Hisato Nakamura

New patterned wafer inspection system with the function to classify fatal defects

The effective combination of the conventional in-line wafer inspection technique and yield prediction technique has become an important issue in order to reduce time for the development of LSI and to ramp the yield. At the last SPIE, we presented the change in the defect modes from conventional planarization process to CMP process and proposed the new inspection system for the CMP process. That is, the dark field type with the bright field optics which has the function to measure defect sizes. We now prose a new function to recognize automatically whether defects are either on or off the patterns. By monitoring the intensities of scattered light for the adjacent die at the positions where the defects are detected, the system can recognize that defects are either on or off the patterns. Using this new function, the patterned wafer inspection system can offer information about both the defect size and its fatality. As a result, we can evaluate the yield prediction and analyze the variation in the predicted yield quickly.

Photo quality 300-dpi A4-size printer using thermal dye transfer method

We have developed a 300 dpi A4-size printer using the TDT method for desk-top publishing images including pictures and characters. This printer consists of an engine part and an interface part. They are connected through a VME (Versa Module Europe) bus. The engine part has density compensation for keeping high uniformity and works as a one line printer. The interface part includes SCSI and Centronics I/F with 1 or 4 color plane memories. The most useful function is that it can print any length of paper size, for example A4/A5 size, letter size, U.S. legal size, or any longer size for a panoramic image.