At+t Corp.

At&t Bell Laboratories

Lucent Technologies Inc.

Chen-Hua D Yu

Kuo-Hua Lee

Kurt George Steiner

Ran-Hong Yan

Ajit S Manocha

Horng-Dar Lin

Chung-Ting Liu

A self aligned contact to the substrate in the region between two gate electrodes is formed by depositing a conformal dielectric layer and patterning to form a contact window. The conductive elements of the gate electrode are not contacted because of etch rate differentials between the conformal dielectric and the insulating elements of the gate structure.

Self-aligned contact window

A method of semiconductor fabrication having applicability to forming contacts to sources and drains especially in SRAM applications is disclosed. A dielectric and an overlying polysilicon conductor are formed and patterned thereby exposing a semiconductor substrate. A silicide layer is deposited, thereby contacting the polysilicon layer and the substrate. Subsequent patterning of the silicide layer using an oxide hard mask provides electrical contact between the polysilicon layer and the substrate without the risk of trenching into the substrate.

Integrated circuit fabrication having contact opening

A method of field oxide formation which creates field oxides of comparatively uniform height between differently-spaced oxidation masks is disclosed. A patterned oxidation mask, typically silicon nitride, (possibly with underlying polysilicon) is formed. A blanket layer of polysilicon is formed and etched back, thereby filling spaces between closely-spaced portions of the oxidation mask and fillets between less-closely spaced portions. A thermal oxidation is performed to produce a field oxide. The field oxide has comparatively uniform height despite differences in oxidation mask spacing.

Poly-buffered LOCOS

An integrated circuit is described which has an electrical contact formed between a metallic silicide and .alpha.:Si. The method of integrated circuit manufacturing comprising the steps of: forming a layer of a metallic silicide; depositing a layer of .alpha.:Si on said metallic silicide at a temperature less than the recrystallization temperature; and increasing the conductivity of at least selected portions of said .alpha.:Si by ion implanting a species having the peak of its spatial distribution spaced from the .alpha.:Si-Silicide interface and the .alpha.:Si surface.

Integrated circuit with silicon contact to silicide

An interlevel dielectric comprised of phosphorus-doped glass surrounding the second polysilicon level of an SRAM cell is disclosed. The second polysilicon is generally a cell local interconnect. The phosphorus-doped glass layer efficiently getters sodium from underlying layers. The phosphorus-doped glass layer is utilized although another doped gettering layer may be used at a higher level of the circuit.

Integrated circuit fabrication with interlevel dielectric

A semiconductor integrated circuit, and process for its manufacture, are disclosed which contains both n.sup.+ and p.sup.+ gates that do not pose a risk of dopant interdiffusion. Both n.sup.+ and p.sup.+ gates may be fabricated by conventional means. The gate structures are severed over the tub boundaries. A titanium nitride interconnective layer is deposited and patterned over the gates. The interconnective layer preserves connectivity between the n.sup.+ and p.sup.+ gates without risk of deleterious dopant interdiffusion.

Integrated circuit fabrication

A method of forming a planarized or smoothed dielectric or other material layer upon a partially fabricated intergrated circuit is disclosed. Conventional planarization techniques involve deposition of a dielectric or other material layer followed by anisotropic etchback. Unfortunately, some commercial equipment tends to etch the center of the wafer faster than the edges. The disclosed process forms a layer which is thicker in the central region than the edge region. Thus, when the disclosed process is followed by a conventional etchback, a planar dielectric or other material layer over the entire wafer is formed. Other aspects of the invention include processes and apparatus for producing smooth deposition and etching by control of the impedance of the etching and/or chemical precursor gases.

Method for forming dielectric

A method for forming transistors having sublithographic features, for example, gates, is disclosed. A patterned hardmask (formed, for example from PETEOS) is created overlying oxide and polysilicon layers. The dimensions of the hardmask are reduced by isotropic etching. The reduced-dimension hardmask is used with an anisotropic etching process to define a reduced-dimension feature such as a gate.

