Skew-Oriented E-Beam Columns for Wafer Inspection
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Solution Overview
Problem
Conventional electron beam inspection systems for semiconductor manufacturing face inefficiencies due to a mismatch between die spacing and column spacing, leading to complications in scanning and control signal management, especially when the e-beam columns are oriented perpendicularly to the wafer translation direction.
Innovation Solution
The system employs a skew orientation of e-beam columns relative to the wafer translation direction, allowing for a commensurate projected column spacing that matches the die spacing, enabling simultaneous efficient scanning and simplified control signal management across multiple columns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If e-beam columns are oriented perpendicularly to the wafer translation direction, then the scanning coverage is maximized, but the mismatch between die spacing and column spacing complicates control signal management
Solution Approach 1:
The patent applies asymmetry by orienting the row of e-beam columns at a skew angle (non-perpendicular angle) relative to the wafer translation direction. This asymmetric orientation allows the projected column spacing to be commensurate with die spacing, thereby simplifying control signal management while maintaining effective scanning coverage.
2Speed
If e-beam columns are oriented perpendicularly to the wafer translation direction, then the scanning speed is maximized, but the mismatch between die spacing and column spacing reduces inspection efficiency
Solution Approach 1:
The patent uses asymmetric skew orientation of the column row relative to the translation direction to achieve commensurate projected column spacing with die spacing. This enables all columns to align with care areas simultaneously, improving inspection efficiency without sacrificing scanning speed.
Data Source
AI summary
One embodiment described relates to a multiple electron beam apparatus. Multiple columns are arranged in a row configured to generate multiple electron beams. A mechanism is included for translating a substrate so as to be impinged upon by the multiple electron beams. A direction of the substrate translation and a direction of the row of columns are at a skew angle.