UTM Passivation Oxide Structure to Reduce Interface Cracking
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Solution Overview
Problem
The existing passivation layers in semiconductor devices with ultra-thick metal structures are prone to cracking due to stress concentration at film interfaces, leading to reduced yield and potential damage during manufacturing processes.
Innovation Solution
A modified passivation layer structure with reduced unbias films and minimized film interfaces, where the second and third passivation oxides are single films, positioned to avoid stress concentration points, thereby reducing cracking likelihood.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional passivation layer with multiple unbias films and dual film passivation oxides is used, then the protection function is provided, but cracking occurs due to stress concentration at film interfaces
Solution Approach 1:
The patent removes the unbias film from the passivation layer structure, extracting the source of stress concentration at film interfaces. This leaves only the bias film to provide protection, eliminating the cracking issue while maintaining the essential passivation function.
Solution Approach 2:
The patent merges the protection functions into a single bias film structure rather than using separate unbias and bias films. The bias film alone provides both the mechanical protection and stress management needed, consolidating the structure and eliminating interface-related cracking.
2Reliability
If multiple film interfaces are present in the passivation layer, then the layer provides comprehensive protection, but stress concentration at interfaces leads to cracking
Solution Approach 1:
The patent extracts and removes the unbias film that creates additional film interfaces. By eliminating this layer, the structure reduces the number of interfaces where stress concentration can occur, directly addressing the cracking problem while maintaining protection through the remaining bias film.
3Ease of manufacture
If the passivation layer includes unbias films and dual film structures, then coverage is provided, but manufacturing yield is reduced due to cracking
Solution Approach 1:
The patent extracts the unbias film from the manufacturing process, simplifying the passivation layer formation to deposit only the bias film. This reduction in process steps eliminates the cracking issue that reduced yield, while still providing adequate protection for the underlying structures.
Data Source
AI summary
A semiconductor device includes an ultra-thick metal (UTM) structure. The semiconductor device includes a passivation layer including a first passivation oxide. The first passivation oxide includes an unbias film and a first bias film, where the unbias film is on portions of the UTM structure and on portions of a layer on which the UTM structure is formed, and the first bias film is on the unbias film. The passivation layer includes a second passivation oxide consisting of a second bias film, the second bias film being on the first bias film. The passivation layer includes a third passivation oxide consisting of a third bias film, the third bias film being on the second bias film.