Grating Mark Measurement Device for Lithography Alignment
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Solution Overview
Problem
Conventional lithography exposure apparatuses face challenges in achieving a wide field of view for grating mark detection without increasing the size of the objective optical system, which is necessary for precise alignment in semiconductor and liquid crystal display device manufacturing.
Innovation Solution
A measurement device with an irradiation system, objective optical system, and beam receiving system that scans a measurement beam across a grating mark on an object, using an objective optical element to deflect or diffract the diffraction beam towards the beam receiving system, allowing for precise positional information retrieval and control of the object's position for pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the field of view of the objective lens is widened to enable scanning measurement beam detection, then the detection capability is improved, but the size of the objective optical system increases
Solution Approach 1:
The patent segments the optical system into two functional parts: a compact objective optical system for focusing the measurement beam, and a separate scanning mechanism (galvano mirror or oscillating mirror) that directs the beam across the grating mark. This segmentation allows the objective lens to maintain a narrow field of view while the scanning mechanism provides the wide detection coverage, resolving the contradiction between field of view and system size.
Solution Approach 2:
The patent introduces an intermediary scanning element (galvano mirror or oscillating mirror) that mediates between the compact objective optical system and the grating mark detection. This intermediary redirects the measurement beam across the grating mark without requiring the objective lens itself to have a wide field of view, thus maintaining compact system size while achieving wide detection capability.
2Measurement precision
If a scanning measurement beam is used for grating mark detection, then positional information accuracy is improved, but an objective optical system with wide field of view is required which increases system size
Solution Approach 1:
The patent separates the measurement function into two independent components: a compact objective optical system that provides precise focusing, and a scanning mechanism that provides wide-area coverage. This segmentation enables high measurement precision through the focused beam while keeping the overall system size compact by eliminating the need for a large-field objective lens.
Solution Approach 2:
The patent replaces the conventional approach of using a large-field objective lens with a mechanical scanning system (galvano mirror or oscillating mirror). This substitution allows the use of a compact objective optical system while achieving wide detection coverage through the scanning mechanism, thus maintaining measurement precision without increasing system size.
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 enables precise alignment and pattern formation on semiconductor and liquid crystal display devices by maintaining a compact objective optical system while achieving a wide field of view, improving manufacturing efficiency and accuracy.
Implementation Method 1
the objective optical element deflects or diffracts the diffraction beam generated at the grating mark toward the beam receiving system
Data Source
AI summary
A measurement system in which an object that moves toward a processing position serves as a measurement target. In the processing position a processing device is capable of applying processing to the object. The measurement system includes: a mark detection device that has an irradiation system to irradiate a mark provided at the object that is moving with a measurement beam while moving the measurement beam; and a beam receiving system to receive a beam from the mark. The irradiation system irradiates the object with the measurement beam while moving the measurement beam, during a period when the object moves toward the processing position.