Monocrystalline Pad Transfer via Substrate Deformation
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Solution Overview
Problem
The existing transfer process for reconstituting substrates of single-crystal blocks onto a final substrate is inefficient due to the need for mechanical-chemical polishing to achieve coplanarity, which degrades the blocks and increases costs, especially when dealing with materials like SiC that are difficult to polish.
Innovation Solution
A transfer method that deforms the intermediate substrate to make the free surfaces of the blocks coplanar during assembly, eliminating or simplifying the need for planarization, and uses molecular adhesion and heat treatment to ensure proper attachment and detachment of the blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical-chemical polishing is performed to achieve coplanarity of block surfaces, then the blocks become coplanar and can be assembled, but the blocks are degraded and costs increase
Solution Approach 1:
The patent applies preliminary action by forming a sacrificial layer between the blocks and the intermediate substrate before assembly. This layer is deposited in advance and allows for thickness compensation, enabling blocks of varying thicknesses to achieve coplanarity without mechanical polishing that would degrade the blocks.
Solution Approach 2:
The patent uses an intermediary sacrificial layer (such as silicon dioxide or silicon nitride) deposited between the blocks and the intermediate substrate. This intermediary layer acts as a mediator that compensates for thickness variations, allowing blocks to be assembled at different heights while still achieving uniform coplanar surfaces without direct mechanical contact and degradation.
2Manufacturing precision
If mechanical-chemical polishing is performed to achieve coplanarity, then assembly becomes possible, but manufacturing costs increase
Solution Approach 1:
The sacrificial layer is deposited in advance using standard thin-film deposition techniques before block assembly. This preliminary action eliminates the need for costly mechanical-chemical polishing steps, reducing manufacturing costs while still achieving the required coplanarity for successful block assembly.
Solution Approach 2:
The intermediary sacrificial layer provides a cost-effective solution by enabling thickness compensation through low-cost deposition processes rather than expensive mechanical polishing, thereby reducing overall manufacturing costs while maintaining the precision needed for block assembly.
3Productivity
If blocks of different thicknesses are assembled without planarization, then processing time is reduced, but uniform adhesion to the final substrate cannot be achieved
Solution Approach 1:
The sacrificial layer is deposited in advance with thickness designed to compensate for block thickness variations. This preliminary action ensures that when blocks are assembled, their top surfaces become coplanar, enabling uniform adhesion to the final substrate without requiring time-consuming mechanical polishing steps, thus maintaining high productivity.
Solution Approach 2:
The intermediary sacrificial layer mediates between blocks of different thicknesses, providing a uniform surface for adhesion. This allows all blocks to adhere uniformly to the final substrate simultaneously without sequential processing, maintaining high transfer process efficiency while achieving the required manufacturing precision.
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 enhances the yield of the transfer process by avoiding the degradation of the blocks and reducing costs, while allowing for the transfer of blocks onto substrates larger than 200 mm in diameter, regardless of the original substrate size, by ensuring all blocks adhere uniformly.
Implementation Method 1
during the assembly stage, the intermediate substrate deforms so that the free surfaces of the blocks become coplanar
Implementation Method 2
step b of assembly is a molecular adhesion step
Implementation Method 3
step c of detachment includes a heat treatment
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a transfer method which comprises the following steps: a. providing an intermediate substrate (10), the intermediate substrates (10) comprising pads (20) on one of the surfaces thereof, said pads (20) being made of monocrystalline material, the pads (20) comprising an embrittlement area (50) defining a pad portion (70) intended for being transferred onto a final substrate (60); b. executing an assembly step by placing the free surface (40) of each of the pads (20) in contact with the final substrate (60); c. executing, after the assembly step, a detachment at the embrittlement area (50) of each of the pads (20); the transfer method being characterised in that during the assembly step, the intermediate substrate (10) deforms so that the free surfaces of the pads (20) become coplanar.