Transistor gate formation

A method of fabricating integrated circuits is disclosed. A layer of doped silicon dioxide is deposited over a partially fabricated integrated circuit. The doped silicon dioxide is heated to permit it to attract sodium ions. After the doped silicon dioxide has been heated, it is removed by an etching process which exhibits great selectivity to the remaining underlying portion of the integrated circuit.

Method of reducing ionic contamination in integrated circuit fabrication

A method of semiconductor integrated circuit fabrication including a technique for forming punch-through control implants is disclosed. After gate formation, a dielectric is formed which covers the gate and exposed portions of a semiconductor substrate. The dielectric is formed by a process which makes that portion of the dielectric adjacent the gate sidewalls more vulnerable to wet etching than those portions of the dielectric which are adjacent the top of the gate and the exposed substrate. The dielectric is then subsequently etched to form channels adjacent the gate which exposed the substrate and served to collimate an ion implantation beam. The remaining portions of the dielectric may then be stripped away and conventional procedures employed to form source and drain. Illustratively, the dielectric is formed from TEOS to which NF.sub.3 is added during the deposition process. The addition of NF.sub.3 makes that portion of the dielectric which forms adjacent the gate sidewalls particularly vulnerable to hydrofluoric acid etching while those portions of the dielectric covering the substrate and covering the gate are not so vulnerable.

Integrated circuit and manufacture

A method for forming a twin tub semiconductor integrated circuit is disclosed. A portion of a semiconductor substrate is masked by oxide, nitride and photoresist. P-type dopant is directed towards the other portion of the substrate. Subsequently, the photoresist is removed and a protective oxide is grown over the p-tub, thereby driving the dopant into the substrate. Next, an n-type ion implantation is performed to create the n-tub. The n-type ions are directed at the substrate at an angle which is away from normal incidence. The angular direction of the n-type dopants permits the use of smaller screen oxides over the n-tub and smaller protective oxides over the already-formed p-tub. When all of the protective oxides have been removed, the inventive technique provides a twin tub substrate having a comparatively smooth upper surface.

Transistor fabrication of a twin tub using angled implant

A method of semiconductor integrated circuit fabrication which provides a tapered window and a smoothed dielectric. A trench is made by etching through patterned photoresist into a dielectric. Then the corners of the trench are smoothed by thermal flow. Next the trench is etched downward by RIE blanket etchback. A window with tapered sides is thereby opened to the substrate and the dielectric is simultaneously smoothed.

Integrated circuit window etch and planarization

A workpiece is formed comprising a silicon substrate covered by four successive layers of silicon dioxide, undoped polysilicon, undoped WSi.sub.2 and a top layer of silicon dioxide on silicon nitride. The four layers are patterned to provide gate electrode structures each comprising the four layers. The workpiece is covered with a masking layer and the top layer of each structure is exposed through the masking layer. The top layers are then removed and ions of one conductivity type are implanted into the WSi.sub.2 layers of one group of gate electrode structures while another group of structures is masked, and ions of the other conductivity type are implanted into the WSi.sub.2 layers of the second group while the first group is masked. Thereafter, doped regions are formed in the substrate adjacent to the gate electrode structures.

Method of fabricating semiconductor devices having electrodes comprising

A method of forming a planarized or smoothed dielectric or other material layer upon a partially fabricated integrated circuit is disclosed. Conventional planarization techniques involve deposition of a dielectric or other material layer followed by anisotropic etchback. Unfortunately, some commercial equipment tends to etch the center of the wafer faster than the edges. The disclosed process forms a layer which is thicker in the central region than the edge region. Thus, when the disclosed process is followed by a conventional etchback, a planar dielectric or other material layer over the entire wafer is formed. Other aspects of the invention include processes and apparatus for producing smooth deposition and etching by control of the impedance of the etching and/or chemical precursor gases.

Method and apparatus for forming integrated circuit layers

A method for anisotropically depositing a dielectric from a precursor gas in a reactor is disclosed. The method includes reduced pressure, reduced oxygen/precursor gas flow ratio, increased spacing between shower head and susceptor; and also a susceptor having a diameter greater than the diameter of the wafer.

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Allentown, PA, United States of America

Chen-Hua D Yu