The paper presents general information on LTCC materials, manufacturing processes and properties of fired modules. A Multichip Module package has been the main application of Low Temperature Cofired Ceramic (LTCC) technology. Recently, this technology is also used for production of sensors, actuators and microsystems. The research and development on the LTCC sensors and microsystems carried out in the Laboratory of Thick Film Microsystems at Wroclaw University of Technology are presented. LTCC microfluidic system is described in detail. Moreover, a short information is given on other LTCC applications .

Technology and applications of Low Temperature Cofired Ceramic (LTCC) based sensors and microsystems

/pdf/handbook-of-advanced-materials-1kqmvc4p7z.pdf

Handbook of Advanced Materials

Monolithic inductors are widely used in microwave ICs and RFICs. Design considerations for inductors on low-resistivity substrates have been described. A /spl pi/-equivalent model, used to account for various loss mechanisms, can be helpful in understanding differences in the definition of L and Q for single-ended and differential structures that exist in the literature. Specific uses for the equations in this article have been outlined. The L and Q for an example monolithic, differential inductor were extracted from measured two-port S-parameters using equations for differential configurations on low-resistivity substrates.

Quality factor and inductance in differential IC implementations

A package is made of a transparent substrate (12) having an interferometric modulator (10) and a back plate (30). A non-hermetic seal (32) joins the back plate to the substrate to form a package, and a desiccant (34) resides inside the package. A method of packaging an interferometric modulator includes providing a transparent substrate and manufacturing an interferometric modulator array on a backside of the substrate. A back plate is provided and a desiccant is applied to the back plate. The back plate is sealed to the backside of the substrate with a back seal in ambient conditions, thereby forming a package.

Packaging for an interferometric modulator

Corrosion control in electronics and know-how concerning various protection methods have become an important field of design since electronics is increasingly used as integrated into different devices in highly corrosive conditions. On the other hand, the increase of the packaging density of electronics has resulted in electronics that is sensitive to the corrosive effects of the environment even in milder conditions. The project charted the mechanisms through which the climate, humidity, contamination, other environmental factors, the way of use of the device and its structure as well as the manufacturing process affect the corroding and faults of the electronics. A method was developed for solving these problems by which both the experienced and the beginning designer can check the feasibility of the applied corrosion protection technique and foresee possible corrosion problems in the structure of the device as well as find new approaches for solving them. The report also presents an evaluation method for the corrosive effect of the usage environment. In addition, various types of corrosion mechanisms and protection against them are described, corrosion analysis and measurement methods introduced and testing methods used for quality assurance regarding corrosion discussed. Comprehensive lists of standards and literature concerning corrosion and climatic effects are appended to the report. This report is available in English and in Finnish (VTT Publications 623, http://virtual.vtt.fi/inf/pdf/publications/2007/P623.pdf)

Corrosion and climatic effects in electronics

Opto-electronic and MEMS packages require unique capabilities over and above traditional hermetic multichip modules. In addition to hermeticity or vacuum atmosphere, opto-electronic systems require direct input/output of optical, RF and other sensitive signals through the package using fiber-optic, coaxial and/or other interconnection approaches. Precise optical component alignment and accurate thermal management is critical to achieve component and system performance capabilities. Furthermore, to improve MEMS functionality, performance and service life, a suitable getter and/or dopant is required compatible with the hermetic/vacuum package atmosphere. The getter/dopant is usually activated after achieving hermetic or vacuum atmosphere. A comprehensive MEMS packaging approach is introduced based on photo-patterned thick film metallization, LTCC, brazing technology and new feed-through approaches. The new methodology incorporates most reported MEMS packaging requirements for proven performance, reliability, low cost and mass production capabilities.

A new approach for opto-electronic/MEMS packaging

Recognizing the need for improved materials data to meet the needs of designers of RF and microwave products, DuPont Photopolymers and Electronic Materials (P&EM) has had an ongoing program to generate high frequency data on materials properties (dielectric constant, loss tangent and attenuation). Characterization of ceramic and printed wiring advanced interconnection materials in the 1 to 20 GHz range has been performed for a variety of new Thick Film and Low Temperature Cofired Ceramic (LTCC) dielectrics. Gold and silver conductors applied by both screen printing and photopatterning on these dielectrics as well as on 96% alumina have been tested. These have been benchmarked against Thin Film conductors and copper clad FR-4, Polyimide, BT and Teflon/sup (R)/ printed wiring materials. The performance of many of these systems has been reported for room temperature and humidity conditions. This presentation builds on the previous work with data on the high frequency properties of some of the advanced ceramic and printed wiring materials systems when exposed to 85/spl deg/C temperature and 85% relative humidity. In addition the high frequency performance of a new gold conductor system with both screen printed and photoetched patterning on 96% and 99% Alumina is described demonstrating the improved performance over gold Thin Film metallization typically used in Microwave applications.

High frequency electrical characterization of electronic packaging materials: environmental and process considerations

The development of brazing interconnection technology to low thermal expansion glass-ceramics is discussed in detail. A two-paste thick-film metallization system which acts not only as a chemical barrier to the braze alloy, but also as a high-ductility stress cushion to reduce joining stresses on the glass-ceramic was developed along with a braze alloy paste with enhanced ductility and wettability. Results of studies on joining Kovar, Invar, and Platinite-2 (with temperature coefficient of expansion (TCE) ranging from 1.5 to 5.5 ppm//spl deg/C) to low TCE glass-ceramics are presented. Attention is given to the development of process and design guidelines which were driven by the stringent demand on limiting the total stress so that the combined stresses generated from thick-film metallization, braze joint, and adhesion strength do not exceed the fracture strength of the glass-ceramic. Process conditions that allow the post thin-film multilayer metallization of the cofired glass-ceramic, thus combining the capabilities of both MCM-C's and MCM-D's for high-performance multichip packaging, was developed. Thermal cycling reliability data for two multichip modules (MCMs) with brazed pins, leads, and large windowframe are also discussed. >

http://ieeexplore.ieee.org/iel2/1029/8043/00346745.pdf

Development of brazing interconnection to low thermal expansion glass-ceramics for high performance multichip packaging

A new "high density" gold thick film technology is introduced. Circuits produced using the new material system exhibit superior fine line definition, conductivity density and high frequency performance. The high frequency performance of etched "high density" gold circuits were found to be superior to etched thin film circuits in the GHz range.

New low cost interconnection materials for high frequency MCM applications

A new High Density gold thick film technology is introduced. The new technology is based on a new submicron gold powder technology which is used in the formulation ofa new class of gold thick film compositions. Circuits produced by using the new High Density gold thick film compositions exhibit superior fine line definition, conductivity, backlit density and high frequency performance when compared to standard gold thick film compositions. The density, conductivity and high frequency performance of the new High Density gold thick film compositions were found to be equivalent to those produced by thin film gold deposition methods. Ultra fine line widths of 10 microns can be produced by etching the fired High Density gold thick film.

R.L. Keusseyan

Papers

A new approach for opto-electronic/MEMS packaging

High frequency electrical characterization of electronic packaging materials: environmental and process considerations

Development of brazing interconnection to low thermal expansion glass-ceramics for high performance multichip packaging

New low cost interconnection materials for high frequency MCM applications

High density gold thick film technology