International Business Machines Corporation

Carter W Kaanta

John Edward Cronin

James Gardner Ryan

Michael A Leach

Rosemary A Previti-Kelly

Pei-ing P Lee

Andrew J Watts

Randy William Mann

Howard Smith Landis

William J Cote

Badih El-Kareh

Matthew J Rutten

Brian J Machesney

Terrance M Wright

Stanley Roberts

Stuart R Martin

Paul A Farrar, Sr

Darrell Meulemans

Gordon Seth Starkey

Terry J Brabazon

Charles W Koburger, Iii

Paul A Farrar

Stephen Ellinwood Luce

Paul Christian Parries

Donald M Kenney

Robert Michael Geffken

William L Guthrie

Dale J Pearson

Thomas J Hartswick

Ronald R Uttecht

Jung H Yoon

Barbara Jean Luther

Michael L Kerbaugh

William J Patrick

John F Rembetski

William H Guthrie

Charles L Standley

John Andrew Hiltebeitel

Karey L Holland

Kathleen A Perry

Melanie M Chow

James K Paulsen

Robert C Bausmith

Susan F Cronin

A wiring structure with crossover capability is disclosed. The wiring utilizes a connection stud in a contact layer, beneath the plane of the otherwise-intersecting lines as a crossover. Thus, a first wire in a first metallization layer passes below a second wire in a second metallization layer by overlapping contact with the connection stud in the contact layer. In manufacturing the wiring structure of the present invention, no intervening insulative or via layers are used between the contact layer, the first metallization layer and the second metallization layer. However, care must be taken in device layout on the substrate to ensure that the connection stud is located above isolation areas rather than active device areas.

Integrated circuit chip wiring structure with crossover capability and method of manufacturing the same

A semiconductor chip with uniform topology includes a memory cell having a stacked capacitor self-aligned with a bitline. Thick insulation on the bitline and on interconnect wiring on supports circuits of the chip serves to provide the uniform topology and to provide for the self-alignment of the capacitor and bitline. Bitlines and support circuit interconnect wiring are both formed from the same level of metal but they are patterned in separate masking steps. The stacked capacitors are separated from each other by less than the minimum dimension of the photolithographic system used for fabrication.

DRAM cell with stacked capacitor self-aligned to bitline

A precision analog metal-metal capacitor is fabricated by forming a first capacitor plate in an insulation layer by forming a trench therein, depositing metal within the trench and planarizing the device. A thin dielectric layer is then deposited and patterned over the first capacitor plate. A second insulator is then deposited over the device and discrete openings etched therein to expose the insulation layer and first metal plate. Metal is deposited within the openings and planarized, thereby forming a contact to the first metal plate and the second metal plate of the capacitor.

Precision analog metal-metal capacitor

A method is provided for filling undesired sublithographic contact hole defects in a semiconductor structure caused by misalignment and undesirable overlap of metal line images over contact openings during photolithographic patterning. Unwanted contact between conductive metallization levels through these defects is thereby diminished. The method also provides self-alignment of the lines and contact holes for subsequent formation of stud via connections through which contact is desired to underlying metallization levels. Deposition of a conformal sacrificial material film fills the small, undesired sublithographic contact hole image formed and covers both mask surfaces through which the misaligned line image and contact opening were etched. Isotropic etching removes the conformal layer from all planar surfaces except those of the undesired sublithographic contact hole image. Translation into the underlying insulating layer results in the formation of only contact holes through which contact with underlying substrate metallization is desired. The method of the present invention may alternativety be practiced after the undesired sublithographic contact hole image is etched into the insulating layer to the underlying substrate metallization. Translation of sublithographic defects in a single mask layer overlying an insulating layer disposed over a substrate having metallization therein can also be avoided.

Self-aligned metallurgy

A method of forming sub-lithographic elements and spaces therebetween where the pitch may be reduced with continuously adjustable line and space dimensions, and a structure resulting from the method, are disclosed. A plurality of spaced convertible members are formed on a substrate. A portion of each member is then converted, thereby reducing the dimensions of the unconverted portion of the member while increasing the width of the member plus its converted layer. A conformal layer of material is then deposited over the converted members, followed by directional etching of the conformal layer. The unconverted portion of the member is then removed. The line and space dimensions can be continuously adjusted by altering either or both of the member's converted layer and conformal layer.

Reducing pitch with continuously adjustable line and space dimensions

The present invention provides a conductive structure for use in semiconductor devices. The structure can be used to interconnect the various diffusion regions or electrodes of devices formed on a processed semiconductor substrate to a layer of metal, to interconnect overlying layers of metal or to provide the gate electrode of an FET device formed on the surface of a semiconductor substrate. Various embodiments of the invention are described, but in broad form the active metallurgy of the present invention comprises a thin continuous layer to titanium--titanium nitride and a thick layer of a refractory metal, e.g. tungsten, overlying the titanium nitride layer.

