Adaptive Drift Diagnosis for Charged-Particle Beam Drawing
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Solution Overview
Problem
The challenge in electron beam drawing for semiconductor manufacturing is the degradation of pattern drawing accuracy due to beam drift caused by charge-up and undesired electric fields, which requires frequent drift diagnosis and correction, but shortening the diagnosis time interval worsens throughput and increases manufacturing costs.
Innovation Solution
A charged-particle beam drawing method that stores multiple time interval patterns for drift diagnosis, selects specific patterns based on event types and regions, and performs intermittent drift corrections to optimize diagnosis intervals, ensuring high accuracy and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If drift diagnosis is performed frequently to maintain drawing accuracy, then manufacturing precision is improved, but productivity deteriorates due to increased interruption time
Solution Approach 1:
The patent applies dynamics by making the drift diagnosis interval adaptive rather than fixed. The control unit dynamically adjusts the time interval between drift diagnoses based on the actual drift amount measured in previous intervals. When drift is small, the interval is extended to maintain throughput; when drift exceeds a threshold, the interval is shortened to maintain precision. This dynamic adjustment resolves the contradiction between frequent diagnosis (for precision) and reduced interruptions (for productivity).
Solution Approach 2:
The patent changes the parameter of diagnosis interval based on measured drift conditions. Instead of using a constant time interval, the system modifies the interval parameter in response to varying drift amounts. This parameter change allows the system to optimize both precision and productivity by adapting the diagnosis frequency to actual beam stability conditions.
2Manufacturing precision
If drift diagnosis interval is shortened to maintain accuracy, then manufacturing precision is improved, but loss of time increases due to more frequent interruptions
Solution Approach 1:
The system dynamically adjusts the diagnosis interval based on actual drift conditions rather than using a fixed short interval. When the beam is stable (small drift), the interval is extended to minimize time loss. When drift increases beyond acceptable levels, the interval is shortened to maintain precision. This dynamic approach reduces overall time loss while maintaining required accuracy.
Solution Approach 2:
The patent implements feedback by measuring the drift amount in each interval and using this information to determine the next diagnosis interval. The control unit receives feedback on beam position stability and adjusts the timing of subsequent diagnoses accordingly. This feedback mechanism ensures accuracy is maintained only when necessary, reducing unnecessary interruptions and time loss.
3Manufacturing precision
If drift correction is performed frequently to maintain beam position accuracy, then manufacturing precision is improved, but productivity deteriorates due to reduced drawing time
Solution Approach 1:
The frequency of drift correction is made dynamic based on measured drift amounts. Corrections are performed frequently only when drift exceeds thresholds, rather than at fixed frequent intervals. This dynamic correction strategy maintains beam position accuracy when needed while maximizing effective drawing time when the beam is stable, resolving the contradiction between precision and productivity.
Solution Approach 2:
The correction frequency parameter is changed based on drift conditions. The system transitions from fixed-frequency correction to variable-frequency correction where the parameter adjusts according to actual beam stability. This allows the system to maintain precision requirements while minimizing interruptions to the drawing process, thereby preserving productivity.
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 allows for optimized drift diagnosis intervals tailored to each drawing region and event, achieving both high drawing accuracy and high throughput while minimizing manufacturing costs.
Implementation Method 1
a pattern is drawn on a sample placed on a movable stage by electron beam which is formed by passing through openings of first and second formation apertures
Implementation Method 2
deflection-controlled by a polarizer
Implementation Method 3
a charge-up is generated and a undesired electric field is generated accordingly. In this case, the trajectory of the electron beam irradiated with deflection toward the mask is changed
Data Source
AI summary
A charged-particle beam drawing method includes: storing a plurality of time interval patterns defining time intervals for performing a diagnosis of a drift amount of charged-particle beam; drawing a predetermined drawing pattern on a sample by irradiating the beam on the sample; receiving first event information including occurrence of event and type of event; acquiring region information specifying a region being drawn by the beam; selecting a specific time interval pattern from the plurality of time interval patterns based on the type of the event of the first event information and the region information; diagnosing the drift amount of the beam based on the specific time interval pattern, until second event information is received, the second event information includes occurrence of event and type of event; and drawing a predetermined drawing pattern on the sample while performing a drift correction of the charged-particle beam, based on the diagnosing.