How chips are made
Chips are made by building electronic circuits onto a thin disc of ultra-pure silicon, called a wafer, through hundreds of repeated steps of depositing material, printing patterns with light, and etching material away, all inside a cleanroom. Once the wafer is finished it is cut into individual chips, each packaged and tested before shipping. The Tata Electronics and PSMC fab at Dholera is being built to run this full front-end process at a target of up to 50,000 wafers per month on 300 mm wafers.
It starts with sand and silicon
The raw ingredient of a chip is silicon, refined from ordinary sand into an extraordinarily pure form. The silicon is melted and grown into a single large crystal, a cylindrical ingot, using a process that pulls a rotating seed crystal slowly out of the molten silicon so the whole ingot forms as one continuous crystal lattice. That single-crystal structure is essential, because defects in the lattice would disrupt the delicate electrical behaviour the chip depends on. The ingot is then sliced into thin, round wafers, which are polished until they are almost perfectly flat and mirror smooth. The Dholera fab uses 300 mm wafers, the industry standard for high-volume production, meaning each wafer is 300 millimetres across. A larger wafer carries more chips, which spreads the cost of processing across more finished parts. These blank wafers are the canvas on which the entire circuit will be built.
Building layers with deposition and doping
A chip is not a flat drawing but a stack of many layers, so making one is a repeated cycle of adding material and shaping it. Deposition lays down ultra-thin films across the whole wafer, films that may be conducting, insulating or semiconducting depending on the layer's job. Some films are grown chemically, others are sputtered on from a solid source, and the thickness is controlled to within a few atoms. Doping is the step that gives silicon its electrical personality. By firing precise amounts of specific atoms into chosen regions of the wafer, engineers create the zones that carry current one way or another, forming the two halves of a transistor. Heat treatments then move and settle those atoms into place. This is where the raw semiconductor becomes an active device rather than just a slab of silicon. Each layer must line up with the ones below it to a tiny fraction of the feature size, which is why alignment and repeatability are obsessions in a fab.
Printing the circuit with lithography
Lithography is the step that decides where everything goes, and it is the defining technology of chip making. The wafer is coated with a light-sensitive chemical called photoresist. A pattern for the current layer, held on a mask, is then projected onto the wafer using light shone through precise optics, exposing the resist wherever the pattern allows light through. The exposed or unexposed resist is developed away, leaving a stencil on the wafer surface. That stencil defines where the next etch or implant will act. The finer the light and optics, the smaller the features that can be printed, which is what process nodes measure. Because a chip has many layers, this print-and-develop cycle is repeated for every layer, each aligned to the last. Tata Electronics signed a lithography partnership with ASML, the global leader in lithography systems, reported around 17 May 2026, since lithography tools are the most complex and costly equipment in any fab.
Etching, cleaning and polishing
Once a pattern is printed in photoresist, etching transfers it into the material below by removing the exposed areas, either with reactive gases in a plasma or with liquid chemicals. What remains is the actual physical structure of that layer, whether a wire, a gate or an insulating gap. After etching, the leftover resist is stripped and the wafer is cleaned, because any residue could interfere with the next step. Between layers the wafer is polished flat using chemical mechanical planarisation, a process that grinds and chemically smooths the surface so that the next layer can be built on a level foundation. Without this flattening, the stack of layers would become too uneven to print accurately. These steps of etch, clean and polish are woven through the whole flow, repeated dozens of times as the transistors are formed first and then the metal wiring that connects millions or billions of them into a working circuit is built up above.
Testing on the wafer, then cutting it up
When all the layers are complete, the wafer holds a grid of finished chips, but the work is not done. Each chip is tested while still on the wafer, using fine probes that touch its contact pads and run electrical checks. Chips that fail are marked so they can be discarded later. This early testing saves money, because there is no point packaging a chip that is already known to be faulty. The share of good chips on a wafer is called yield, and improving yield is one of the central challenges of running a fab, especially in the early ramp. After wafer testing, the wafer is diced, meaning it is precisely cut into the individual chips. From here the chips leave the fab and move to the back-end assembly and test stage. The wafer processing described so far is the front end of line, the part the Dholera fab is built to perform.
Packaging and final test
A bare chip is fragile and its connections are far too small to attach to a circuit board directly, so each chip is placed into a package. Packaging encases the chip in a protective body and provides larger, robust electrical connections to the outside world, whether pins, balls or pads. This back-end work is usually done in a separate facility known as an OSAT, for outsourced semiconductor assembly and test. After packaging, every chip is tested again under realistic conditions, sometimes across a range of temperatures and voltages, to confirm it performs to specification before it ships. Only chips that pass reach customers. A complete chip ecosystem needs both fabs and this back-end capacity, which is why Dholera's strategy pairs the large Tata fab with a wider cluster, including two additional semiconductor units cleared on 5 May 2026, one in Dholera and one in Surat, worth over Rs 3,900 cr combined and more than 2,200 skilled jobs.
FAQ
What is a chip made from?
A chip is built on a wafer of ultra-pure silicon, refined from sand and grown as a single crystal, then sliced and polished. Circuits are formed on the silicon by adding thin films of conducting, insulating and semiconducting materials and by doping regions with specific atoms. The Dholera fab uses 300 mm wafers, the high-volume standard.
How long does it take to make a chip?
Wafer processing alone can take several weeks, because a chip is built from many layers and each layer requires its own cycle of deposition, lithography, etching, cleaning and inspection. Advanced chips can involve several hundred process steps. After the wafer is finished, dicing, packaging and final testing add more time before a chip ships.
What is the most important step in making a chip?
Lithography is often called the defining step, because it decides where every feature goes and how small those features can be. It prints the circuit pattern onto light-sensitive photoresist on the wafer. Tata Electronics signed a lithography partnership with ASML, a global leader in the field, reported around 17 May 2026 for the Dholera fab.
What is wafer yield?
Yield is the share of good, working chips on a finished wafer. Not every chip passes, because tiny defects can spoil some of them, so improving yield is a central goal of running a fab, especially during the early ramp. Chips are tested on the wafer with fine probes before the wafer is cut up.
Does the Dholera fab handle the whole process?
The Dholera fab performs the front end of line, the wafer processing that creates the transistors and wiring. The back-end work of cutting the wafer, packaging each chip and final testing is done in assembly and test facilities. Dholera's cluster strategy pairs the large Tata fab with additional units to build a fuller ecosystem.