Dual-Target Sputtering Layout for Low-Temperature GaN Deposition
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Solution Overview
Problem
Existing sputtering methods struggle to deposit gallium nitride films at low temperatures, limiting the ability to form micro LED devices on glass substrates and requiring separate chambers for films with different compositions.
Innovation Solution
A sputtering apparatus with dual rotary targets and a partition wall, allowing for the simultaneous deposition of multiple materials on a substrate by alternating plasma generation and substrate movement, enabling the formation of stacked structures like AlGaN/GaN layers in a single chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If gallium nitride film is deposited using conventional sputtering methods, then deposition can be achieved, but high temperature (800-1000°C) is required which limits substrate material choices
Solution Approach 1:
The patent combines multiple sputtering chambers into a single integrated apparatus with shared substrate handling. The first chamber deposits GaN layer and the second chamber deposits AlGaN layer, both on the same substrate without external intervention. This merging allows low-temperature deposition on glass substrates while maintaining process continuity.
Solution Approach 2:
The deposition process is segmented into two separate chambers, each optimized for specific layer deposition. The first chamber is dedicated to GaN layer formation and the second to AlGaN layer formation. This segmentation enables independent optimization of deposition conditions for each layer while maintaining low overall process temperature.
2Manufacturing precision
If multiple chambers are used for depositing films with different compositions, then film quality can be maintained, but process complexity and time increase
Solution Approach 1:
Both chambers are designed with universal sputtering capabilities using magnetron sputtering technology. Each chamber can deposit different materials (GaN, AlGaN) with the same fundamental process, allowing simplified control while maintaining film quality. The substrate hold portion and plasma generation mechanisms are standardized across chambers.
Solution Approach 2:
The substrate is prepared in advance by loading it onto the substrate hold portion before entering the first chamber. The sequential deposition process is pre-programmed, with the substrate automatically transferred from the first chamber to the second chamber without manual intervention, reducing operational complexity.
3Manufacturing precision
If multiple chambers are used for sequential deposition, then layer interfaces can be controlled, but contamination risk increases at transfer points
Solution Approach 1:
The two chambers are merged into a single integrated apparatus with a shared vacuum environment and continuous substrate transport path. The substrate is transferred internally from the first chamber to the second chamber without exposure to external atmosphere, eliminating contamination risks at transfer points while maintaining clean layer interfaces.
4Ease of manufacture
If conventional single-target sputtering is used, then process simplicity is maintained, but deposition of stacked structures requires separate processes
Solution Approach 1:
The substrate undergoes continuous deposition without interruption or removal from the apparatus. After depositing the GaN layer in the first chamber, the substrate is automatically transferred to the second chamber for AlGaN layer deposition, maintaining continuous useful action. This eliminates idle time and manual handling steps, significantly improving productivity while keeping the process straightforward.
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 low-temperature deposition of gallium nitride films on glass substrates, reducing contamination and ensuring high reliability and mobility of semiconductor devices by maintaining clean interfaces between layers.
Implementation Method 1
a sputtering method using a rotary target... depositing the first material of the first target to the substrate by moving the first target and the substrate hold portion relatively while generating plasma for the first target... depositing the second material of the second target to the substrate by moving the second target and the substrate hold portion relatively while generating plasma for the second target
Implementation Method 2
generating plasma for the first target in a first step... generating plasma for the second target in a second step
Data Source
AI summary
A sputtering apparatus includes: a substrate hold portion configured to hold a substrate; a first target facing the substrate hold portion; a second target facing the substrate hold portion and arranged side by side with the first target; and a partition wall between the first target and the second target, wherein each of a first normal line in an arbitrary position of the first target and a second normal line in an arbitrary position of the second target is connected to an arbitrary point on the substrate.