Ceramic Circuit Substrate Brazing Deposit Removal
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Solution Overview
Problem
The production of ceramic circuit substrates by brazing methods often results in insulation-resistance-decreasing deposits on ceramic substrate surfaces, which are difficult to remove and lead to defects in appearance and electrical insulation, especially when using silicon nitride ceramics with columnar grains.
Innovation Solution
A method involving the formation of brazing regions on a ceramic substrate, bonding metal plates via the brazing material, and cleaning the bonded body with a hypochlorite-containing agent to remove or decrease the deposits, ensuring high insulation resistance between metal plates and minimizing surface deposits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If brazing material paste with organic binder is heated to bond metal plates to ceramic substrate, then bonding strength is improved, but carbon-based adhesive deposits are formed on exposed ceramic surfaces
Solution Approach 1:
The patent employs an oxidizing atmosphere during the heating process to oxidize and remove carbon-based deposits from the ceramic substrate surface. The oxidizing environment converts the harmful carbon deposits into volatile carbon oxides that are removed during heating, thereby preventing deposit formation while maintaining the brazing bonding strength.
2Object-generated harmful factors
If deposits are removed by etching solution or brazing-material-removing liquid, then appearance defects are reduced, but insulation resistance decreases and metal plates are eroded
Solution Approach 1:
The patent performs deposit removal during the heating process itself by controlling the atmosphere to be oxidizing. This preliminary action prevents deposits from accumulating on the ceramic surface before the brazing is complete, eliminating the need for subsequent chemical etching or removing treatments that would compromise insulation resistance and erode metal plates.
3Object-generated harmful factors
If heating time is extended to remove deposits completely, then appearance quality is improved, but resist and metal plates are damaged
Solution Approach 1:
By creating an oxidizing atmosphere during heating, the patent accelerates the oxidation and removal of carbon-based deposits. This allows for effective deposit removal within the standard brazing time frame without requiring extended heating that would damage the resist and metal plates. The oxidizing environment ensures deposits are converted and removed as volatile products during the normal heating cycle.
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 effectively removes or decreases insulation-resistance-decreasing deposits, achieving a ceramic circuit substrate with improved electrical insulation and reduced appearance defects, maintaining the integrity of the ceramic substrate and metal plates.
Implementation Method 1
cleaning the bonded body with a hypochlorite-containing agent. The organic binder contained in the brazing material paste is decomposed and gasified in the heating process of the bonded body, so that it is removed from the brazing material paste. However, part of the gasified organic binder is likely deposited onto exposed surfaces of the ceramic substrate, which are not covered with the metal plates, forming carbon-based adhesive deposits.
Implementation Method 2
The organic binder contained in the brazing material paste is decomposed and gasified in the heating process of the bonded body, so that it is removed from the brazing material paste.
Implementation Method 3
heating the bonded body at a brazing-material-melting temperature in vacuum or in non-oxidizing state to bond the metal plates to the ceramic substrate via the brazing material
Data Source
AI summary
A method for producing a ceramic circuit substrate comprising the steps of forming brazing regions each comprising brazing material powder and an organic binder on a ceramic substrate; setting metal plates on the ceramic substrate via the brazing regions, and heating the ceramic substrate, the brazing regions and the metal plates to bond the metal plates to the ceramic substrate via brazing layers made of the brazing material, thereby forming a bonded body; and cleaning the bonded body with a hypochlorite-containing agent.