SanDisk gets key flash EEPROM patent

Electronic News, March 10, 1997 by Andrew MacLellan

San Jose, Calif.--SanDisk has been granted what it is calling a "fundamental" patent relating to flash EEPROM memory, one which the company said will both solidify its technology position and strengthen its case in an ongoing legal tussle with Samsung Electronics over other flash patents.

According to SanDisk, the new patent was issued Feb. 11, about two weeks before a U.S. International Trade Commission (ITC) judge found Samsung to be in violation of two related flash patents held by SanDisk (EN, March 3). That ruling is now before the full trade commission which will make a final determination by May 26. A decision in SanDisk's favor could result in Samsung NAND-based flash chips and products being barred from sale in the U.S.

"The findings of the ITC judge and the awarding of this new patent significantly strengthen SanDisk's overall intellectual property position in the flash industry," said SanDisk president/CEO Eli Harari.

The newly issued "Flash EEPROM System" patent (U.S. patent 5,602,987) protects SanDisk's flashdisk and CompactFlash solid state flash memory cards, which resemble magnetic disk drives in their ability to store data but contain no moving parts and are claimed to be more rugged and substantially less power hungry. According to SanDisk, the patent extends to several improvements which have been designed into the flash chip architecture, including selective multiple sector erase, remapping of bad memory cells or sectors and use of a write cache to reduce the number of writes to the flash EEPROM memory.

Although the new patent was issued nearly a month ago by the U.S. Patent and Trademark Office to Mr. Harari, Robert Norman and Sanjay Mehrotra, SanDisk did not publicize the award until recently. Nelson Chan, SanDisk VP of marketing, said there was no connection between the findings of the ITC judge and the timing of the patent announcement.

The new patent is not among those to be ruled on by the ITC, and SanDisk would not say if it will figure in another flash-related imbroglio which it and Samsung are attempting to settle in a San Jose, Calif., U.S. District Court. As part of that suit, Mr. Harari had previously stated that SanDisk may add to the list of five patents it now claims Samsung is violating. For its part, Samsung has asked that the five patents be set aside and is charging SanDisk with infringing two of its own patents.

To date, SanDisk has signed flash cross-licensing agreements with small form factor flash storage card makers Intel and Sharp. Toshiba, which sells the Solid State Floppy Disk Card (SSFDC) and has a flash cross-licensing agreement with Samsung, has no such agreement with SanDisk. Mr. Chan would not say if Toshiba is a potential target of legal action.

"We have made it clear that we want to protect our intellectual property rights, and we continue to evaluate other people's technology," said Mr. Chan. "But at this point we're not saying anything in addition to what we've made public in regard to Samsung or the cross-licensing agreements we have already signed."

Through the CompactFlash Association, SanDisk has made its CompactFlash storage technology interface and form factor specification open to all comers on a royalty-and license-free basis, but the offer does not extend to the company's ATA controller architecture.

"We are saying we have a fundamental patent here--part of a fairly large patent portfolio--but we believe people can build an ATA Type II card or CF card with their own controller and their own technology without violating SanDisk flash patents," said Mr. Chan.