Abstract: A method for inspecting masks used to project patterns in photolithographic imaging comprises initially providing a photolithographic mask having a pattern field thereon, where in normal production use the pattern is transferred by a reduction projector as a demagnified pattern on a production substrate, and providing a movable field-defining aperture adjacent the mask, the aperture having a field area less than, and capable of defining a pattern subfield comprising only a portion of the entire photolithographic mask pattern field. The method then includes aligning the field-defining aperture with a pattern subfield comprising only a portion of the entire photolithographic mask pattern field. Using an energy source, the method includes projecting the pattern subfield onto a test substrate and exposing onto the test substrate the pattern subfield at a size between that normally exposed on a production substrate and the actual size of the pattern subfield on the photolithographic mask.

Abstract: A method is described for determining lens aberrations using a test reticle and a standard metrology tool. The method provides test patterns, preferably in the form of standard overlay metrology test patterns, that include blazed gratings having orientation and pitch selected to sample desired portions of the lens pupil. The method measures relative shifts in the imaged test patterns using standard metrology tools to provide both magnitude and sign of the aberrations. The metrology tools need not be modified if standard test patterns are used, but can be adapted to obtain additional information. The test reticles may be formed with multiple test patterns having a range of orientations and pitch in order to compute any desired order of lens aberration. Alternatively, single test patterns may be used to determine both the magnitude and sign of lower order lens aberrations, such as defocus or coma.

Abstract: A stencil-scattering mask for e-beam lithography includes four complementary sub-field reticles, each of which is exposed with one fourth of the total dose. “Doughnut” stencil shapes have four different patterns of struts, so that an area that is blocked by a strut in one shape is exposed in three other shapes.

Abstract: The present invention relates generally to a method for lithographically printing a mask pattern on a substrate, in particular a semiconductor substrate, wherein the mask pattern includes features with diverse pitches. These features may include device features such as vias or contact holes and lines in integrated circuits. The method comprises splitting the mask pattern into a plurality of masks, wherein one or more of the masks contains relatively tightly nested features and one or more of the masks contains relatively isolated features. Each of the plurality of masks is then successively exposed on a photoresist layer on the substrate. For each exposure, the exposure conditions, photoresist layer, other thin films layers, etching process, mask writing process, and/or mask pattern bias may be optimized for the tightly nested feature pattern or isolated feature pattern.

Abstract: A stencil-scattering mask for e-beam lithography includes four complementary sub-field reticles, each of which is exposed with one fourth of the total dose. “Doughnut” stencil shapes have four different patterns of struts, so that an area that is blocked by a strut in one shape is exposed in three other shapes.

Abstract: A metrology target mask for determining proper lithographic exposure dose and/or focus in a pattern formed in a layer on a semiconductor substrate by lithographic processing. The target mask comprises a mask substrate and a first, dose and focus sensitive mask portion on the mask substrate having a first array of elements comprising a plurality of spaced, substantially parallel elements having essentially the same length and width. Ends of the individual elements are aligned to form first and second opposing array edges, with the lengths of and spaces between the elements being sensitive to both dose and focus of an energy beam when lithographically printed in a layer on a semiconductor substrate. The target mask also includes a second, dose sensitive mask portion on the mask substrate having a second array of elements comprising a central element having a length and a width, and a plurality of spaced, substantially parallel outer elements having a length and a width.

Abstract: The present invention relates generally to a method for lithographically printing a mask pattern on a substrate, in particular a semiconductor substrate, wherein the mask pattern includes features with diverse pitches. These features may include device features such as vias or contact holes and lines in integrated circuits. The method comprises splitting the mask pattern into a plurality of masks, wherein one or more of the masks contains relatively tightly nested features and one or more of the masks contains relatively isolated features. Each of the plurality of masks is then successively exposed on a photoresist layer on the substrate. For each exposure, the exposure conditions, photoresist layer, other thin films layers, etching process, mask writing process, and/or mask pattern bias may be optimized for the tightly nested feature pattern or isolated feature pattern.

