Wafer Alignment Mark with Oblique Intersecting Patterns
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Solution Overview
Problem
As semiconductor manufacturing processes become more complex and finer, existing methods struggle to accurately align multiple layers on a wafer during photolithography, leading to inefficiencies and potential errors in the alignment process.
Innovation Solution
The use of wafer alignment marks, comprising first and second mark patterns, where the second mark patterns are arranged in an oblique direction relative to the first, allows for the irradiation of optical signals to detect coordinates and calculate deviations from a reference position, enabling precise alignment of multiple layers on a semiconductor wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing alignment methods are used for photolithography, then the process is simpler, but the alignment accuracy and efficiency for multiple layers deteriorates
Solution Approach 1:
The alignment mark is divided into multiple distinct patterns including a first mark pattern with line patterns extending in a first direction, and a second mark pattern with line patterns extending in a second direction perpendicular to the first direction. This segmentation allows independent measurement of alignment in different directions, improving overall alignment accuracy while maintaining a structured, manageable configuration
Solution Approach 2:
The invention introduces a second mark pattern with line patterns extending in a second direction (perpendicular to the first direction), adding a dimensional aspect to the alignment measurement. This enables simultaneous measurement of alignment deviations in both the first and second directions, significantly improving alignment precision for multi-layer photolithography without requiring multiple separate measurement systems
2Productivity
If traditional alignment methods are used, then the equipment is simpler, but the alignment time and productivity deteriorates
Solution Approach 1:
The invention combines multiple alignment measurement capabilities into a single integrated alignment mark structure. The first mark pattern and second mark pattern are positioned on the same wafer surface and can be measured simultaneously using a single measurement system, enabling fast multi-directional alignment measurement without requiring sequential measurements or multiple equipment systems
Solution Approach 2:
The alignment mark structure serves multiple functions: it enables measurement of alignment deviations in the first direction using the first mark pattern, measurement of alignment deviations in the second direction using the second mark pattern, and provides reference points for both x-axis and y-axis alignment. This multi-functionality improves productivity by eliminating the need for separate measurement systems for different alignment directions
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 method allows for simultaneous and precise alignment of multiple semiconductor layers, reducing the time required for alignment and improving the accuracy of the photolithography process, thereby enhancing the efficiency of semiconductor chip fabrication.
Implementation Method 1
irradiating an optical signal onto the first mark patterns and the second mark pattern and obtaining coordinates of the second mark pattern by detecting signals from the second mark pattern
Data Source
AI summary
A method for measuring wafer alignment is provided. The method includes providing a plurality of first mark patterns extending in a first direction on a wafer, providing at least one second mark pattern on the first mark patterns such that it overlaps and intersects the first mark patterns, irradiating an optical signal onto the first mark patterns and the second mark pattern and obtaining coordinates of the second mark pattern by detecting signals from the second mark pattern.