Semiconductor Pattern Measurement Layout to Prevent SEM Burn
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Solution Overview
Problem
Existing semiconductor pattern measurement methods using electron beams often result in damage to the measurement region due to overlapping electron beams, leading to issues like SEM burn and the exclusion of important patterns from measurement, along with inefficient calculation of separation distances.
Innovation Solution
A method involving the extraction of patterns from a full-chip database, assigning IDs, forming a two-dimensional grid structure, sorting patterns by frequency, and measuring only those assigned to grids with sufficient separation distances, thereby reducing overlap and optimizing pattern measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high voltage electron beams are emitted to measure patterns, then measurement precision is improved, but the measurement region is damaged due to overlapping electron beams
Solution Approach 1:
The patent segments the measurement process by dividing patterns into different types (first type and second type) and applying different measurement strategies to each. High-voltage electron beams are used for first type patterns where precision is critical, while low-voltage or alternative methods are used for second type patterns to avoid damage, thus resolving the contradiction between measurement precision and damage prevention
Solution Approach 2:
The patent applies local quality by using different electron beam conditions (high voltage vs. low voltage) for different pattern types based on their specific measurement requirements. This allows high precision measurement where needed while preventing damage in sensitive regions, addressing the contradiction between measurement quality and damage avoidance
2Reliability
If all patterns are measured using high voltage electron beams, then measurement completeness is improved, but computational efficiency deteriorates due to overlapping beams and redundant measurements
Solution Approach 1:
The patent applies partial action by measuring only the necessary patterns with high-voltage electron beams (first type patterns) while using alternative methods for other patterns (second type). This ensures measurement completeness for critical patterns while improving computational efficiency by avoiding redundant high-voltage measurements on all patterns
Solution Approach 2:
The patent changes the measurement parameters (electron beam voltage, measurement method) based on pattern type. By categorizing patterns and applying different parameter sets, the system achieves measurement completeness for required patterns while significantly improving computational efficiency through optimized resource allocation
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
Prevents or reduces metrology damage, ensures all required patterns are measured while maintaining sufficient separation distances, and optimizes computational efficiency by minimizing duplicate measurements and resource consumption.
Implementation Method 1
a measurement region has often been damaged because high voltage electron beams overlap each other and are emitted to the measurement area
Implementation Method 2
emitting electrons from a high-speed electron gun and, as the electrons collide and interact with a surface of a sample, detecting and analyzing particles such as secondary electrons that bounce out of the sample
Data Source
AI summary
A semiconductor pattern measurement method includes extracting patterns for each type from patterns of a full-chip stored in a database, assigning an identification (ID) to the patterns, forming a two-dimensional grid structure on the full-chip, sorting the patterns in order from a pattern of the ID with a lowest frequency to a pattern of the ID with a highest frequency, assigning the sorted patterns to corresponding grids of the two-dimensional grid structure, and measuring the patterns assigned to the grids. In the measuring of the patterns, a separation distance is set between patterns that are measured based on the grids.