Dielectric Etch Tuning via Plasma Seam Treatment
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Solution Overview
Problem
The scaling down of semiconductor integrated circuits (ICs) poses challenges due to differences in etch rates of dielectric materials, particularly in Shallow Trench Isolations (STIs) and dummy fins, caused by loading effects and the presence of seams, which affect fin height and device operation.
Innovation Solution
A treatment process is applied to control etch rates by using a plasma process with a capacitively coupled plasma (CCP) source to reduce or increase the loading effect and seam-related differences, altering the etch rates of dielectric materials, thereby achieving desired fin heights for FinFETs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used on dielectric materials in STIs and dummy fins, then etching can be performed, but etch rate variations occur due to loading effects and seam presence, affecting fin height uniformity
Solution Approach 1:
The patent applies a preliminary plasma treatment process to the dielectric material surfaces before etching. This treatment modifies the surface properties and reduces the impact of seams and loading effects, thereby pre-conditioning the material to achieve more consistent etch rates and uniform fin heights during subsequent etching operations
Solution Approach 2:
The patent changes physical and chemical parameters of the dielectric material through plasma treatment, including surface composition, energy states, and material density. These parameter changes alter the etch response of the material, reducing variability caused by loading effects and seam presence, thereby improving both etch rate consistency and fin height uniformity
2Productivity
If scaling down is pursued to increase functional density, then production efficiency improves and costs decrease, but differences in etch rates due to loading effects and seams become more significant
Solution Approach 1:
The plasma treatment process modifies material parameters such as surface energy, composition, and density to compensate for the increased sensitivity to loading effects and seams that occurs at scaled-down dimensions. This enables maintaining etch rate control despite the challenges posed by smaller feature sizes
Solution Approach 2:
The patent replaces conventional mechanical/chemical etching approaches with a plasma-based treatment and etching system. This substitution provides better control over etch rates by using plasma physics to modify material properties and achieve more uniform etching, thereby maintaining manufacturing precision during scaling down
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 treatment process reduces etch rate variations and enhances etch selectivity, leading to more uniform fin heights and improved device performance by minimizing the impact of seams and loading effects, resulting in reduced loss of dummy fins and average etch depth.
Implementation Method 1
A treatment process is applied to control etch rates by using a plasma process with a capacitively coupled plasma (CCP) source
Implementation Method 2
The treating causes a species to be on the first upper surface and the second upper surface, to be in the seam, and to diffuse into the first dielectric material in the first trench and into the first dielectric material in the second trench
Data Source
AI summary
Generally, this disclosure provides examples relating to tuning etch rates of dielectric material. In an embodiment, a dielectric material is conformally deposited in first and second trenches in a substrate. Merged lateral growth fronts of the first dielectric material in the first trench form a seam in the first trench. The dielectric material is treated. The treating causes a species to be on first and second upper surfaces of the dielectric material in the first and second trenches, respectively, to be in the seam, and to diffuse into the respective dielectric material in the first and second trenches. After the treating, the respective dielectric material is etched. A ratio of an etch rate of the dielectric material in the second trench to an etch rate of the dielectric material in the first trench is altered by presence of the species in the dielectric material during the etching.