Trench Isolation Structure With Selective Corner Protection
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Solution Overview
Problem
The existing trench isolation structure formation methods in semiconductor wafers often damage active regions during the etching process, compromising the performance of semiconductor devices.
Innovation Solution
A method involving the formation of a trench isolation structure with a protection layer that has etching selectivity, created through ion implantation and decoupled plasma treatment, to prevent damage to active regions during the etching process by forming damage regions with higher etching rates and transforming them into protection layers with lower etching rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an etching process is used to adjust the height of the insulating material, then the height can be precisely controlled, but the active regions of the semiconductor devices may be subjected to damages
Solution Approach 1:
The patent introduces a protection layer as an intermediary substance between the etchant and the active regions. This protection layer is formed by ion implantation into the insulating material, creating a region with different etching characteristics that prevents the etchant from reaching and damaging the active regions while still allowing the etching process to proceed for height adjustment.
Solution Approach 2:
The patent applies ion implantation to form a protection layer before performing the etching process. This preliminary action modifies the insulating material in advance to create a protective barrier, ensuring that when the etching subsequently occurs, the active regions are already shielded from potential damage.
2Manufacturing precision
If ion implantation is performed to form damage regions with higher etching rates, then the etching selectivity is improved, but the process complexity increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the insulating material through ion implantation. By introducing ions into the material, it creates damage regions with modified structural parameters that result in higher etching rates, thereby achieving the desired etching selectivity without requiring multiple different materials.
Solution Approach 2:
The patent converts the harmful effect of ion implantation (which creates damage regions) into a beneficial outcome. The damage regions, which initially seem detrimental to material integrity, are actually exploited to create the desired high etching rate regions that provide the necessary etching selectivity for the isolation structure formation.
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 effectively protects the top corners of active regions from etchant penetration, preventing damage and maintaining the performance of semiconductor devices.
Implementation Method 1
performing a decoupled plasma treatment, to transform a portion of the first damage region and a portion of the second damage region into a protection layer
Implementation Method 2
performing a first ion implantation process, during which first ions strike the second recess from a first side of the second recess, to form a first damage region at least in the first isolation material layer
Data Source
AI summary
A method for forming an isolation structure includes: forming a trench at a surface of a substrate; forming a mask pattern on the substrate, wherein the mask pattern has an opening communicated with the trench; filling a first isolation material layer in the opening and the trench, wherein a surface of the first isolation material layer defines a first recess; filling a second isolation material layer into the first recess; partially removing the first and second isolation material layers, to form a second recess, performing first and second oblique ion implantation processes, to form damage regions in the first isolation material layer; performing a decoupled plasma treatment, to transform portions of the damage regions into a protection layer having etching selectivity with respect to the damage regions; and removing the damage regions.