Nine hundred workers at Seagate in Limavady have been given details of their redundancy packages.
Seagate has been in the area for 10 years
It understood they have each been offered six weeks pay for every year they have worked at the plant, but only if they stay until July.
This means the average redundancy package will work out at about £20,000.
If they leave their jobs before then, they will get four weeks pay for every year they have been employed at the factory.
Willie Haywood, from Seagate's Employees' forum, said consultations with management would continue to see if any jobs could possibly be saved.
The plant is closing in the second half of next year.
Staff at the factory were told on Monday they were losing their jobs.
Seagate has received £12m from Invest Northern Ireland and its predecessor IDB, since 2001.
The company's John Spangler said they did everything they could to keep the Limavady factory going.
"We wanted to make a go of it, we've investigated numerous ways to keep that plant open and we want to keep it open for the next nine months," he said.
"Hopefully we can come up with some ideas that still might save it but right now it doesn't look viable."
Employment Minister Sir Reg Empey has said the NI Executive would do all it could to help workers find new jobs.
"I am making arrangements for my department to provide assistance through our district and local offices and local employer contact team," he said.
The American company has had a base in Limavady for the last decade.
However, it has a plant in Malaysia which is due to start operations in the new year.
It will make the computer components currently being made in Limavady.