RE: Data Needed for Custom
HEBS-Glass Masks
Dear Canyon Materials, Inc. Customer,
To facilitate the preparation of
the necessary data that CMI needs to make you a customized HEBS-Glass gray
scale photomask, we recommend the following:
(1) Customers need to
first determine the relationship of developed photoresist thickness with
optical densities in a HEBS-glass plate. This can be accomplished
by using a HEBS-glass calibration plate. Please read the CMI info
sheets, "Why Use a HEBS-Glass Calibration Plate"
and the description of the HEBS-Glass Calibration
Plate that is most suitable for your application (HEBS5, I85B, or 3Q3BL). Another CMI info sheet,
"The Photoresist Analog Transfer Scheme for
HEBS-Glass Photomasks" is useful to establish your photolithographic process.
(2) Next, a GDSII data
file of your desired mask needs to be prepared.
CMI offers the services of creating your GDSII files for the following types of mask patterns: gratings and microlens arrays. If your mask pattern is composed of mainly these types, you can send us a drawing of your design specifications and we will work with you to prepare a GDSII file that meets your particular specs. Please also review CMI Product Information No. 01-88, page 7 of this document in particular.
Otherwise, we need to receive a GDSII data file of your mask pattern from you together with the drawing of your mask layout.
(3) Also, send us the optical density values corresponding
to the desired gray levels. These optical densities should have been
determined in the previous step with a calibration plate.
Once we have received the above described
information, we can make a firm quotation. The cost of fabricating an HEBS-glass
customized gray scale mask depends on the e-beam write time and data fracture
time. The e-beam write-time depends on a number of factors including
the number of gray levels and the size of the mask pattern. We fracture
the GDSII data files that our customers give us into primitive shapes that
the e-beam writer can write. The time it takes to fracture GDSII
data files into primitive shapes depends on a number of factors including
the size of the repeating unit. When there is no repeating unit,
the entire pattern has to be fractured and the fractured BPD data files
could be more than a gigabyte for a 0.25" X 0.25" pattern.
We hope this helps to clarify the
necessary steps involved in ordering a custom-designed HEBS-glass gray
scale photomask. Good communication of design and layout parameters
is important so we encourage much correspondence with customers during
this process. At any point in the process, we would be happy to offer
our assistance and feel free to contact us if further clarifications are
needed.
