Electrode Structure Ground Metallic Layer Stress Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor device structures face challenges in controlling crack and peeling issues due to stress concentration at the root portions of metallic bumps, especially with miniaturization and the use of materials with low dielectric constants, leading to reliability concerns.
Innovation Solution
The electrode structure includes a semiconductor chip with a ground metallic layer positioned within an opening of a second insulation film, where the ground metallic layer's outer diameter is smaller than the electrode pad's, and the second opening's diameter is larger than the ground metallic layer's, allowing for a sufficient gap to be filled with under-fill resin and filler, thereby reducing stress and preventing crack and peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ground metallic layer is formed to extend to the periphery of the electrode pad to increase grounding area, then the grounding effect is improved, but stress concentration occurs at the end portions of the ground metallic layer causing cracks and peeling
Solution Approach 1:
The patent applies local quality by making the ground metallic layer asymmetric: it extends to the periphery of the electrode pad in some areas to provide grounding, but is intentionally recessed from the periphery in other areas (where the opening of the second insulation film is larger than the outer peripheral diameter of the ground metallic layer) to avoid stress concentration. This localized variation in the ground metallic layer's extent resolves the contradiction between achieving adequate grounding area and preventing stress-induced cracks and peeling.
2Strength
If the gap between semiconductor chip and wiring substrate is filled with under-fill resin to reduce stress concentration, then bonding strength is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the ground metallic layer with a specific configuration (recessed from the periphery in certain areas) before the flip-chip mounting process. This preliminary structural preparation ensures that stress is naturally distributed more evenly, reducing the critical need for under-fill resin to prevent stress concentration. While under-fill resin is still used to fill the gap and improve bonding strength, the pre-configured ground metallic layer reduces the overall manufacturing complexity by eliminating the need for more complex stress-management techniques.
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 controls crack and peeling generation, enhances bonding strength, and improves the reliability of semiconductor devices by ensuring the gap is filled with under-fill resin and filler, reducing stress transmission and peeling risks.
Implementation Method 1
the under-fill resin 8 is injected from a periphery of the chip, and capillarity makes the under-fill resin 8 spread onto an entire bottom surface of the semiconductor chip 1
Implementation Method 2
In the under-fill resin 8, filler 9 having an appropriate size is added to resin 8a, which is a base material such as epoxy-based resin, in order for the under-fill resin 8 to obtain a thermal expansion coefficient similar to that of the semiconductor chip 1
Data Source
AI summary
A first insulation film having a first opening is provided on an electrode pad of a semiconductor chip. A second insulation film having a second opening is provided on the first insulation film. A ground metallic layer which is to be in contact with the electrode pad via the first opening is provided on the first insulation film. A bump which is to be mechanically and electrically connected to the ground metallic layer is provided. Further, the above placement is made in a way that the ground metallic layer is provided in the second opening, and the ground metallic layer is provided on an inner side than an outer periphery of the electrode pad, covering the first opening.