Edge-Chamfered Substrate With Buried Insulating Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for forming edge-chamfered substrates with buried insulating layers often result in damage to the original cover layer, leading to substrate warp and defects, and struggle to control the edge chamfering process effectively.
Innovation Solution
A method involving edge grinding and spin etching is employed to chamfer the substrate, allowing for precise removal of the edge of the top semiconductor layer without etching the back cover layer, thereby preserving the substrate's warp integrity and ensuring concentricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hydrofluoric acid is used to etch off silicon dioxide residual on the edge, then the silicon dioxide can be removed, but the thermal-oxidation silicon dioxide cover layer on the handle substrate surface is destroyed and the warp balance is affected
Solution Approach 1:
The patent applies local quality by using spin etching to selectively remove silicon dioxide only at the edge region where it accumulates, while preserving the cover layer on the handle substrate surface. The spin etching process creates a localized effect where the centrifugal force directs the etchant primarily to the edge area, achieving precise removal without damaging the overall substrate structure or warp balance.
2Manufacturing precision
If edge grinding is performed followed by TMAH immersion to remove excess silicon, then the edge silicon can be removed, but many undesired defects are introduced after TMAH immersion
Solution Approach 1:
The patent extracts the harmful TMAH immersion step from the process sequence and replaces it with spin etching. By removing the TMAH immersion step that causes defects, the invention achieves edge silicon removal through a cleaner process that doesn't introduce unwanted contaminants or defects to the substrate.
3Ease of manufacture
If oxide polishing solution is used to remove edge residual silicon dioxide without chamfer grinding, then the process steps are reduced, but the shape of edge chamfer is not easy to control and concentricity is difficult to ensure
Solution Approach 1:
The patent merges the chamfer grinding step with the spin etching process, combining mechanical removal (grinding) and chemical removal (etching) into a unified process sequence. This integration allows the edge chamfer shape to be controlled by the grinding step while the spin etching subsequently cleans up residual silicon dioxide, achieving both shape control and process efficiency.
4Manufacturing precision
If multiple processing steps are used to achieve edge chamfering, then the edge can be processed, but the amount of removing edge is hard to control resulting in remaining silicon oxide and destroyed warp degree
Solution Approach 1:
The patent replaces the complex multi-step mechanical processing system with a spin etching process that uses centrifugal force to control the etching action. This substitution allows precise control of edge removal through rotational speed and etchant flow rate, reducing the number of processing steps while improving control over the amount of material removed and preventing warp degree destruction.
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 approach effectively avoids edge collapses in subsequent processes and maintains the substrate's warp integrity by selectively etching the edge of the top semiconductor layer using spin etching, improving control and uniformity over traditional methods.
Implementation Method 1
by spin etching, etching the first substrate which is exposed by edge grinding on the etching mask layer
Implementation Method 2
chamfering the first substrate and the etching mask layer on the surface of the first substrate by edge grinding
Data Source
Figure 1~4
Figure 5~8
Figure 9~11
AI summary
A method for forming an edge-chamfered substrate with a buried insulating layer is provided, which comprises the following steps: providing a first substrate (S10); forming an etching mask layer on surfaces of the first substrate, wherein said etching mask layer is formed on the whole surfaces of the first substrate (S11); chamfering a glazed surface of the first substrate and the etching mask layer thereon by the edge grinding (S12); by rotary etching, etching the first substrate which is exposed by the edge grinding on the etching mask layer (S13); providing a second substrate (S14); and bonding the first substrate to the second substrate with a buried insulating layer (S15). The method avoids the edge collapses and the changes of the warp degree in subsequent processes.