At&t Bell Laboratories

At+t Corp.

Bell Telephone Laboratories

Lucent Technologies Inc.

Other

Agere Systems Inc.

Agere Systems Guardian Corp.

American Telephone and Telegraph, Co.

Donald L White

Martin Barry Feldman

Obert R Wood, Ii

George Gustave Zipfel, Jr

Stuart T Stanton

Donald M Tennant

Alan D White

Sheila Vaidya

Peter A Heimann

Eric L Raab

Tatiana E Jewell

Alastair A MacDowell

Bruno M La Fontaine

Theodore F Retajczyk, Jr

William A Johnson

A deformable holder, system, and process where long range errors (any of lithography, metrology, or overlay errors) between the image of a mask and an existing pattern on a wafer from a number of potential sources are corrected. The long range errors are determined using either a through-the-lens alignment metrology system or an around-the-lens metrology system. Deformation values are determined to compensate for the longe range errors. The deformation values are determined by either solving simultaneous equations or by finite-element linear-stress-analysis (FEA). The mask or wafer is then distorted, in-plane, by an amount related to the determined deformation values using an actuator such an a piezoelectric ceramic to push or pull the mask or wafer to substantially realign the projected image of the mask and the existing pattern on the wafer.

Holder, system, and process for improving overlay in lithography

A lithographic apparatus and process that utilizes dark-field imaging of mask features to introduce an image of those features into an energy sensitive resist material is disclosed. Dark field imaging is accomplished by utilizing off-axis illumination in combination with one or more masks. The zero-order off-axis illumination is lost from the system and is not captured from the downstream imaging optics. The mask or mask contains both lithographic features and non-imaged features. The non-imaged features are too small to be resolved by the imaging optics used to introduce the image into the energy sensitive material. The lithographic features and non-imaged features associated with a particular pattern feature are either present on the same mask, or decoupled where the non-imaged features are on one mask and the lithographic features are on a second mask.

Lithographic process for device fabrication using dark-field illumination

A lithographic process for semiconductor device fabrication is disclosed. In the process a patterned mask having a multilayer film formed on a substrate is illuminated by extreme ultraviolet (EUV) radiation and the radiation reflected from the pattern mask is directed onto a layer of energy sensitive material formed on a substrate. The image of the pattern on the mask is thus introduced into the energy sensitive material. The image is then developed and transferred into the underlying substrate. The multilayer film is inspected for defects by applying a layer of energy-sensitive film (called the inspection film) in proximity to the multilayer film and exposing the energy-sensitive material to EUV radiation. The thickness of the multilayer film is such that a portion of the EUV radiation is transmitted through the inspection film, reflected from the multilayer film and back into the inspection film. The exposed inspection film is then developed, and the developed inspection film is inspected to determine if it indicates the presence of defects in the underlying multilayer film.

Lithographic process for device fabrication using a multilayer mask

Remote positioning to submicron accuracy is based on comparison of two interference gratings, the first of constant phase, and the second segmented. Positioning corresponds with equal segment-by-segment overlap of an image of one grating superimposed on the other.

High resolution remote position detection using segmented gratings

Through-the-lens alignment during deep UV lithographic processing in the manufacture of VLSI is accomplished without shifting the mask or wafer from the exposure position. Introduction and extraction of alignment light of actinic wavelength depends on beam routing due to diffraction from an interference grating. The path of alignment light is within the focusing system but does not impinge on the focused pattern.

Sub-micron through-the-lens positioning utilizing out of phase segmented

The operating principle of the attenuated phase mask is incorporated in a reflecting structure for use with extreme ultraviolet radiation. A working projection-reduction system for use with 0.18 .mu.m and smaller features combines the mask with all-reflecting optics.

Pattern delineating apparatus for use in the EUV spectrum

The fabrication of integrated circuit devices built to design rules of 0.18 .mu.m and below uses patterning radiation in the EUV spectrum. Optimized processing conditions take advantage of independently developed EUV characteristics such as short resist absorption lengths.

Device fabrication using DUV/EUV pattern delineation

A single crystal fluorescent material is used in the conversion of a short wavelength image. Conversion to a long wavelength image in the visible spectrum permits use of conventional glass optics for visual observation of UV and x-ray images. An illustrative use is in inspection of masks designed for use in fabrication of large scale integrated circuitry built to submicron design rules.

