Stainless-steel multilayer PCB

For perfect shielding of coils in a printed circuit we included a 0,3mm stainless steel plate into a 9-layer-hybrid-multilayer. Furthermore, the final thickness and layer distance of this stack-up had to be extremely accurate, because the later stainless steel housing would be interacting from the other side, putting the coils into a shielding "sandwich".

Lamination of special materials, so called hybrids, require ever larger levels of innovation. Apart from conventional PCB materials such as copper, aluminium, polyimide, ceramics and PTFE - to only mention a few -this stainless-steel multilayer required unprecedented techniques and process developments. Compared to most other PCB materials, stainless steel is extremely difficult to drill and abrade. If processed incorrectly, this will cause delamination problems later. 

Using different combinations of mechanical and chemical abrasion the weak adhesion capabilities of the stainless steel layer could be eliminated and be laminated using special prepregs. The result is a printed circuit board that can be processed in a reflow-oven and sustains normal surrounding climates reliably. An additional challenge in this PCB was the exact layer distance inside the stack-up. The complete multilayer has be manufactured with a height deviation of below 3% while standard deviations in other PCBs may range at ±10%.

If you have special requirements for uncommon materials in PCB multilayers that exceed copper, aluminium, stainless steel or ceramics, please contact us. There is a wide range of materials that has never been implemented into a multilayer printed circuit board. Challenge us!