Bilayer Electrical Conductors for Oxide-Tolerant Transfer Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for electrically connecting small integrated circuits to target substrates are costly and complex, often requiring multiple photolithographic steps and are hindered by topographical differences and non-conductive layers formed in ambient conditions.
Innovation Solution
A bilayer electrical conductor structure with a first layer that forms a non-conductive layer in ambient conditions and a second layer that does not, allowing connection posts to be forcefully wedged into contact pads, potentially welded, and optionally heat-treated for improved conductivity.
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 interconnection is achieved, but the process becomes expensive and complex with multiple manufacturing steps
Solution Approach 1:
The patent extracts the electrical connection function from the complex photolithographic process by using pre-formed conductive connection posts on chiplets that directly contact backplane contact pads. This eliminates the need for multiple photolithographic steps including metal evaporation, sputtering, photoresist coating, exposure, and etching, thereby simplifying the manufacturing process while maintaining reliable electrical connections.
Solution Approach 2:
The connection posts are pre-formed on the chiplets before transfer to the backplane. This preliminary formation of conductive structures allows the electrical connection function to be established in advance, eliminating the need for complex post-transfer photolithographic processing steps and reducing overall manufacturing complexity.
2Reliability
If photolithographic processes are used to form electrical connections, then electrical interconnection is achieved, but the number of manufacturing steps increases and costs increase
Solution Approach 1:
The patent removes the cumbersome photolithographic manufacturing steps by extracting the electrical connection function to pre-formed connection posts on chiplets. This extraction reduces the number of manufacturing steps from multiple photolithographic cycles to a single transfer and contact operation, thereby improving manufacturing efficiency and reducing costs while maintaining connection reliability.
3Reliability
If conventional electrical connection methods are used, then connections are formed, but topographical differences between small integrated circuits and target substrate hinder continuous conductor formation
Solution Approach 1:
The patent resolves the topographical barrier by transitioning from planar conductor formation to three-dimensional point contact. The connection posts extend vertically from the chiplet surface, allowing electrical contact to be established at a different dimensional level that bridges the height difference between chiplets and backplane, thereby enabling continuous electrical connection despite topographical variations.
Solution Approach 2:
The connection posts serve as intermediary structures that mediate the electrical connection between chiplets and backplane contact pads. These posts act as physical and electrical bridges that overcome the topographical discontinuity, allowing continuous conductor formation without requiring complex photolithographic patterning across uneven surfaces.
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
Facilitates efficient and cost-effective electrical connections between small integrated circuits and target substrates with reduced process steps, maintaining conductivity despite ambient conditions.
Implementation Method 1
A viscoelastic elastomer stamp is pressed against the process side of the chiplets on the native source wafer, adhering each chiplet to an individual stamp post.
Implementation Method 2
The connection posts, the target substrate contact pads, or both the connection posts and the target substrate contact pads can be deformed or crumpled and the connection post can be driven into or through the target substrate contact pad
Implementation Method 3
As a consequence, the connection post can be welded to the target substrate contact pad. 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.