International Business Machines Corporation

Raman Gobichettipalayam Viswanathan

David Andrew Lewis

Kam Leung Lee

Wu-Song S Huang

Ronnen Andrew Roy

Lidija Sekaric

Raul E Acosta

James J Bucchignano

David Peter Klaus

Robert Fontana

Ching Hwa Tsang

Jordan Asher Katine

Gregory Michael Wallraff

Steven Erik Steen

Michael Joseph Rooks

Carl Eric Larson

Sharee Jane McNab

Stephen A Rishton

Dieter P Kern

Michael G Rosenfield

Walter W Molzen, Jr

Ernst Kratschmer

Porter Dean Gerber

Jerome Paul Silverman

Christopher J Ashton

A method of lithography is disclosed, which allows for independent resist process optimization of two or more exposure steps that are performed on a single resist layer. By providing for a separate post-exposure bake after each resist exposure step, pattern resolution for each exposure can be optimized. The method can generally be used with different lithographic techniques, and is well-suited for hybrid lithography. It has been applied to the fabrication of a device, in which the active area and the gate levels are defined in separate mask levels using hybrid lithography with an e-beam source and a 248 nm source respectively. Conditions for post-exposure bakes after the two exposure steps are independently adjusted to provide for optimized results.

Method for lithography for optimizing process conditions

Non-chemically amplified radiation sensitive resist compositions containing silicon are especially useful for lithographic applications, especially E-beam lithography. More particularly, radiation-sensitive resist compositions comprising a polymer having at least one silicon-containing moiety and at least one radiation-sensitive moiety cleavable upon radiation exposure to form aqueous base soluble moiety can be used to pattern sub-50 nm features with little or no blur.

High resolution silicon-containing resist

The negative resist compositions especially suitable for electron beam-based lithographic processes are obtained by using a polymeric component containing first silsesquioxane moieties functionalized with a first reactive group having a first crosslinking reactivity and a first dissolution rate in aqueous alkaline solutions, and second silsesquioxane moieties functionalized with a second reactive group having a second crosslinking reactivity and a second dissolution rate in aqueous alkaline solutions, said reactivities being different from one another and said dissolution rates being different from one another. These negative resists enable improved negative lithographic processes, especially in the context of mask-making and direct-write techniques using electron beam lithography. The negative resists are also useful more generally in methods of forming patterned material features and advantageously show reduced incidence of image collapse at smaller groundrules.

Method for using negative tone silicon-containing resist for e-beam lithography

A high-aspect ratio resist profile is obtained using a development process wherein a mixture of an alcohol and water is used as the developer. The alcohol/water mixture is non-toxic, and does not cause excess swelling and cracking of the resist during the development process.

High-aspect ratio resist development using safe-solvent mixtures of alcohol and water

The present invention is directed to a method of forming a new material layer or region near an interface region of two dissimilar materials, and an optional third layer, wherein at least one of said dissimilar materials or optional third is capable of being heated by microwave energy. The method of the present invention includes a step of irradiating a structure containing at least two dissimilar materials and an optional third layer under conditions effective to form the new material layer in the structure. An apparatus for conducting the microwave heating as well as the structures formed from the method are also described herein.

Microwave annealing

The present invention is a method of utilizing microwave energy for annealing of ion implanted wafers. By controlling the time, power density and temperature regime, it is possible to substantially fully anneal the wafer while limiting (and substantially preventing) the diffusion of dopant into the silicon, thereby producing higher performance scaled semiconductor devices. It is also possible, using different conditions, to allow and control the dopant profile (diffusion) into the silicon. Another aspect of the present invention is a method of forming a PN junction in a semiconductor wafer having a profile depth less than about 50 nm and a profile wherein the net doping concentration at said PN junction changes by greater than about one order of magnitude over 6 nm wherein the surface concentration of said dopant is greater than about 1&times;10,/cm,. The method includes providing a semiconductor wafer which can be single crystal or amorphous surface; implanting into said surface a dopant; exposing the surface to an energy source; the energy source being applied to supply energy at a rate such that the surface is substantially fully annealed before the dopant diffuses greater than about 50 nm. Another aspect of the present invention is having a PN junction formed between a first material of a first conductivity type and a second material of a second conductivity type, the junction has a depth of less than about 50 nm, in the first material the net doping concentration at the junction changes by greater than about one order of magnitude over 10 nm, the maximum value of said first conducting material of said wafer has a surface concentration of greater than about 1&times;10,/cm,.

