Tower invests in Crocus, tips MRAM foundry deal

Who is Crocus?
Crocus was first incorporated in France in 2004 with an initial grant from CEA Valorisation and FIST, the subsidiaries of CEA and CNRS, France's leading research organizations, dedicated to spinning off promising new technologies into the private sector. The MRAM technology that is the foundation on which Crocus is built was developed in the Grenoble-based Spintec research center.

Besides Tower, the company is also leveraging SVTC Technologies Inc.'s R&D foundry service to complete the integration of its second-generation MRAM technology. For Tower and SVTC, Crocus has purchased a full suite of dedicated magnetic-technology wafer processing tools for the deposition, annealing, patterning, and metrology of MRAM memory chips.

Many companies are developing first-generation MRAMs based on field-induced technologies, which have encountered various problems in the market. ''The first generation of MRAM technology has seen difficulties coming to market. Technical challenges hindering manufacturability center around three factors: stability, selectivity, and scalability,'' according to a white paper published by Hoberman on Crocus' Web site.

Crocus claims to be developing a second-generation MRAM technology, which promises to scale beyond 90-nm. The company is devising both standalone devices and IP. It is targeting its technology for the embedded and SRAM replacement markets, Hoberman said.

''The leading candidates for workable second generation MRAM technologies are called Thermal Assisted Switching (TAS) and spin torque,'' according to the paper. ''Spin Torque is being developed by multiple teams worldwide, but still has challenges in basic physics and materials to overcome in order to achieve market readiness.''

Crocus is pursing TAS technology, which can be applied to both field-induced and spin torque schemes. ''TAS operates by introducing the concept of 'Blocking Temperature' (or Tb) in a specially designed multilayered magnetic stack from which the MTJ is built,'' according to the paper.

MTJ stands for magnetic tunnel junction. MRAM memories require the use of millions of MTJs in a regular array structure, which makes the device a challenge to produce.