Twinned Copper Conductive Layers for Semiconductor Package Thermal Stress
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable semiconductor devices as feature sizes continue to decrease, leading to increased complexity and difficulty in fabrication processes, particularly due to thermal stress at the interface between chip structures and molding layers.
Innovation Solution
The use of twinned copper in conductive layers and structures, formed through a process involving pulse electroplating and direct current electroplating, which enhances the mechanical properties such as Young's modulus and tensile strength, thereby reducing the likelihood of cracking and improving yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but fabrication process difficulty and reliability increase
Solution Approach 1:
The patent changes the material parameter from conventional copper to twinned copper, which has superior mechanical properties including higher Young's modulus and tensile strength. This material parameter change enables the fabrication process to maintain reliability at smaller feature sizes while preserving production efficiency.
Solution Approach 2:
The patent employs twinned copper as a composite material structure with enhanced mechanical properties. The twinned crystal structure provides both the electrical conductivity needed for interconnects and the mechanical strength required to withstand thermal stress during fabrication, thereby reducing process complexity and improving yield.
2Ease of manufacture
If conventional copper is used in conductive structures, then manufacturing is easier, but thermal stress resistance and reliability deteriorate
Solution Approach 1:
The patent uses twinned copper as a composite material structure that combines the ease of electroplating manufacturing with enhanced mechanical properties. The twinned crystal structure develops during electroplating, providing both manufacturability and superior thermal stress resistance.
Solution Approach 2:
The patent changes the material parameter from conventional copper to twinned copper, which has superior mechanical properties including higher Young's modulus and tensile strength. This material parameter change enables the fabrication process to maintain reliability at smaller feature sizes while preserving production efficiency.
3Ease of manufacture
If standard copper conductive layers are used, then manufacturing cost is lower, but cracking resistance and yield improve less
Solution Approach 1:
The patent changes the material parameter from conventional copper to twinned copper, which has superior mechanical properties including higher Young's modulus and tensile strength. This material parameter change enables the fabrication process to maintain reliability at smaller feature sizes while preserving production efficiency.
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
The implementation of twinned copper in semiconductor package structures improves the reliability and yield of conductive lines by withstanding greater thermal stress, allowing for increased layout flexibility and reduced risk of cracking, thus addressing the challenges of miniaturization in semiconductor fabrication.
Implementation Method 1
The use of twinned copper in conductive layers and structures, formed through a process involving pulse electroplating and direct current electroplating
Data Source
AI summary
A semiconductor package structure is provided. The semiconductor package structure includes a chip structure. The semiconductor package structure includes a first conductive structure over the chip structure. The first conductive structure is electrically connected to the chip structure. The first conductive structure includes a first transition layer over the chip structure; a first conductive layer on the first transition layer; and a second conductive layer over the first conductive layer. The first conductive layer is substantially made of twinned copper. A first average roughness of a first top surface of the second conductive layer is less than a second average roughness of a second top surface of the first conductive layer.