Bonding Pad Protective Film Layout for Moisture-Resistant ICs
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Solution Overview
Problem
High moisture permeability through organic insulating films in semiconductor integrated circuits leads to insufficient moisture resistance, especially at bonding pads, where adhesion between inorganic and Au bonding pads is low, causing potential moisture penetration and hindering circuit reliability.
Innovation Solution
A semiconductor integrated circuit design featuring a second inorganic protective film with end portions extending between wiring lines and bonding pads, forming a larger contact area with the organic protective film to enhance moisture resistance without increasing bonding pad size, and using adhesion-enhancing films to prevent peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an organic insulating film is used to reduce wiring delays, then wiring speed is improved, but moisture resistance deteriorates
Solution Approach 1:
The patent uses a composite structure combining organic insulating film (for low dielectric constant and high wiring speed) with inorganic insulating film (for high moisture resistance). The inorganic film is selectively formed in regions where moisture resistance is critical, creating a multi-material system that achieves both high speed and reliability.
Solution Approach 2:
The inorganic insulating film is not formed uniformly across the entire chip but is selectively applied to specific regions such as bonding pad areas and regions adjacent to circuit elements where moisture penetration risk is highest. This localized approach maintains moisture resistance where needed while preserving the low dielectric constant properties of the organic film in other areas.
2Reliability
If bonding pad area is increased to improve moisture resistance, then moisture resistance is improved, but bonding region area is reduced
Solution Approach 1:
The inorganic insulating film is selectively formed around bonding pads and in regions where moisture resistance is critical, rather than increasing the bonding pad area itself. This localized protection approach provides enhanced moisture resistance without encroaching on the bonding region area, allowing full utilization of the bonding pad surface for electrical connections.
3Strength
If adhesion enhancing film is inserted between bonding pads and inorganic insulating film, then adhesion is improved, but device complexity increases
Solution Approach 1:
The patent introduces an adhesion enhancing film as an intermediary layer between the bonding pads and the inorganic insulating film. This intermediate layer improves the adhesion between materials that would otherwise have poor bonding, preventing delamination and moisture penetration at the interface.
Solution Approach 2:
The patent employs a multi-layer composite structure at the bonding pad region, combining the adhesion enhancing film with the inorganic insulating film and bonding pad materials. This composite approach addresses the adhesion problem while integrating multiple functions (adhesion enhancement, moisture barrier, and electrical isolation) into a unified structure.
Data Source
AI summary
A second protective film is formed on and in contact with a first protective film, and is formed to cover the first protective film. The second protective film is also formed so that an end portion extending toward the center of a first opening is interposed between a wiring line and a bonding pad at the edge portion of the bonding pad.