Substrate Alignment via Fixed Mark and Stored Coordinates
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Solution Overview
Problem
Current semiconductor processing techniques face challenges in achieving precise alignment of substrates during consecutive production steps, particularly at the nanometer scale, due to limitations in optical alignment systems and the need for sequential alignment processes, which decreases efficiency and increases processing time.
Innovation Solution
A method involving a substrate with a fixed alignment mark and stored position information allows for high-precision alignment by redetermining the alignment mark's position during processing, enabling separate measurement and processing steps, and using a substrate support with integrated alignment marks for stable and efficient substrate handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical alignment methods are used for substrate alignment during processing steps, then alignment can be performed with current technology, but the precision is insufficient for nanometer-scale structures
Solution Approach 1:
The patent replaces optical alignment methods with a mechanical coordinate system approach. A physical coordinate system is affixed to the substrate holder, and processing positions are determined through mechanical coordinate determination rather than optical detection. This substitution enables nanometer-scale precision by using mechanical reference markers and coordinate transformations instead of optical methods, directly resolving the insufficiency of optical alignment for nanometer-scale structures.
2Measurement precision
If sequential alignment steps are performed for each process area, then alignment accuracy can be maintained, but processing time increases and efficiency decreases
Solution Approach 1:
The patent implements preliminary coordinate determination for all process areas before processing begins. The coordinate system is established once on the substrate holder, and all processing positions are pre-calculated using coordinate transformations. This eliminates the need for repeated sequential alignment steps during processing, maintaining nanometer-scale accuracy while significantly reducing processing time and improving throughput.
Solution Approach 2:
The patent uses a reference coordinate system that is copied or transferred from the substrate holder to the processing apparatus. By creating a coordinate mapping between the substrate reference frame and the processing tool reference frame, the system can rapidly determine processing positions without performing full alignment procedures for each step, thereby maintaining precision while enhancing efficiency.
3Reliability
If alignment marks are transferred or refreshed after each production step, then alignment reference can be maintained, but errors accumulate and manufacturing efficiency decreases
Solution Approach 1:
The patent extracts the alignment reference function from the substrate surface marks and relocates it to a fixed coordinate system on the substrate holder. By separating the reference frame from the substrate itself and anchoring it to the holder, the system eliminates the need to transfer or refresh marks after each step. This prevents error accumulation while maintaining reliable alignment reference throughout the entire production process.
Data Source
AI summary
A substrate can efficiently be manufactured by separating the alignment and the actual processing when an alignment mark is provided, which is fixed with respect to the substrate and when position information on a position of a process area on the substrate is retrieved with respect to the alignment mark before the substrate is processed. During the processing alignment can then be performed by redetermining the position of the alignment mark only once and by using the stored position information on the position of the process area.