Fabricating Submicron Suspended Objects for Mechanical Characterization
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Solution Overview
Problem
Current methods for determining mechanical properties of submicron objects in microelectronics are inadequate as they do not accurately represent the properties at the submicron scale, as these objects are typically cut from larger materials, leading to different physical phenomena and properties.
Innovation Solution
A method involving the fabrication of submicron suspended objects by depositing a void layer, a transfer layer, and a hard mask, followed by etching to suspend the objects, allowing for accurate mechanical and electrical characterization using nano-indentation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If submicron objects are cut from larger materials using focused ion beam, then mechanical properties can be determined, but the properties do not accurately represent the submicron scale characteristics
Solution Approach 1:
The patent applies preliminary action by fabricating submicron objects with precise dimensions during the manufacturing process itself, rather than cutting them later from larger materials. The objects are created with controlled width (50-300 nm) and length (several microns) through deposition and lithography techniques, ensuring they represent true submicron-scale material properties from the outset.
Solution Approach 2:
The patent extracts the submicron objects from their original support structure by etching away the surrounding material. This creates suspended objects that are isolated from the bulk material, allowing measurement of intrinsic submicron-scale properties without interference from the larger substrate. The objects are released by etching the sacrificial layer beneath them.
2Reliability
If submicron objects rest on a support, then they can be fabricated and handled, but their electrical insulation is insufficient and mechanical properties cannot be accurately characterized
Solution Approach 1:
The patent extracts submicron objects from their support structure by etching away the sacrificial layer beneath them, creating suspended objects. This provides perfect electrical insulation since air replaces the insulating layer, and enables accurate mechanical characterization through techniques like nano-indentation without substrate interference.
Solution Approach 2:
The patent uses a sacrificial layer (silicon dioxide or silicon nitride) as an intermediary during fabrication. This layer supports the objects during manufacturing but is subsequently removed to release the objects. The transfer layer acts as another intermediary to enable pattern transfer and object release without damaging the submicron structures.
3Manufacturing precision
If submicron objects are fabricated with precise dimensions, then they represent true submicron-scale properties, but the fabrication process becomes more complex
Solution Approach 1:
The patent segments the fabrication process into distinct functional layers: a support layer, a sacrificial void layer (silicon dioxide or silicon nitride), a transfer layer, and the submicron object layer. Each layer serves a specific purpose and can be processed independently, allowing precise control of object dimensions while managing process complexity through modular fabrication steps.
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
Enables precise mechanical and electrical property characterization of submicron objects, improving the design and reliability of microelectronic components by representing their properties at the submicron scale, with suspended objects providing better isolation and accessible testing methods.
Implementation Method 1
etching the combination formed by the hard mask, the transfer layer and the void layer to eliminate the hard mask and the portion of the transfer layer in the region and to open up the portion of the void layer under the region
Data Source
AI summary
A method of fabricating submicron objects that includes the following steps: depositing a void layer on a support, depositing a transfer layer on the void layer, producing the objects in the transfer layer, producing a hard mask on a portion of the transfer layer to delimit a region comprising a portion of the objects, and etching the combination formed by the hard mask, the transfer layer and the void layer to eliminate the hard mask and the portion of the transfer layer in the region and to open up the portion of the void layer under the region so that the objects are suspended, the rate of etching the void layer being greater than the rate of etching the transfer layer and the hard mask.