EP0263221A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of forming solder bumps on metal contact pads of a substrate
Assignee: International Business Machines Corp
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Filing: 1986-10-08
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Granted: —
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Expires: 2006-10-08
Abstract
Abstract Disclosed is a method of forming solder bumps (21) on an electrically insulating substrate (10) provided with a plurality of minute metal contact pads (15) according to a grid pattern at the center or the said substrate characterized in the steps of first applying a droplet of flux to any contact pad where desired, applying a solder preform to the said previously fluxed pad to which it will adhere because the adhesive property of the flux, heating to cause a solder reflow of the solder preform and cooling below the melting point of the solder whereby the molten solder solidifies to form the said solder bumps.
Inventors
- 👤 Pierre Beaudouin
- 👤 Michel Joseph Grandguillot
- 👤 Alexis Bitaillou
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 21:56
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/3465; H05K3/3478; H10; H10W; H10W70/00; H10W70/099; H05K1/00; H05K1/02; H05K1/03; H05K1/0306; H05K2201/00; H05K2201/10; H05K2201/10613; H05K2201/10621; H05K2201/10734; H05K2203/00; H05K2203/04; H05K2203/041; H05K2203/043; H05K2203/0485; H05K3/10; H05K3/12; H05K3/1216; H05K3/1225; H05K3/3489
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
108 words
A method of forming solder bumps (21) on an electrically insulating substrate (10) provided with a plurality of minute metal contact pads (15) according to a grid pattern of said substrate (10) characterized in the steps of first applying a droplet of flux (19) to any contact pad (15) where desired, applying a solder preform (20) to the said previously fluxed pad to which it will adhere because of the adhesive property of the flux, heating to cause a solder reflow of the solder preform a nd cooling to below the melting point of the solder whereby the molten solder solidifies to form the said solder bumps (21).
Claim 2
Independent Claim
108 words
A method of forming solder bumps (21) on an electrically insulating substrate (10) provided with a plurality of minute metal contact pads (15) according to a grid pattern of said substrate (10) characterized in the steps of first applying a droplet of flux (19) to any contact pad (15) where desired, applying a solder preform (20) to the said previously fluxed pad to which it will adhere because of the adhesive property of the flux, heating to cause a solder reflow of the solder preform a nd cooling to below the melting point of the solder whereby the molten solder solidifies to form the said solder bumps (21).
Claim 3
Dependent Claim
15 words
The method of claim 1 including further the step of cleaning to eliminate flux residuals.
Claim 4
Dependent Claim
29 words
The method of claim 1 or 2 wherein the step of applying a droplet of flux consists in forcing the flux through a mask (16) having pipe-shaped holes (17).
Claim 5
Dependent Claim
16 words
The method of claim 1, 2 or wherein the said solder preform is a solder ball.
Claim 6
Dependent Claim
27 words
The method of claim 4 wherein the solder ball has a diameter of about .7 mm and comprises 90% by weight lead and 10% by weight tin.
Claim 7
Independent Claim
26 words
The method of any above claim wherein the said metal contact pads forming the said grid pattern occupy the whole surface of the said insulating substrate.
Claim 8
Independent Claim
30 words
The method of any above claim wherein the said insulating substrate (10) consists of a MLC substrate and the said contact pads are circular and formed by a nickel/gold plating.
References Cited (Backward Citations)
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