Two-Step Curing Bottom Anti-Reflection Coating for Overlay Mark Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing single curing step for forming bottom anti-reflection coatings (BARC) in lithography leads to separation issues, resulting in holes around trenches that interfere with accurate overlay error measurement and alignment, limiting the adjustment of lithography process parameters.
Innovation Solution
A two-step curing process is employed for the BARC, where a fluid material is applied and cured at lower temperatures initially for partial crosslinking, followed by a higher temperature step to complete crosslinking and remove solvents, preventing hole formation over overlay marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single curing step is used to form BARC, then the curing process is simple and fast, but holes are formed around trenches interfering with overlay measurement accuracy
Solution Approach 1:
The single curing step is divided into two sequential curing steps. The first curing step performs partial crosslinking at lower temperature, while the second curing step completes the crosslinking and removes solvents at higher temperature. This segmentation prevents hole formation around trenches during the curing process, eliminating interference with overlay measurement accuracy.
Solution Approach 2:
The first curing step performs preliminary partial crosslinking before the second curing step completes the process. This preliminary action allows the BARC material to stabilize and prevent hole formation around trenches before complete curing, thereby preventing measurement interference while maintaining process efficiency.
2Loss of time
If rapid curing is performed in a single step, then the process time is reduced, but the BARC separates from itself forming holes that interfere with measurement
Solution Approach 1:
The rapid single-step curing is segmented into two controlled curing steps with different temperature profiles. The first step at lower temperature performs partial crosslinking gradually, preventing rapid separation and hole formation. The second step completes curing, maintaining structural integrity while keeping total process time efficient.
Solution Approach 2:
The curing temperature parameter is changed between two steps: first curing at a lower temperature for partial crosslinking, then second curing at a higher temperature for complete crosslinking and solvent removal. This parameter change prevents rapid curing-induced separation while maintaining overall process efficiency.
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 ensures accurate overlay measurement and improved alignment by eliminating hole boundaries, allowing for precise adjustment of lithography process parameters and enhanced alignment accuracy.
Implementation Method 1
at least two curing steps are conducted to convert the fluid material into an ARC
Implementation Method 2
a two-step curing process is employed for the BARC, where a fluid material is applied and cured at lower temperatures initially for partial crosslinking, followed by a higher temperature step to complete crosslinking
Implementation Method 3
followed by a higher temperature step to complete crosslinking and remove solvents
Data Source
AI summary
A method for forming an anti-reflection coating (ARC) with no hole over an overlay mark is described, which applies a fluid material of the ARC onto a substrate and then conducts at least two curing steps to convert the fluid material into the ARC. Such a bottom anti-reflection coating with no hole over the overlay mark can improve accuracy of the overlay measurement of lithography, thereby improving the alignment accuracy of the lithography process.