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Some general process trends

This page is supposed to gather some general process trends and good advise for designing IBE recipes. So far these trends has been developed etching Si with resist as masking material and by etcing some multilayered films. The work has been done by Kristian Hagsted Rasmussen @ Nanotech

Etch rate

Etch rate	Parameters
increases with	Beam current
increases with	Beam voltage
increases with	Beam current * Beam voltage
not significantly effected by	Stage angle
not significantly effected by	Accelerator voltage

Etch profile

Etch profile (goal 90dg)	Parameters
improves with	Low stage angle (optimum around 5-10 dg)
is effected by	Beam current (low I(B)(400mA) better than high I(B)(600mA))
is effected by	Accelerator voltage * Stage angle
not significantly effected by	Beam voltage

Rotation speed

The rotation is activated to get a good uniformity over the wafer. The minimum number of rotations to get a good uniformity is 100 rotations for the whole etch. the maximum rotation speed is 20rpm. That means that an etch shorter that 5 min cannot obtain a very good uniformity.

Etch Length [min]	5	6	7	8	9	10	15	20	25	34	50	100
Minimum rotation speed [rpm]	20	17	15	13	12	10	7	5	4	3	2	1