Off-axis Lift-and-Rotation Unit for Deposition Film Uniformity

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Solution Overview

Problem

Non-uniformity in the thickness of deposited films in semiconductor manufacturing can lead to variations in device parameters and interconnect structures, affecting subsequent processing steps like lithographic patterning and etching.

Innovation Solution

A deposition chamber equipped with an off-axis lift-and-rotation unit, featuring an electrostatic chuck with arc-shaped holes and lift pins that protrude and retract, allowing for substrate lifting and rotation during film deposition, which helps in achieving uniform film thickness by averaging out plasma, gas flow, and temperature distribution asymmetries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional deposition chamber without substrate rotation is used, then the deposition process is simple and fast, but the film thickness uniformity across the substrate deteriorates

Engineering Contradiction:

Improvefilm thickness uniformityVSAvoiddeposition chamber structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a lift-and-rotation unit that enables dynamic substrate rotation during deposition. The substrate is lifted from the electrostatic chuck and rotated to a new angular position before being placed back, creating dynamic movement that averages out plasma, gas flow, and temperature distribution asymmetries to achieve uniform film thickness

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The deposition process is segmented into multiple steps: initial deposition, substrate lifting, rotation, repositioning, and continued deposition. This segmentation allows the substrate to be repositioned at different angular orientations, ensuring that each region of the substrate receives equivalent cumulative exposure to the deposition flux from different angles

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If the substrate is rotated during deposition, then film thickness uniformity is improved, but the deposition time increases

Engineering Contradiction:

Improvefilm thickness uniformityVSAvoiddeposition cycle time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The substrate is rotated by a specific angle (e.g., 180 degrees) rather than completing a full 360-degree rotation. This partial rotation is sufficient to reposition regions of the substrate that were in high-flux areas to low-flux areas and vice versa, achieving thickness uniformity without the time penalty of a complete rotation

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The deposition process employs periodic substrate repositioning at intermediate stages rather than continuous rotation. The substrate is lifted, rotated to a new angular position, and placed back repeatedly throughout the deposition sequence, creating periodic action that maintains uniformity while minimizing interruption to the overall deposition timeline

Inventive Principle:

Principle #19Periodic action

3Measurement precision

If lift pins with arc-shaped holes are used for substrate handling, then substrate rotation precision is improved, but the electrostatic chuck structure becomes more complex

Engineering Contradiction:

Improvesubstrate rotation precisionVSAvoidelectrostatic chuck structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs arc-shaped holes in the electrostatic chuck and corresponds them with lift pins that have complementary curved surfaces. This curved geometry enables precise rotational positioning of the substrate by guiding it along a defined arc path, ensuring accurate angular placement while the chuck itself remains structurally simple

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

The solution effectively reduces thickness variations across the substrate, enhancing film uniformity and improving the consistency of semiconductor device parameters by rotating the substrate between deposition steps.

Implementation Method 1

an electrostatic chuck having a flat top surface and located within a vacuum enclosure

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Implementation Method 2

depositing a first film portion on the substrate... depositing a second film portion on the substrate

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 3

A method of depositing a film in a deposition chamber

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS11598005B2Deposition apparatus including an off-axis lift-and-rotation unit and methods for operating the same

Publication Date: 2023.03.07 SANDISK TECHNOLOGIES LLC

AI summary

A deposition chamber includes a vacuum enclosure, an electrostatic chuck having a flat top surface located within a vacuum enclosure, a lift-and-rotation unit extending through or laterally surrounding the electrostatic chuck at a position that is laterally offset from a vertical axis passing through a geometrical center of the electrostatic chuck, a gas supply manifold configured to provide influx of gas into the vacuum enclosure, and a pumping port connected to the vacuum enclosure.