Bojie chip dicing machine: the characteristics of the motherboard control chipset using BGA packaging technology
At present, motherboard control chipsets mostly use this kind of packaging technology, and the materials are mostly ceramics. The memory packaged with BGA technology can increase the memory capacity by two to three times while maintaining the same volume. Compared with TSOP, BGA has smaller volume, better heat dissipation performance and electrical performance.
The characteristics of two BGA packaging technologies
BGA package memory: The I/O terminals of the BGA package are distributed under the package in the form of circular or columnar solder joints in an array. The advantage of BGA technology is that although the number of I/O pins has increased, the pin spacing has not decreased. increased, thereby improving assembly yield; although its power consumption increases, BGA can be welded with a controlled collapse chip method, which can improve its electrothermal performance; thickness and weight are reduced compared with previous packaging technologies; parasitic The parameters are reduced, the signal transmission delay is small, and the frequency of use is greatly increased; the assembly can be coplanar welding, and the reliability is high.
TinyBGA package memory: The volume of memory products using TinyBGA package technology is only 1/3 of that of TSOP package under the same capacity. The pins of TSOP package memory are drawn from the periphery of the chip, while the pins of TinyBGA are drawn from the center of the chip. This method effectively shortens the transmission distance of the signal, and the length of the signal transmission line is only 1/4 of the traditional TSOP technology, so the attenuation of the signal is also reduced. This not only greatly improves the anti-interference and anti-noise performance of the chip, but also improves the electrical performance.
The substrate or intermediate layer is a very important part of the BGA package. In addition to being used for interconnection wiring, it can also be used for impedance control and integration of inductors/resistors/capacitors. Therefore, the substrate material is required to have a high glass transition temperature rS (about 175~230°C), high dimensional stability and low moisture absorption, as well as good electrical performance and high reliability. There is also a need for high adhesion between the metal film, the insulating layer and the substrate medium.
Three major BGA packaging processes and processes
1. Packaging process flow of wire bonded PBGA
1. Preparation of PBGA substrate
Laminate very thin (12~18μm thick) copper foil on both sides of the BT resin/glass core board, and then perform drilling and through-hole metallization. Use conventional PCB processing technology to make graphics on both sides of the substrate, such as conduction bands, electrodes, and land arrays for installing solder balls. A solder mask is then added and patterned to expose the electrodes and pads. In order to improve production efficiency, a substrate usually contains multiple PBG substrates.
2. Packaging process
Wafer thinning→wafer cutting→chip bonding→plasma cleaning→wire bonding→plasma cleaning→molding packaging→assembling solder balls→reflow soldering→surface marking→separation→final inspection→test bucket packaging.
2. FC-CBGA packaging process
1. Ceramic substrate
The substrate of FC-CBGA is a multilayer ceramic substrate, and its production is quite difficult. Because the wiring density of the substrate is high, the spacing is narrow, there are many through holes, and the coplanarity requirements of the substrate are high. Its main process is: first co-fire the multilayer ceramic sheet at high temperature into a multilayer ceramic metallized substrate, then make multilayer metal wiring on the substrate, and then perform electroplating and so on. In the assembly of CBGA, the CTE mismatch between the substrate, the chip and the PCB board is the main factor causing the failure of CBGA products. To improve this situation, in addition to the CCGA structure, another ceramic substrate - HITCE ceramic substrate can also be used.
2. Packaging process
Wafer bump preparation->wafer cutting->chip flip-chip and reflow soldering->underfill thermal grease, sealing solder distribution->capping->assembly solder balls->reflow soldering->marking->separation ->Final Inspection ->Test ->Packing.
3. Packaging process flow of wire bonded TBGA
1. TBGA carrier tape
The carrier tape of TBGA is usually made of polyimide material. During production, copper cladding is first carried out on both sides of the carrier tape, then nickel and gold plating, and then through-holes and through-hole metallization and graphics are produced. Because in this wire-bonded TBGA, the package heat sink is the reinforcement of the package and the core cavity base of the package, so the carrier tape must be bonded to the heat sink with a pressure-sensitive adhesive before packaging.
2. Packaging process
Wafer thinning→wafer cutting→chip bonding→cleaning→wire bonding→plasma cleaning→liquid sealant potting→assembling solder balls→reflow soldering→surface marking→separation→final inspection→testing→packaging.
The main reason for the popularity of BGA packaging is that it has obvious advantages, and its unique advantages in packaging density, electrical performance and cost allow it to replace traditional packaging methods. As time goes by, BGA packaging will have more and more improvements, and the cost performance will be further improved. BGA packaging has flexibility and excellent performance, and has a bright future.
