Personal tools

Stages of Semiconductor Production

Chip Fabrication Steps_050723A
[Chip Fabrication Steps - Paul von Bitsand Chips]


- Overview

Semiconductors are made from a variety of raw materials, including: Silicon, Germanium, Gallium arsenide, Indium phosphide. 

Semiconductors are made using a multiple-step photolithographic and physio-chemical process. The process includes: Thermal oxidation, Thin-film deposition, Ion-implantation, Etching, etc.

One of the most important machine tools used in semiconductor manufacturing is the lithography machine. This machine prints circuit patterns onto silicon wafers. The circuit patterns are created using a mask, which is a template that contains the desired pattern.

The most common semiconductor device in the world is the MOSFET (metal–oxide–semiconductor field-effect transistor), also called the MOS transistor. As of 2013, billions of MOS transistors are manufactured every day.


- The Semiconductor Production Process

The semiconductor production process is a complex series of steps that transform raw materials into integrated circuits. The process involves many critical stages, including:
Wafer preparation, Photolithography, Etching, Doping, Metallization, Passivation, Packaging, Testing. 

The process begins with a silicon wafer. The wafers are sliced from a salami-shaped bar of 99.99% pure silicon (known as an "ingot") and polished to extreme smoothness.

The process involves hundreds of steps and can take up to four months from design to mass production. Some of the steps in the process include: 

  • Thermal oxidation
  • Thin-film deposition
  • Ion-implantation
  • Lithography
  • Chemical mechanical planarization
  • Diffusion
  • Cleaning
  • Film deposition
  • Post-deposition cleaning
  • Resist coating
  • Exposure
  • Development
  • Implantation of impurities


- Semiconductor Device Fabrication

Semiconductor device fabrication is the process used to manufacture semiconductor devices, typically the metal–oxide–semiconductor (MOS) devices used in the integrated circuit (IC) chips that are present in everyday electrical and electronic devices. 

It is a multiple-step sequence of photolithographic and chemical processing steps (such as surface passivation, thermal oxidation, planar diffusion and junction isolation) during which electronic circuits are gradually created on a wafer made of pure semiconducting material. Silicon is almost always used, but various compound semiconductors are used for specialized applications. 

The entire manufacturing process, from start to packaged chips ready for shipment, takes six to eight weeks and is performed in highly specialized semiconductor fabrication plants, also called foundries or fabs. All fabrication takes place inside a clean room, which is the central part of a fab. 

In more advanced semiconductor devices, such as modern 14/10/7 nm nodes, fabrication can take up to 15 weeks, with 11–13 weeks being the industry average. Production in advanced fabrication facilities is completely automated and carried out in a hermetically sealed nitrogen environment to improve yield (the percent of microchips that function correctly in a wafer), with automated material handling systems taking care of the transport of wafers from machine to machine. 

Wafers are transported inside FOUPs, special sealed plastic boxes. All machinery and FOUPs contain an internal nitrogen atmosphere. The air inside the machinery and FOUPs is usually kept cleaner than the surrounding air in the cleanroom. This internal atmosphere is known as a mini-environment. Fabrication plants need large amounts of liquid nitrogen to maintain the atmosphere inside production machinery and FOUPs, which is constantly purged with nitrogen.


- Processing Steps for Building Electronic Devices

This is a list of processing techniques that are employed numerous times throughout the construction of a modern electronic device; this list does not necessarily imply a specific order. Equipment for carrying out these processes is made by a handful of companies. All equipment needs to be tested before a semiconductor fabrication plant is started.  

  • Step 1: Research: Pre-competitive basic research is essential to the semiconductor industry and the first step in the semiconductor production process. 
  • Step 2: Design: Engineers use sophicated equipment to design semiconductors, similar to architects design buildings.
  • Step 3: Raw Materials: Many semiconductors start out as sand, which contains a large amount of silicon, but other pure materials can also be used.
  • Step 4: Ingot: The sand is purified and melted into solid cylinders called ingots, weighing up to 200+ IBs.
  • Step 5: Blank Wafer: The ingot is then sliced into very thin (1 mm) silicon discs and polished into a flawless finish.
  • Step 6: Finish Wafer: Next, wafers are printed with highly intricate circuit designs that will later become individual chips.
  • Step 7: Cut Wafer: The silicon wafer containing finished semiconductors, sometimes as many as 70,000 per wafer, is then cut up into tiny individual semiconductors called dies.
  • Step 8: Packaged Chip: These dies are then packaged into finished semiconductors, which can be placed into devices.
  • Step 9: Chip on Circuit Board: Finished semiconductors are embedded in countless electronics devices, from computers and smar phones to highly advanced medical equipment and supercomputers.



[More to come ...]

Document Actions