Ceramic Substrate Cavity Control via Sand Blasting
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Solution Overview
Problem
The high fabrication cost and precision issues in ceramic package substrates due to material shrinkage and the need for mold modification during the sintering process, which affects the size and shape of cavities in chip receiving areas.
Innovation Solution
A method involving a preformed trench, a patterned protective layer, and a sand blasting process to precisely control the size and shape of cavities in ceramic substrates, allowing for the use of a common base substrate without mold modification, and enabling the fabrication of ceramic substrates with varying cavity shapes and sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common mold is used for fabricating ceramic package substrates, then the fabrication cost is reduced, but the size and shape of cavities cannot be precisely controlled due to material shrinkage during sintering
Solution Approach 1:
The patent applies preliminary action by forming a preformed trench in the green ceramic compact before sintering. This trench serves as a precise template that guides the subsequent sand blasting process, ensuring that the final cavity dimensions are determined by the trench geometry rather than being affected by sintering shrinkage. The protective layer is also applied in advance to mask areas that should not be eroded, further ensuring precision.
Solution Approach 2:
The patent replaces the traditional mold-based mechanical system with a chemical/physical erosion system. Instead of relying on a mold to define cavity shapes (which requires expensive mold modifications for each design change), the invention uses sand blasting to erode the ceramic material according to a preformed trench pattern. This substitution allows precise cavity formation without requiring precise mold fabrication.
2Adaptability or versatility
If the mold is modified or redesigned to vary the carrying area or side wall of ceramic package substrate, then different product specifications can be achieved, but the fabrication cost increases significantly
Solution Approach 1:
The patent uses preliminary action by creating a preformed trench that defines the desired cavity geometry before sintering. This trench can be easily modified for different product specifications without changing the mold itself. The protective layer is also selectively applied to achieve different side wall configurations, allowing product variation while maintaining the same base mold.
Solution Approach 2:
The patent applies parameter changes by controlling the sand blasting process parameters (such as blasting time, sand particle size, and blasting pressure) to achieve different cavity dimensions and shapes. By changing these process parameters rather than modifying the mold, the invention can produce various product specifications at low cost.
3Device complexity
If material shrinkage during sintering is accepted, then the sintering process is simpler, but the cavity size and shape are affected and cannot be precisely controlled
Solution Approach 1:
The patent applies preliminary anti-action by forming a preformed trench that compensates for the expected material shrinkage during sintering. The trench dimensions are designed to account for the shrinkage that will occur, so that after sintering and sand blasting, the final cavity achieves the desired precise dimensions. This preliminary compensation counteracts the harmful effect of shrinkage.
Solution Approach 2:
The patent replaces the reliance on mold precision (which would need to account for shrinkage) with a post-sintering sand blasting process guided by a preformed trench. This substitution allows the sintering process to proceed with standard complexity while achieving high precision in the final cavity dimensions through the trench-guided erosion process.
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 method reduces fabrication costs and increases the precision of cavity shapes and sizes, allowing for efficient packaging of semiconductor chips without abandoning defective products, thus promoting yield and precision.
Implementation Method 1
sand-blasting the second surface (142) of the ceramic substrate (14) to form a cavity (144)
Data Source
AI summary
A method for manufacturing a ceramic substrate is characterized in using a preformed trench, a patterned protective layer and a sand blasting process to manufacture a cavity in a ceramic substrate and control the cavity size and shape of the ceramic substrate. The ceramic substrate is collocated with a base substrate to form a package substrate for packaging a semiconductor chip. The manufacturing method set forth above can lower the manufacturing cost and raise the accuracy of the size and shape of the cavity of the ceramic substrate. The abovementioned method can reduce the fabrication cost and increase the precision of the shape and size of a ceramic substrate.