A Sapphire Wafer Direct Bonding Method And Process For A Sapphire Pressure-sensitive Structure

1. The present invention belongs to the technical field of mems technology, in particular to a method for direct bonding of sapphire wafers of a sapphire pressure-sensitive structure.

Background technique:

2. The operating temperature of traditional semiconductor pressure sensors is generally below 600°C. The maximum operating temperature of the sic piezoresistive pressure sensor is 600°C, the maximum operating temperature of the soi pressure sensor is below 500°C, and the maximum operating temperature of the silicon-sapphire pressure sensor. Temperature 350℃. Electrical pressure sensors are difficult to apply in higher temperature environments.

3. At present, fiber optic pressure sensor products based on sapphire chips have appeared abroad, such as the wave-phire dpt950 fiber optic pressure sensor of British oxsensis company, the maximum working temperature can reach 600 ℃, and the probe front end can reach 1000 ℃. However, the research results of optical fiber pressure sensors based on sapphire chips have not been reported in China. Chinese patent document cn103234673 discloses a high temperature-resistant pressure sensor micro-nano structure, which includes: a silicon carbide diaphragm, a reflective film, a semi-reflective film, a bonding layer, a silicon carbide substrate, an encapsulation layer and a sapphire optical fiber; the reflective film is coated on In the middle of the silicon carbide diaphragm, the semi-reflective film is coated on the end of the sapphire fiber, the bonding layer (silicon dioxide) is located between the silicon carbide diaphragm and the silicon carbide substrate, and the sapphire fiber is connected to the silicon carbide substrate through the encapsulation layer (high temperature ceramic glue) . The preparation process of the above pressure sensor is to form a Fabry-Parot interference cavity by using a reflective film plated on a silicon carbide diaphragm and a semi-reflective film plated on the end of a sapphire optical fiber to realize pressure detection in a high temperature environment.

4. At present, the domestic sapphire wafer (wafer-level) direct bonding process is still in the theoretical research stage, and there is no mature sapphire wafer (wafer-level) direct bonding process technology yet. In China, wafer-level bonding is usually aimed at silicon-based materials, and the bonding temperature is below 500 °C, such as silicon-silicon bonding, silicon-glass anodic bonding, etc. Chinese patent document cn 105236350 a discloses a direct bonding method for sapphire pressure-sensitive chips, only the temperature is 1350°C, no pressure (pressure) control during the bonding process, and no coupling control of temperature and pressure.

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