International Business Machines Corporation

Toppan Printing Co., Ltd.

James P Levin

Joseph L Malenfant, Jr

Thomas Benjamin Faure

Steven C Nash

Brian Neal Caldwell

Yuki Fujita

Raymond Walter Jeffer

Harold G Linde

Alfred Wagner

Steven D Flanders

Jeffrey F Shepard

Cuc Kim Huynh

Louis M Kindt

Emily E Fisch

Bruce Dale King

Shaun Crawford

Steven J Kirch

Carey T Williams

Michael R Schmidt

Lyndon S Gibbs

Aspects of the present invention relate to a test photomask and a method for evaluating critical dimension changes in the test photomask. Various embodiments include a test photomask. The test photomask includes a plurality of cells having a varied density pattern. The plurality of cells include a first group of cells arranged along a first line, the first group of cells having a first combined density ratio. The plurality of cells also include a second group of cells arranged along a second line, the second group of cells having a second combined density ratio. In the plurality of cells, the second combined density ratio for the second group of cells is equal to the first combined density ratio of the first group of cells. The varied density pattern is configured to substantially neutralize fogging effects.

Test pattern layout for test photomask and method for evaluating critical dimension changes

Methods for manufacturing a photomask, such as a chrome on glass photomask and a phase shift photomask are provided. A selective main chrome etch and a selective chrome overetch in the fabrication process provides a photomask having improved image quality and provides nominal image size control and image size uniformity across the photomask within current process flows and manufacturing steps. The selective etch process utilizes a main etch where the resist etch selectivity (amount of chrome removed to resist removed) is higher than in the overetch step in which the etch is more selective to removal of the resist layer relative to the chrome layer. To control the etch selectivities the composition of the etchant chemistry and/or the etchant reactor hardware settings (power, voltage, etc.) can be adjusted.

Method to etch chrome for photomask fabrication

An extreme ultraviolet lithography (EUVL) mask structure and associated method of formation. A first conductive layer is provided between a buffer layer and an absorber layer such that the buffer layer is on a multilayer stack. The multilayer stack is adapted to substantially reflect EUV radiation incident thereon. The absorber layer is adapted to absorb essentially all of EUV radiation incident thereon. A mask pattern is formed in the absorber layer. Formation of the mask pattern in the absorber layer is accompanied by inadvertent formation of a defect in the absorber layer. The defect is subsequently repaired. The mask pattern may be extended into the first conductive layer and into the buffer layer in a substantially defect-free process that exposes a portion of the multilayer stack. A second conductive layer may be provided on the absorber layer, wherein the mask pattern is also formed in the second conductive layer.

EUVL mask structure and method of formation

A method for developing copolymer photosensitive resists wherein a single solvent is used in conjunction with a puddle develop tool. The copolymer resist is ZEP 7000 and the developer is ethyl 3-ethoxy propionate (EEP).

Single component developer for use with ghost exposure

Single component developer for copolymer resists

A transmission grid is disposed in a conventional focussed ion beam system which includes an ion beam source emitter or ion gun, electrodes to turn the ion beam off and on, a beam defining aperture and electrostatic lenses to focus the ion beam onto a target. The elements of the ion beam system are disposed in a chamber which is provided with an inlet port and an outlet port. Gas is introduced into chamber via the inlet port where it is ionized by the ion beam into an ion plasma to be used to deposit materials onto the target. The transmission grid, is interposed which is a fine mesh, passive element is located in the path of the ion beam and reduces the ion beam current density by a desired value. The transmission grid may be configured with a variety of different transmissions so the current density can be adjusted in different increments depending on the gas/type of deposition to be performed.

Grid structure for reducing current density in focussed ion beam

An ion beam structure includes a gas container, such as a cylindrical can having first and second apertures through the center of the top and bottom walls respectively of the container such that a narrow ion beam is passed through the apertures and the center axis of the can and onto a target specimen such as a mask or chip or other article of manufacture disposed closely below the bottom of the can. The can may further include deflection means for applying voltages and/or magnetic fields to locations on the can (i.e., top, bottom, sides) to direct secondary charged particles such as electrons emitted from the specimen onto an electron detection means such that the structure functions as an imaging system. The electric and/or magnetic fields may be employed to increase the collection efficiency of the detector and thereby improve the quality of the image by increasing the signal to noise ratio. When the collected image produced by the secondary charged particles indicates that a repair or other modification be performed, a gas is introduced into the can from a gas reservoir via a tube. The gas, which contains first type particles (i.e. gold atom, tungsten atom, etc.) leaves the can via the bottom aperture and is adsorbed onto the nearby target specimen surface. The ion beam, containing second type particles (i.e. gallium ions) passes through the gas with minimum interaction and strikes the target specimen surface to decompose the adsorbed gas and the decomposed first type particles to provide the modification such as repair to the specimen (mask or chip) surface.

Gas delivery for ion beam deposition and etching

A method for marking a mask set to insure minimum mismatch between the masks when they are assembled into a set. Each mask in the set is evaluated against a known fixed standard, identified and marked such that when the set is assembled and utilized to produce an integrated circuit minimum mismatch between each element in each mask in the set will be realized.

Mask set mismatch

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South Burlington, VT, United States of America

James P Levin