Transferred Alignment Marks for Precise Multi-Substrate Bonding
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Solution Overview
Problem
Current semiconductor fabrication techniques face challenges in achieving precise alignment of alignment marks across different substrates, particularly for super hard, difficult-to-etch, or chemically sensitive materials, and require costly and skill-intensive methods, which are inefficient for mass transfer and 3D integrated systems.
Innovation Solution
A method and system for transferring alignment marks between substrate systems using physical structures formed during semiconductor fabrication, allowing for precise alignment and bonding across multiple substrates, including the use of temporary and mass transfer substrates with adhesive layers, enabling the maintenance of alignment during etching and conductor deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography is used to form alignment marks on substrates, then alignment marks can be created, but the method is costly and requires high skill levels and precision tools
Solution Approach 1:
The alignment marks are formed during the frontend fabrication process on the same substrate as the semiconductor devices, before the substrate is transferred to backend systems. This preliminary formation of alignment marks eliminates the need for separate mark creation steps in backend systems, reducing complexity and cost while maintaining precision.
Solution Approach 2:
The alignment marks serve multiple functions: they are used for device fabrication alignment during frontend processing and continue to serve as reference marks for backend processing steps including stamping, pick-and-placement, and wire bonding. This multi-functionality eliminates the need for separate alignment mark systems in different substrate systems.
2Ease of operation
If alignment marks are placed proximate to but not exactly on the alignment point, then substrate handling is simplified, but alignment precision for future processing steps is greatly reduced
Solution Approach 1:
Alignment marks are formed at the exact locations where alignment is needed during frontend fabrication, rather than placing them proximate to alignment points. This preliminary positioning ensures maximum alignment precision for all subsequent processing steps while the automated handling systems maintain operational ease.
3Manufacturing precision
If electrical connections are used for alignment marks, then alignment can be achieved, but the method does not work on super hard, difficult-to-etch, or chemically sensitive substrates
Solution Approach 1:
Instead of using electrical connections that require conductive paths on the substrate, the invention uses physical/optical copies of alignment marks formed during fabrication. These marks can be read optically without requiring electrical connections, making them compatible with super hard, difficult-to-etch, and chemically sensitive substrates while maintaining alignment precision.
4Manufacturing precision
If alignment marks are transferred between different substrates using stacking and photolithography, then alignment can be achieved, but the process is very costly and requires expensive stepping tools
Solution Approach 1:
Alignment marks are formed during the frontend fabrication process on the original substrate before any transfer operations. When substrates are stacked and transferred to backend systems, these pre-formed marks are physically transferred with the substrate, eliminating the need for expensive stepping tools and complex photolithography alignment processes during mass transfer operations.
Solution Approach 2:
The alignment marks serve themselves by being formed as integral parts of the substrate fabrication process and automatically transferring with the substrate through stacking operations. This self-service approach eliminates the need for separate, expensive alignment tooling and processes in backend systems.
Data Source
AI summary
A method for transferring alignment marks between substrate systems includes providing a substrate having semiconductor devices and alignment marks in precise alignment with the semiconductor devices; and physically transferring and bonding the semiconductor devices and the alignment marks to a temporary substrate of a first substrate system. The method can also include physically transferring and bonding the semiconductor devices and the alignment marks to a mass transfer substrate of a second substrate system; and physically transferring and bonding the semiconductor devices and the alignment marks to a circuitry substrate of a third substrate system. A system for transferring alignment marks between substrate systems includes the substrate having the semiconductor devices and the alignment marks in precise alignment with the semiconductor devices. The system also includes the first substrate system, and can include the second substrate system and the third substrate system.