发明授权
US6093640A Overlay measurement improvement between damascene metal interconnections 有权
镶嵌金属互连之间的叠加测量改进

Overlay measurement improvement between damascene metal interconnections
摘要:
The outer box of a box-in-box alignment pattern can be difficult to see if implemented in damascene technology. The present invention solves this problem by forming its outline from a trench that is substantially deeper than the channel used to contain the damascene wiring. This trench is formed at the same time that first vias are etched so no extra processing steps are needed, only one extra mask. The metal used for the damascene wiring also lines the inside of the trench, resulting in a structure that is easily seen during the alignment step. These outer box trenches may be simple squares or they may be ring shaped (hollow squares). Three different embodiments of the invention are described.
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