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TBGA Substrate With Improved Wire Bondability

IP.com Disclosure Number: IPCOM000236756D
Publication Date: 2014-May-14
Document File: 3 page(s) / 213K

Publishing Venue

The IP.com Prior Art Database

Abstract

This paper presents a method to improve the wire bondability and reliability on existing TBGA substrate design, which has high Non-Stick On Leads (NSOL)/short tails stoppages due to the soft elastomer adhesive material used between the copper heat spreader and the tape substrate. Other issues such as the bouncing effect due to the soft elastomer materials also make wire looping stability challenging. High out gassing issue caused by the elastomer adhesive layer is also causing contamination on the bonding pads, leads or even on the wire bonder, which is critical to copper wire bond reliability.

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TITLE

TBGA Substrate With Improved Wire Bondability

ABSTRACT

This paper presents a method to improve the wire bondability and reliability on existing TBGA substrate design, which has high Non-Stick On Leads (NSOL)/short tails stoppages due to the soft elastomer adhesive material used between the copper heat spreader and the tape substrate. Other issues such as the bouncing effect due to the soft elastomer materials also make wire looping stability challenging.  High out gassing issue caused by the elastomer adhesive layer is also causing contamination on the bonding pads, leads or even on the wire bonder, which is critical to copper wire bond reliability.

CONTENT

We propose replacing the elastomer tape between the metal heat spreader and the interposer/substrate with a high thermal conductivity molding compound. This solid layer will provide a more rigid base, which will improve the wire bondability, wire bond yield with minimum bouncing effect, and reduce the out gassing contamination issue, which is critical for Copper wire bonding process.

Important Components:

Ø    Existing TBGA design with polymeric/elastomer adhesive layer between the Copper Heat Spreader and the Substrate/Metal Layer Tape:

 

Proposed Design Important Components:

Ø Substitute the elastomer/polymer adhesive layer with a layer of molding compound: