Halogenated Silicon Precursor ALD for SiCN Film Control
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Solution Overview
Problem
Current atomic layer deposition (ALD) methods for silicon nitride films lack control over dielectric constants and etch rates, which are critical for advanced semiconductor applications, particularly as device nodes shrink below 45 nm, and existing silicon nitride films degrade thermally due to terminal carbon-hydrogen bonding.
Innovation Solution
The method involves using halogenated silicon precursors such as halogenated silane, carbosilane, aminosilane, or carbo-sillyl amine, combined with nitrogen-containing plasmas or precursors, and densification plasmas to deposit silicon carbon nitride (SiCN) films, allowing for tailored bonding configurations and improved thermal stability, dielectric properties, and reduced etch rates by incorporating Si—C and Si—N bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional silicon nitride films are deposited using standard ALD methods, then the films can be formed with controlled thickness, but the dielectric constants and etch rates cannot be adequately controlled
Solution Approach 1:
The patent changes the chemical parameters of the deposition process by using halogenated silicon precursors (such as SiHCl3, SiH2Cl2, SiHCl3) instead of conventional precursors. This parameter change enables precise control over dielectric constants (k values from 3.8 to 6.5) and etch rates by adjusting precursor ratios, deposition temperature, and plasma conditions during ALD processing
Solution Approach 2:
The patent creates composite silicon carbon nitride films with tailored compositions by combining silicon, carbon, and nitrogen in specific ratios. The films have composite bonding structures (Si—C, Si—N, C—N bonds) that provide simultaneous control over dielectric properties and etch resistance, achieving properties that cannot be obtained with conventional silicon nitride films
2Reliability
If standard silicon nitride films are used, then the films provide basic dielectric properties, but they degrade thermally due to terminal carbon-hydrogen bonding
Solution Approach 1:
The patent removes the harmful terminal carbon-hydrogen bonding from the film structure by using halogenated precursors that form Si—C and Si—N bonds without terminal C—H groups. The deposition process extracts unwanted C—H bonding through plasma treatment and controlled reaction conditions, leaving only thermally stable bonding configurations
Solution Approach 2:
The patent changes the bonding parameters by controlling deposition temperature, precursor exposure, and plasma treatment to favor formation of thermally stable Si—C and Si—N bonds over unstable C—H bonds. This parameter control ensures the films maintain their composition and properties after thermal annealing
3Object-affected harmful factors
If conventional ALD processes are used for silicon nitride, then the process is simple and well-established, but the films lack resistance to hydrofluoric acid etching
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating carbon into the silicon nitride matrix through halogenated silicon precursors. This composition change provides inherent resistance to hydrofluoric acid etching while maintaining compatibility with standard ALD equipment and processes
Solution Approach 2:
The patent creates composite SiCN films that combine the benefits of silicon nitride (dielectric properties) with carbon-containing phases (HF etch resistance). The composite structure provides dual functionality without requiring complex multi-step processes
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 SiCN films exhibit lower dielectric constants, improved breakdown voltage, and resistance to hydrofluoric acid etching, enabling conformal coverage and stable performance even after thermal anneal, suitable for spacer and etch-stop layer applications in semiconductor devices.
Implementation Method 1
atomic layer deposition processes for the deposition films comprising silicon, carbon and nitrogen
Implementation Method 2
exposing the substrate to a nitrogen-containing plasma
Data Source
AI summary
Provided are methods for the deposition of films comprising SiCN. Certain methods involve exposing a substrate surface to a silicon precursor, wherein the silicon precursor is halogenated with Cl, Br or I, and the silicon precursor comprises a halogenated silane, a halogenated carbosilane, an halogenated aminosilane or a halogenated carbo-sillyl amine. Then, the substrate surface can be exposed to a nitrogen-containing plasma or a nitrogen precursor and densification plasma.