Dual-Surface Scribe Lines for Uniform Ceramic-Metal Etching
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Solution Overview
Problem
In the manufacturing of power module boards, the uneven dispersion of Si atoms from brazing material during the joining process leads to differences in Si density between the front and back surfaces of ceramic base material boards, causing uneven etching rates and the generation of braze stains due to varying metal board melting points.
Innovation Solution
Forming scribe lines on both the front and back surfaces of the ceramic base material board allows for the even discharge of melted brazing material, reducing Si density differences and ensuring uniform etching rates across both surfaces, thereby preventing braze stains and achieving consistent metal layer sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If scribe lines are formed only on the front surface of the ceramic base material board, then the manufacturing process is simpler, but the Si density becomes uneven between front and back surfaces causing different etching rates
Solution Approach 1:
The solution segments the scribe line formation process by forming scribe lines on both the front surface and back surface of the ceramic base material board. This segmentation allows the melted brazing material to discharge evenly from both surfaces, preventing uneven Si density distribution that would occur if scribe lines were formed on only one surface.
Solution Approach 2:
The invention applies local quality by forming scribe lines at specific locations on both surfaces of the ceramic board. The scribe lines are strategically positioned to control where the brazing material discharges, ensuring that Si atoms are distributed uniformly throughout the metal boards on both surfaces, thereby achieving consistent etching rates.
2Length of moving object
If the metal board thickness is reduced to achieve thinner ceramic circuit boards, then the overall board thickness is reduced, but the difference in brazing material discharge between front and back surfaces becomes more significant
Solution Approach 1:
By segmenting the scribe line formation to include both front and back surfaces, the invention compensates for the reduced thickness of thin metal boards. The dual-surface approach ensures that brazing material has discharge paths from both sides, maintaining uniform Si density even when the overall board thickness is reduced.
3Strength
If brazing material is used to join metal boards on both surfaces of the ceramic board, then strong joining is achieved, but braze lumps and stains are generated due to uneven brazing material discharge
Solution Approach 1:
The invention extracts the excess brazing material through scribe lines formed on both surfaces of the ceramic board. By providing discharge paths on both the front and back surfaces, the melted brazing material is guided out of the joining assembly in a controlled manner, preventing the formation of braze lumps and stains that would otherwise occur from uncontrolled discharge.
Solution Approach 2:
The invention converts the potentially harmful effect of excess brazing material discharge into a beneficial outcome. By forming scribe lines on both surfaces, the discharge of melted brazing material is controlled and directed, transforming what would be a source of defects (braze stains) into a mechanism for achieving uniform Si density and consistent joining quality.
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 ensures that metal boards on both surfaces of the ceramic base material board are etched at the same rate, reducing the generation of braze stains and achieving uniform metal layer sizes by evenly dispersing the brazing material along multiple scribe lines.
Implementation Method 1
laser light is emitted to a surface (one side) of a ceramic base material board having a large area which can be formed to multiple power module boards to form in advance scribe lines (dividing grooves) dividing the ceramic base material board into a size of the power module boards
Implementation Method 2
the brazing material is melted and spread between the ceramic base material board and the metal boards, and Si atoms in the brazing material are dispersed into the metal boards: as a result, the ceramic base material board and the metal boards are joined
Implementation Method 3
Si atoms in the brazing material are dispersed into the metal boards
Implementation Method 4
the brazing material is melted and spread between the ceramic base material board and the metal boards
Data Source
AI summary
Provided is a method for manufacturing a metal-layer-joined ceramic base material board, in which at least one scribe line is formed, on each of the front and back surfaces of a ceramic base material board, along dividing lines for dividing the ceramic base material board into a plurality of ceramic boards, a metal board covering at least a portion of the dividing lines is joined to each of the front and back surface of the ceramic base material board, the metal boards are etched along the dividing lines to form a plurality of metal layers, and the plurality of metal layers are joined to each of the front and back surfaces of the ceramic base material board.