Refractory metal-titanium nitride conductive structures

A method is provided for filling undesired sublithographic contact hole defects in a semiconductor structure caused by misalignment and undesirable overlap of metal line images over contact openings during photolithographic patterning. Unwanted contact between conductive metallization levels through these defects is thereby diminished. The method also provides self-alignment of the lines and contact holes for subsequent formation of stud via connections through which contact is desired to underlying metallization levels. Deposition of a conformal sacrificial material film fills the small, undesired sublithographic contact hole image formed and covers both mask surfaces through which the misaligned line image and contact opening were etched. Isotropic etching removes the conformal layer from all planar surfaces except those of the undesired sublithographic contact hole image. Translation into the underlying insulating layer results in the formation of only contact holes through which contact with underlying substrate metallization is desired. The method of the present invention may alternatively be practiced after the undesired sublithographic contact hole image is etched into the insulating layer to the underlying substrate metallization. Translation of sublithographic defects in a single mask layer overlying an insulating layer disposed over a substrate having metallization therein can also be avoided.

A semiconductor structure comprising two gate stacks of equal height but different composition. The two gate stacks each comprise two layers, with the first layer of each gate stack comprising the same material and the second layer of each gate stack comprising a different material. Each gate stack has an upper surface a distance `X` above the upper planar surface of a substrate of the semiconductor structure. Thus, the two gate stacks of different composition are of identical height.

Gate stack structure of a field effect transistor

Fabrication methods and resultant semiconductor structures wherein stack structures are selectively insulated from an enveloping layer of local interconnect material. The fabrication methods involve forming an overpass insulator(s) simultaneously with the underlying gate. Specifically, a layer of non-erodible insulating material is deposited over a layer of conductive material roughly in the area to comprise the stack structure. A simultaneous etch is then performed, and the resultant insulator portion is self-aligned to the underlying conductive material. The insulator portion insulates the stack from a subsequently deposited and planarized layer of local interconnect. Further processing options include decoupling silicide formation on selected stack structures, and various planarization and etching approaches for different available technologies. Specific details of the fabrication methods and resultant structures are set forth.

Method of making overpass mask/insulator for local interconnects

A semiconductor fabrication process for forming borderless contacts (130, 170, 172) using a removable mandrel (110). The process involves depositing a mandrel on an underlying barrier layer (100) designed to protect underlying structures (40) formed on a substrate (24). The mandrel is made from a material that will etch at a faster rate than the barrier layer so as to permit the formation of openings in the mandrel to be stopped on the barrier layer without penetrating such layer. After depositing a contact (130) in a first opening (120) formed in the mandrel, a second opening (140) is formed and a second contact (170) is deposited therein. Thereafter, the mandrel is removed and replaced with a layer of solid dielectric material (180).

Method of forming borderless contacts using a removable mandrel

A gray level mask suitable for photolithography is constructed of a transparent glass substrate which supports plural levels of materials having different optical transmissivities. In the case of a mask employing only two of these levels, one level may be constructed of a glass made partially transmissive by substitution of silver ions in place of metal ions of alkali metal silicates employed in the construction of the glass. The second layer may be made opaque by construction of the layer of a metal such as chromium. The mask is fabricated with the aid of a photoresist structure which is etched in specific regions by photolithographic masking to enable selective etching of exposed regions of the level of materials of differing optical transmissivities. Various etches are employed for selective etching of the photoresist, the metal of one of the layers, and the glass of the other of the layers. The etches include plasma etch with chloride ions to attack the chromium of the opaque layer, compounds of fluorine to attack the glass layer, and reactive ion etching with oxygen to attack the photoresist structure. Also, developer is employed for etching on hardened regions of resist in the photoresist structure.

Gray level mask

Disclosed is a process for producing multi-level conductor/insulator films on a processed semiconductor substrate having a conductor pattern. The insulator layers, each comprise a photosensitive polyimide polymer composition, and this allows the desired wiring channels and stud vias to be formed directly in the insulator layers, without the use of separate masking layers and resulting image transfer steps, thus providing a less cumbersome and costly process.

Process for forming multi-level coplanar conductor/insulator films

Method of making a gray level mask

A process is described which eliminates the need to account for mask alignment tolerances in forming vias for metallurgy by the use of a common vertical edge or common plane defined by a first mask representing a first level of interconnect. Subsequent masks for defining interconnecting vias and a second level of interconnect utilize at least one edge of the first mask pattern as a common element to define subsequent metal levels. The combination of an etch stop layer and an oversized second level mask enable the mask overlay to be eliminated.

Triple self-aligned metallurgy for semiconductor devices

Growing community of inventors

Colchester, VT, United States of America

Carter W Kaanta