At present, the packaging method of CPU is basically PGA packaging. There are many layers of square pins under the chip, and each square pin is arranged at a certain distance along the periphery of the chip. Its pins look like needles and are combined with the circuit board in the form of plug-ins. When installing, insert the chip into the dedicated PGA socket. The advantage of PGA package is more convenient plugging and unplugging operation and high reliability, but the disadvantage is high power consumption. Since the 486 chip, ZIF (Zero Insertion Force Socket) CPU socket has appeared, which is specially used to install and disassemble the CPU packaged by PGA.
PGA also derived a variety of packaging methods. PGA (Pin Grid Array) package is suitable for Intel Pentium, Intel Pentium PRO and Cyrix/IBM 6x86 processor SPGA package, and AMD K5 and Cyrix MII processor CPGA (Ceramic Pin Grid Array) package. It is suitable for the packaging of Intel Pentium MMX and AMD K6. AMD K6-2。 AMD K6 III, VIA Cyrix III, Cyrix/IBM 6x86MX, IDT WinChip C6 and IDT WinChip 2 processors PPGA (plastic pin grid array). It is suitable for FC-PGA (Flip Chip Pin Grid Array) packaging of Intel Celeron processor (Socket 370) and Coppermine series Pentium III, Celeron II and Pentium 4 processors. 2.SEC (single-sided card box) package
Solt X CPU is no longer encapsulated in ceramics, but a printed circuit board with a metal shell and integrated processor components. The plastic packaging shell of SEC card is called SEC (Single Side Contact Card Box) single side card box. This SEC card is designed to be inserted into slot X (about the size of ISA slot). All Slot x motherboards have a fixing device consisting of two plastic brackets, and the SEC card can be inserted into the Slot X slot between the two plastic brackets.
Among them, Intel Celeron processor (slot 1) is packaged with (SEPP) single-sided processor, and Intel Pentium II is packaged with SECC (single-sided contact connector). Intel Pentium III is packaged in SEC2.
Second, the packaging method of the chipset The main packaging method of the chipset is BGA or PQFP. 1.BGA (ball grid array) ball matrix array package
BGA package is in the form of a thin needle drawn from the bottom, so it must be welded by controlled chip collapse (C4 welding for short). For our common motherboard chipset, what we actually see is not the size and appearance of the chip that really works, but what the chip is packaged into. This kind of packaging is necessary and crucial for the chip. Because the chip must be isolated from the outside world, to prevent impurities in the air from corroding the chip circuit, resulting in the decline of electrical performance. On the other hand, the packaged chip is also more convenient to install and transport. The package area of BGA package is only about 1.5 times the surface area of the chip, and the pins of the chip are led out from the center of the chip, which effectively shortens the conduction distance of the signal, so the attenuation of the signal is reduced, and the anti-interference and anti-noise performance of the chip will be greatly improved. Moreover, BGA package is not only smaller, but also thinner (package height is less than 0.8mm). Therefore, BGA has higher thermal conductivity, which is very suitable for long-term running systems and has excellent stability. Although the number of I/O pins in BGA package increases, the pin spacing is much larger than QFP, thus improving the assembly yield. Although the power consumption is increased, BGA can be welded by controlled chipping method to improve its electrothermal performance. It has the advantages of small signal transmission delay, greatly improved use frequency and high reliability. The disadvantage is that BGA package still occupies too much substrate area like QFP and PGA. 2. Plastic square flat package.
There are pins around the chip in PQFP package, and the number of pins is generally above 100, and the pin spacing is very small and the pins are very thin. Generally, large-scale or very large-scale integrated circuits adopt this packaging form. Chips packaged in this way must use SMD (Surface Mount Device Technology) to solder the pins on the chip side to the motherboard. Chip mounted by SMD does not need to be punched on the motherboard, and there are usually designed solder joints corresponding to pins on the surface of the motherboard. By aligning each pin of the chip with the corresponding solder joint, the bonding with the motherboard can be realized. Chips soldered in this way are difficult to disassemble without special tools. PQFP package is suitable for SMD surface mount technology to install wiring on PCB, and is suitable for high frequency use. It has the advantages of convenient operation, high reliability and small ratio of chip area to package area.
Third, the packaging method of BIOS chips At present, most of the BIOS chips on the motherboard are erasable BIOS. The most common packaging methods of BIOS chips are DIP (Dual In-line Package) and PLCC (Molded Lead Chip Carrier Package). In fact, there is no difference in performance between the two packaged BIOS chips, but the size and cost are different. 1.dip (double. dual inline pin package
There are two rows of pins on both sides of the BIOS chip in DIP package, and the number of pins generally does not exceed 100, so it is necessary to insert the chip socket in DIP structure. Of course, according to its pins, it can also be directly inserted into the circuit board with the same number of welding holes and geometric arrangement for welding. DIP package is suitable for punching and soldering on PCB (printed circuit board). PCB wiring is easy and operation is simple, but the disadvantage is that the chip area accounts for a large proportion of the package area. Generally, BIOS chips in DIP package are all packaged in 28 or 32 pins. 2.PLCC (plastic Led chip carrier) plastic lead chip carrier package
There is also a PLCC32 package, which is square in shape, 32-pin package and surrounded by pins, and its overall size is much smaller than that of DIP package. PLCC packaging is suitable for SMT surface mount technology to install wiring on PCB, which has the advantages of small overall size and high reliability.
