High-K Gate Dielectric Self-Protective Layer Against Etching Damage
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Solution Overview
Problem
In semiconductor manufacturing, especially in advanced process nodes, the formation of gate structures in FinFET devices is challenging due to inaccurate control of deposition and patterning processes, leading to deterioration of electrical performance and potential etching of gate dielectric layers during cleaning processes.
Innovation Solution
A self-protective layer is formed on the gate dielectric layer using a phosphoric acid-based etching solution, which reacts with metal elements in the high-k dielectric layer to create a protective metal phosphate layer, preventing further etching and ensuring the integrity of the gate dielectric layer during patterning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-k dielectric layer is used in gate structures to improve electrical performance, then device performance is enhanced, but the layer becomes susceptible to etching damage during cleaning processes
Solution Approach 1:
A protective layer is formed on the high-k dielectric layer before subsequent processing steps. This preliminary protective coating prevents etching damage during cleaning processes while allowing the high-k dielectric to maintain its electrical performance benefits.
Solution Approach 2:
The protective layer acts as an intermediary between the high-k dielectric layer and the etching environment. It provides a barrier that prevents direct contact between harmful etchants and the sensitive high-k dielectric material, thereby protecting the gate structure during manufacturing processes.
2Ease of manufacture
If deposition and patterning processes are performed to form gate structures, then device fabrication is enabled, but inaccurate control leads to deterioration of electrical performance
Solution Approach 1:
The protective layer is deposited beforehand to establish a controlled interface for subsequent patterning operations. This preliminary layer provides a more forgiving substrate that reduces variability in deposition and patterning processes, thereby improving manufacturing precision while maintaining ease of fabrication.
Solution Approach 2:
The introduction of the protective layer modifies the physical and chemical parameters of the gate stack interface. This parameter change enables more precise control over deposition rates, patterning dimensions, and overall process variability, leading to better electrical performance control.
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 self-protective layer effectively stops etching at the gate dielectric layer, maintaining its effectiveness and enhancing electrical performance by preventing damage during the formation of metal gate structures, thus improving the reliability of FinFET devices.
Implementation Method 1
A self-protective layer is formed on the gate dielectric layer using a phosphoric acid-based etching solution, which reacts with metal elements in the high-k dielectric layer to create a protective metal phosphate layer
Data Source
AI summary
Semiconductor device structures having metal gate structures with tunable work function values are provided. In one example, a first gate structure and a second gate structure formed on a substrate, wherein the first gate structure includes a first work function metal having a first material, and the second gate structure includes a second work function metal having a second material, the first material being different from the second material, wherein the first gate structure further includes a gate dielectric layer, a self-protective layer having metal phosphate, and the first work function metal on the self-protective layer.