Semiconductor Epitaxial Layer Separation Using Multi-Rate Removal Layers
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Solution Overview
Problem
Conventional methods for separating semiconductor epitaxial layers from GaAs substrates often result in the surface of the substrate becoming bonded to the bottom surface of the epitaxial layer, preventing successful separation due to mismatched etching rates and surface interactions.
Innovation Solution
A semiconductor substrate configuration with multiple removal layers of varying etching rates, where a support member with a thinner region is used to prevent bonding by ensuring the epitaxial layer remains separated after etching, utilizing a first removal layer with a lower etching rate than a second removal layer, which is completely etched away, leaving a rough surface to prevent adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single removal layer is used and etching is performed to separate the semiconductor epitaxial layer from the base substrate, then the separation process is simple, but the surface of the base substrate and the bottom surface of the epitaxial layer become very flat and bond to each other, preventing successful separation
Solution Approach 1:
The removal layer is divided into multiple layers with different etching rates (first removal layer with lower etching rate, second removal layer with higher etching rate). This segmentation allows selective removal of the second removal layer while leaving the first removal layer intact, creating a rough surface that prevents bonding and enables successful separation.
Solution Approach 2:
Different regions of the removal layer structure are given different etching rate properties. The first removal layer has a lower etching rate while the second removal layer has a higher etching rate, creating local quality differences that enable selective etching and rough surface formation at specific locations.
2Productivity
If the etching rate of the removal layer is made much higher than that of the base substrate and epitaxial layer, then the removal layer can be selectively removed, but the resulting flat surfaces bond together, preventing separation
Solution Approach 1:
The removal layer is segmented into multiple layers with different etching rates. The second removal layer has a high etching rate for efficient removal, while the first removal layer has a lower etching rate to remain as a rough surface layer that prevents bonding, thus resolving the contradiction between etching efficiency and separation success.
Solution Approach 2:
The etching rate parameter is varied across different layers of the removal structure. By changing the etching rate from low in the first removal layer to high in the second removal layer, the patent achieves both efficient removal and prevention of surface bonding through controlled parameter variation.
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 approach effectively prevents bonding between the semiconductor epitaxial layer and the base substrate, allowing for successful separation and transfer of the epitaxial layer to a destination substrate, facilitating the manufacturing of semiconductor devices with improved yield and surface quality.
Implementation Method 1
the support member being cut off in a region in contact with the removal layer due to application of a force to the semiconductor epitaxial layer
Implementation Method 2
the semiconductor epitaxial layer is separated from the GaAs substrate by removing the removal layer using an etchant such as hydrofluoric acid
Data Source
AI summary
A semiconductor substrate includes: a base substrate; a removal layer, and of which at least a portion is to be removed by performing etching; a semiconductor epitaxial layer provided above the removal layer; and a support member for supporting the semiconductor epitaxial layer in a state where the support member is in contact with side surfaces of the base substrate, the removal layer, and the semiconductor epitaxial layer such that the semiconductor epitaxial layer is positioned above the base substrate, the support member being cut off in a region in contact with the removal layer due to application of a force to the semiconductor epitaxial layer. The thickness of at least a portion of a region of the support member in contact with the removal layer is smaller than the thickness of other regions that are different from the at least the portion of the region in the support member.