Glenn, There is no question that current semiconductor technology can accommodate sub-micron design rules but remember that a pixel is not based on a single transistor. Whether you are talking about CCDs or CMOS imagers, the basic detector element will either consist of a multi-gate structure for charge collection and transfer or discrete photodiodes connected to transistors for signal amplification and readout. Plus, a color pixel normally requires 4 sub-pixels (a G pixel, a R pixel and 2 B pixels). Unlike a microprocessor, you don't gain performance by shrinking the imager size; in fact, it's quite the opposite. As to the manufacturing limitation you mentioned, the issue of limited field of exposure in steppers has been overcome by stitching techniques. Many companies including Philips and Tower Semiconductor have successfully demonstrated such processes. Berg Glenn Stewart wrote: 1.5 micron technology is old technology in the semiconductor business. I work for Intel Corp., and I can tell you that we are currently manufacturing microprocessors using .25 micron technology, and that we will be using .18 micron technology within 2 years. The biggest problem is the overall size of the sensor. A 24x36mm sensor has a diagonal measurement of about 43mm. This is nearly twice the size that can be reliably manufactured, due to the optics in the photolithography process. (They're Nikon, by the way.) _________________________________________________________ DO YOU YAHOO!? Get your free @yahoo.com address at http://mail.yahoo.com
