Silicon Nitride Film Deposition With Helium-Rich Plasma Uniformity
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Solution Overview
Problem
In plasma-enhanced atomic layer deposition (PEALD) processes for silicon nitride (SixNy) film deposition, there is a challenge in achieving uniform film quality across large substrate areas, particularly in difficult-to-reach areas where the plasma treatment is less effective.
Innovation Solution
The method involves exposing a semiconductor substrate to a silicon-containing precursor and then to plasmas produced from specific gas mixtures. The first plasma is generated from a helium (He) and nitrogen (N2) gas mixture with a helium:nitrogen ratio ranging from 20:1 to 1000:1, and the second plasma includes helium, nitrogen, and ammonia (NH3). This sequence helps deliver a higher flux of reactive species, such as atomic nitrogen, to improve film quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional plasma-enhanced ALD (PEALD) is used for silicon nitride deposition, then the process can be performed at low temperatures (≤600°C), but the film quality varies in difficult-to-reach areas where plasma treatment is less effective
Solution Approach 1:
The patent changes the plasma gas composition parameters by using helium-rich mixtures (95-99.99% He with 0.01-5% N2) instead of conventional nitrogen-based plasmas. This parameter change increases the flux of reactive nitrogen species while maintaining low deposition temperatures, thereby improving film quality uniformity across the substrate surface including difficult-to-reach areas.
Solution Approach 2:
The patent employs a composite plasma approach by combining helium and nitrogen gases to create a plasma environment that delivers enhanced reactive species flux. The helium-nitrogen plasma mixture creates conditions that improve nitrogen delivery to the substrate, resulting in more uniform silicon nitride film quality across varying substrate geometries while maintaining low temperature processing.
2Productivity
If the substrate area is increased to improve production capacity, then more wafers can be processed, but maintaining uniform layer thickness becomes more difficult
Solution Approach 1:
By changing the plasma gas composition to helium-rich mixtures, the patent achieves enhanced reactive species flux that improves deposition uniformity across larger substrate areas. This allows processing of more wafers or larger wafer sizes while maintaining consistent layer thickness, thereby supporting increased production yield without sacrificing manufacturing precision.
3Manufacturing precision
If more plasma reactive species are delivered to difficult-to-reach areas, then film quality improves, but the process complexity increases
Solution Approach 1:
The patent achieves improved film quality in difficult-to-reach areas by relatively简单地 changing the plasma gas composition to helium-rich mixtures. This straightforward parameter change, implemented through standard gas flow control, delivers enhanced reactive species flux without requiring complex process modifications, thereby improving film quality while minimizing process complexity.
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 results in improved film quality for silicon nitride deposits, as evidenced by reduced sidewall loss during wet etching, indicating better uniformity and adherence across the substrate surface.
Implementation Method 1
exposing the semiconductor substrate to a first plasma produced from a first gas mixture comprising helium (He) and nitrogen (N2)
Implementation Method 2
exposing the semiconductor substrate to a second plasma produced from a second gas mixture comprising helium (He), nitrogen (N2), and ammonia (NH3)
Data Source
AI summary
Methods of depositing improved quality silicon nitride (SixNy) films are disclosed. Exemplary methods include exposing a semiconductor substrate in a semiconductor processing chamber to a silicon-containing precursor, to a first plasma produced from a first gas mixture comprising helium (He) and nitrogen (N2), the first gas mixture comprising a ratio of helium:nitrogen in a range of from 20:1 to 1000:1, and exposing the semiconductor substrate to a second plasma produced from a second gas mixture comprising helium (He), nitrogen (N2), and ammonia (NH3).