Abstract: A metrology apparatus for determining bias and overlay errors in a substrate formed by a lithographic process includes an aperture between the objective lens and the image plane adapted to set the effective numerical aperture of the apparatus. The aperture is adjustable to vary the effective numerical aperture of the apparatus and the aperture may be non-circular, to individually vary the effective numerical aperture of the apparatus in horizontal and vertical directions. To determine bias and overlay error there is provided a target having an array of elements on the substrate, the array comprising a plurality of spaced, substantially parallel elements having a length and a width, the sum of the width of an element and the spacing of adjacent elements defining a pitch of the elements, edges of the elements being aligned along a line forming opposite array edges, the distance between array edges comprising the array width.

Abstract: A metrology apparatus for determining bias or overlay error in a substrate formed by a lithographic process includes an aperture between the objective lens and the image plane adapted to set the effective numerical aperture of the apparatus. The aperture is adjustable to vary the effective numerical aperture of the apparatus and the aperture may be non-circular, for example, rectangular, to individually vary the effective numerical aperture of the apparatus in horizontal and vertical directions. To determine bias or overlay error there is provided a target having an array of elements on a substrate, the array comprising a plurality of spaced, substantially parallel elements having a length and a width, the sum of the width of an element and the spacing of adjacent elements defining a pitch of the elements, edges of the elements being aligned along a line forming opposite array edges, the distance between array edges comprising the array width.

Abstract: A test photomask comprising a fresnel zone target (FZT) pattern may be used to verify the adjustment of a precision projector illumination system of an image projection system. The method comprises the steps of creating the FZT pattern on a photomask, projecting a pupil diagram onto an image plane using the FZT pattern, and evaluating the pupil diagram to determine the illumination system adjustment.

Abstract: Focus and exposure parameters may be controlled in a lithographic process for manufacturing microelectronics by creating a complementary tone pattern of shapes and spaces in a resist film on a substrate. Corresponding dimensions of the resist shape and space are measured and the adequacy of focus or exposure dose are determined as a function of the measured dimensions. Etching parameters may also be controlled by creating a complementary tone pattern of etched shapes and spaces on a substrate. Corresponding dimensions of the etched shape and space are measured and the adequacy of etching parameters are determined as a function of the measured dimensions.

Abstract: Focus and exposure parameters may be controlled in a lithographic process for manufacturing microelectronics by creating a complementary tone pattern of shapes and spaces in a resist film on a substrate. Corresponding dimensions of the resist shape and space are measured and the adequacy of focus or exposure dose are determined as a function of the measured dimensions. Etching parameters may also be controlled by creating a complementary tone pattern of etched shapes and spaces on a substrate. Corresponding dimensions of the etched shape and space are measured and the adequacy of etching parameters are determined as a function of the measured dimensions.

Abstract: Focus and exposure parameters may be controlled in a lithographic process for manufacturing microelectronics by creating a complementary tone pattern of shapes and spaces in a resist film on a substrate. Corresponding dimensions of the resist shape and space are measured and the adequacy of focus or exposure dose are determined as a function of the measured dimensions. Etching parameters may also be controlled by creating a complementary tone pattern of etched shapes and spaces on a substrate. Corresponding dimensions of the etched shape and space are measured and the adequacy of etching parameters are determined as a function of the measured dimensions.

Abstract: Focus and exposure parameters may be controlled in a lithographic process for manufacturing microelectronics by creating a complementary tone pattern of shapes and spaces in a resist film on a substrate. Corresponding dimensions of the resist shape and space are measured and the adequacy of focus or exposure dose are determined as a function of the measured dimensions. Etching parameters may also be controlled by creating a complementary tone pattern of etched shapes and spaces on a substrate. Corresponding dimensions of the etched shape and space are measured and the adequacy of etching parameters are determined as a function of the measured dimensions.

