Ceramic-Copper Substrate Grain Control for Thermal Bond Reliability
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Solution Overview
Problem
The increasing junction temperature of semiconductor devices due to higher performing semiconductor elements, coupled with the thermal expansion of thicker copper circuit boards, affects the reliability of bonds and heat dissipation in ceramic copper circuit boards.
Innovation Solution
A ceramic copper circuit board design with a copper circuit board thickness ratio of 1.25 times or more than the ceramic substrate thickness, controlled grain boundaries (20-250 per 10-mm straight line), and a bonding layer of Ag-Ti alloy, ensuring improved thermal expansion matching and anchor effect for reliable bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the copper circuit board thickness is increased to improve heat dissipation, then the heat dissipation performance is improved, but the thermal expansion causes deterioration in bond reliability
Solution Approach 1:
The patent controls the grain boundary number (20-250 per 10mm) and thickness ratio (1.25 or more) as key parameters to resolve the contradiction between heat dissipation and bond reliability, transforming the copper plate's microstructure to achieve both thermal performance and bonding strength
Solution Approach 2:
The patent creates a composite structure by bonding the copper circuit board to the ceramic substrate with controlled grain boundaries, combining the high thermal conductivity of copper with the dimensional stability of ceramic to achieve both heat dissipation and bond reliability
2Reliability
If the grain boundary number in the copper circuit board is increased to improve bondability, then the bondability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent establishes a specific grain boundary number range (20-250 per 10mm) that optimizes bondability while maintaining manufacturing feasibility, avoiding excessive complexity by defining clear parameter boundaries
3Temperature
If the thickness ratio of copper circuit board to ceramic substrate is increased to improve heat dissipation, then the heat dissipation is improved, but the thermal stress increases
Solution Approach 1:
The patent optimizes the thickness ratio parameter (1.25 or more) and combines it with grain boundary control to manage thermal stress while maintaining effective heat dissipation, balancing thermal performance with structural integrity
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 and heat dissipation of semiconductor devices by maintaining bond integrity and reducing thermal stress, allowing for high junction temperatures and efficient heat management.
Implementation Method 1
controlled grain boundaries (20-250 per 10-mm straight line), and a bonding layer of Ag-Ti alloy, ensuring improved thermal expansion matching and anchor effect for reliable bonding
Implementation Method 2
A ceramic copper circuit board design with a copper circuit board thickness ratio of 1.25 times or more than the ceramic substrate thickness, controlled grain boundaries (20-250 per 10-mm straight line), and a bonding layer of Ag-Ti alloy, ensuring improved thermal expansion matching and anchor effect for reliable bonding
Implementation Method 3
controlled grain boundaries (20-250 per 10-mm straight line), and a bonding layer of Ag-Ti alloy, ensuring improved thermal expansion matching and anchor effect for reliable bonding
Data Source
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AI summary
A ceramic-copper circuit substrate according to an embodiment of the present invention includes a ceramic substrate, and a copper circuit board disposed on one surface of the ceramic substrate. The present invention is characterized by the following: the proportion of the thickness of the copper circuit board to that of the ceramic substrate is at least 1.25; and the number of grain boundaries even on 10mm of any straight line drawn on the surface of the copper circuit board is 5 to 250.