TAIPEI, May 16 (Reuters) - Taiwanese silicon wafer

manufacturer GlobalWafers said on Friday it would

invest an additional $4 billion in the United States to meet

growing customer demand there, as it officially opened its new

$3.5 billion wafer facility in Texas.

"Our U.S. customers appear to have a very strong demand for

U.S.-based production capacity," Doris Hsu, Chairperson of

GlobalWafers, a TSMC supplier, told reporters.

"Although tariffs (on semiconductors) have not been

finalized...(U.S.) customers are hoping to secure local supply to

reduce the potential uncertainties that tariffs may bring."

The plant, GlobalWafers' most advanced fully integrated

300mm (12 inch) silicon wafer facility, is the first of its kind

built in the U.S. in more than two decades and is currently the

only advanced wafer manufacturing site in the country.

Silicon wafers are critical components in chip manufacturing

and larger wafers are widely used in advanced chip production as

they allow for more chips to be produced per each wafer,

increasing cost savings.

At the opening ceremony held in Sherman, Texas, on Thursday,

the company said it intends to add two more phases to the site

to boost production capacity. It currently has one phase

completed for production and a second phase is planned for

construction in the 142-acre campus that is designed to

accommodate up to six phases.

Hsu said there is no set timeline for the additional two

phases, but several conditions must be met before moving

forward.

"Phases one and two must be profitable, and we need to

secure customers... who show strong interest in local production

and are willing to sign long-term contracts," Hsu said.

"We also need reasonable pricing, prepayments, and

government support. If these conditions are met, we'll move

ahead."

The plant is part of the Biden administration-era CHIPS for

America program and the company is set to receive $406 million

in U.S. government grants for its projects in Texas and

Missouri.

Hsu said it has not yet received the U.S. funding but has

reached key milestones and submitted the required documentation.

Hsu expected the funds to be disbursed in the first half of this

year.

Reuters reported in February the Trump administration is

seeking to renegotiate U.S. CHIPS and Science Act awards and has

signalled delays to some upcoming semiconductor disbursements.

U.S. President Donald Trump has repeatedly criticized the

CHIPS Act and said in March U.S. lawmakers should get rid of it

and instead use the proceeds to pay debt.

(Reporting by Wen-Yee Lee; Editing by Christopher Cushing,

Miyoung Kim and Lincoln Feast.)