TSK has lost in its patent lawsuit that saw its patents related to silicon carbide (SiC) ring production invalidated by a South Korean court.
DS Techno had earlier filed filed the lawsuit against the company asking the patent court to invalidate the patents.
The latest court decision was made in the appeals court on August 2. TSK had also lost at the district court level back in September.
TSK can appeal and take the case to the Supreme Court but people familiar with the matter said the decision will likely remain the same.
TSK had dominated the global SiC ring market thanks to the patents but its recent lost means rivals such as DS Techno, KNJ and Hana Materials to enter the market.
TSK first filed its lawsuit against DS Techno back in November 2019. DS Techno retaliated with its own counter suit to have the patents invalidated.
SiC rings are used to hold the wafer in place during semiconductor production.
SiC is more durable than previous quartz or silicon, allowing the rings to be used longer.
TSK is thought to have held over 80% market share in SiC rings. The business had accounted for 83.7% of its sales during the second quarter. TSK also recorded an operating margin rate of 39.09% during the quarter, showing that the business is very profitable.
TSK uses the raw material provided by Japanese subsidiary Tokai Carbon for the SiC rings.
The company had claimed DS Techno violated two of its patents. One of them, 1866869 has to do with SiC material and material characteristics.
The other patent, 1914289, has to do with varying transmittance multi-layer SiC semiconductor production component manufacturing method. This patent was invalidated in April by the local panel board.
The board however found that DS Techno infringed on patent 1866869, and the company immediately appealed.
The appeals court invalidated this patent this month.