Rasterized Pattern Generation with BARC Thickness Compensation
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Solution Overview
Problem
Existing pattern generators face challenges in achieving uniform critical dimension (CD) properties across the surface of radiation-sensitive blanks due to variations in the bottom anti-reflection coating (BARC) thickness, which are not adequately addressed by current methods.
Innovation Solution
A method and device that adapt pattern properties based on the measured thickness variations of the BARC, creating a blank-specific rasterized pattern to compensate for CD variations by integrating BARC thickness measurements into the writing process, using a rasterization module and imaging module to ensure uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard rasterization is used without BARC thickness compensation, then the writing process is simple and fast, but CD uniformity across the substrate deteriorates
Solution Approach 1:
The patent applies preliminary action by measuring the BARC thickness and creating a compensation map before the actual writing process. The rasterization module pre-calculates the adjusted pattern data based on the measured thickness variations, so that when writing occurs, the compensation is already embedded in the pattern data, eliminating the need for real-time adjustments during writing.
Solution Approach 2:
The patent implements local quality by applying different pattern properties to different regions of the substrate based on local BARC thickness variations. The compensation map divides the substrate into regions with different thickness characteristics, and each region receives customized pattern adjustments (such as varying exposure dose or focus) to achieve uniform CD across the entire substrate despite local variations.
2Productivity
If BARC thickness variations are not compensated, then the writing process is faster, but the homogeneity of CD properties across the substrate deteriorates
Solution Approach 1:
The compensation for BARC thickness variations is performed in advance during the rasterization stage rather than during the writing stage. The system measures BARC thickness, generates a compensation map, and adjusts the pattern data beforehand, allowing the actual writing process to proceed at high speed without real-time computational overhead.
Solution Approach 2:
The patent creates a digital compensation map that represents the BARC thickness variations across the substrate. This map is then used to generate an adjusted digital pattern that copies the original design but incorporates compensation values. The writing system simply follows this pre-compensated digital pattern, maintaining high writing speed while achieving CD uniformity.
3Manufacturing precision
If higher quality blanks with uniform BARC are used, then CD uniformity improves, but the cost and availability of suitable blanks deteriorates
Solution Approach 1:
The patent converts the harmful effect of BARC thickness variations into a beneficial outcome by measuring the actual thickness variations and using them to generate compensation data. Instead of discarding substrates with non-uniform BARC, the system characterizes these variations and uses them to create customized compensation maps, thereby turning a defect into a solvable parameter.
Solution Approach 2:
The patent changes the approach from requiring uniform physical BARC thickness to achieving uniform CD through parameter adjustments in the writing process. By varying exposure parameters, focus, or pattern dimensions based on measured BARC thickness, the system achieves consistent CD results on substrates with varying BARC, eliminating the need for uniformly thick BARC layers.
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
Significantly reduces CD variations across the radiation-sensitive blank by adapting print data to match individual BARC thickness profiles, improving CD uniformity and reducing the need for higher quality blanks.
Implementation Method 1
laser as the light source to activate a photoresist of a radiation-sensitive blank
Data Source
Figure 1~2
Figure 3
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AI summary
A method for preparing rasterized patterns for writing of patterns on a radiation-sensitive blank is provided. The radiation-sensitive blank has a bottom anti reflection coating - BARC - covered with a photoresist layer. The said writing method comprises obtaining (S10) of original data representing a pattern to be printed. The original data is rasterized (S30) into the rasterized pattern. Data is obtained (S20) defining a thickness measure of the BARC as a function of lateral position of a radiation-sensitive blank to be patterned. The rasterizing comprises adapting of pattern properties in dependence on the thickness measure of an intended pattern position at the radiation-sensitive blank to be patterned, creating a blank-specific rasterized pattern. A method for writing of patterns on a radiation-sensitive blank is also disclosed, as well as a rasterization module and a pattern generator, utilizing the method for preparing rasterized patterns.