Semiconductor Pattern Transfer Using Shared Alignment Marks
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Solution Overview
Problem
Existing lithography processes face inefficiencies in aligning patterns on semiconductor wafers due to the need for multiple alignment marks, leading to wasted space and inefficient layout design.
Innovation Solution
A pattern forming method that utilizes a pattern forming apparatus with a template and alignment unit to align and transfer patterns efficiently, using a common alignment mark and minimizing the need for additional marks by covering existing marks with additional resist, thereby optimizing the layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple alignment marks are used for pattern alignment, then alignment accuracy is improved, but the area occupied by alignment marks increases and layout efficiency deteriorates
Solution Approach 1:
The patent merges the alignment mark function with the template structure by providing alignment marks directly on the template that will be transferred to the substrate. This eliminates the need for separate alignment marks on the substrate, combining two functions (alignment reference and pattern transfer) into a single integrated system, thereby reducing the total area occupied by alignment features while maintaining alignment accuracy.
Solution Approach 2:
The template serves multiple functions: it acts as both the pattern transfer medium and the alignment reference carrier. The alignment marks on the template serve dual purposes - enabling precise alignment during the imprinting process and simultaneously being transferred as part of the final pattern on the substrate, thus eliminating redundant alignment structures.
2Area of stationary object
If additional resist is applied to cover alignment marks, then the alignment mark function is maintained with fewer marks, but the process complexity increases
Solution Approach 1:
The additional resist is applied in advance during the same coating step as the main resist, before the imprinting process begins. This preliminary application ensures that when the template is pressed onto the substrate, the alignment marks are already covered and will be transferred along with the main pattern, simplifying the overall process by combining multiple coating operations into one.
Solution Approach 2:
The additional resist automatically covers the alignment marks during the normal resist coating process without requiring separate alignment mark protection steps. The system uses the existing resist application mechanism to accomplish the dual task of coating the main area and protecting the alignment marks, thereby reducing process complexity.
3Productivity
If alignment marks are minimized, then layout efficiency is improved, but alignment precision may deteriorate
Solution Approach 1:
The alignment marks are copied from the template to the substrate during the imprinting process. By transferring the alignment marks along with the main pattern using the same template contact, the system ensures that the copied alignment marks maintain the same precision as the original template features, achieving high alignment precision with minimal mark usage.
Data Source
AI summary
According to one embodiment, a pattern forming method includes forming a first resin pattern on a substrate with a first resin. The first resin pattern includes a first transfer pattern and a first mark. A second resin is dispensed to cover the first mark of the first resin pattern. A first pattern is formed including the first transfer pattern and the second resin covering the first mark. The first pattern is then transferred to a first process film on the substrate.