Micron's Sanand chip plant enters crucial cleanroom validation stage

The first phase of Micron's ambitious plant at Sanand, Gujarat, has progressed towards cleanroom validation, people in the know told ET. A cleanroom is a highly controlled environment designed to minimise the presence of airborne particles like dust, bacteria and chemical vapours that could compromise sensitive processes or products.

"What Micron is doing is that they are trying to make Phase 1 of the main facility operational by the second half of this year," one of the people said. "The certification is being done in order to enable that timeline."

With a planned cleanroom space of half a million square feet in its first phase, this will be an assembly, testing, marking and packaging (ATMP) unit for Micron.

The US-based memory chip maker plans to invest up to $825 million over the two phases of the project. The combined investment by Micron and government entities will be up to $2.75 billion.

In a June 22, 2023 news release, Micron had said that the Phase 1 would start to become operational in late 2024 and that the company would ramp capacity gradually in line with global demand trends. Micron had said at the time that it expects Phase 2, which would include construction of a facility similar in scale to Phase 1, to start towards the second half of the decade.

While initial timelines have seen some adjustments, with construction contractor Tata Projects saying that the handover of the facility is now expected to be handed over by December 2025, the commencement of cleanroom validation is seen as a significant step towards the plant becoming operational.

Queries sent to Micron remained unanswered as of press time Tuesday.

"Cleanroom validation is a cornerstone in semiconductor manufacturing because it ensures the production environment meets the extremely stringent conditions required for the fabrication of delicate microelectronic devices," said Krishna Moorthy, a semiconductor industry technology veteran and former CEO of the India Electronics and Semiconductor Association. "In this industry, even a single contaminant — whether a microscopic dust particle or a stray chemical — can disrupt processes like photolithography, etching and deposition, leading to defects and costly yield losses," he told ET.


Validation systematically certifies that environmental parameters (particle counts, temperature, humidity, airflow and static control among others) adhere to strict specifications, he said.

But beyond the immediate risk of contamination, cleanroom validation plays a pivotal role in overall process control and quality assurance.

"Regular and rigorous validation helps identify any deviations in the cleanroom’s performance over time, facilitating early intervention before production is compromised," Moorthy said. "This ongoing process not only mitigates risks associated with equipment downtime or process deviations but also assists in regulatory compliance and customer assurance. Moreover, as semiconductor devices continue to shrink in size, the margin for error becomes ever smaller."

After a cleanroom is validated in a semiconductor manufacturing facility, it essentially transitions from the commissioning and qualification phase into full-fledged production.

"The post-cleanroom validation phase for an assembly, test, marking, and packaging facility shares some common fundamentals with those in front-end wafer fabrication—but there are notable differences tailored to the specific back-end operations," Moorthy said. "In an ATMP facility, while the cleanroom environment is crucial, the focus shifts more toward ensuring that the subsequent processes—such as chip bonding (via wire or flip-chip techniques), electrical testing, thermal cycling, reliability checks, and final encapsulation—are faithfully executed."

The tools and machinery for assembly, test, marking and packaging are installed, calibrated and integrated into the validated cleanroom. However, unlike the front-end processes, ATMP operations emphasise functional and reliability attributes of the packaged device. Here, process qualification includes not just verifying that the controlled environment is maintained, but also that all assembly and testing techniques meet stringent product and reliability criteria.

"After cleanroom validation, the ATMP facility incorporates additional layers of process validation," Moorthy said. "This might include burn-in testing, end-use simulation and comprehensive inspection protocols to certify that the completed packages consistently reach the design specifications required for market or application standards."