[labnetwork] Metallization on rough ceramic substrates

[mdwyer87 at gmail.com]

Hi Adithi,

 

In addition to the good advice already given, you might also consider thermal issues if your problem is the metal not lifting off. Evaporating Pt (especially up to 250 nm) can result in significant substrate heating, particularly if your samples are not heatsinked. I clamp my samples to a large block of aluminum flattened on a surface plate and that solved my thermal issues (along with sensible deposition rates).

 

Matt

 

Postdoc

van der Weide Group

UW-Madison

 

From: labnetwork-bounces at mtl.mit.edu <labnetwork-bounces at mtl.mit.edu> On Behalf Of Noah Clay
Sent: Friday, January 4, 2019 1:17 PM
To: ADITHI U <uadithi at iisc.ac.in>
Cc: labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] Metallization on rough ceramic substrates

 

Hello Adithi,

 

As you know, ceramics can be quite porous and metal adhesion can be diminished by surface/internally adsorbed water, organics, etc. Therefore, you may consider deep solvent cleaning, other surface treatments as appropriate (e.g., plasma) for your material and a lengthy dehydration bake prior to resist application.  If pre-resist cleaning proves ineffective, then after resist development, you may consider O2 plasma or, if available, in-situ ion bombardment.  Lastly, given the rough topography of your substrate, there may be undeveloped or underexposed pockets of resist on the substrate, which necessitate optimizing bake, exposure and develop conditions.

 

As for HMDS (mainly used for Si), without knowing the type of ceramic you’re using, I can’t say that it will be effective as an adhesion promoter.  I very humbly/respectfully disagree with previous comments that HMDS is used mostly for etching, but agree that to facilitate liftoff, a relatively thick LOR layer should be spun and baked before application of imaging resist.

 

Best,

Noah Clay

 

Singh Center for Nanotechnology 

University of Pennsylvania 

Philadelphia, PA

Sent from my iPhone


On Jan 4, 2019, at 08:51, Hitesh Kamble <hit.kamble at gmail.com <mailto:hit.kamble at gmail.com> > wrote:

Hello Adithi,

 In case of HMDS ,it will improve adhesion but resists will not remove easily from surafce.HMDS is mostly use in etching. Since you're having rough surface, Instead of HMDS use LOR 3B or say liftOFF resists which helps to improve liftoff process.

Also for 250nm metallization you need more than 2um thick resists.

 

We did not do this on ceramic samples exactly but successfully did liftoff on etched/textured glass and etched samples(roughness more than~400nm).

Following are my suggestions:

-Time  Interval between litho and deposition should be lowest as possible

- Dehydration at higher temp and for longer time.

-LOR 3B coating at lower rpm and gradually increase rpm.

-Keep sample in Remover PG and heat at 80C for 5min or more if metal not lifted,(Sonication not recquired in most cases)

 

 

Thanks,

Hitesh Kamble

IITBNF-IIT Bombay

 

 

On Fri 4 Jan, 2019, 6:08 PM ADITHI U <uadithi at iisc.ac.in <mailto:uadithi at iisc.ac.in>  wrote:

Dear All,

 

      We are having difficulties in doing metal(Ti/Pt) lift off on ceramic substrates. Does any of you have experience on fabricating metal patterns on the rough Ceramic Substrates. Below are the details of the process done.

 

   The roughness of the ceramic substrates were approximately 400nm. We had used HMDS as adhesion promoter for lithography, the thickness of the Photoresist was ~ 1.5um.The thickness of the Ti/Pt layer was ~ 250nm.  Immediately after lithography the deposition was done  followed by 48 hours of lift off(Acetone) process. Ultrasonication(5-10mins) in Acetone was done after 48hours. 

Best Regards


Adithi.U
Senior Facility Technologist,
National Nano Fabrication Centre,
CeNSE, Indian Institute of Science
Bangalore

 

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