Samsung has turned up the heat in its legal battle with Rambus by asking a Virginia court to strip the memory technology developer of four disputed patents in a countersuit over alleged intellectual property infringement. The countersuit follows the decision by Rambus last week to add the Korean company as a defendant in its suit against four other companies deemed to be infringing its IPR over a range of memory technologies. That case is being heard in the U.S. District Court for the Northern District of California.

Rambus also terminated a DDR DSRAM licensing deal with Samsung, though this five-year deal was due to expire within weeks in any case.

The legal action is the latest in a series of court battles Rambus has been following against memory suppliers, including Hynix Semiconductor, Infinenon Technologies, Inotera Memories and Nanya Technology Group.

Samsung asked the Virginia court to declare four Rambus patents 'invalid and unenforceable'.

In its lawsuit, the Korean conglomerate uses the now well-worn assertion that Rambus used information it obtained as a member of a memory chip standards-setting body to secure additional patents, with the intention of later seeking to enforce those patents against the group's members. It also accuses Rambus of shredding documents related to the matter.

In March, Rambus agreed to settle its long-running patent case against Infineon after Infineon agreed to pay Rambus royalties.