MEMS Cap Cavity Structure for Low-Temperature Sacrificial Etching
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Solution Overview
Problem
Existing methods for manufacturing MEMS devices with hollow or cavity sealing structures face challenges such as substrate cracking due to temperature changes and residual etching solution within the cavity, which affect productivity and structural strength.
Innovation Solution
A method involving a substrate with a sacrificial layer, a cap layer formed using TEOS-CVD silicon dioxide with carbon, and peripheral holes to facilitate low-temperature wet etching, reducing etching solution residue and enhancing structural strength by allowing efficient drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rapid heating and cooling processes are used during thermal processes, then manufacturing productivity is improved, but substrate cracking occurs
Solution Approach 1:
The patent changes the temperature parameter by performing the etching process at low temperature (room temperature or below) instead of high temperature, thereby avoiding substrate cracking while maintaining manufacturing productivity. The low-temperature etching allows rapid processing without thermal stress that causes cracking.
2Strength
If wet etching process is performed under low temperatures, then substrate cracking is prevented, but etching solution remains within the cavity
Solution Approach 1:
The patent applies preliminary action by forming through-holes in the cap layer before performing the wet etching process. These pre-formed holes provide drainage pathways that allow etching solution to escape from the cavity during the low-temperature etching process, preventing solution residue while maintaining substrate integrity.
3Loss of substance
If perforations are provided through the cap layer to facilitate etching solution draining, then etching solution residue is reduced, but structural strength of the cap layer decreases
Solution Approach 1:
The patent applies local quality by providing perforations only at specific locations (periphery regions) of the cap layer rather than uniformly across the entire cap. This localized perforation strategy allows etching solution drainage from the cavity while preserving the structural strength of the main cap body. The peripheral holes are strategically positioned to provide drainage function without compromising overall cap integrity.
4Strength
If slow heating and slow cooling are used during thermal processes, then substrate cracking is prevented, but manufacturing productivity decreases
Solution Approach 1:
The patent replaces the thermal field (heating/cooling processes) with a chemical field (low-temperature wet etching process). By substituting the thermal-based cavity formation method with a chemical etching method performed at low temperature, the process eliminates thermal stress that causes substrate cracking while enabling rapid processing that maintains high manufacturing productivity.
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 prevents substrate cracking, improves manufacturing productivity, and ensures structural integrity by minimizing etching solution residue and optimizing the linear expansion coefficient of the cap layer.
Implementation Method 1
a silicon oxide film is formed using a chemical vapor deposition (CVD) process to cover the sacrificial layer
Implementation Method 2
the sacrificial layer is removed using a wet etching process through the holes
Data Source
AI summary
An electronic component comprises a substrate including a main surface on which a functional unit is formed and a cap layer defining a cavity enclosing and covering the functional unit. The cap layer is provided with holes communicating an inside of the cavity with an outside of the cavity. A resin layer covers the cap layer and the main surface and includes one or more bores and a solder layer having a thickness less than a thickness of the resin layer disposed within the one or more bores.