Nanoporous Bump Transfer Bonding for Sensitive Substrates
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Solution Overview
Problem
The existing chemical de-alloying process for producing nanoporous bumps on substrates can damage sensitive semiconductor materials, and it is challenging to produce nanoporous bumps on substrates of varying sizes, including individual chips.
Innovation Solution
A method involving the use of two substrates, where a nanoporous bump is first produced on a first substrate that can withstand the de-alloying process, and then transferred to a second substrate with sensitive materials through compression bonding, allowing for the separation of the substrates and transfer of the bump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a chemical de-alloying process is used to produce nanoporous bumps on substrates, then nanoporous bumps can be produced, but the substrate material or material placed on the substrate is damaged
Solution Approach 1:
The process is divided into two separate stages: first producing the nanoporous bump on a sacrificial substrate, then transferring it to the final substrate. This segmentation allows the damaging de-alloying process to occur only on the sacrificial substrate, protecting the final substrate from damage while still achieving the desired nanoporous bump structure.
Solution Approach 2:
A sacrificial substrate acts as an intermediary carrier that temporarily holds the nanoporous bump during production. This intermediary allows the bump to be formed using aggressive chemistry on the sacrificial substrate, then transferred to the final substrate without exposing it to damaging chemicals.
2Adaptability or versatility
If different systems (sputtering, lithography, electroplating) are available depending on wafer size, then various wafer sizes can be processed, but costs increase and system flexibility is reduced
Solution Approach 1:
The nanoporous bump production system becomes universal by producing bumps on a standardized sacrificial substrate that can then be transferred to various final substrates of different sizes and types. This multi-functional approach allows the same bump production equipment to serve multiple applications, eliminating the need for separate systems for different wafer sizes.
Solution Approach 2:
The bump production process is extracted from the final substrate and performed on a separate sacrificial substrate. This extraction allows the bump formation system to be independent of the final substrate specifications, enabling a single standardized system to produce bumps for various applications.
3Adaptability or versatility
If individual chips are used instead of wafers, then multi-project wafer sharing is not possible, but substrate format flexibility is improved
Solution Approach 1:
The process segments chip production by first creating bumps on a large sacrificial wafer containing multiple chips, then separating and transferring individual chips with their bumps to final substrates. This segmentation enables both the productivity benefits of wafer-scale processing and the flexibility of individual chip customization.
Solution Approach 2:
The nanoporous bumps are preliminarily formed on the sacrificial wafer before chip separation. This preliminary action allows efficient batch processing of multiple chips while maintaining the flexibility to select and transfer only specific chips to final substrates based on customer requirements.
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 enables the production of nanoporous bumps on sensitive substrates and individual chips without damaging them, while also increasing system flexibility and reducing costs associated with different wafer sizes.
Implementation Method 1
electrodepositing a metal alloy by applying a voltage
Implementation Method 2
de-alloying the metal alloy to produce a nanoporous bump
Implementation Method 3
compression bonding the nanoporous bump to the second substrate, wherein a bump top side facing away from the first substrate is welded to the connection metallization of the second substrate
Data Source
AI summary
A method for producing a substrate having a nanoporous bump may comprise providing a first substrate and a second substrate. The second substrate having a connection metallization. The method may further include electrodepositing a metal alloy by applying a voltage and de-alloying the metal alloy to produce a nanoporous bump. The method may further include compression bonding the nanoporous bump to the second substrate. A bump top side facing away from the first substrate is welded to the connection metallization of the second substrate. After the compression bonding, the second substrate is separated from the first substrate and the nanoporous bump is at least partially transferred from the first substrate to the second substrate.