Chapter 28, Problem 1RQ

Define the terms wafer, chip, die, device, integrated circuit, line width, registration, surface mount, accelerated-life testing, and yield.

To determine

Define the terms wafer, chip, die, device, integrated circuit,line width, registration, surface mount, accelerated-lifetesting, and yield.

Explanation of Solution

Wafer fabrication:

Wafer fabrication can be used to make completely electrical or photonic circuits by repeating chronological processes. Some of the examples of components that are produced using this technique are radio frequency (RF) amplifiers, LEDs, optical computer components, and CPUs for computers. This technique is responsible for making structures that are required for electrical activity.

Chip:

A chip is a semiconducting material of small dimensions that is used as a base to fabricate a circuit. Chips that are manufactured now have varied dimensions ranging from 0.5mm×0.5mm to 50mm×50 mm in rare cases. With newer technologies, it is possible to create chips with density of around 10 million devices per chip and this is known as very large scale integration (VLSI).

Die:

In the perspective of integrated circuits, a die is a block that is made using semiconducting material and the functional circuit is fabricated over it. Generally, integrated circuits are produced using processes like photolithography. It is a mass production setup where they are made on a single wafer of semiconductor like electronic-grade silicon (EGS) or GaAa.

Device fabrication:

Device fabrication is used to manufacture integrated circuits used in electrical and electronic devices. There are several steps involved that need to be carried out in a chronological order. These steps include photolithography and other chemical processes. It uses a pure semiconducting material like silicon as the wafer over which the whole electronic circuit is fabricated. Other semiconductor compounds are also used depending on the applications of the device.

Integrated circuit (IC):

Integrated circuit is a wafer that is made from semiconductor material and several other components like resistors, capacitors and transistors are fabricated over it. It is also known as a chip or a microchip in general terms. It can be used as an amplifier, oscillator, timer, counter, computer memory, or even a microprocessor. Based on its desired application, an IC can be categorized into either a linear (analog) IC or a digital IC.

Line width:

Line width is the tiniest feature that can be imprinted on the surface of a silicon during lithography. It is also called as the critical dimension (CD). With the increasing circuit density, there has been decrease in the size of devices. They have become very small and 32nm is the feasible critical dimension that can be made commercially. Work has been going on to achieve a CD of 16nm or smaller.

Registration:

In the registration step, the reticle should be placed properly according to the previous layer on the wafer. After it is properly aligned, it can be placed under UV radiation. After exposure to UV, it is developed and the exposed photoresist is removed from the wafer.

Surface-mount technology (SMT):

Surface mount technology is a technique to create electronic circuits. In this technique, a PCB (printed circuit board) is taken and the components are directly mounted or placed over it. This produces a surface mount device (SMD). This technology has replaced the other technology used for fitting components which is the through-hole technology. In this technology, the components are fitted into the holes of the board using wire leads. In a single board, both these technologies can be used depending on the components. For some components, SMT is not possible like in case of large transformers and heat-sink power semiconductors.

Accelerated life testing:

Accelerated life testing is used to test a component to identify its faults and potential failure modes in small time duration. The component is tested against extreme conditions of parameters like stress, strain, temperatures, voltage, vibration rate, pressure etc. The results of these tests can be analyzed by engineers and they can predict the service life of a product. They can also give predictions about the required maintenance intervals for the same.

Yield:

Some of the important points to consider in the process of microelectronic fabrication are Yield Models, Defect Size Distribution, Defectivity, Redundant Vias, Yield Models, Poisson Model, Seed’s Model, Murphy Model, and Gamma Model.