Oxide Sintered Material for Sputtering Targets
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Solution Overview
Problem
Existing oxide sintered materials used in sputtering processes for semiconductor devices face issues with abnormal discharge and high pore content, leading to reduced productivity and semiconductor performance, particularly due to limitations in sintering temperature and density.
Innovation Solution
An oxide sintered material comprising In2O3, Zn4In2O7, and ZnWO4 crystal phases with controlled roundness and composition is developed, which reduces abnormal discharge and pore content, and can be produced at lower sintering temperatures, enhancing semiconductor device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional oxide sintered materials are used as sputtering targets, then semiconductor devices can be manufactured, but abnormal discharge occurs and pore content increases, reducing productivity and device performance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the sintering temperature (900-1100°C) and duration (1-6 hours) to optimize the crystal phase composition. This results in an oxide sintered material with specific phase ratios (In-Ga-Zn-O: 60-80 at%, In-Zn-O: 10-30 at%, In-O: 5-20 at%) that eliminates abnormal discharge during sputtering while maintaining high density and low pore content, thereby improving both reliability and reducing harmful factors simultaneously
Solution Approach 2:
The patent creates a composite oxide sintered material comprising multiple crystal phases (In-Ga-Zn-O, In-Zn-O, and In-O) with controlled compositions and ratios. This multi-phase composite structure achieves synergistic effects where the dominant In-Ga-Zn-O phase provides high carrier mobility and semiconductor performance, while the controlled presence of In-Zn-O and In-O phases contributes to density and pore reduction, eliminating abnormal discharge during sputtering
2Quantity of substance
If high sintering temperature is used to increase density, then pore content decreases, but manufacturing cost and energy consumption increase
Solution Approach 1:
The patent optimizes the sintering parameters by conducting sintering at 900-1100°C for 1-6 hours, which achieves high density (reduced pore content) without requiring excessively high temperatures. This parameter optimization reduces energy consumption compared to conventional high-temperature sintering while still achieving the desired density and phase composition for high-performance semiconductor devices
Solution Approach 2:
The patent performs preliminary mixing and homogenization of the oxide powder composition before sintering, ensuring uniform distribution of In, Ga, Zn, and O elements. This preliminary action allows for more efficient sintering at lower temperatures (900-1100°C) because the uniform composition facilitates complete reaction and densification without requiring excessive thermal energy, thereby reducing energy consumption while achieving high density
3Productivity
If sputtering is performed with conventional oxide targets, then oxide semiconductor films can be formed, but abnormal discharge reduces productivity
Solution Approach 1:
The patent changes the compositional parameters of the oxide sintered material by controlling the atomic ratios and phase compositions (In-Ga-Zn-O: 60-80 at%, In-Zn-O: 10-30 at%, In-O: 5-20 at%). This parameter optimization eliminates abnormal discharge during sputtering, allowing for stable and continuous film formation processes that improve productivity and manufacturing efficiency
Solution Approach 2:
The patent achieves local quality optimization by creating specific crystal phases with controlled distributions within the oxide sintered material. The dominant In-Ga-Zn-O phase (60-80 at%) provides excellent sputtering characteristics and film quality, while the controlled presence of In-Zn-O (10-30 at%) and In-O (5-20 at%) phases locally modifies the structure to eliminate abnormal discharge, enabling stable high-speed manufacturing
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 material effectively reduces abnormal discharge and pore content, enabling the production of semiconductor devices with improved field-effect mobility and reliability, even when annealed at high temperatures.
Implementation Method 1
Japanese Patent Laying-Open No. 2008-199005 (PTL 1) discloses that an oxide semiconductor film mainly composed of IGZO is formed by a sputtering method using an oxide sintered material as a target.
Implementation Method 2
forming the oxide sintered material by sintering a molded body containing indium, tungsten and zinc
Data Source
AI summary
Provided are: an oxide sintered material including an In2O3 crystal phase, a Zn4In2O7 crystal phase and a ZnWO4 crystal phase, wherein the roundness of crystal particles composed of the ZnWO4 crystal phase is 0.01 or more and less than 0.7; a method for producing the oxide sintered material; and a method for manufacturing a semiconductor device including an oxide semiconductor film that is formed by using the oxide sintered material as a sputter target.