Microwind VLSI Tutorial 8 NAND Gate Layout
Channel: Explorer
Date: 30/08/2020

This video was created for Sonargaon University. Especially for the students of Electrical and Electronic Engineering dept. and undergraduate students enrolled in VLSI course or VLSI LAB course.



Very large-scale integration (VLSI) is the process of creating an integrated circuit (IC) by combining millions of MOS transistors onto a single chip. VLSI began in the 1970s when MOS integrated circuit chips were widely adopted, enabling complex semiconductor and telecommunication technologies to be developed. The microprocessor and memory chips are VLSI devices. Before the introduction of VLSI technology, most ICs had a limited set of functions they could perform. An electronic circuit might consist of a CPU, ROM, RAM and other glue logic. VLSI lets IC designers add all of these into one chip.


Integrated circuit layout, also known IC layout, IC mask layout, or mask design, is the representation of an integrated circuit in terms of planar geometric shapes that correspond to the patterns of metal, oxide, or semiconductor layers that make up the components of the integrated circuit. Originally the overall process was called tape out as historically early ICs used graphical black crepe tape on mylar media for photo imaging (erroneously believed to reference magnetic data--the photo process greatly predated magnetic media).

When using a standard process—where the interaction of the many chemical, thermal, and photographic variables is known and carefully controlled—the behaviour of the final integrated circuit depends largely on the positions and interconnections of the geometric shapes. Using a computer-aided layout tool, the layout engineer—or layout technician—places and connects all of the components that make up the chip such that they meet certain criteria—typically: performance, size, density, and manufacturability. This practice is often subdivided between two primary layout disciplines: Analog and digital.

The generated layout must pass a series of checks in a process known as physical verification. The most common checks in this verification process are

design rule checking (DRC),
layout versus schematic (LVS),
parasitic extraction,
antenna rule checking, and
electrical rule checking (ERC).