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Electroless plating of aluminum bond pads on semiconductor devices that were originally bonded with copper wires to allow for repackaging to facilitate failure analysis

IP.com Disclosure Number: IPCOM000237915D
Publication Date: 2014-Jul-21
Document File: 4 page(s) / 90K

Publishing Venue

The IP.com Prior Art Database

Abstract

In failure analysis, there are increasingly more cases where the semiconductor die needs to be repackaged into a secondary package for electrical fault isolation. When a product is originally bonded using copper wire bonds, the repackaging process removes all traces of the wire. The remaining aluminum on the bond pads may be very thin and may not allow for rebonding for failure analysis. In order to work around this, the remaining bond pads can be re-plated to allow for rebonding. For example, they may be electrolessly plated with nickel, palladium, and gold. The plated material provides a bondable surface for the re-packaging process.

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Electroless plating of aluminum bond pads on semiconductor devices that were originally bonded with copper wires to allow for repackaging to facilitate failure analysis.

Abstract

In failure analysis, there are increasingly more cases where the semiconductor die needs to be repackaged into a secondary package for electrical fault isolation.  When a product is originally bonded using copper wire bonds, the repackaging process removes all traces of the wire.  The remaining aluminum on the bond pads may be very thin and may not allow for rebonding for failure analysis.  In order to work around this, the remaining bond pads can be re-plated to allow for rebonding.  For example, they may be electrolessly plated with nickel, palladium, and gold.  The plated material provides a bondable surface for the re-packaging process.

Body

In failure analysis, electrical defect localization can be performed from the frontside or the backside of the die.  Increasingly, there are package configurations and process technology limitations that require the semiconductor die to be extracted and repackaged into a secondary package for electrical fault localization.  In repackaging on devices with copper wire bonds the wire bonds on the die are etched off during die extraction leaving a “dimple” area on the aluminum bond pad.  The thickness of aluminum at this dimple may be very thin (0~0.5µm versus 1.2µm on an unbonded pad).  As such, it is not possible to perform gold wire bonding and repackaging of the die as the remaining thickness of aluminum is too thin for the intermetallic to form resulting in non-stick bonds. ...