Subject: [Fwd: Problem raith SNF 2005-02-15 17:24:20: 20 um aperture scatter when blanked is above spec.]
From: James Conway <jwc@snf.stanford.edu>
Date: Tue, 15 Feb 2005 17:51:16 -0800
Tue, 15 Feb 2005 17:51:16 -0800
Hello:

I CONTINUE TO EVALUATE THE RAITH BLANKER SCATTERING /LEAKAGE VALUES.
Scattering for the 20 um aperture is well above specifications and will 
affect all users writing for extended periods within one writefield such 
as in photoniC crystals and dense patterns.  The distance scattered out 
of a 100 um write field is 185 - 250 microns evidenced on 2% 950K PMMA. 
It is plainly evident after write field alignment that there is excess 
scattering occurring and you can see the contamination artifacts, 
particularly on substrates coated with oxide which easily charge up 
slightly.

Some dot shots exhibit a large annular ring around the shot dot feature 
measuring in 1 - 3 um scales laterally.
This may or may not be evidenced in EBL writing results. I seek users 
reports of the severity of the problem for their EBL writing applications.

Thank you for your support!

James Conway




-------- Original Message --------
Subject: 	Problem raith SNF 2005-02-15 17:24:20: 20 um aperture scatter 
when blanked is above spec.
Date: 	Tue., 15 Feb. 2005 17:24:21 -0800
From: 	jwc@snf.stanford.edu
To: 	raith-pcs@snf.stanford.edu



Today I made further measurements of the blanked emission value or scatter coming down
the column. 
EHT I values:
10 kV, 20 um aperture, 5 mm WD. EHT I values with beam centered in faraday cup at 600X
mag.
Both RAITH and LEO Blanked: 
min 0.0003  max. 0.0006 nA  typically  0.0005 nA
(up from 0.0003 nA observed in past over 100's of measurements.

Raith blanked and LEO unblanked:
min 0.0019 - 0.0021 typically 0.0020 nA

Raith unblanked and LEO unblanked 0.0693 nA and stable.
This is scattering at 2.88% level when the specification is less than 0.5% emission
when blanked of the Beam I total value unblanked.
OUT OF SPECIFICATION FOR THIS APERTURE.
JWC 02152005:17:25:00



Hello:

I CONTINUE TO EVALUATE THE RAITH BLANKER SCATTERING /LEAKAGE VALUES.
Scattering for the 20 um aperture is well above specifications and will affect all users writing for extended periods within one writefield such as in photoniC crystals and dense patterns.  The distance scattered out of a 100 um write field is 185 - 250 microns evidenced on 2% 950K PMMA. 
It is plainly evident after write field alignment that there is excess scattering occurring and you can see the contamination artifacts, particularly on substrates coated with oxide which easily charge up slightly.

Some dot shots exhibit a large annular ring around the shot dot feature measuring in 1 - 3 um scales laterally.
This may or may not be evidenced in EBL writing results. I seek users reports of the severity of the problem for their EBL writing applications.

Thank you for your support!

James Conway




-------- Original Message --------
Subject: Problem raith SNF 2005-02-15 17:24:20: 20 um aperture scatter when blanked is above spec.
Date: Tue., 15 Feb. 2005 17:24:21 -0800
From: jwc@snf.stanford.edu
To: raith-pcs@snf.stanford.edu


Today I made further measurements of the blanked emission value or scatter coming down the column. 
EHT I values:
10 kV, 20 um aperture, 5 mm WD. EHT I values with beam centered in faraday cup at 600X mag.
Both RAITH and LEO Blanked: 
min 0.0003  max. 0.0006 nA  typically  0.0005 nA
(up from 0.0003 nA observed in past over 100's of measurements.

Raith blanked and LEO unblanked:
min 0.0019 - 0.0021 typically 0.0020 nA

Raith unblanked and LEO unblanked 0.0693 nA and stable.
This is scattering at 2.88% level when the specification is less than 0.5% emission when blanked of the Beam I total value unblanked.
OUT OF SPECIFICATION FOR THIS APERTURE.
JWC 02152005:17:25:00