —
•
Expires: 2001-10-29
Abstract
Abstract Brazing of metallic elements to an electronic circuit board carrying a plurality of chips requires brazing materials which remain strong at high temperatures used to remove and replace the chips attached by solder balls to the board. According to the present invention flanges and pins (19) are brazed to the board (10) with a gold tin brazing solder (15) which is modified during brazing by addition of a Group IB metal (13) to promote formation of the higher melting point β phase of the solder and a Group VIII metal (14) to drawtin out of the melt by gettering. The melting temperature of the brazing solder is raised substantially during brazing to a value above the melting temperature of the solder balls attached to the chips.
Inventors
- 👤 Norman George Ainslie
- 👤 James Edward Krzanowski
- 👤 Paul Harry Palmateer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 08:06
CPC Classifications
B; B23; B23K; B23K35/00; B23K35/22; B23K35/24; B23K35/30; B23K35/3013; B23K35/001; H; H10; H10W; H10W70/00; H10W70/099; H10W90/00; H10W90/701; H10W90/721; H10W90/724
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
81 words
A method of brazing adjoining surfaces of elements (10, 19) by means of a gold tin brazing solder (15), characterised in that the method comprises providing a Group IB metal (13) and a Group VIII metal (14) in combination with said brazing solder (15), to come into contact with said elements (10, 19) during brazing, whereby the melting temperature of said brazing solder (15) is raised substantially during brazing to a value above the initial melting temperature of the solder (15).
Claim 2
Independent Claim
81 words
A method of brazing adjoining surfaces of elements (10, 19) by means of a gold tin brazing solder (15), characterised in that the method comprises providing a Group IB metal (13) and a Group VIII metal (14) in combination with said brazing solder (15), to come into contact with said elements (10, 19) during brazing, whereby the melting temperature of said brazing solder (15) is raised substantially during brazing to a value above the initial melting temperature of the solder (15).
Claim 3
Dependent Claim
66 words
A method as claimed in claim 1, in which one of said elements is an electronic circuit board carrying a plurality of chips attached thereto by means of solder balls and the other element is in an electrical connection pin or other metallic component, the melting temperature of said brazing solder being raised substantially during brazing to a value above the melting temperature of'the solder balls.
Claim 4
Dependent Claim
29 words
A method as claimed in claim 2, in which said Group IB and Group VIII metals are coated on the surface of said board prior to the brazing operation.
Claim 5
Dependent Claim
32 words
A method as claimed in claim 2 or 3, in which said Group IB and Group VIII metals are coated on the surface of said metallic component prior to the brazing operation.
Claim 6
Dependent Claim
29 words
A method as claimed in claim 2 or 3, in which said Group IB and Group VIII metals are derived from the composition of said metallic elements during brazing.
Claim 7
Dependent Claim
31 words
A method as claimed in claim 5, in which said metallic component is composed of a core of said Group IB metal coated with said Group VIII metal prior to brazing.
Claim 8
Dependent Claim
38 words
A method as claimed in claim 2, in which a flat preform of said Group IB metal and said Group VIII metal is located within a braze fillet between said board and said metallic component prior to brazing.
Claim 9
Dependent Claim
22 words
A method as claimed in claim 7, in which said preform is an alloy of said Group IB and Group VIII metals.
Claim 10
Dependent Claim
25 words
A method as claimed in claim 7, in which said preform comprises a slab of said Group IB metal coated with said Group VIII metal.
Claim 11
Independent Claim
42 words
A method as claimed in any one of the preceding claims, in which said Group IB metal is selected from Cu, Ag and Au and said Group VIII metal is selected from Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, and Pt.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.