Printed Optical Routing for Parallel Alignment Mark Imaging
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Solution Overview
Problem
Existing lithographic technologies face challenges in measuring multiple alignment marks in parallel due to geometric arrangement issues, limiting the efficiency and accuracy of overlay error detection in lithographic processes.
Innovation Solution
A metrology system with a replaceable optical routing component that includes a plurality of optical routing elements, allowing for parallel imaging of multiple target alignment marks by configuring the substrate to be positioned under and away from the component, which can include waveguides or optical couplers, and active or passive integrated photonic elements to guide and detect light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single sensor is used to measure alignment marks sequentially, then the device complexity is low, but the measurement time increases and productivity decreases
Solution Approach 1:
The optical detection system is segmented into multiple independent optical paths, each dedicated to detecting a specific alignment mark. This allows parallel measurement of multiple marks simultaneously, increasing productivity without requiring a single complex sensor system.
Solution Approach 2:
The patent transitions from sequential measurement (single dimension of time) to parallel measurement by adding spatial dimension - multiple optical paths arranged in different spatial directions to simultaneously detect multiple alignment marks.
2Productivity
If multiple sensors are arranged in parallel to detect multiple alignment marks simultaneously, then productivity increases, but the geometric arrangement becomes complex and difficult to optimize
Solution Approach 1:
A single optical sensor is designed to perform multiple functions by receiving light from different optical paths that converge on it. The sensor detects signals from multiple alignment marks simultaneously through different optical routes, eliminating the need for multiple separate sensors and their complex geometric arrangements.
Solution Approach 2:
Optical elements (mirrors, beam splitters, waveguides) serve as intermediaries to redirect and route light from multiple alignment marks to a single sensor. These intermediaries simplify the overall system architecture by mediating between the multiple detection targets and the single sensor.
3Measurement precision
If alignment marks are measured sequentially one by one, then the geometric arrangement is simple, but the overlay error detection accuracy decreases due to repeated positioning
Solution Approach 1:
The optical system is designed so that light from multiple alignment marks can be detected simultaneously and continuously. This continuous parallel detection eliminates repeated positioning operations and maintains measurement precision by avoiding the time-dependent variations that occur in sequential measurement.
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 simultaneous imaging of multiple alignment marks, improving the efficiency and accuracy of overlay error detection in lithographic processes by optimizing the geometric arrangement of sensors.
Implementation Method 1
a replaceable optical routing component that includes a plurality of optical routing elements... configured to guide light to or from the plurality of optical routing elements
Implementation Method 2
a second end of each of the plurality of optical routing elements is optically coupled to the detection module
Data Source
AI summary
Disclosed herein are embodiments that relate to a metrology apparatus and associated methods for imaging a plurality of targets (e.g., alignment marks) disposed on of a substrate (550, 650) in parallel using a fixed sensor (510, 530, 610) component that provides electrical, optical, and mechanical connections in combination with a swappable optical routing component (520, 620, 720). The swappable optical routing component (520, 620, 720) allows for target alignment marks to be placed in a field in any desirable configuration.