Until EUV lithography becomes a reality, multiple patterning technologies such as triple litho-etch (LELELE), self-aligned double patterning (SADP), and self-aligned quadruple patterning (SAQP) are being used to meet the stringent patterning demands of advanced back-end-of-line (BEOL) technologies. For the 7nm technology node, patterning requirements include a metal pitch of 40nm or less. This ...
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