Concave Substrate Film Deposition for Better Step Coverage
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Solution Overview
Problem
In semiconductor device manufacturing, achieving improved step coverage performance on substrates with deep concave structures is challenging due to the difficulty in evenly supplying source gases, leading to excessive gas supply to the upper portions and inadequate supply to the lower portions, which affects film formation uniformity and quality.
Innovation Solution
A method involving the rapid initial supply of a source gas at a rate faster than its adsorption rate to the substrate's surface, followed by a purge to remove reaction by-products, and then a slower continuous supply to optimize gas distribution and adsorption across the concave structure, ensuring better film coverage and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the source gas supply rate is increased to improve adsorption at the lower portion, then step coverage is enhanced, but gas accumulates excessively in the upper portion
Solution Approach 1:
The purge gas, which initially serves to remove excess source gas and reaction by-products (a potentially wasteful action), is converted into a beneficial step by using it to clean the concave structure before film deposition. This ensures better gas distribution and prevents harmful accumulation while improving overall process efficiency.
Solution Approach 2:
The gas supply follows a periodic pattern: initial high-rate supply, followed by purge phase, then controlled continuous supply. This periodic variation in gas flow rate prevents continuous accumulation in the upper portion while ensuring adequate supply to the lower portion during critical deposition phases.
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 enhances the step coverage performance by ensuring sufficient gas reaches the lower portions of the concave structures while minimizing excess gas on the upper portions, thereby improving film thickness uniformity and reducing void formation.
Implementation Method 1
supplying a source gas to a concave structure of a substrate provided with an adsorption site on a surface thereof at a rate faster than an adsorption rate at which a precursor of the source gas is adsorbed to the adsorption site
Implementation Method 2
supplying a purge gas to the concave structure
Data Source
AI summary
It is possible to improve a step coverage performance of a film formed on a substrate provided with a concave structure. There is provided a technique that includes: (a) supplying a source gas to a concave structure of a substrate provided with an adsorption site on a surface thereof at a rate faster than an adsorption rate at which a precursor of the source gas is adsorbed to the adsorption site; (b) supplying a purge gas to the concave structure; and (c) supplying the source gas to the concave structure at a rate slower than the adsorption rate.