Introduction to CPU Encapsulation technology

The so-called "CPU packaging technology" is a kind of integrated circuit insulation plastic or ceramic material packaging technology. Taking the CPU as an example, we actually see the size and appearance of the actual CPU core is not the sizes and faces, but the CPU core and other components after the encapsulated product.

CPU encapsulation is a must for the chip and is also crucial. Because the chip must be isolated from the outside, in order to prevent impurities in the air to the chip circuit corrosion caused by electrical performance degradation. On the other hand, the encapsulated chip is also easier to install and transport. Because of the quality of the packaging technology directly affects the performance of the chip itself and the PCB (printed circuit board) connected to the design and manufacture, it is essential. Encapsulation can also be said to install the semiconductor IC chip with the shell, which not only plays the role of placing, fixing, sealing, protecting the chip and enhancing the thermal conductivity, but also the communication chip inside the world and external Circuit bridge-chip contact with wire to the pin of the package shell, These pins also connect to other devices through the wires on the printed circuit board. As a result, encapsulation technology is a critical part of many integrated circuit products.

At present, the CPU is packaged with insulating plastic or ceramic material, can play the role of sealing and improving the electric performance of the chip. As the processor chip's internal frequency is getting higher and stronger, the number of pins is more and more, and the shape of the package is changing constantly. The main factors to consider when packaging:

Chip area and package area ratio to improve package efficiency, as close as possible to 1:1 pin to minimize delay, the distance between pins as far as possible, to ensure non-interference, improve performance based on the requirements of heat dissipation, packaging thinner better

As an important part of the computer, CPU performance directly affects the overall performance of the computer. The final step of the CPU manufacturing process is also the most critical step is the CPU packaging technology, the use of different packaging technology CPU, there is a large gap in performance. Only high-quality packaging technology can produce the perfect CPU product.

Packaging technology for CPU chips:

Dip Package

Dip Packages (Dual In-line package), also known as double-row in-line packaging technology, refers to the use of dual-row plug-in form of integrated circuit chip, the vast majority of small and medium-sized integrated circuits are used in this package, the number of pins generally not more than 100. The dip-encapsulated CPU chip has 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 in the same number of welding holes and geometric arrangement of the circuit board for welding. The dip-encapsulated chip should be particularly careful when plugging from a chip socket to avoid damaging the pins. DIP package structure in the form of: Multilayer ceramic double-row dip, single-layer ceramic double row dip, lead frame dip (including glass ceramic seal, plastic encapsulation structure, ceramic low-melt glass package) and so on.

The DIP package has the following features:

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

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

The first 4004, 8008, 8086, 8088, and other CPUs are available in dip packages, which can be plugged into slots on the motherboard or soldered to the motherboard via two rows of pins.

QFP Package

The Chinese meaning of this technology is called Square Flat packaging Technology (plastic Quad Flat pockage), the technology to achieve a small distance between the CPU chip PIN, the pin is very thin, generally large-scale or VLSI use of this package, the number of pins is generally more than 100. The technology is easy to operate and high in reliability, and its package size is small, parasitic parameters are reduced, which is suitable for high frequency applications. This technology is mainly suitable for SMT surface mount technology to install cabling on the PCB.

　PFP Package

The English language of this technology is all called plastic Flat package, the Chinese meaning is plastic flat-pack. Chips packaged with this technology also have to use SMD technology to weld the chip to the motherboard. SMD-mounted chips do not have to be punched on the motherboard, generally on the motherboard surface has a design of the corresponding pin pads. The chip can be welded to the motherboard by aligning the pins to the corresponding pads. In this way the chip is welded, if not the use of special tools is difficult to disassemble. The technology is basically similar to the above QFP technology, but the appearance of the package shape is different.

　PGA Package

The technology is also called pin grid array packaging technology (Ceramic pin grid Arrau package), the technology encapsulated by the chip inside and outside of a plurality of square-shaped pins, each square-shaped pin along the chip around the interval of a certain distance, according to the number of pins, can be surrounded into 2~5 circle. When installing, insert the chip into a dedicated PGA socket. In order to make the CPU more convenient to install and disassemble, starting with the 486 chip, a ZIF CPU socket has been developed to meet the requirements for the installation and disassembly of the CPU in the PGA package. This technique is commonly used in situations where the insertion and extraction operations are more frequent.

　BGA Package

BGA Technology (Ball grid arrays package) is a spherical grid array packaging technology. The advent of this technology has become the CPU, motherboard south, North Bridge chip, such as high-density, high-performance, multi-pin package the best choice. However, the BGA package occupies a larger area than the substrate. Although the technology has an increased number of I/O pins, the distance between the pins is much larger than the QFP, thus improving the assembly yield. Moreover, the technology adopts the controllable collapse chip method to weld, which can improve its electrothermal performance. In addition, the technology can be assembled by coplanar welding, which greatly improves the reliability of the package, and the package CPU signal transmission delay is small, and the adaptation frequency can be improved very much.

BGA packages have the following features:

Although the 1.I/O pin count increases, the distance between pins is much larger than the QFP package, which improves the yield

2. Although the power consumption of BGA increases, the electric performance can be improved due to the use of controlled collapse chip method welding.

