Alternating Gas Flowrate for Uniform Plasma Active Species Delivery

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Solution Overview

Problem

In substrate processing apparatuses using plasma, it is challenging to uniformly supply active species between stacked substrates, leading to inadequate processing of the center parts, as the active species are easily deactivated during transfer and the pressure uniformity inside the process chamber hinders their entry between substrates.

Innovation Solution

A substrate processing apparatus is designed with a gas supply system that alternately supplies process gas at a first and a second flowrate greater than the first, using RF power to generate plasma between electrodes, ensuring active species are effectively introduced between substrates by varying flow velocities and pressures, thereby ensuring uniform processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the plasma generating unit is installed at a place spaced apart from the wafer, then the wafer is protected from plasma damages, but the active species is easily deactivated during transfer and it is difficult to improve the film quality and reduce the film forming time

Engineering Contradiction:

Improveplasma damage to waferVSAvoidfilm quality

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The plasma generation process is segmented into two distinct stages: a first plasma generation period with higher power to generate abundant active species, and a second plasma generation period with lower or zero power to allow active species to reach the wafer without additional generation, thus preventing plasma damage while maintaining film quality

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The plasma generating unit operates periodically with alternating high-power and low-power/zero-power phases. During the high-power phase, active species are generated; during the low-power phase, these species are transferred to the wafer surface without continuous plasma generation that would cause damage

Inventive Principle:

Principle #19Periodic action

2Manufacturing precision

If the plasma generating unit is installed at a place close to the wafer, then the film quality is improved and film forming time is reduced, but the wafer is exposed to plasma damages

Engineering Contradiction:

Improvefilm qualityVSAvoidplasma damage to wafer

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The power supplied to the plasma generating unit is dynamically adjusted between high and low/zero levels during the processing cycle, allowing the system to switch between active species generation mode and species transfer mode to simultaneously achieve high film quality and prevent plasma damage

Inventive Principle:

Principle #15Dynamics

3Quantity of substance

If process gas is supplied at a high flowrate, then the active species can enter between substrates more easily, but the pressure inside the process chamber becomes non-uniform and hinders entry between substrates

Engineering Contradiction:

Improveactive species supply between substratesVSAvoidpressure uniformity in process chamber

Core Design Contradiction:

Quantity of substanceVSStress or pressure

Solution Approach 1:

The process gas flowrate is varied periodically between high and low rates. During the high flowrate phase, active species are supplied to enter between substrates; during the low flowrate phase, pressure uniformity is restored to facilitate subsequent species entry, preventing permanent pressure non-uniformity

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The process gas flowrate is dynamically adjusted between high and low levels during the processing cycle, allowing the system to switch between active species supply mode and pressure equalization mode to simultaneously achieve good species distribution and maintain pressure uniformity

Inventive Principle:

Principle #15Dynamics

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 ensures that active species are rapidly and uniformly delivered to the center parts of substrates, improving film quality and reducing processing time, enhancing the productivity of the substrate processing apparatus.

Implementation Method 1

an RF unit configured to output predetermined RF power; an electrode configured to receive the predetermined RF power from the RF unit for exciting the process gas into a plasma state

Methodology Applied

Scientific EffectPlasma generation through radio frequency excitation: Plasma

Data Source

PatentUS8193101B2Substrate processing apparatus and semiconductor device manufacturing method for forming film

Publication Date: 2012.06.05 KOKUSAI DENKI KK

AI summary

Provided is a substrate processing apparatus. The substrate processing apparatus includes a process chamber, a gas supply system, a gas discharge system, an RF (radio frequency) unit, an electrode, and a control device. The control device controls the gas supply system, the gas discharge system, and the RF unit. While the control device controls the RF unit to apply predetermined RF power to the electrode for generating plasma, the control device controls the gas supply system to supply a process gas to the process chamber alternately at a first flowrate and at a second flowrate greater than the first flowrate.