Abstract: A clean-enclosure to protect a reticle from contamination when using extreme ultraviolet (EUV) lithography is disclosed. The clean-enclosure consists of frame and a cover attached to the frame. The cover contains an exposure window comprised of a thin film of silicon. This thin film window allows EUV light to pass through to the reticle and reflect onto the photoresist layer of a semiconductor substrate with minimal transmission loss. Also, a process for forming the silicon thin film exposure window is disclosed.

Abstract: A silicon-substrate based reflective photolithographic mask fabrication technique is described. The process begins with a multilayer, resonant reflecting substrate. A thin layer of silicon dioxide or other material capable of acting as an etch stop layer is deposited thereon. Then, a transmissive layer is deposited on the thin layer of etch stop layer. The transmissive layer is substantially transmissive to the wavelength of light used in the photolithography as well as capable of being selectively etched relative to the underlying etch stop layer. Then, the transmissive layer is etched to open preselected, absorptive areas. An absorptive layer is then deposited thereon. The absorptive layer is substantially absorptive to the wavelength of light used as well as capable of completely filling the opened areas of the transmissive layer. The absorptive layer is then planarized, and a thin protective cap is deposited thereon.

Abstract: During the fabrication of a photolithography mask, double defect-absorbing layers are incorporated to ensure the final mask structure is free of defects. The process begins with a resonant reflector substrate. First and second defect-absorbing layers cover the substrate. The first and second defect-absorbing layers are selected to be repairable if defects form, as well as can be etched selectively relative to each other as well as to the underlying substrate. The first defect-absorbing layer is coated with photoresist. The photoresist is patterned using photolithography. Next, the photoresist pattern is transferred to the first defect-absorbing layer through plasma etching. Any defects arising from the etching step are repaired. Next, the pattern formed in the first defect-absorbing layer is transferred to the second defect-absorbing layer, using the first defect-absorbing layer as a mask. Any defects arising from the etching step are repaired.

Abstract: A novel mask for photolithography in semiconductor processing and the mask fabrication method is disclosed. The mask includes a substrate, a patterned buffer layer, a patterned absorber layer above the patterned buffer layer, and a protective cap. The substrate preferably contains a multilayer resonant reflective surface. The buffer layer and protective cap are transmissive to the wavelength of light used in the photolithography. The absorber layer is absorptive to the wavelength of light used in the photolithography. The mask is fabricated by first depositing the buffer layer. The absorber layer is formed on the buffer layer. Both absorber layer and buffer layer are etched to create a pattern. A protective cap layer is then deposited on the patterned absorber layer and buffer layer, and the protective cap is planarized as needed to create a substantially smooth mask surface.

Abstract: A method and apparatus for patterning a photoresist layer, with an enhanced depth of focus, is disclosed. The photoresist layer is exposed in a projection system which includes a lens having a chromatic aberration coefficient. Several closely spaced, narrow bands of radiation from an excimer are used to irradiate a mask. Each band is focused on the photoresist layer at a different focal plane along the light axis, thereby providing an increased depth of focus in a single exposure.