Tubular Sputtering Target Plasma Density and Deposition Rate

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Solution Overview

Problem

Facing targets sputtering devices have low plasma density, making it difficult to achieve high deposition rates, and existing sputtering devices struggle with film formation on flat boardlike bodies.

Innovation Solution

A sputtering device with a tubular-shaped target having a rectangular cross-sectional shape, where the erosion surface faces inward, and a film formation roller with a cylindrical section made of copper, copper alloy, or aluminum alloy having a built-in flow passage to maintain flatness and control temperature during film formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If facing targets sputtering device is used, then plasma restriction is achieved, but plasma density remains low and deposition rate is insufficient

Engineering Contradiction:
Improveplasma restrictionVSAvoiddeposition rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention employs a cylindrical target with an inward-facing erosion surface, transforming the conventional flat or planar target geometry into a curved cylindrical form. This curvature concentrates plasma discharge along the cylindrical surface, increasing plasma density and sputtering particle generation while maintaining effective plasma restriction, thereby resolving the contradiction between reliable plasma confinement and sufficient deposition rate.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention transitions from a two-dimensional planar target surface to a three-dimensional cylindrical target structure. By adding the radial dimension and creating a hollow cylindrical geometry with inward-facing erosion surface, the plasma discharge is distributed along the curved surface in multiple directions, increasing the effective plasma volume and particle generation while maintaining spatial restriction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If conventional sputtering device is used, then film formation can be performed, but flat boardlike bodies cannot be properly film-formed

Engineering Contradiction:
Improvefilm formation capabilityVSAvoidapplicability to flat boardlike bodies
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The cylindrical target geometry with inward-facing erosion surface creates a radially symmetric sputtering field that is well-suited for coating flat boardlike substrates. The curved target surface provides uniform angular distribution of sputtered particles, enabling consistent film formation across flat substrates that cannot be achieved with conventional planar target configurations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention creates a sputtering system that can effectively handle multiple substrate types, particularly excelling with flat boardlike bodies while maintaining capability for other geometries. The cylindrical target design provides a versatile solution that addresses the specific need for flat substrate coating while preserving general film formation functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If film formation roller without thermal management is used, then film deposition occurs, but surface curvature and unevenness develop

Engineering Contradiction:
Improvefilm depositionVSAvoidsurface flatness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention incorporates a cooling system with flow passages integrated into the cylindrical target structure, using fluid circulation (water or gas) to actively manage thermal conditions during film deposition. This hydraulic cooling mechanism prevents heat accumulation that would cause thermal expansion and surface deformation, maintaining substrate flatness while enabling continuous high-productivity film formation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The invention actively controls the temperature parameter during the film formation process by implementing a cooling system. By maintaining constant temperature through active thermal management, the system prevents thermally-induced surface curvature and unevenness, ensuring manufacturing precision is maintained throughout the deposition process.

Inventive Principle:
Principle #35Parameter changes

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 tubular target design increases plasma density and deposition rates, while the advanced film formation roller ensures smooth film deposition and precise temperature control, preventing surface curvature and unevenness.

Implementation Method 1

discharge is performed, it is possible to generate a plasma circulating along the inner surface of the sputtering target

Methodology Applied
Scientific EffectPlasma discharge: Plasma

Implementation Method 2

the sputtering cathode... when discharge is performed, it is possible to generate a plasma circulating along the inner surface of the sputtering target on the side of the erosion surface

Methodology Applied
Scientific EffectSputtering: Sputtering

Implementation Method 3

a sputtering cathode comprising: a sputtering target (10) having a rectangular tubular shape in which the cross-sectional shape thereof is rectangular, and an erosion surface faces inward

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

a film formation roller with a cylindrical section made of copper, copper alloy, or aluminum alloy having a built-in flow passage

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3438322B1Sputtering device, and method for producing film-formed body
Publication Date: 2022.05.25 KEIHIN RAM TECH
  • EP3438322B1 patent drawingFigure 1
  • EP3438322B1 patent drawingFigure 2
  • EP3438322B1 patent drawingFigure 3

AI summary

This sputtering cathode has a sputtering target having a tubular shape in which the cross-sectional shape thereof has a pair of long side sections facing each other, and an erosion surface facing inward. Using the sputtering target, while moving a body to be film-formed, which has a film formation region having a narrower width than the long side sections of the sputtering target, parallel to one end face of the sputtering target and at a constant speed in a direction perpendicular to the long side sections above a space surrounded by the sputtering target, discharge is performed such that a plasma circulating along the inner surface of the sputtering target is generated, and the inner surface of the long side sections of the sputtering target is sputtered by ions in the plasma generated by a sputtering gas to perform film formation in the film formation region of the body to be film-formed.