Low-Temperature Halogen CVD for High-Aspect-Ratio Film Deposition

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Solution Overview

Problem

Forming high-quality films at low temperatures on substrates with high aspect ratios is challenging due to the low heat-resistant temperature of processing gases containing amino ligands, which decompose at high temperatures, and the inefficiency of oxygen plasma and ozone in reaching the substrate bottom.

Innovation Solution

A technique involving loading a substrate into a process chamber, supplying H2O-containing radicals, a halogen element gas, and an oxygen or nitrogen gas, with repeated cycles to improve the adsorption of halogen-based precursors, allowing for the formation of high-quality films at low temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a processing gas including an amino ligand is used, then a film can be formed on the substrate, but the processing temperature must be lowered because the amino ligand decomposes at high temperatures

Engineering Contradiction:

Improveprocessing temperatureVSAvoidfilm quality

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the processing gas by replacing traditional amino ligand-based precursors with halogen-based precursors (such as SiCl4, SiHCl3, SiH2Cl2). This parameter change allows the processing temperature to be maintained at lower levels (below 400°C) while preventing decomposition, thereby resolving the contradiction between temperature control and film quality.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If oxygen plasma is used to provide high-energy oxidizing species, then film quality can be improved, but the plasma cannot reach the bottom of high aspect ratio structures

Engineering Contradiction:

Improvefilm qualityVSAvoidgas penetration

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical/plasma-based oxidation method with a chemical reaction method using halogen-based precursors and oxygen-containing gases. This substitution eliminates the need for plasma to physically penetrate deep into high aspect ratio structures, as the chemical reactions occur through gas-phase reactions and surface adsorption processes that are not limited by plasma penetration depth, thus resolving the contradiction between film quality and gas penetration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If ozone is used as an oxygen source, then low temperature processing is enabled, but O3 becomes inactive due to collision with walls and cannot form high-quality films

Engineering Contradiction:

Improveprocessing temperatureVSAvoidfilm quality

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent employs halogen-based precursors (such as SiCl4, SiHCl3, SiH2Cl2) that have appropriate stability at low temperatures but react readily with oxygen-containing gases to form the desired films. These precursors are consumed in the reaction process, providing a continuous supply of reactive species without requiring the sustained stability of ozone, thus resolving the contradiction between low temperature processing and film quality.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Stability of the object's composition

If the processing temperature is lowered to prevent amino ligand decomposition, then precursor stability is improved, but adsorption of the precursor on the substrate decreases

Engineering Contradiction:

Improveprecursor stabilityVSAvoidadsorption amount

Core Design Contradiction:

Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent changes the chemical nature of the precursor from amino ligand-based to halogen-based compounds. Halogen-based precursors have different adsorption characteristics that are not as strongly temperature-dependent as amino ligands. The halogen atoms provide strong bonding capability with the substrate surface, ensuring adequate adsorption even at lower temperatures, thus resolving the contradiction between precursor stability and adsorption amount.

Inventive Principle:

Principle #35Parameter changes

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 method enables the uniform adsorption of processing gases on high-aspect-ratio substrates, improving film quality and throughput by enhancing the adsorption of halogen-based precursors and maintaining high-quality film formation at low temperatures.

Implementation Method 1

improving adsorptive of a halogen-based precursor

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

supplying a processing gas including H2O-containing radicals to the substrate

Methodology Applied

Scientific EffectRadical formation:

Implementation Method 3

supplying a gas including a halogen element

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS12198929B2Method of manufacturing semiconductor device, substrate processing apparatus, and non-transitory computer-readable recording medium

Publication Date: 2025.01.14 KOKUSAI DENKI KK

AI summary

A method of processing a substrate includes: (a) providing a substrate; (b) supplying a processing gas comprising H2O-containing radicals to the substrate; (c) supplying a gas including at least one element of Si, Ti, Mo, Al, W, Hf or Zr and a halogen element to the substrate; (d) supplying a gas including one or both of an oxygen element and a nitrogen element to the substrate after (c); and (e) repeating (c) and (d).