Charged Particle Beam Deflector Evaluation Method
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Solution Overview
Problem
Current methods for evaluating the settling time of a charged particle beam deflector in semiconductor device manufacturing are inaccurate due to measurement variations, making it difficult to determine the optimal settling time for maintaining drawing accuracy without compromising throughput.
Innovation Solution
A method involving the creation and measurement of specific evaluation patterns using a charged particle beam drawing apparatus, where the deflection shift amounts are emphasized by measuring intervals between patterns drawn with varying settling times, allowing for the determination of the optimal settling time by comparing these intervals to a reference value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the settling time is shortened to improve throughput, then productivity increases, but the drawing accuracy deteriorates due to insufficient beam deflection settling
Solution Approach 1:
The invention changes the measurement parameter from direct position measurement to interval measurement between multiple patterns. By measuring the interval between a first pattern and a second pattern drawn at different positions, the method amplifies the deflection shift amount caused by insufficient settling time, making it detectable despite using a short settling time for high throughput
2Ease of operation
If conventional position measurement is used to evaluate deflection shift, then the measurement process is simple, but the measurement precision is insufficient due to inability to separate deflection shift from process variation and measurement error
Solution Approach 1:
The invention segments the measurement into multiple components: drawing a first pattern at a reference position, drawing a second pattern at a different position, and measuring the interval between them. This segmentation allows the deflection shift to be emphasized and separated from other error sources through the interval measurement approach
Solution Approach 2:
The invention transitions from measuring a single position coordinate to measuring the interval (difference) between two positions. This dimensional change from absolute position to relative interval measurement amplifies the deflection shift component and enables more accurate evaluation
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 the accuracy of evaluating deflection shift amounts and allows for the determination of the optimal settling time, enhancing the precision and efficiency of the drawing process.
Implementation Method 1
a method is used in which by using a reduction projection type exposure apparatus, a high-accuracy original pattern (a mask, or in particular, one used by a stepper or a scanner is also referred to as reticle) formed on a quartz is reduced and transferred onto a wafer. The high-accuracy original pattern is drawn by an electron beam drawing apparatus, that is, an electron beam lithography technique is used.
Data Source
AI summary
In one embodiment, a charged particle beam drawing apparatus performs drawing by deflecting a charged particle beam with a deflector. A method for evaluating the apparatus includes making a shot of a first pattern, controlling a deflection amount by the deflector to move an applied position of the beam from the first pattern along a first direction to make a shot of a second pattern, controlling the deflection amount to move the applied position from the second pattern along the first direction to make a shot of a third pattern, controlling the deflection amount to move the applied position from the third pattern along a second direction opposite to the first direction to make a shot of a fourth pattern between the second pattern and the third pattern, calculating an interval between the second pattern and the fourth pattern, and comparing the calculated interval to a reference interval.