Editing Integrated circuit (section)

=== Packaging ===
{{Main|Integrated circuit packaging}}
[[File:RUS-IC.JPG|right|thumb|A Soviet MSI [[NMOS logic|nMOS]] chip made in 1977, part of a four-chip calculator set designed in 1970<ref>{{cite web | url=http://www.155la3.ru/k145_3.htm#k145hk1 | title = 145 series ICs (in Russian) | access-date=22 April 2012 }}</ref>]]

The earliest integrated circuits were packaged in ceramic [[Flatpack (electronics)|flat packs]], which continued to be used by the military for their reliability and small size for many years. Commercial circuit packaging quickly moved to the [[dual in-line package]] (DIP), first in ceramic and later in plastic, which is commonly [[cresol]]-[[formaldehyde]]-[[novolac]]. In the 1980s pin counts of [[Very Large Scale Integration|VLSI]] circuits exceeded the practical limit for DIP packaging, leading to [[pin grid array]] (PGA) and [[leadless chip carrier]] (LCC) packages. [[Surface-mount technology|Surface mount]] packaging appeared in the early 1980s and became popular in the late 1980s, using finer lead pitch with leads formed as either gull-wing or J-lead, as exemplified by the [[Small Outline Integrated Circuit|small-outline integrated circuit]] (SOIC) package – a carrier which occupies an area about 30–50% less than an equivalent DIP and is typically 70% thinner. This package has "gull wing" leads protruding from the two long sides and a lead spacing of 0.050&nbsp;inches.

In the late 1990s, [[PQFP|plastic quad flat pack]] (PQFP) and [[Thin Small Outline Package|thin small-outline package]] (TSOP) packages became the most common for high pin count devices, though PGA packages are still used for high-end [[microprocessor]]s.

[[Ball grid array]] (BGA) packages have existed since the 1970s. [[Flip chip|Flip-chip Ball Grid Array]] packages, which allow for a much higher pin count than other package types, were developed in the 1990s. In an FCBGA package, the die is mounted upside-down (flipped) and connects to the package balls via a package substrate that is similar to a printed-circuit board rather than by wires. FCBGA packages allow an array of [[Input/output|input-output]] signals (called Area-I/O) to be distributed over the entire die rather than being confined to the die periphery. BGA devices have the advantage of not needing a dedicated socket but are much harder to replace in case of device failure.

Intel transitioned away from PGA to [[land grid array]] (LGA) and BGA beginning in 2004, with the last PGA socket released in 2014 for mobile platforms. {{As of|2018}}, AMD uses PGA packages on mainstream desktop processors,<ref>{{Cite news|url=https://wccftech.com/amd-am4-socket-zen-bristol-bridge-soc-package-pictured/|title=AMD Zen CPU & AM4 Socket Pictured, Launching February 2017 – PGA Design With 1331 Pins Confirmed|last=Moammer|first=Khalid|date=2016-09-16|work=Wccftech|access-date=2018-05-20}}</ref> BGA packages on mobile processors,<ref>{{Cite news|url=https://en.wikichip.org/wiki/amd/ryzen_5/2500u|title=Ryzen 5 2500U – AMD – WikiChip|access-date=2018-05-20|publisher=wikichip.org}}</ref> and high-end desktop and server microprocessors use LGA packages.<ref>{{Cite news|url=https://www.pcworld.com/article/3198924/computers/amds-tr4-threadripper-cpu-socket-is-gigantic.html|title=AMD's 'TR4' Threadripper CPU socket is gigantic|work=PCWorld|access-date=2018-05-20|author=Ung, Gordon Mah |date=May 30, 2017}}</ref>

Electrical signals leaving the die must pass through the material electrically connecting the die to the package, through the conductive [[signal trace|traces]] (paths) in the package, through the leads connecting the package to the conductive traces on the [[printed circuit board]]. The materials and structures used in the path these electrical signals must travel have very different electrical properties, compared to those that travel to different parts of the same die. As a result, they require special design techniques to ensure the signals are not corrupted, and much more electric power than signals confined to the die itself.

When multiple dies are put in one package, the result is a [[system in package]], abbreviated {{Abbr|SiP|System in Package}}. A [[multi-chip module]] ({{Abbr|MCM|multi-chip module}}), is created by combining multiple dies on a small substrate often made of ceramic. The distinction between a large MCM and a small printed circuit board is sometimes fuzzy.

Packaged integrated circuits are usually large enough to include identifying information. Four common sections are the manufacturer's name or logo, the part number, a part production batch number and [[serial number]], and a four-digit date-code to identify when the chip was manufactured. Extremely small [[surface-mount technology]] parts often bear only a number used in a manufacturer's [[lookup table]] to find the integrated circuit's characteristics.

The manufacturing date is commonly represented as a two-digit year followed by a two-digit week code, such that a part bearing the code 8341 was manufactured in week 41 of 1983, or approximately in October 1983.