Subject: Re: e-beam help?
From: Hendrik Bluhm <hendrikb@stanford.edu>
Date: Fri, 29 Aug 2003 01:22:32 -0700 (PDT)

Charis,
I think Pos 1 and 2 is the offset between the LL corner of your working
area and the point whose coordinates ae given in the positionlist.
Thus, they are normally 1/2 WF size. However, if you change the WF
size after copying the entries into the positionlist, this is no longer
true.

Another possibility is an offset between the LEO image and the Raith
coordinates - I always scan with the Raith software if alignment is
important. Finally, the WF alignment may easily offset your UV system by
up to a few micron - to avoid problems with this, either make sure you see
the feature you use for WF alignmet exactly at the current stage position,
i.e. the center of a full EF scan with the Raith software when creating
the marks, or do the 3-point alignment again after the WF alignment. To
get a good WF alignment, you should probably also do the 3-point alignment
before to get the scale factors and rotation right.

Hendrik

On Fri, 29 Aug 2003, Charis Quay Huei Li wrote:

> Hi guys,
>
>      I had problems with my alignment a couple of days ago and was
> wondering if you have any clues. Things were just offset. No rotation or
> scrunching. I suspect that there are things in the positionlist that I
> don't understand that are causing this problem. I did make sure that U and
> V were in the centre of my first writefield, but I don't really know what
> htings like Attribute and pos1/2/3 mean. Do you? I think I'm going to call
> Raith tomorrow. Thanks.
>
> Cheers,
> Charis.
>
>
>

---------------------------------------------------
Hendrik Bluhm
Department of Physics
Stanford University

Work adress:                    Moler Lab
           			Lab. for Advanced Materials
Phone: (650) 723-4012           McCullough Bldg.
Fax:   (650) 725-2189           476  Lomita Mall
                                Stanford, CA 94305