Formation of ultra-shallow semiconductor junction using microwave annealing

The present invention is a method of utilizing microwave energy for annealing of ion implanted wafers. By controlling the time, power density and temperature regime, it is possible to substantially fully anneal the wafer while limiting (and substantially preventing) the diffusion of dopant into the silicon, thereby producing higher performance scaled semiconductor devices. It is also possible, using different conditions, to allow and control the dopant profile (diffusion) into the silicon. Another aspect of the present invention is a method of forming a PN junction in a semiconductor wafer having a profile depth less than about 50 nm and a profile wherein the net doping concentration at said PN junction changes by greater than about one order of magnitude over 6 nm wherein the surface concentration of said dopant is greater than about 1.times.10.sup.20 /cm.sup.3. The method includes providing a semiconductor wafer which can be single crystal or amorphous surface; implanting into said surface a dopant; exposing the surface to an energy source; the energy source being applied to supply energy at a rate such that the surface is substantially fully annealed before the dopant diffuses greater than about 50 nm. Another aspect of the present invention is having a PN junction formed between a first material of a first conductivity type and a second material of a second conductivity type, the junction has a depth of less than about 50 nm, in the first material the net doping concentration at the junction changes by greater than about one order of magnitude over 10 nm, the maximum value of said first conducting material of said wafer has a surface concentration of greater than about 1.times.10.sup.20 /cm.sup.3.

Formation of ultra-shallow semiconductor junction using microwave

An inventive mirror system for use in providing reflected X-ray radiation to a mask having pattern areas and opaque areas, comprising a plurality of parallel mirror segments which are vertically positioned with respect to each other at distances approximately equal to the widths of the corresponding opaque mask areas. In operation, radiation incident on each of the mirror segments is reflected to the patterned feature areas of the mask and skips over the opaque mask areas.

Mirror for providing selective exposure in X-ray lithography

A membrane mask structure for lithography using a radiation source and steps for fabricating and using the inventive membrane mask structure. The membrane mask structure comprises the following: a support structure formed of a material which is opaque to the lithographic radiation source and comprising support members separated by window areas; a membrane layer overlaying said support members and window areas, said membrane layer comprised of material which is transparent to said radiation source; and a pattern of feature material formed on or embedded in the membrane layer, said feature material being opaque to the radiation source and said feature pattern aligning with the window areas of said support structure. The mask structure may additionally include a plurality of reference markers formed in or on said membrane layer or on said support members of said support structure. In addition, the mask structure may include a protective pellicle of radiation-transparent material, which pellicle is mounted on the surface of said support members not associated with said membrane layer in such a way as to prevent any debris from contacting the membrane areas on which the feature pattern is formed.

Membrane mask structure, fabrication and use

A proximity effect correction method for electron beam lithography suitable for high voltages and/or very dense patterns applies both backscatter and forward scatter dose corrections. Backscatter dose corrections are determined by computing two matrices, a 'Proximity Matrix' P and a 'Fractional Density Matrix' F. The Proximity Matrix P is computed using known algorithms. The elements of the Fractional Density Matrix are the fractional shape coverage in a mesh of square cells which is superimposed on a pattern of interest. Then, a Dose Correction Matrix D is computed by convolving the P and F matrices. The final backscatter dose corrections are assigned to each shape either as area-weighted averages of the D matrix elements for all cells spanned by the shape, or by polynomial or other interpolation of the dose correction field defined by the D matrix. The D matrix also provides a basis for automatic shape fracturing for optimal proximity correction. Optionally, forward scattering correction may be included in the correction process. Forward scattering correction consists of boosting the dose applied to shape i by a factor b.sub.i. These boost factors are computed in a separate and independent step which considers only forward scattering. They are combined with those resulting from the backscatter correction scheme either by simple multiplication to form the final correction factors, or by inputting them to the backscatter correction scheme as numerical weights for each shape.

Growing community of inventors

Briarcliff Manor, NY, United States of America

Raman Gobichettipalayam Viswanathan