At the heart of the tremendous advances of optical microlithography are the resists and the people who drove them to ever-higher performance. In 1980, a resist could reliably image around a k 1 of 1.0 to 0.8. Today without any other extreme RET, resists with anti-reflection coatings production imaging has extended resolution to 0.6 to 0.45 k 1 , effectively doubling the NA of the integrated imaging system. Manipulation of the interrelationships of the physics and chemistry of the imaging process has made this possible. History shows that resists must be designed to best utilize the image being formed in them and that a resist designed for one application may not work for another. This holds true for resolution enhancement techniques as well, for example the quality and brightness of a weak phase-shifted contact depends on the strength of its side lobe, however, if the side lobe is too bright it will print unless the resist is modified not to print it. Also as technology moves to smaller features severe proximity effects make it necessary to adjust resist performance to compensate for these effects. In this discussion we concentrate on the physical chemical effects that makes it possible to extend resolution using resolution enhancement techniques. We will concentrate on energy coupling into the film with high NA imaging at the diffraction limit, the reaction-diffusion reaction and the impact of acid and base diffusion in chemically amplified resists.Keywords: resist, resolution enhancement technique, RET, microlithography, chemically amplified resists, 248nm, 193nm, 157nm, simulator, antireflection coating, ARC
IntroductionThe cost of designing and taking to market an advanced semiconductor product is becoming prohibitively expensive. Delaying delivery of production quantities of a new chip can cost millions of dollars in lost margins. Having to retool mask sets can cost more than $1 million at the 130nm technology node and beyond. Lost productivity of a $2 billion factory can cost in the neighborhood of $1 million per day, and use of these facilities, as laboratories must be reduced to a critical minimum. When considering that it costs each integrated-device-manufacturer (IDM) and foundry $300 to $500 million to develop a new manufacturing technology-node, and in addition that a state-of-the-art chip like a microprocessor at the 130nm node costs $18 million to design and at the 90nm node costs around $50 million to design with a significant portion being nonrecurring-engineering costs (NRE), it becomes imperative that product is designed so that it not only achieves yield entitlement quickly but does so with the desired performance specifications.