Bond Pad Gap for Aluminum Splash Containment
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Solution Overview
Problem
During wire bonding in semiconductor devices, the deformation of aluminum bond pads leads to conductive splashes that can cause passivation cracking, resulting in reliability failures.
Innovation Solution
A gap is formed in the bond pad and passivation layer, positioned and sized to contain the splash, which is achieved by patterning the passivation layer to create openings between the bond pads, thereby accommodating the splash and preventing unintended contact with other conductive structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is performed on aluminum bond pads, then electrical connections are established, but aluminum splash causes passivation cracking
Solution Approach 1:
The passivation layer is segmented by creating gaps that divide it into separate regions. These gaps are strategically positioned to intercept and contain aluminum splash before it can propagate and crack the passivation layer, thereby resolving the contradiction between maintaining passivation integrity and allowing wire bonding operations.
Solution Approach 2:
The gap acts as an intermediary element between the bond pad and the passivation layer. It provides a controlled space that captures the aluminum splash, preventing direct contact between the splash and the passivation layer, thus eliminating the harmful effect while preserving the electrical connection function.
2Object-affected harmful factors
If passivation layer is continuous, then device protection is maintained, but splash causes cracking
Solution Approach 1:
The continuous passivation layer is intentionally segmented into discrete regions separated by gaps. This segmentation allows the passivation to maintain its protective function in covered areas while the gaps provide controlled spaces to contain aluminum splash, preventing crack propagation and preserving overall passivation integrity.
3Area of stationary object
If bond pads are placed close together, then device area is reduced, but splash may contact adjacent conductive structures
Solution Approach 1:
The gap serves as an intermediary barrier between adjacent bond pads and their associated splashes. By positioning gaps between conductive structures, the design enables closer placement of bond pads to reduce device area while the gaps prevent unintended contact between aluminum splash and adjacent conductive elements.
Solution Approach 2:
The passivation layer is modified locally by creating gaps only in specific positions where splash containment is needed, rather than making the entire passivation layer discontinuous. This localized modification allows close spacing of bond pads while maintaining protection in other areas.
Data Source
AI summary
A semiconductor device comprises an integrated circuit including a wire bond pad and a passivation material, and a first gap between a first selected portion of the wire bond pad and the passivation material. The first gap is positioned to contain at least a first portion of a splash of the wire bond pad formed during a wire bond process.