3. Low signal transmission delay, greatly improve the frequency of adaptation

4. Assembly available coplanar welding, reliability greatly improved

The more common form of encapsulation is:

OPGA Package

OPGA (Organic pin grid array, organic pin array). The substrate of this package is made of glass fiber, similar to the material on a printed circuit board. This package can reduce the impedance and package cost. The OPGA package brings the distance between the external capacitor and the processor core closer to better improve core power and filter current clutter. Most AMD ATHLONXP series CPUs Use this type of encapsulation.

MPGA Package

MPGA, a miniature PGA package, is currently used by only a handful of AMD's Athlon 64 and Intel's Xeon (Xeon) series CPUs, and many are high-end products, which are an advanced form of encapsulation.

　CPGA Package

CPGA is often said to be a ceramic package, all called the ceramic PGA. Mainly used in the Thunderbird (Thunderbird) Core and the "Palomino" core of the Athlon processor.

　FC-PGA Package

The FC-PGA package is an abbreviation for the inverted chip pin grid array with pins plugged into the socket. These chips are reversed so that the chip or the processor part of the computer chip is exposed to the top of the processor. By exposing the die, the thermal solution can be used directly on the die, allowing for more efficient chip cooling. In order to improve package performance by isolating power signals and ground signals, the FC-PGA processor has discrete capacitors and resistors at the bottom of the processor's capacitive placement Zone (processor center). The pins on the bottom of the chip are jagged. In addition, the way the pins are arranged allows the processor to plug into the socket only in one way. The FC-PGA package is used for Pentium III and Intel Celeron processors, both of which use 370-pin.

　FC-PGA2 Package

The FC-PGA2 package is similar to the FC-PGA package type, except that the processors also have an integrated heatsink (IHS). The integrated heat sink is installed directly on the processor chip during production. Because IHS has a good thermal contact with the die and provides a larger surface area for better heat dissipation, it significantly increases heat conduction. The FC-PGA2 package is used for Pentium III and Intel Celeron processors (370-pin) and Pentium 4 processors (478-pin).

　Ooi Package

OOI is a shorthand for OLGA. The OLGA represents a grid array of substrates. The OLGA chip also uses a flip chip design, where the processor is attached to the substrate for better signal integrity, more efficient cooling, and lower self-sensing. The OOI has an integrated heat spreader (IHS) that helps the heatsink pass heat to the properly installed fan heatsink. The OOI is used with the Pentium 4 processor, which has 423 pins.

　　PPGA Package

The English language of "PPGA" is called the "Plastic pin grid array" and is an abbreviation for the plastic pin grid array, which has pins inserted into the socket. To improve thermal conductivity, the PPGA uses a nickel-plated copper heatsink at the top of the processor. The pins on the bottom of the chip are jagged. In addition, the way the pins are arranged allows the processor to plug into the socket only in one way.

　S.E.C.C. Encapsulation

"S.E.C.C." Is the "single Edge contact cartridge" abbreviation, is the abbreviation of the single-sided Touch card box. In order to connect to the motherboard, the processor is plugged into a slot. Instead of using pins, it uses "golden finger" contacts, which the processor uses to transmit signals. S.e.c.c. Covered by a metal shell, this shell covers the top of the entire card box assembly. The back of the card box is a thermal material coating that acts as a radiator. S.E.C.C. Internally, most processors have a printed circuit board called a substrate connected to the processor, level two cache, and bus termination circuitry. S.E.C.C. Package for the Intel Pentium II processor with 242 contacts and the Pentium II Xeon and Pentium III processors with 330 contact points.

　S.E.C.C.2 Package

The S.E.C.C.2 package is similar to the S.E.C.C. Package, except that the S.E.C.C.2 uses less protective packaging and does not contain a thermally conductive coating. The S.E.C.C.2 package is used in some later versions of the Pentium II processor and the Pentium III processor (242 contacts).

　S.E.P. Encapsulation

"S.E.P." Is the "single Edge Processor" abbreviation, is a single-sided processor abbreviation. "S.E.P." Encapsulation is similar to "S.E.C.C." or "S.E.C.C.2" package, is also a single-sided insertion into the slot slot, with a gold finger in contact with the socket, but it does not have a fully packaged shell, the backplane circuit from the bottom of the processor is visible. "S.E.P." Encapsulates an Intel Celeron processor that was applied to an earlier 242 golden fingers.

　　PLGA Package

PLGA is an abbreviation for the plastic land grid array, the plastic pad grid array package. Since the use of a small point-and-click interface is not used, the PLGA package is significantly smaller in size, less signal loss, and lower production costs than the previous FC-PGA2 package, which improves the processor's signal strength, increases processor frequency, At the same time, it can improve the yield of processor production and reduce the production cost. Currently, the Intel company Socket 775 Interface CPU uses this package.

CUPGA Package

The CUPGA is an abbreviation for the lidded Ceramic package grid array, which is a covered ceramic grid pattern encapsulation. The biggest difference from ordinary ceramic packages is the addition of a top cover that provides better thermal performance and protects the CPU core from damage. The AMD64 series CPUs are currently packaged in this package.

From: http://tech.yktworld.com/201007/201007242249364308.html

Introduction to CPU Encapsulation technology