SiC Sputtering Target Texture for Optical Film Stability
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Solution Overview
Problem
Conventional SiC targets used in sputtering for optical recording media are prone to cracking, abnormal discharge, and impurity-related absorption issues, leading to low productivity and signal strength, and are costly due to high sintering temperatures and impurity elements.
Innovation Solution
A sputtering target with a texture of silicon carbide (SiC) crystal grains and a continuous silicon phase in a network shape, sintered with a reduced amount of metal sintering aids, is used to deposit a SiOC film with controlled impurity levels, enhancing strength, reducing abnormal discharge, and improving optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional SiC target is used for sputtering, then high deposition rate is achieved, but target easily cracks and causes abnormal discharge
Solution Approach 1:
The patent changes the microstructural parameters of the SiC target by controlling grain size (1-10 μm) and porosity (3-15%), transforming the target from a coarse-grained high-porosity structure to a fine-grained low-porosity structure. This parameter optimization resolves the contradiction by maintaining high deposition rate while preventing cracking and abnormal discharge through improved structural integrity.
Solution Approach 2:
The patent creates a composite microstructure within the SiC target comprising silicon carbide grains embedded in a silicon oxide matrix. This composite structure combines the high deposition rate capability of SiC with the mechanical strength and stability of SiO2, preventing target cracking and abnormal discharge while maintaining productivity.
2Strength
If sintering aid is added to improve target density, then target strength increases, but impurity elements cause abnormal discharge
Solution Approach 1:
The patent extracts and eliminates sintering aid impurities from the target composition, achieving high-density SiC structure through alternative sintering methods. By removing the harmful sintering aids that cause abnormal discharge, the patent resolves the contradiction between obtaining strong targets and avoiding impurity-related discharge issues.
Solution Approach 2:
The patent uses minimal or no sintering aids, treating them as temporary process auxiliaries rather than permanent target components. This approach allows achieving target density during manufacturing without introducing persistent impurity sources that would cause abnormal discharge during operation.
3Volume of stationary object
If high sintering temperature is used to achieve high density, then target density increases, but manufacturing cost increases
Solution Approach 1:
The patent changes the sintering parameters from extremely high temperature (2000°C) to moderate temperature (1800-1950°C) while optimizing pressure conditions and atmosphere control. This parameter optimization achieves high target density at lower cost by reducing energy consumption and equipment requirements while maintaining structural integrity.
Solution Approach 2:
The patent applies partial sintering action, achieving sufficient density (95-98% theoretical density) without complete sintering at maximum temperature. This partial action approach reduces manufacturing cost and energy consumption while obtaining targets with adequate density and performance for sputtering applications.
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 approach results in a high-density, low-absorption SiOC film with improved thermal conductivity and reduced variation in medium characteristics, enabling high productivity and cost-effective optical recording media with enhanced signal strength and reflectance contrast.
Implementation Method 1
a sputtering target containing Si and C as its major components, and including a texture having silicon carbide (SiC) crystal grains and a silicon (Si) phase
Data Source
AI summary
A sputtering target contains Si and C as its major components and includes a texture in which a Si phase continuously exists in a net shape in gaps among SiC crystal grains. An average diameter of the Si phase is controlled to 1000 nm or less. The sputtering target is sputtered in an oxygen-containing gas, thereby depositing an optical thin film containing Si and O as its major components, and a third element other than the major components, a total amount of the third element being within a range from 10 to 2000 ppm.