Semiconductor Alignment Mark With Asymmetric Pitch Regions
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Solution Overview
Problem
Current alignment systems in semiconductor manufacturing face challenges in achieving accurate alignment of wafers due to limitations in the design of alignment marks, which affect the precision of circuit pattern transfer during lithography processes.
Innovation Solution
The proposed alignment system employs an alignment mark with symmetrical patterns, featuring regions with different pitch and angle configurations, and utilizes multiple light sources with varying wavelengths to enhance detection accuracy through diffracted light analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional alignment marks with uniform patterns are used, then the alignment process is simple, but the alignment accuracy is insufficient
Solution Approach 1:
The alignment mark is divided into multiple regions (first region, second region, third region, fourth region) with different pitch configurations. Each region contains mark lines with specific pitch values, creating distinct diffracted light signals that enhance measurement precision while maintaining a structured, manageable design
Solution Approach 2:
Different regions of the alignment mark are assigned different local properties (pitch values). The first and third regions have a first pitch, while the second and fourth regions have a second pitch different from the first. This local differentiation creates distinct diffracted light signals that improve alignment accuracy without requiring complete redesign of the entire mark structure
2Measurement precision
If alignment marks with distinct diffracted light signals are designed, then positioning precision is improved, but the detection system complexity increases
Solution Approach 1:
The alignment mark employs asymmetric pitch configurations in different regions, where the first pitch differs from the second pitch. This asymmetry generates distinct diffracted light signals at different angles, enabling precise position detection. The symmetric arrangement of regions (first region symmetric to third region, second region symmetric to fourth region) maintains overall balance while creating detectable asymmetric diffraction patterns
3Manufacturing precision
If symmetrical patterns with different pitches are used, then alignment accuracy is enhanced, but manufacturing complexity increases
Solution Approach 1:
The alignment mark structure serves multiple functions simultaneously: it provides reference patterns for alignment, generates distinct diffracted light signals for precise measurement, and maintains symmetry for ease of fabrication. The multi-functional design allows a single structure to achieve high manufacturing precision without proportionally increasing fabrication complexity
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 improves alignment accuracy by providing distinct diffracted light signals for precise positioning, allowing for reliable and efficient circuit pattern transfer on wafers.
Implementation Method 1
A sensor is used for detecting a first diffracted light diffracted from the alignment mark radiated by the first light
Data Source
AI summary
An alignment system includes a light source for emitting a light. An alignment mark is disposed on a substrate for receiving the light. The alignment mark includes a first pattern and a second pattern disposed on the substrate. The first pattern includes a first region and a second region. The second pattern includes a third region and a fourth region. The first region and the third region are symmetrical with respective to a symmetrical axis. The second region and the fourth region are symmetrical with respective to the symmetrical axis. The first region includes first mark lines parallel to each other. The second region includes second mark lines parallel to each other. A first pitch is disposed between the first mark lines adjacent to each other. A second pitch is disposed between the second mark lines adjacent to each other. The first pitch is different from the second pitch.