Wavy Fin Shield for PVD Chamber Deposition

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Solution Overview

Problem

Conventional physical vapor deposition (PVD) processes face challenges in maintaining high target to substrate spacing while minimizing re-sputtering of the grounded shield, leading to contamination and reduced deposition rates due to uneven voltage distribution between the target and shield.

Innovation Solution

The use of a shield with an inner wall featuring a first wavy fin configuration on the upper portion and a second wavy fin configuration on the bottom portion, increasing the surface area to 1400-1410 in², which helps in reducing the potential difference to the grounded shield and minimizing re-sputtering by maintaining a higher negative self-bias on the target.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If extremely wide body chambers are used to increase anode area and obtain higher negative self-bias on targets, then the self-bias magnitude is improved, but the footprint of the PVD chamber increases

Engineering Contradiction:

Improvenegative self-bias on targetVSAvoidfootprint of PVD chamber

Core Design Contradiction:

Stress or pressureVSArea of stationary object

Solution Approach 1:

The patent transforms the problem from a two-dimensional plane expansion (wider chamber) to a three-dimensional solution by adding vertical complexity through wavy fin configurations on the shield. This increases the effective anode surface area without expanding the chamber footprint, resolving the contradiction between achieving higher negative self-bias and maintaining a compact chamber size.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The wavy fin configurations introduce curved surfaces on the shield structure, replacing flat surfaces with undulating geometries. This curvature increases the surface area of the anode (shield) that contributes to plasma generation and negative self-bias development, allowing higher self-bias magnitudes within a smaller chamber footprint.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Productivity

If high negative self-bias is maintained on the target to increase sputtering rate, then deposition rate is improved, but re-sputtering of the shield increases causing contamination

Engineering Contradiction:

Improvedeposition rateVSAvoidre-sputtering of shield

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different wavy fin configurations to different regions of the shield (upper portion vs. lower portion), creating local variations in surface area and plasma distribution. This localized differentiation allows optimization of the plasma sheath distribution to maintain high negative self-bias on the target while reducing the electric field intensity at the shield surface, thereby minimizing re-sputtering and contamination.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

By changing the geometric parameters of the shield (introducing wavy fin configurations with specific dimensions and patterns), the patent modifies the electric field distribution and plasma density profiles. This parameter optimization enables maintaining high deposition rates through sustained negative self-bias while simultaneously reducing the conditions that lead to shield re-sputtering and contamination.

Inventive Principle:

Principle #35Parameter changes

3Stress or pressure

If the surface area of the shield is increased to reduce potential difference to grounded shield, then voltage distribution is improved, but the complexity of shield configuration increases

Engineering Contradiction:

Improvepotential difference to grounded shieldVSAvoidshield configuration

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

The shield is segmented into distinct regions (upper portion and lower portion) with different wavy fin configurations. This segmentation allows each region to be optimized for specific functions: the upper portion configuration addresses potential difference reduction, while the lower portion configuration addresses re-sputtering minimization. The modular segmented design manages complexity by dividing the shield into functional zones rather than requiring a uniformly complex structure.

Inventive Principle:

Principle #1Segmentation

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 configuration enhances deposition rates up to 10 angstroms/second while maintaining high ionization levels and reduces contamination by minimizing re-sputtering of the shield, thereby improving the overall efficiency of the PVD process.

Implementation Method 1

an RF power source to form a plasma within the chamber body

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

physical vapor deposition chamber

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS11621152B2Methods and apparatus for processing a substrate using improved shield configurations

Publication Date: 2023.04.04 APPLIED MATERIALS INC

AI summary

Methods and apparatus for processing a substrate using improved shield configurations are provided herein. For example, a process kit for use in a physical vapor deposition chamber comprises a shield comprising an inner wall comprising an upper portion having a first wavy fin configuration and a bottom portion having a second wavy fin configuration different from the first wavy fin configuration such that a surface area of the shield is about 1400 in2 to about 1410 in2.