Seal Ring Bonding Via Structure for Passivation Void Mitigation
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Solution Overview
Problem
Void formation in the passivation layer around the metal pad structure of the seal ring structure in semiconductor die packages leads to delamination and film peeling, which can cause debonding between IC dies, reducing the reliability and failure of the semiconductor die package.
Innovation Solution
A recess is formed in the passivation layer to open up voids in the metal pad structure, which are then filled with a bonding via and bonding pad to enhance structural rigidity and prevent delamination, thereby increasing the reliability of the semiconductor die package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal pad structure is formed in the passivation layer, then electrical connectivity is achieved, but voids form around the metal pad structure causing delamination and film peeling
Solution Approach 1:
A recess is formed in the passivation layer at the metal pad structure location before depositing the bonding via and bonding pad materials. This preliminary action creates a cavity that prevents void formation during subsequent material deposition and bonding processes, eliminating the source of delamination and film peeling while maintaining electrical connectivity.
2Reliability
If the passivation layer is left intact, then structural continuity is maintained, but voids cause delamination and film peeling reducing package reliability
Solution Approach 1:
The passivation layer is segmented by forming a localized recess at the metal pad structure position, rather than maintaining continuous integrity. This segmentation allows the recess to be filled with bonding materials that prevent void formation, thereby maintaining overall structural stability while eliminating the harmful effects of voids that would cause delamination.
3Ease of manufacture
If voids are present in the passivation layer, then manufacturing is simpler, but delamination and film peeling occur causing debonding between IC dies
Solution Approach 1:
The recess formation is performed as a preliminary step before bonding via and bonding pad deposition. This preliminary cavity creation simplifies the overall manufacturing process by preventing void formation during material deposition, eliminating the need for complex void removal techniques while ensuring reliable die-to-die bonding.
Data Source
AI summary
A recess is formed through a passivation layer of an integrated circuit (IC) die and into an opening in a metal pad structure at the top of a seal ring structure of the IC die. The recess is formed to open up any voids that may have occurred in the passivation layer within the opening in the metal pad structure. This enables the recess (and thus, the void) to be filled in, which reduces the likelihood that the void might otherwise cause delamination and film peeling in the passivation layer. The recess (and thus, the void) may be filled in to form a bonding via and a bonding pad, which may be dummy structures or may be used to bond the IC die with another IC in the semiconductor die package.