Substrate Alignment Optics for Close-Spaced Mark Registration
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Solution Overview
Problem
Existing alignment systems face contamination issues due to measuring devices inserted between substrates, which require substrates to be displaced laterally, leading to inaccuracies and difficulty in achieving precise alignment, especially when alignment marks are close together.
Innovation Solution
A method and device using alignment and positioning optics to detect alignment marks and positioning marks, allowing precise alignment without direct movement of substrates, even when alignment marks are concealed, by utilizing a positioning mark field and additional positioning optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a measuring device is inserted between substrates for alignment measurement, then alignment marks can be measured, but the substrate surface becomes contaminated and substrates must be moved apart by the height of the measuring device
Solution Approach 1:
The patent introduces positioning marks as an intermediary element that enables alignment measurement without direct contact between the measuring device and the substrate surface. The positioning marks are detected by the alignment optic to determine substrate position, while the substrate surfaces remain close together, avoiding contamination from measuring device insertion.
Solution Approach 2:
The patent uses positioning marks as a copy or reference system that replaces the need for direct alignment mark measurement. Instead of measuring alignment marks directly (which requires substrate separation), the system detects positioning marks to calculate alignment, thereby avoiding the harmful effect of inserting measuring devices between substrates.
2Measurement precision
If substrates are moved apart to accommodate a measuring device, then alignment marks can be measured, but lateral displacement occurs during approach invalidating previous alignment
Solution Approach 1:
The patent performs preliminary detection of positioning marks to calculate the required substrate position before actual alignment. By detecting positioning marks and calculating alignment requirements in advance, the system can position substrates accurately without requiring large separations that would cause lateral displacement during approach.
Solution Approach 2:
The patent replaces the mechanical approach of moving substrates apart for measurement with an optical detection system. The alignment optic detects positioning marks optically without requiring physical separation, and calculations determine the precise positioning needed, eliminating lateral displacement issues associated with mechanical substrate movement.
3Object-affected harmful factors
If substrates are positioned very close together (few millimetres or micrometres), then contamination is reduced, but insertion of a measuring device is not permitted
Solution Approach 1:
The patent uses positioning marks as an intermediary that enables measurement functionality without requiring physical measuring devices between substrates. The positioning marks provide reference information that can be detected optically, allowing alignment measurement while maintaining small substrate spacing and avoiding the complexity of inserting measuring devices.
4Ease of operation
If substrate holders are used to position substrates with lateral movement of several millimetres to centimetres, then alignment marks can be accessed, but reproducible positioning in micrometre or nanometre range is very difficult
Solution Approach 1:
The patent uses positioning marks as a reference copy system that enables precise positioning calculations. Instead of relying on mechanical substrate holder precision over large travel distances, the system detects positioning marks and calculates the exact substrate position needed, achieving micrometre or nanometre reproducibility through optical measurement and calculation rather than mechanical positioning.
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
Enables precise alignment of substrates with minimal lateral movement, reducing contamination risks and improving alignment accuracy, especially for closely spaced alignment marks, while extending existing systems without requiring new hardware.
Implementation Method 1
at least one alignment optic for detecting the alignment marks
Implementation Method 2
at least one positioning optic for detecting positioning marks
Data Source
AI summary
A device and a method for the alignment of substrates. The device includes a first substrate holder for receiving a first substrate that has at least two alignment marks, a second substrate holder for receiving a second substrate that has at least two alignment marks, at least one alignment optic for detecting the alignment marks of the first and second substrates, and at least one positioning optic for detecting positioning marks, wherein the alignment marks of the first substrate and the alignment marks of the second substrate can be aligned with one another depending on the positioning marks. The method of alignment includes the steps of fixing the first and second substrates on respective first and second substrate holders, detecting alignment marks on the substrates, detecting positioning marks, and aligning the alignment marks of the substrates with one another in dependence on the positioning marks.