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Analysis of the characteristics and advantages of semiconductor packaging

◆◆ One, DIP dual in-line package ◆◆


DIP package

DIP refers to integrated circuit chips packaged in dual in-line form. Most small and medium-sized integrated circuits (ICs) use this type of package, and the number of pins is generally less than 100. CPU chips in DIP packages have two rows of pins that need to be plugged into a chip socket with a DIP structure. Of course, it can also be directly inserted on a circuit board having the same number of holes and geometric arrangement for soldering. The DIP-packaged chip should be carefully handled when plugging or unplugging from the chip socket, and the pins are damaged in the face.

The DIP package has the following features:

1. Suitable for perforation welding on PCB (printed circuit board), easy to operate

2. The ratio between the chip area and the package area is large, so the volume is also relatively large.

The 8088 in the Intel family of CPUs is in this form of packaging. Cache and early memory chips are also in this package.

◆◆2, QFP plastic square flat package and PFP plastic flat component package ◆


QFP package

The QFP (Plas ti c Quad Flat Package) package has a small distance between the chip pins and a very thin pin. Generally, large-scale or very large integrated circuits are used in this package, and the number of pins is generally more than 100. Chips packaged in this form must be soldered to the motherboard using SMD (Surface Mount Device Technology). Chips mounted with SMD do not have to be perforated on the motherboard. Generally, solder joints of corresponding pins are designed on the surface of the motherboard. The soldering to the motherboard can be achieved by aligning the legs of the chip with the corresponding solder joints. Chips soldered in this way are difficult to disassemble without special tools.

The chip packaged in the PFP (Plastic Flat Package) mode is basically the same as the QFP mode. The only difference is that the QFP is generally square, and the PFP can be either square or rectangular.

The QFP/PFP package has the following features:

1. Applicable to SMD surface mount technology to install wiring on PCB circuit board.

2. Suitable for high frequency use.

3. Easy to operate and high reliability.

4. The ratio between the chip area and the package area is small.

The 80286, 80386 and some 486 motherboards in the Inte l series CPUs are available in this package.

◆◆Three, PGA pin grid array package ◆◆

The PGA (Pi n Grid Array Package) chip package has a plurality of square-shaped pins inside and outside the chip, and each of the square-shaped pins is arranged at a certain distance along the circumference of the chip. Depending on the number of pins, you can enclose 2-5 turns. When installing, plug the chip into a dedicated PGA socket. In order to make the CPU more convenient to install and disassemble, starting from the 486 chip, a CPU socket called ZIF appears to meet the requirements of the PGA package CPU installation and disassembly.

ZIF (Zero Insertion Force Socket) refers to a socket with zero insertion force. By gently lifting the wrench on the socket, the CPU can be easily and easily inserted into the socket. Then, the wrench is pressed back to the original position, and the pin of the CPU is firmly contacted with the socket by the pressing force generated by the special structure of the socket itself, and there is absolutely no problem of poor contact. To remove the CPU chip, simply lift the wrench of the socket gently, and the pressure is released, and the CPU chip can be easily removed.

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PGA package

The PGA package has the following features:

1. The insertion and removal operation is more convenient and the reliability is high.

2. Can adapt to higher frequencies.

In the Intel series CPU, the 80486 and Pentium, Pentium Pro are all in this package.

◆◆4, BGA ball grid array package ◆◆

With the development of integrated circuit technology, the packaging requirements for integrated circuits are more stringent. This is because the packaging technology is related to the functionality of the product. When the frequency of the IC exceeds 100MHz, the traditional packaging method may produce the so-called "CrossTalk" phenomenon, and when the number of pins of the IC is more than 208 pins, the conventional packaging method has Its difficulty. Therefore, in addition to using the QFP package, most of today's high-end chips (such as graphics chips and chipsets) are switched to BGA (Ball Grid Array Package) packaging technology. As soon as the BGA emerged, it became the best choice for high-density, high-performance, multi-pin packages such as CPUs and South/North Bridge chips on the motherboard.

BGA packaging technology can be divided into five categories:


BGA package

1. PBGA (Plasric BGA) substrate: generally a multilayer board composed of 2-4 layers of organic materials. In Intel series CPUs, Pentium II, III, and IV processors are available in this package.

