Defect-Free Semiconductor Bonding via Reaction Annealing
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Summary
Problems
The assembly of semiconductor substrates by molecular adhesion often results in bonding defects, such as bubbles, which can lead to poor electrical and thermal conduction and structural integrity issues, particularly when subjected to high temperatures or thinning processes like Smart Cut.
Innovation solutions
A process involving intimate contact of substrates, reaction annealing at a specific temperature to generate bubbles, partial separation to eliminate these bubbles, and re-contacting in a controlled atmosphere to reform the assembly, ensuring minimal defects and maintaining good conduction properties.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If substrates are assembled by molecular adhesion with water layer present, then adhesion forces are created between substrates, but bonding defects such as bubbles form at the bonding interface
Why choose this principle:
The patent applies preliminary action by performing a first heat treatment at a first temperature (e.g., 200-400°C) before final assembly to pre-react surface groups and reduce water content. This preliminary treatment prepares the substrate surfaces to minimize bubble formation during subsequent high-temperature bonding, thereby improving adhesion quality while preventing bonding defects.
Principle concept:
If substrates are assembled by molecular adhesion with water layer present, then adhesion forces are created between substrates, but bonding defects such as bubbles form at the bonding interface
Why choose this principle:
The patent employs parameter changes by controlling temperature progression through multiple heat treatment stages (first temperature below second temperature, with specific duration ratios). The bonding interface is treated at different temperature levels to sequentially achieve water removal, surface activation, and final bonding, transforming the bonding process parameters to eliminate defects while maintaining reliable adhesion.
Application Domain
Data Source
AI summary:
A process involving intimate contact of substrates, reaction annealing at a specific temperature to generate bubbles, partial separation to eliminate these bubbles, and re-contacting in a controlled atmosphere to reform the assembly, ensuring minimal defects and maintaining good conduction properties.
Abstract
The invention relates to a method of joining two semi-conductor substrates by molecular adhesion, comprising: a step a) of bringing a first and a second substrate (2) into close contact in order to form an assembly having a bonding intcerface (4), a step b) of reaction annealing the bonding interface (4) at a first temperature higher than a first predetermined temperature, said step b) generating bubbles at the joining interface, a step c) of at least partially detaching the two substrates at the bonding interface (4) in order to eliminate the bubbles, and a step d) of bringing the first and the second substrate (2) into close contact again at the bonding interface (4) in order to reform the assembly.