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Shahram56 (Materials)
2 Feb 04 6:29
I would like to know about the mask design and software used for designing the mask. At the moment we are using diode mask the simplest mask possible with the back side electrode. I need to redesign the mask and provide the design for fabrication. I would appreciate if any body have any information on this issue.
I remain.
Thank in advance.
IRstuff (Aerospace)
2 Feb 04 10:56
Depends on how much you want to spend, etc., etc.

>  The lowest tech approach is to draw the design of the layout on gridded mylar at 1270x or some nice multiple converting from metric to english dimensioned mylar.  Then, you can send the layout to a digitizing house, who will convert it to the appropriate format for mask generation, which depends on your specific process and equipment, e.g., contact, 1x, 5x, 10x, pos/neg, +/-compensation.

>  Lowest overall cost, which we did in a college lab, was to do each layer in black/white and used a copy camera for 10x reduction.  Obviously, only suitable for onesy-twosy.

>  Buy GDSII compatible layout program/design system and do it all yourself on the computer.

TTFN

Shahram56 (Materials)
3 Feb 04 0:24
thank you for the comment.
Two question left for me?
1- what is the appropraite softwarecompatible with GDSII
2- where can i get appropriate sources regarding mask design?
I remain
IRstuff (Aerospace)
3 Feb 04 2:38
I haven't dealt with IC layout in a while, but there are many workstation-based systems that do layouts.  If you do a websearch on "gdsii layout" you'll get a number of hits for anything from PC-based to workstation-based as well design services.

What type of sources are you refering to?  If you are refering to expertise in layout, the above websearch will gather various companies specializing in IC design and layout.

TTFN

Shahram56 (Materials)
3 Feb 04 3:03
I just want to design simple diode mask and very simple features on that in the first step. We haev the diode mask in the lab but i want to modify it. I can use the Autocad but I want to know more about the design and layout of standard laboratory mask. If it work I will go for trasistros?
I remian
IRstuff (Aerospace)
3 Feb 04 11:00
a>  Autocad will work from the perspective of drawing features, I'm personally not familiar with whether ther's a Autocad to GDSII conversion, which would be necessary to get masks.

b>  MOS transistors are readily possible, since most of your existing fab process is probably very compatible with MOS transistors, although, without ion-implanted junctions and polysilicon gates, you'll wind up with metal-gate devices with about 6 um gate lengths.

Bipolar transistors is whole other ballgame, although you can obviously make lateral devices, but they generally have very pathetical gain.  Vertical transistors with high gain require buried layer/epi processes, ion implantation, etc.

TTFN

phototool (Computer)
4 Aug 04 23:36
There are multiple translators from for DXF to GDSII as well as other file formats. If you are interested in these products I have experience with a few of them as I have been involved with these types of conversion for about 15 years. Just let me know and I can point you in the write direction.
Merciless (Electrical)
2 Sep 04 12:02
Hi Phototool,

Could you share with us some of your experience with DXF to GDSII?  I am working on a non-VLSI design with donuts and some non-retanglar shapes by using AUTOCAD-type tool and would like to convert it to a GDSII format to incorporate it to be a part of larger mask design.  Thanks.

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