====== Photolithography ======

The ECE Cleanroom in Owen has a mask aligner and photolithography processing stations available for use. Proper training must be received prior to using the equipment (see Chris Tasker). 

Photolithography masks can be created via a laser writing tool (also in the cleanroom). Smallest feature size is approximately 500 nm. Chrome/Quartz mask blanks run approximately $60. Laser time costs money due to the finite life of the tool and the cost of laser gas. Direct write lithography is also available. 

[[http://www.microchemicals.eu/technical_information/TroubleShooter_EN.pdf|Lithography Troubleshooter - Microchemicals (2012)]]

====== Shadow Masks ======

Shadow masks for depositing films and wires have been made with the help of Todd Miller (rtm at oregon state dot edu) at the [[http://mbi-online.org/|MBI]] (Microproducts Breakthrough Institute on HP campus).  Pre-2011 was Jack Rundel, who has left MBI.

We have created masks out of 50um 304SS flat shim stock and 75um 316SS shim stock. Other materials are available for use.  Drawings should be made in a CAD program that can export to DXF (SolidWorks, AutoCAD, etc); one free option is DraftSight, a 2-D program from the makers of SolidWorks.

The tool used to cut the masks is the ESI5330 UV Laser Drill. The cutting path of the drill is controlled by relatively simple "G code." [[http://www.solidworks.com/|SolidWorks]] can be used to create more complex models that can be converted into G code at MBI. Guest workstations with SolidWorks and other programs are available for use. Jack has a great {{:mask:importing_part_from_solidworks_to_smartcam_08-2010.pdf|step by step guide}} on how to properly export the models and get the data to the drill. 

For the shim stock, the average line width is about 50um, although 20um lines have been achieved. 

===== G Code for the ESI5330 =====


Example G code that describes a 10mm square within a 30mm square. All coordinates are shown in micron units. The internal features cut first. The part perimeter cuts last.
"G0" = move to this point without cutting
"G1" = move to this point while cutting

<code>
%
(ESI5330)
T1 6
T0 221

*** internal features ***
P0
G0 X10000.0 Y10000.0
G1 X20000.0
   Y20000.0
   X10000.0
   Y10000.0
P1


*** part perimeter ***
P0
G0 X0.0 Y0.0
G1 X30000.0
   Y30000.0
   X0.0
   Y0.0
P1
%
</code>

The following is the G code for an example of a shadow mask made for 3-omega measurements. 

<code>

%
(ESI5330)
T1 6
T0 221


P0

G0 X3000.0 Y1960.0
G1 Y2000.0
 Y4000.0
 X5000.0
 Y2000.0
 X5980.0
 Y10000.0
 X5000.0
 Y8000.0
 X3000.0
 Y10000.0
 Y10040.0
 X9000.0
 Y10000.0
 Y8000.0
 X7000.0
 Y10000.0
 X6000.0
 Y2000.0
 X7000.0
 Y4000.0
 X9000.0
 Y2000.0
 Y1960.0
 X3000.0


G0 X9500.0 Y6000.0
G3 I9000.0 J6000.0


G0 X7500.0
G3 I7000.0 J6000.0


G0 X5500.0
G3 I5000.0 J6000.0


G0 X3500.0
G3 I3000.0 J6000.0

P1

P0

G0 X12000.0 Y0.0
G1 X0.0

G0 X12000.0 Y12000.0
G1 Y0.0
	

G0 X0.0 Y12000.0
G1 X12000.0

G0 X0.0 Y0.0
G1 Y12000.0

P1
%

</code>