Sandeep M Mehta

US Patent:

7378335, May 27, 2008

Filed:

Nov 29, 2005

Appl. No.:

11/288828

Inventors:

Steven R. Walther - Andover MA, US
Ukyo Jeong - Eugene OR, US
Sandeep Mehta - Boxford MA, US
Naushad K. Variam - Marblehead MA, US

Assignee:

Varian Semiconductor Equipment Associates, Inc. - Gloucester MA

International Classification:

H01L 21/425

US Classification:

438528, 257E21334

Abstract:

A method for fabricating a semiconductor-based device includes providing a substrate including a semiconductor layer, forming a gate dielectric layer on the semiconductor layer, forming a plasma including deuterium, plasma implanting deuterium from the plasma into the substrate, and annealing the substrate to promote passivation of the interface between the dielectric layer and the semiconductor layer.

US Patent:

7459703, Dec 2, 2008

Filed:

Aug 31, 2005

Appl. No.:

11/217700

Inventors:

Steven Walther - Andover MA, US
Ukyo Jeong - Andover MA, US
Sandeep Mehta - Boxford MA, US

Assignee:

Varian Semiconductor Equipment Associates, Inc. - Gloucester MA

International Classification:

G21K 5/10

US Classification:

25049221, 2504921

Abstract:

A system, method and program product for monitoring the beam angle integrity of an ion beam generated by an ion implanter system are disclosed. The invention utilizes at least one template with each template having a template surface that impedes the motion of an ion. Each template is configured such that an ion impacts the surface of the template if the trajectory of the template deviates from the optimum trajectory by a pre-determined maximum variance angle. The change caused by the impact of the ions with the template and/or a target is then measured to determine the amount of variance in the ion beam. Adjustments can then be made to the ion beam generator to correct for a misaligned beam.

US Patent:

7544957, Jun 9, 2009

Filed:

May 26, 2006

Appl. No.:

11/441633

Inventors:

Steven R. Walther - Andover MA, US
Sandeep Mehta - Boxford MA, US

Assignee:

Varian Semiconductor Equipment Associates, Inc. - Gloucester MA

International Classification:

H01J 37/08
G21K 5/10

US Classification:

25049221, 2504922, 250396 R, 250396 ML, 2502521, 25044211, 250398, 427523, 438527, 31511181, 118729, 118722

Abstract:

A method includes receiving an input signal representative of a desired two-dimensional non-uniform dose pattern for a front surface of a workpiece, driving the workpiece relative to an ion beam to distribute the ion beam across the front surface of the workpiece, and controlling at least one parameter of an ion implanter when the ion beam is incident on the front surface of the workpiece to directly create the desired two-dimensional non-uniform dose pattern in one pass of the front surface of workpiece relative to the ion beam. The beam may be a scanned beam or a ribbon beam. An ion implanter is also provided.

US Patent:

7544959, Jun 9, 2009

Filed:

Apr 8, 2008

Appl. No.:

12/099420

Inventors:

Steven R. Walther - Andover MA, US
Sandeep Mehta - Boxford MA, US
Naushad Variam - Marblehead MA, US
Ukyo Jeong - Andover MA, US

Assignee:

Varian Semiconductor Equipment Associates, Inc. - Gloucester MA

International Classification:

H01J 37/317
H01J 37/36
H01L 21/302

US Classification:

25049221, 2504922, 118723 R, 216 58

Abstract:

Methods and apparatus that introduce, within the ion implant chamber or an isolated chamber in communication therewith, the capability to remove contaminants and oxide surface layers on a wafer surface prior to ion implantation, are disclosed. The mechanisms for removal of contaminants include conducting: a low energy plasma etch, heating the wafer and application of ultraviolet illumination, either in combination or individually. As a result, implantation can occur immediately after the cleaning/preparation process without the contamination potential of exposure of the wafer to an external environment. The preparation allows for the removal of surface contaminants, such as water vapor, organic materials and surface oxides.

