Semiconductor Interposer Underfilling for Mixed Package Reliability
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Solution Overview
Problem
Semiconductor devices with components of different package structures and bump electrode heights face reliability issues due to stress-induced damage and disconnection failures during thermal cycles and screening tests, particularly with the CSP structure experiencing solder flush and short circuit defects.
Innovation Solution
Implementing different under-filling materials and designs between the substrate and semiconductor components of varying package structures, specifically using under-filling 4a for WPP and under-filling 4b for CSP structures, each with unique properties such as thermal expansion coefficients and adhesive strengths, to mitigate stress and prevent solder flush and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the same under-filling material is used for both WPP and CSP semiconductor components, then the manufacturing process is simplified, but stress-induced damage and disconnection failures occur due to different thermal expansion coefficients and height differences
Solution Approach 1:
The patent applies different under-filling materials (first under-filling for WPP components, second under-filling for CSP components) tailored to the specific requirements of each component type. This local differentiation allows each under-filling material to be optimized for its corresponding component's thermal expansion characteristics and height, thereby preventing stress-induced damage while maintaining manufacturing feasibility.
Solution Approach 2:
The patent changes the parameters of the under-filling materials by selecting materials with different thermal expansion coefficients and physical properties for WPP and CSP components. This parameter differentiation resolves the contradiction by allowing each under-filling material to match the thermal and mechanical characteristics of its target component, preventing reliability issues without overly complicating the manufacturing process.
2Reliability
If under-filling is used for CSP structures with large bump electrode pitch, then stress is reduced, but solder flush and short circuit defects occur due to material flow between bump electrodes
Solution Approach 1:
The patent applies a specific second under-filling material with controlled viscosity and curing characteristics for CSP components. This material is specifically selected to have appropriate flow properties that provide stress mitigation while preventing excessive flow that would cause solder flush. The local optimization of under-filling material properties for CSP structures resolves the contradiction between stress reduction and short circuit prevention.
3Reliability
If different under-filling materials are used for WPP and CSP structures, then reliability is improved by addressing specific component requirements, but device complexity increases
Solution Approach 1:
The patent segments the under-filling process into two distinct material applications: first under-filling for WPP components and second under-filling for CSP components. This segmentation allows each material to be optimized for its specific component type while maintaining clear process boundaries. The segmentation approach manages complexity by creating distinct, well-defined material applications rather than requiring a single complex material to satisfy all requirements.
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
Enhances the reliability of semiconductor devices by preventing damage and disconnection failures in both WPP and CSP structures, improving the integrity of bump electrodes and reducing short circuit defects during thermal stress and screening tests.
Implementation Method 1
each with unique properties such as thermal expansion coefficients and adhesive strengths, to mitigate stress
Data Source
AI summary
The reliability of a semiconductor device which has the semiconductor components which were mounted on the same surface of the same substrate via the bump electrodes with which height differs, and with which package structure differs is improved. Semiconductor component 2 of WPP structure is mounted on the main surface of the interposer substrate which forms a semiconductor device via a plurality of bump electrodes. Semiconductor component 3 of CSP structure is mounted on the main surface of an interposer substrate via a plurality of bump electrodes with larger diameter and contiguity pitch than the above-mentioned bump electrode. And under-filling 4a and 4b mutually different, are filled up between the facing surfaces of this interposer substrate and semiconductor components 2, and between the facing surfaces of the interposer substrate and semiconductor components 3, respectively.