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Dual-damascene Cu-interconnect is fabricated in a low-k, divinylsiloxane-benzocyclobuten (DVS-BCB) film to reduce signal transmission delay among circuit-blocks on a chip. One of difficulties is how to make the patterns of via-holes and interconnect-trenches in the DVS-BCB films using photo-resist masks precisely. We have developed a new BCB patterning process such as 'Simultaneous resist-etch-back' (SRECK) process, in which both of the patterned photo-resist film and the DVS-BCB film are etched back simultaneously to transfer the resist-patterns to the BCB film. Since the DVS-BCB film contains siloxane-group, the intensity of Si-related Emission Light (SEL) abruptly increases just after complete pattern transfer to the DVS-BCB. Using the SRECK process with SEL- monitoring, the dual-damascene Cu-interconnects are fabricated in the DVS-BCB film with precise dimension control. Finally, the BCB/Cu-interconnects are demonstrated in the top-layered global interconnects on the advanced MPUs.
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