Planar multilevel interconnection technology employing a polyimide

A planar multilevel interconnection technology, called planar metallization with polymer (PMP), has been developed, which utilizes a polyimide known as PIQ (polyimide isoindroquinazoline-dione) as an interlevel dielectric. The PIQ is highly resistant to heat and is mechanically flexible. Its low impurity concentrations also make it very stable in semiconductors. The PMP processing techniques have been refined to the stage where ICs can be fabricated commercially. A PIQ film etchant forms fine via-holes up to 3/spl times/3 /spl mu/m/SUP 2/, and chip size can be reduced by placing bonding pads on the active region of the device. Highly reliable linear and 256-bit bipolar memory ICs have been realized through this technology.