Pulsed Bias ESC Cleaning for Polymer Removal

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing in-situ chamber cleaning processes for plasma processing chambers face challenges in effectively removing polymer byproducts from the confined geometry between the electrostatic chuck (ESC) sidewall and the insert ring, often resulting in damage to the ESC surface due to high ion energy and requiring protective coatings that increase processing time and complexity.

Innovation Solution

A method involving a high pressure cleaning process, followed by a first low pressure cleaning process, and a second low pressure cleaning process with a pulsed bias is used to target and remove polymer byproducts from specific regions of the chamber, including the ESC sidewall, utilizing optimized source gases and pressures to minimize damage and extend ESC lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a constantly high DC bias is applied to the ESC to drive cleaning species into the gap between the ESC sidewall and the insert ring, then the cleaning effectiveness is improved, but the ion energy becomes high enough to damage the exposed ESC surface

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidESC surface damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies periodic pulsed DC bias to the ESC during the cleaning process. The bias is applied in pulses rather than continuously, allowing cleaning species to be driven into the gap between the ESC sidewall and insert ring during the pulse periods, while preventing excessive ion energy accumulation that would damage the ESC surface during non-pulse periods. This periodic action resolves the contradiction by providing intermittent cleaning enhancement without continuous surface damage.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent dynamically adjusts the DC bias parameter from a constant high value to a time-varying pulsed signal. By making the bias dynamic rather than static, the system can optimize cleaning effectiveness during pulse periods while limiting surface damage during off-periods, thus resolving the contradiction between cleaning effectiveness and surface damage prevention.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If a protective coating is applied to the ESC surface to protect it from damage during cleaning, then the ESC surface protection is improved, but the processing time increases and additional removal steps are required

Engineering Contradiction:

ImproveESC surface protectionVSAvoidprocessing time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent makes the ESC surface self-protecting by utilizing its inherent electrical properties. The pulsed bias scheme allows the ESC to naturally limit ion energy during non-pulse periods, providing self-protection without requiring external protective coatings. This eliminates the need for additional coating application and removal steps, resolving the time loss contradiction.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Instead of using expensive and time-consuming protective coatings that must be applied and removed, the patent employs a temporary pulsed bias scheme that provides transient protection during cleaning. The pulsed bias acts as a temporary, reversible protective mechanism that does not require additional materials or post-processing removal steps.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 allows for effective removal of polymer byproducts without damaging the ESC surface, ensuring repeatable plasma processes, extending the ESC's lifespan, and reducing operational costs by minimizing the need for replacement or repair.

Implementation Method 1

applying a pulsed bias

Methodology Applied

Scientific EffectPulsed electric field: Electric Field

Implementation Method 2

drive the cleaning species into the gap between the ESC sidewall and the ring

Methodology Applied

Scientific EffectIon acceleration: Ion Beam

Implementation Method 3

cleaning the plasma processing chamber with a cleaning process

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 4

high ion energy that damages the exposed ESC surface

Methodology Applied

Scientific EffectIon bombardment: Ion Beam

Implementation Method 5

electrostatic chuck (ESC) that supports the workpiece

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS10410845B2Using bias RF pulsing to effectively clean electrostatic chuck (ESC)

Publication Date: 2019.09.10 APPLIED MATERIALS INC

AI summary

Embodiments include a plasma processing method for cleaning polymer byproducts from interior surfaces of the plasma chamber. In an embodiment the plasma process may include processing a workpiece in a plasma processing chamber. Thereafter, the method may include removing the workpiece from the processing chamber. After the workpiece is removed, embodiments may include cleaning the plasma processing chamber with a cleaning process that includes a high pressure cleaning process, a first low pressure cleaning process, and a second low pressure cleaning process, wherein the second low pressure cleaning process includes applying a pulsed bias.