Motorized Coil Assembly for Plasma Baseline Skew Correction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Inductively coupled plasma reactors face challenges in maintaining uniform plasma ion density across larger wafers with smaller device features, leading to baseline skew due to asymmetrical coil alignment, chamber structure, and process recipe factors.

Innovation Solution

The introduction of an adjustable coil assembly in the plasma reactor, allowing for independent alignment adjustments of inner and outer coil antennas relative to the process volume, using tilting rings and motorized mechanisms to correct plasma density distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional fixed coil antennas are used in inductively coupled plasma reactors, then the chamber structure is simple and easy to manufacture, but baseline skew occurs due to asymmetrical coil alignment and chamber structure leading to non-uniform plasma ion density across the substrate surface

Engineering Contradiction:

Improveuniformity of plasma ion densityVSAvoidcoil assembly structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements adjustable coil assemblies that can be dynamically positioned and tilted relative to the substrate. The coil mounting plate can be tilted about a first axis and the coil antenna can be tilted about a second axis, allowing dynamic adjustment to correct baseline skew and achieve uniform plasma distribution across the substrate surface.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The coil assembly is segmented into multiple independent components including the coil mounting plate, coil antenna, and tilting rings. This segmentation allows independent adjustment of each component's position and orientation, enabling precise correction of alignment asymmetries without requiring complete redesign of the entire chamber structure.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If the coil assembly is made adjustable to correct baseline skew, then plasma uniformity is improved, but the device complexity and alignment adjustment difficulty increase

Engineering Contradiction:

Improveuniformity of plasma ion densityVSAvoidalignment adjustment

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent replaces manual mechanical adjustment with motorized drive mechanisms. Motors are integrated into the tilting ring assembly to automatically position and tilt the coil antenna according to predetermined orientations, eliminating the need for complex manual alignment procedures while maintaining precise plasma uniformity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If multiple tilting rings and motorized mechanisms are added to adjust coil alignment, then baseline skew correction capability is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:

Improvebaseline skew correctionVSAvoidcoil assembly structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The tilting ring assembly serves multiple functions: it provides structural support for the coil antenna, enables tilting adjustment about two different axes, incorporates motorized positioning, and maintains electrical connections. This multi-functionality reduces the need for separate components and minimizes overall device complexity while achieving comprehensive baseline skew correction.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effectively reduces baseline skew by ensuring uniform plasma distribution across the substrate surface, improving processing results by compensating for structural and flow rate asymmetries, and adapting to different process recipes.

Implementation Method 1

Plasma reactors used to fabricate semiconductor microelectronic circuits can employ RF (radio frequency) inductively coupled fields to maintain a plasma formed from a processing gas

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A RF plasma source power supply is connected across each of the coil antennas. The power of the signal applied to the coil antenna primarily determines the plasma ion density within the chamber

Methodology Applied

Scientific EffectRF heating: Dielectric Heating

Implementation Method 3

The nitrogen radicals and/or nitrogen ions in the nitrogen plasma then diffuse and/or bombard into the silicon dioxide gate dielectric film

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS8062472B2Method of correcting baseline skew by a novel motorized source coil assembly

Publication Date: 2011.11.22 APPLIED MATERIALS INC

AI summary

The present invention generally provides apparatus and method for adjusting plasma density distribution in an inductively coupled plasma chamber. One embodiment of the present invention provides an apparatus configured for processing a substrate. The apparatus comprises a chamber body defining a process volume configured to process the substrate therein, and a coil assembly coupled to the chamber body outside the process volume, wherein the coil assembly comprises a coil mounting plate, a first coil antenna mounted on the coil mounting plate, and a coil adjusting mechanism configured to adjust the alignment of the first coil antenna relative to the process volume.