Semiconductor Package Pad Structure for Thermal and Physical Stress Resistance
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Solution Overview
Problem
Conventional semiconductor packages and module printed circuit boards (PCBs) face challenges in resisting both physical and thermal stresses, leading to potential separation of conductive pads and cracks in the circuit substrate due to unreliable cohesion and material flexibility, which affects the reliability of the semiconductor package and PCB.
Innovation Solution
The implementation of a dual pad structure on both the semiconductor package and module PCB, where first-type pads with an insulating layer and exposed sidewalls provide resistance to physical stress, and second-type pads with a conventional NSMD structure offer resistance to thermal stress, thereby enhancing overall reliability by distributing stress effectively across different regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If NSMD pad structure is used with conductive pad spaced from insulating layer, then thermal stress resistance is improved, but physical stress resistance deteriorates due to unreliable cohesion
Solution Approach 1:
The patent applies different pad structures in different regions: NSMD structure in the first region for thermal stress resistance, and SMD structure in the second region for physical stress resistance. This spatial differentiation of structural properties resolves the contradiction by optimizing each region for its specific stress condition.
2Strength
If SMD pad structure is used with insulating layer overlapping conductive pad, then physical stress resistance is improved, but thermal stress resistance deteriorates due to stress concentration
Solution Approach 1:
The patent implements SMD pad structure specifically in the second region where physical stress resistance is prioritized, while maintaining NSMD structure in the first region for thermal stress resistance. This localized application resolves the contradiction by matching structure to functional requirement.
3Ease of manufacture
If module PCB is made of flexible material, then ease of manufacture is improved, but reliability deteriorates due to warpage and twist causing pad separation and substrate cracks
Solution Approach 1:
The patent differentiates pad structures based on their functional requirements: NSMD for thermal stress resistance and SMD for physical stress resistance. This localized optimization allows the flexible PCB to maintain reliability despite warpage and twist by ensuring each pad type is suited to its stress environment.
Data Source
AI summary
Provided are a semiconductor package and a module printed circuit board (PCB) for mounting the same. Each of the semiconductor package and the module PCB includes a substrate, a first-type pad structure disposed in a first region of the substrate, and a second-type pad structure disposed in a second region of the package substrate. The first-type pad includes a first conductive pad disposed on the package substrate and a first insulating layer coated on the package substrate. The first insulating layer has a first opening by which a portion of a sidewall of the first conductive pad is exposed, and partially covers the first conductive pad. The second-type pad includes a second insulating layer coated on the package substrate to have a second opening and a second conductive pad disposed on the package substrate in the second opening to have an exposed sidewall. In this structure, the semiconductor package and the module PCB can have an excellent resistance to physical and thermal stresses to enhance structural reliability.