We analyzed the high frequency dielectric relaxation mechanism in high-k composite materials using film substrates made of low loss organic resin filled with ferroelectric ceramics and with single wall carbon nanotubes (SWNT). We performed broadband permittivity measurements of high-k film substrates at frequencies of 100 Hz to about 10 GHz. In order to analyze the effect of the dielectric thickness, dielectric constant, loss and conductive loss on the impedance characteristics, we used a High Frequency Structure Simulator to perform a full wave numerical analysis of several power planes. Small angle neutron scattering (SANS) was used to probe the dispersion of SWNTs in polymer matrices. It was found that organic-ceramic composites exhibit an intrinsic high frequency relaxation behavior that gives rise to frequency dependent dielectric loss. The highest frequency relaxation process dominates the overall loss characteristic. In the case of polymers modified with SWNTs, we observed that 2% mass fraction of p-doped semi-conducting SWNTs increases the dielectric constant by 3 orders of magnitude, in apparent violation of the mixing-rule. The hybrid material appears to have preferential coupling within the dispersed phase. The experimental data and numerical simulation indicate that these materials can play a significant role as embedded passive devices with functional characteristics superior to that of discrete components.

Single-phase Ba(Cd1/3Ta2/3)O3 ceramics have been produced using conventional powder processing methods. In our initial investigations, 2wt% ZnO powder was added to act as a sintering aid since a high-density ceramic was not formed from solid-state diffusion alone. The resulting Ba(Cd0.327Zn0.006Ta2/3)O3 material sintered at 1550° C exhibits a dielectric constant of ∼33 and loss tangent of <5×10−5 at 2 GHz. In our more recent work, we have used boron as a sintering aid to facilitate sintering at temperatures as low as 1300° C, enhance the structural quality and improve the microwave properties of Ba(Cd1/3Ta2/3)O3 dielectrics. TEM results indicate that the liquid sintering mechanism is an important factor for boron concentrations exceeding 0.5wt%, while a point defect mechanism plays the dominant role at lower boron concentrations. The presence of superstructure peaks and splitting of the (220) and (214) peaks in X-ray diffraction spectra are direct evidence for the distortion from cubic symmetry as a result of Cd and Ta ordering on the B-site.

Ab-initio electronic structure calculations within the local density functional approximation have been used to give insight into the unusual properties of this class of materials. In both Ba(Zn1/3Ta2/3)O3 and Ba(Cd/3Ta2/3)O3, the conduction band maximum and valence band minimum are composed of mostly weakly itinerant Ta 5d-and Zn-3d/Cd-4d levels, respectively. The covalent nature of the directional d-electron bonding in these high-Z oxides plays an important role in producing a more rigid lattice with higher melting points and enhanced phonon energies, and possibly inherently lower intrinsic microwave loss than comparable ionic materials.

AC Coupled Interconnection (ACCI), in conjunction with buried solder bump technology, provides a method to achieve signal I/O pitches of less than 75 μm and signaling rates greater than 5 Gbps per I/O on integrated circuits, while preserving excellent signal integrity. This paper presents a summary of approaches, status, and discusses material issues important to performance.

Many new electronic systems require very high-density packaging to meet system volume and weight constraints. The Chip Scale Package (CSP) is often used to meet this need. However, the limited commercial availability of die in CSP form frequently drives system designers to pursue custom CSP fabrication. Long lead times and manufacturers' reluctance to run small batches typically limit the use of custom CSPs to high volume applications. This paper presents an approach for the rapid prototype of Low Temperature Co-fired Ceramic (LTCC) CSPs.

Integral to the approach is the concept of using a small family of generic substrate designs to build a large variety of CSPs. The generic substrates may be fabricated and kept on hand until a CSP application need arises. When it does, a 12-to-16-week industry-typical lead time does not apply; the CSP may be fabricated rapidly, on site. Fabrication consists of simply singulating the substrate, populating the solder ball pads, mounting and wire bonding the die, encapsulating the substrate surface, and laser marking the assembly. The lead time may be slashed from several months to just a few days.

The family of substrate designs will be described. The substrates, with gold-based interconnects, have standard JEDEC Ball Grid Array (BGA) footprints of either 0.8 mm or 1.0 mm pitch. Substrates have a top surface metallization scheme of either a large central die bond pad surrounded by a number of peripheral bond sites for wire bonds, or a blanket metallization layer that may be patterned, via photolithography, to accommodate a specific application at the time of need. The die pad design is used for CSPs with a single die, while the blanket metallization design is patterned for hybrid or multi-die applications. The design approach, custom photopatterning and gold etch, and assembly processes are presented.

This presentation describes the basics of Multi-Mix® and Green Tape™ Low Temperature Cofired Ceramic (LTCC) technologies. The design and performance of a 28 GHz mixer package using a GaAs MMIC and the 943 Green Tape™ LTCC system with embedded capacitance technology is described including the tradeoffs, advantages and compatibility of Multi-Mix® and Green Tape™ technologies. A design approach combining the technologies offers the designer new options to meet the ever-increasing demands of high frequency packaging.

In this paper, a novel approach for fabricating low cost capacitive RF MEMS switches using directly photodefinable high dielectric constant metal oxides has been developed. In this approach, a radiation sensitive metal-organic precursor is deposited via spin coating and converted patternwise to a high dielectric constant metal oxide via ultraviolet exposure. The feasibility of this approach is demonstrated by fabricating bridge-type and cantilever-type switches with a nitride/metal-oxide/nitride dielectric film stack. These switches exhibited significantly higher isolation and load capacitances as compared to comparable switches fabricated using a simple silicon nitride dielectric.

