Abstract:
An illumination system of a microlithographic projection exposure apparatus comprises a dividing array (36; 136; 236) of optical elements (70a, 70b; 170a, 170b; 270). Each optical element has a positive optical power and produces a converging light beam (LBa, LBb). A spatial light modulator (38) is arranged between the dividing array (36; 136; 236) and a surface (76) and is configured to vary an irradiance distribution in the surface (78). The modulator comprises an array (40) of mirrors each being configured to deflect a converging light beam (LBa, LBb) produced by the associated optical element by a deflection angle that is variable in response to a control signal. Each mirror directs the deflected light beam towards the surface (76) where the deflected light beam produces a light spot (78a, 78b, 78c). At least two optical elements (70a, 70b; 170a, 170b; 270) of the dividing array (36; 136; 236) have different optical properties so that the spot sizes of the light spots are different.
Abstract:
An illumination system of a microlithographic projection exposure apparatus (10) comprises an optical integrator (52; 152) that includes an array (54c; 154b) of optical raster elements (56; 156). A condenser (72) superimposes the light beams associated with the optical raster elements in a common field plane (71). A modulator (62; 162; 262) modifies a field dependency of an angular irradiance distribution in an illuminated field. Units (60; 160; 260) of the modulator are associated with one of the light beams and are arranged at a position in front of the condenser (72) such that only the associated light beam impinges on a single modulator unit (60). The units are furthermore configured to variably redistribute, without blocking any light, a spatial and/or an angular irradiance distribution of the associated light beams. A control device (66) controls the modulator units (60; 160; 260) if it receives an input command that the field dependency of the angular irradiance distribution in the mask plane (78) shall be modified.
Abstract:
A microlithographic projection exposure apparatus has a measuring device (54), by which a sequence of measurement values can be generated, and a processing unit (48) for processing the measurement values. To this end, the processing unit has a processing chain which comprises a plurality of digital signal processors (DSPl, DSP2, DSP3), the first digital signal processor (DSPl) in the processing chain being connected to the measuring device (54) in order to receive the sequence of measurement values. Furthermore, each subsequent digital signal processor (DSP2, DSP3) in the processing chain is connected to a respectively preceding digital signal processor (DSPl, DSP2) in the processing chain. The digital signal processors (DSPl, DSP2, DSP3) are programmed so that each digital signal processor (DSPl, DSP2, DSP3) processes only a fraction of the measurement values and generates processing results therefrom, and forwards the remaining fraction of the measurement values to the respective next digital signal processor (DSP2, DSP3) in the processing chain for processing.
Abstract:
An illumination system of a microlithographic projection exposure apparatus comprises a spatial light modulator (58) which varies an intensity distribution in a pupil surface (38). The modulator (58) comprises an array (62) of mirrors (64) that reflect impinging projection light (34) into directions that depend on control signals applied to the mirrors. A prism (60), which directs the projection light (34) towards the spatial light modulator (58), has a double pass surface (76) on which the projection light (34) impinges twice, namely a first time when leaving the prism (60) and before it is reflected by the mirrors (64), and a second time when entering the prism (60) and after it has been reflected by the mirrors (64). Pupil perturbation suppressing means are provided that reduce reflections of projection light (34) when it impinges the first time on the double pass surface (76), and/or prevent that light portions (78) being a result of such reflections contribute to the intensity distribution in the pupil surface (38).
Abstract:
A microlithographic projection exposure apparatus comprises an optical surface (46; M6) and a measurement device (90) which measures a parameter related to the optical surface at a plurality of separated areas on the optical surface. The measurement device comprises an illumination unit (92) which directs individual measuring light beams (94) towards the areas on the optical surface. Each measuring light beam illuminates at least a portion of an area, which is associated with the measuring light beam, and at least a portion of an adjacent area which is not associated with the measuring light beam. A detector unit (96) measures a property for each measuring light beam after it has interacted with the optical surface. An evaluation unit (102) determines the surface related parameter for a selected area on the basis of the properties determined by the detector unit (96) for the measuring light beam that is associated with the selected area, and for at least one measuring light beam that is associated with an area adjacent to the selected area.
