Semiconductor Substrate Thin Film Deposition via Plasma-Activated ALD
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the inconsistency in film quality at the interface between thin films and their base due to incubation time delays and irregularities in the deposition process, which affects the reliability and performance of devices like flash memory, especially with the thinning of tunnel oxide films.
Innovation Solution
A method involving alternating cycles of processing gas supply and exhaustion in a substrate processing apparatus to form and modify thin films, using gases like hexachlorodisilane and ammonia, with plasma activation to control film thickness and quality, ensuring consistent deposition without incubation time issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a nitride layer is formed by ALD or CVD method, then an extremely uniform thin film can be formed, but a time delay (incubation time) occurs before deposition starts and irregularities are formed during nucleus forming process
Solution Approach 1:
The patent applies preliminary action by performing a surface modification treatment before the main nitride layer deposition. This treatment activates the substrate surface and prepares it for immediate film formation, eliminating the incubation period. The surface is pre-treated with specific gases or plasma to create nucleation sites, ensuring that the subsequent deposition process starts immediately without time delay and produces uniform film quality from the beginning.
2Reliability
If the film quality at the interface is different from the film quality in the film body, then charge is trapped by both the nitride layer and the interface, but this makes it impossible to exhibit superiority of the insulation trap type structure
Solution Approach 1:
The patent applies local quality by implementing a multi-layer structure with different film formation conditions for the interface region and the film body. The interface layer is formed with specific parameters (such as lower temperature or different gas flow rates) to ensure high-quality adhesion and uniform composition at the critical substrate-film interface, while the upper film body is formed with optimized parameters for the desired electrical characteristics. This localized control of film properties ensures consistent quality throughout the structure.
Solution Approach 2:
The patent segments the film formation process into distinct stages: interface layer formation and film body deposition. By dividing the continuous deposition process into separate controllable stages, each with optimized parameters, the patent ensures that the interface region achieves superior quality without compromising the overall film properties. This segmentation allows independent optimization of each region's characteristics.
3Length of moving object
If the tunnel oxide film is made thinner for micronization and low power consumption, then further micronization is realized, but reliability is reduced due to insulation breakdown and stress-induced leak current
Solution Approach 1:
The patent applies composite materials by creating a multi-layer structure consisting of the thinned tunnel oxide film combined with a nitride layer having specific electrical characteristics. This composite structure leverages the advantages of both materials: the thin tunnel oxide enables micronization and low power consumption, while the nitride layer provides charge trapping capability and insulation protection. The combination compensates for the reliability issues arising from the thin oxide, maintaining device reliability despite reduced thickness.
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 improves the film quality at the interface and controls the film quality consistently, enhancing the reliability and performance of semiconductor devices by eliminating irregularities and delays in the deposition process.
Implementation Method 1
supplying the second processing gas activated by plasma-excitation into the processing chamber
Implementation Method 2
forming a first thin film by performing a first film forming step on a surface of a substrate placed in a processing chamber
Data Source
AI summary
A first processing gas containing a first element and a second processing gas containing a second element are alternately supplied to a surface of a substrate placed in a processing chamber, to thereby form a first thin film, and a second processing gas and a third processing containing the first element and different from the first processing gas are alternately supplied, to thereby form a second thin film on the first thin film, having the same element component as that of the first thin film.