Old in the days, computers were huge in size, hence, not that powerful and relatively slow when compared to computers nowadays. A computer is a complex electrical integrated circuit connects multiple of electrical components together. These components could be summarized in the following; transistors, resistors, capacitors and diodes. Therefore, when it comes to high tech computers, revolutionary quality is a serious matter. One of the computer quality standards for example is the speed at which a computer carries out calculations, this speed is determined by transistors speed. The faster the transistor the better the computer.
When computers were invented, electronics manufacturing was very expensive because of the assembly costs, large components costs, and manufacturing costs. However, computers nowadays are cheaper because they are smaller as well as their manufacturing and assembly is semiautomated. The world is producing massive volumes of small electronic products and all are being implemented in the market, which dropped the prices big time. The previous is a result of the very large-scale integration and mass production of microprocessors, that’s when formation of CHIPS started.
Electronic industry is heading towards fully automated production lines. However, even the fact that it is still not fully automated, the need of the market requires that transistors on any integrated circuit board to be doubled every 18 months according to Moor’s law. This law has been adopted in the manufacturing industry a lot, since it pays back the economy. For example, if the performance of computers is not doubling every 18 months, then people will not be buying new computers.
Packaging on the microelectronic level is the connection between Integrated Circuit and an Electronic system, which also comprises all the technologies between them.
I.Szendiuch, Radiengineering. 20(1), 214 (2011)
Therefore, while the need of the industry is all about smaller electronic devices in a limited time window, innovative technologies are being adopted towards manufacturing automation.
1- 3D Assembly (Stacking) of Chips
Attaching number of transistors and combine them in a single chip increases the performance and reduce the cost. Manufacturing an integrated circuit through vertically stacking chips, silicon wafers and dies and interconnect them using through-silicon vias (TSVs). A 3D assembly of chips is generally referred to as a chip comprised of two or more active semiconductor devices. The whole purpose of the previous is that a chip acts as a single component. 3D assembly’s major purpose is to improve the electrical performance power saving, and reduction of used space 1. 3D assembly is implemented in so many applications, such as; smart phones, laptops, medical devices, and military aircrafts.
Here the detector assembly is basically attached on a circuit board with ball grid array joint.
3D Packaging has introduced a new concept in the semiconductors market to sustain Moore’s Law with minimal cost. It has been widely adopted in the market; e.g Apple A7 and iPhone 5S with a POP configured package. 4 Current 3D packaging focuses on processing of wafers and TSV fabrications. However, 3D assembly will become more complicated, unreliable, and less productive, if this rapid exponential increase of the transistors keeps growing. Due to that, electronic assembly will have few billions of nano particle in the future, thus there will be constraints on reducing the chip size. Instead the number of transistors on the board could be increased while the chip size remains unchanged. The previous will definitely increase productivity.
There are number of approaches that are being used in 3D packaging:
Die-to-Die; components are built on different dies, and dies are bonded together.
Die-to-Wafer; components are built on wafers, one of the wafers is on a die, then bond them together.
Wafer-to-Wafer; build components on multiple wafers, then bond these wafers together 3.