Conical Deposition Chamber with HULA Substrate Holder

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Solution Overview

Problem

Existing electron beam coaters for semi-conductor processing are inefficient in achieving orthogonal deposition necessary for lift-off applications, are sensitive to process variations, and result in significant waste of evaporant material on surfaces other than the target wafers.

Innovation Solution

The use of a conical-shaped deposition chamber combined with a High Uniformity Lift-off Assembly (HULA) substrate holder and a unique uniformity mask configuration optimizes collection efficiency, reducing waste and improving throughput by up to 40% and pumpdown times by up to 50%, while maintaining precise and uniform coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional box-shaped deposition chamber is used, then the system can accommodate standard equipment, but the pumping efficiency is poor and pumpdown times are long

Engineering Contradiction:

Improvepumping efficiencyVSAvoidpumpdown times

Core Design Contradiction:

Loss of energyVSLoss of time

Solution Approach 1:

The patent applies this principle by changing the chamber geometry from a conventional box shape to a conical shape. The conical configuration with its curved surfaces and tapered structure reduces the chamber volume and optimizes the pumping characteristics, enabling faster pumpdown times and improved pumping efficiency while maintaining the same functional capabilities.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Loss of substance

If a single-dome vapor deposition system is used, then the equipment structure is simple, but there is significant waste of evaporant material on surfaces other than target wafers

Engineering Contradiction:

Improveevaporant material wasteVSAvoidcollection efficiency

Core Design Contradiction:

Loss of substanceVSProductivity

Solution Approach 1:

The patent divides the single-dome structure into multiple separate dome assemblies arranged in a circular pattern around the evaporation source. Each dome can independently hold wafers and can be rotated to optimal positions during deposition. This segmentation allows better control over where material deposits, reducing waste on non-target surfaces while increasing overall collection efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic rotation capability to each dome assembly, allowing them to rotate independently around the evaporation source. This dynamic adjustment enables real-time optimization of deposition geometry, directing evaporant material precisely toward target wafers and minimizing waste on surrounding surfaces throughout the deposition process.

Inventive Principle:

Principle #15Dynamics

3Productivity

If multiple wafers are coated by a single source in a conventional system, then throughput is limited, but complex machinery with specific setups for specific power levels and materials is required

Engineering Contradiction:

ImprovethroughputVSAvoidmachinery complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent designs a universal multi-dome system where each dome assembly can accommodate multiple wafers and can be rotated to different angular positions. The system uses a single evaporation source that can service all domes simultaneously, eliminating the need for multiple separate deposition systems or complex reconfiguration machinery when coating different numbers or types of wafers.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs independent rotation mechanisms for each dome assembly, allowing dynamic repositioning of wafers during the deposition process. This dynamic capability enables a single source to efficiently coat multiple wafers on multiple domes without requiring complex mechanical reconfiguration, thereby increasing throughput while maintaining relatively simple machinery architecture.

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 configuration enhances collection efficiency, reduces material waste, and increases throughput by ensuring a higher percentage of evaporated material is deposited on wafers, with improved pumping efficiency and reduced operational costs.

Implementation Method 1

physical vapor deposition onto substrates

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

electron beam evaporation is commonly used to coat wafers with a thin metallic layer

Methodology Applied

Scientific EffectElectron beam evaporation: Electron Beam

Data Source

PatentUS8926755B2Lift-off deposition system featuring a density optimized HULA substrate holder in a conical deposition chamber

Publication Date: 2015.01.06 FERROTEC (USA) CORP

AI summary

A vapor deposition device using a lift-off process includes an evaporation source, a support frame mounted for rotation about a first axis that passes through the evaporation source, a central dome-shaped wafer holder mounted to the support frame wherein a centerpoint of the central dome-shaped wafer holder is aligned with the first axis, an orbital dome-shaped wafer holder mounted to the support frame in a position offset from the first axis and rotatable about a second axis that passes through a centerpoint of the orbital dome-shaped wafer holder and the evaporation source, and a plurality of wafer positions on the central dome-shaped wafer holder and the orbital dome-shaped wafer holder where each of the wafer positions are offset from the first axis and the second axis.