List of integrated circuit packaging types
The jacket of a semiconductor chip ( a die ) including the connection points (leads, pins or ball) is known as a housing or package. There are many variations of such housing, which differ in their shape, the materials used, the number and arrangement of pins and other features.
This article covers the housing options for integrated circuits, which are for discrete devices in the list of semiconductor packages.
- 4.2.1 Designs for Surface Mounted Device ( SMD)
Standards
The standard range of the chip package by the JEDEC ( Joint Electron Device Engineering Council earlier today JEDEC Solid State Technology Association), the semiconductor standardization body of the EIA ( Electronic Industries Alliance). Basically we distinguish between electronic components wired, " by jack mount " (Through Hole Technology - THT) and " surface mount " (Surface Mounted Technology's - SMT) designs. " Surface Mounted Devices - SMD " refers to a member of the aforementioned group.
Function
A housing serves to mount the semiconductor chip on a circuit board and to connect the integrated circuit on the semiconductor chip, with the components on the circuit board. The main reasons are, firstly, the protection of the against damage. Secondly, the different geometric distances between the electrical connections have to be bridged on one die and a circuit board. The pads ( terminals of the IC die) are bonded by means of gold, copper or aluminum wire to an intermediate material ( attached). This intermediate material is a stamped sheet copper (lead frame ) or a small circuit board that is mentioned in this use substrate. New technologies dispense with wires and use the flip- chip technology. The connection to the printed circuit board is carried out finally to " legs" (pins ) that are part of the lead frame, or over small bumps ( balls ).
After fixing and wiring of the ICs on the intermediate material it is protected by different materials ( plastic, ceramic, metal) hermetically against environmental influences. For cost reasons, plastic is used almost exclusively by injection molding. It can depending on the type of the semiconductor also openings for light (in the case of EPROMs for deletion, in the case of LEDs or laser diodes for the light exit ) share the view of the semiconductor. These openings are usually closed by means of transparent plastic or quartz glass, so that the semiconductor is not directly exposed to the environment. Exception are sensors which have defined openings (eg, light, etc. pressure ) to measure environmental influences.
To improve the heat dissipation of the chip housing some heatsinks ( heat sinks ) have built (especially for power transistors ).
In order to achieve a higher packing density can also Bare Dies ( "bare chips") mounted directly on the circuit board and wrapped there. If different, this packaged in a housing, one speaks of a multi-chip module.
The pins
The grid of pins is called Pitch. Since the first ICs came from the Anglo-American area, were the dimensions on Customs basis. The " standard size " was therefore the duty and for small extent the "mil " was mostly used (one thousandth of an inch = 0.0254 mm or 25.4 microns ). In the course of internationalization, more and more by the metric measurements, so that typical pitches today are at, eg, 0.5 mm.
The pins are usually placed at the lateral edges (e.g., DIP ), or lower (e.g., PGA ) of the housing and have a variety of forms. They are connected by soldering to the circuit board, wherein the different forms of the various support Lötarten. Components in THT housing are typically placed only on the component side of a printed circuit board. The installed package is then soldered by wave soldering ( the underside of the board is removed via a solder bath, produced at the end of the bath by damming a wave, hence the name). By additionally selective soldering THT components can be assembled and soldered on the second side of the PCB. However, this is connected to an additional manufacturing step.
SMD components can be placed both on the component side and on the solder side of the PCB. Then they are soldered on both sides of the printed circuit board by reflow soldering, or vapor phase soldering. Alternatively, SMD components can be soldered by wave soldering. For this, they must be located on the solder side. The components must be of a wave loosens, that is the case and the component to the solder bath must endure. Also the pins through the solder must not be short-circuited. Here are the Pinformen and spacing of critical importance so that only a few SMD types, where the distances are as large as possible, are suitable for this type of soldering. ICs with pins on all four sides of the enclosure must be preferably aligned diagonally to the direction of work in wave soldering, etc. so that as few solder bridges.
Some of the pins are also used to insert the IC into a socket so that the IC does not need to be soldered. ( However, it still needs the socket to be soldered. )
For some components (particularly powerful microprocessors) is the number of pins so high that the pages are no longer sufficient to accommodate the legs. Therefore modern ICs often have no more pins on the sides, but they are fixed with pins or solder balls on the underside of the housing ball grid array ( BGA ) on the circuit board. When the solder balls that works only by reflow soldering. The pins on the bottom usually wave soldering is used.
Various types of
Since the JEDEC designations are not very catchy, simple abbreviations have prevailed in the industry, which can be described as quasi- standard. This largely acronyms are used that describe the actual design.
Lead frame -based housing (English leadframe based packages)
Designs for through hole technology (THT )
Designs for Surface Mounted Device ( SMD)
Substrate -based housing
Designs for Surface Mounted Device ( SMD)
Special forms
Gallery
- Different chip package
DIL28 UV ST6E15 1989
Piggyback40 Toshiba TLCS90 Family 1988
DIL18 Microchip PIC16F84
Atmel AT90S2333 DIL28
ZIP19 (20 ) Toshiba DRAM 1990 514256
ZIP28 Toshiba VideoRAM 524256 1992
TO-5 metal housing, OP: 1979
PGA 6x86 IBM
PGA AMD
PGA AMD 486DX2, opened with views of the The
CPGA and PPGA Pentium family
Power DIP, Power -SO
BGA16 (NEC 78K0S ) and SOT23 -6 ( Microchip PIC)
Various SMD components
SO20 UV ST6E20, 1992
CRQFP80 UV erasable ST62E40, 1993
TQFP216 AMD Am286LX/ZX (SoC )
Bumped TQFP132 the Intel i386SL
U80701 in CQFP housing with support
PLCC20 (28 ) IBM Memory 1991
PLCC68 80286 Siemens 1989
Cypress PLCC84 UV FPGA, 1996
CLCC68: Intel R80C188XL. Links seen from above and to the right of the bottom
LGA775
CQFN44 Harris 82C55, 1993
TQFP Lead Frame
DIP16 leadframe
EPROM through the ' bull's eye '
80486 The in the open housing
SOT23 or SC70 still not soldered in the solder paste
Various SMD components ( SO8 and DPAK )
Printed circuit board, memory module or SIMM ( PLCC18 )
BGA: Embedded Intel Pentium MMX
FBGA: two CPLDs on a USB plug
Plastic DIL64: Thomson TS68000 ( = Motorola MC68000 )
Ceramic DIL40: AMI S6800 ( = Motorola MC6800 )
PCB, Slot -A Athlon AMD
Intel Pentium than TCP version
SOT23- 6 package