Motorola Corporation

Numerical Technologies, Inc.

Michael E Kling

Kevin D Lucas

Alfred J Reich

Bernard J Roman

Hua-Yu Liu

Warren D Grobman

Chong-Cheng Fu

Paul G Tsui

Hak-Lay Chuang

Clyde H Browning

James Morrow

James N Conner

One embodiment of the invention provides a system for reducing incidental exposure caused by phase shifting during fabrication of a semiconductor chip. The system operates by identifying a problem area of likely incidental exposure in close proximity to an existing phase shifter on a phase shifting mask, wherein the problem area includes a polysilicon line passing through a field region of the semiconductor chip. The system places an additional phase shifter into the problem area on the phase shifting mask so that a regulator within the additional phase shifter protects the polysilicon line passing through the field region. This additional phase shifter has a wider regulator than the existing phase shifter, wherein the existing phase shifter is used to expose a polysilicon line in a gate region of the semiconductor chip.

Method and apparatus for reducing incidental exposure by using a phase shifter with a variable regulator

One embodiment of the invention provides a system that facilitates a semiconductor fabrication process to create a line end in a manner that controls line end shortening arising from optical effects, and is especially applicable in alternating aperture phase shifting. This system operates by positioning a first mask over a photoresist layer on a surface of a semiconductor wafer. This first mask includes opaque regions and transmissive regions that are organized into a first pattern that defines an unexposed line on the photoresist layer. The system then exposes the photoresist layer through the first mask. The system also positions a second mask over the photoresist layer on the surface of the semiconductor wafer. This second mask includes opaque regions and transmissive regions that are organized into a second pattern that defines an exposure region. This exposure region cuts through the unexposed line on the photoresist layer to create the line end in the unexposed line, without the optical line end shortening that arises from creating the line end with a single mask. The system then exposes the photoresist layer through the second mask.

Using double exposure effects during phase shifting to control line end shortening

Lithographic Proximity Correction (LPC) shapes are added (503) to a layer of a layout database file (501). Geometric criteria such as feature width are then used to filter the added LPC shapes (502). The LPC shapes are then modified (505) by determining which LPC shapes are within a predetermined distance from a shape in a layer of the second data base (504). The database file, including the modified LPC shapes, is then used to manufacture a set of lithographic masks (506). The lithographic masks are then used to pattern a set of wafers in the manufacture of integrated circuits (507).

Lithographic proximity correction through subset feature modification

Integrated circuit designs are continually shrinking in size. Lithographic processes are used to transfer these designs to a semiconductor substrate. These processes typically require that the exposure wavelength of light be shorter than the smallest dimension of the elements within the circuit design. When this is not the case, exposure energy such as light behaves more like a wave than a particle. Additionally, mask manufacturing, photoresist chemical diffusion, and etch effects cause pattern transfer distortions. The result is that circuit elements do not print as designed. To counter this effect the circuit designs themselves can be altered so that the final printed results better matches the initial desired design. The process of altering designs in this way is called Lithographic Proximity Correction (LPC). Square (142), cross (162), octagon (172), and hammerhead (202) serifs are added to integrated circuit designs by shape manipulation functions to perform two dimensional (2-D) LPC.

Two dimensional lithographic proximity correction using DRC shape

Integrated circuit designs are continually shrinking in size. Lithographic processes are used to pattern these designs onto a semiconductor substrate. These processes typically require that the wavelength of exposure used during printing be significantly shorter than the smallest dimension of the elements within the circuit design. When this is not the case, the exposure radiation behaves more like a wave than a particle. Additionally, mask manufacturing, photoresist chemical diffusion and etch effects cause pattern transfer distortions. The result is that circuit elements do not print as designed. To counter this effect the designs themselves can be altered so that the final printed results better match the initial desired design. The process of altering designs in this way is called Lithographic Proximity Correction (LPC). Edge assist shapes and edge biasing features are added to integrated circuit designs by shape manipulation functions to perform one dimensional (1-D) LPC.

One dimensional lithographic proximity correction using DRC shape

A process for fabricating a semiconductor device includes the formation of a lithographic reticle (20) having a lithographic pattern (18) overlying a reticle substrate (10). In one embodiment, a reticle inspection database incorporates altered resolution assisting features (30,32) to inspect the lithographic pattern (18). The dimensional difference between the reticle inspection database and the lithographic reticle is substantially equal to the process bias realized during reticle fabrication. Inspection of the lithographic reticle (20) using a reticle inspection database containing altered resolution assisting features reduces the false detection of defects and provides increased sensitivity in the reticle inspection process.

Process for producing and inspecting a lithographic reticle and

A process for designing and forming a reticle (40) as well as the manufacture of a semiconductor substrate (50) using that reticle (40). The present invention places outriggers (32, 34, 36) between features (30) in both dense and semi-dense feature patterns to assist in the patterning of device features. The width of the outriggers can be changed based on pitch and location between features in a semi-dense or dense feature pattern. In one embodiment, the outriggers can be manually or automatically inserted into the layout file after the locations of the attenuating features have been determined. The outriggers are not patterned on the substrate, but assist in forming resist features of uniform width.

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Austin, TX, United States of America

Michael E Kling