A getter with a micro–heater for high vacuum packaging of MEMS devices

What is it about?

A getter is necessary for high vacuum packaging of a MEMS device, in order to absorb gases in the cavity left during packaging and released from the materials in usage of the device. The getter needs to be activated before it can absorb the gases effectively; the activation is a process of heating the getter over a temperature for a period of time. Conventionally, the activation is usually done by heating the whole package which may place restrictions on the material and even may influence the performance of the electronic device. In order to solve this problem, we design a structure with the getter fabricated on a floating micro–heater and allow local heating of the getter.

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Why is it important?

The floating structure allows locally heating the getter to its activation temperature by a constant DC supply. For example, in an optimized case an DC supply of as low as 2~4.5 V voltage can raise the getter temperatures to 300~600 °C. This innovative heater-getter unit can be applied to wafer scale vacuum packaging of MEMS devices, effectively improving the stability and reliability of MEMS devices for high vacuum requirement. Since the unit allows multiple activations at desired timing, it can extend the device lifetime by resetting its ambient vacuum to a proper level. The method, easy to implement not only in mass production but also in device operation, can reduce the difficulty of vacuum packaging and promote the development of vacuum packaging technology.

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