Papers by Keyword: Resist

Abstract: Advance nanoscale patterning technology requires high resolution lithography, from ultraviolet (UV, i-line system) to deep ultraviolet (DUV, KrF system) until extreme ultraviolet (EUV), but the compatibility study of new resist types and wet etchant is lacking. The compatibility is defined as the duration of a photoresist being able to withstand in wet oxide etchant. Poor compatibility has potential resist lifting and/or penetration during wet etch process, which causes electronic device performance drifting. Currently, wet oxide etching is widely used in the gate oxide wet etch using patterned resist, as well as in the backside oxide removal with blanket resist front-side coverage. In this paper, we explore the compatibility and understand the impact factors, based on commonly used resist (i.e., KrF and i-line system resist) and wet etch chemicals (i.e. HF based etchant) in industry. It is important to do a quick and straightforward compatibility check before we implement new resists on actual product wafers, to prevent poor compatibility caused resist lifting and/or penetration during wet etch process. Based on oxide thickness check and resist lifting phenomena, it is found that resist baking condition, resist polymer type, resist composition, and lag time from resist coating to wet oxide etching all will affect the compatibility between HF based etchant and resist.

Abstract: It is well known that electron beam lithography is one of the potential candidates to fulfill of the demand of the miniaturization of the design rule of semiconductor integrated circuits beyond sub 100nm size with high reproducibility. It is also a fact that the resolution is recognized to depend on the various factors which are oriented to the machine and process conditions, for example, electron beam diameter, the intensity distribution of the beam itself, the resistance properties polymers, the development conditions, etc. Therefore, it is thought that it is impossible to be derivable directly and unambiguously from the resist material itself. In this study, the intrinsic resolution of the resist polymer was discussed based on the hypothesis that the resolution itself may be able to improve to the same size as the size of an electron beam profile, or less. The bi-layer structure ZEP520A/poly methyl glutar imide (PMGI) was proposed and tested. As for the results achieved, the contrast γ was improved constantly with a reduction in the development time and a decrease in the development temperature. The highest γ value, approximately 18, was obtained during development at the-20°C condition. An approximately 70nm with high aspect ratio pattern which is almost the same size of the beam pattern was obtained. This result provides an understanding how the intrinsic resolution of the resist material should be, and can be applied to other lithography methods. This process was applied to the actual electrode pattern making process. An approximately 100nm width of Copper nanowire as the gate electrode for the AlGaN/GaN HFET was successfully demonstrated. In addition, AlGaN/GaN HFET operated at about 73.5GHz, successfully.

Abstract: The development of new functional cleaning agents is strongly required for leading-edge LSI fabrication, such as resist removal process without any damage to low-k materials. For example, as excessive acid cleaning agents would damage such materials. Consequently, a low damage cleaning technique with no collapsing fine structures is also desirable. On the other hand, the concept of recycle of cleaning agents is an urgent issue for the reduction of cleaning cost. Therefore, both cleaning ability and easy recyclable function are essential for next generation cleaning agents. Fluorine-based cleaning agents have been widely used for cleaning, rinsing and drying process in the electronics industry. Asahi Glass Corporation (AGC) has commercialized various fluorine-based cleaning agents as AC-series (Hydrofluorocarbon: HFC) and AE-series (Hydorofluoroether: HFE). Typical properties of these compounds are summarized in Table I. Here we report the application of fluorine-based cleaning agents to ArF resist removal and the evaluation of the recycles.

Abstract: Nanocomposite materials based on poly(p-hydroxystyrene-co-2-methyl-2-adamantyl methacrylate-co-methacrylisobutyl-POSS) were synthesized and evaluated as EUV chemically amplified resists. Incorporation of 2-methyl-2-adamantyl and POSS groups into the matrix polymer made it possible to improve the dry-etch resistance, and excellent lithographic performance was obtained. The well-defined 250 nm positive patterns were obtained using a KrF excimer laser scanner, and 100 nm elbow patterns using an EUV lithography tool. The dry-etch resistance of this resist for a CF4-based plasma was comparable to that of poly(p-hydroxystyrene).