Effects of Residual Aberrations on Line-end Shortening in 193 nm Lithography
نویسنده
چکیده
This paper extends and further validates the methodology for calibrating 193nm chemically amplified resist models and applying the models to line-end shortening simulation in the presence of image imperfections [1]. SPLAT, an imaging simulator, is used to simulate the light intensity at the bottom of resist film and predict the resulted wafer patterns in the presence of lens aberrations. The mask critical dimensions (CD) were measured to exclude the mask CD error effects. The experiments were conducted at Texas Instruments on a 193nm scanner. The mask CD errors proved a major contribution to isolated-dense line CD bias on the wafer. The lens aberrations were shown to be critical to the choice of optimal imaging location and the through-focus CD variation. By finding the optimal image location and threshold photoacid concentration, this model can predict line CD through focus, pitch and feature size, with a RMS error of 5nm. However, this model is not adequate in predicting the narrow space between line ends due to the poor resist response in very low contrast areas. A variable threshold model based on trajectory dissolution rate assumption is proposed to predict the wafer CD in low contrast areas, which resulted in a RMS error of 24nm. Considering the large SEM measurement noise on 193nm resists, this error is reasonable and sufficient for OPC applications. Key word: 193nm lithography, resist, lens aberrations, model calibration, variable threshold model
منابع مشابه
Review of
Introduction Lithography with 157-nm fluorine lasers is rapidly emerging as a viable technology for the post-193-nm era [1–3]. In fact, it may become the technology of choice for 100to 70-nm nodes. It is attractive for several reasons, the most important being that it is fundamentally an extension of optical lithography at the longer wavelengths of 248 and 193 nm. Therefore, it holds the promis...
متن کاملAlternatives to Chemical Amplification for 193 nm Lithography
Research has been conducted to develop alternatives to chemically amplified 193 nm photoresist materials that will be able to achieve the requirements associated with sub-32 nm device technology. New as well as older photoresist design concepts for non-chemically amplified 193 nm photoresists that have the potential to enable improvements in line edge roughness while maintaining adequate sensit...
متن کاملImaging capabilities of resist in deep ultraviolet liquid immersion interferometric lithography
Liquid immersion lithography (LIL) extends the resolution of optical lithography to meet industry demands into the next decade. Through the use of exposure media such as purified water (n of 1.44 at 193 nm), it is possible to reduce minimum pitches compared with traditional air/vacuum exposures media by a factor of as much as 44%—a full technology node. Beyond this simple observation, there is ...
متن کاملStudy of Air Bubble Induced Light Scattering Effect On Image Quality in 193 nm Immersion Lithography
As an emerging technique, immersion lithography offers the capability of reducing critical dimensions by increasing numerical aperture (NA) due to the higher refractive indices of immersion liquids than that of air. Among the candidates for immersion liquids, water appears to be an excellent choice due to its high transparency at a wavelength of 193 nm, as well as its immediate availability and...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2002