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Chandrasekaram Ramiah

from Phoenix, AZ

Chandrasekaram Ramiah Phones & Addresses

  • 2546 E Granite View Dr, Phoenix, AZ 85048 (480) 706-0483
  • Austin, TX
  • San Antonio, TX

Publications

Us Patents

Method And Apparatus For Forming A Borophosphosilicate Film

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US Patent:
6345589, Feb 12, 2002
Filed:
Sep 4, 1998
Appl. No.:
09/148436
Inventors:
Chandrasekaram Ramiah - Phoenix AZ
Jeffrey L. Young - Los Gatos CA
Neil L. Pagel - Prescott AZ
Assignee:
Applied Materials, Inc. - Santa Clara CA
Motorola, Inc. - Scottsdale AZ
International Classification:
C23C 1600
US Classification:
118723E, 118723 R
Abstract:
A method and apparatus for improving film stability and moisture resistance of a borophosphosilicate film. The BPSG film according to the present invention is formed under plasma conditions in which high and low frequency RF power is employed to generate the plasma. The high frequency power supply provides most of the energy to break the molecules in the process gas thereby forming the plasma and promoting the necessary reactions. The low frequency power supply regulates and controls ion bombardment of the BPSG film as it is formed. In a preferred embodiment, nitrogen is included in the process gas and the low frequency RF power supply is used to precisely control ion bombardment during deposition processing thereby allowing incorporation of an unexpectedly elevated amount of nitrogen into the film further improving film stability.

Semiconductor Through Silicon Vias Of Variable Size And Method Of Formation

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US Patent:
7803714, Sep 28, 2010
Filed:
Mar 31, 2008
Appl. No.:
12/059123
Inventors:
Chandrasekaram Ramiah - Phoenix AZ, US
Paul W. Sanders - Scottsdale AZ, US
Assignee:
Freescale Semiconductor, Inc. - Austin TX
International Classification:
H01L 21/302
H01L 21/461
US Classification:
438712, 438667, 438714, 257E21218, 257E21233
Abstract:
A through-silicon via structure is formed by providing a substrate having a first conductive catch pad and a second conductive catch pad formed thereon. The substrate is secured to a wafer carrier. A first etch of a first type is performed on the substrate underlying each of the first and second conductive catch pads to form a first partial through-substrate via of a first diameter underlying the first conductive catch pad and a second partial through-substrate via underlying the second conductive catch pad of a second diameter that differs from the first diameter. A second etch of a second type that differs from the first type is performed to continue etching the first partial through-substrate to form equal depth first and second through-substrate vias respectively to the first and second conductive catch pads.

Through Substrate Vias For Back-Side Interconnections On Very Thin Semiconductor Wafers

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US Patent:
7935571, May 3, 2011
Filed:
Nov 25, 2008
Appl. No.:
12/277512
Inventors:
Chandrasekaram Ramiah - Phoenix AZ, US
Douglas G. Mitchell - Tempe AZ, US
Michael F. Petras - Phoenix AZ, US
Paul W. Sanders - Scottsdale AZ, US
Assignee:
Freescale Semiconductor, Inc. - Austin TX
International Classification:
H01L 21/44
US Classification:
438108, 438692, 438738, 257E21584
Abstract:
Through substrate vias for back-side electrical and thermal interconnections on very thin semiconductor wafers without loss of wafer mechanical strength during manufacturing are provided by: forming () desired device regions () with contacts () on the front surface () of an initially relatively thick wafer (′); etching () via cavities () partly through the wafer (′) in the desired locations; filling () the via cavities () with a conductive material () coupled to some device region contacts (); mounting () the wafer (′) with its front side () facing a support structure (); thinning () the wafer (′) from the back side () to expose internal ends (, etc. ) of the conductive material filled vias (, etc. ); applying () any desired back-side interconnect region () coupled to the exposed ends (, etc. ) of the filled vias; removing () the support structure () and separating the individual device or IC assemblies () so as to be available for mounting () on a further circuit board, tape or larger circuit ().

Through Substrate Vias

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US Patent:
8062975, Nov 22, 2011
Filed:
Apr 16, 2009
Appl. No.:
12/425159
Inventors:
Paul W. Sanders - Scottsdale AZ, US
Michael F. Petras - Phoenix AZ, US
Chandrasekaram Ramiah - Phoenix AZ, US
Assignee:
Freescale Semiconductor, Inc. - Austin TX
International Classification:
H01L 21/44
US Classification:
438667, 438620, 216 17, 257E21597, 257E21586
Abstract:
Through substrate vias (TSVs) are provided after substantially all high temperature operations needed to form a device region () of a first thickness () proximate the front surface () of a substrate wafer () by: (i) from the front surface (), forming comparatively shallow vias () of a first aspect ratio containing first conductors () extending preferably through the first thickness () but not through the initial wafer () thickness (), (ii) removing material (″) from the rear surface () to form a modified wafer () of smaller final thickness () with a new rear surface (), and (iii) forming from the new rear surface (), much deeper vias () of second aspect ratios beneath the device region () with second conductors () therein contacting the first conductors (), thereby providing front-to-back interconnections without substantially impacting wafer robustness during manufacturing and device region area. Both aspect ratios are desirably about ≦40, usefully ≦10 and preferably ≦5.

