TiN Spacer Film Formation for Uniform Narrow-Linewidth Patterning
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Solution Overview
Problem
In semiconductor manufacturing, the thin SiO2 spacer films used in double patterning processes suffer from mechanical weakness and bending, while TiN films exhibit non-uniform quality due to the Critical Dimension effect, leading to inconsistent film composition and etch rates, especially at narrow line widths below 40 nm.
Innovation Solution
A method for forming a TiN spacer film with uniform composition involves sequentially and alternately supplying titanium and nitrogen gases activated by RF power, with a hydrogen-containing gas used for post-treatment to remove residual carbon and ensure stoichiometric TiN formation across the patterned structure, maintaining uniformity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If SiO2 spacer film is formed by PEALD at low temperature, then the film formation process is simple and low cost, but the film has reduced mechanical strength and bends when thickness is reduced
Solution Approach 1:
The patent uses a composite structure consisting of a SiO2 spacer film and an additional TiN film layer. The SiO2 provides the base spacer function while the TiN film reinforces the structure to prevent bending. This composite approach combines the advantages of low-temperature formation (SiO2) with high mechanical strength (TiN), resolving the contradiction between ease of manufacture and mechanical strength.
2Strength
If TiN film is formed to improve mechanical strength, then the film has high mechanical strength and resists bending, but the film composition becomes non-uniform due to Critical Dimension effect at narrow line widths
Solution Approach 1:
The patent employs a two-stage deposition process with controlled parameter changes. First, a SiO2 film is deposited under specific conditions, then a TiN film is deposited with adjusted parameters (different gas flows, temperatures, and deposition rates). This parameter optimization ensures uniform film composition even at narrow line widths below 40 nm, while maintaining the high mechanical strength provided by the TiN layer.
Solution Approach 2:
The SiO2 film is formed first as a preliminary layer that provides a uniform base structure. This preliminary action creates a stable foundation that helps ensure subsequent TiN film deposition occurs uniformly across the substrate, including at narrow line widths. The sequence of operations (SiO2 first, then TiN) is critical to achieving both uniformity and mechanical strength.
3Manufacturing precision
If spacer film thickness is reduced for narrow line widths, then the pattern resolution is improved, but the film bends due to reduced mechanical strength
Solution Approach 1:
The patent uses a composite structure where a thin SiO2 spacer film (optimized for narrow line width resolution) is combined with a TiN film layer (optimized for mechanical strength). This allows the spacer film thickness to be reduced for better pattern resolution while the TiN layer compensates for the reduced mechanical strength, preventing bending.
4Device complexity
If conventional PEALD method is used for TiN film formation, then the process is simple, but the film composition is non-uniform and etch rates vary across the patterned structure
Solution Approach 1:
The patent employs optimized deposition parameters including controlled gas flow rates (specific ratios of nitrogen, hydrogen, and other reactant gases), controlled deposition temperature, and staged deposition sequences. These parameter changes ensure uniform TiN film composition across the entire patterned structure, including variations in line width, while maintaining a relatively simple overall process flow that builds upon conventional PEALD methodology.
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 method achieves a TiN spacer film with uniform quality and mechanical strength, preventing bending and ensuring consistent film composition even at narrow line widths, thereby improving the yield and uniformity of semiconductor devices.
Implementation Method 1
the second gas and the treatment gases are activated by RF power
Implementation Method 2
a method for forming a TiN spacer film comprises a step of forming a film on a patterned structure
Implementation Method 3
wherein a hydrogen-containing gas is used for post-treatment
Data Source
AI summary
Provided is a method of forming a TiN spacer film on the patterned structure comprising a step of loading a substrate onto a chamber, a step of forming a film on the substrate; a step of post treatment to the film; and a step of unloading the substrate, wherein the step of forming the film on the substrate comprises supplying a first gas and a second gas sequentially and alternately, wherein the step of post treating to the film comprises supplying treatment gas to the substrate, wherein the second gas and the treatment gas are activated by RF power.