Semiconductor Subsurface Structure Measurement via Multi-Focal SEM Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Scanning electron microscopes struggle to provide clear images of structures below the surface layer of semiconductor devices, leading to blurred images and high failure rates in property measurements due to physical limitations in electron transmission.
Innovation Solution
A method involving obtaining and adjusting SEM images of both surface and subsurface layers, generating a combined image to enhance contrast, identifying and calculating offsets between structures, and calculating sub-offsets to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scanning electron microscope is used to measure structures in fine scale, then measurement precision is improved, but image clarity of subsurface structures deteriorates due to electron transmission limitations
Solution Approach 1:
The patent divides the measurement process into multiple focal plane acquisitions, capturing images at different depths (surface layer and subsurface layers separately). Each image is processed and aligned independently, then combined to produce a composite image that preserves clarity from multiple focal planes, resolving the contradiction between fine-scale measurement and subsurface image quality.
Solution Approach 2:
The patent introduces the dimension of focal plane depth by acquiring images at multiple focal distances. Instead of attempting to capture all layers in a single focal plane, the system measures structures across the depth dimension, acquiring sharp images of both surface and subsurface structures at different focal planes and combining them computationally.
2Reliability
If multiple images are combined to enhance subsurface structure clarity, then image quality is improved, but processing complexity increases
Solution Approach 1:
The patent creates multiple copies of the same physical structure imaged at different focal planes. Each focal plane produces a copy of the structure at different depth focus, and these copies are computationally aligned and combined. This copying approach simplifies the combination process by treating each focal plane image as a separate dataset that can be independently processed and then merged.
Solution Approach 2:
The patent introduces computational alignment and registration as intermediary processes between raw image acquisition and final composite image generation. These intermediary steps automatically align images from different focal planes based on feature matching, reducing the complexity of manual image combination while maintaining high image quality.
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 approach enhances the clarity of subsurface structures in SEM images, reducing measurement failure rates and enabling more accurate analysis of semiconductor devices.
Implementation Method 1
the scanning electron microscope is utilized to measure structures of semiconductor devices in a fine scale through the transmission of electrons
Data Source
AI summary
The present disclosure provides a method of measuring a semiconductor device, including the following operations: obtaining a first image corresponding to a first layer in the semiconductor device; obtaining a second image corresponding to a second layer, below the first layer, in the semiconductor device, wherein the first layer includes at least one first structure and the second layer includes a plurality of second structures that are overlapped by the at least one first structure; generating a third image by combining the first image and the second image; and calculating an offset between the at least one first structure and the plurality of second structures based on the first image and the third image.