Abstract:
A micromirror (24) of a micromirror array (22) in an illumination system (10) of a microlithographic projection exposure apparatus can be tilted through a respective tilt angle (α x , α y ) about two tilt axes (x, y). The micromirror (24) is assigned three actuators (E 1 , E 2 , E 3 ) which can respectively be driven by control signals (U 1 , U 2 , U 3 ) in order to tilt the micromirror (24) about the two tilt axes (x, y). Two control variables (SG x , SG y ) are specified, each of which is assigned to one tilt axis (x, y) and which are both assigned to unperturbed tilt angles (α x , α y ). For any desired combinations of the two control variables (SG x , SG y ), as a function of the two control variables (SG x , SG y ), one (E 1 ) of the three actuators is selected and its control signal (U 1 ) is set to a constant value, in particular zero. The control signals (U 1 , U 2 , U 3 ) are determined so that, when the control signals (U 1 , U 2 , U 3 ) are applied to the other two actuators (E 2 , E 3 ), the micromirror (24) adopts the unperturbed tilt angles (αx, αy) as a function of the two control variables (SG x , SG y ).
Abstract:
An illumination system of a microlithographic projection exposure apparatus (10) comprises a primary light source (30), a system pupil surface (70) and a mirror array (46). The mirror array (46) is arranged between the primary light source (30) and the system pupil surface (70) and comprises a plurality of adaptive mirror elements (M ij ). Each mirror element (M ij ) comprises a mirror support (100) and a reflective coating (102) and is configured to direct light (34) produced by the primary light source (30) towards the system pupil surface (70). Preferably the mirror elements (M ij ) are tiltably mounted with respect to a support structure (110). According to the invention the mirror elements (M ij ) comprise structures (100, 102) having a different coefficient of thermal expansion and being fixedly attached to one another. A temperature control device (90) is configured to variably modify the temperature distribution within the structures so as to change the shape of the mirror elements.
Abstract:
In a method for operating an illumination system (12) of a microlithographic projection exposure apparatus (10), a set of illumination parameters that describe properties of a light bundle which converges at a point (72) on a mask (14) to be illuminated by the illumination system (12), is first determined. Optical elements (26, 36, 44, 46, 74, 76) whose optical effect on the illumination parameters can be modified as a function of control commands are furthermore determined, as well as sensitivities with which the illumination parameters react to an adjustment of the optical elements, induced by the control commands. The control commands are then determined while taking the previously determined sensitivities into account, such that deviations of the illumination parameters from predetermined target illumination parameters satisfy a predetermined minimisation criterion. These control commands are applied to the optical elements, before the mask (14) is illuminated.
Abstract:
Bei einem Verfahren zur Bestimmung der Lage einer Symmetrieachse (20) einer asphärischen Linsenfläche (16) relativ zu einer Bezugsachse (30, 22) wird die Lage des Krümmungsmittelpunktes (21) des sphärischen Anteils der Linsenfläche (16) gemessen. Ferner wird eine Taumelbewegung gemessen, welche die Linsenfläche (16) während einer Drehung um eine Drehachse (30) beschreibt. Aus den auf diese Weise erhaltenen Meßwerten wird die Lage der Symmetrieachse (20) der asphärischen Linsenfläche (16) relativ zu der Drehachse (30) bestimmt Meßwerten. Eine zur Durchführung des Verfahrens geeignete Vorrichtung weist einen Autokollimator (36a; 136a) zur Messung des sphärischen Anteils der Linsenfläche (16) auf. Die Taumelbewegung wird mit einem zweiten Autokollimator (36b) oder einem Abstandssensor (136b) gemessen.
Abstract:
An illumination system for a microlithographic projection exposure apparatus comprises a light source (30) and an optical integrator (56) . The latter has first optical subelements (561X, 561Y, 562X, 562Y) and produces a plurality of secondary light sources (82) each emitting a light bundle. A condenser (62) effects a superposition of the light bundles in a mask plane (70) . At least one scattering structure (58, 60) comprises a plurality of individually designed second optical subelements that are arranged in front of or behind the secondary light sources. The first and second optical subelements are configured such that optical subelements illuminated with identical irradiance distributions are separated by more than 5 mm.