[labnetwork] Glow around metals during ebeam evaporation

Wed Apr 16 13:48:50 EDT 2025

It sounds like there might be extra cooling occurring when higher power is needed for evaporation. This could overheat the ebeam assembly, including the two magnet plates on the sides, leading to an offset of the sweep center. Just a thought.

Bangzhi
Penn State Nanofab

________________________________
From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Rob Belan <robb at lesker.com>
Sent: Wednesday, April 16, 2025 5:02:25 AM
To: Chris Cott <Chris.Cott at nanomelbourne.com>
Cc: labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
Subject: Re: [labnetwork] Glow around metals during ebeam evaporation

Hi Chris,

I would sand the copper cover as well.  If insulating material covers the copper parts of the e-gun charging can happen.  But the liners you are using should be good.  Check the ground for the system.  You need to have a good ground – that is important.  Make sure you are not oxidizing your materials with quick vents after deposition.  If you use spacers under the crucible liners it takes time for the material in the liner to cool down.

Take care.

Rob

Rob Belan

Technical Director PVD Products

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From: Chris Cott <Chris.Cott at nanomelbourne.com>
Sent: Tuesday, April 15, 2025 8:13 PM
To: Rob Belan <robb at lesker.com>
Cc: labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] Glow around metals during ebeam evaporation

You don't often get email from chris.cott at nanomelbourne.com<mailto:chris.cott at nanomelbourne.com>. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification>

Hi Rob,

Thanks for the reply!

We suspected charging but couldn't figure out the cause. We use a Mo crucible liner for the Ag and a graphite one for the Cu. Is it possible that, because the materials don't wet to the crucibles, there is poor conductivity between the material and the crucible? As a first step I'll try sanding the pockets to make sure the crucible liners and pockets have good contact.

Warm regards,

Chris.

-------------------------------------------------------------------------------------------
Chris Cott     BAppSc, BSc, PhD.

Process Engineer,

Melbourne Centre for Nanofabrication

151 Wellington Road, Clayton  3168

Victorian Node of the Australian National Fabrication Facility

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On Tue, 15 Apr 2025 at 23:20, Rob Belan <robb at lesker.com<mailto:robb at lesker.com>> wrote:

Hi Chris,

What kind of crucible liner are you using for the metals?  It sounds like you are using an insulating crucible liner like Al2O3?  If so, you are not allowing the electrons to ground out.  This can then cause charging effects that you may be seeing.  Try switching to an electrically conductive crucible liner and this problem should go away for the metals.

Take care.

Rob

Rob Belan

Technical Director PVD Products

Tel: +1 (412) 387-9200 x7378<tel:+1%20(412)%20387-9200%20x7378>

| Cell: +1 (412) 398-1275<tel:+1%20(412)%20398-1275>

| Fax: +1 (412) 233-4375

| Email: robb at lesker.com<mailto:robb at lesker.com>

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From: labnetwork <labnetwork-bounces at mtl.mit.edu<mailto:labnetwork-bounces at mtl.mit.edu>> On Behalf Of Chris Cott
Sent: Tuesday, April 15, 2025 3:01 AM
To: labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu>
Subject: [labnetwork] Glow around metals during ebeam evaporation

You don't often get email from chris.cott at nanomelbourne.com<mailto:chris.cott at nanomelbourne.com>. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification>

Hi all,

We have been noticing an intermittent issue in two of our ebeam evaporators.

The symptoms are:

- A blue/green glow around the area the beam contacts the material

- Higher than usual power requirements to evaporate

- Partial deflection of the beam (e.g., a sweep pattern that is usually contained within the crucible starts to contact the edges)

This happens only sometimes and only with certain materials, including Ag and Cu.

Is anyone familiar with this and its cause? Is the glow plasma or Bremsstrahlung from electrons being deflected? Can anyone point us in the right direction towards a solution to the issue?

Thanks in advance!

Chris

-------------------------------------------------------------------------------------------
Chris Cott     BAppSc, BSc, PhD.

Process Engineer,

Melbourne Centre for Nanofabrication

151 Wellington Road, Clayton  3168

Victorian Node of the Australian National Fabrication Facility

Ph:  +61 (3) 9905 1562

W:   http://nanomelbourne.com<https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fnanomelbourne.com%2f&c=E,1,OkpNVSWyFbOG6YjCiRY9KkDPzTg6_wNxvg3OSxRtvIqMYewpDghQrTKF-iBbogHij40arrUo80Sk6sxV37SvkXB9z-eN_mmhDaUPWHwZ692jPsvIftijic2m&typo=1>

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