Intro to Three Dimensional Integrated Circuits

Intro to Three Dimensional Integrated Circuits

A three-dimensional integrated circuit (IC) known as a 3DIC is created by vertically stacking various chips or wafers into a single package. The device is connected to other components inside the package using hybrid bonding or through-silicon vias (TSVs).

Why 3DICs?

Allowing more processing in a small space while using less power is essential due to the high demand for data computation. For 2D designs, on the other hand, greater processing translates into a larger chip with more power. Vertical integration or 3D designs have become an effective remedy. A 3DIC design maintains or reduces area while increasing functional density at the same or lower power. The package size for electronic gadgets is reduced as a result. Each die is packaged separately and arranged on a printed circuit board in 2D integrated circuits. Then, conductive wire pathways are used to connect several dies contained in the same packages. In comparison to placing such dies side by side, stacking several dies on top of one another saves room.

Less energy is required for faster data exchange between known good dies when stacks of deaths are closer together. TSVs built into the bottom die are used to transport data between stacked dies. These TSVs are actual, vertically oriented pillars constructed of conductive materials like copper. I/O density is increased by 100x by bonding stacked dies into a single package as opposed to several packages on a PCB. With the most recent technology, the energy per bit transfer can be 30 times lower.

The Benefits of 3DIC

To create the next generation of semiconductor devices in light of Moore's law's slowdown, cramming more functionality onto a single die is not always the ideal strategy. By vertically stacking silicon wafers or dies into a single packed device, 3DICs provide a practical and worthwhile alternative that improves performance, power, and footprint. Benefits include:

  • Reduced Cost and Footprint. Significant cost and yield issues are being brought on by growing design sizes (both in terms of functionality and densities), which are also lengthening development periods. From a cost standpoint, a complex system with several components has a variety of silicon implementation sweet spots. Heterogeneous integration enables the use of the "correct" node for different components of the system rather than placing the entire chip at the most complicated and/or expensive technology node. This limits the use of sophisticated/expensive nodes to only the essential components of the system, while essential components can employ less expensive nodes.
  • Higher Bandwidth. Usually, the first optimization that comes to mind when thinking of huge, complex SoCs is area. The goal of silicon designers is to give the highest performance while integrating the most functionality onto the chip. But there are also the necessary power and thermal envelopes, which are crucial in applications like mobile, wearable augmented reality and IoT. By utilizing 3D structures, designers can keep enhancing the functionality of the product while staying within the bounds of the footprint and height restrictions and, at the same time, reducing silicon costs.
  • Lower Power Consumption. Demand for reduced package sizes has risen as the requirement for lower power consumption soars. In the most advanced technology node, 3DICs can solve with more capacity (gates and memory) than might fit on a single die. Vertical stacking offers interconnects that are quicker, shorter, and use less power.
  • Heterogeneous Integration. Since different manufacturing techniques, technology nodes, and even base technologies can be blended, using several heterogeneous dies offers flexibility. Another method of risk minimization is to reuse existing chips rather than redesigning them for use in a single die. Additionally, it offers the chance to employ reuse to focus on various end-market applications.

Applications for 3DICs

All types of chips that aim for more transistors, less power, or tiny area are perfect candidates for 3DICs. Utilizing 3DIC technology has a variety of benefits for various chip segments, and 3DICs are becoming more and more popular in some of the most demanding semiconductor applications. For mobile devices, the internet of things (IoT), and other applications where space is at a premium, the small footprint is advantageous. For compute-intensive applications like high-performance computing (HPC), data centers, cloud computing, artificial intelligence (AI), and machine learning, the capacity and flexibility are excellent.