Multi Charged Particle Beam Tracking Control for Semiconductor Writing
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Solution Overview
Problem
In multi-beam writing techniques for semiconductor devices, the settling time required for tracking operations in electron beam writing apparatuses significantly degrades writing speed and throughput due to the need for long stabilization periods in amplifiers, which limits the efficiency of pattern writing on shrinking circuit lines.
Innovation Solution
A method and apparatus that continuously deflect and control multiple charged particle beams to follow stage movement, allowing for reduced settling time by shifting and resetting beam deflection after each writing cycle, thereby maintaining tracking control while minimizing the impact of stabilization periods on overall writing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a low pass filter is built in the amplifier for tracking operation to avoid glitches, then tracking accuracy is improved, but the settling time increases to 10% or more of the maximum irradiation time
Solution Approach 1:
The patent applies preliminary action by performing the tracking operation reset and beam position adjustment before the actual writing operation begins. The system pre-calculates and pre-positions the beams at their starting locations, and the tracking amplifiers are allowed to settle during this preparation phase rather than during the critical writing phase. This ensures that when writing commences, the beams are already in their correct positions and the tracking system is stable, eliminating the need for long settling times during irradiation.
Solution Approach 2:
The patent implements dynamics by continuously adjusting the beam positions and tracking parameters during the writing process. The system dynamically updates the beam deflection angles and positions based on real-time stage movement, allowing the tracking operation to adapt to changing conditions without requiring complete resets. This dynamic adjustment approach maintains tracking accuracy while minimizing interruptions and settling time requirements.
2Measurement precision
If the settling time for tracking operation reset is extended to ensure accuracy, then tracking precision is improved, but the writing speed and throughput are degraded
Solution Approach 1:
The system performs all necessary tracking adjustments and beam positioning operations before the writing process begins. The tracking amplifiers are given sufficient time to settle during the initialization phase, and beam positions are pre-calculated and set. This preliminary preparation ensures that when the actual writing commences, the system is already in a stable, high-precision state, eliminating the need for time-consuming settling periods during the writing process itself.
Solution Approach 2:
The patent maintains continuous tracking operation throughout the writing process without interruption. Once the tracking system is initialized and settled before writing begins, it continues to operate continuously, dynamically adjusting beam positions in real-time as the stage moves. This continuous operation eliminates the need for periodic resets and associated settling times, thereby maintaining both high precision and high writing speed throughout the entire writing process.
3Productivity
If multiple beams are used to increase throughput, then productivity is improved, but the complexity of beam control and tracking increases
Solution Approach 1:
The patent merges the control of multiple beams by using a single set of tracking amplifiers and control electronics to manage all beams simultaneously. Instead of providing separate control systems for each beam, the system uses one amplifier channel to control the deflection of multiple beams in unison. This merging approach maintains the high throughput benefits of multi-beam operation while significantly reducing the complexity of the control system, as the same control signals are applied to all beams through the shared amplifier and deflector system.
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 reduces the writing time and increases throughput by optimizing beam deflection and tracking control, allowing for faster and more precise pattern writing on semiconductor devices with narrower circuit lines.
Implementation Method 1
each unblocked beam is reduced by an optical system and deflected by a deflector so as to irradiate a desired position on a target object
Data Source
AI summary
A multi charged particle beam writing method includes, shifting a writing position of each corresponding beam to a next writing position by performing another beam deflection of multi charged particle beams, in addition to the beam deflection for a tracking control, while continuing the beam deflection for the tracking control after the maximum writing time has passed; emitting the each corresponding beam in the “on” state to the next writing position having been shifted of the each corresponding beam, during a corresponding writing time while continuing the tracking control; and returning a tracking position such that a next tracking start position is a former tracking start position where the tracking control was started, by resetting the beam deflection for the tracking control after emitting the each corresponding beam to the next writing position having been shifted at least once of the each corresponding beam while continuing the tracking control.