Aberration Corrector Stepped Electrode Design
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Solution Overview
Problem
In the context of semiconductor manufacturing, existing aberration correctors for multiple electron beam irradiation systems face challenges in accurately correcting astigmatism and distortion aberrations due to the difficulty in manufacturing electrodes with sufficient thickness, which affects the precision of pattern inspection on ultrafine semiconductor patterns.
Innovation Solution
The proposed solution involves an aberration corrector with a lower electrode substrate and an upper electrode substrate, where the upper substrate has passage holes with varying diameters and a shield electrode, allowing for thin electrode thickness while effectively correcting astigmatism and distortion by extending the electric field to the space above the electrodes, thus reducing the influence on adjacent beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of each electrode of a multipole lens is increased to several tens of μm to correct aberration, then the aberration correction precision is improved, but the manufacturing difficulty increases due to narrow pitch between beams
Solution Approach 1:
The invention extends the electric field in the thickness direction (z-direction) by creating a stepped structure in the electrode substrate. The passage hole has a first diameter at the surface and a second larger diameter at a depth of t1, forming a stepped configuration that extends the electric field interaction region without increasing lateral dimensions. This allows adequate aberration correction while maintaining thin electrode thickness suitable for narrow pitch manufacturing
Solution Approach 2:
The electrode substrate is designed with non-uniform structure - the passage hole diameter changes with depth (smaller at surface, larger at depth t1). This local variation in geometry allows the electric field to be concentrated and extended in the thickness direction where needed for aberration correction, while keeping the overall electrode thickness small for manufacturability
2Ease of manufacture
If the electrode thickness is reduced to facilitate manufacturing, then the ease of manufacture is improved, but the aberration correction capability deteriorates
Solution Approach 1:
Instead of increasing lateral electrode thickness, the invention utilizes the depth dimension by creating a stepped passage hole structure. The electric field is extended along the z-axis through the stepped configuration, providing sufficient interaction length for aberration correction while keeping the electrode substrate thin and manufacturable
Solution Approach 2:
The passage hole structure is nested within the electrode substrate with a stepped configuration - a smaller diameter hole at the surface nested within a larger diameter cavity at depth. This nested structure allows the electric field to penetrate deeper into the substrate, extending the correction region without increasing overall thickness
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 configuration enables precise correction of astigmatism and distortion, improving the accuracy of pattern inspection and reducing manufacturing complexity by allowing for thinner electrodes, thereby enhancing the precision of multiple electron beam irradiation systems.
Implementation Method 1
a plurality of electrode sets each being a plurality of electrodes of four poles or more than four poles, which surround a first passage hole of the plurality of first passage holes, for each of the plurality of first passage holes
Implementation Method 2
multipole lenses each of which is for each beam... correcting a trajectory for the purpose of correcting aberration
Implementation Method 3
a shield electrode is disposed on inner walls of the plurality of second passage holes
Implementation Method 4
whose size from a top surface of a body of the upper electrode substrate to a middle of a way to a back side of the upper electrode substrate is a second hole diameter, and whose size from the middle to the back side is a third hole diameter larger than the first hole diameter and larger than the second hole diameter
Data Source
AI summary
Aberration corrector includes a lower electrode substrate to be formed therein with plural first passage holes having a first hole diameter and making multiple electron beams pass therethrough, and to be arranged thereon plural electrode sets each being plural electrodes of four or more poles, surrounding a first passage hole, for each of the plural first passage holes, and an upper electrode substrate above the lower one, to be formed therein with plural second passage holes making multiple electron beams pass therethrough, whose size from the top of the upper electrode substrate to the middle of way to the back side of the upper electrode substrate is a second hole diameter, and whose size from the middle to the back side is a third hole diameter larger than each of the first and second hole diameters, wherein a shield electrode is on inner walls of plural second passage holes.