[Spm] Cleaning grating TGT-01

[Rostislav V. Lapshin]

Hello Christopher, hello Colleagues!

To remove organic impurities, an oxygen RF-plasma (13.56 MHz) can be used. In particular, I am using a machine for plasmachemical treatment of wafers Plasma 600 (Research Institute of Semiconductor Engineering, Russian Federation). Such machines are used in microelectronic processing, for example, for photoresist removal. Instead of oxygen, filtered room air can be used. Process parameters depend on type and degree of impurities.

Typical parameters when using air (RH 50-60%):
- residual pressure in the process chamber 0.5-1 Torr
- current 30-100 uA (corresponds to approx. power 120-400 W)
- anode current of the RF-tetrode 0.4-0.8 A
- treatment time 1-5 minutes

To remove, beside organic, more firm formations - solid particles, oxide films, etc., surface bombardment by Ar ions can be used. I particularly use ion coater IB-3 (Eiko Engineering, Co., Japan). Similar coaters are used frequently in SEM for sputtering thin metal films on nonconducting samples.

Typical parameters of the process using Ar (99.99%):
- residual pressure in the process chamber 0.2 Torr
- glow discharge current 3 mA (accelerating voltage on cathode is equal to about 420 V)
- treatment time 1-3 minutes

When removing impurities, to avoid removal or damage to the structure itself, the process parameters of treating in Ar-plasma should be adjusted. I would recommend to start with short times and small currents (accelerating voltages), gradually increasing them until the required values are found. The operation sequence can be as follows: treat sample; check results, first, with an optical microscope, then with an ACM or SEM; change parameters; treat again and so on.

Hope that helps. Feel free to contact me offline, if necessary.

Best regards,
Rostislav Lapshin

Rostislav V. Lapshin, Ph. D.
Staff Scientist
Solid Nanotechnology Laboratory, Nanoelectronics Department
Institute of Physical Problems named after F. V. Lukin
State Scientific Center of Russian Federation
Zelenograd, Moscow, 124460
Russian Federation

tel (lab): +7 (499) 736-9379, 736-9324
tel (office): +7 (499) 731-9843
fax (office): +7 (499) 731-5592, 731-4656

pri email: rlapshin at yahoo.com
sec email: rlapshin at gmail.com

web: http://www.niifp.ru/staff/lapshin/en/
http://www.nanoworld.org/homepages/lapshin/


----- Original Message ----- 
From: "Chris Honig" <cdhonig at vt.edu>
To: spm at spmlist.di.com
Subject: Cleaning grating TGT-01
Date: Tuesday, September 1, 2009 4:40 AM

To whom is may concern,
We have a TGT-01 reverse tip grating of Si spikes that are about 750nm high, spaced on a 2-D grid at about 3 um separation. The grating has gradually accumulated dust and other crud over many years of use and it's ability to image spheres on cantilevers is steadily getting worse. Do you have a good procedure for cleaning this grating?

Thanks,
Chris Honig.

Christopher Honig

Ducker Group
Department of Chemical Engineering
141 Randolph Hall
Virginia Tech
Blacksburg VA 24061 USA

Email: cdhonig at vt.edu