Semiconductor Edge Region P-Type Doping for Etching Stop Layer
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Solution Overview
Problem
During the fabrication of semiconductor devices, the edge region of the substrate is excessively polished, leading to damage and exposure of silicon material, which can result in the removal of substrate portions and affect device structures in the device region.
Innovation Solution
A P-type dopant layer is introduced in the edge region to act as an etching stop layer, converting the silicon material into a layer that protects it from etching, thereby preventing substrate damage and maintaining device structure integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a polishing process is used to planarize the surface and expose the dummy gate, then the dummy gate is exposed to facilitate subsequent removal, but the edge region is excessively polished causing silicon material exposure and potential substrate damage
Solution Approach 1:
The patent applies different treatments to different regions of the substrate: the device region undergoes standard polishing to expose dummy gates, while the edge region receives additional protection through P-type doping to create an etching stop layer. This local differentiation resolves the contradiction by allowing precise control over polishing effects in each region.
Solution Approach 2:
The P-type doping process is performed in advance on the edge region before the polishing and etching steps. This preliminary action creates the etching stop layer that prevents substrate damage during subsequent processing, addressing the harmful effect before it can occur.
2Manufacturing precision
If the edge region is excessively polished, then the silicon material is exposed, but this causes the substrate to be removed during etching and damages the device
Solution Approach 1:
The P-type doped layer serves as an intermediary etching stop layer between the polishing process and the subsequent etching process. It mediates the interaction between these two processes by being resistant to the etching chemicals, thereby protecting the underlying silicon substrate from being removed while still allowing the polishing to achieve surface planarization.
3Reliability
If P-type dopants are introduced to create an etching stop layer, then substrate damage is prevented, but the device density in the edge region must be reduced
Solution Approach 1:
The patent accepts a local reduction in device density in the edge region as a necessary trade-off to achieve substrate protection through P-type doping. The edge region is treated differently from the device region, with lower device density, to prevent substrate damage during processing.
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
The etching stop layer effectively reduces substrate damage in the edge region, ensuring that device structures in the device region are not affected, and allows for the successful formation of metal gate structures without compromising the substrate.
Implementation Method 1
A P-type doping process is performed in the edge region, and the silicon material exposed in the edge region and a top region of the substrate are converted into materials of an etching stop layer
Data Source
AI summary
A semiconductor device and a method for fabricating the same are provided. A structure of the semiconductor device includes a substrate having a device region and an edge region. A plurality of device structures is formed on the substrate. An etching stop layer is disposed in the edge region of the substrate. The etching stop layer is converted from P-type dopants from an exposed surface layer of the substrate.