Trench Oxide Sidewall Profiling for Precise Gate Filling
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Solution Overview
Problem
The challenge in semiconductor device manufacturing is achieving highly controllable dimensional and structural parameters for oxide layers on trench sidewalls, particularly in terms of thickness, shape, and uniformity, to ensure compliance with device specifications and minimize scrap rates in high integration density devices.
Innovation Solution
A method involving ion implantation to damage a portion of the oxide layer on the sidewalls of a trench, followed by etching with a controlled etching mask to create a transitional section with a specific inclination angle and depth, allowing for the growth of a thin oxide layer while maintaining mechanical strength, which is crucial for reliable device characteristics and manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick oxide layer is formed over the entire trench sidewall to ensure mechanical strength, then the mechanical strength is improved, but the dimensional control precision and uniformity deteriorate
Solution Approach 1:
The patent applies local quality by creating different oxide layer configurations in different regions of the trench sidewall. Specifically, a first oxide layer is formed over a first portion of the sidewall, while a second oxide layer with different thickness or composition is formed over a second portion. This allows the structure to have varying mechanical strength and dimensional characteristics in different locations, optimizing both strength and precision requirements simultaneously.
Solution Approach 2:
The oxide layer is segmented into multiple distinct layers (first oxide layer and second oxide layer) with different properties. This segmentation enables independent optimization of each layer's thickness and composition to meet different functional requirements - one layer provides mechanical strength while another provides dimensional control precision.
2Manufacturing precision
If the oxide layer thickness is reduced to improve dimensional control, then the manufacturing precision is improved, but the mechanical strength deteriorates
Solution Approach 1:
The patent uses composite material structure by combining different oxide layers with distinct properties. The first oxide layer and second oxide layer have different thicknesses, compositions, or material characteristics, creating a composite structure that provides both the dimensional control precision of thinner layers and the mechanical strength of thicker regions.
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 enables precise control over the oxide layer's transitional section, ensuring reliable device performance, reduced scrap rates, and compliance with manufacturing tolerances by creating a smooth, controllable surface for filling with gate electrode material, thereby enhancing the reliability and efficiency of semiconductor devices.
Implementation Method 1
At least a portion of the oxide layer at at least one of the opposing sidewalls is damaged by ion implantation
Implementation Method 2
The oxide layer is partly removed by etching the oxide layer beneath the etching mask down to an etching depth at the at least one of the opposing sidewalls by introducing an etching agent into the opening
Data Source
Figure 1A~1F
Figure 1G~2B
Figure 3A~4B
AI summary
A method of manufacturing a trench oxide in a trench for a gate structure in a semiconductor substrate is described. The method comprises generating the trench (110) in the semiconductor substrate (101); generating an oxide layer (120) over opposing sidewalls (110A, 110B) of the trench; damaging at least a portion (121) of the oxide layer by ion implantation; coating the oxide layer with an etching mask (130); generating at least one opening (131) in the etching mask adjacent to one of the opposing sidewalls; and partly removing the oxide layer by etching the oxide layer beneath the etching mask down to an etching depth (ED) at the one of the opposing sidewalls (110A) by introducing an etching agent into the opening.