ATMP & OSAT

Think of a chip's life in two stages, the way a diamond moves through the world. First, a rough stone is mined and cut into its raw crystalline form, a slow, capital intensive, high precision process. Then it is polished, set into a ring, tested for clarity and shipped to a store. Fabrication is the mining and cutting. ATMP, short for Assembly, Testing, Marking and Packaging, and OSAT, Outsourced Semiconductor Assembly and Test, are the polishing, setting and shipping. Industry uses the two terms almost interchangeably to describe the same back end of chip manufacturing.

A finished silicon wafer coming out of a fabrication plant is not yet a usable chip. It has to be sliced into individual dies, tested for defects, assembled into a protective package, and marked with identifying codes before it can go into a phone, a car or a server. This back end work is less exotic than building a fab from scratch, needs a fraction of the capital, and can be stood up in a few years rather than a decade. That combination is exactly why India's semiconductor push chose to build here first.

Micron's ATMP facility in Sanand, Gujarat, a 2.75 billion dollar investment, was inaugurated in February 2026 and is now producing DRAM and NAND flash packages for mobile devices, data centres and automotive use. CG Power's OSAT facility, also in Sanand, brought its first pilot line online in August 2025 with capacity to handle half a million chip units a day, with a second phase designed to scale to 14.5 million units a day. Tata Electronics built a parallel ATMP unit, branded Tata Semiconductor Assembly and Test, in Jagiroad, Assam, alongside its larger fabrication plant under construction in Dholera, Gujarat.

Under the government's semiconductor incentive framework, ATMP and OSAT projects qualify for fiscal support of up to 50 percent of project cost, a deliberately generous number designed to compensate for the fact that India is starting from close to zero in a business where Taiwan, South Korea and China have decades of head start. Gujarat's Sanand cluster in particular has emerged as India's de facto ATMP hub, hosting three separate anchor projects within a few kilometres of each other.

When the news talks about India making chips, it is worth checking whether the plant in question is a fab, cutting raw silicon into circuits, or an ATMP or OSAT facility, finishing chips that were often fabricated elsewhere. India's first wave of investment has overwhelmingly been the second kind, a sensible place to build real manufacturing muscle before attempting the far harder, far more capital intensive business of fabrication itself.