[labnetwork] Cleanroom humidity

[Demis D. John]

FYI, to Yong Sun's point, here is our Litho process control data for what
Peder mentioned is 50±10% humidity in our CR:
https://wiki.nanofab.ucsb.edu/wiki/Process_Group_-_Process_Control_Data#Lithography_(Process_Control_Data)
(Note in July 2025 the beam delivery optics were replaced causing a sudden
jump in average CD.  Approx ~30 peak-to-peak CD variation - I assume some
of that is intern SEM measurement variation.)

-- Demis (contact info <https://wiki.nanotech.ucsb.edu/wiki/Demis_D._John>)
*Reminder*: The NanoFab has a publications policy
<https://wiki.nanotech.ucsb.edu/wiki/Frequently_Asked_Questions#Publications_acknowledging_the_Nanofab>


On Wed, Dec 17, 2025 at 5:00 PM Sun, Yong <yong.sun at yale.edu> wrote:

> Cleanroom humidity should be maintained at 45% +/- 5%, temperature should
> be 68F +/- 1F. Ideally, the temperature/humidity level in Cleanroom should
> not fluctuate over time.
>
> The cleanroom tools/capabilities can start having issues if the
> temperature & humidity drift out of spec:
> (i) Optical lithography could suffer from temperature fluctuation, e.g.
> patterns on the wafers/masks can shrink/expand due to thermal expansion,
> leading to alignment issues
> (ii) Too much moisture in the cleanroom air could lead to resist adhesion
> problem, too little moisture in the cleanroom air could lead to ESD problem.
> ------------------------------
> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Peder
> Lenvik <plenvik at ucsb.edu>
> *Sent:* Wednesday, December 17, 2025 5:04 PM
> *To:* Alex Dixon <agdixon at mines.edu>
> *Cc:* Lab Network <labnetwork at mtl.mit.edu>
> *Subject:* Re: [labnetwork] Cleanroom humidity
>
> 40 to 60
> Or 50 +/- 10
>
> Peder Lenvik
>
> Sr. Facilities Lead
>
> Electrical and Computer Engineering
> E.S.B. Bldg. #225, Room 1109F
> University California Santa Barbara, Santa Barbara, Ca. 93106
>
>
> On Wed, Dec 17, 2025 at 14:03 Alex Dixon <agdixon at mines.edu> wrote:
>
> For those of you with climate controls in your cleanrooms, what relative
> humidity do your keep your cleanroom at, and how tightly do you control the
> fluccuations?  How significant an effect have you seen on device
> performance?
>
> Our campus facilities is doing a climate control audit and asking any lab
> with special requirements to justify them. Any info you could share would
> be appreceated.
>
> Thanks!
> -Alex
>
> __________________________________________________________
>
>
> Alex Dixon, Ph.D. (He/Him)
> Lab Manager
> Nanofabrication and Thin Film Deposition
> Shared Instrument Facility
> Colorado School of Mines
>
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