Ceramic Circuit Substrate Edge Brazing Gap Design

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Solution Overview

Problem

Conventional ceramic circuit substrate manufacturing methods face issues with etchant residue accumulation between the metal plate and the ceramic substrate, leading to reduced insulation performance and potential short circuits, while full-surface brazing material coating compromises thermal shock tolerance.

Innovation Solution

A ceramic circuit substrate design featuring a line pattern of brazing material along the edge of the metal plate or circuit pattern section, with a gap within the line pattern to prevent etchant entry and residue formation, combined with a manufacturing method that includes selective etching and nickel plating for enhanced thermal shock tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If brazing material is printed as spots or partial sections, then thermal shock tolerance is improved, but etchant residue accumulates in the gaps causing insulation degradation

Engineering Contradiction:

Improvethermal shock toleranceVSAvoidinsulation performance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The brazing material pattern is segmented into discrete spots arranged in specific configurations (e.g., triangular, rectangular, or circular patterns) rather than continuous coating. This segmentation creates gaps that prevent etchant residue accumulation while maintaining sufficient thermal contact areas for heat dissipation, thus resolving the contradiction between thermal shock tolerance and insulation performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the ceramic substrate are assigned different brazing material patterns: spot patterns in areas requiring thermal management and partial coating sections in areas requiring electrical insulation. This local differentiation allows each region to optimize for its specific function, achieving both thermal shock tolerance and insulation reliability simultaneously.

Inventive Principle:

Principle #3Local quality

2Reliability

If brazing material is coated over the whole surface, then etchant residue is prevented, but thermal shock tolerance deteriorates

Engineering Contradiction:

Improveinsulation performanceVSAvoidthermal shock tolerance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The continuous brazing material coating is segmented into discrete spots arranged in geometric patterns. This segmentation prevents etchant residue accumulation by creating gaps between metal plates and ceramic substrate, while the distributed spot pattern maintains adequate thermal contact for heat dissipation, thus preventing both etchant residue and thermal shock issues.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of complete surface coating, brazing material is applied partially in the form of spots covering only necessary areas for electrical connection and thermal management. This partial action prevents etchant residue accumulation in uncovered gaps while providing sufficient brazing coverage for functional requirements.

Inventive Principle:

Principle #16Partial or excessive action

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

Prevents etchant residue accumulation, maintains insulation integrity, and improves thermal shock tolerance by reducing thermal stress and preventing solder wrap-around during soldering processes.

Implementation Method 1

the pattern of brazing material has a line pattern formed along the edge of the metal plate, and a gap is formed located within the line pattern in between the ceramic substrate and the metal plate

Methodology Applied

Scientific EffectCapillary action blocking: Capillary Action

Implementation Method 2

etch the upper metal plate 4, lower metal plate 5 and the brazing material coated spots 2 by an etchant using the etching resist as a mask

Methodology Applied

Scientific EffectChemical etching:

Implementation Method 3

forming a joint by heating in a furnace at 830° C

Methodology Applied

Scientific EffectBrazing: Brazing

Data Source

PatentUS7776426B2Ceramic circuit substrate and manufacturing method thereof

Publication Date: 2010.08.17 DOWA METALTECH CO LTD

AI summary

A ceramic circuit substrate and a manufacturing method thereof are provided, which has excellent thermal shock tolerance by forming a gap between a circuit pattern section and a ceramic substrate, and has a capability of preventing etchant residue from remaining therein. The ceramic circuit substrate according to the present invention includes patterns of brazing material (8 and 9) formed on the ceramic substrate, and a circuit pattern section jointed to the patterns of brazing material. The patterns of brazing material includes a line pattern along the edge of the circuit pattern. Also, a gap is formed within the line pattern located between the ceramic substrate and the circuit pattern.