Angled Sputtering Wafer Holder with Raised Outer-Ring

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Solution Overview

Problem

Conventional wafer holders in angled sputtering systems face challenges with non-uniform film deposition at the wafer edge due to edge exclusion, leading to larger than desired edge exclusion zones and contamination of the wafer backside with deposited material.

Innovation Solution

A wafer holder design featuring a wafer stage with a smaller diameter than the wafer and an outer-ring with varying inner diameters, where the upper surface of the outer-ring is above the wafer surface, creating a narrow space to minimize edge exclusion and prevent backside contamination, with adjustable components to optimize shadowing effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the masking outer-ring is lowered close to the wafer surface, then edge exclusion is minimized, but film wrapping around the wafer edge increases

Engineering Contradiction:

Improveedge exclusionVSAvoidfilm wrapping and backside contamination

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

By segmenting the outer-ring into adjustable sections, the design allows selective positioning where only necessary areas are covered close to the wafer surface. This minimizes the overall contact area, reducing film wrapping and backside contamination while maintaining effective edge exclusion control

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The adjustable outer-ring segments act as an intermediary structure that can be positioned to achieve optimal spacing. This controlled spacing prevents direct contact between the ring and wafer, serving as a mediator that reduces film wrapping while still providing the necessary masking function for edge exclusion

Inventive Principle:

Principle #24Intermediary (Mediator)

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 design reduces edge exclusion to less than 2 mm and minimizes backside contamination, ensuring uniform film deposition and preventing film wrapping around the wafer edge, meeting semiconductor industry standards for small edge exclusion.

Implementation Method 1

forming many different films on Si wafers by physical vapor deposition (PVD) is one of the common steps

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

An angled sputtering is one of the PVD techniques where the target and wafer are placed not in parallel but with an angle

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS8986522B2Angled sputtering physical vapor deposition apparatus with wafer holder and wafer holder for an angled sputtering physical vapor deposition apparatus

Publication Date: 2015.03.24 CANON ANELVA CORP

AI summary

A wafer holder including a wafer stage and a wafer stage outer-ring surrounding the wafer stage wherein the wafer stage has a diameter smaller than the diameter of a wafer loaded on the wafer stage, the wafer stage outer-ring has an inner diameter at the upper side of the outer-ring which is larger than the diameter of the wafer loaded on the wafer stage, and the upper surface of the outer-ring lies above the upper surface of the wafer loaded on the wafer stage.