Dual-Layer Alignment Device Using Static Calibration
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Solution Overview
Problem
Conventional dual-layer alignment systems in semiconductor photolithography are complex and lack accuracy due to independent motion stages and lenses, affecting alignment reliability and precision.
Innovation Solution
A dual-layer alignment apparatus with a fixed frame and a motion stage, where a first measuring device measures the relative positional relationship between a reference mark and a motion-stage mark, and a second measuring device measures the relationship between the reference mark and a fixed-frame mark, allowing the motion stage to be moved to a target location based on derived positional relationships, with a beam splitter enabling simultaneous imaging of optical paths and static calibration for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a movable beam splitter and independent motion stage with lens are used for dual-layer alignment, then alignment functionality is achieved, but system complexity and motion control complexity increase
Solution Approach 1:
The patent combines the beam splitter and motion stage into a single integrated motion stage assembly. The beam splitter is fixed on the motion stage, and both the beam splitter and the lens are carried together by the single motion stage, eliminating the need for independent motion control of separate components. This merging reduces system complexity while maintaining alignment functionality.
Solution Approach 2:
The single motion stage serves multiple functions: it carries both the beam splitter and the lens, and controls their joint movement for both first and second layer alignment operations. This multi-functional design replaces the need for separate motion stages for different alignment tasks, simplifying the overall system structure.
2Measurement precision
If multiple independent motion stages and lenses are used for dual-layer alignment, then alignment coverage is improved, but motion control complexity and system complexity increase
Solution Approach 1:
The patent merges multiple motion control systems into a single motion stage that simultaneously controls the position of the beam splitter and the lens. This single motion control system manages both alignment operations, reducing the complexity associated with coordinating multiple independent motion stages while maintaining the precision required for dual-layer alignment.
3Device complexity
If a simpler quasi-lithography apparatus structure is used without objective lens, then structural simplicity is achieved, but alignment accuracy deteriorates
Solution Approach 1:
The patent introduces a beam splitter as an intermediary optical component that enables the simpler quasi-lithography apparatus to achieve high alignment accuracy. The beam splitter divides and directs light paths to simultaneously image marks from both the first and second layers, compensating for the absence of a high-precision objective lens and enabling accurate dual-layer alignment in a structurally simpler system.
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 solution simplifies the alignment process by making the motion stage the only movable component, enhancing alignment accuracy and reliability, and allows for flexible dual- or multi-lens designs to improve efficiency.
Implementation Method 1
the second measuring device may be a beam splitter allowing the fixed-frame mark and the reference mark to be simultaneously located in two respective fields of view of the beam splitter
Data Source
AI summary
A dual-layer alignment apparatus is disclosed which includes: a fixed frame (40) and, disposed thereon, a first measuring device (50) and a mark plate (41), the mark plate (41) having a fixed-frame mark (20); and a motion stage (60) and, disposed thereon, a reference mark (30), a motion-stage mark (70) and a second measuring device (10). The first measuring device (50) is configured to measure a relative positional relationship between the reference mark (30) and the motion-stage mark (70), the second measuring device (10) is configured to measure a relative positional relationship between the reference mark (30) and the fixed-frame mark (20), from which a final relative positional relationship between the motion-stage mark (70) and the fixed-frame mark (20) is derived, based on which the motion stage (60) is displaced to a target location. A corresponding dual-layer alignment method is also disclosed. In the apparatus, the motion stage (60) is the only movable component. Additionally, coordinate relationships can be calibrated in a static manner in order to immunize calibration accuracy from positioning accuracy of the motion stage (60), such that the alignment accuracy is improved. Further, a dual- or multi-lens design can be employed to allow additional improvements in flexibility and alignment efficiency.