Abstract: A method and apparatus for measuring the chromatic response of lithographic projection imaging systems is described. An apparatus for determining the lens aberrations for a lithographic projection lens is provided. A substrate coated with a suitable recording media is provided. A series of lithographic exposures are performed using an exposure source with variable spectral settings. The exposures are measured, and the measurements are used to determine a chromatic response of the projection imaging system.

Abstract: A process for providing illumination source conditions for the accurate determination Zernike tilt coefficients in the presence of coma is described. Large feature-shift coma sensitivity is simulated for a range of illumination conditions. The resulting source sensitivity data is modeled and a practical array of source shapes, each of which is optimized to eliminate the effects of transverse distortion due to third-order coma, is identified. The optimized set of source shapes can be used to more accurately determine Zernike terms a2 and a3 using a variety of methods. Knowledge of the lens distortion data in the absence of coma induced shifts can be entered into more traditional overlay regression routines to better identify systematic and random error.

Abstract: Techniques for producing emulations of lithographic tools and processes using virtual wafers and lithographic libraries are described. Emulating a lithographic projection imaging machine includes determining characteristics of the imaging machine, of a reticle used in the imaging machine, and of layer specific processes. Then performing emulation on a virtual wafer using the characteristics of the imaging machine, reticle, and layer specific processes. The machine characteristics determined include characteristics of an exposure source, lens aberration, exit pupil, mechanics, vibration, calibration offsets, or resist. The reticle characteristics determined include distortion, critical dimension, phase transmission error, mask clips, as drawn specifications, or mask sites. And, the layer specific process characteristics include machine model, machine setting identification, and field exposure sequencing.

Abstract: A process for providing illumination source conditions for the accurate determination Zernike tilt coefficients in the presence of coma is described. Large feature-shift coma sensitivity is simulated for a range of illumination conditions. The resulting source sensitivity data is modeled and a practical array of source shapes, each of which is optimized to eliminate the effects of transverse distortion due to third-order coma, is identified. The optimized set of source shapes can be used to more accurately determine Zernike terms a2 and a3 using a variety of methods. Knowledge of the lens distortion data in the absence of coma induced shifts can be entered into more traditional overlay regression routines to better identify systematic and random error.

Abstract: Gases evolved during photolithographic processing of chemically amplified photoresist systems are monitored to allow optimization of process parameters such as intensity and duration of applied heat or radiation. Specifically, during soft bake, evaporation of solvent gases is detected. During exposure and PEB, gases evolved during activation of the polymer resin component by the photoacid are detected. The intensity and/or duration of the heating or exposure are then varied to optimize resolution of the particular photolithography process. Residual gas analysis, diode laser spectroscopy, FT-IR spectroscopy, and electronic sensing may be utilized alone or in combination to monitor composition and/or concentration of evolved gases in accordance with the present invention.