Niobium Sputtering Target Texture Control for Film Thickness Uniformity
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Solution Overview
Problem
Niobium sputtering targets face challenges in maintaining film thickness uniformity due to variations in crystal orientation across the target, leading to inconsistent sputtering characteristics and reduced target life.
Innovation Solution
A niobium sputtering target with controlled {111} and {100} area ratios and average crystal grain sizes across its upper, central, and lower portions, achieved through specific rolling and heat treatment processes, to minimize the rate of change in these parameters, ensuring uniform film deposition throughout the target life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional niobium sputtering targets are used, then sputtering process can be performed, but film thickness uniformity deteriorates due to variations in crystal orientation across the target
Solution Approach 1:
The patent applies parameter changes by controlling the crystal orientation parameters ({111} area ratio and average crystal grain size) within specific ranges. By adjusting these parameters through controlled rolling and heat treatment processes, the invention achieves uniform film thickness while maintaining stable crystal orientation distribution across the target surface.
Solution Approach 2:
The patent applies local quality by ensuring that the crystal orientation parameters are uniformly distributed across different regions (upper, central, and lower portions) of the target. The controlled rolling and heat treatment processes create consistent local crystal structures throughout the target, preventing variations that would otherwise lead to non-uniform film deposition.
2Reliability
If conventional niobium sputtering targets are used, then sputtering can be performed, but reactive sputtering stability deteriorates
Solution Approach 1:
The patent improves reactive sputtering stability by changing the crystal orientation parameters to specific ranges. By controlling the {111} area ratio to 5-65% and average crystal grain size to 10-200 μm, the target achieves stable reactive sputtering characteristics throughout its operational life.
Solution Approach 2:
The patent applies preliminary action by pre-controlling the crystal orientation and grain size distribution before the sputtering process begins. The controlled rolling and heat treatment processes establish the desired crystal structure in advance, ensuring stable reactive sputtering performance without requiring adjustments during operation.
3Duration of action of stationary object
If conventional niobium sputtering targets are used, then production can proceed, but target life is reduced due to inconsistent sputtering characteristics
Solution Approach 1:
The patent extends target life by optimizing the crystal orientation parameters. By controlling the {111} area ratio and average crystal grain size within specific ranges, the target maintains consistent sputtering characteristics throughout its entire service life, preventing premature degradation and extending operational duration.
Solution Approach 2:
The patent ensures continuous useful action by maintaining stable film deposition characteristics throughout the target's operational life. The controlled crystal structure prevents variations in sputtering rate and film quality, allowing the target to perform its function consistently from beginning to end without interruption or degradation.
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 controlled crystal orientation and grain size distribution result in improved film thickness uniformity and stability, enhancing the efficiency and reliability of the sputtering process, particularly for advanced applications like quantum computers.
Implementation Method 1
Sputtering methods for forming coatings of metals, ceramics, and the like are used in many fields
Implementation Method 2
measuring a crystal orientation distribution of each of the upper portion, the central portion, and the lower portion using a EBSD method
Data Source
AI summary
Provided is a niobium sputtering target having improved film thickness uniformity throughout the target life.In the niobium sputtering target, a rate of change in a {111} area ratio of each of an upper, central, and lower portions of the sputtering target, as represented by the following equation (2), is 2.5 or less, and the {111} area ratio of each of the upper, central and lower portions is determined by dividing a cross section of a plate-shaped sputtering target perpendicular to a sputtering surface into three equal portions: the upper portion, the central portion and the lower portion from a sputtering surface side in a normal direction of the sputtering surface at an intermediate position between a center and an outer circumference of the sputtering surface of the plate-shaped sputtering target, and measuring a crystal orientation distribution of each of measured regions of the upper portion, the central portion, and the lower portion using an EBSD method:the {111} area ratio=total area of crystal grains having a {111} plane oriented in the normal direction in the measured regions/total area of the measured regions Equation (1);the rate of change=[maximum value−minimum value]/minimum value Equation (2).