Magnetron Sputter Chamber Layout for Piezoelectric Stress Control
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Solution Overview
Problem
Current vacuum equipment lacks adequate provisions for precise control of layer parameters and stress management in the deposition of piezoelectric layers for high-performance devices, such as microphones and sensors, which are critical for meeting the demands of miniaturization.
Innovation Solution
The development of a vacuum apparatus with specific design features, including a pedestal with an electrostatic chuck for stress control, a magnetron sputter source with a cooled back-plate, and a multi-chamber system (MCS) with advanced gas supply and temperature control mechanisms, to enhance process stability and reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional vacuum equipment is used for depositing piezoelectric layers, then basic deposition can be achieved, but process control precision and stress management are insufficient
Solution Approach 1:
The vacuum chamber is divided into multiple independent compartments (sputtering compartment, heating compartment, pumping compartment) separated by partition walls with controlled aperture openings. This segmentation allows independent control of process parameters in each compartment while maintaining overall system integrity, enabling precise layer parameter control without requiring complete system redesign.
Solution Approach 2:
A flow labyrinth structure is introduced as an intermediary element between compartments to control gas flow and plasma containment. The labyrinthine aperture openings provide precise control over process gas distribution and plasma confinement without requiring complex mechanical actuators, achieving improved manufacturing precision through passive flow control.
2Manufacturing precision
If the pedestal is fixed in position, then apparatus structure is simple, but film stress cannot be controlled and target erosion cannot be compensated
Solution Approach 1:
The pedestal is designed with vertical mobility, allowing it to move between different positions (first position for initial deposition, second position for stress control). This dynamic adjustment capability enables film stress control and target erosion compensation without requiring complex lateral positioning mechanisms, achieving precision control through simple vertical motion.
Solution Approach 2:
The system controls film stress by changing the vertical position parameter of the pedestal relative to the target. By adjusting the distance between substrate and target, the deposition conditions change, allowing stress control throughout the target lifetime without modifying other process parameters.
3Reliability
If plasma is allowed to spill into the pump compartment, then pumping efficiency is maintained, but process stability deteriorates and plasma power is lost
Solution Approach 1:
The flow labyrinth structure extracts and redirects plasma flow before it can spill into the pump compartment. The labyrinthine aperture openings create a controlled barrier that separates plasma-containing regions from pump regions, preventing plasma contamination of the pumping system while maintaining efficient gas removal through the same structural element.
4Productivity
If the aperture opening area between compartments is large, then gas flow is efficient, but plasma containment deteriorates and process stability worsens
Solution Approach 1:
The aperture openings are designed with labyrinthine (curved/complex) geometry rather than simple straight channels. This curved path design maintains adequate flow conductance for efficient gas removal while the increased path length and complexity provide effective plasma containment, resolving the contradiction between flow efficiency and plasma containment.
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 solution provides improved process control, minimizing pressure fluctuations and stress within the piezoelectric layers, resulting in higher precision and performance of the deposited coatings, which is essential for advanced piezoelectric devices.
Implementation Method 1
a pedestal comprising an electrostatic chuck formed as a substrate support
Implementation Method 2
by sputtering... a magnetron sputter source comprising the, e.g. metallic or alloy target
Data Source
AI summary
A vacuum apparatus to deposit a compound layer on at least one plate shaped substrate by sputtering. The apparatus including a vacuum chamber with side walls around a central axis. The chamber includes at least one inlet for a process gas, at least one inlet for an inert gas, a substrate handling opening, a pedestal including an electrostatic chuck formed as a substrate support in a central lower area of a sputter compartment, a magnetron sputter source including the target at the frontside and a magnet-system at the backside of the source, an anode looping around the target and at least an upper part of the pedestal and a pump compartment connected to a bottom of the sputter compartment by a flow labyrinth. A vacuum pump system is connected to the pump compartment.