This project belongs to the field of MEMS (Micro Electromechanical Systems). In view of the low cost performance and lack of market competitiveness of MEMS sensors in my country, the invention tries every means to ensure that the structure of the sensor only requires frontal processing, thereby simplifying the manufacturing process, being suitable for large-scale production in integrated circuit factories, and greatly reducing production costs; in addition, it can also realize an all-silicon structure to improve the performance of the sensor, thereby enhancing the market competitiveness of domestic sensors. Starting from this idea, a MEMS sensor based on a front structure was invented and the following invention results were achieved:
1. The invented "silicon box structure"MEMS sensor has become the basic structure of internationally popular MEMS sensors: The "silicon box structure" is cleverly formed in the interior of the silicon wafer through silicon/silicon bonding technology. Using this structure as a sensitive structure, pressure sensors, microresonators and infrared sensors based on the "silicon box structure" are invented. MEMS sensors such as sensors have the advantages of simple manufacturing process, suitable for large-scale production in integrated circuit factories, high sensor yield and good performance, making this structure highly valued by the international MEMS community. Today, it is called Cavity-MEMS (i.e. cavity MEMS) internationally and has become a popular basic structure of MEMS sensors internationally. It is widely used in the design and manufacturing of various MEMS sensors.
2. The invention of the MEMS sensor with a front release structure improves the monolithic integration capability and yield: Taking advantage of the characteristics of corrosion technologies such as isotropic dry etching technology that have low process temperature and little damage to the device, the MEMS sensor based on the front release structure is invented. The sensor is all formed by front processing and is compatible with the integrated circuit manufacturing process. It is suitable for monolithic integration of sensors and circuits and large-scale production in integrated circuit factories, which is conducive to reducing production costs and improving the performance of the sensor.
3. The invented low-temperature and low-stress packaging technology improves the performance of the sensor and realizes the large-scale production of sensors and integrated sensor modules: Aiming at the problem of high-performance and low-cost packaging of sensors, Au-Si, Au/amorphous silicon and Au/Au are used as solder layers, and a Ti adhesion layer is proposed to remove the natural oxide layer on the silicon surface. The low-temperature wafer-level packaging technology is invented, which improves the Au-Si bonding strength and process consistency, which is regarded by international peers as a low-temperature bonding. The development trend of low-temperature bonding. Using this invention, more than ten series of MEMS sensors were packaged and produced, achieving large-scale production.
4. The MEMS sensor invented has achieved large-scale production in an integrated circuit factory, with an average yield of more than 98%, breaking the monopoly of foreign sensors: the MEMS sensor based on the front structure invented in this achievement has the advantages of only requiring front processing and small device area., suitable for large-scale production in an integrated circuit factory, no interface stress, etc., the produced sensor has low cost, excellent performance, and strong market competitiveness. Shanghai Xinmin Microsystems Technology Co., Ltd. has used the results of this invention to produce more than ten series of sensor products in three categories. It has sold more than 30 million sensors in the automotive, medical and environmental testing markets. It is the largest selling MEMS sensor with independent intellectual property rights in China, breaking the monopoly situation of foreign sensors. Since 2011, Shanghai Xinmin has produced/sold more than 18 million MEMS sensors of various types such as pressure sensor chips, pressure sensors, integrated pressure sensor modules, and integrated infrared gas sensor modules, achieving sales of more than 49 million yuan and profits of 4.68 million yuan., with an increase of 4.35 million yuan in tax revenue, and the products sold have created sales of nearly 300 million yuan for users.
5. The achievements of this invention have been cited and evaluated in a series of international colleagues: the achievements of this invention have won 17 invention patents, and 41 SCI/EI papers have been published. He cited them 117 times. Many international colleagues have quoted this achievement extensively in their published papers, giving a good evaluation and having an important impact on the international community. The sensor products produced using the achievements of the invention are comparable to similar international products, some key indicators are better than similar international products, and the achievements have reached the international advanced and domestic leading level.