Semiconductor Etchant Composition for Selective Doped-Layer Etching
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Solution Overview
Problem
Current etchant compositions for semiconductor substrates face challenges in selectively and stably etching extrinsic semiconductor substrates with high-concentration doped layers, often resulting in surface damage, contamination, and low etching rates, especially when the doping concentration difference between layers is small, leading to inefficient wafer thinning and potential leakage current issues.
Innovation Solution
An etchant composition comprising a compound represented by Chemical Formula 1, hydrofluoric acid, nitric acid, acetic acid, phosphoric acid, and water, which effectively suppresses bubble formation and provides a high etch selection ratio by including a divalent linking group and specific alkyl and sulfonate substituents, allowing for uniform etching of high-concentration doped layers with reduced concentration differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a wet etching method using conventional etchant composition is used, then the etching process can be performed, but the etching rate is significantly low on silicon substrate with resistivity of about 0.068 Ω·cm
Solution Approach 1:
The patent modifies the chemical composition parameters of the etchant by introducing a specific compound (Formula 1) with defined molecular structure containing carboxylate/sulfonate/sulfate groups and alkyl chains, along with optimized ratios of HF, HNO3, CH3COOH, and H3PO4, to achieve both high etching rate and uniformity on low-resistivity silicon substrates
Solution Approach 2:
The etchant composition is formulated as a composite solution combining multiple acids (hydrofluoric acid, nitric acid, acetic acid, phosphoric acid) with the specific compound (Formula 1), where each component contributes different functions: HF for silicon etching, HNO3 for oxidation, CH3COOH and H3PO4 for buffering and passivation, and Formula 1 compound for enhanced selectivity and uniformity
2Manufacturing precision
If the etching method is used to selectively remove high-concentration doped layer, then the selective etching can be performed, but bubble formation occurs during the etching process
Solution Approach 1:
The compound (Formula 1) acts as an intermediary substance that mediates between the etching agents and the silicon substrate, facilitating controlled etching of high-concentration doped layers while suppressing bubble formation through its specific molecular structure containing divalent linking groups and carboxylate/sulfonate/sulfate moieties that interact with etching byproducts
3Productivity
If the etching process is performed on extrinsic semiconductor substrate, then the wafer thinning can be achieved, but surface damage and contamination occur
Solution Approach 1:
The patent optimizes the chemical parameters of the etchant composition, including the types and concentrations of acids (HF, HNO3, CH3COOH, H3PO4) and the specific compound (Formula 1), to achieve controlled etching that removes material efficiently while minimizing surface damage and contamination through balanced oxidation and passivation reactions
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 etchant composition achieves a high etch selection ratio, minimizes bubble formation, and maintains stable etching properties over time, enabling efficient and reliable etching of extrinsic semiconductor substrates with varying doping concentrations, suitable for semiconductor device manufacturing.
Implementation Method 1
a wet etching method... a wet etchant composition may include a mixed solution of an oxidizing agent, a reducing agent, a buffering agent
Implementation Method 2
a wet etchant composition may include a mixed solution of an oxidizing agent, a reducing agent
Implementation Method 3
a wet etchant composition may include a mixed solution of an oxidizing agent, a reducing agent, a buffering agent, and the like
Data Source
AI summary
Provided is an etchant composition for a semiconductor substrate which may selectively etch a high-concentration doped layer of an extrinsic semiconductor, and according to the present disclosure, an etchant composition for a semiconductor substrate which, in etching an extrinsic semiconductor substrate including doped layers having different doping concentrations, may etch the high-concentration doped layer at a high selection ratio, and suppress bubble formation during an etching process to allow uniform and stable etching, an etching method using the same, and a manufacturing method of a semiconductor substrate may be provided.