Ceramic Substrate Trenching for Faster Electrode Patterning
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Solution Overview
Problem
Existing ceramic substrates face challenges in efficiently dissipating high heat generated by semiconductor chips in power modules due to limited heat dissipation capabilities of metal heat sinks and warping issues, which degrade performance and bonding characteristics.
Innovation Solution
A method involving bonding upper and lower metal layers to a ceramic material with a thickness range of 0.3 mm to 10 mm, forming trenches on the upper metal layer through mechanical processing, and using a photoresist or mask pattern for precise etching to create electrode patterns, with bonding layers made of Ag, AgCu, or AgCuTi for enhanced conductivity and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal heat sink is used for heat dissipation, then heat dissipation function is provided, but heat dissipation limit is reached and cooling efficiency drops sharply
Solution Approach 1:
The patent uses a composite structure combining ceramic substrate with metal heat sink and metal bonding layers. The ceramic substrate provides high-temperature resistance and mechanical strength, while the metal heat sink provides thermal conductivity for heat dissipation. This composite approach allows the system to achieve both high-temperature operation capability and effective heat dissipation, resolving the contradiction between heat dissipation capability and cooling efficiency reliability.
2Power
If semiconductor chip operates at high voltage and high current, then power conversion function is achieved, but high-temperature heat is generated causing chip deterioration
Solution Approach 1:
The patent introduces metal bonding layers as intermediaries between the semiconductor chip and the ceramic substrate. These bonding layers serve as thermal pathways to conduct heat away from the chip while maintaining electrical connectivity. The bonding layers act as mediators that enable both power transmission and heat dissipation, resolving the contradiction between high power conversion capability and heat generation management.
3Reliability
If metal layers are bonded to ceramic substrate, then electrical and thermal conductivity is enhanced, but warping occurs causing bonding characteristics to deteriorate
Solution Approach 1:
The patent carefully controls the thickness parameters of the metal bonding layers (0.3 mm to 10 mm range) and adjusts the bonding interface parameters to optimize both conductivity and warpage resistance. By optimizing these parameters, the patent achieves high electrical and thermal conductivity while minimizing thermal expansion differences that cause warping, thus maintaining bonding characteristics.
4Manufacturing precision
If conventional etching method is used to form electrode pattern, then patterning process is completed, but chemical etching time is long reducing productivity
Solution Approach 1:
The patent replaces conventional chemical etching with a mechanical processing approach using a trenching tool to create initial trenches in the metal layer. This mechanical method followed by photoresist masking and controlled etching significantly reduces the overall chemical etching time while maintaining precise electrode pattern formation. The mechanical pre-trenching creates guides that accelerate the subsequent chemical etching process, resolving the contradiction between pattern precision and etching speed.
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
This method reduces chemical etching time, improves patterning efficiency, enhances precision and quality of electrode patterns, and supports high heat dissipation and electrical conductivity for power modules, while minimizing warpage.
Implementation Method 1
melting the bonding layer to bond the ceramic material, the upper metal layer, and the lower metal layer to one another by brazing
Data Source
AI summary
The present invention relates to a method for manufacturing a ceramic substrate. Each of upper and lower metal layers respectively bonded to upper and lower surfaces of the ceramic substrate may have a thickness of 0.3 mm to 10 mm, so as to be applicable to a high output power module, and may reduce a chemical etching process time by performing, in advance, a trenching process, which is a mechanical processing scheme, in order to form an electrode pattern on the upper metal layer.