“MEMS technology is currently one of the most widely used technologies, and everyone must know something about MEMS. In order to enhance everyone’s understanding of MEMS, this article will introduce MEMS based on two points: 1. Four types of MEMS foundries, 2. Qualcomm MEMS packaging technology analysis.
MEMS technology is currently one of the most widely used technologies, and everyone must know something about MEMS. In order to enhance everyone’s understanding of MEMS, this article will introduce MEMS based on two points: 1. Four types of MEMS foundries, 2. Qualcomm MEMS packaging technology analysis.
1. Four types of MEMS foundries
MEMS (Micro-Electro-MechanicalSystems) is a micro-device or system that integrates micro-mechanical structure, Electronic circuit, micro-actuator, and communication, which can be produced in batches. It has small size, low cost, low power consumption, easy integration and intelligence. Features. MEMS is developed with the development of semiconductor integrated circuit microfabrication technology and ultra-precision machining technology. Different measured physical quantities form different types of MEMS sensors and are used in different fields.
Each MEMS foundry company has its own unique advantages, different MEMS foundries, different starting lines. Generally speaking, different strategies are adopted to attract customers with their own characteristics. MEMS foundries can be roughly divided into four types: 1. Provide MEMS foundry services to silicon wafer foundries 2. MEMS foundries of OEM suppliers 3. MEMS foundries of IDM 4. Pure MEMS foundries.
From the point of view of 1 and 2 foundry types, MEMS foundry chooses IDM or OEM for their own advantages and disadvantages. IDM has been in development for 20 to 30 years, but the intellectual property security issues that customers care about have not been well resolved. Therefore, for foundries, they should focus on processes and customers. Pure MEMS foundry companies can handle multiple processes and multiple customers at the same time, which is the most flexible model.
Different types of MEMS foundry have their own differences in technology. In most cases, MEMS chips and ASIC chips are manufactured separately, and then integrated through a system-in-package or bonding process. For designers, the flexibility of package integration is greater. And some MEMS foundries provide MEMS-CMOS technology, which can integrate two chips into a single chip. Its advantages are: reduced power consumption, high speed and low parasitic effects. The trade-off is the increase in manufacturing complexity and the reduction in thermal budget.
In order to adapt to the rapid development of the market, MEMS foundry companies can also provide a variety of stacking technologies, such as 3DTSV, 2.5D interposer and so on. In the past, MEMS foundry corresponded to products in the industrial market, and with the booming electronics market, the demand for MEMS foundry is also increasing. This has also prompted MEMS foundry products to become smaller and smaller in size and cost.
2. Qualcomm MEMS packaging technology analysis
The deployment of MEMS devices in commercial products requires that these devices provide the required functions, but also requires the existence of suitable packaging technologies to package these devices in a robust and commercially appropriate manner. Designing the packaging of MEMS devices is often more complicated than designing the packaging of ordinary integrated circuits. This is because engineers often have to follow some additional design constraints and meet the requirements of working in harsh environmental conditions.
In terms of MEMS packaging methods, Qualcomm applied for an invention patent called “MEMS packaging” as early as 2016 (application number: 201680019494.5), and the applicant was Qualcomm Technology International Co., Ltd.
The above figure is a cross section of the packaged MEMS device 100. Specifically, the package 100 forms an intermediary structure between the circuit board 101 and other electronic components 102. This arrangement allows the device to serve as a redistribution and mounting layer for the electronic component 102. A pad 103 is provided on the bottom side of the package 100, and the package can be electrically connected to the circuit board 101 through solder balls 104. A pad 105 may also be provided on the upper side of the package 100, and the pad 105 is mainly used for mounting the electronic component 102.
The package 100 mainly includes three layers of materials: 109, 110, and 111. A recess 112 is formed on the upper surface of the lower layer 109. Both the lower layer and the upper layer may be formed of a glass material, and the spacer layer may be formed of the same material (e.g., silicon) as the MEMS component.
The MEMS component 114 is fixed between the lower layer 109 and the upper layer 111 at its proximal end. The lower layer 106, the spacer layer 113, and the upper layer 111 together form a package with cavities 112, 115 so that the distal end of the MEMS component 114 can move in the cavity. In addition, the MEMS component 114 can also provide various functions. For example, the component can be an accelerometer or an energy harvester, or a piezoelectric element can be provided on this component to convert kinetic energy into electrical energy, and so on.
During manufacturing, the cavities 112, 115 may be filled with inert gas and/or evacuated to provide a reduced pressure environment. This environment can improve the performance (by reducing the resistance to movement) and lifespan (by controlling the environment) of MEMS components.
Micro-sensors, micro-actuators, micro-components, micro-mechanical optical devices, vacuum micro-electronic devices, power electronic devices, etc. made with MEMS technology are used in aviation, aerospace, automotive, biomedicine, environmental monitoring, military and almost people There are very broad application prospects in all fields.
However, there is a certain gap between the development of my country’s MEMS technology and the level of foreign countries. Regardless of the scale and type, as well as the specific products, we need to face this gap, use policy dividends, and develop the MEMS industry chain based on the development of specific products to realize China “Intelligent Manufacturing”!
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