Rotary Sputtering Targets for Thin-Film Thickness and Composition Control
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Solution Overview
Problem
Existing sputtering methods struggle to efficiently fabricate highly crystalline thin films of materials like gallium nitride and indium nitride, which are crucial for semiconductor devices, due to limitations in controlling film thickness and composition during deposition.
Innovation Solution
A sputtering apparatus and method utilizing rotary targets with parallel rotation axes and a moving substrate, combined with controlled plasma generation and substrate movement, allows for precise deposition of films with varying thicknesses and compositions by adjusting target radii, distances, and plasma localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sputtering methods are used, then fabrication of thin films is achieved, but control over film thickness and composition is insufficient
Solution Approach 1:
The patent employs rotary targets that rotate during sputtering, transforming static target materials into dynamically exposed surfaces. This rotation enables continuous variation of film composition and thickness control without requiring multiple discrete targets, resolving the contradiction between precision control and system complexity
Solution Approach 2:
The invention introduces a temporal dimension to the sputtering process by rotating targets, allowing composition control through rotation speed and position. This adds a new degree of freedom (rotation angle/time) to the traditionally static sputtering parameters, enabling precise film property control without increasing spatial complexity
2Adaptability or versatility
If multiple targets are used to control film composition, then material variety increases, but device complexity and space requirements increase
Solution Approach 1:
The patent divides a single rotary target into multiple segmented regions, each containing different materials. As the target rotates, different segments are exposed to the plasma, enabling deposition of multiple materials from a single target structure, thus achieving material variety without requiring multiple separate targets in the chamber
Solution Approach 2:
A single rotary target structure serves multiple functions: it can deposit different materials at different angular positions, control film thickness through rotation speed, and adjust composition ratios by controlling the exposure time of different segments. This multi-functionality eliminates the need for multiple separate targets, reducing chamber space requirements
3Reliability
If sputtering is performed on stationary targets, then process simplicity is maintained, but film uniformity and crystallinity are insufficient
Solution Approach 1:
The rotary targets rotate during sputtering, creating dynamic exposure conditions that promote uniform film deposition and enhance crystallinity. The continuous rotation prevents localized overheating and ensures even material distribution, improving film quality without significantly reducing deposition efficiency
Solution Approach 2:
The periodic rotation of the targets creates cyclic exposure patterns where different target segments are alternately exposed to plasma. This periodic action promotes uniform film growth and enhances crystalline structure formation, while the controlled rotation speed maintains reasonable deposition rates
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
Enables the fabrication of highly crystalline thin films with precise thickness and composition control, suitable for semiconductor devices, including light-emitting diodes and transistors, on large substrates like glass and plastic, at reduced costs.
Implementation Method 1
performing sputtering on a plurality of rotary targets arranged so that rotation axes thereof are parallel to one another
Implementation Method 2
controlled plasma generation and substrate movement
Data Source
AI summary
The deposition method includes performing sputtering on a plurality of rotary targets arranged so that rotation axes thereof are parallel to one another while moving a substrate in a direction perpendicular to the rotation axes. The plurality of rotary targets is each positioned on one side of the substrate. The plurality of rotary targets includes a first rotary target and a second rotary target having a smaller radius than the first rotary target.