In this paper, the BaTiO3 nanoceramics have been fabricated by pressureless sintering for the first time. High purity BaTiO3 powders in nano-size of 50∼80nm synthesized by wet chemical method were used to fabricate nanoceramics. The addition of an appropriate amount of Nb2O5 and Co3O4 was found to suppress the grain growth, which is normally encountered in the conventional pressless sintering. The effects of Nb2O5 and Co3O4 on the phase structure, microstructure and dielectric properties of the sintered ceramics were investigated. The BaTiO3 ceramics with the average grain size less than 100nm were achieved after sintering below 1220°C with dielectric constant up to 2000 at room temperature, which is of cubic structure and meets the requirement of X7R specification.

Al-Si wires are often used to make contact to bond-pads of semiconductor chips and devices. During operation in certain types of devices the wires typically reach relatively high temperatures. Under such circumstances, the oxidation could lead to a decrease of wire conductivity. It is of interest therefore to understand the oxidation behavior of the bond wires, particularly at elevated temperatures. In the current study, Al-Si wires were characterized as received from the supplier, and after thermal annealing at 240°C and 300°C. The surface oxides were found to evolve from a single-layer oxide to a double-layer oxide with varying chemistry. Oxide thicknesses were substantially lower than the wire diameter, even after 3000 hours of annealing. Therefore oxidation of the Al-Si wires has an insignificant impact on their electrical conductivity.

(Bi3xZn2−3x)(ZnxNb2−x)O7 thin films (x=1/2 and 2/3) have potential great for tunable RF and microwave devices due to medium dielectric constant and low dielectric loss. The tunable dielectric properties of Bi-rich, (Bi1.5 Zn0.5)(Zn0.5 Nb1.5)O7 thin films were investigated. To make Bi-rich cubic pyrochlore thin films, Bi2O3–ZnO–Nb2O5 monoclinic pyrochlore ceramic targets were used in reactive RF magnetron sputtering process. Substrate heating was employed to improve surface morphology and tunability. As-deposited films were crystallized or amorphous state depending on substrate temperature. All films were annealed at 600°C ∼ 800°C for 3 hours in the air. There were no zinc niobate secondary phases in the films before and after post-annealing, while quite significant amount BZN thin films were found in sputtered using cubic pyrochlore ceramic targets, especially after post-annealing. It was found that Bi-rich BZN films have much larger tunability when as-deposited phase are amorphous. The maximum tunability 38% was obtained when substrate is heated to 350°C and composition of films is close to exact stoichiometric cubic BZN.

As CPUs increase in performance, the numbers of passive components on the surface of the boards are increasing dramatically. To reduce the number of components, as well as improve the electrical performance (i.e. reduce inductance), designers are increasingly embedding capacitive layers in the Printed Circuit Board (PCB).

The majority of the products in use today utilize reinforced epoxy laminates. These products are relatively easy to handle and provide good electrical performance, but a need exists for even better performance than a fiberglass-reinforced product can produce.

Other materials are being developed that are thinner (and thus increase capacitance and reduce inductance), but either have problems with dielectric breakdown strength, handling or only marginal improvements over the reinforced epoxy material. A need exists for an ultra-thin (less than 25 micron) material that not only provides improved electrical performance, but can be readily manufactured using standard PCB processing.

We will discuss the design criteria we used for developing our family of products, as well as the results. The design of the conductor (copper foil) has been determined to be as critical as the properties of the dielectric (polymer). Examination of the effect of loading the polymer with High Dk ferroelectric particles will also be examined.

The products have been through both internal and external testing and are compared to existing and developing capacitor materials. We will describe the electrical as well as the processing characteristics in detail, and how these types of products can greatly improve performance of high-speed systems

This preliminary work reports the preparation of AlN thin films on an LTCC (low temperature co-fired ceramics) substrate by pulsed dc reactive magnetron sputtering and the limited characterization focusing on microstructure and crystal orientation. The main focus will be placed on the effects of changing pulsed frequency. The AlN thin film showed good adhesion with the substrate and columnar structures having small grains regardless of pulsed frequency. The crystal orientation of AlN thin films was dependent on pulsed frequency according to the result of XRD patterns. The preferred (002) orientation was obtained at a pulsed frequency of 100 kHz. The broad band of 300 to 650 nm observed in photoluminescence spectrum was believed due to defects associated with the presence of oxygen impurities.

Selective RF filters based on solidly mounted thin film bulk acoustic wave resonator filters (SMR filters) are of great interest for mobile and wireless applications in the GHz frequency range. They are small in size, robust and can be integrated on silicon. The SMR configuration comprises a textured piezoelectric layer of AlN or ZnO sandwiched between two electrodes, and an acoustic reflector, which confines the acoustic energy in the resonator region. The bulk acoustic wave (BAW) resonators are exited in the thickness extensional mode. In these paper examples of BAW resonators and filters for the frequency range between 1 and 8 GHz are shown. It will become clear that precise control of AlN film growth is very important. Modelling the resonator performance using a 1-dimensional electro acoustical model allows the extraction of important thin film parameters and thus simulation of the filter performance. Limitations of the 1-D model are discussed.