Spectrum Control specializes in the screen printing of multi-layer thick-film hybrid interconnect on ceramic substrates up to a size of 203 x 152 mm. Material systems include gold for wire bonding and blends of silver and gold with platinum and palladium for solder based assemblies.
Conventional screen printing is supplemented by a photo-defined process to achieve high-density, high-precision conductors (25um width). Diffusion Patterning is also employed to provide small diameter, high density vias in dielectric layers.
Thick film interconnect incorporates laser adjusted resistors printed directly onto the ceramic substrate saving space and allowing the designer a completely free choice in resistor value and extremely close tolerance matching. Thick film resistors can be designed and printed to any value by combining resistor aspect ratio (length:width) with the appropriate paste value. Resistor pastes are available in decade series typically from 10ohm/square to 1Mohm/square. Adjacent nominal values may be blended to achieve the desired 'jar value' for the layout design. The use of bare die and selected passive components bonded directly to ceramic substrates promotes reliability and improves thermal management in harsh environments.
Components are added to the completed thick film hybrid substrate using standard surface mount soldering (RoHS compliant or SnPb) or solder-less conductive epoxy attach methods. These two assembly methods can be combined in a mixed technology design which helps to maximise the level of integration in a highly cost effective solution.
Conventional thick-film screen printing is the industry standard technology. For higher density packaging and critical signal routine associated with high-frequency modules, the standard printed conductor line width and definition are inadequate. Photo-defined technology can be seen as an extension of standard thick-film technology, offering lines and spacings down to 25 µm. With its high level edge definition and high conductivity, the technology is well suited to RF and microwave applications.
We have established production capability with the two leading photo processing solutions: Fodel technology, registered by DuPont, and KQ technology, registered by Heraeus. These processes have been perfected on LTCC and alumina tiles of size 100 mm x 100 mm. They provide a low-cost, high-definition interconnect with resolution and RF electrical performance approaching that of thin film. Applications range from cellphone RF amplifiers to microwave modules.
We have a dedicated Class 100 clean room for medium-volume production of high-density interconnect.