Metal Bump Shape Control via Non-Planar Passivation
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Solution Overview
Problem
Shape abnormalities in metal bumps of semiconductor devices can lead to yield drops, process failures, and inferior electrical characteristics, necessitating the formation of metal bumps without such abnormalities during semiconductor manufacturing.
Innovation Solution
A semiconductor device with a metal terminal on a passivation layer having a non-planarized top surface with flat surfaces on metal lines and a concave surface between them, where the metal terminal's opposite lateral surfaces face each other on the flat surfaces of the passivation layer, preventing abnormal shape formation and electrical shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a planarized passivation layer is used to form metal bumps, then the manufacturing process becomes more complex and productivity decreases, but the metal bump shape uniformity improves
Solution Approach 1:
The patent extracts and eliminates the planarization process from the manufacturing flow. By forming metal terminals directly on the non-planar passivation layer surface, the invention removes the unnecessary planarization step that was previously required, thereby simplifying the process and improving productivity while maintaining bump shape uniformity through the natural flat surfaces formed during passivation layer deposition
Solution Approach 2:
The patent inverts the conventional approach by not planarizing the passivation layer before forming metal terminals. Instead of making the surface flat through additional processing, the invention accepts the non-planar surface and forms metal terminals that utilize the inherent flat regions, thereby inverting the problem-solving approach from 'make surface flat' to 'form terminals on non-planar surface'
2Productivity
If metal terminals are formed on a non-planar passivation layer, then the manufacturing process is simplified and productivity increases, but the metal terminal shape may become abnormal
Solution Approach 1:
The patent applies local quality by forming metal terminals specifically on the flat surface regions of the non-planar passivation layer rather than uniformly across the entire surface. The flat surfaces, which naturally form over the metal lines during passivation layer deposition, provide localized suitable regions for metal terminal formation, ensuring shape uniformity while maintaining overall process simplicity
Solution Approach 2:
The passivation layer deposition process naturally creates flat surfaces over the metal lines without requiring additional planarization. The invention utilizes this self-formed flat surface characteristic to provide suitable formation regions for metal terminals, allowing the passivation layer to serve dual purposes: protecting the structure and providing formation surfaces for subsequent metal terminals
3Reliability
If the passivation layer is planarized, then the metal terminal formation process becomes more complex, but electrical shorts between adjacent metal terminals are prevented
Solution Approach 1:
The patent performs preliminary action by forming the passivation layer with sufficient thickness during the deposition process to naturally create flat surfaces that provide adequate separation between adjacent metal terminals. This preliminary formation of isolation regions during passivation layer deposition eliminates the need for subsequent planarization steps while maintaining electrical isolation reliability
Data Source
AI summary
Provided are a semiconductor device and a method of manufacturing the same. The semiconductor device includes a metal line layer on a semiconductor substrate, and a metal terminal on the metal line layer. The metal line layer includes metal lines, and a passivation layer having a non-planarized top surface including flat surfaces on the metal lines and a concave surface between the metal lines. The metal terminal is provided on the passivation layer. Opposite lateral surfaces of the metal terminal facing each other are provided on the flat surfaces of the passivation layer.