Rotatable Sputtering Target Uniformity Control
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Solution Overview
Problem
Existing sputtering methods face challenges in achieving high uniformity of sputtered material layers over extensive substrates due to irregular spatial distribution, particularly in applications requiring stringent uniformity like TFTs, where non-uniform layers can lead to manufacturing reproducibility issues and signal delays.
Innovation Solution
The method involves varying the relative position between rotatable targets and substrates during sputtering by maintaining positions for predetermined time intervals, using a reciprocating motion to achieve a high degree of uniformity, and applying non-constant voltage synchronized with the target-substrate movement to enhance layer homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional sputtering with stationary targets is used, then the process is simple, but layer uniformity over extensive substrates deteriorates
Solution Approach 1:
The patent applies the dynamics principle by making the target rotatable instead of stationary. The target rotates during sputtering to dynamically change the spatial distribution of sputtered material across the substrate, thereby achieving improved layer uniformity over extensive substrate areas while managing process complexity
Solution Approach 2:
The patent implements periodic action through the rotational movement of the target. The target undergoes periodic rotation cycles, creating time-dependent variations in material deposition patterns that result in more uniform layer formation across the entire substrate surface
2Manufacturing precision
If multiple targets are provided to improve layer uniformity, then layer uniformity improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing a single target into multiple rotational segments or zones. Each segment can be independently controlled or positioned, allowing different areas of the target to deposit material at different times, thereby achieving uniform coverage across the substrate using one segmented target rather than multiple complete targets
Solution Approach 2:
The patent uses dynamic rotation of a single target to replace the static configuration of multiple targets. By rotating the target, different portions of its surface are brought into position to deposit material on different areas of the substrate, achieving the uniformity effect of multiple targets with a single dynamic component
3Manufacturing precision
If the target is rotated at constant angular velocity, then the process is simple to control, but layer uniformity remains insufficient for high-precision applications
Solution Approach 1:
The patent applies parameter changes by varying the angular velocity of the rotating target during the sputtering process. Instead of maintaining constant rotation speed, the system adjusts rotational speed as a controllable parameter to optimize deposition patterns and achieve the required layer uniformity for high-precision applications
Solution Approach 2:
The patent implements periodic variations in the rotation cycle, including acceleration, deceleration, and pausing at specific angular positions. This periodic action allows precise control over when different target segments deposit material, enabling fine-tuning of layer uniformity while maintaining operational control through programmed sequences
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
This approach results in highly uniform layers with improved homogeneity in terms of thickness, crystal structure, and specific resistance, addressing the limitations of traditional sputtering techniques by ensuring consistent coating across large areas.
Implementation Method 1
During sputtering, atoms are ejected from the target material by bombardment thereof with energetic particles (e.g., energized ions of an inert or reactive gas). Thereby, the ejected atoms may deposit on the substrate, so that a layer of sputtered material can be formed.
Data Source
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AI summary
The present disclosure describes a method of coating a substrate (110), the method including forming a layer (806) of sputtered material on the substrate (110). Forming the layer of sputtered material may include: sputtering material from at least one rotatable target (120') over the substrate (110); varying the relative position between the at least one target (120') and the substrate (110). In addition, the present disclosure describes varying the distance between a target (120; 120'; 120'') and a substrate during the sputter process. The present disclosure further describes a system for coating a substrate.