Low-temperature glass solder bonding and encapsulating method based on disc level glass micro-chamber

Abstract

The invention discloses a low-temperature glass solder bonding and packaging method based on wafer-level glass microcavities, which comprises the following steps: firstly, utilizing a silk-screen printing process to coat low-temperature glass solder on a packaging contact part of a Pyrex7740 glass substrate provided with a microcavity structure, preliminarily drying the low-temperature glass solder, and making the low-temperature glass solder be cured and cling to the Pyrex7740 glass substrate provided with the microcavity structure; secondly, aligning a Pyrex7740 glass packaging wafer which is cured with the low-temperature glass solder and a silicon substrate wafer comprising an MEMS device or a CMOS circuit, and making the microcavity structure on the Pyrex7740 glass substrate correspond to the position of the MEMS device or the CMOS circuit to be packaged of a silicon substrate; and thirdly, using a clamper to firmly clamp the two aligned wafers, applying the pressure, sintering the glass solder in a specified packaging atmosphere, and cooling the glass solder. The whole process is based on integral processing of the silicon wafer and the Pyrex7740 glass wafer, belongs to a process for manufacturing and packaging a wafer-level MEMS, and has the characteristics of simple method, adjustable packaging space and low cost.

Description

technical field [0001] The invention relates to a MEMS (micro-electro-mechanical system) manufacturing and packaging technology, in particular to a low-temperature glass solder bonding packaging method based on a wafer-level glass microcavity. Background technique [0002] In the field of MEMS manufacturing technology, Pyrex7740 glass (a kind of glass containing alkaline ions, Pyrex is the product brand of Corning Company) is an important material, it has the same semiconductor silicon material (at room temperature 300K, the thermal expansion coefficient of Pyrex7740 glass is 28 ×10 -7 / K, the thermal expansion coefficient of silicon is 23~40×10 -7 / K) similar thermal expansion coefficient, high light transmittance and high strength, can be used for high-strength anodic bonding with silicon, and can also be integrated with silicon substrates by metal solder bonding or polymer bonding. chip bonding. Due to such characteristics, Pyrex7740 glass is widely used in MEMS packag...

AI Technical Summary

Problems solved by technology

[0005] If a Pyrex7740 glass substrate containing a glass microcavity is used, and anodic bonding is used to perform wafer-level packaging of the device, the process requires high flatness of the bonding surface, and the MEMS device substrate that generally adopts surface micromachining technology cannot meet the requirements.

Moreover, because the process introduces a bonding voltage of more than 400V, it is easy to cause irreversible damage to the movable parts of the micro-nano size of MEMS

[0006] Nowadays, using metal solder bonding or polymer bonding technology, most of them use a whole piece of silicon substrate without microcavity structure or Pyrex7740 glass substrate to bond with the substrate wafer containing the device, only supported by the bonding solder layer The height of the packaging space is very limited, and the height is only about 1-6 μm, which is very easy to damage the devices on the substrate.

Moreover, the bonding solder layer and the silicon substrate tend to have a large thermal mismatch, which is prone to failure, so that the hermetic package fails, and its package reliability is very poor.

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