Christopher James Kapusta

Advanced 3-D stacked technology

Array sensors (e.g. focal plane array detectors) have densely aggregated cells to capture low energy levels that are converted into electrical signals. In hybrid assemblies, where focal plane arrays are bump-bonded to readout ICs, pixel density is being continually increased as processing and assembly technologies improve. Denser arrays, combined with extremely high frame rates (e.g. >106 frames/sec) create a formidable explosion in signal content. One approach to overcoming this issue is to move the signal processing closer to the array, minimizing the number of interconnects and the interconnect length the raw pixel signal outputs must travel prior to digitization, providing opportunity to buffer bursts (<64 frames) of high-rate collection sessions. One innovative approach to achieving this is to use 3D stacking of the pre-processing electronics for each pixel row directly behind the sensor array. This paper describes the development of a high density, 3D stacking technology that is being applied to an 8000-pixel array sensor cube that can eventually be scaled to mega-pixel densities through tiling.

Development of a multiframe optical imaging detector for proton radiography at LANL

In this paper we give a brief report on the development of simple direct- and indirect-detection imagers for proton radiography experiments. We outline a conceptual design for a novel, multi-frame 5 mega frames per second (Mfs) hybrid imager. The high-density interconnect is identified as a critical enabling technology. We present a description of a 3D electronics packaging cube, which was completed in a recent feasibility study.

Reliability of POL-kw power modules

Wide band gap (WBG) semiconductor devices have demonstrated superior electrical and thermal performance, compared to their silicon-based counterparts. However, innovative power module packaging design and materials suitable to WBG devices are required. In this paper, the development of a new high power density module using the Power Overlay (POL) packaging platform is presented. The wirebond-less packaging platform has shown significantly reduced electrical parasitics, while providing a thin profile to allow double-side cooling and the integration of gate drive circuits. Thermal cycling and high temperature storage tests were conducted on specimens fabricated and assembled by production equipment. The results presented here were used to establish design guidelines for reliable operation of POL-based power modules.

Electronic packaging of SiC MOSFET-based devices for reliable high temperature operation

Silicon carbide (SiC) devices allow electronics to operate at high junction temperatures (>200°C) and high voltages (>10 kV). In addition, they provide faster switching and lower power losses than their silicon-based counterparts. Recently, MOSFET (metal-oxide semiconductor field effect transistor) devices were demonstrated to work up to 500°C. Robust packaging solutions are needed to take advantage of the extreme temperature capability in the areas of propulsion, power generation, and oil/natural gas exploration. This paper reviews the current packaging challenges for 400-500°C operation temperature, and presents a hermetic package solution for reliable operation.

Novel Packaging Method for Miniature High Temperature Piezoelectric Actuators

There is a need for miniature actuators that operate at high temperature, high frequency and lend themselves to integration with other small devices such as relays, valves and micro electromechanical systems (MEMS). Actuators based on piezoelectric materials have the potential to develop high forces at high frequency, but operation at elevated temperature may be problematic and obtaining useful stroke as the actuator is scaled down in size is a significant challenge. This paper presents the design and fabrication steps for a novel piezoelectric actuator that addresses these challenges and is capable of operating at temperatures in excess of 200°C with a stroke greater than 10μm and a length of less than 25mm. Several packaging adhesives and two piezoelectric materials were evaluated for the miniature actuator design. Results indicate that although this first generation device did not meet the stroke requirement of 10μm, the high temperature package design will enable new capabilities for next generation devices.Copyright

Integration of 50-GHz traveling-wave amplifier and polymer Mach-Zehnder device using flexible substrate technology

We present the results for a 50GHz drive amplifier for use with a Mach-Zehnder modulator. The MMIC device is packaged using a flexible substrate technology to obtain compact size and broadband performance. The packaged device exhibits well-matched transmission lines on the input and output, and large gain and bandwidth. The MMIC performance is directly related to performance of the drain bias circuit.