Semiconductor Isolation Structure With Slanted High-k Sidewalls
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Solution Overview
Problem
The shadowing effect of high-k dielectric layers and plasma charging at isolation layers during the formation of insulating structure openings in semiconductor devices leads to portions of fin structures and substrate remaining adjacent to STI regions, increasing leakage current and decreasing device reliability and performance.
Innovation Solution
The high-k dielectric layers and isolation layers are partially removed to form slanted sidewalls at the top portions of STI regions, reducing the shadowing and plasma charging effects, allowing for the removal of additional fin structures and substrate, thereby forming insulating structures that reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-k dielectric layers and isolation layers are kept intact during insulating structure formation, then device structure完整性 is maintained, but shadowing effect and plasma charging increase leading to higher leakage current
Solution Approach 1:
The patent applies preliminary action by removing portions of the high-k dielectric layer and isolation layer before forming the insulating structure. This pre-removal creates slanted sidewalls that eliminate the shadowing effect and reduce plasma charging, allowing the subsequent insulating structure formation to proceed without the harmful effects that would otherwise occur. The preliminary modification of the structure enables the final structure to achieve lower leakage current.
Solution Approach 2:
The patent extracts or removes specific portions of the high-k dielectric layer and isolation layer to eliminate the source of the shadowing effect and plasma charging. By taking out these problematic portions, the patent directly addresses the harmful factors generating leakage current while preserving the necessary structural integrity for device operation.
2Manufacturing precision
If high-k dielectric layers are partially removed to form slanted sidewalls, then shadowing effect is reduced improving insulating structure formation, but additional process steps are required
Solution Approach 1:
The patent performs preliminary removal of the high-k dielectric layer and isolation layer to create slanted sidewalls before forming the insulating structure. This preliminary action improves the precision of insulating structure formation by eliminating the shadowing effect, ensuring that the insulating material is deposited uniformly and that the final structure has the desired geometry without defects caused by shadowing.
3Reliability
If more fin structures and substrate are removed to form insulating structures, then leakage current is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-removing portions of the high-k dielectric layer and isolation layer to create slanted sidewalls. This preliminary modification enables subsequent etching processes to more easily and precisely remove the fin structures and substrate material, reducing the overall manufacturing complexity compared to attempting to achieve the same result without the preliminary structure modification.
Data Source
AI summary
The present disclosure describes a structure that provides insulation in a semiconductor device and a method for forming the structure. The structure includes a first isolation structure including a first isolation layer disposed on a substrate, a second isolation layer disposed on the first isolation layer, and a first high-k dielectric layer having a first height and disposed on the second isolation layer. The structure further includes a second isolation structure including a third isolation layer disposed on the substrate, a fourth isolation layer disposed on the third isolation layer, and a second high-k dielectric layer having a second height and disposed on the fourth isolation layer, where the second height is less than the first height. The structure further includes a gate structure disposed on the first isolation structure, and an insulating structure disposed adjacent to the gate structure and on the second isolation structure.