New improvements in thermal management: Thick print copper thick film as a replacement for Direct Bond Copper

Direct Bond Copper (DBC) is a widely proven process used in areas such as high power handling applications where thermal management is a priority. The benefits of DBC include excellent thermal conductivity and high current carrying capability, as well as good mechanical strength and adhesion. However, there are several drawbacks to traditional DBC technology. These include thermal cycling performance, minimum copper foil thickness, and pattern limitations due to the fact that the foil must be etched, which is a relatively expensive subtractive process. With new applications such as Concentrated Photovoltaics (CPV), High Brightness LED Packaging, and Insulated Gate Bipolar Transistors (IGBT) a new material solution is needed for high power electronics. Thick film copper can offer improvements over DBC by improving thermal cycling performance, as well as filling a gap where a thickness of less than 150μm is difficult to achieve with the standard processing procedures of DBC. Tighter resolutions are easier to accomplish with the thick film Cu approach enabling the use of a thinner layer of copper for more versatility, and improving line resolution to allow increased design flexibility. This paper examines a direct comparison of DBC to Thick Print Cu on the substrates BeO and alumina. Not only are there the advantages in thickness, lifetime testing, and pattern guidelines, there is the distinct cost-savings advantage of applying an additive process for thick print Cu. These results are compared and show improvements that have been made in optimizing the performance of Thick Print Cu.