Silicon Nitride Seed Layer Deposition for Tungsten Resistivity Control
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Solution Overview
Problem
Existing methods for forming silicon oxide films on tungsten films using atomic layer deposition (ALD) face challenges in suppressing the oxidation of the tungsten film, leading to increased resistivity due to silicidation when high temperatures are used for forming subsequent silicon oxide layers.
Innovation Solution
A film deposition method involving the formation of a seed layer at a low temperature followed by a bulk layer at a higher temperature, using specific silicon-containing gases and nitriding gases, to prevent silicidation and maintain low resistivity in the metal film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature is used for forming silicon oxide film, then film formation quality is improved, but tungsten film oxidation occurs leading to increased resistivity
Solution Approach 1:
The film formation process is divided into two distinct stages: a first stage at low temperature (25-350°C) to form an initial silicon oxide layer, and a second stage at medium to high temperature (500-750°C) to form the bulk silicon oxide film. This segmentation allows each stage to operate under optimal conditions without causing harmful oxidation of the tungsten film.
Solution Approach 2:
A preliminary silicon oxide film is formed at low temperature before the high temperature processing. This preliminary layer acts as a protective barrier that prevents oxygen from reaching and oxidizing the tungsten film during subsequent high temperature film formation.
2Manufacturing precision
If high temperature is used for forming silicon oxide film, then film density is improved, but silicidation occurs increasing metal film resistivity
Solution Approach 1:
The deposition process is segmented into low temperature and high temperature stages. The low temperature stage forms a controlled initial layer, while the high temperature stage completes the film formation with proper density, preventing uncontrolled silicidation reactions.
Solution Approach 2:
The substrate temperature parameter is changed between stages: maintained at low temperature (25-350°C) during initial deposition, then increased to medium-high temperature (500-750°C) for bulk film formation. This parameter control prevents silicidation while achieving desired film density.
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 effectively suppresses the increase in resistivity of the metal film by controlling the temperature stages and gas alternation, ensuring high-quality film formation without significant silicidation.
Implementation Method 1
forming a seed layer containing silicon atoms and nitrogen atoms on a metal film of a substrate by supplying a first silicon-containing gas and a first nitriding gas to the substrate
Implementation Method 2
supplying a second silicon-containing gas and a second nitriding gas to the substrate in a state where the substrate is maintained at a second temperature greater than the first temperature
Data Source
AI summary
A film deposition method includes forming a seed layer containing silicon atoms and nitrogen atoms on a metal film of a substrate by supplying a first silicon-containing gas and a first nitriding gas to the substrate in a state where the substrate is maintained at a first temperature; and forming a bulk layer containing silicon atoms and nitrogen atoms on the seed layer by supplying a second silicon-containing gas and a second nitriding gas to the substrate in a state where the substrate is maintained at a second temperature greater than the first temperature.