Contoured Wafer Carrier Ring for Reliable Backside Film Deposition

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Solution Overview

Problem

Conventional wafer carrier rings in semiconductor manufacturing face challenges in reliable wafer placement due to the trade-off between increasing the contact area for stability and minimizing the peripheral area for effective backside film deposition, leading to potential misplacement or tilting of wafers.

Innovation Solution

A contoured wafer carrier ring with a step design and an inclined inner sidewall is used to support the wafer, allowing for self-aligned placement and minimizing the contact area between the wafer's backside surface and the carrier ring, thereby enhancing placement reliability and reducing the area not covered by the backside film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the contact area between the wafer and the wafer carrier ring is increased to improve placement reliability, then the effective area for deposition of the backside film decreases

Engineering Contradiction:

Improvewafer placement reliabilityVSAvoideffective deposition area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The carrier ring is segmented into multiple functional zones: a peripheral support region with increased contact area for reliable wafer placement, and a central opening region that maximizes the effective deposition area. The step structure creates distinct functional segments that simultaneously achieve both goals.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional flat contact surface to a three-dimensional stepped structure. The vertical step creates additional contact area in the vertical dimension while maintaining a minimal horizontal footprint, thus improving placement reliability without sacrificing deposition area.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If the contact area between the wafer and the carrier ring is reduced to increase the effective deposition area, then misplacement or tilting of the wafer occurs

Engineering Contradiction:

Improveeffective deposition areaVSAvoidwafer placement reliability

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The carrier ring applies local quality by concentrating support function in specific localized regions (the peripheral step areas) while leaving the central region open for deposition. This localized support provides sufficient stability without compromising the overall deposition area.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If a flat carrier ring surface is used, then the manufacturing is simple, but the wafer placement precision decreases

Engineering Contradiction:

Improvecarrier ring manufacturing simplicityVSAvoidwafer placement precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The carrier ring incorporates curved or contoured step surfaces instead of sharp edges, providing a gradual transition that guides the wafer into proper alignment. This curvature improves placement precision while remaining manufacturable using standard machining techniques.

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 contoured carrier ring design improves the reliability of wafer placement while minimizing the area of the peripheral portion of the wafer that is not covered by the backside film, thus preventing misplacement and ensuring accurate processing.

Implementation Method 1

depositing a film on an exposed portion of the backside surface of the wafer

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 2

depositing a film on an exposed portion of the backside surface of the wafer

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Data Source

PatentUS20250087525A1Semiconductor device fabrication method using a deposition apparatus with a contoured wafer carrier ring

Publication Date: 2025.03.13 SANDISK TECHNOLOGIES LLC

AI summary

A method includes placing a wafer on a step of a carrier ring in a first vacuum enclosure such that a backside surface of the wafer contacts the step, depositing a film on an exposed portion of the backside surface of the wafer while the backside surface of the wafer is in contact with the step, and depositing a semiconductor device on a front side of the wafer which is opposite to the backside surface of the wafer. The carrier ring includes a bottom surface surrounding an opening in the carrier ring, an upper top surface, a lower top surface of the step, and an inner surface which connects the upper top surface and the lower top surface, and which is inclined outward at a non-zero taper angle relative to the vertical direction which perpendicular to the lower top surface of the step.