Multilayer Conductors for Transfer Printing Without Oxide Contact Loss
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Solution Overview
Problem
Existing methods for electrically interconnecting small integrated circuits or chiplets to backplane contact pads are costly and complex, particularly due to topographical differences and the formation of non-conductive layers when exposed to air, which inhibit the formation of reliable electrical connections.
Innovation Solution
The use of micro-transfer printing with electrically conductive connection posts that protrude from the components and are forcibly wedged into target substrate contact pads, potentially with a second layer that prevents non-conductive layer formation, allowing for direct electrical connection without additional material deposition or patterning, and optionally followed by heat treatment for welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photolithographic processes are used to form electrical connections between small integrated circuits and backplane contact pads, then electrical connections can be established, but the process becomes expensive and complex with multiple manufacturing steps
Solution Approach 1:
The patent extracts the connection post formation from the traditional photolithographic process. Connection posts are formed directly on the chiplet surfaces using deposition techniques, separating this function from the subsequent photolithographic patterning steps. This extraction simplifies the overall manufacturing process while maintaining reliable electrical connections between chiplets and backplane contact pads.
Solution Approach 2:
The patent performs preliminary formation of connection posts on chiplet surfaces before the actual assembly and bonding process. By pre-forming these conductive structures, the patent eliminates the need for complex in-situ patterning and material deposition during final assembly, thereby reducing manufacturing complexity while ensuring reliable electrical connectivity.
2Reliability
If additional layers such as interlayer dielectric insulators are added to the photolithographic process, then electrical isolation is improved, but the number of manufacturing steps and cost increase
Solution Approach 1:
The patent merges the electrical isolation function with the connection post structure itself. By designing the connection posts with integrated isolation features or by forming isolation layers concurrently with connection post formation, the patent combines multiple functions into fewer process steps, thereby improving manufacturing efficiency while maintaining reliable electrical isolation.
Solution Approach 2:
The connection post structure is designed to serve multiple functions simultaneously: providing electrical connection, mechanical support, and electrical isolation. This multi-functionality eliminates the need for separate interlayer dielectric layers in many cases, reducing the number of manufacturing steps while maintaining proper electrical isolation between conductive elements.
3Reliability
If metal layers are evaporated or sputtered onto small integrated circuits and target substrate, then electrical connections are formed, but topographical differences in height make continuous conductor formation difficult
Solution Approach 1:
The patent addresses topographical challenges by transitioning from planar conductor formation to three-dimensional connection post structures. Connection posts extend vertically from chiplet surfaces to bridge height differences, enabling continuous electrical pathways across non-planar surfaces without requiring complex in-situ conductor patterning and deposition techniques.
Solution Approach 2:
The connection posts serve as intermediary structures between chiplet surfaces and backplane contact pads. These posts provide a mechanical and electrical bridge that overcomes topographical discontinuities, allowing simple planar conductor formation on the backplane while maintaining reliable electrical connectivity to elevated chiplet surfaces.
4Reliability
If conventional connection methods are used, then electrical interconnection is achieved, but the process is costly and requires additional material deposition and patterning
Solution Approach 1:
The patent extracts the connection post formation and electrical connection functions from the traditional photolithographic material deposition and patterning process. By pre-forming connection posts on chiplets and using them as direct contact points, the patent eliminates unnecessary intermediate deposition and patterning steps, reducing manufacturing complexity while maintaining reliable electrical interconnection.
Solution Approach 2:
The connection posts are designed to self-align and self-contact with backplane contact pads during assembly, eliminating the need for complex alignment and patterning processes. This self-service approach simplifies manufacturing by allowing direct mechanical and electrical contact without additional material deposition or sophisticated patterning 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
This method simplifies the electrical interconnection process, reduces costs, and provides robust, reliable connections between small integrated circuits and target substrates, compatible with common photolithographic processes, while avoiding the challenges of non-conductive layer formation.
Implementation Method 1
the first layer comprises a first electrical conductor that forms a non-conductive layer on a surface of the first electrical conductor when exposed to air
Implementation Method 2
An additional heat treatment can be provided to facilitate the welding
Data Source
AI summary
An electrical conductor structure comprises a substrate and an electrical conductor disposed on or in the substrate. The electrical conductor comprises a first layer and a second layer disposed on a side of the first layer opposite the substrate. The first layer comprises a first electrical conductor that forms a non-conductive layer on a surface of the first electrical conductor when exposed to air and the second layer comprising a second electrical conductor that does not form a non-conductive layer on a surface of the second electrical conductor when exposed to air. A component comprises a connection post that is electrically connected to the second layer and the electrical conductor. The first and second layers can be inorganic. The first layer can comprise a metal such as aluminum and the second layer can comprise an electrically conductive metal oxide such as indium tin oxide.