Photoresist Smoothing for Semiconductor Pattern Roughness
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Solution Overview
Problem
Current photolithography processes for forming minute patterns in semiconductor devices result in high roughness and variability due to the use of extreme ultraviolet (EUV) light, leading to inconsistent critical dimensions and line edge roughness, which affects the integration and performance of semiconductor devices.
Innovation Solution
A method involving the formation of a hard mask layer, coating and exposing a photoresist film, followed by a smoothing process using organic solvents, and depositing an atomic layer deposition (ALD) layer to create a pattern with reduced roughness, where the ALD layer is anisotropically etched to serve as an etching mask for the hard mask layer, thereby achieving a more precise and smooth pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process using EUV light is used to form minute patterns, then critical dimension can be reduced to tens of nanometers, but line edge roughness and pattern variability increase
Solution Approach 1:
The patent applies preliminary action by performing a smoothing process on the photoresist pattern before using it as an etching mask. The photoresist pattern is treated with organic solvent vapor to reduce surface roughness and line edge roughness before the actual etching process, thereby improving the quality of the final pattern while maintaining the ability to form minute critical dimensions
Solution Approach 2:
The patent uses an organic solvent (such as ethyl lactate, cyclohexanone, or NMP) as an intermediary substance to smooth the photoresist pattern surface. The solvent vapor treats the photoresist pattern to reduce roughness without significantly altering the pattern dimensions, acting as a mediator between the photolithography process and the subsequent etching 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 approach results in a semiconductor device with reduced roughness and improved uniformity, enabling the formation of patterns with critical dimensions as low as 20-50 nm, enhancing the integration and performance of highly integrated semiconductor devices.
Implementation Method 1
A vaporized organic solvent may be sprayed onto the first photoresist pattern
Implementation Method 2
heating the substrate having the first photoresist pattern thereon to a temperature of about 80° C. to about 120° C.
Implementation Method 3
introducing a source gas including silicon onto the substrate to be chemisorbed onto the second photoresist pattern
Implementation Method 4
A reactant including oxygen may be introduced onto the substrate to oxidize the chemisorbed source gas to form the ALD layer including silicon oxide
Implementation Method 5
The ALD layer is anisotropically etched to form an ALD layer pattern on a sidewall of the second photoresist pattern
Implementation Method 6
The photoresist film is exposed and developed to form a first photoresist pattern. A wavelength of light used in the photolithography process may be relatively small. For example, extreme ultraviolet (EUV) light may be used as a light source
Data Source
AI summary
In a method of forming a pattern of a semiconductor device, a hard mask layer is formed on a substrate. A photoresist film is coated on the hard mask layer. The photoresist film is exposed and developed to form a first photoresist pattern. A smoothing process is performed on the first photoresist pattern to form a second photoresist pattern having a roughness property lower from that of the first photoresist pattern. In the smoothing process, a surface of the first photoresist pattern is treated with an organic solvent. An ALD layer is formed on a surface of the second photoresist pattern. The ALD layer is anisotropically etched to form an ALD layer pattern on a sidewall of the second photoresist pattern. The hard mask layer is etched using the second photoresist pattern and the ALD layer pattern as an etching mask to form a hard mask pattern.