US Patent:

20060040499, Feb 23, 2006

Filed:

Aug 20, 2004

Appl. No.:

10/922710

Inventors:

Steve Walther - Andover MA, US
Sandeep Mehta - Boxford MA, US
Naushad Variam - Marblehead MA, US
Ukyo Jeong - Andover MA, US

International Classification:

H01L 21/302
C23F 1/00
C03C 25/68

US Classification:

438689000, 315111810, 11872300R, 156345100, 216058000

Abstract:

Methods and apparatus that introduce, within the ion implant chamber or an isolated chamber in communication therewith, the capability to remove contaminants and oxide surface layers on a wafer surface prior to ion implantation, are disclosed. The mechanisms for removal of contaminants include conducting: a low energy plasma etch, heating the wafer and application of ultraviolet illumination, either in combination or individually. As a result, implantation can occur immediately after the cleaning/preparation process without the contamination potential of exposure of the wafer to an external environment. The preparation allows for the removal of surface contaminants, such as water vapor, organic materials and surface oxides.

US Patent:

20060099830, May 11, 2006

Filed:

Nov 5, 2004

Appl. No.:

10/981831

Inventors:

Steven Walther - Andover MA, US
Sandeep Mehta - Beverly MA, US
Jay Scheuer - Rowley MA, US

Assignee:

Varian Semiconductor Equipment Associates, Inc. - Gloucester MA

International Classification:

C23C 14/00
C23C 16/00
H01L 21/31

US Classification:

438790000, 427523000, 11872300R

Abstract:

Methods and apparatus for plasma implantation of a workpiece, such as a semiconductor wafer, are provided. A method includes introducing into a plasma doping chamber a dopant gas selected from the group consisting of PF, AsF, AsFand mixtures thereof, forming in the plasma doping chamber a plasma containing ions of the dopant gas, the plasma having a plasma sheath at or near a surface of the workpiece, and accelerating the dopant gas ions across the plasma sheath toward the workpiece, wherein the dopant gas ions are implanted into the workpiece. The selected dopant gas limits deposition of neutral particles on the workpiece.

US Patent:

20060205192, Sep 14, 2006

Filed:

Mar 9, 2005

Appl. No.:

11/076695

Inventors:

Steven Walther - Andover MA, US
Sandeep Mehta - Beverly MA, US
Ukyo Jeong - Andover MA, US
Naushad Variam - Marblehead MA, US

Assignee:

Varian Semiconductor Equipment Associates, Inc. - Gloucester MA

International Classification:

H01L 21/425

US Classification:

438513000, 438514000, 438528000

Abstract:

A method for fabricating a semiconductor-based device includes disposing a substrate in a process chamber of a process tool, plasma implanting a dopant species from a plasma into a portion of the substrate in the process chamber, and plasma depositing a diffusion barrier on the implanted portion of the substrate prior to removing the at least one substrate from the process tool. The diffusion barrier can be deposited in the same chamber as that used for dopant implantation or a different chamber of the process tool.

US Patent:

20070048984, Mar 1, 2007

Filed:

Aug 31, 2005

Appl. No.:

11/217699

Inventors:

Steven Walther - Andover MA, US
Ukyo Jeong - Andover MA, US
Sandeep Mehta - Boxford MA, US
Naushad Variam - Marblehead MA, US

International Classification:

H01L 21/425

US Classification:

438533000

Abstract:

A system, method and program product for adjusting metal work function by ion implantation is disclosed. The invention determines the work function of the metal and determines a desired work function threshold for the metal. The desired work function threshold may be a range and is usually based on the work function of the substrate. An ion implanter system is then used to implant ions to at least a portion of the metal. The ion implantation is usually a high-energy ion stream including a material that is calculated to modify the work function of the metal. The ion implanter system continues to transmit the ion stream into the metal until the work function of the metal meets the desired work function threshold.