Hydrogenated Amorphous Silicon Detachable Bonding
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Solution Overview
Problem
Current detachable bonding methods for thin wafer or die layer transfer are inefficient, environmentally unfriendly, and result in low thickness uniformity, with existing techniques like water-enhanced de-bonding, gas or water-jet de-bonding, wax bonding, plasma removal, and laser ablation having limitations such as low bonding energy, damage risk, and complexity in achieving strong and uniform bonds.
Innovation Solution
A method involving the formation of a hydrogenated amorphous silicon or silicon oxide layer on substrates, allowing for bonding at low temperatures and subsequent detachment by heating, which releases hydrogen to create pressure and split the substrates, enabling efficient transfer of thin layers with high bond strength and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If water-enhanced de-bonding or gas/water-jet de-bonding is used, then detachment can be achieved, but bonding energy is insufficient and damage risk increases
Solution Approach 1:
The patent changes the bonding method from water/gas-enhanced de-bonding to direct thermal bonding, altering the bonding parameters to achieve sufficient bond strength without damaging the substrates. The bonding process uses controlled heating to form strong bonds between substrates while avoiding the damage risks associated with jet de-bonding methods.
Solution Approach 2:
The patent replaces mechanical de-bonding systems (water jets, gas jets) with a thermal bonding system. Instead of using high-pressure fluid jets to separate substrates, the invention uses controlled thermal fields to both bond and subsequently detach substrates through hydrogen release, eliminating the mechanical damage risks of jet methods.
2Manufacturing precision
If mechanical grinding, polishing or selective etching is used to remove handle substrate, then layer transfer can be achieved, but the process is time consuming and results in low thickness uniformity
Solution Approach 1:
The patent replaces mechanical removal methods (grinding, polishing, etching) with a thermal release mechanism. By incorporating hydrogenated amorphous silicon layer that releases hydrogen upon heating, the handle substrate can be detached cleanly without mechanical contact, achieving superior thickness uniformity and reducing process time compared to traditional mechanical methods.
Solution Approach 2:
The patent utilizes the phase transition and chemical changes of hydrogenated amorphous silicon when heated. The hydrogen release upon thermal processing causes the bonded structure to split, enabling clean separation of the transferred layer from the handle substrate without mechanical intervention, thereby achieving high thickness uniformity and reduced processing time.
3Stability of the object's composition
If low temperature bonding is used for dissimilar materials, then thermal expansion mismatch is avoided, but bond strength is reduced
Solution Approach 1:
The patent changes the bonding temperature parameter to low temperature processing, which prevents thermal expansion mismatch in dissimilar materials. The hydrogenated amorphous silicon layer enables sufficient bond strength at these lower temperatures through direct bonding mechanisms, resolving the contradiction between maintaining thermal stability and achieving strong bonds.
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 provides a strong, uniform, and efficient bonding solution that allows for the transfer of thin layers with high bond strength, overcoming the limitations of existing techniques by achieving bond energies sufficient for processing steps like CMP and etching, while being environmentally friendly and reducing substrate thickness uniformly.
Implementation Method 1
heating the bonded structure at a temperature to detach the first element from the bonded structure
Implementation Method 2
heating the bonded structure at a temperature to detach the first element from the bonded structure
Data Source
AI summary
A method for detachable bonding that forms an amorphous silicon layer, or a silicon oxide layer with a high hydrogen content, on an element such as a carrier substrate. A second element, such as a substrate, is bonded to the amorphous silicon layer or silicon oxide layer, and the second element may then have a portion removed. A third element, such as a host or carrier substrate, is bonded to the second element or to the remaining portion of the second element to form a bonded structure. The bonded structure is then heated to cause the first element to detach from the bonded structure.