Piezoelectric Sensor Cavity Structure With Low-Temperature PECVD
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Solution Overview
Problem
Existing piezoelectric sensor manufacturing processes require high temperatures and complex procedures, such as thermal oxidation layer growth, which complicate the production and reduce product yield.
Innovation Solution
A novel piezoelectric sensor structure and manufacturing method that involves forming a cavity on an array substrate using plasma enhanced chemical vapor deposition and wet etching, allowing direct integration of piezoelectric sensing units without the need for transfer processes, thereby simplifying the manufacturing process and improving yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-temperature thermal oxidation is used to form the cavity structure, then the cavity can be created, but the manufacturing process becomes complex and requires high temperature processing
Solution Approach 1:
The patent changes the processing parameters from high-temperature thermal oxidation to plasma enhanced chemical vapor deposition (PECVD), operating at lower temperatures (typically 200-400°C). This parameter change maintains the ability to form precise cavity structures while eliminating the need for high-temperature processing equipment and complex thermal management, thereby reducing manufacturing process complexity
Solution Approach 2:
The patent replaces the thermal field-based thermal oxidation process with a plasma field-based PECVD process. This substitution uses plasma chemistry instead of thermal diffusion, enabling cavity formation at lower temperatures with better process control and reduced equipment complexity, while maintaining manufacturing precision
2Ease of manufacture
If a pre-manufactured sensing unit is transferred to the substrate, then the sensor can be assembled, but the manufacturing process becomes complex and product yield decreases
Solution Approach 1:
The patent merges the cavity structure fabrication and the sensing unit formation into a single integrated manufacturing process. Both structures are formed in-situ on the substrate using the same PECVD process sequence, eliminating the need for separate pre-manufacturing and transfer operations. This integration simplifies the manufacturing process and eliminates yield losses associated with transferring pre-manufactured units
Solution Approach 2:
The patent performs preliminary formation of both the cavity structure and the sensing unit components directly on the substrate before final assembly. The PECVD process deposits layers that form both structures simultaneously in their final positions, eliminating subsequent transfer and assembly steps, thereby simplifying manufacturing and improving product yield
3Reliability
If the cavity size and electrode placement are not precisely controlled, then the manufacturing is simpler, but the signal reception and sensor performance deteriorate
Solution Approach 1:
The PECVD process incorporates real-time monitoring and feedback control of deposition rate, film thickness, and plasma parameters. This feedback mechanism enables precise control of cavity dimensions and electrode placement by adjusting process parameters based on measured deviations, ensuring high manufacturing precision while maintaining reliable signal reception
Solution Approach 2:
The patent replaces mechanical or thermal processes with plasma-based PECVD, which offers superior process control through electrical parameter management. Plasma processes provide better deposition uniformity, sharper feature definition, and more precise thickness control, enabling accurate cavity size and electrode placement control for optimal signal reception
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 method reduces process complexity and difficulty, enabling higher resolution cavity structures and improved product performance by directly forming the piezoelectric sensing unit on the array substrate, enhancing signal reception and reducing leakage currents.
Implementation Method 1
the capping layer is formed using plasma enhanced chemical vapor deposition to create a cavity
Implementation Method 2
A piezoelectric sensor is a sensor manufactured by utilizing a piezoelectric effect generated after a piezoelectric material is stressed. When deformation (including bending and stretching deformation) occurs in the piezoelectric material in the piezoelectric sensor under an external force, charges will be generated on a surface of the piezoelectric sensor due to polarization of internal charges
Data Source
AI summary
A piezoelectric sensor and a manufacturing method therefor, and a detection apparatus, which relate to the technical field of sensing. The piezoelectric sensor includes: an array substrate; a first capping layer located on the array substrate and including a first portion and a second portion, wherein the first portion covers the array substrate, a cavity is provided between the second portion and the array substrate, and the second portion is provided with a first opening; a first electrode located above the first capping layer and above the cavity, a piezoelectric thin film located on the first electrode; and a second electrode located on the piezoelectric thin film.