STM's MEMS Microactuator Makes Disk Drives Denser

It seems like there's a convention for just about every type of professional, but I honestly hadn't heard of the Diskcon USA 2001 event at the San Jose Convention Center until now. It looks to be a meeting of those involved in developing the myriad methods of digital storage and has sessions that include things like "Storage Technologies for the Future" and "Business Perspectives for the Storage Industry." A ton of purveyors of storage products will also be there so, hopefully, we'll see some interesting new products announced at the show in the days to come. One of the companies exhibiting is STMicroelectronics, which will be showing a prototype rotational microactuator produced using MEMS (Micro-Electro-Mechanical-System) technology. The thing is designed to position the read/write head on a hard drive with more precision, and allows the number of tracks per inch to be increased, which should improve drive density. STM says its MEMS microactuator is based on an electrostatic actuation approach where voltages applied to a stator and rotor cause angular movements of the rotor. In the disk drive the read/write head is attached to this rotor through special design and packaging that protects the moving parts from contamination but allows movement. Compared to electromagnetic actuation, STM's electrostatic method avoids magnetic fields close to the disk surface. The ST actuator provides a 1µ stroke applying voltages of just +/-10V and is also supposed to provide a high degree of linearity, simplifying the drive software. STM also says that due to the device's structure, the rotational actuator design is just about shock proof. The basic silicon micromachining steps used in MEMS fabrication are similar to those used in silicon chip manufacture, so existing production equipment can be used to make the new components.