| 摘要 |
<p>This method for photoemission inspection of via studs in integrated circuit packages is based on the large photoemission contrast between the metals used in integrated circuit manufacture and insulating contaminants which may have remained from previous fabrication steps. A light source (27) sheds a beam of photons having energies above the work function of said metals and below the work function of said insulators onto the via connection (18, 19, 24...26) under inspection. The electrons photoemitted from the metallization are detected by a channelplate detector (28, 29, 31) which is divided into a plurality of identical segments the size of which is chosen smaller than the smallest contaminant expected. An electron gun (34) supplies low-energy electrons for neutralizing charges occurring in the conducting parts on the surface of the integrated circuit package (21) owing to the induced photoemission of electrons from the via connections (18, 19, 24...26). The output signals from the channelplate detector (28, 29, 31) are compared (32) against pre-stored (33) ideal values representing perfect via connections.</p> |
