Substrate Processing Apparatus Gas Flow Control for Film Thickness Uniformity

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Solution Overview

Problem

In semiconductor device manufacturing, film thickness variations occur when forming films on substrates stacked vertically due to uneven gas distribution and pressure management in process chambers.

Innovation Solution

A method involving sequential inert gas flow rates and precursor gas management within a process chamber, including stopping evacuation, supplying inert gas to push precursor gas uniformly, and controlled evacuation to ensure consistent film deposition across substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If substrates are stacked vertically in a process chamber for film formation, then productivity is improved by processing multiple substrates simultaneously, but film thickness uniformity deteriorates due to uneven gas distribution across different substrate positions

Engineering Contradiction:

ImprovethroughputVSAvoidfilm thickness uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The gas supply process is segmented into multiple stages: initial inert gas supply, precursor gas supply with evacuation pause, and final inert gas supply with evacuation. This segmentation allows different regions of the process chamber to receive gas at different times, ensuring uniform precursor distribution across vertically stacked substrates and eliminating film thickness variations while maintaining high throughput

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Evacuation is paused during the precursor gas supply stage to allow precursors to accumulate and distribute uniformly throughout the process chamber before film deposition begins. This preliminary accumulation action ensures that all substrates, regardless of vertical position, receive equivalent precursor exposure, resolving the uniformity issue while processing multiple substrates simultaneously

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If evacuation is continuously performed during gas supply, then gas distribution uniformity is improved, but precursor gas accumulation deteriorates leading to insufficient film deposition

Engineering Contradiction:

Improvegas distribution uniformityVSAvoidprecursor gas accumulation

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The evacuation system operates periodically rather than continuously: evacuation runs during inert gas supply phases to maintain uniform gas distribution, then pauses during precursor gas supply to allow precursor accumulation. This periodic alternation between evacuation and accumulation phases ensures both uniform gas distribution and sufficient precursor quantity for complete film deposition across all substrates

Inventive Principle:

Principle #19Periodic action

3Manufacturing precision

If inert gas flow rate is increased to improve gas distribution, then mixing efficiency is improved, but precursor gas concentration deteriorates due to excessive dilution

Engineering Contradiction:

Improvegas mixing efficiencyVSAvoidprecursor gas concentration

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

Inert gas is supplied in excess during initial and final stages to ensure thorough mixing and uniform distribution, but the precursor gas supply stage operates with reduced or paused inert gas flow to prevent excessive dilution. This partial application of high flow rates at appropriate stages achieves both mixing efficiency and maintains sufficient precursor concentration for effective film deposition

Inventive Principle:

Principle #16Partial or excessive action

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 technique effectively suppresses inter-substrate variations in film thickness by ensuring uniform gas distribution and pressure control, resulting in consistent film formation across vertically stacked substrates.

Implementation Method 1

supplying an inert gas at a first inert gas flow rate from a first nozzle into the process chamber

Methodology Applied

Scientific EffectGas flow: Convection

Implementation Method 2

supplying the inert gas at the first inert gas flow rate from the first nozzle into the process chamber in a state in which the process chamber is evacuated

Methodology Applied

Scientific EffectEvacuation: Vacuum

Implementation Method 3

supplying a precursor gas stored in a reservoir part from the first nozzle into the process chamber

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS10640869B2Method of manufacturing semiconductor device, substrate processing apparatus, and recording medium

Publication Date: 2020.05.05 KOKUSAI DENKI KK

AI summary

A method of manufacturing a semiconductor device, includes: supplying precursor gas into process chamber in which plural substrates are accommodated by sequentially performing: supplying inert gas at first inert gas flow rate from first nozzle into the process chamber; supplying the inert gas at second inert gas flow rate higher than the first inert gas flow rate from the first nozzle into the process chamber while supplying precursor gas from the first nozzle into the process chamber; and supplying the inert gas at the first inert gas flow rate from the first nozzle into the process chamber while the process chamber is evacuated from an upstream side of flow of the precursor gas; stopping supply of the precursor gas; removing the precursor gas remaining in the process chamber; supplying reaction gas from a second nozzle into the process chamber; and removing the reaction gas remaining in the process chamber.