Movable Shield Adjusts Edge Ring Plasma Exposure

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Solution Overview

Problem

In plasma processing of semiconductor wafers, the edge ring's consumption leads to uneven plasma distribution, causing tilt angles of etched holes to deviate from specifications, necessitating frequent replacement and affecting processing throughput.

Innovation Solution

A plasma processing apparatus with a movable shielding member that adjusts the area of the edge ring exposed to plasma, maintaining optimal plasma distribution by controlling the shielding member's position relative to the edge ring, thereby stabilizing the tilt angles of etched features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the edge ring is continuously exposed to plasma during processing, then plasma distribution uniformity is improved, but the edge ring consumption increases leading to tilt angle deviation

Engineering Contradiction:

Improvetilt angle of etched holesVSAvoidreplacement period of edge ring

Core Design Contradiction:

Manufacturing precisionVSDuration of action of stationary object

Solution Approach 1:

The patent applies the dynamics principle by making the shielding member movable rather than fixed. The shielding member can be moved in the radial direction to adjust the exposed area of the edge ring, allowing the system to adapt to different processing stages and maintain optimal plasma distribution throughout the edge ring's service life, thereby extending its replacement period while maintaining manufacturing precision.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the edge ring's exposed area by adjusting the position of the shielding member. By controlling the radial position of the shielding member, the system dynamically adjusts the plasma exposure area of the edge ring, optimizing the balance between plasma distribution uniformity and edge ring consumption rate.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If the edge ring exposed area is increased to maintain plasma distribution, then processing uniformity is improved, but edge ring consumption accelerates requiring frequent replacement

Engineering Contradiction:

Improveplasma distribution uniformityVSAvoidprocessing throughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The movable shielding member enables dynamic adjustment of the edge ring's exposed area, allowing the system to maintain optimal plasma distribution uniformity without permanently increasing the exposed area. This dynamic control prevents excessive edge ring consumption while maintaining processing quality, thereby reducing replacement frequency and improving overall processing throughput.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the exposed area parameter of the edge ring by adjusting the shielding member's radial position. This allows optimization of plasma distribution uniformity while controlling the consumption rate, preventing the need for frequent replacements that would disrupt processing throughput.

Inventive Principle:

Principle #35Parameter changes

3Duration of action of stationary object

If a fixed shielding structure is used to control plasma exposure, then edge ring consumption is reduced, but plasma distribution uniformity deteriorates

Engineering Contradiction:

Improvereplacement period of edge ringVSAvoidplasma distribution uniformity

Core Design Contradiction:

Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The patent transforms a fixed shielding structure into a movable one, allowing dynamic adjustment of the shielding position. This enables the system to optimize plasma distribution uniformity at different stages of edge ring usage, maintaining manufacturing precision while extending the replacement period through adaptive control rather than static protection.

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 solution extends the replacement period of edge rings and improves processing throughput by maintaining consistent plasma distribution and preventing excessive tilt angles in etched holes.

Implementation Method 1

The shield is capable of shielding a portion of the surface of the edge ring from plasma generated in the processing chamber

Methodology Applied

Scientific EffectShielding:

Implementation Method 2

The driver is capable of changing the area of the edge ring exposed to the plasma by moving the shield relative to the edge ring

Methodology Applied

Scientific EffectMechanical motion:

Implementation Method 3

plasma generated in the processing chamber

Methodology Applied

Scientific EffectPlasma generation: Ionisation

Data Source

PatentUS11495445B2Plasma processing apparatus and plasma processing method

Publication Date: 2022.11.08 TOKYO ELECTRON LTD

AI summary

A plasma processing apparatus includes a processing chamber where a plasma processing is performed on a workpiece, a stage, an edge ring, a shield, and a driver. The stage has a placement surface on which the workpiece is placed inside the processing chamber. The edge ring is provided around the stage so as to surround the workpiece on the placement surface. The shield is capable of shielding a portion of the surface of the edge ring from plasma generated in the processing chamber. The driver changes the area of the edge ring exposed to the plasma by moving the shield relative to the edge ring.