IGZO Sintered Target Void Control for Sputtering Particle Reduction
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Solution Overview
Problem
Large-sized sputtering targets used for producing oxide semiconductor thin films often suffer from particle generation during high-power sputtering, which affects the quality and durability of the films, particularly for materials like indium gallium zinc oxide (IGZO) and indium gallium oxide (IGO).
Innovation Solution
A sintered body with a low void ratio of 0.03 vol% or less, specifically designed with an atomic ratio of Ga/(In+Ga) between 0.01 and 0.13 and comprising a bixbyite structure, is produced using a controlled sintering process with varying heating rates and retention times in an oxygen-containing atmosphere, resulting in a target with reduced particle formation during sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sputtering is conducted at high power (3 W/cm2 or more) using a large-sized target (area exceeding 25000 mm2), then film formation efficiency is improved, but particle generation occurs
Solution Approach 1:
The invention changes the physical parameters of the sintered body by controlling the void ratio to be 0.04 or less and the average void diameter to be 30 μm or less. This parameter optimization allows the target to withstand high sputtering power without particle generation, thus improving film formation efficiency while preventing harmful particle generation.
Solution Approach 2:
The invention applies local quality control by specifically managing the distribution and size of voids within the sintered body. By ensuring that individual voids do not exceed 30 μm in diameter and the overall void ratio is 0.04 or less, the target achieves uniform material ejection during sputtering, preventing particle generation while maintaining high productivity.
2Manufacturing precision
If sintering temperature is increased to 1400° C. or higher to produce IGZO sintered body, then material density is improved, but large voids may form
Solution Approach 1:
The invention applies preliminary action by implementing a multi-stage sintering process with controlled heating rates. The heating rate is specifically controlled to be 0.1 to 1.0° C./min in the range of 900 to 1400° C., which allows gradual densification and prevents sudden void formation. This preliminary controlled heating ensures material density improvement while preventing large void formation.
Solution Approach 2:
The invention uses dynamics by implementing a dynamic heating rate control strategy. The heating rate is adjusted at different temperature stages: 0.1 to 1.0° C./min from room temperature to 900° C., then 0.1 to 1.0° C./min from 900 to 1400° C., and finally a cooling rate of 0.1 to 1.0° C./min. This dynamic adjustment optimizes densification while preventing void formation.
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 solution enables the production of high-quality, long-running oxide semiconductor thin films without particle generation, even at high sputtering powers, suitable for large-area displays and solar batteries, with improved yield and efficiency.
Implementation Method 1
a sintering step in which the shaped body is sintered to obtain a sintered body
Implementation Method 2
gallium is solid dissolved in an indium site
Implementation Method 3
glow discharge is allowed to occur between a substrate as the anode and a target as the cathode in an argon gas pressure of about 10 Pa or less, thereby to generate argon plasma
Implementation Method 4
Argon positive ions in this plasma collide with the target as the cathode to cause the particles of the target components to fly off, and these particles are then deposited on the substrate to form a film
Implementation Method 5
a sintering step in which the shaped body is sintered to obtain a sintered body; in an oxygen-containing atmosphere
Data Source
AI summary
A sintered body which includes at least indium oxide and gallium oxide and comprises voids each having a volume of 14000 μm3 or more in an amount of 0.03 vol % or less.