Chris Kapusta

Design and Development of a Package Using LCP for RF/Microwave MEMS Switches

We present the development of an ultrahigh moisture-resistant enclosure for RF microelectromechanical system (MEMS) switches using liquid-crystal polymer (LCP). A cavity formed in LCP has been laminated, at low temperature, onto a silicon MEMS switch to create a package. The LCP-cap package has an insertion loss of less than 0.2 dB at X-band. E595 outgas tests demonstrate that the LCP material is suitable for constructing reliable packages without interfering with the operation of the MEMS switch. The package also passes Method 1014, MIL-STD-883 gross leak, and fine leak hermeticity tests

Multilayer Organic Multichip Module Implementing Hybrid Microelectromechanical Systems

We present the design and development of an organic package that is compatible with fully released RF microelectromechanical systems (MEMS). The multilayer organic package consists of a liquid-crystal polymer film to provide near hermetic cavities for MEMS. The stack is further built up using organic thin-film polyimide. To demonstrate the organic package, we have designed and implemented a 2-bit true-time delay X-band phase shifter using commercially available microelectromechanical switches. The packaged phase shifter has a measured insertion loss of 2.45 plusmn 0.12 dB/bit at 10 GHz. The worst case phase variation of the phase shifter at 10 GHz is measured to less than 5deg. We have also conducted temperature cycling (-65degC to 150degC) and 85/85 to qualify the packaging structures.

Development of Multilayer Organic Modules for Hermetic Packaging of RF MEMS Circuits

We present the design and development of a multilayer organic module that can integrate microelectromechanical systems (MEMS) into a system-in-a-package (SiP). A cavity formed in liquid crystal polymer (LCP) has been laminated, at low temperature, onto a MEMS silicon switch to create a hermetically sealed package. Multilayer organic dielectrics can be integrated on top of LCP films to form a 3D SiP module. The entire SiP hermetically sealed package has a total insertion loss of ~0.1 dB at X-band. The package also passes Method 1014, MIL-STD-883 gross leak and fine leak hermeticity tests. We have demonstrated a 2-bit RF MEMS TTD (true-time delay) switched line phase shifter in this multilayer organic module. The phase shifter achieves an average insertion loss of 1.8 dB/bit, with less than 3deg phase shift variation

Eddy current sensor for in-situ monitoring of swelling of Li-ion prismatic cells

In-situ monitoring an on-board rechargeable battery in hybrid cars can be used to ensure a long operating life of the battery and safe operation of the vehicle. Intercalations of ions in the electrode material during charge and discharge of a Lithium Ion battery cause periodic stress and strain of the electrode materials that can ultimately lead to fatigue resulting in capacity loss and potential battery failure. Currently this process is not monitored directly on the cells. This work is focused on development technologies that would quantify battery swelling and provide in-situ monitoring for onboard vehicle applications. Several rounds of tests have been performed to spatially characterize cell expansion of a 5 Ah cell with a nickel/manganese/cobalt-oxide cathode (Sanyo, Japan) used by Ford in their Fusion HEV battery pack. A collaborative team of researchers from GE and the University of Michigan has characterized the free expansion of these cells to be in the range of 100×125 microns (1% of total cell...

Novel thin temperature and expansion sensors for li-ion battery monitoring

This paper introduces a combined temperature and displacement sensor for new measurements of physical parameters which can inform multi-physics based models of Li-ion batteries. These flexible sensors can be placed directly on the cell to measure intercalation effects which can improve battery state estimation. The sensors were characterized on individual Panasonic cells and subsequently, packaged into a 76 cell Ford Focus hybrid electric vehicle (HEV) pack, which was cycled for 5000 equivalent miles. Results showed improvement in temperature estimation capability with the combination of sensor and model. However, the low expansion of the hard cased cells limited utility of the eddy current sensors.

Harsh-Environment Packaging for Downhole Gas and Oil Exploration

This research into new packaging materials and methods for elevated temperatures and harsh environment electronics focused on gaining a basic understanding of current state-of-the-art in electronics packaging used in industry today, formulating the thermal-mechanical models of the material interactions and developing test structures to confirm these models. Discussions were initiated with the major General Electric (GE) businesses that currently sell into markets requiring high temperature electronics and packaging. They related the major modes of failure they encounter routinely and the hurdles needed to be overcome in order to improve the temperature specifications of these products. We consulted with our GE business partners about the reliability specifications and investigated specifications and guidelines that from IPC and the SAE body that is currently developing guidelines for electronics package reliability. Following this, a risk analysis was conducted for the program to identify the critical risks which need to be mitigated in order to demonstrate a flex-based packaging approach under these conditions. This process identified metal/polyimide adhesion, via reliability for flex substrates and high temperature interconnect as important technical areas for reliability improvement.

Adhesive Tiecoat/Polyimide Interactions in High Temperature Flex Packaging

The high temperature reliability of flex-based Cu/tiecoat/polyimide structures was evaluated through finite element simulation and experimental approach. This study is part of an effort to characterize and optimize polyimide flex as a substrate material for electronics packages rated to greater than 204°C. The peel strength of several common adhesion metals (Ti, Cr, Ni, Cu) on Kapton E was quantified at room temperature and after high temperature storage in inert and highly oxidizing environments. These results were used in tandem with thermal-mechanical simulations to characterize the behavior of several tiecoat materials. Experimental results showed diminished peel strengths of both the Ti and Cr after a 100-hour 250°C heat treatment in air. However when annealed in an inert N2 environment at 250°C for 100 hours, Cr, Ni, and Ti retained their as-sputtered peel strength. Ni and Cu exhibited lower mechanical stresses in the simulation; however, their relatively low reactivity limits their adhesion strength at the interface in oxidizing environments. To further understand the origin of the thermal-mechanical stress, the effect of mismatched CTE was compared to mismatched elastic modulus. Both properties were found to contribute to stress generation; however elastic modulus mismatches had a much greater influence on the overall magnitude of the stress. Through experimentation and FEA analysis this study aims to develop a flexed-based high temperature packaging solution and to shed light onto high temperature tiecoat/polyimide interactions.Copyright

Development of a Hermetically Sealed Enclosure for MEMS in Chip-on-Flex Modules Using Liquid Crystalline Polymer (LCP)

We present the development of a hermetic shield packaging enclosure for RF microelectromechanical system switches (MEMS) using Liquid Crystal Polymer (LCP). A cavity formed in LCP has been laminated, at low temperature, onto a Si MEMS switch to create a hermetically sealed package. The hermetically sealed enclosure is a stack-up layer of the multi-layer organic chip-on-flex system-on-a-package (SOP). The entire SOP hermetically sealed package has a total insertion loss of ∼0.5 dB at X-band. E595 outgas tests demonstrate that the LCP package is reliable and hermetically protects the MEMS switch.Copyright

50-GHz drive amplifier for integration with polymer Mach-Zehnder device

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.