DNQ-novolac resists

DNQ—novolac resist chemistry has proved to have remarkable dexibiUty and extendibiUty. First introduced for printing appHcations, DNQ—novolac resists have been available since the eady 1960s in formulations intended for electronics appHcations. At present, most semiconductor manufacturing processes employ this resist chemistry. Careful contemporary research and engineering support the continuing refinement of this family of materials. 

Fig. 16. Optical transmittance spectmm of a typical DNQ-novolac resist. ( ), The transmittance of a 1 p.m film after coating. (-), the transmittance of...

Unlike DNQ—novolac resists, CA-resist imaging characteristics are determined to a significant extent by thermally activated bimolecular chemistry taking place during postexposure processing. Since the polymer serves here as the reaction medium, its properties and state induence the course and... 

DNOC (4,6-dinitro-o-cresol), 13 283 14 349 DNQ-novolac photoresist film, optical absorption spectrum of, 15 163-164 DNQ-novolac resists, 15 162... 

Upon X-ray exposure, DNQ-novolac resists undergo unusual chemistry... 

The diazido-ort/io-naphthoquinone/novolac (DNQ/ novolac) photoresists have been the workhorse for the semiconductor industry for over 30 years and still continue to be the most widely used photoresists today. ° They may be utilized with different exposure wavelength technologies I-line (365 nm), G-line (436 nm), and even 248 nm. Although productivity requirements for the technology with 248 nm exposure have demanded the transfer to photoresists with a chemical amplification, the DNQ-novolac resists still remain to be the most widely used and constantly finding new areas of implementation. The modern state-of-the-art in the microdevices technology gives an opportunity to use the DNQ-novolac resists to print features as small as 0.25 In addition, these photoresists in the form... 

The resist system which supported the i-line technology for many years in an exclusive manner was so-called diazonaphthoquinone (DNQ)/novolac resists (Fig. 5). This type of resists originally invented for printing by Suss [2] is a two-component system consisting of a novolac resin and a photoactive compound (PAC), diazonaphthoquinone. The novolac resin is soluble in aqueous base in virtue of the acidic phenolic OH functionality. However, the lipophilic diazonaphthoquinone dispersed in the phenolic matrix inhibits the dissolution of the resin film in an aqueous base developer. UV irradiation of the photoactive compound results in formation of a highly reactive carbene, accompanied... 

The roots of DNQ-novolac resists stretches all the way back to the ozalid process, mentioned above, which dates to the invention around 1917 of the process for making architectural blueprint papers by Gustav Kogel (1882-1945) and... 

Sometime between 1930 and 1940, Oskar Siiss of the Kalle Company invented the DNQ/novolac resist system, spurred on perhaps by the motivation of combining the two functional groups involved in the azocoupling reaction of their blueprint chemistry into one molecule. ... 

In their search for higher-resolution resists and potential replacements for KTFR, lithographers tested many photosensitive coatings, one of which was the positive-tone printing plate material from the Kalle Company of Wiesbaden, invented by Oskar Siiss, and based on the DNQ-novolac resist system described above. This material turned out to be the first DNQ-novolac resist used in semiconductor lithography. 

Other characteristics of DNQ/novolac resists that have contributed to their lasting success in the semiconductor industry include their high etch resistance and the fact that they can be developed in environmentally benign aqueous base developers. In addition, the cyclized rubber/bis-azide negative tone resists did not image well at the Hg g-line, the exposure wavelength of the earliest commercially available wafer steppers, the introduction of which effectively brought about the complete and wholesale conversion of the IC industry to novolac resists from the cyclized rubber/bis-azide. ... 

---