Resist Pattern Smoothing via Solvent Vapor and Water Pretreatment
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Solution Overview
Problem
The existing substrate processing methods for semiconductor wafers result in irregular resist patterns due to light wave characteristics, leading to rough surfaces that compromise processing accuracy and prevent the formation of precise circuit patterns, and these methods often require separate devices for ultraviolet-light irradiation and solvent vapor treatment, which can lead to inconsistent processing times and solvent diffusion.
Innovation Solution
A substrate processing method that involves a pretreatment with water molecules, a smoothing process using solvent vapor of a water-soluble solvent like N-methyl-2-pyrolidone, and a posttreatment for drying, which can be enhanced by rotating or heating the substrate to remove solvent and improve chemical resistance, all integrated into a single system to improve processing accuracy and reduce solvent diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate devices are used for ultraviolet-light irradiation and solvent vapor treatment, then processing flexibility is maintained, but processing time increases and solvent diffusion occurs
Solution Approach 1:
The patent combines the ultraviolet-light irradiation device and the solvent vapor treatment device into a single integrated substrate processing system. The housing contains both the UV irradiation unit and the solvent vaporization unit, allowing simultaneous or sequential operation without transferring the substrate between separate devices, thereby reducing processing time and preventing solvent diffusion.
Solution Approach 2:
The integrated system performs multiple functions within a single device: ultraviolet-light irradiation for decomposing protective groups, solvent vapor treatment for smoothing the resist pattern surface, and drying. This multi-functional design eliminates the need for separate dedicated devices while maintaining all required processing capabilities.
2Manufacturing precision
If ultraviolet-light irradiation is performed before smoothing, then the protective group is decomposed enabling smoothing, but processing time increases
Solution Approach 1:
The system enables continuous processing by immediately performing solvent vapor treatment right after ultraviolet-light irradiation within the same chamber, without intermediate steps or substrate transfer. The UV irradiation and solvent vaporization operations are sequentially integrated, maintaining continuous useful action on the substrate to reduce total processing time while achieving the required surface smoothness.
3Manufacturing precision
If solvent vapor is used for smoothing, then surface quality improves, but solvent diffuses into and outside the device
Solution Approach 1:
The patent introduces a reflective plate as an intermediary element that reflects solvent vapor back onto the substrate surface, ensuring uniform solvent distribution while preventing solvent escape. The reflective plate acts as a mediator that redirects the solvent vapor flow, maintaining the smoothing effect while containing the solvent within the processing chamber.
Solution Approach 2:
The system maintains a controlled atmosphere within the housing during solvent vapor treatment, creating an enclosed environment that prevents solvent diffusion outside the device. The housing acts as a containment structure that isolates the solvent vapor to the processing area, protecting the external environment from solvent contamination.
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 method effectively smooths the resist pattern surface, enhances processing accuracy, reduces processing time, and prevents solvent diffusion by uniformly spreading solvent vapor and efficiently removing it, thereby improving the quality of the resist pattern and the chemical resistance of the substrate.
Implementation Method 1
a pretreatment process for coating the surface of the resist pattern with water molecules
Implementation Method 2
a smoothing process for smoothing the surface of the resist pattern by spouting a solvent vapor of a water-soluble solvent capable of dissolving a resist forming the resist pattern on the surface of the resist pattern to swell a surface layer of the resist pattern
Implementation Method 3
a posttreatment process for removing the water molecules and the solvent remaining on the smoothed surface of the resist pattern formed on the substrate by drying
Data Source
AI summary
A solvent vapor is made to adhere efficiently to the surface of a resist pattern without using an ultraviolet irradiation process to improve processing accuracy, to reduce processing time and to suppress the diffusion of the solvent outside a substrate processing system. The surface of a resist pattern R formed on a semiconductor wafer W by an exposure process and a developing process is coated with water molecules m. A solvent vapor of a water-soluble solvent, such as NMP, is spouted on the surface of the resist pattern R coated with the water molecules m. A surface layer of the resist pattern R is swollen by the solvent vapor combined with the water molecules m to achieve a smoothing process. The water molecules m and the solvent s remaining on the resist pattern R on the wafer W after the smoothing process are removed by drying.