TEM Sample Stack Structure Eliminating Curtain Effect
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Solution Overview
Problem
The curtain effect in TEM sample preparation leads to uneven and damaged surfaces, affecting the quality of structural analysis and characterization, especially with shrinking device sizes and low voltage milling, and existing methods like tilting or backside polishing are inefficient or hazardous.
Innovation Solution
A method combining backside milling and dicing to create a sample stack structure with a target layer attached to a dummy substrate via an adhesive layer, eliminating the curtain effect by forming specific trenches and vias, and using epoxy resin as the adhesive, which allows for precise localization and uniform thinning without tilting or hazardous chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If backside polishing is used to eliminate the curtain effect, then the curtain effect is completely eliminated, but the sample thickness needs to be reduced first which is time consuming and requires more work for specific location analysis
Solution Approach 1:
The invention divides the sample preparation into two separate dice: a sample dice containing the region of interest and a dummy dice serving as a support substrate. This segmentation allows the target layer to be transferred to a fresh substrate without requiring extensive thinning of the entire sample, thereby eliminating the curtain effect while reducing time consumption.
Solution Approach 2:
The invention introduces an adhesive layer as an intermediary between the target layer and the dummy substrate. This adhesive layer enables the transfer and attachment of the target layer to the dummy substrate, allowing the sample to be prepared without time-consuming thinning while still eliminating the curtain effect.
2Manufacturing precision
If polishing or dipping in acid to remove top layers is used to reduce the curtain effect, then the curtain effect is reduced, but the process becomes dangerous and complex
Solution Approach 1:
The invention extracts the target layer from the original substrate using a dicing saw to create separate sample and dummy dice. This mechanical extraction method replaces dangerous chemical processes (acid dipping) and complex polishing procedures, achieving curtain effect elimination while improving process safety and simplicity.
Solution Approach 2:
The invention replaces chemical methods (acid dipping) and mechanical polishing with a mechanical dicing approach. The dicing saw physically separates the target layer from the substrate, eliminating the need for hazardous chemicals and complex multi-step processes, thereby improving ease of manufacture.
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 completely eliminates the curtain effect, ensuring high-quality TEM analysis with optimal sample thickness and precision, enhancing the efficiency and safety of the sample preparation process.
Implementation Method 1
the target layer of the sample dice is attached to the substrate of the dummy dice by an adhesive layer
Implementation Method 2
a method for preparing a sample stack structure by a combination of backside milling and dicing
Data Source
AI summary
The present invention provides a sample stack structure with multiple layers. The sample stack structure has at least a substrate, an adhesive layer and a target layer. The target layer is directly sandwiched between the substrate and the adhesive layer.