Electron Beam Drawing Control for Pattern-Density Dose Balancing
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Solution Overview
Problem
In semiconductor manufacturing, drawing devices used for lithography masks and nanoimprint lithography often result in wasteful operations due to inefficient stage speed settings, leading to prolonged overall drawing time, especially for patterns with small irradiation amounts.
Innovation Solution
A drawing device that divides the target drawing region into multiple areas based on pattern density and adjusts the number of irradiations and beam scan speed for each area to ensure the required irradiation amount is achieved, optimizing the use of electron beam irradiation and reducing unnecessary stage movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the stage speed is set to match patterns with large irradiation amounts, then the irradiation accuracy for high-density patterns is improved, but the drawing time increases due to wasteful operations on low-density patterns
Solution Approach 1:
The drawing region is divided into multiple regions based on pattern density (high-density regions and low-density regions). This segmentation allows different stage speeds to be applied to different regions, optimizing both precision and efficiency. The control computer calculates and manages the irradiation amounts separately for each region type.
Solution Approach 2:
Different stage speeds are assigned to different regions based on their specific requirements. High-density patterns receive slower stage speeds for precise irradiation control, while low-density patterns use faster stage speeds to reduce unnecessary operation time. This local optimization resolves the contradiction between overall precision and total drawing time.
2Productivity
If the stage operates continuously at high speed, then the productivity is improved, but the irradiation precision decreases for patterns requiring careful dose control
Solution Approach 1:
The stage speed is made dynamic rather than constant. The control computer adjusts the stage speed based on the pattern density of the current region being drawn. This dynamic adjustment allows the system to achieve both high productivity (through fast speeds in appropriate regions) and high precision (through slower speeds in regions requiring careful dose control).
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 significantly shortens the drawing time by optimizing the irradiation process, ensuring that each area receives the necessary beam exposure while minimizing wasteful operations, thereby improving the overall efficiency of the semiconductor manufacturing process.
Implementation Method 1
a beam generating unit configured to generate a beam of charged particles
Data Source
AI summary
A drawing device includes a device configured to generate a beam of charged particles, a group of optical elements disposed in a path of the beam, the group of optical elements being controlled so that the beam irradiates each of a plurality of divided regions of a target drawing region on which a pattern is to be drawn with the beam, and a control computer configured to divide the target drawing region into the divided regions based on a density of the pattern, and to execute first to n-th irradiations (n is an integer of 2 or more) selectively on the divided regions so that a total irradiation amount of the beam on each of the divided regions reaches a required irradiation amount therefor.