Multi-Beam Mark Position Measurement for Precise Pattern Alignment
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Solution Overview
Problem
Existing multi-beam writing methods face challenges in accurately measuring the position of marks due to deflection distortion and beam drift, which affects the precision of pattern alignment and drift correction in semiconductor devices.
Innovation Solution
A method and apparatus that utilize a multi-beam system with controlled beam ON regions to scan marks pseudo-fashion, detecting reflected charged particle signals to calculate and adjust irradiation positions accurately, incorporating a controller and mark position calculator to enhance precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple beams are used to scan a wide range for mark position measurement, then the measurement coverage is improved, but deflection distortion occurs and beam drift is generated reducing measurement accuracy
Solution Approach 1:
The multi-beam is divided into multiple independent beam groups that can be selectively activated. Instead of using all beams simultaneously across a wide area, the patent segments the beams and activates only the necessary groups for each measurement phase, reducing deflection distortion while maintaining adequate measurement coverage
Solution Approach 2:
The patent dynamically adjusts which beams are activated (ON/OFF) based on the measurement requirements. The beam activation pattern changes dynamically during the measurement process to optimize between coverage area and measurement precision, avoiding the static approach of using all beams throughout
2Measurement precision
If the on-beam region is sequentially shifted to measure different beam positions, then the measurement precision is improved, but the measurement time increases
Solution Approach 1:
The patent applies partial action by activating only the necessary subset of beams for each measurement phase rather than using all beams continuously. This selective activation reduces the total measurement time while maintaining precision by focusing resources on the critical measurement areas
Solution Approach 2:
The beam activation follows a periodic pattern where different beam groups are activated in sequence. This structured periodic activation allows systematic measurement of different beam positions while optimizing the timing to minimize total measurement duration
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 high-accuracy measurement of mark positions, reducing deflection distortion and beam drift, thereby improving pattern alignment and reducing mask loss in semiconductor manufacturing.
Implementation Method 1
detecting a reflected charged particle signal from the mark
Implementation Method 2
when a multi-beam is deflected by a deflector to perform scanning
Data Source
AI summary
The mark position is measured with a multi-beam with high accuracy. A multi charged particle beam writing method includes forming a multi-beam in which charged particle beams are arranged with a predetermined pitch, irradiating a mark with beams in an on-beam region while shifting irradiation positions of the charged particle beams by sequentially changing the on-beam region in which beams in a partial region of the multi-beam are set to ON, the mark being provided at a predetermined position and having a width greater than the predetermined pitch, detecting a reflected charged particle signal from the mark, and calculating a position of the mark, and adjusting the irradiation positions of the multi-beam based on the calculated position of the mark, and writing a pattern.