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The chemical formation reaction of the solubility rate suppressed layer is studied, using Differential Scanning Chromatography (DSC), Thermogravimetric analysis (TGA), Gel Permeation Chromatography (GPC), and Fourier Transform Infrared Spectroscopy (FT-IR). From the results of these analyses, it is concluded that the formation of the solubility rate suppressed layer is caused by the esterification reaction under the deep UV flood exposure between novolak resin and unphotoreacted PAC(Photo Active Conpound). Furthermore the influence of the flood exposure ligth wavelength to the pattern profile is studied. The best wavelength must be chosen for the used resist thickness to form a good pattern profile.

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Fiber optic based reflectivity measurement during spray or spray/puddje development is effective for accurate critical dimension(CD) control However,there are some difficulties in using wafers with multilayer structures. This paper describes an improved method for end point detection of wafers with multilayer structures which consist of 160+/-lOnin SiN/2Onm Si02 /Si. The improvement has been done in the following way.

A new simple photoresist process for contrast enhancement of pattern profiles was published in 1987's SPIE symposium(771-42)(1). This process, which is called REL (Resolution Enhanced Lithography), consists of conventional novolak positive photoresist process steps and a deep UV flood exposure step between image exposure and development. The effect of REL process is caused by the reduction of the solubility rate in alkaline developer in the exposed areas. In this paper, we describe the influence of the flood exposure light wavelength on profiles of photoresist and a chemical formation reaction of the insoluble layer in alkaline developer. In the experiments, three types of light sources were used which had maximum intensities at wavelengths of 254nm, 313nm, and 365nm, respectively.The resist profiles depend on the wavelength of the deep UV flood exposure light. A good resist profile with rectangular cross section was obtained with the 365nm light source. In this case, the flood exposure light reaches the internal region of the resist and the dissolution rate reduction occurs not only at the surface but also in the bulk of the resist.