Semiconductor Package Pad Structure for Thermal Stress Relief
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Solution Overview
Problem
The increase in high-bandwidth memory demand and larger semiconductor package sizes due to high specification sets leads to thermal stress issues caused by coefficient of thermal expansion differences, increasing process difficulty and reducing yield.
Innovation Solution
Incorporating a semiconductor package design with a first pad having a center pad and an edge pad, where the edge pad has a lower elastic modulus than the center pad, surrounded by a passivation film, to relax thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of semiconductor packages is enlarged to meet high specification demands, then the capacity and bandwidth are improved, but the thermal stress caused by coefficient of thermal expansion differences increases
Solution Approach 1:
The pad structure is divided into two regions with different elastic moduli: a center pad region with high elastic modulus for electrical connection and an edge pad region with low elastic modulus for stress relaxation. This local differentiation allows the package to simultaneously achieve high capacity and reduced thermal stress.
Solution Approach 2:
The pad structure combines materials or regions with different elastic moduli to create a composite structure. The center pad uses a rigid material for electrical conductivity while the edge pad uses a flexible material for stress absorption, resolving the contradiction between structural integrity and stress resistance.
2Productivity
If the size of semiconductor packages is enlarged, then the bandwidth is improved, but the process difficulty increases
Solution Approach 1:
By differentiating the pad into center and edge regions with distinct properties, the manufacturing process can target specific areas for stress management without affecting the overall electrical connection functionality, simplifying the manufacturing of large-scale packages.
3Quantity of substance
If the size of semiconductor packages is enlarged, then the memory capacity is improved, but the yield decreases
Solution Approach 1:
The low elastic modulus edge pad acts as a pre-designed stress absorption zone that cushions thermal stress before it can propagate to critical components. This preventive stress management protects against manufacturing defects and improves yield in large-scale packages.
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
Reduces thermal stress on the passivation film by up to 42% by using an edge pad with a specific width and elastic modulus, improving package performance and reliability.
Implementation Method 1
an edge pad having a second elastic modulus smaller than the first elastic modulus, the edge pad formed to surround the center pad and to contact the passivation film
Data Source
AI summary
The present disclosure provides a semiconductor package capable of improving performance and reliability. The semiconductor package of the present disclosure includes a first device and a second device that are electrically connected to each other, the first device includes a substrate, a first pad formed on an upper side of the substrate, and a passivation film formed on the upper side of the substrate and formed to surround the first pad, the second device includes a second pad placed to face the first pad, and the first pad has a center pad having a first elastic modulus and an edge pad having a second elastic modulus smaller than the first elastic modulus, the edge pad formed to surround the center pad and to contact the passivation film.