The U.S. International Trade Commission (ITC) ruled on Monday that Taiwanese chipset maker Silicon Integrated Systems Corp. (SIS) has infringed on a manufacturing-process patent owned by United Microelectronics Corp. (UMC) and has moved to restrict the import of chips manufactured using the process to the U.S.

However, SIS officials said the ruling would have no affect on users’ ability to find products that incorporate SIS-made products, such as motherboards and graphics cards, in the U.S.

The ruling affects all chips made by SIS using the process in question, including PC chipsets and Xabre graphics chips, said Katherine Huang, a spokeswoman for the company. Chipsets are the main interface between the components of a PC, such as memory, peripherals and the processor.

The ITC ruling is subject to a 60-day presidential review period, during which infringing SIS products can be imported into the U.S. if a bond is posted with the U.S. Customs Service. The bond must cover 100 per cent of the value for each chipset and graphics chip, and 39 per cent of the value of each motherboard or add-in card containing the chips.

If the ITC decision is upheld by the presidential review, infringing SIS products will be banned from importation or sale in the U.S. until 2017.

SIS officials will decide whether to appeal the ruling in U.S. courts based on the result of the presidential review, Huang said.

At the same time, the company has switched to a different manufacturing process for chips, Huang said. Existing SIS products already in the sales channel will not be affected by the ruling, as the ruling is not likely to be implemented before these products are sold and replaced in inventory by chips made using the new process, she said.

In a related action, UMC has also filed a civil suit against SIS, seeking financial damages resulting from patent infringement. That case is pending in U.S. District Court in California, UMC said.