Browse Prior Art Database

Low Charging Conformal Phosphorous Silicon Glass Passivation Process

IP.com Disclosure Number: IPCOM000115842D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Lasky, JB: AUTHOR [+3]

Abstract

To make a passivation layer between gate conductors and a first metal wiring level, a three layer plasma enhanced chemical vapor deposition (PECVD) process provides high device yield and high throughput using commercially available tools. Optimization of process parameters for low compressive stress, good step coverage, and low charging contributes to high device yield and reliability.

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Low Charging Conformal Phosphorous Silicon Glass Passivation Process

      To make a passivation layer between gate conductors and a first
metal wiring level, a three layer plasma enhanced chemical vapor
deposition (PECVD) process provides high device yield and high
throughput using commercially available tools.  Optimization of
process parameters for low compressive stress, good step coverage,
and low charging contributes to high device yield and reliability.

      The new process is comprised of three layers: 1) phosphorous
doped glass (PSG), 2) undoped silicon glass (USG), and 3) a second
layer of PSG.  Both the PSG and USG deposition processes are
basically well-known Tetra Ethyl Oxy-Silane (TEOS) PECVD processes
performed in commercial cluster tools.

Process variables are selected to produce film layers:
  o  having a low level of compressive stress to maintain film
      adhesion and film integrity through subsequent process thermal
      cycles.
  o  with optimal gap-fill at steep topology changes to minimize
      voids.
  o  with low charging during deposition to avoid discharges from
      electrically floating conductors through insulators, e.g., gate
      dielectric layers.
  o  with minimal sputter etchback to reduce processing time while
      providing good coverage and gap-fill.

      To achieve the previously discussed film properties, USG
processing is held within the limits shown for parameters identi...