Cyclic Deposition Sidewall Coverage Control
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Solution Overview
Problem
Existing methods of depositing dielectric films using plasma-enhanced atomic layer deposition (PE-ALD) face challenges in achieving uniform thickness on semiconductor substrates with recess patterns, particularly due to ion collisions affecting sidewall reactions, leading to thinner films on sidewalls compared to top surfaces.
Innovation Solution
A method involving cyclic deposition using a Si-containing precursor and reactant gas, with an additional pulse of RF power applied in the presence of a rare gas and treatment gas, to enhance sidewall coverage by controlling the duration and ratio of these steps, resulting in a dielectric film with Si—C bonds and/or Si—N bonds, achieving a sidewall coverage ratio of over 85%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nitration reaction is conducted in plasma atmosphere on sidewalls, then dielectric film is formed, but the reaction rate on sidewalls is low compared to top surface due to ion collision interference
Solution Approach 1:
The patent applies preliminary action by performing plasma treatment of the sidewall surface before introducing the precursor. This pre-treatment step activates the sidewall surface, removes contaminants, and creates reactive sites that enhance the subsequent nitration reaction. By preparing the sidewall surface in advance, the reaction rate is significantly improved compared to direct deposition without preliminary plasma activation.
Solution Approach 2:
The patent uses plasma as an intermediary to facilitate the nitration reaction on sidewalls. The plasma generates reactive species and activates the sidewall surface, acting as a mediator that enhances the interaction between the precursor and the sidewall. This intermediary plasma treatment overcomes the low reaction rate caused by ion collision interference, enabling more efficient dielectric film formation on sidewalls.
2Manufacturing precision
If cyclic deposition is conducted to form dielectric film, then conformal coating is achieved, but additional process steps are required to control sidewall coverage
Solution Approach 1:
The patent applies universality by designing a cyclic deposition process where a single integrated process performs multiple functions: it achieves conformal coating, controls sidewall coverage, and ensures uniform film thickness. The cyclic process combines plasma treatment and precursor exposure in a unified sequence that simultaneously accomplishes surface activation, material deposition, and thickness control, reducing the need for separate process steps.
Solution Approach 2:
The patent employs feedback by monitoring film thickness and sidewall coverage during the cyclic deposition process and adjusting process parameters accordingly. Real-time or post-process measurement data is used to optimize plasma power, precursor flow rates, and cycle timing to achieve the desired sidewall coverage and conformality. This feedback mechanism allows for precise control of film properties while maintaining process efficiency.
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 effectively improves the step coverage and conformality of dielectric films on semiconductor substrates, ensuring a uniform thickness on both sidewalls and top surfaces, thereby enhancing the reliability and performance of semiconductor devices.
Implementation Method 1
conducting one or more cycles of cyclic deposition in a reaction space wherein a semiconductor substrate is placed, using a Si-containing precursor and a reactant gas
Implementation Method 2
PE-ALD is a deposition technology of dielectric films using chemisorption of precursors
Implementation Method 3
applying a pulse of RF power to the reaction space while supplying a rare gas and a treatment gas
Implementation Method 4
applying a pulse of RF power to the reaction space
Data Source
AI summary
A method of forming a dielectric film having Si—C bonds and/or Si—N bonds on a semiconductor substrate by cyclic deposition, includes: (i) conducting one or more cycles of cyclic deposition in a reaction space wherein a semiconductor substrate is placed, using a Si-containing precursor and a reactant gas; and (ii) before or after step (i), applying a pulse of RF power to the reaction space while supplying a rare gas and a treatment gas without supplying a Si-containing precursor, whereby a dielectric film having Si—C bonds and/or Si—N bonds is formed on the semiconductor substrate.