Thick‐Film Fundamentals

Abstract

Engineers and scientists adopt materials and energy to society's needs. Since all disciplines in engineering and science involve the design of technical products, and all engineering disciplines encounter materials, it is essential to learn the properties and behavior of the types of materials used in a particular engineering product. Similarly, thick-film hybrid microcircuitry, which represents a packaging approach for electronic components intermediate between the conventional assembly of discrete components mounted on a printed board and monolithic integrated circuits is dependent on materials [1]. A thick-film hybrid microcircuit has components such as resistors, capacitors, and conductors, which are screen printed on alumina substrate [2,3]. The film resistor and the conductor used in a thick-film hybrid circuit are composed of mixtures of particulates of metals, metal oxides, and fine glass powders suspended in organic binders. The dielectric paste (ink), on the other hand, is composed of insulating materials such as oxides of metals and semiconductors and fine glass powders suspended in organic binders. Proper handling of these materials depends on knowledge of their physical, chemical, mechanical, and electrical properties. The e¤ect that one material may have on another material within a hybrid circuit is of extreme concern [4]. Therefore, material substitutions that are being contemplated should be reviewed to determine whether a material selected is susceptible to malfunction under harsh conditions. Nonconforming materials can result in failure of hybrid circuits caused by one or more of the following: metal migration [5], corrosion or oxidation [6], ionic contamination [7,8], improper adhesion [9], intermetallic formation [6,10], and di¤erences in thermal 126 Handbook of Thick-and Thin-Film Hybrid Microelectronics,