Methods For Forming Through-Substrate Conductor Filled Vias, And Electronic Assemblies Formed Using Such Methods

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US Patent:
8283207, Oct 9, 2012
Filed:
Mar 8, 2011
Appl. No.:
13/043094
Inventors:
Chandrasekaram Ramiah - Phoenix AZ, US
Douglas G. Mitchell - Tempe AZ, US
Michael F. Petras - Phoenix AZ, US
Paul W. Sanders - Scottsdale AZ, US
Assignee:
Freescale Semiconductors, Inc. - Austin TX
International Classification:
H01L 21/44
US Classification:
438108, 438692, 438738, 257E21584, 257E21499
Abstract:
Through substrate vias for back-side electrical and thermal interconnections on very thin semiconductor wafers without loss of wafer mechanical strength during manufacturing are provided by: forming desired device regions with contacts on the front surface of an initially relatively thick wafer; etching via cavities partly through the wafer in the desired locations; filling the via cavities with a conductive material coupled to some device region contacts; mounting the wafer with its front side facing a support structure; thinning the wafer from the back side to expose internal ends of the conductive material filled vias; applying any desired back-side interconnect region coupled to the exposed ends of the filled vias; removing the support structure and separating the individual device or IC assemblies so as to be available for mounting on a further circuit board, tape or larger circuit.

Through Substrate Vias

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US Patent:
8329579, Dec 11, 2012
Filed:
Jul 21, 2011
Appl. No.:
13/188084
Inventors:
Paul W. Sanders - Scottsdale AZ, US
Michael F. Petras - Phoenix AZ, US
Chandrasekaram Ramiah - Phoenix AZ, US
Assignee:
Freescale Semiconductor, Inc. - Austin TX
International Classification:
H01L 21/44
H01L 23/04
US Classification:
438667, 257696, 257E21597, 257E23011
Abstract:
Through substrate vias (TSVs) are provided after substantially all high temperature operations needed to form a device region of a first thickness proximate the front surface of a substrate wafer by: (i) from the front surface, forming comparatively shallow vias of a first aspect ratio containing first conductors extending preferably through the first thickness but not through the initial wafer thickness, (ii) removing material from the rear surface to form a modified wafer of smaller final thickness with a new rear surface, and (iii) forming from the new rear surface, much deeper vias of second aspect ratios beneath the device region with second conductors therein contacting the first conductors, thereby providing front-to-back interconnections without substantially impacting wafer robustness during manufacturing and device region area. Both aspect ratios are desirably about ≦40, usefully ≦10 and preferably ≦5.

3-D Circuits With Integrated Passive Devices

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US Patent:
8344503, Jan 1, 2013
Filed:
Nov 25, 2008
Appl. No.:
12/277519
Inventors:
Paul W. Sanders - Scottsdale AZ, US
Robert E. Jones - Austin TX, US
Michael F. Petras - Phoenix AZ, US
Chandrasekaram Ramiah - Phoenix AZ, US
Assignee:
Freescale Semiconductor, Inc. - Austin TX
International Classification:
H01L 23/34
US Classification:
257728, 257723, 257724, 438107, 438109
Abstract:
3-D ICs () with integrated passive devices (IPDs) () having reduced cross-talk and high packing density are provided by stacking separately prefabricated substrates () coupled by through-substrate-vias (TSVs) (). An active device (AD) substrate () has contacts on its upper portion (). An isolator substrate () is bonded to the AD substrate () so that TSVs () in the isolator substrate () are coupled to the contacts () on the AD substrate (), and desirably has an interconnect zone () on its upper surface. An IPD substrate () is bonded to the isolator substrate () so that TSVs () therein are coupled to the interconnect zone () on the isolator substrate () and/or TSVs () therein. The IPDs () are formed on its upper surface and coupled by TSVs () in the IPD () and isolator () substrates to devices () in the AD substrate (). The isolator substrate () provides superior IPD () to AD () cross-talk attenuation while permitting each substrate () to have small high aspect ratio TSVs (), facilitating high circuit packing density and efficient manufacturing.

Method And Apparatus For Forming A Borophosphosilicate Film

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US Patent:
20020090467, Jul 11, 2002
Filed:
Jan 9, 2002
Appl. No.:
10/043417
Inventors:
Chandrasekaram Ramiah - Phoenix AZ, US
Jeffrey Young - Los Gatos CA, US
Neil Pagel - Prescott AZ, US
Assignee:
Applied Materials, Inc. - Santa Clara CA
International Classification:
H05H001/24
US Classification:
427/569000
Abstract:
A method and apparatus for improving film stability and moisture resistance of a borophosphosilicate film. The BPSG film according to the present invention is formed under plasma conditions in which high and low frequency RF power is employed to generate the plasma. The high frequency power supply provides most of the energy to break the molecules in the process gas thereby forming the plasma and promoting the necessary reactions. The low frequency power supply regulates and controls ion bombardment of the BPSG film as it is formed. In a preferred embodiment, nitrogen is included in the process gas and the low frequency RF power supply is used to precisely control ion bombardment during deposition processing thereby allowing incorporation of an unexpectedly elevated amount of nitrogen into the film further improving film stability.
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