High-Temperature Dry Etching Mask for GaN Substrates
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Solution Overview
Problem
Conventional methods for dry etching group-III nitride compound semiconductors at high temperatures suffer from mask pattern collapse due to reflow or decomposition, which affects the quality of the semiconductor substrate.
Innovation Solution
A method involving a patterned mask layer with specific polymer structures, such as those containing units of Formula (1), (2), and (3), or crosslinked structures, is used for dry etching at temperatures between 300° C. and 700° C., preventing mask pattern collapse and maintaining substrate quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dry etching is performed at high temperature (200°C to 600°C) to prevent deterioration of GaN semiconductor quality, then the quality of GaN semiconductor is improved, but the mask pattern collapses due to reflow or decomposition
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and molecular structure of the mask layer material. Specifically, it uses polymers containing aromatic rings (benzene or naphthalene) with specific functional groups (carboxyl, hydroxyl, amino, or ether groups) that exhibit high thermal stability. This structural parameter change enables the mask layer to maintain its shape at etching temperatures of 200°C to 600°C without reflow or decomposition, while still allowing high-quality GaN etching to proceed
Solution Approach 2:
The patent employs composite materials by creating a mask layer from polymer compounds that combine aromatic ring structures with specific functional groups. This composite molecular structure provides both the thermal resistance needed to prevent pattern collapse and the chemical properties required for effective etching processes. The specific combination of aromatic rings (for thermal stability) and functional groups (for chemical reactivity and adhesion) creates a material that simultaneously satisfies both requirements
2Ease of manufacture
If conventional resist materials are used for mask patterns, then the manufacturing process is simple, but the mask pattern collapses at high temperature during etching
Solution Approach 1:
The patent changes the material parameters by replacing conventional resist materials with polymers having specific molecular structures containing aromatic rings and functional groups. This parameter change increases the decomposition temperature and thermal stability of the mask material, enabling it to withstand high-temperature etching processes (200°C to 600°C) without pattern collapse, while maintaining ease of application through standard coating methods
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 enables the formation of patterned group-III nitride compound layers without surface composition changes or crystal defects, facilitating the manufacturing of semiconductor substrates suitable for compound semiconductor devices.
Implementation Method 1
when a patterned mask layer that is formed on a group-III nitride compound layer of a substrate contains a polymer having a specific structure or a crosslinked structure of the polymer, a semiconductor substrate having a patterned group-III nitride compound layer can be manufactured without collapsing a formed mask pattern due to reflow and decomposition during etching the group-III nitride compound layer by dry etching at 300° C. or higher and 700° C. or lower
Implementation Method 2
etching the group-III nitride compound layer by dry etching at 300° C. or higher and 700° C. or lower using the mask pattern
Data Source
AI summary
A method for manufacturing a semiconductor substrate having a patterned group-III nitride compound layer without collapsing a formed mask pattern due to reflow or decomposition even when an etching method at a high temperature of 300° C.-700° C. is used, including the steps: forming a patterned mask layer on the substrate's group-III nitride compound layer, and etching the group-III nitride compound layer by dry etching at 300° C. or higher and 700° C. or lower using the mask pattern, to form patterned group-III nitride compound layer, wherein the patterned mask layer contains a polymer containing a unit structure of the following Formula (1):a polymer containing a unit structure of the following Formula (2):O—Ar1 Formula (2)a polymer containing a structural unit of the following Formula (3):O—Ar2—O—Ar3-T-Ar4 Formula (3)a polymer containing a combination of unit structure of Formula (2) and unit structure of Formula (3), or a crosslinked structure of the polymers.