sputter coater plasma colour

[Ben Buse]

Hi,

On a gold sputter coater - does anyone know why the plasma colour changes from blue to pink during sputtering? Is this normal?

Thanks

Ben

[Probeman]

On a gold sputter coater - does anyone know why the plasma colour changes from blue to pink during sputtering? Is this normal?

Hi Ben,
I found this wiki page:

https://en.wikipedia.org/wiki/Gas-discharge_lamp

On nitrogen they say "Similar to argon but duller, more pink; at high peak currents bright blue-white", so I'm guessing you're seeing nitrogen from an air leak?
john

[Les Moore]

Could it be that you have sputtered through the gold coating on the target and started on the copper.  Alternatively, as mentioned above, you don't have an Ar supply but an air supply.

[Ben Buse]

No it's not going through the gold target.

So I guess it purges with argon at the beginning before sputtering, then all the argon gets used up and it changes color? Would that do it?

Thanks

Ben

[jon_wade]

no, you most likely have a leak - ours does this (but it is 45 years old....).  When its purging, the vac pump is running - when its coating, it seals off the vac pump and does its thang.  But its leakier than a sieve, hence as coating 'progresses' it gets more pink. As our timer is broken, I judge the thickness by the plasma colour.......  Yes, I'm trying to buy something more.....modern.

[Probeman]

no, you most likely have a leak - ours does this (but it is 45 years old....).  When its purging, the vac pump is running - when its coating, it seals off the vac pump and does its thang.  But its leakier than a sieve, hence as coating 'progresses' it gets more pink. As our timer is broken, I judge the thickness by the plasma colour.......  Yes, I'm trying to buy something more.....modern.

I agree with Jon. I think you have an air leak.