Aaron Reinholz

A Printed Rampart-Line Antenna with a Dielectric Superstrate for UHF RFID Applications

A printed Rampart line antenna with a dielectric superstrate for passive radio frequency identification (RFID) tags is presented. A design process is outlined to determine the number of elements used in the rampart line antenna to achieve the required gain for the desired read range. An inductive loop is then added to the port to match the antenna with the passive tag circuitry. It is shown that a passive tag with a printed Rampart line antenna and a dielectric superstrate can achieve comparable read ranges to commercially available passive RFID tags.

A unique application of decapsulation combining laser and plasma

Often the greatest cost for developing a new package or system is the acquisition of bare chips. To meet this challenge, a unique technique involving laser and plasma has been developed for extracting dice or chips for reuse and repackaging. Epoxy molded integrated circuit (IC) packages are decapsulated using a combination of a neodymium-doped yttrium aluminum garnet (YAG) laser and reactive ion etch (RIE) plasma etcher. Using the parameters mentioned in this paper, a yield of over 70% of functional packages was achieved at the end of decapsulation.

Effect of concurrent Mg/Nb-doping on dielectric properties of Ba0.45Sr0.55TiO3 thin films

Composition, microstructure, and dielectric properties of undoped and Ba(Mg1/3Nb2/3)O3 (BMN) doped Ba0.45Sr0.55TiO3 (BST) thin films deposited via rf. magnetron sputtering on platinized alumina substrates have been investigated. The analysis of microstructure has shown that despite the sizable effect of doping on the residual stress, the latter is partially compensated by the thermal expansion coefficient mismatch, and its influence on the BST film crystal structure is insignificant. It was revealed that BMN doped film demonstrated an average (over 2000 devices) of 52.5% tunability at 640 kV/cm, which is ∼8% lower than the value for the undoped film. This drop is associated with the presence of Mg ions in BMN; however, the effect of Mg doping is partially compensated by that of Nb ions. The decrease in grain size upon doping may also contribute to the tunability drop. Doping with BMN allows achievement of a compensation concentration yielding no free carriers and resulting in significant leakage current r...

On the effect of mutual coupling on LF and UHF tags implemented in dual frequency RFID applications

The performance of many different dual frequency tag configurations were tested in a commercially available dual frequency RFID system. It has been shown that the interaction between the LF and UHF tags can have a significant impact (i.e., 91.84% reduction in read range) on the performance of each individual tag. But, in all cases it has been shown that by proper placement of the LF and UHF RFID tags the performance of each individual tag in the dual-frequency tag can be preserved. In the Rampart line case to preserve the performance of an individual tag a larger footprint was not needed.

Tape Peel Testing as a Simple Method to Evaluate Interfacial Adhesion of Sputtered Thin Layers of Various Metals

The quality and reliability of electronic systems depend on the integrity of interfacial adhesion. Adhesion is critical at all electronics assembly levels. Material layers on a chip, package and system need to have excellent adhesion to each other. Thin films are an integral part of chip devices and also are necessary at other levels of electronic systems. The quality and reliability of their interfacial adhesion defines the quality and reliability of the finished product. To assure interfacial adhesion integrity, numerous measurement techniques are employed. Most of these measurement techniques require the use of sophisticated and expensive equipment. Of the simpler techniques, one is tape peel testing which usually is used as a go no-go screening test. This paper outlines its application as a valid quantifiable evaluation tool. In this narrative, testing setup and measurement procedure is outlined for tape peel testing. The procedure was used successfully to evaluate and choose pretreatments to enhance interfacial adhesion of sputtered thin layers of various metals. It is shown that the procedure provided results which could be validated through subsequent thick film peel testing. Thin films are used industry-wide in applications other than electronic systems, therefore, this study is applicable industry-wide providing a quantifiable method to measure thin film adhesion.Copyright