Cylindrical Sputtering Target Shrinkage Control

Solution Overview

Problem

Cylindrical ceramic sputtering targets face challenges in achieving high density without sintering shrinkage-induced cracks and deformation, and existing methods for bonding to substrates are prone to breakage, limiting reuse and recycling.

Innovation Solution

A hollow cylindrical ceramic sintered body with a relative density of 95% or higher is produced by sintering on a plate-like ceramic molding with similar sintering shrinkage, and bonded to a cylindrical substrate using a low melting solder, allowing for high-quality targets without cracks or breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If density of cylindrical ceramic target is increased using sintering method, then target quality is improved, but sintering shrinkage increases causing cracks and deformation

Engineering Contradiction:

Improvetarget qualityVSAvoidstructural integrity

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The patent applies preliminary action by pre-forming green bodies with controlled density and uniform particle distribution before sintering. This preliminary preparation ensures that during sintering, the shrinkage occurs uniformly without causing cracks or deformation, thus achieving high density targets with maintained structural integrity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by optimizing sintering temperature, holding time, and atmospheric conditions to achieve the desired density while controlling shrinkage. By carefully adjusting these parameters, the sintering process produces high-quality targets without the harmful effects of excessive shrinkage-induced cracking.

Inventive Principle:

Principle #35Parameter changes

2Strength

If conventional bonding methods are used to attach target to cylindrical substrate, then target is fixed, but cracks and breakage occur during bonding

Engineering Contradiction:

Improvebonding strengthVSAvoidbonding reliability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing bonding temperature, pressure, and time parameters to achieve strong bonding without causing cracks or breakage. The bonding process is carefully controlled within specific parameter ranges that ensure both bonding strength and structural integrity of the ceramic target.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs beforehand cushioning by using intermediate bonding layers or transition materials that absorb thermal stress and mechanical stress during the bonding process. This cushioning effect prevents cracks and breakage while ensuring reliable bonding between the ceramic target and the cylindrical substrate.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If high density sintered body is produced, then sputtering rate increases, but sintering shrinkage causes deformation

Engineering Contradiction:

Improvesputtering rateVSAvoidtarget shape

Core Design Contradiction:

ProductivityVSShape

Solution Approach 1:

The patent applies preliminary action by pre-forming green bodies with controlled density and uniform particle distribution before sintering. This preliminary preparation ensures that during sintering, the shrinkage occurs uniformly without causing cracks or deformation, thus achieving high density targets with maintained structural integrity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by optimizing sintering temperature, holding time, and atmospheric conditions to achieve the desired density while controlling shrinkage. By carefully adjusting these parameters, the sintering process produces high-quality targets without the harmful effects of excessive shrinkage-induced cracking.

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 process achieves a high-density ceramic sputtering target with reduced sintering shrinkage and bonding-related issues, enabling efficient production and reuse of targets, even with expensive materials like Cu, while maintaining high film quality under high electric power density.

Implementation Method 1

a ceramic green body is sintered to obtain a ceramic sintered body

Methodology Applied

Scientific EffectSintering: Sintering

Implementation Method 2

bonded to a cylindrical substrate using a low melting solder

Methodology Applied

Scientific EffectSoldering: Soldering

Data Source

PatentUS8206561B2Cylindrical sputtering target, ceramic sintered body, and process for producing sintered body

Publication Date: 2012.06.26 TOSOH CORP

AI summary

A hollow cylindrical ceramic sintered body having high density, a process for producing the sintered boy, and a cylindrical ceramic sputtering target having high quality without cracks or breakage, are disclosed. The hollow cylindrical ceramic sintered body is obtained by placing a cylindrical ceramic molding to be sintered on a plate-like ceramic molding having a coefficient of sintering shrinkage similar to that of the cylindrical ceramic molding, and then sintering the resulting assembly, thereby obtaining a hollow cylindrical ceramic sintered body having a relative density of 95% or higher. The cylindrical ceramic sputtering target is prepared using the hollow cylindrical ceramic sintered body.