Electron Beam Apparatus Charge Correction Circuitry
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Solution Overview
Problem
Current electron beam lithography techniques face challenges in achieving high precision due to positional displacement caused by charging effects, particularly when using chemically amplified resists, which are not compatible with traditional charge dissipation layers, and existing correction methods provide insufficient accuracy for modern micropatterning demands.
Innovation Solution
An electron beam apparatus and method that utilize charge amount distribution processing circuitry combining exponential and proportional functions to correct positional displacement, allowing for precise irradiation positioning without the need for charge dissipation layers, using a neural network model to optimize dose distribution and pattern area density for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge dissipation layer is formed on the substrate to correct beam irradiation positional displacement, then the charging effect is reduced, but the substrate becomes incompatible with chemically amplified resist and fabrication cost increases
Solution Approach 1:
The patent introduces a charge dissipation coating as an intermediary layer that is compatible with chemically amplified resist. This coating serves as a mediator between the substrate and the resist, providing charge dissipation functionality without interfering with the resist's chemical amplification process. The coating has specific properties (acid resistance, charge dissipation capability) that allow it to fulfill its function while being compatible with the resist system.
Solution Approach 2:
The patent changes the parameters of the charge dissipation layer by forming a coating with specific compositional and functional properties. Instead of using a traditional charge dissipation layer with acid properties, the patent creates a coating with controlled acid resistance and charge dissipation characteristics. This parameter change allows the layer to be compatible with chemically amplified resist while maintaining its charge dissipation function.
2Reliability
If conventional charge correction methods are used, then some charging effects are addressed, but positional displacement accuracy is insufficient for modern micropatterning demands
Solution Approach 1:
The patent implements a feedback mechanism where the actual beam irradiation position is measured and compared with the intended position. Based on this feedback, the system calculates the positional displacement caused by charging effects and adjusts the beam irradiation position accordingly. This closed-loop feedback system continuously corrects positional errors, achieving high precision suitable for modern micropatterning.
Solution Approach 2:
The patent performs preliminary calculation of the charge amount distribution before beam irradiation. By predicting the charging effects in advance and pre-correcting the beam irradiation position, the system prevents positional displacement rather than merely compensating for it after the fact. This preliminary action enables high precision pattern formation.
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
The solution effectively corrects positional displacements with high precision, enabling accurate pattern formation on semiconductor devices by using a combination of exponential and proportional functions to manage charge distribution and dose modulation, enhancing the accuracy of electron beam lithography beyond existing methods.
Implementation Method 1
When a substrate such as a mask is irradiated with an electron beam, the irradiation position and surroundings thereof are charged by an electron beam irradiated in the past
Implementation Method 2
an electron beam column including an emission source that emits the electron beam and a deflector that deflects the electron beam to irradiate a corrected irradiation position with the electron beam
Data Source
AI summary
According to one aspect of the present invention, an electron beam apparatus includes charge amount distribution operation processing circuitry that operates a charge amount distribution of an irradiation region in a case that a substrate is irradiated with an electron beam using a combined function combining a first exponential function having an inflection point and at least one of a first-order proportional function and a second exponential function that converges and depending on a pattern area density; positional displacement operation processing circuitry that operates a positional displacement of an irradiation pattern formed due to irradiation of the electron beam using the charge amount distribution obtained; correction processing circuitry that corrects an irradiation position using the positional displacement; and an electron beam column including an emission source that emits the electron beam and a deflector that deflects the electron beam to irradiate a corrected irradiation position with the electron beam.