Abstract: Focus and exposure parameters may be controlled in a lithographic process for manufacturing microelectronics by creating a complementary tone pattern of shapes and spaces in a resist film on a substrate. Corresponding dimensions of the resist shape and space are measured and the adequacy of focus or exposure dose are determined as a function of the measured dimensions. Etching parameters may also be controlled by creating a complementary tone pattern of etched shapes and spaces on a substrate. Corresponding dimensions of the etched shape and space are measured and the adequacy of etching parameters are determined as a function of the measured dimensions.

Abstract: A method of determining the edge of an object by microscopy, such as an optical microscopy system or a scanning electron microscopy system. The edge of the object is viewed at a first focus value, and the image signal profile of the object edge is then measured at the first focus value. The object edge is then viewed at a second focus value different from the first focus value and the image signal profile of the object edge is measured at the second focus value. The location of the object edge is determined by comparing the image signal profiles of the object edge at the first and second focus values. For example, determination of the location of the object edge is by an isofocal point of the profiles. Alternatively, prior to the determination of the location of the object edge, the object edge is viewed at a third focus value different from the first and second focus values and the image signal profile of the object edge is measured at the third focus value.

Abstract: A high performance transistor includes mesa structures in a conduction region, favoring corner conduction, together with lightly doped mesa structures and mid-gap gate material also favoring operation in a fully depleted mode. Mesa structures are formed at sub-lithographic size and pitch as recesses or by epitaxial growth together with exposure of a resist by an interference pattern generation with illuminating radiation and multiple exposures using a mask shifted by a sub-lithographic distance. For an NFET, conduction electron and hole distribution profiles in the mesa structures and gate capacitance are adjusted with dielectric thickness, including deposition of oxide from a liquid solution at room temperature. Transconductance may be altered by change of the aspect ratio of the mesa structures. Lightly doped drain structures are also formed at sub-lithographic sizes by self-aligned processes.

Abstract: A simplified method of forming a phase shift structure for a lithographic mask includes the conformal deposition of a phase shift material, preferably having an index of refraction similar to that of the mask substrate, over a patterned layer of opaque material and exposed areas of the mask substrate corresponding to the pattern. The thickness of the opaque patterned layer, in combination with the conformal deposition preferably establishes a differentially altered optical path length to produce a phase shift which enhances contrast and increases illumination and resolution in fine patterns. In variant forms of the invention, the conformal deposition of either phase shift material or a sidewall spacer material is followed by an anisotropic removal of material to form the phase shift structure.

Abstract: Selective deposition of silica from a liquid phase solution of silica in hydrofluorosilicic acid through openings in a pattern of polyimide or similar organic material provides an optically improved phase shift mask structure for making lithographic exposures since deposition can be made substantially anisotropic to yield deposits of substantially uniform thickness. Deposition from the liquid phase is readily controlled and highly predictable control of deposition rate can be achieved by control of temperature of a low temperature deposition process. Therefore the optical quality of the mask need not be compromised by other structures, such as etch stop layers, otherwise necessary to achieve high phase shift accuracy and the deposits of phase shift material are substantially homogeneous. The process of deposition from the liquid phase can be stopped and started at will and the mask can be fabricated by a process which is substantially free from material-dependent or material-based process restrictions.

Abstract: A photolithography mask structure having a novel optical focus test pattern is described. The mask structure has a non-phase-shifted, transparent substrate and includes a phase shifter of other than 180.degree. disposed between spaced, parallel opposing lines such that an alternating pattern of non-phase-shifted material and phase-shifted material is defined transverse said parallel lines. When projected onto the surface of an object measurable shifts of the test pattern corresponds in direction and magnitude with the extent of system defocus. Various alternating test pattern embodiments are presented, all of which include at least one phase shift window of other than 180.degree. in relation to the mask substrate. Further, a monitoring system and a monitoring process are discussed employing the presented mask structures.