Electron Beam Proximity Correction for Uniform Critical Dimensions
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Solution Overview
Problem
Charged particle lithography systems, such as electron beam and ion beam lithography, face challenges in achieving uniformity of critical dimensions (CD) in layout patterns due to scattering effects that cause indirect exposure of neighboring areas, leading to non-uniformity in the resist material.
Innovation Solution
A control system adjusts the amount of energy delivered to the resist material by controlling electron beam intensity, timing, and deflection to maintain the total energy at or slightly above the threshold level, accounting for both direct and indirect exposure to ensure uniform CD across the layout pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electron beam intensity and exposure energy are increased to ensure full exposure of selected locations, then exposure completeness is improved, but neighboring areas become significantly exposed due to scattering
Solution Approach 1:
The patent applies local quality by differentiating exposure treatment between different spatial locations. The system identifies selected locations requiring full exposure versus neighboring areas that should remain unexposed, and adjusts electron beam parameters locally to achieve differential exposure outcomes despite the scattering nature of electron beams
Solution Approach 2:
The patent implements preliminary anti-action by pre-calculating and compensating for scattering effects before exposure. The system determines appropriate exposure parameters in advance that account for the expected scattering distribution, thereby preventing overexposure of neighboring areas while ensuring complete exposure of target locations
2Object-affected harmful factors
If electron beam exposure parameters are adjusted to prevent scattering into neighboring areas, then indirect exposure is reduced, but selected locations may not receive sufficient energy for complete exposure
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting electron beam parameters (intensity, exposure time, beam size) based on location-specific requirements. The system modifies exposure parameters to optimize the balance between delivering sufficient energy to selected locations and minimizing scattering-induced exposure in neighboring areas
Solution Approach 2:
The patent implements preliminary action by pre-determining optimal exposure parameters for each location before actual exposure occurs. The system calculates required energy delivery and expected scattering patterns in advance, allowing precise control of the electron beam to achieve complete exposure of target areas while preventing overexposure of neighboring regions
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 maintains uniform critical dimensions by balancing direct and indirect energy exposure, reducing CD non-uniformity and enhancing the precision of layout patterns in electron beam lithography.
Implementation Method 1
charged particle beams, e.g., electron beams and ion beams, have been used for high resolution lithographic resist exposure
Implementation Method 2
Some of the electrons or ions entering the resist material that is being exposed may be scattered around and into neighboring areas
Data Source
AI summary
A method of generating a layout pattern includes determining a first energy density indirectly exposed to a first feature of one or more features of a layout pattern on an energy-sensitive material when the one or more features of the layout pattern on the energy-sensitive material are directly exposed by a charged particle beam. The method also includes adjusting a second energy density exposed the first feature when the first feature is directly exposed by the charged particle beam. A total energy density of the first feature that comprises a sum of the first energy density from the indirect exposure and the second energy density from the direct exposure is maintained at about a threshold energy level to fully expose the first feature in the energy-sensitive material.