Electronics assemblies are formed in a wide variety of configurations for a wide variety of applications. Often, however, they are comprised of a plurality of individual electronic components mounted on a circuit board or other substrate. The individual electronic components typically communicate electronically with each other through the substrate to form a useful electronic assembly. Although the individual electronic components themselves may come in a wide variety of embodiments, one particular type is commonly referred to as a power device. Power devices are electronic components that generate heat during operation. Commonly, the thermal energy generated by these power devices must be dissipated in order for the electronic assembly to function properly. Some power devices must be kept within a predetermined thermal range in order to reliably perform their function. Others, while able to withstand larger temperature ranges, may damage the substrate or neighboring electronic components if the thermal energy is not properly dissipated.
Numerous approaches have been developed in order to dissipate heat from these power devices. Various combinations of convection and radiation transfer have been utilized to transfer the thermal energy from the power devices. One well-known and successful approach has been through the use of a heatsink device. Heatsink elements provide a thermal well, also known as a coldplate, to absorb the heat generated by power devices. The coldplate often takes the form of large blocks of metal, or other thermal conductive material, with the capability of absorbing the thermal energy from the power devices and dissipating it over a larger surface area. The specific configuration of such coldplates is virtually limitless, although common embodiments such as metal blocks, cases, and heat rail brackets are well known. Although the coldplate may be modified into a variety of forms, thermal communication between the coldplate and the power devices often requires careful design consideration.
One approach to providing communication between the heatsink element and the power devices has been weld a conductive buffer, such as copper, to a backplate (often aluminum). The conductive buffer provides an effective surface to thermally mount the power device, while the backplate creates a resilient structure capable of mounting to the coldplate. Heat generated by the power device is transferred through the conductive buffer, through the weld nugget, through the backplate and into the coldplate. Although this design has been widely utilized, it does present several undesirable design characteristics. Materials, such as copper, that are high in thermal conductivity are desirable for direct communication with the power device. This ensures that heat is quickly and easily pulled from the power device. These high conductivity materials, however, often lack the structural resilience necessary to form a mountable backplate. The backplate, in turn, while structurally resilient, is often of a material such as aluminum which may not share the high thermal conductivity desired of the buffer.
The resultant present method, therefore, leaves significant room for improvement. The effectiveness of the high thermal conductivity of the buffer can be reduced by the impact of the backplate. This can be further impacted by the weld nugget often used to attach the buffer to the backplate. The weld nugget is commonly smaller than the conductive buffer plate, and therefore the cross-sectional area of thermal communication between the buffer plate and the backplate is reduced. This creates a negative impact on the thermal conductivity of the heat-sink stack as a whole. It would be preferable to minimize any negative impact on the thermal conductivity, or even improve conductivity, while retaining the structural resilience associated with present designs. It would also be desirable to create possible reductions in manufacturing time and cost through the elimination of the weld nugget utilized in present designs. This would also realize an improvement over the thermal conductivity reduction associated with present weld nugget usage.