Potassium sodium niobate sputtering target and production method thereof

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Solution Overview

Problem

The challenge is to develop a high-density potassium sodium niobate sputtering target with superior piezoelectric properties to replace lead-based PZT, which is environmentally hazardous, and to enable industrial-scale film deposition using the sputtering method, as existing targets suffer from low density and sintering difficulties.

Innovation Solution

A method involving the mixing of Nb2O5, K2CO3, and Na2CO3 powders, followed by pulverization and hot press sintering in an inert gas or vacuum atmosphere at specific temperatures and pressures, combined with optional heat treatment or HIP processes, to achieve a sputtering target with a relative density of 95% or higher, average crystal grain size of 1-20 μm, and controlled volume resistivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional sintering methods are used for potassium sodium niobate, then the sintering process can be simplified, but the resulting target has low density and poor mechanical properties

Engineering Contradiction:
Improvesintering process simplicityVSAvoidtarget density
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies hot press sintering with specific parameter ranges: temperature of 900-1150°C, pressure of 150-400 kgf/cm², and time of 2-6 hours. These controlled parameter changes enable achievement of 95% or higher relative density while maintaining process feasibility, resolving the contradiction between manufacturing simplicity and target density.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If hot press sintering is applied to achieve high density, then target density improves, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvetarget densityVSAvoidsintering process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines heating and pressing operations into a single hot press sintering step, rather than performing density enhancement and shaping as separate operations. This merging achieves high density (95% or higher) while consolidating process complexity into one integrated step, making the overall process more manageable despite the advanced equipment required.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If the sputtering target has high density, then film deposition quality improves, but particle generation and crack formation increase during sputtering

Engineering Contradiction:
Improvefilm deposition qualityVSAvoidtarget stability during sputtering
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent optimizes crystal grain size to a specific range of 1-20 μm through controlled hot press sintering parameters. This parameter optimization achieves the dual benefit of high film deposition quality and reduced particle generation/crack formation during sputtering, resolving the contradiction between density-related quality and target stability.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If lead-based PZT is used, then piezoelectric properties are superior, but environmental burden increases due to lead content

Engineering Contradiction:
Improvepiezoelectric propertiesVSAvoidenvironmental burden
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material composition from lead-based PZT to potassium sodium niobate with specific compositional ratios (0.3 ≤ x ≤ 0.7 in (1-x)KNaNbO3-xNbO3). This compositional parameter change achieves piezoelectric properties comparable to PZT while eliminating lead content, resolving the contradiction between performance and environmental burden.

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 resulting potassium sodium niobate sputtering target exhibits high strength, stability, and uniform film deposition, suppressing particle generation and crack formation, enabling effective industrial use and performance comparable to PZT.

Implementation Method 1

performing hot press sintering to the obtained pulverized powder in an inert gas or vacuum atmosphere under conditions of a temperature of 900° C. or higher and less than 1150° C., and a load of 150 to 400 kgf/cm2

Methodology Applied
Scientific EffectHot press sintering: Sintering

Implementation Method 2

industrially deposit potassium sodium niobate films via the sputtering method

Methodology Applied
Scientific EffectSputtering: Sputtering

Data Source

PatentUS11851747B2Potassium sodium niobate sputtering target and production method thereof
Publication Date: 2023.12.26 JX NIPPON MINING & METALS CORP

AI summary

A potassium sodium niobate sputtering target having a relative density of 95% or higher. A method of producing a potassium sodium niobate sputtering target, including the steps of mixing a Nb2O5 powder, a K2Co3 powder, and a Na2Co3 powder, pulverizing the mixed powder to achieve a grain size d50 of 100 μm or less, and performing hot press sintering to the obtained pulverized powder in an inert gas or vacuum atmosphere under conditions of a temperature of 900° C. or higher and less than 1150° C., and a load of 150 to 400 kgf/cm2. The present invention aims to provide a high density potassium sodium niobate sputtering target capable of industrially depositing potassium sodium niobate films via the sputtering method.