International Business Machines Corporation

Daniel C Cole

Edward W Conrad

Orest Bula

William C Leipold

David V Horak

Jed Hickory Rankin

John Maxwell Cohn

Robert K Leidy

Randy William Mann

Ning Lu

Donald J Samuels

Paul William Pastel

Andrew J Watts

Archibald John Allen

Stephen E Knight

A method and structure for creating a photomask data set includes inputting a design data set, creating a simulated printed data set by applying a lithography simulation model to chosen levels of the design data set, merging each chosen level of the design data set with each corresponding level of the simulated printed data set in order to produce a merged design data set, applying at least one test to the merged design data set, correcting the design data set based on results of the test to produce a corrected design data set, repeating the creating of the simulated printed data, merging, applying the test and correcting using the corrected design data set until the corrected design data set passes the test, and outputting the corrected design data set as the photomask data set.

Interactive optical proximity correction design method

A method and structure for a photomask that includes a substrate having a first transmittance, a first pattern to be transferred to a photosensitive layer (the first pattern having a second transmittance lower than the first transmittance) and a second pattern having a third transmittance greater than the second transmittance and less than the first transmittance. The second pattern is adjacent at least a portion of the first pattern, and the substrate and the second pattern transmit light substantially in phase.

Method to control nested to isolated line printing

A structure and method of designing an integrated circuit includes generating at least one device shape, altering the device shape to comply with predetermined rules, forming a first hierarchical level abstraction around the device shape (where the first hierarchical level abstraction represents a perimeter of the device shape), preparing a first hierarchical level arrangement of first hierarchical level abstractions, altering the first hierarchical level arrangement to comply with the predetermined rules, forming a second hierarchical level abstraction around the first hierarchical level arrangement (where the second hierarchical level abstraction represents a perimeter of the first hierarchical level arrangement), preparing a second hierarchical level arrangement of second hierarchical level abstractions, and altering the second hierarchical level arrangement to comply with the predetermined rules.

Contextual based groundrule compensation method of mask data set generation

A structure for a semiconductor chip which includes a first region having first cells for storing and processing data, and a second region outside the first region having OPC structures, wherein the OPC structures comprise decoupling capacitors. The line widths of the active gates of first cells are the same size or similar in size as the OPC structures. The OPC structures reduce proximity effects of active devices in the first cells, and comprise N-type FETs and P-type FETs, that are located in the second region. The OPC structures may have a width greater than the first cells. The second region can be multiple OPC structures, whereby the second region comprises multiple decoupling capacitors. The active devices in the first cells are separated by a first distance and the OPC structures are separated from the active devices by the first distance.

Optical Proximity Correction Structures Having Decoupling Capacitors

A method and computer system are provided for checking integrated circuit designs for design rule violations. The method may include generating a working design data set, creating a wafer image data set, comparing the wafer image data set to the design rules to produce an error list and automatically altering the working design data set when the comparing indicates a design rule violation. The method further automatically repeats the creating, the comparing and the automatically altering until no design rule violations occur or no solution to the errors exists.

Auto correction of error checked simulated printed images

The present invention provides a method of forming nested and isolated images in a photosensitive resist. In the disclosed method, the entire surface of the photosensitive resist or selected regions thereof is exposed to a first mask having a set of nested, i.e. repeating pattern or grid images thereon, and then exposed to a second mask in order to remove unwanted portions of the nested image, so as to provide regions of nested and regions of isolated images in said photosensitive resist. The method may also be used to form regions having images in proximity to one another and regions having isolated images by exposing the entire surface of the photosensitive resist to a first mask having repeating patterns, and then removing entire or portions of the repeating patterns by exposure of the photosensitive resist with a second mask.

Method of forming resist images by periodic pattern removal

Fine feature lithography is enhanced by selectively providing exposures to correct for effects such as foreshortening, corner rounding, nested to isolated print bias, feature size dependent bias, and other image biases in semiconductor processing. These results are achieved by increasing the local exposure dose in critical areas of specific images, such as line ends and corners. The general process incorporates techniques which tailor the exposure dose as a function of position to achieve the desired final image shape. The techniques include contrast enhancement layers (CEL), scanning optical beams, and exposures with different masks. In one embodiment the process of forming a pattern comprises the steps of providing a substrate having a photosensitive coating, exposing the center area of the pattern on the photosensitive coating with one mask, and exposing ends of the pattern on the photosensitive coating without exposing the center area with a second mask. The second exposure overlaps the first exposure and may extend beyond the pattern but the second dose is much lower than the first dose.

Process for enhanced lithographic imaging

A structure and method for checking semiconductor designs for design rule violations includes generating a predicted printed structure (i.e., an ideal image) based on the semiconductor designs, altering the ideal image to include potential manufacturing variations, thereby producing at least two production images representing different manufacturing qualities, and comparing the production images to the design rules to produce an error list.

Error checking of simulated printed images with process window effects included

The distribution of ultraviolet light irradiated from an illumination source to optical elements of a projection exposure device is varied by an illumination aperture. The illumination aperture is formed with a plurality of openings which may be opened or closed independently to the passage of irradiating light. The size and shape of the opening formed by the plurality of openings of the illumination aperture is determined according to the particular image to be projected.

Micro adjustable illumination aperture

A method is presented here that enables one to improve the prediction for the printed structures of circuit patterns in a microchip, thereby potentially aiding in the design of the microchip circuitry. This method comprises the steps of determining, by applying process bias and corner curvature rules to a real mask image, a simulated structure for the mask used in optical projection lithography; and determining, by applying optical and process proximity correction rules to said simulated mask structure, a more accurate prediction for the structures printed on the wafer. Preferably the simulated mask structure is determined by applying a symmetric bias consistent with a mask build process to the real mask image, adjusting predetermined features of the real mask image such as corners or narrow lines, and applying a reverse symmetric bias to the adjusted real mask image.

Method of modifying a microchip layout data set to generate a predicted mask printed data set

A transmission controlled mask (TCM) for providing effective and accurate printing of images on a semiconductor wafer is defined. The transmission controlled mask (TCM) of the present invention includes opaque regions, clear regions, and transmission controlled (TC) regions, each region have different transmittance for reducing and/or eliminating the foreshortening which occurs in image printing. By employing the TCM of the present invention and adjusting the exposure time, images of lines and holes may be printed correctly with the same mask. The TCM of the present invention comprises a quartz substrate having a carbon layer and a chrome layer deposited on its surface.

Transmission control mask utilized to reduce foreshortening effects

A method of forming an image having reduced comer rounding in a photoresist layer is provided which comprises exposing a photoresist layer to a first mask having a first image, said first image having at least two edges; exposing said photoresist layer to a second mask having a second image, said second image having at least two edges, the second image edges being substantially rotated relative to the first image edges to produce a latent image in said photoresist layer having edges substantially rotated relative to the first and second image edges; and developing the photoresist layer to produce said image.

Method of forming sharp corners in a photoresist layer

A proximity correction serif design methodology is described that provides improved inner and outer corner rounding, line end shortening, as well as improvements in more general undesirable two-dimensional shape distortions introduced into the lithographic printing process due to proximity effects. Using this method, exact solutions are shown for the specialized cases of either coherent or incoherent illumination exposing a hypothetical resist that develops via a simple diffusion like mechanism. The basis of this method for predicting the positions and shapes of serifs is tied to the need to increase the components of high spatial frequency that are essentially lost due to diffraction, diffusion, dissolution, and etching related effects. The correct amount to increase the spatial components is determined in the coordinate space and makes use of an empirical characterization of these physical factors.

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Jericho, VT, United States of America

Daniel C Cole