US 5,767,010 AGranted

Solder bump fabrication methods and structure including a titanium barrier layer

AssigneeMcnc

InventorsJoseph Daniel Mis, Gretchen Maerker Adema, Mark D. Kellam, W. Boyd Rogers

Life of this patent

Estimating the term…

Loading patent…

Abstract

A method for fabricating solder bumps on a microelectronic device having contact pads includes the steps of depositing a titanium barrier layer on the device, forming an under bump metallurgy layer on the titanium barrier layer, and forming one or more solder bumps on the under bump metallurgy layer. The solder bump or bumps define exposed portions of the under bump metallurgy layer which are removed, and then the exposed portion of the titanium barrier layer is removed. The titanium barrier layer protects the underlying microelectronic device from the etchants used to remove the under bump metallurgy layer. The titanium layer also prevents the under bump metallurgy layer from forming a residue on the underlying microelectronic device. Accordingly, the titanium barrier layer allows the under bump metallurgy layer to be quickly removed without leaving residual matter thereby reducing the possibility of electrical shorts between solder bumps.

Claims35

Dependent claims

A method for forming solder bumps on a microelectronic device having a substrate and a contact pad on said substrate, wherein said contact pad has an exposed surface portion, said method comprising the steps of:

forming a titanium barrier layer on said contact pad, wherein said barrier layer covers said exposed surface portion of said contact pad and extends over said substrate;
forming an under bump metallurgy layer on said barrier layer opposite said substrate, said under bump metallurgy layer comprising a chromium layer on said barrier layer, a phased layer of chromium and copper on said chromium layer opposite said barrier layer, and a copper layer on said phased layer opposite said chromium layer;
forming a solder bump on said under bump metallurgy layer opposite said exposed surface portion of said contact pad and opposite said titanium barrier layer thereby defining exposed and unexposed portions of said under bump metallurgy layer;
applying a chemical etchant to said exposed portions of said under bump metallurgy layer wherein said chemical etchant attacks said under bump metallurgy layer preferentially with respect to said solder bump and said titanium barrier layer thereby defining an exposed portion of said titanium barrier layer;
and
applying a titanium etchant to said exposed portion of said titanium barrier layer wherein said titanium etchant selectively attacks said titanium barrier layer preferentially with respect to said solder bump, said copper layer, said phased layer, and said chromium layer.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/744,122Filed 5 Nov 1996 · continuation
Priority: 2 Mar 1995
Granted: 16 Jun 1998
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

H10P 14/47
Using a liquid: electrolytic deposition, i.e. electroplating; Electroless plating
H10W 72/01204
Of bump connectors, dummy bumps or thermal bumps: using temporary auxiliary members, e.g. using sacrificial coatings or handle substrates
H10W 72/01235
In liquid form, e.g. spin coating, spray coating or immersion coating: by plating, e.g. electroless plating or electroplating
H10W 72/01255
Changing the shapes of bumps: by using masks