Fluoresence imaging

Devices built to design rules .ltoreq.0.25 .mu.m are pattern delineated by use of synchrotron-emitted x-ray radiation using a condenser which collects over a collection arc of at least 100 mrad. Condenser designs provide for processing of collected radiation to tailor characteristics such as direction and divergence. Pattern delineation by proximity printing as well as by projection printing is described. Forms of projection printing include reduction ringfield projection as by 5:1 mask:image reduction.

Device fabrication entailing synchrotron radiation

Submicron device fabrication entailing ringfield x-ray pattern delineation is facilitated by use of a condenser including a faceted collector lens. The collector lens is constituted of paired facets, symmetrically placed about an axis of a laser-pumped plasma source. Each of the members of a pair produce an image of the entire illumination field so that inhomogeneities in illumination intensity are compensated within each composite image as produced by a particular pair.

Device fabrication entailing plasma-derived x-ray delineation

In an optical lithographical system (e.g., 100) for printing features of a patterned mask (e.g., 103) into a workpiece (e.g., 120), such as in a semiconductor device, a one- or two-dimensional (depending on the features of the mask) optical transmission phase-shift diffracting device (e.g., 107) is inserted between an optical condensor (e.g., 105) and the patterned mask whose features are to be printed into the workpiece. The diffracting device is designed so as to enable an imaging lens system (e.g., 102) to collect more than merely a single order of the resulting diffraction patterns of the features of the mask and, by varying the spatial periodicity of the diffracting device, to tailor the illumination incident on the mask in accordance with the features (e.g., 114, 115) of the mask.

Optical lithographical imaging system including optical transmission

Fabrication of integrated circuits--electronic, photonic or hydrid--permits attainment of higher device density. Pattern delineation with smaller design rules than previously associated with delineating radiation of given wavelength is the consequence of use of phase masks. Compared with earlier used, binary valued phase masks, the multiple values of those on which this fabrication depends permits improved effectiveness in lessening of edge-smearing radiation of consequence (of diffraction-scattered delineating radiation at feature edges). Phase masking may provide, as well, for feature generation by interference, and for reduced intensity of unwanted image hot spots by diffraction.

Sub-micron device fabrication with a phase shift mask having multiple

Expedient fabrication of phase masks providing for many values of phase delay for exiting pattern delineating radiation depends upon a two-step procedure. Such masks offer improvement in ultimate device fabrication relative to that offered by prior binary-valued masks. In the first step, which may be carried out coincident with introduction of device feature information, apertures of appropriate size and distribution are produced in the relevant mask layer; in the second step material surrounding such apertures is heated to result in backflow-filling. The consequential layer thinning is such as to introduce the desired local change in phase delay.

Sub-micron device fabrication

Imaging at sub-micron dimensions--at dimensions ordinarily thought to approximate those within diffraction limitations of the chosen imaging radiation--is expedited by use of a new category of phase masks. The new mask structure provides for phase shifting by use of waveguides. Waveguides of such dimensions, material, and spacing as to accommodate image resolution impairment, may consist of filled or unfilled apertures or of protuberances, all of constant length equal to the thickness of the mask layer in which constructed.

Sub-micron imaging

A lithography system is disclosed which is capable of doubling the spatial frequency resolution associated with conventional systems. A spatial filter, positioned to intercept the Fraunhofer diffraction pattern of the mask being exposed, is configured to prevent certain orders of the diffraction pattern (in most causes the O-order and .+-.2nd, 3rd, . . . orders) from reaching the wafer's surface. The remaining orders reaching the wafer surface (in most cases the .+-. first-order beams) will produce a cos-type interference pattern with a period half of that if the mask grating were imaged without spatial filtering. Therefore, for a system with a given magnification factor m, a mask grating with a period p will be exposed on the wafer surface as a grating with a period of p'=pm/2. Advantageously, the spatial filtering technique of the present invention allows for a variety of different structures (conventional gratings, chirped and phase-shifted gratings, grids, Fresnel zone plates, etc.), as well as structures of different sizes and orientations, to be included on one mask and transferred to the wafer with a single exposure cycle.

Growing community of inventors

Morris Plains, NJ, United States of America

Donald L White