Metallized Nitride Ceramic Substrate Adhesion and Conductivity
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Solution Overview
Problem
Existing methods for forming metal wiring on sintered nitride ceramic substrates face challenges with high wiring resistance and adhesion strength, particularly when using thick-film methods, and there is a need for improved platability and electrical conductivity.
Innovation Solution
A production method involving a sintered nitride ceramic substrate with a titanium nitride layer and a metal layer composed of copper, silver, and titanium, achieved by layering a first paste containing copper powder and titanium hydride, followed by a second paste layer with silver-copper alloy powder, and firing in a non-oxidizing atmosphere to enhance adhesion and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick-film method with high-melting-point metal paste is used to form metal wiring on nitride ceramic substrate, then adhesion strength is improved, but wiring resistance increases
Solution Approach 1:
The metal wiring is divided into multiple layers with different functions: a lower metal layer (e.g., tungsten, molybdenum) provides strong adhesion to the nitride ceramic substrate, while an upper metal layer (e.g., copper, silver) provides low wiring resistance. This segmentation allows each layer to optimize its properties without compromising the other.
Solution Approach 2:
The invention uses composite metal structures combining different metal materials. The lower layer uses high-melting-point metals for adhesion, while the upper layer uses low-resistance metals for electrical conductivity. This composite approach resolves the contradiction between adhesion strength and wiring resistance.
2Reliability
If a thin-film method is used to form metal wiring on nitride ceramic substrate, then wiring resistance is reduced, but the amount of electric current permitted to flow is limited
Solution Approach 1:
The solution transitions from a two-dimensional thin film to a three-dimensional multi-layer structure. By adding vertical dimension with multiple metal layers, the patent achieves both low resistance (like thin film) and high current capacity (like thick film), resolving the contradiction between wiring resistance and current handling capability.
3Manufacturing precision
If post-firing method is used to form high-melting-point metal layer on nitride ceramics, then dimensional precision is improved, but adhesion strength deteriorates
Solution Approach 1:
The patent applies metal paste to the nitride ceramic green sheet before sintering (preliminary action). During the sintering process, the metal particles are embedded into the ceramic matrix, creating strong mechanical interlocking and chemical bonding. This preliminary application ensures both dimensional precision and strong adhesion.
Solution Approach 2:
The invention merges the ceramic sintering process with the metal firing process into a single co-firing operation. The metal paste and ceramic green sheet are processed together, allowing the metal to bond with the ceramic during sintering, thereby achieving both dimensional accuracy and strong adhesion simultaneously.
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 method reduces wiring resistance, improves adhesion strength, and enhances platability and thermal conductivity of the metallized substrate, allowing for the formation of precise and fine wiring patterns with improved surface smoothness.
Implementation Method 1
a titanium nitride layer (60) formed on the sintered substrate (10)
Implementation Method 2
a step of firing the second layered body (110), to thereby form the titanium nitride layer (60) and the metal layer (50) on the sintered nitride ceramic substrate (10)
Data Source
AI summary
A production method for a metallized substrate to produce a metallized substrate which comprises: a sintered nitride ceramic substrate; a titanium nitride layer formed on the sintered substrate; and a metal layer containing copper, silver and titanium formed on the titanium nitride layer. The method comprises: a step of layering a first paste layer containing copper powder and titanium hydride powder on the sintered nitride ceramic substrate, to produce a first layered body; a step of layering a second paste layer containing silver-copper alloy powder on the first paste layer of the first layered body, to produce a second layered body; and a step of firing the second layered body, to thereby form the titanium nitride layer and the metal layer on the sintered nitride ceramic substrate.