Aluminum Nitride Dielectric - Thick Film

Is your application in equipment for semiconductor device manufacture? If so you must understand that this is a highly developed and largely proprietary materials technology. Lacking the support of an established manufacturer of equipment or components for semiconductor fabrication your best bet is to study the patent art and contact ceramics manufacturers that specialize in aluminum nitride components for such applications.

Ed Weldon

Hi,

I assume that you are speaking about 150 microinch thickness, that is 3.75µm.

Why do you want to coat aluminum with AlN?

If for insulation or passivation or piezoelectric in semiconductors or similar then there is a wafer - very flat, very smooth - often silicon, quartz, glass, also other (III-V or II-VI).

On this wafer on top an existing structure there will then be a coating of Al to be used as conducting connections.

On top of these it is useful to have the nitride as an insulator.

To get this surface: have a sputtering or another vacuum coating system. As AlN is an insulator if pure you will need a HF system.

New ones are likely to be above 1million$ may reach to 10M$, used ones above 100K$.

We built a small experimental one - pumps, measurement, gas supply, gas analysis will add up to near 60K$ if bought as new components. Chamber design and welding SS to be added.

Coating procedure: sputtering aluminum in 10^-9 to 10^-8 bar Argon will give aluminum, if Nitrogen added or replacing the Argon then AlN is deposited. Sputtering is done with either DC or HF, voltages up to 1KV, current near 1 A/100cm².

Another possibility is that you want to coat massive aluminum parts with a much thicker layer for protection. This is done with iron and steel with slightly elevated temperature and near 10 bar pressure. So I assume that this may be possible with aluminum too.

RHABE

Hi Rhabe,

Thank you for your answer. Actually I'm looking for AIN thickness 150µm on top of aluminum panel, if possible but base on your answer it's not possible to do that.So look like I need to use the AIN panel and coating with copper for conducting connection. My question, is it AIN panel can be sputter or coating with copper? If can what is the inter metallic layer material need to be used before copper? This is to make sure that the strong adhesion between the AIN and copper layer.

Pls. advice what type of sputter need to use for this process, example DC cathode, DC Pulse , RF and etc.

Thanks and Regards,

Suthib

Hi,

if you can live with a few micrometer thickness of Cu or Al on AlN then sputter-coating will be adequate but cost is much higher than thick-film.

If so, then Al is better as "no" problem with adhesion. (Cleanliness is mandatory!)

Any metal can be sputtered with DC mode - cheapest except ion-plating.

Thick-film (typically 10 to 20 and up to 100µm thickness) is widely used as copper on alumina and silver, gold, palladium etc for highly stable and reliable electronic circuits.

This is printed by screen printing and fired under controlled atmosphere.

Controlled atmosphere is "pure nitrogen" but not too pure.

If oxygen is below 10ppm then no good adhesion, same for oxygen above 20ppm.

Water to be included into the oxygen amount.

Adhesion mechanism is by oxidising a thin layer of Cu to CuO adjacent to the alumina.

If this layer is too thin or not existing - no adhesion, if this layer is too thick then brittleness will limit the quality.

I assume - but I am not sure that the situation is similar on AlN as this is without any doubt partially oxidised on the surface.

RHABE