Fig. 1. Multi-layer toroidal inductors created in LTCC, [1], [2].

In advanced packaging, Professor Chappell's research group is attempting to expand the role of vertical integration in high frequency circuits.
He has garnered industrial attention through the integration of ceramic multilayer circuits with less traditional integrated circuit techniques for the development of commercialized vertically integrated circuits. Through earlier work in two DARPA-sponsored projects which focused on vertical integration of packaging for high frequency communications (satellite and terrestrial), he was able to establish an advanced packaging laboratory garnering large equipment donations from industry to create a Low Temperature Cofired Ceramic (LTCC)/ organic board packaging laboratory. Since then, this laboratory has been where much of the design and fabrication for our research group occurs.

Fig. 2. First lumped-elements-based absorptive bandstop filter on LTCC [3].

The advanced packaging laboratory has a wide range of tools available for use. This includes machines for LTCC assembly such as screen printers, a precision punch, inspection stations and several ovens which form a fully capable LTCC product development area. The lab also contains a polymer deposition system (Parylene CVD) that provides conformal coatings of Parylene film, and a stereolithography machine which is used to form arbitrary 3-dimensional shapes out of polymer. There is also a milling machine that can be used to fabricate large scale planar circuits as well as patch antennas and similar devices. There are also several computers in the lab that are used for simulations.

Fig. 3.  Flexible electronics on multilayer Parylene interposer [4], [5].

The work in this laboratory is supplementary to the work done in the Birck Nanotechnology Center that allows for full system level solutions at a packaging level supporting the more traditional wafer-based work found in most solid state/MEMS laboratories. We also have collaboration with local design and assembly companies and utilize it when industry experience in product design and prototyping is required. This lab has provided the group with a unique area in high frequency circuits and will be the basis for our research for years to come in the high frequency circuit arena.

Currently Involved Students

Recent Publications

[1] E. E. Hoppenjans, W. J. Chappell “High Value Passive Component Integration in LTCC Technology” IEEE MTT-S International Microwave Symposium Digest (IMS2007), June 2007, pp. 1913-1916.

[2] E. E. Hoppenjans, W. J. Chappell, "The Use of High Q Toroid Inductors for LTCC Integrated Tunable VHF Filters," IEEE MTT-S International Microwave Symposium Digest, June 2009, pp. 905-908.

[3] J. Lee, T.-C. Lee, and W. J. Chappell, "Lumped Element Realization of Absorptive Bandstop Filter with Anomalously High Spectral Isolation," IEEE Transactions on Microwave Theory and Techniques, accepted for publication.

[4] J. Maeng, B. Kim, D. Ha, and W. J. Chappell, “Thin-Film Multilayer Parylene Interposer for High-Density 3D Packaging with Embedded Capacitors,” IEEE MTT-S International Microwave Symposium Digest (IMS2011), June 2011, pp. 1-4.

[5] J. Maeng, B. Kim, D. Ha, and W. J. Chappell, “Parylene Interposer as Thin Flexible 3D Packaging Enabler for Wireless Applications, ” IEEE Transactions on Microwave Theory and Techniques, vol. 59, no. 12, pp. 3410-3418, December 2011.

The laboratory’s LTCC fabrication capabilities include:

• product/network design
• translation of design files
• screen and stencil file generation
• material preconditioning
• material punching (via hole generation)
• via-fill and conductive trace print

• vacuum seal and isostatic lamination
• complex cavity and shape creation
• organic burnout and sintering
• product singulation
• inspection and measurement
• package/braze/component attach

Click here for a downloadable overview of our Advanced Packaging capabilities.