Amorphous Silicon Hardmask Etch Resistance
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Solution Overview
Problem
Current silicon nitride spacers in semiconductor manufacturing have high wet etch rates, which limits their etching resistance and selectivity, making it necessary to develop a layer with improved etching properties for hardmask or spacer applications in smaller semiconductor structures.
Innovation Solution
A method involving the deposition of a primary silicon nitride layer followed by a substantially pure amorphous silicon layer, achieved by introducing silicon halide and nitrogen precursors in a reactor, where the energy source creates a plasma to form the primary layer and subsequent decomposition provides the amorphous silicon layer, enhancing etch resistance and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon nitride is deposited using PEALD or PECVD to form spacers or hardmasks, then the layer can be formed conformally over dense gate electrode lines, but the wet etch rate is too high resulting in insufficient etching resistance and selectivity
Solution Approach 1:
The patent applies composite materials by depositing a multi-layer structure consisting of a silicon nitride layer (formed by PEALD or PECVD) combined with one or more additional layers having different etching properties. This composite structure provides both the conformal deposition capability of silicon nitride and the improved etching resistance/selectivity of the additional layer(s), resolving the contradiction between ease of manufacture and etching performance.
Solution Approach 2:
The patent changes the compositional parameters of the deposited layer by introducing additional precursors or modifying the deposition conditions to create a layer with tailored etching characteristics. By adjusting the layer composition (e.g., silicon-to-nitrogen ratio, incorporation of other elements), the etching resistance and selectivity are improved while maintaining the benefits of the original deposition process.
2Reliability
If a layer with higher etching resistance and selectivity is required, then advanced properties must be achieved, but this may require different precursors, tools, or reaction chambers
Solution Approach 1:
The patent achieves multi-functionality by enabling a single deposition reactor to produce layers with different properties through parameter adjustments. The same equipment can deposit both the conformal silicon nitride layer and the high etching resistance layer by changing precursor flows, temperatures, or pressure conditions, eliminating the need for separate specialized equipment while achieving superior etching selectivity.
Solution Approach 2:
The patent merges multiple functions into a single deposition process by combining the formation of conformal layers and high etching resistance layers in one reactor. This integration allows sequential or simultaneous deposition of layers with complementary properties, achieving both ease of manufacture and superior etching performance without requiring multiple separate tools or chambers.
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 resulting layer exhibits improved etch resistance and selectivity, particularly in hydrofluoric acid, and can be deposited without requiring different precursors or tools, ensuring uniformity and protection of underlying layers.
Implementation Method 1
providing an energy source to create a plasma from the second precursor so that the second precursor reacts with the first precursor
Implementation Method 2
subsequently introducing the silicon halide in the reactor at a temperature causing decomposition of the silicon halide precursor to provide a substantially pure amorphous silicon layer
Implementation Method 3
The layer comprising the primary layer comprising silicon and second precursor and a substantially pure amorphous silicon layer on top may have a an improved etch rate in hydro fluoride HF
Data Source
AI summary
The invention relates to depositing a layer on a substrate in a reactor, by:introducing a first precursor comprising a silicon halide in the reactor;introducing a second precursor in the reactor;providing an energy source to create a plasma from the second precursor so that the second precursor reacts with the first precursor until a primary layer comprising silicon and second precursor of a desired thickness is formed;stop introducing the second precursor; and,subsequently introducing the silicon halide in the reactor at a temperature causing decomposition of the silicon halide precursor to provide a substantially pure amorphous silicon layer on top of the primary layer.