Page 378 - Microsensors, MEMS and Smart Devices - Gardner Varadhan and Awadelkarim

358 IDT MICROSENSOR FABRICATION

for postdeposition cleaning. Once the 15 minute postdeposition cleaning is completed,
the plasma is extinguished, the gases are turned off, and the chamber is evacuated for
3 minutes. Finally, a robotic transporter can shuttle the SAW-IDT wafers to the load-lock
chamber (unit 3), where they are subsequently removed.

12.4 CONCLUDING REMARKS

This chapter has described in detail two process runs that can be followed to fabricate a
Rayleigh wave IDT microsensor or a Love wave IDT microsensor (Gangadharan 1999).
The main steps for the etching process are given in Table 12.2 and for the lift-off
process in Table 12.3. These tables provide the reader with a list of the key steps of the
two processes described in Section 12.2.4 earlier.
A summary of the main advantages and disadvantages of the etching and lift-off
processes is given in Table 12.4. They are relevant to the fabrication of SAW-IDT
microsensors and are taken from a number of sources (Campbell 1996, 1998; Atashbar
1999).
The next chapter describes the use of SAW-IDT devices in a number of different
sensing applications.

REFERENCES

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cations, Academic Press, London.
Campbell, A.S. (1996). The Science and Engineering of Microelectronic Fabrication, Oxford Uni-
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Campbell, C. (1998). Surface Acoustic Wave Devices and their Signal Processing Applications,
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