Si3N4 Ceramic Substrate Bonding via Laser Scribing and ZrO2 Blasting
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Solution Overview
Problem
Bonding defects between ceramic substrates made of silicon nitride and metal members, particularly due to the generation of silicon oxide gas during sintering, lead to insufficient bonding strength and reliability issues during thermal cycles.
Innovation Solution
A method involving the formation of scribe lines on ceramic substrates using energy light, followed by a surface treatment with ZrO2 powder to reduce silicon oxide and composite oxide concentrations to less than 2.7 Atom%, preventing gas generation and ensuring strong bonding between ceramic and metal members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the ceramic substrate is made of Si3N4 with better mechanical characteristics, then the bending strength is improved, but silicon oxide gas is generated during sintering which hinders bonding with metal members
Solution Approach 1:
The patent applies preliminary action by performing surface treatment (blast cleaning or chemical etching) on the ceramic substrate before bonding with metal members. This pre-treatment removes silicon oxide and composite oxide from the surface, preventing gas generation during subsequent bonding processes. The surface treatment is conducted in advance to ensure clean bonding surfaces, which resolves the contradiction between using high-strength Si3N4 ceramic and achieving reliable metal bonding.
2Strength
If silicon oxide and composite oxide are removed from the ceramic substrate surface, then bonding strength with metal members is improved, but additional surface treatment processes are required
Solution Approach 1:
The patent applies parameter changes by optimizing the sintering conditions (temperature, atmosphere, time) to minimize the formation of silicon oxide and composite oxide on the ceramic substrate surface. By controlling the sintering parameters, the amount of oxide formation is reduced, which in turn reduces the need for aggressive surface treatment. This approach balances bonding strength requirements with process simplicity.
3Reliability
If the concentration of silicon oxide and composite oxide is reduced to less than 2.7 Atom%, then gas generation during bonding is prevented, but precise control of oxide concentration is required
Solution Approach 1:
The patent applies feedback by implementing a systematic approach to monitor and control oxide concentration on the ceramic substrate surface. The method involves measuring oxide concentration (using techniques like XPS or SIMS) and adjusting surface treatment parameters or sintering conditions based on the measured values to ensure oxide concentration remains below the 2.7 Atom% threshold. This feedback mechanism ensures reliable bonding while managing the precision requirements.
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 approach enhances the bonding strength between ceramic substrates and metal members, preventing peeling and ensuring reliable bonding during thermal cycles, even under repeated heating and cooling loads.
Implementation Method 1
radiating energy light to the surface of a ceramic base material including silicon to form scribe lines in the surface of the ceramic base material
Implementation Method 2
the surface treatment is a blast process of blowing ZrO2 powder to the upper and lower surfaces of the ceramic base material
Implementation Method 3
brazing metal members to the ceramic substrate
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(d)
AI summary
Disclosed is a ceramic substrate including silicon in which the concentration of a silicon oxide and a silicon composite oxide in the surface thereof is less than or equal to 2.7 Atom%.