Semiconductor Post Bump Peripheral Edge Deformation for Passivation Crack Prevention
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Solution Overview
Problem
The existing WL-CSP semiconductor device technology faces challenges in preventing crack formation in the passivation film due to stress concentration at the peripheral edge of the barrier film and post bump, which leads to increased manufacturing steps and device thickness when using a polyimide layer for stress absorption.
Innovation Solution
A semiconductor device configuration where a post bump with a protruding peripheral edge is formed on an interposing film, allowing the edge to deform and absorb stress without the need for a polyimide layer, thereby preventing crack formation in the passivation film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyimide layer is added to absorb stress and prevent crack formation in the passivation film, then the reliability of the passivation film is improved, but the device complexity and manufacturing cost increase due to additional manufacturing steps
Solution Approach 1:
The invention extracts the stress absorption function from a separate polyimide layer and integrates it into the barrier film structure itself. The barrier film is designed with a specific configuration that allows it to absorb stress directly, eliminating the need for the additional polyimide layer while maintaining crack prevention capability in the passivation film.
Solution Approach 2:
The invention merges the stress absorption function with the barrier film by positioning it between the post bump and the passivation film. This combination allows the barrier film to simultaneously serve as both a protective barrier and a stress-absorbing element, eliminating the need for separate stress management layers.
2Reliability
If a polyimide layer is added to absorb stress and prevent crack formation in the passivation film, then the reliability of the passivation film is improved, but the device thickness increases
Solution Approach 1:
The invention extracts the stress absorption function from a separate polyimide layer and integrates it into the barrier film structure itself. The barrier film is designed with a specific configuration that allows it to absorb stress directly, eliminating the need for the additional polyimide layer while maintaining crack prevention capability in the passivation film.
Solution Approach 2:
The invention merges the stress absorption function with the barrier film by positioning it between the post bump and the passivation film. This combination allows the barrier film to simultaneously serve as both a protective barrier and a stress-absorbing element, eliminating the need for separate stress management layers.
3Stability of the object's composition
If the peripheral edge portion of the barrier film is positioned on the passivation film, then the structural integrity is maintained, but stress concentration occurs leading to crack formation in the passivation film
Solution Approach 1:
The invention introduces an intermediary configuration of the barrier film that positions its peripheral edge portion on the interposing film rather than directly on the passivation film. This intermediary positioning allows the barrier film to absorb stress through its own deformation, preventing stress concentration in the passivation film while maintaining structural integrity.
Solution Approach 2:
The invention changes the positioning parameter of the barrier film's peripheral edge portion from being on the passivation film to being on the interposing film. This parameter change alters the stress distribution pattern, allowing the barrier film to absorb stress through deformation without transmitting concentrated stress to the passivation film.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively absorbs stress without increasing manufacturing steps or device thickness, preventing crack formation in the passivation film while maintaining the semiconductor device's functionality and efficiency.
Implementation Method 1
the peripheral edge portion of the post bump is deformable in a direction opposing the passivation film. Thus, even when stress concentrates at the peripheral edge portions of the post bump and the barrier film, the stress is absorbed by deformation of the peripheral edge portion of the post bump
Data Source
AI summary
A semiconductor chip includes a substrate, an electrode pad formed on the substrate, an insulating layer covering the substrate and the electrode pad, and having an opening exposing a portion of a surface of the electrode pad, a first conductive layer formed on the exposed portion of the surface of the electrode pad and extending to a surface of the insulating layer, and a second conductive layer formed on the first conductive layer, covering the first conductive layer in a plan view, and having an outer edge portion which is located further out than an outer edge of the first conductive layer in a plan view. The outer edge portion of the second conductive layer has at least one curved portion. At least one portion of the curved portion is located between the outer edge of the first conductive layer and an outer edge of the second conductive layer in a plan view.