Semiconductor Pillar Electrode Stress Buffering via Resin Film
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Solution Overview
Problem
The reliability of semiconductor devices with flip-chip bonded semiconductor chips over printed circuit boards is compromised due to stress applied from pillar electrodes to interlayer insulation films, which can lead to damage and degradation, especially when using low-dielectric insulation films.
Innovation Solution
Optimizing the thickness and diameter of pillar electrodes and the thickness of the solder layer, ensuring the pillar electrode thickness is between half and twice the solder layer thickness, and the sum of these dimensions is between 0.5 and 0.8 times the pillar electrode diameter, while using a laminate insulation structure with a resin film as a stress buffer layer to absorb stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pillar electrodes are used to connect semiconductor chip to printed circuit board, then electrical connection is achieved, but stress is applied to interlayer insulation films causing damage and degradation
Solution Approach 1:
A resin film is introduced as an intermediary stress buffer layer between the pillar electrode and the interlayer insulation film. This resin film absorbs the stress generated by the pillar electrode, preventing direct transmission of stress to the interlayer insulation film and thereby avoiding damage and degradation while maintaining electrical connection reliability
Solution Approach 2:
The patent employs a composite structure consisting of the pillar electrode, resin film stress buffer layer, and interlayer insulation film. This composite material approach allows the resin film to specifically address the stress issue while the other layers maintain their respective functions, resolving the contradiction between connection reliability and stress protection
2Object-affected harmful factors
If pillar electrode thickness is increased to reduce stress, then stress buffer capacity improves, but device size increases
Solution Approach 1:
The resin film acts as a dedicated stress buffer intermediary, allowing the pillar electrode to maintain its electrical connection function without needing to increase in thickness for stress management. The stress buffering function is separated to the resin film layer, enabling the pillar electrode to remain compact while still protecting the interlayer insulation film from stress
Solution Approach 2:
The stress buffering function is segmented from the pillar electrode structure and assigned to a separate resin film layer. This segmentation allows the pillar electrode to focus on electrical connection with optimized minimal thickness, while the resin film specifically handles stress absorption, preventing the need to increase pillar electrode volume
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 reduces stress on interlayer insulation films, enhancing the reliability of semiconductor devices by preventing damage and supporting miniaturization and multiterminal configurations.
Implementation Method 1
using a laminate insulation structure with a resin film as a stress buffer layer to absorb stress
Implementation Method 2
The pillar electrode of the semiconductor chip and the terminal of the printed circuit board are coupled via a solder layer
Data Source
AI summary
There is a need to improve reliability of the semiconductor device.A semiconductor device includes a printed circuit board and a semiconductor chip mounted over the printed circuit board. The semiconductor chip includes a pad, an insulation film including an opening to expose part of the pad, and a pillar electrode formed over the pad exposed from the opening. The printed circuit board includes a terminal and a resist layer including an opening to expose part of the terminal. The pillar electrode of the semiconductor chip and the terminal of the printed circuit board are coupled via a solder layer. Thickness h1 of the pillar electrode is measured from the upper surface of the insulation film. Thickness h2 of the solder layer is measured from the upper surface of the resist layer. Thickness h1 is greater than or equal to a half of thickness h2 and is smaller than or equal to thickness h2.