Photo-cured Layer Homogeneity via Dual Composition Compensation
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Solution Overview
Problem
During imprint and nanoimprint lithography processes, uneven evaporation of polymerizable monomers with high vapor pressure leads to non-uniform resist layers, causing composition changes and etch rate variations, which affect the homogeneity of photo-cured resist layers.
Innovation Solution
A method involving the application of two photocurable compositions with different weight percent ratios of the same monomers, where the second composition compensates for the evaporation of the first, forming a combined layer with a uniform monomer distribution, ensuring a homogeneous photo-cured layer with minimal etch rate and carbon content variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single photocurable composition is applied, then the process is simple, but the monomer evaporation causes non-uniform composition and etch rate variations
Solution Approach 1:
The single photocurable composition is divided into two separate compositions, each containing the same monomers but in different weight percent ratios. This segmentation allows the first composition to be applied uniformly across the substrate, while the second composition compensates for evaporation losses in specific regions, thereby maintaining composition uniformity without overly complicating the manufacturing process.
Solution Approach 2:
The second photocurable composition is applied selectively to specific regions of the substrate where evaporation losses are anticipated or detected. By adjusting the local composition in these regions, the method compensates for non-uniform evaporation and maintains homogeneous material properties across the entire wafer, including etch rate and carbon content.
2Strength
If the first photocurable composition uses a high vapor pressure monomer, then the composition is reactive and cures well, but the monomer evaporates unevenly causing composition changes
Solution Approach 1:
The method changes the concentration parameter of monomers with different vapor pressures in different regions of the photocurable composition. The first composition contains monomers in a standard ratio, while the second composition adjusts the ratios to compensate for evaporation. This parameter change allows the high vapor pressure monomer to maintain its reactive properties while preventing composition instability through regional adjustment.
Solution Approach 2:
The second photocurable composition is applied in advance to compensate for the evaporation that will occur during the imprinting and curing process. By pre-calculating and applying the compensation composition before the actual imaging and curing steps, the method prevents composition changes rather than correcting them afterward, maintaining both reactivity and compositional stability.
3Manufacturing precision
If compensatory measures are taken for evaporation, then composition uniformity is improved, but the process complexity increases
Solution Approach 1:
The compensation for evaporation is performed as a preliminary action by applying the second photocurable composition before the actual imprinting and curing process. The amount and location of the second composition are pre-calculated based on expected evaporation patterns, allowing the compensation to be built into the resist structure before imaging begins. This approach maintains manufacturing precision while limiting process complexity by performing the compensation in advance rather than requiring complex real-time control.
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 method achieves a photo-cured layer with etch rate variations not greater than 5% and carbon content variations not greater than 2%, resulting in a highly homogeneous material structure throughout the layer.
Implementation Method 1
photo-curing the combined liquid layer to form the photo-cured layer
Implementation Method 2
the monomer with the highest vapor pressure of a resist composition may evaporate at a greater rate than the other components of the resist
Implementation Method 3
a ratio of a vapor pressure of the first monomer to a vapor pressure of the second monomer is at least 3
Data Source
AI summary
A method of forming a photo-cured layer on a substrate can comprise using a first photocurable composition and a second photocurable composition, wherein both photocurable compositions may contain the same types of polymerizable monomers but in different concentration ratios. The concentration ratios of the monomers in each of the two photocurable compositions can be adapted that the uneven loss of one type of monomer from the first photocurable composition due to unwanted evaporation in certain regions of the substrate may be compensated by the second photocurable composition, which contains a higher amount of said monomer. The two photocurable compositions can further be adapted to easily merge to a combined layer with a very even distribution of the polymerizable monomers. This may allow forming photo-cured layers having an excellent homogeneous material structure throughout the layer.