Allyson Beuhler

Development of an HDI photovia process for portable products

The use of a “microvia” process for the fabrication of high density printed circuit boards and IC packages offers many advantages in terms of producing high interconnect density, cost competitive substrates for portable communications products. Motorola has put into production a sequential build HDI process that uses photoimageable dielectrics and semi‐additive copper metallization on a PWB substrate. Design capabilities for the current HDI process are 100μm/100μm line/space and 125μm /250μm via/pad. Plated through holes in the substrate are filled with a screen printable ink so that traces can be routed over the through hole area. This design capability meets routing and reliability requirements for current Motorola portable products. Future PWBs and IC packages, however, will need higher density features and higher performance materials. These features include finer line width, multiple HDI layers for routing dense SMT packages, low loss dielectrics for RF circuitry, higher Tg, and lower moisture dielectrics for DCA and IC package assembly.

High dynamic range CMOS image sensor with pixel level ADC and in-situ image enhancement

We describe a CMOS image sensor with pixel level analog to digital conversion (ADC) having high dynamic range (>100db) and the capability of performing many image processing functions at the pixel level during image capture. The sensor has a 102x98 pixel array and is implemented in a 0.18um CMOS process technology. Each pixel is 15.5um x15.5um with 15% fill factor and is comprised of a comparator, two 10 bit memory registers and control logic. A digital to analog converter and system processor are located off-chip. The photodetector produces a photocurrent yielding a photo-voltage proportional to the impinging light intensity. Once the photo-voltage is less than a predetermined global reference voltage; a global code value is latched into the pixel data buffer. This process prevents voltage saturation resulting in high dynamic range imaging. Upon completion of image capture, a digital representation of the image exists at the pixel array, thereby, allowing image data to be accessed in a parallel fashion from the focal plane array. It is demonstrated that by appropriate variation of the global reference voltage with time, it is possible to perform, during image capture, thresholding and image enhancement operations, such as, contrast stretching in a parallel manner.