A printed circuit board composed of several layers
A multilayer is made up of multiple layers that are laminated together to form a printed circuit board. The outer layersof a multilayer are usually single-sided PCBs, whereas the inner layers are double-sided materials. Insulating layers, so-called prepregs,are inserted between the conductive layers. Up to four layers can be through-hole plated in a chemical-free process. For electrical connection of up to eight layers through-hole electroplating is recommended.
Three steps to a multilayer
An LPKF ProtoMat circuit board plotter or an LPKF ProtoLaser structures the traces on the base material using the layout data. Supported by automatic tool change and a camera for recording of fiducials, the system accomplishes this layer by layer – nearly automatically.
The structured layers are precisely stacked. Between the layers, “prepregs” insulate the traces on the different layers. During lamination the prepregs connect the layers. The LPKF MultiPress S4 hydraulic press performs the task of lamination– with perfect results, even for HF multilayers, thanks to preset process profiles.
The electrical connections between the individual layers form the final conductor structure. The LPKF ProtoMat circuit board plotter drills the through-holes. LPKF ProConduct is used for electrical connection – in a chemical-free process using a special conductive paste. For more than four layers, through-hole electroplating is recommended.
Video Inhouse PCB Multilayer Process
Systems for Multilayer Production
The LPKF ProtoMat S104 is the system of the ProtoMat S family with automatic tool change, vacuum table and camera for optical registration of the register marks. Automatic milling width adjustment ensures precise PCB structures with identical milling channels.
With the LPKF ProtoLaser S4, it only takes a few minutes from the layout to the structured circuit board - exact geometries on many substrates. The ProtoLaser S4 can also reliably process copper surfaces with inhomogeneities up to 6 μm and is ideally suited for the production of multilayers.
The stand-alone system with intuitive software, predefined process settings for common materials and a large touchscreen makes laminating very easy. The vacuum function and precise temperature and pressure profiles are the key to success.
The electrical connections between the individual layers are made by LPKF ProConduct, a chemical-free system specially developed for laboratory use. If there are more than four layers, galvanic through-hole plating is recommended.
With multilayers, the connection of layers with vias is of particular importance. The classical galvanic process is obligatory for six layers or more. The LPKF Contac S4 table system is easy and safe to operate without chemical knowledge.