3D-IC or the three dimensional integrated circuit is a versatile chip, where more than one layer of electronic active component are fixed into one circuit, both vertically and horizontally too. Currently, this technology is denoted as an emerging innovation, which has a wide range of applications. 

3D Circuit

But, for now only a few sectors have been using it. With time, even this technology will make its mark through its possibilities and competent idea, which may not be found in the other form of the usual 3D circuit. The existence of three dimensional Integrated circuit dates back to 2012, when the very first chip upon a chip circuit was demonstrated. 

This was structured with a multi-core design and had used 130nm process and was built with Tezzazon’s FaStack technology. This was more sort of a two logic die stack, which was better embraced as the prototype of 3D integrated circuit. It earned huge recognition and was soon presented in a better way by the Georgia Institute of Technology. Yet, again several developments kept on happening and finally, the last and the most effective prototype was brought by University of Michigan, which was named as the Centip3De.  

Working of the Three Dimensional Integrated Circuit

The common 3D-IC can work in three possible ways, which are:

  • Wafer on Wafer: In this three dimensional integrated circuit the electronic tools that are used in the making of the circuit are done with the help two semiconductor wafers, that act as a framework for the IC. The best thing is that, the wafers that are used in the making of the circuit can be thinned after aligning the circuit too, which means that the wafer can be thinned either after or before integrating it with the circuit. After that, vertical bonding is made on the wafer with the help of silicon substrate. Monolithic: Here, the connection and the electronic components are fixed with the help of an only one semiconductor wafer, which is then fixed through the 3D- IC. Since, there is only one wafer used in the making of the circuit only one substrate is enough, which means one does not need any type of aligning or bonding in this type of circuit for its working. The only drawback of this type of circuit is temperature. When the circuit faces high temperature then they would possibly form ion-cut which might stop the circuit from proceeding further operations. The reason behind this is; circuits of the silicon substrate work at either cold or moderate temperature.
  • Die on Die:  Just as the name of this type of circuit refers it is done by bonding die using thinning and TSV components. The one prime advantage here is that, before using the die on die circuit each and every component can be checked, which ensures that every die that is present in the stack is working pretty well, as one die can ultimately destroy the entire circuit.
  • Die on Wafer: This is a peculiar combination of Die with wafers semiconductors. Here, the electronic components are established with two semiconductors one is wafer and the other dice. This, circuit almost holds the same technique that can be explored in the wafer on wafer IC.

Die on Wafer

Advantages of Three Dimensional Integrated Circuit

  • The common materials that are used in the making of 3D-IC are cost effective.
  • The electrical components are easy to access too.
  • It’s a tiny device that holds lot of power
  • Every circuit is designed with a safety electrical component to make sure that any malfunction does not lead to lethal hazards of the device or the circuit.
  • Everything is interconnected in the circuit, this increases the wires used in the circuit and the less the wire the lesser will be the complications in creating the circuit.
  • Closer look to the design portrays that its actually quite simple to understand
  • The bandwidth is perfect and it elevates the working of this IC too.

Common Challenges Faced with Three Dimensional Circuit

The one common and the most miserable challenge that was faced by the makers of 3D-IC is high temperature. It was even noted earlier, that the circuit goes all crazy when the temperature drops up, this is indeed a great challenge, and the developers have constricted their attention towards it, so that the thermal proximity can be overcome.

Another challenge that is faced by the developers is the complexity in the designing of the three dimensional circuits; since they are the tools of the next generation, designing them even required perfect tools like proper advanced CAD tools so that the process can be done in a sophisticated manner. Final and the last challenge are to test each and every component that is used in the making of the integrated circuit.