2. CBGA (Ce ram icBGA) substrate: the ceramic substrate, the electrical connection between the chip and the substrate is usually flip-chip (FlipChip, FC for short) installation. In the Intel series CPUs, Pentium I, II, and Pentium Pro processors have been used in this package.

3. FCBGA (Fi lpC hipBGA) substrate: a rigid multilayer substrate.

4. TBGA (TapeBGA) substrate: The substrate is a strip-shaped soft 1-2 layer PCB circuit board.

5. CDPBGA (Carity Down PBGA) substrate: refers to the chip area (also called cavity area) with a square depression in the center of the package.

The BGA package has the following features:

1. Although the number of I/O pins is increased, the distance between the pins is much larger than that of the QFP package, which improves the yield.

2. Although the power consumption of the BGA is increased, the electrothermal performance can be improved due to the controlled collapse chip method.

3. The signal transmission delay is small, and the adaptation frequency is greatly improved.

4. Assembly can be used for coplanar welding, and the reliability is greatly improved.

The BGA packaging method has entered the practical stage after more than ten years of development. In 1987, Citizen Corporation of Japan began work on a chip (ie BGA) in a molded ball grid array package. Then, companies such as Motorola and Compaq joined the development of BGA. In 1993, Motorola took the lead in applying BGA to mobile phones. In the same year, Compaq also applied it on workstations and PCs. Until five or six years ago, Intel began using BGA in computer CPUs (ie Pentium II, Pentium III, Pentium IV, etc.) and chipset (such as i850), which played a role in the expansion of BGA applications. At present, BGA has become an extremely popular IC packaging technology. Its global market size is 1.2 billion in 2000. It is expected that the market demand in 2005 will increase by more than 70% compared with 2000.

◆◆ Five, CSP chip size package ◆◆

With the globalization of global electronic products, the demand for lightweight has become a trend, and packaging technology has advanced to CSP (Chip Size Package). It reduces the size of the chip package outline, so that the size of the bare chip is large, and the package size is large. That is, the length of the IC after packaging is not more than 1.2 times that of the chip, and the IC area is only 1.4 times larger than the die.

Csp package can be divided into four categories

1. Lead Frame Type: Representative manufacturers include Fujitsu, 曰立, Rohm, Goldstar, etc.

2. Representative manufacturers include Motorola, Sony, Toshiba, Panasonic, etc.

3.Flexible Interposer Type: The most famous one is Tessera's microBGA, and CTS's sim-BGA uses the same principle. Other representative vendors include General Electric (GE) and NEC.

4.W afe r Level Package: Different from the traditional single chip package method, WLCSP is a single chip that cuts the whole wafer into a single chip. It is called the future mainstream of packaging technology. The companies that have invested in R&D include FCT, Aptos, Casio, EPIC, Fujitsu, and Mitsubishi Electronics.

The CSP package has the following features:

1. Meet the ever-increasing need for chip I/O pins.

2. The ratio between the chip area and the package area is small.

3. Greatly reduce the delay time.

The CSP package is suitable for ICs with a small number of pins, such as memory sticks and portable electronics. In the future, it will be widely used in emerging products such as information appliances (IA), digital television (DTV), e-books, wireless networks WLAN/GigabitEthemet, ADSL/mobile phone chips, and Bluetooth.

◆◆ Six, MCM multi-chip module ◆◆

In order to solve the problem of low integration and insufficient function of a single chip, a plurality of highly integrated, high-performance, high-reliability chips are used to form a variety of electronic module systems on a high-density multilayer interconnection substrate using SMD technology. Thus, an MCM (Multi Chip Model) multi-chip module system has appeared.

MCM has the following characteristics:

1. The package delay time is reduced, and the module can be speeded up easily.

2. Reduce the package size and weight of the whole machine/module.

3. System reliability is greatly improved.

In short, due to the continuous development of CPUs and other very large integrated circuits, the package form of integrated circuits has been continuously adjusted and changed, and the advancement of package form will in turn promote the advancement of chip technology