High-power semiconductor applications represent one of the highest growth sectors of any semiconductor technology as many of the key applications are driven by the creation or conservation of energy. These applications include motor control, HBLEDs, solar concentrator cells, RF/microwave circuits used in radar and telecommunications equipment, the huge automotive electronics sector and large array of high power solid state electronic circuitries.
From a packaging perspective, there are a number of common requirements for these high-power applications: they must handle high electrical currents, dissipate large amounts of heat, manage thermal, expansion-induced stresses for high reliability, exhibit very low processing time at low or ambient temperatures, and be achieved at low cost. Cost, in this case, includes assembly as well as materials. ROHS regulations also add new dimensions to these considerations.
For most high-power semiconductor packaging geometries, the predominant heat dissipation path from the device is through the die attach material. Because the die attach layer is the first packaging layer in contact with the die, its thermal characteristics are the most critical. These characteristics include thermal conductivity, and the thermal resistance at interfaces between the die attach, the device, and the package.
Electrical conductivity is also a highly critical property for most high-power semiconductor applications. Electrical resistance between the die and the package results in localized heating. Thus, the energy efficiency of the device is directly influenced by the electrical performance of the die attach layer, which is most critical for power semiconductors where the largest contribution to the stacked series resistance is typically the die attach layer.
The die attach layer is also the mechanical interface between the low thermal-expansion die (silicon 4.2 ppm/°C) and the packaging material. For die bonded to a copper paddle, for example, the copper temperature coefficient of expansion (CTE) is 17 ppm/°C. If CTE stress is large, portions of the die can go into tension and die cracking can result.
These requirement in high power density electronics and semiconductor application can be addressed with Inkron’s Silver Die Attach Adhesive, Electrically Insulating Die Attach Adhesive abd Silver Sintering Paste products.
Printed and 3D electronics
Low Work Function Electrodes
Organic light-emitting diodes (OLEDs) are currently the most promising technology to dominate next generation displays and solid-state lighting devices. The main advantage of using solution-processed organic semiconductors is the capability of producing large-area and flexible light sources that can be produced in a roll-to-roll process at a relatively low cost. The solubility of organic materials conveniently renders them suitable for solution deposition by means of inkjet printing or spray coating. However, although these OLEDs contain solution-processable organic active layers, suitable electrode materials are also required in order to ensure proper device operation. In particular electron-injection layers remain challenged to perform with sufficient work functionality and necessarily low work function metals such as barium and calcium that are capable of evaporation in high vacuum processes.
Inkron is addressing these issues by developing novel low work function, solution processable metal alloy inks for OLED cathodes. Our cathode alloys provide ease of processing without sacrificing performance and device stability.
Solution Printed ITO replacement Layers
The emerging markets for large area and flexible touchscreens, as well as solution printed OLED devices, require transparent conductor materials that combine low material and processing costs with flexibility, high conductivity, and excellent optical performance. Most of the touchscreen and OLED devices today comprise one such transparent conductive material, ITO or Indium Tin Oxide. Unfortunately, ITO is a ceramic material processed using high vacuum deposition at high temperatures, making its production very expensive. These industries are actively pursuing alternative solutions such as CNT, graphene, and nanowires.
Roll-to-roll metal mesh technology is now predicted to be a future main stream alternative to ITO as low resistance can be achieved even on plastics substrates. The widespread adoption of this technology is dependent on making metal lines finer to make them invisible and eliminate optical defects when coupled with displays.
Inkron offers several fine line printable ink solutions to the manufacturers of the metal mesh films or final sensors based on them. Depending of your choice manufacturing we offer metal complex and nano metal particulate inks and selective electroless metallization kits.
3D printers are now rapidly migrating to factories and homes. While the home 3D printing revolution is largely limited to the creation of small plastic objects, industrial 3D printing already produces various metal, alloy and ceramic structures. Also, electrically conductive fine line structures are being printed with dedicated 3D metal ink printing equipment. 3D printing is already shaping how things around us are being manufactured and with other similar processes such as micro Metal-Injection-Moulding (u-MIM) real device customization, build to order practices taken in use and technology efficiency to materialize.
Inkron is in the process of commercializing various viscosity and surfactant comprising metal nanoparticle inks to address the demand for 3D metallization, and nano powder to enable the most challenging and sophisticated 3D MIM structures.