Gate Dielectric Formation Sequence for Semiconductor Substrate Stress
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Solution Overview
Problem
Prior semiconductor device fabrication processes often result in surface stress and topography distortion of the semiconductor substrate due to thermal treatments, leading to dislocation of the dielectric layer and alignment issues, which can cause device failure.
Innovation Solution
A method where a first gate dielectric layer is formed on the semiconductor substrate before any thermal treatments, protected by a protection layer and a hard mask layer, and an isolation structure is formed to divide the substrate into active regions, ensuring the dielectric layer is not distorted by subsequent processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If thermal treatments are conducted on the semiconductor substrate before forming the dielectric layer, then the semiconductor substrate undergoes stress relief and topography adjustment, but the surface stress and topography become distorted causing dislocation of the dielectric layer
Solution Approach 1:
The dielectric layer is formed on the semiconductor substrate before any thermal treatments are conducted. This preliminary action ensures that the dielectric layer is deposited on a substrate with stable surface stress and topography, avoiding subsequent distortion and alignment issues that would occur if thermal treatments were performed first.
2Productivity
If the dielectric layer is formed after thermal treatments, then the thermal processes are completed first, but the dielectric layer becomes misaligned due to substrate distortion
Solution Approach 1:
The dielectric layer formation is performed as a preliminary step before thermal treatments. This sequence reversal maintains manufacturing precision by ensuring the dielectric layer is deposited on an undistorted substrate, while still allowing all necessary thermal processes to be completed in the overall fabrication flow.
3Stability of the object's composition
If thermal treatments are performed before dielectric layer formation, then stress relief is achieved, but concave regions form at STI interfaces causing dielectric layer thinning
Solution Approach 1:
The dielectric layer is formed before thermal treatments that create concave regions at STI interfaces. By performing the dielectric deposition first, the layer is deposited with uniform thickness on a flat substrate surface, avoiding the thinning effect that would occur if deposition were performed after thermal-induced concave formation.
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, an isolation structure; a first gate dielectric layer and a first gate electrode. The isolation structure is formed in the semiconductor substrate to divide the semiconductor substrate at least into a first active region and a second active region. The first gate dielectric layer is disposed on the first active region, and has a plane top surface contacting to a sidewall of the isolation structure and forming an acute angle therewith. The first gate electrode stacked on the plane top surface.