I got tired of etching down materials with chemicals for diaphrams so I decided to DIY a sputtering machine.
After a couple afternoons of googling I've determined that a dual cathode unbalanced planar magnetron system may be what I need since they are used on larger substrates. I've thought about a quad magnetron but one step at a time.
I'll be custom fabricating the cathodes via a milling service and constructing a robust vacuum chamber but before I do that I'm going build a crude prototype first, using external magnets and applying the target materials to holes on the outside of a custom diy acrylic vacuum chamber.
The vacuum will seal the target material to the chamber during use.
I'm going to use some used ion pumps from ebay to provide the vacuum.
The dimensions are a bit skewed in that picture but you get the idea.
I think the need to get watercooling on the cathodes may be required so I might need to mill some out before attempting this.
One big question I have hanging over my head is what the dimensions of the target material should be.
I haven't been able to find much literature on this, only that the target should be larger than the substrate area.
Since my substrate is rectangular in shape, naturally I am considering making the target material a rectangular block, but rectangular cathodes are only used in conveyer belt type sputtering systems and there are vague mutterings that circular cathodes may provide a more uniform deposition on to the substrate, but he information I've found is unclear.
There's also the fact that most substrates used in sputtering are circular in nature and none of the literature may apply to rectangular substrates.
I'm currently planning on making the target material twice as wide and long as the substrate as it intuitively seems like it would be the most efficient and linear way to deposit the material.
I'm wondering if anyone here is knowledgeable enough about this subject to tell me if this is a good/bad idea and why.
My other big question is, why does the magnetic structire always have a N/S/N configuration on the cathode? Why not a longer N/S configuration? Or why not a N/S/N/S/N/S configuration?
The material sputtters off at the field between the N and S poles, so it makes sense to have either one large field or many small ones so avoid the typical 'racetrack' utilization pattern on the material.
Is it more important to keep the fields close to the target material or can the field bend outward a bit?
Not a whole lot of literature I can find on this stuff.
I would love to hear any advice on construction and or any other details.
I'm going to need all the help I can get to do this right without making costly mistakes.
Much appreciated if anyone can help.
After a couple afternoons of googling I've determined that a dual cathode unbalanced planar magnetron system may be what I need since they are used on larger substrates. I've thought about a quad magnetron but one step at a time.
I'll be custom fabricating the cathodes via a milling service and constructing a robust vacuum chamber but before I do that I'm going build a crude prototype first, using external magnets and applying the target materials to holes on the outside of a custom diy acrylic vacuum chamber.
The vacuum will seal the target material to the chamber during use.
I'm going to use some used ion pumps from ebay to provide the vacuum.
The dimensions are a bit skewed in that picture but you get the idea.
I think the need to get watercooling on the cathodes may be required so I might need to mill some out before attempting this.
One big question I have hanging over my head is what the dimensions of the target material should be.
I haven't been able to find much literature on this, only that the target should be larger than the substrate area.
Since my substrate is rectangular in shape, naturally I am considering making the target material a rectangular block, but rectangular cathodes are only used in conveyer belt type sputtering systems and there are vague mutterings that circular cathodes may provide a more uniform deposition on to the substrate, but he information I've found is unclear.
There's also the fact that most substrates used in sputtering are circular in nature and none of the literature may apply to rectangular substrates.
I'm currently planning on making the target material twice as wide and long as the substrate as it intuitively seems like it would be the most efficient and linear way to deposit the material.
I'm wondering if anyone here is knowledgeable enough about this subject to tell me if this is a good/bad idea and why.
My other big question is, why does the magnetic structire always have a N/S/N configuration on the cathode? Why not a longer N/S configuration? Or why not a N/S/N/S/N/S configuration?
The material sputtters off at the field between the N and S poles, so it makes sense to have either one large field or many small ones so avoid the typical 'racetrack' utilization pattern on the material.
Is it more important to keep the fields close to the target material or can the field bend outward a bit?
Not a whole lot of literature I can find on this stuff.
I would love to hear any advice on construction and or any other details.
I'm going to need all the help I can get to do this right without making costly mistakes.
Much appreciated if anyone can help.
I worked in the optical disc industry for a while and have some experience with the sputtering process. CDs were sputtered with aluminum and dual layer DVDs had one aluminum layer and the other was silver. The targets were about 6" dia. and 1" thick. The target was located at the top of the chamber, followed by a metallic mask and then the disc (substrate) below. Distance from the target to the substrate was about 2". Discs were shuttled in/out of the chamber by a rotary platter every few seconds. In addition to the intense vacuum, Argon gas was also used in the process, if memory serves me correctly. I know this doesn't give you a lot to go on, but I think the detailed info should be out there, perhaps if you search by specific application rather than just sputtering in general. Our equipment was made by Steag Hamatech, of Germany. The sputtering stations were modular sections, on wheels, and could be pulled away from the rest of the DVD line for service. Maybe there are still some used ones around.
Yeah I've been reading as many publications as I can. I have a pretty decent understanding of how the process works. It's the details like cathode size and magnetic field construction that I'm having a hard time finding information on.
Plus there's always the unknown unknowns.
For the moment the most important thing I need to do is make the cathode I think. Starting with a single cathode.
I think the watercooling is going to be required as to not melt the target unless I get a really thick target.
I just need to find a source of information for the cathode and shield material. I saw one diagram say that the cathode is made of stainless steel but I'm not sure about the shield material.
Stainless steel is seemingly quite expensive to mill so I need to see if I can't use a less expensive material.
Plus there's always the unknown unknowns.
For the moment the most important thing I need to do is make the cathode I think. Starting with a single cathode.
I think the watercooling is going to be required as to not melt the target unless I get a really thick target.
I just need to find a source of information for the cathode and shield material. I saw one diagram say that the cathode is made of stainless steel but I'm not sure about the shield material.
Stainless steel is seemingly quite expensive to mill so I need to see if I can't use a less expensive material.
Satis Vacuum, Switzerland also made such systems.
Find a closed disk plant, plenty around, and use that machine.
See machinery auction sites.
Find a closed disk plant, plenty around, and use that machine.
See machinery auction sites.
So it seems that aluminum is suitable for high vacuum as a replacement to stainless steel but stainless steel is twice as stiff. So some calculations will need to be done in order to determine the thicknesses required in order to determine which is cleaper.
It turns out that unbalanced cathode configurations heat up the substrate which isn't going to work for mylar deposition so I'll be using a balanced, single cathode system for now.
I'll need to toy with magnetic configurations and therefore I'll be using fat blocks of aluminum and using the vacuum to seal them against the chamber wall from the outside until I find a satisfactory magnetic solution.
It turns out that unbalanced cathode configurations heat up the substrate which isn't going to work for mylar deposition so I'll be using a balanced, single cathode system for now.
I'll need to toy with magnetic configurations and therefore I'll be using fat blocks of aluminum and using the vacuum to seal them against the chamber wall from the outside until I find a satisfactory magnetic solution.
Pre-build machines won't work because the substrate (the diaphragm) is going to be huge.
Check out the American Vacuum Society (it sucks) YouTube page:
https://www.youtube.com/channel/UCZxIp5pGM42Sp1nqzs-p3Vg
https://www.youtube.com/channel/UCZxIp5pGM42Sp1nqzs-p3Vg
Your substrate will be bigger than a CD?
Those were progressive vacuum systems with metal deposition, aluminum I think.
Those were progressive vacuum systems with metal deposition, aluminum I think.