Electrostatic Chuck Wrinkle Prevention in Plasma Processing

Solution Overview

Problem

Plasma processing of thin substrates held by conveyance carriers is hindered by substrate warping due to wrinkled holding sheets, leading to abnormal discharge, temperature increases, and reduced processing yield.

Innovation Solution

A plasma processing apparatus and method that includes an electrostatic chuck mechanism with a support portion capable of elevation and lowering, applying voltage to the electrostatic chuck electrodes before contact of the holding sheet with the stage, and using ring-shaped electrodes to ensure uniform absorption and prevent wrinkling of the holding sheet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the conveyance carrier is absorbed on the stage by electrostatic chuck mechanism, then the substrate can be held stably for plasma processing, but the holding sheet may become wrinkled causing abnormal discharge and temperature increase

Engineering Contradiction:

Improvestability of substrate holdingVSAvoidwrinkling of holding sheet

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The support portion is lowered to contact and support the conveyance carrier before the electrostatic chuck mechanism is activated. This preliminary mechanical support prevents the holding sheet from wrinkling when the electrostatic force is subsequently applied, eliminating the harmful effect while maintaining the beneficial stability.

Inventive Principle:

Principle #10Preliminary action

2Length of moving object

If the holding sheet is thin to accommodate thin substrates, then substrate thickness requirements are met, but the holding sheet becomes prone to warping and wrinkling

Engineering Contradiction:

Improvethickness of holding sheetVSAvoidflatness of holding sheet

Core Design Contradiction:

Length of moving objectVSStability of the object's composition

Solution Approach 1:

The support portion acts as an intermediary mechanical support between the conveyance carrier and the stage. It provides necessary support to maintain the flatness of the thin holding sheet during the absorption process, preventing warping and wrinkling without requiring the holding sheet to be thicker.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the electrostatic chuck mechanism is activated after the conveyance carrier contacts the stage, then the absorption process is simpler, but the holding sheet becomes wrinkled reducing processing yield

Engineering Contradiction:

Improvesimplicity of absorption processVSAvoidyield of plasma processing

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The support portion is lowered to contact and support the conveyance carrier before the electrostatic chuck mechanism is activated. This preliminary mechanical support prevents the holding sheet from wrinkling when the electrostatic force is subsequently applied, eliminating the harmful effect while maintaining the beneficial stability.

Inventive Principle:

Principle #10Preliminary 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 approach enhances the yield of plasma processing by maintaining the holding sheet in an unwrinkled state during processing, ensuring uniform etching and preventing temperature and discharge issues, thereby improving the quality and consistency of the processed substrates.

Implementation Method 1

The electrostatic chuck mechanism applies a voltage to an electrostatic chuck electrode (hereinafter referred to as an ESC electrode) disposed inside the stage and causes the conveyance carrier to be absorbed on the stage by Coulomb force or Johnsen-Rahbek force that acts between the ESC electrode and the conveyance carrier.

Methodology Applied

Scientific EffectCoulomb force: Coulomb's Law

Implementation Method 2

The electrostatic chuck mechanism applies a voltage to an electrostatic chuck electrode (hereinafter referred to as an ESC electrode) disposed inside the stage and causes the conveyance carrier to be absorbed on the stage by Coulomb force or Johnsen-Rahbek force that acts between the ESC electrode and the conveyance carrier.

Methodology Applied

Scientific EffectJohnsen-Rahbek force: Johnsen-Rahbek Effect

Implementation Method 3

The stage is being cooled. By performing plasma processing in a state that the conveyance carrier is absorbed on the stage being cooled, the conveyance carrier being subjected to plasma processing can be cooled effectively.

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9570272B2Plasma processing apparatus and plasma processing method

Publication Date: 2017.02.14 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A plasma processing apparatus includes: a reaction chamber; a stage which is disposed inside the reaction chamber and on which a conveyance carrier is mountable; an electrostatic chuck mechanism including an electrode portion that is disposed inside the stage; a support portion which supports the conveyance carrier between a stage-mounted position on the stage and a transfer position that is distant from the stage upward; and an elevation mechanism which elevates and lowers the support portion relative to the stage. In a case in which the conveyance carrier is mounted on the stage by lowering the support portion, the electrostatic chuck mechanism starts applying a voltage to the electrode portion before contact of an outer circumferential portion of a holding sheet which holds the conveyance carrier to the stage.