Fourth, the packaging method of memory The most common packaging methods of memory particles are SOJ, TSOP II, Tiny-BGA, BLP, μBGA, etc. In addition, since SIP and DIP packaging methods are mainly used for early or other configured memory products, they will not be introduced in detail here. The main packaging methods of memory modules are SIMM and DIMM. 1.SOJ (small outgoing j-pin) Small J-pin package
SOJ packaging means that there are a row of small J-shaped pins on both sides of the memory chip, which are directly attached to the surface of the printed circuit board. Edo DRAM is generally packaged in SOJ. 2.TSOP (thin small package) thin small package.
Most SDRAM memory chips are packaged in traditional TSOP. TSOP packaging method refers to a light and small package (the package thickness is only one third of that of SOJ), and pins are made around the package chip and directly pasted on the surface of the printed circuit board. For example, SDRAM's IC has pins on both sides, and SGRAM's IC has pins around it. In TSOP packaging mode, the memory chip is soldered to the PCB through the chip pins, and the contact area between the solder joint and the PCB is small, so it is relatively difficult for the chip to transfer heat to the PCB. Moreover, when the memory in TSOP package exceeds 150MHz, there will be great signal interference and electromagnetic interference. 3. Miniature BGA (Miniature ball grid array) ball grid array package.
The most striking thing about Kingmax memory is the unique Tiny-BGA package, which can reduce the chip area and the PCB area of the whole memory. In fact, Tiny-BGA package can be regarded as subminiature BGA package. The circuit connection of Tiny-BGA package is also different from the traditional way. The connection between the memory chip and the circuit board actually depends on the thin line in the center of the chip. Compared with traditional packaging technology, Tiny-BGA packaging has three major advances: larger capacity (more storage particles can be packaged on the circuit board), better electrical performance (because the connection path between the chip and the backplane is shorter, which avoids the noise of electromagnetic interference and can be suitable for higher working frequency), and better heat dissipation performance (the storage particles are soldered on the PCB through solder balls, and the contact area between the solder joints and the PCB is larger, so the heat generated by the memory chip during working can be very large. )。 4.BLP (bottom lead package) bottom lead package.
The memory particles of ALUKA gold bars are packed by special BLP method. Based on the traditional packaging technology, this packaging technology adopts a reverse circuit, and the pins extend directly from the bottom. Its advantage is that it can save about 90% of the circuit and greatly reduce the package size resistance and chip surface temperature. Compared with the traditional TSOP package, the memory particles are significantly smaller. The BLP package is similar to TINY-BGA package of KINGMAX. The packaging technology of BLP greatly reduces the resistance, chip temperature and stable working frequency. 5.μBGA (Micro ball grid array) Micro ball grid array package.
μBGA package is improved on the basis of BGA. According to the center distance of solder area of 0.5 mm, the ratio of chip area to package area is greater than 1: 1. 14. It is an exclusive patent of Tessera, especially suitable for direct RDRAM working at high frequency, but its manufacturing cost is extremely high. At present, it is mainly used for direct RDRAM. 7.SIMM (single in-line memory module) single built-in memory model.
SIMM module includes one or more RAM chips, which are connected to the motherboard of the computer through pins on a small integrated circuit board. Because users need to expand their memory, they just need to add some new SIMM. 30-line SIMM memory chips appeared earlier. According to the technical requirements at that time, only 8-bit data transmission was supported. If you want to support 32-bit, you must have four 30-line SIMM memory chips. This kind of memory stick is mostly used on 386 or early 486 motherboards. 72-wire SIMM memory sticks can support 32-bit data transmission, and 72-wire SIMM memory sticks are basically provided on 586 motherboards. It should be noted that the data transmission of Pentium processor is 64-bit. At present, 586 motherboards using Intel Triton or Triton II chipset need to use this memory bank in pairs, while 586 motherboards using SIS chipset can use a single 72-wire memory bank due to some special technologies adopted by SIS chips. 8. Dual in-line memory module (DIMM) dual built-in memory model.
DIMM module is the most common memory module at present, that is, two SIMMs. It includes one or more RAM chips on a small integrated circuit board, and some pins on this circuit board can be directly connected to the computer motherboard. DIMM has 168 pins and supports 64-bit data transmission. At present, all processors above Pentium level are 64-bit buses, and the performance of processors can be fully exerted by using this kind of memory.