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Title: Method for photolithographic definition of recessed features on a semiconductor wafer utilizing auto-focusing alignment

Abstract

A method is disclosed for photolithographically defining device features up to the resolution limit of an auto-focusing projection stepper when the device features are to be formed in a wafer cavity at a depth exceeding the depth of focus of the stepper. The method uses a focusing cavity located in a die field at the position of a focusing light beam from the auto-focusing projection stepper, with the focusing cavity being of the same depth as one or more adjacent cavities wherein a semiconductor device is to be formed. The focusing cavity provides a bottom surface for referencing the focusing light beam and focusing the stepper at a predetermined depth below the surface of the wafer, whereat the device features are to be defined. As material layers are deposited in each device cavity to build up a semiconductor structure such as a microelectromechanical system (MEMS) device, the same material layers are deposited in the focusing cavity, raising the bottom surface and re-focusing the stepper for accurately defining additional device features in each succeeding material layer. The method is especially applicable for forming MEMS devices within a cavity or trench and integrating the MEMS devices with electronic circuitry fabricated on themore » wafer surface. 15 figs.« less

Inventors:
; ; ; ;
Issue Date:
Research Org.:
Sandia Corporation
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
672580
Patent Number(s):
5,783,340
Application Number:
PAN: 8-903,985
Assignee:
Sandia Corp., Albuquerque, NM (United States) SNL; SCA: 426000; PA: EDB-98:120785; SN: 98002024817
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Patent
Resource Relation:
Other Information: PBD: 21 Jul 1998
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; FABRICATION; SEMICONDUCTOR DEVICES; SCREEN PRINTING; MASKING; OPTICAL SYSTEMS; MICROELECTRONICS

Citation Formats

Farino, A.J., Montague, S., Sniegowski, J.J., Smith, J.H., and McWhorter, P.J. Method for photolithographic definition of recessed features on a semiconductor wafer utilizing auto-focusing alignment. United States: N. p., 1998. Web.
Farino, A.J., Montague, S., Sniegowski, J.J., Smith, J.H., & McWhorter, P.J. Method for photolithographic definition of recessed features on a semiconductor wafer utilizing auto-focusing alignment. United States.
Farino, A.J., Montague, S., Sniegowski, J.J., Smith, J.H., and McWhorter, P.J. Tue . "Method for photolithographic definition of recessed features on a semiconductor wafer utilizing auto-focusing alignment". United States.
@article{osti_672580,
title = {Method for photolithographic definition of recessed features on a semiconductor wafer utilizing auto-focusing alignment},
author = {Farino, A.J. and Montague, S. and Sniegowski, J.J. and Smith, J.H. and McWhorter, P.J.},
abstractNote = {A method is disclosed for photolithographically defining device features up to the resolution limit of an auto-focusing projection stepper when the device features are to be formed in a wafer cavity at a depth exceeding the depth of focus of the stepper. The method uses a focusing cavity located in a die field at the position of a focusing light beam from the auto-focusing projection stepper, with the focusing cavity being of the same depth as one or more adjacent cavities wherein a semiconductor device is to be formed. The focusing cavity provides a bottom surface for referencing the focusing light beam and focusing the stepper at a predetermined depth below the surface of the wafer, whereat the device features are to be defined. As material layers are deposited in each device cavity to build up a semiconductor structure such as a microelectromechanical system (MEMS) device, the same material layers are deposited in the focusing cavity, raising the bottom surface and re-focusing the stepper for accurately defining additional device features in each succeeding material layer. The method is especially applicable for forming MEMS devices within a cavity or trench and integrating the MEMS devices with electronic circuitry fabricated on the wafer surface. 15 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {7}
}