Packaging is rapidly becoming an area of microelectronics technology, which can limit the operating speed on an integrated circuit. To address this concern, much research and development attention now focuses on packaging in an effort to prevent it from impeding the speed of electronic system.

Electronic packaging is defined as the electronic discipline of designing a protective enclosure for an electronic circuit so that it will both survive and perform under all environmental conditions. In the past, the term “electronic packaging” referred to a small number of formats for encasing electronic components, including integrated circuits, so they could readily and reliably be installed in electronic end-products. The principal packaging types was through hole, surface mount, tape automated bonding, and single-chip.

Production of high quality, low-cost consumer electronics product is dependent on proficiency in electronic packaging technologies. Continuous improvement of packaging and related technologies has provided the impetus for development of new and improved consumer product; likewise, consumer demand for new and improved electronic products at reasonable prices has provided the impetus for development of increasingly sophisticated electronic packaging. Packaging is important for signal and power transmission, heat dissipation, electromagnetic interference shielding and protection from environmental factors such as moisture, contamination, hostile chemicals and radiation.

Levels of Packaging
Typical electronic package consists of a hierarchy of interconnections that can be divided up into levels ranging from 0 to 6. The first level package is the most important of all levels because it contains only a single die. The first level package consists of lead frame, die, die attach, wire bond, and encapsulant. The lead frame includes both the lead paddle and lead finger. The lead paddle is used to mechanically support the die before encapsulation while the lead finger allows for electrical contact between the package and circuit board. The die attach material permits heat conduction while assuring mechanical stability of the die. The encapsulant is either a polymer or ceramic, depending on cost and the environment in which the package is used.

The package family selected for an electronic application is dependent on the chip power, size and weight requirements of the system, electrical performance, and lead count requirements.

Package Family	Characteristics	Package Type
In- Line	Leads on one or two sides of package	SID, PDIP, CERDIP
Small Outline	Leads on two or four sides, small body	SOJ, SOP, TSOP
Quad Surface Mount	Leads on four sides package Larger package dimension High lead counts	PLCC, PQFP, LDCC, CERQUAD
Grid Array	Pin or ball array placed on package body Very high lead count	PPGA, PLGA, PBGA

System Type
Three principal system types have been identified, each of which appears to make different demands on packaging: low-end digital, high-end digital, and high speed. Low-end digital systems typically use silicon MOS circuits packaged separately, with printed wiring boards for chip interconnection. High-end digital systems typically use silicon bipolar technology, often with packages in modules that carry many chips. The advent of bipolar complementary technology blurs the distinction between the two digital system types. High-speed circuits typically use gallium arsenide chips.

Packaging Approaches
The two main approaches currently used to achieve high-density electronic packaging are the printed wiring board (PWB) approach and the thick-film multichip module (MCB) approach. In the PWB approach, single chip modules, the first packaging level, are assembled on a printed wiring board. The second packaging level is the individual packages by either through hole or surface mounting using soft solder joints. In the thick film MCM approach, multichip modules contain multiple bare chips jointly packaged in a ceramic package that is constructed by multilayering thick film conductor layers and ceramic dielectric layers.

Applications
The electronic packaging is commonly defined as “all parts of an electronic system with the exception of the integrated devices”. The electronic system itself may be a personal computer, laptop, server or a workstation. Systems also include many consumer electronics, appliances, automobiles, weapon systems, airplanes, medical diagnostic and surgical instruments and bio-medical devices. Typical hardware that would be considered a part of the electronic package includes printed circuit boards, chip carriers, connectors, cables, power supplies, fans and blowers and the system box or chassis among many others. The packaging not only includes the hardware and software used in the electronic system but also includes the manufacturing and assembly processes for the components and the system.