Stress-Buffer Layer for Sample Extraction in Energetic Beam Instruments
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Solution Overview
Problem
Existing methods for in situ lift-out of samples from substrates, such as semiconductor wafers, risk inducing mechanical stress and artifacts due to simultaneous attachment to multiple objects, leading to potential fractures and cracks during sample preparation.
Innovation Solution
A method involving the application of a stress-buffer layer over the region of interest, with controlled energetic beam cuts to isolate the sample while maintaining attachment only to the stress-buffer layer, thereby avoiding direct connection to objects that may move relative to each other, and ensuring the sample is never rigidly attached to two objects simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sample is attached to the end-effector before complete release from the substrate, then the sample can be manipulated and transferred, but mechanical stress and artifacts are induced due to simultaneous attachment to multiple objects
Solution Approach 1:
The sample is completely released from the substrate before attachment to the end-effector. This preliminary action of complete separation eliminates the harmful simultaneous attachment to multiple objects, preventing mechanical stress and artifacts while still enabling subsequent sample manipulation and transfer operations
Solution Approach 2:
The process is segmented into distinct sequential steps: first complete release from substrate, then attachment to end-effector. This segmentation prevents the overlapping attachment state that causes mechanical stress, while maintaining the ability to manipulate and transfer the sample through the end-effector
2Reliability
If the sample is completely released from the substrate before attachment to the end-effector, then mechanical stress and artifacts are minimized, but the process complexity increases
Solution Approach 1:
The harmful element of simultaneous attachment is extracted by enforcing complete release before end-effector attachment. This simple temporal separation rule eliminates mechanical stress without requiring complex additional equipment or procedures, maintaining process simplicity while ensuring sample integrity
3Ease of manufacture
If the sample remains attached to the substrate during end-effector connection, then the process is simpler, but fractures and cracks are created due to transient mechanical forces
Solution Approach 1:
Complete release from substrate is performed as a preliminary action before end-effector attachment. This ensures the sample is fully separated and not subject to transient mechanical forces during connection, preventing fractures and cracks while maintaining reasonable process simplicity through sequential rather than simultaneous operations
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 minimizes the risk of sample damage and artifacts by reducing mechanical stress, allowing for precise and reliable separation of the sample from the substrate without inducing fractures or cracks, while maintaining the sample's integrity for further analysis.
Implementation Method 1
A stress-buffer layer is applied over the region of interest... extending in at least one dimension past the region of interest
Implementation Method 2
A first cut with the energetic beam is made into the substrate on at least one side of the region of interest, and a second cut with the energetic beam is made into the substrate on an opposite side of the region of interest
Data Source
Figure 1~2
Figure 3
Figure 4A~4F
AI summary
A substrate located in an energetic-beam instrument has a region of interest to be extracted as a sample for further analysis. Cuts are made in the substrate to define a sample, and a stress-buffer layer is formed over the region of interest or adjacent to it. An isolating cut is made to separate the portion of the substrate containing the region of interest from the bulk substrate; however, the isolated area remains attached to the stress- buffer layer. An end-effector, such as the probe of a nano-manipulator, is attached to the stress-buffer layer, and the stress-buffer layer is cut to free the sample. The sample may then be attached to a holder by attachment of the stress-buffer layer thereto. Thus the sample is never at the same time connected directly and rigidly to two different objects that may move relatively to one another, creating undesirable stresses in the sample.