Juergen Wilde

Fabrication and test of a hermetic miniature implant package with 360 electrical feedthroughs

A fabrication technology for small hermetic implant packages with large numbers of electrical feedthroughs is presented. First prototypes were fabricated on a ceramic substrate of 25·25 mm area, having a metal cup of 5 mm height soldered to it. These prototypes provide 360 feedthroughs. The electrical properties of the feedthroughs are characterized and the leakage rate of the packages is determined using helium fine leak tests. The amount of water sealed inside the packages is investigated. Based on maximum allowable water vapour concentrations inside hermetic packages reported in literature and applying a commonly accepted mathematical model, we predicted a minimum lifetime to water-induced failure of a few hundred years.

A device for vacuum drying, inert gas backfilling and solder sealing of hermetic implant packages

Modern implanted devices utilize microelectronics that have to be protected from the body fluids in order to maintain their functionality over decades. Moisture protection of implants is addressed by enclosing the electronic circuits into gas-tight packages. In this paper we describe a device that allows custom-built hermetic implant packages to be vacuum-dried (removing residual moisture from inside the package), backfilled with an inert gas at adjustable pressure and hermetically sealed employing a solder seal. A typical operation procedure of the device is presented.

Dynamic Stress Measurements of Electronic Devices during Active Operation

In this work an investigation on dynamic stress development during switching operation of power electronic devices is presented. Two measurement techniques were used to analyze the behavior of devices which were mounted withelectrically conductive adhesives. A self-heated silicon test chip with CrNi-thin film strain gauge structures was developed. The heating function enables simulation of thermal operating conditions and comparison of passive and active heating. Digital Image Correlation was used as a contactless technique for reference measurements in active operation. The out-ofplane deformation of assembled IBGTs on Al2O3-DCB substrates was measured. Both methods were used for timeresolved measurements of the stress development.