TAIPEI, Sept 5 (Reuters) - Taiwan's GlobalWafers Co Ltd has no definite figure for subsidies yet it may seek under a U.S. programme to boost chip production nor a timetable for negotiations, the company's chairwoman and chief executive Doris Hsu said on Tuesday.

The company said last year it would build a $5 billion plant in Texas to make 300-millimetre silicon wafers used in semiconductors, switching from a defunct plan to invest in Germany.

The United States has been encouraging foreign tech firms to manufacture in the country, and the government has welcomed the investment by GlobalWafers.

Last year, U.S. President Joe Biden signed into law the Chips and Science Act, which authorised about $52 billion in government subsidies for U.S. semiconductor production and research, and an investment tax credit for chip plants estimated to be worth $24 billion.

Hsu told reporters in Taipei said the subsidies were still in the "pre-application" phase, and each company applying for them would have its own timetable.

"We're not yet at the phase of discussions or negotiations for the final amount, or a definite time. We still don't know," she said, adding the figure that could be applied for was also undecided.

GlobalWafers' investment will be the first silicon wafer facility to be built in the United States in more than two decades, according to the U.S. Commerce Department.

Taiwan Semiconductor Manufacturing Co Ltd (TSMC), a major Apple Inc

GlobalWafers, also a major TSMC supplier, is expanding existing sites in Italy and Denmark, and those plans are well on track, Hsu said. (Reporting by Ben Blanchard Editing by Tomasz Janowski)