Polycrystalline Ceramic Substrate Bonding for Semiconductor Epitaxy
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Solution Overview
Problem
The bonding state of known laminated substrates deteriorates during epitaxial layer formation, leading to decreased production efficiency of semiconductor devices.
Innovation Solution
A polycrystalline ceramic substrate with a specific linear expansion coefficient ratio, between 0.7 and 0.9, is used as a base substrate, bonded to a compound semiconductor substrate with a bonding layer, to maintain the bonding state and suppress efficiency loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a compound semiconductor substrate is used to form an epitaxial layer, then the quality of the epitaxial layer is improved, but the production cost increases
Solution Approach 1:
The patent introduces a polycrystalline ceramic substrate as an intermediary base substrate that mediates between the inexpensive substrate and the compound semiconductor layer. This ceramic substrate has controlled thermal expansion properties that match the compound semiconductor, allowing high-quality epitaxial growth without requiring an expensive compound semiconductor base substrate.
Solution Approach 2:
The patent changes the thermal expansion parameter by selecting and controlling the linear expansion coefficient of the polycrystalline ceramic substrate to be within a specific range (0.5-1.5 times that of the compound semiconductor). This parameter optimization enables compatible thermal matching between dissimilar materials, resolving the contradiction between cost and quality.
2Ease of manufacture
If a relatively inexpensive substrate with different material is used to form an epitaxial layer, then the production cost is reduced, but the quality of the epitaxial layer deteriorates
Solution Approach 1:
The polycrystalline ceramic substrate serves as an intermediary layer between the inexpensive base substrate and the compound semiconductor epitaxial layer. This mediator provides the necessary thermal and mechanical compatibility for high-quality epitaxial growth while allowing the use of cost-effective base materials.
Solution Approach 2:
The patent creates a composite structure consisting of a base substrate, polycrystalline ceramic substrate, and compound semiconductor epitaxial layer. This composite material system combines the advantages of different materials: the cost-effectiveness of the base substrate with the epitaxial quality enabled by the ceramic intermediate layer.
3Manufacturing precision
If a laminated substrate with compound semiconductor base substrate is used, then the epitaxial layer quality is improved, but the bonding state deteriorates during epitaxial layer formation
Solution Approach 1:
The patent optimizes the thermal expansion parameter of the base substrate by selecting polycrystalline ceramic materials with linear expansion coefficients within a specific range (0.5-1.5 times that of the compound semiconductor). This parameter control prevents excessive thermal stress during epitaxial growth, maintaining bonding integrity while enabling high-quality epitaxial layers.
Solution Approach 2:
The patent explicitly addresses thermal expansion mismatch by selecting materials and controlling processing temperatures to accommodate differential thermal expansion between the polycrystalline ceramic substrate and the compound semiconductor. This prevents bonding deterioration during the high-temperature epitaxial formation 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 configuration effectively suppresses the decrease in production efficiency of semiconductor devices by maintaining a stable bonding state during epitaxial layer formation, with a bonding area percentage exceeding 95% in experimental results.
Implementation Method 1
at least one of relational expression (1) and relational expression (2) holds: 0.71/α23/α4 where α1 represents a linear expansion coefficient of the polycrystalline ceramic substrate at 30° C. to 300° C., α2 represents a linear expansion coefficient of the compound semiconductor substrate at 30° C. to 300° C., α3 represents a linear expansion coefficient of the polycrystalline ceramic substrate at 30° C. to 1000° C., and α4 represents a linear expansion coefficient of the compound semiconductor substrate at 30° C. to 1000° C.
Data Source
AI summary
Provided is a polycrystalline ceramic substrate to be bonded to a compound semiconductor substrate with a bonding layer interposed therebetween, wherein at least one of relational expression (1) 0.7<α1/α2<0.9 and relational expression (2) 0.7<α3/α4<0.9 holds, where α1 represents a linear expansion coefficient of the polycrystalline ceramic substrate at 30° C. to 300° C. and α2 represents a linear expansion coefficient of the compound semiconductor substrate at 30° C. to 300° C., and α3 represents a linear expansion coefficient of the polycrystalline ceramic substrate at 30° C. to 1000° C. and α4 represents a linear expansion coefficient of the compound semiconductor substrate at 30° C. to 1000° C.