[libre-riscv-dev] [Libre-silicon-devel] [OT only slightly] STEAM Camp OpenSourceEcology 22jan2020 for 9 days

David Lanzendörfer leviathan at libresilicon.com
Tue Dec 31 13:15:39 GMT 2019

Hi Pavel

One one micron mask set can cost between two thousand US dollar and
upwards (depending on the amount of layers), but this cost will increase
drastically as soon as you go below one micron.

Additionally there are multiple draw backs about mask sets which could
be eliminated when using a mask less lithography system.

For instance, you only can expose one pattern using a stepper, and even if
you only have a hand full of prototypes to manufacture, you will still end
up paying the costs for the mask sets, even if you do only one single wafer.

In addition the loading and unloading of the masks into the stepper aligner
is time consuming.

Having a display just switch between layouts during exposure allows for an
arbitrary amount of prototype chips without the need for manufacturing masks.

This BTW also reduces another attack vector from Andrew (Bunnie) Huang,
which he mentioned during his congress talk.


On Tuesday, 31 December 2019 8:38:25 PM HKT pavel at noa-labs.com wrote:
> Are 1um masks that expensive (compared to the rest of setup)? Or is it has
> more to do with turnaround times?
> Can you share details of a light source and resist? One important thing will
> be to pick light source that will not burn the LCD matrix, and will not be
> absorbed by the glass much. Making a custom made LCD with special materials
> might not be that cheaper that sticking with masks for the beginning.
> It will be truly great if one can just replace the mask with LCD with no
> extra work

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