Apparatus for use with analytical measuring instruments using electromagnetic radiation analysis methods

• US 5,350,923 A
• Filed: 12/23/1992
• Issued: 09/27/1994
• Est. Priority Date: 02/06/1992
• Status: Expired due to Fees

• Current Assignee: Nortel Networks UK Limited (Nortel Networks Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Kovats, Tibor F. I., Bassignana, Isabella C.
• Primary Examiner(s): Dzierzynski, Paul M.
• Assistant Examiner(s): NGUYEN, KIET TUAN
• Application Number:
  US07/996,411
• Time in Patent Office: 643 Days
• Field of Search: 250/453.11, 378/161, 378/70, 378/79, 378/80, 356/244
• US Class Current: 250/453.11
• CPC Class Codes: G01N 23/20025 Sample holders or supports therefor

Abstract

A method and apparatus for use in performing non-contact analytical evaluation of a semiconductor wafer, which needs to be kept clean, to be performed outside of clean room facilities. The apparatus maintains a clean environment surrounding the semiconductor wafer and a portion of the apparatus is substantially transparent to a probe beam of electromagnetic radiation such as X-rays and visible light. The invention substantially overcomes the expenses associated with locating analytical test equipment for testing semi-conductor wafers within clean room facilities.

Claims

1. An apparatus for use in performing non contact analytical evaluation of a semiconductor wafer, comprising a sealable container having wall means defining a chamber, which upon sealing the container is then isolated;

the sealable container also comprising;

window means into the sealable container, the window means comprising a planar membrane composed solely of a substantially non-crystalline organic polymer, the window means being capable of allowing a probe beam of radiant energy of wavelengths corresponding to X-ray, visible light, or ultra-violet light frequency bands, suitable for non contact analytical evaluation of the semiconductor wafer to pass therethrough into the isolated chamber while non-substantially affecting diffraction and attentuation of the beam and which is capable of passing radiant energy outwardly from the isolated chamber while non-substantially affecting the diffraction and attenuation of the radiant energy;

releasable securing means to secure the window means to the wall means and over an opening to the chamber and to enable removal of the window means to allow for insertion of a wafer through the opening and into the chamber;

sealing means to seal the window means to the wall means when the window means is secured to the wall means; and

positioning means for positioning the semiconductor wafer within the isolated chamber in a location aligned with the window means to allow the probe beam of radiant energy to be directed through the window means at the semiconductor wafer and to allow radiant energy to pass outwardly from the semiconductor wafer within the chamber.

2. An apparatus according to claim 1, wherein the sealable container is composed of a charge conducting material.

3. An apparatus according to claim 1 wherein the window means comprises a single window, the window comprising a membrane having a surface area which is larger than the area on the wafer surface which is to be tested.

4. An apparatus according to claim 1 wherein the window means comprises a single window, the window comprising a membrane having a surface area which is larger than the area on the wafer surface which is to be tested.

5. An apparatus according to claim 1 wherein the membrane is capable of passing infra-red light.

6. A method of evaluating a semiconductor wafer by non contact analytical evaluation, comprising the steps of:

in a first environment, inserting the semiconductor wafer into a chamber within and defined by walls of an open container and positioning the semiconductor wafer in a location within the chamber, the container capable of being selected to isolate the chamber from an outside environment, the container having window means into the chamber, the window means comprising a planar membrane composed solely of a substantially noncrystalline organic polymer, the window means being capable of allowing a probe beam of radiant energy of wavelengths corresponding to X-ray, visible light, or ultra-violet light frequency bands, suitable for non contact analytical evaluation of the wafer, to pass there through while non-substantially affecting diffraction and attenuation of the beam, and which is capable of passing radiant energy outwardly from the isolated chamber while non-substantially affecting diffraction and attenuation of the radiant energy;

sealing the container to isolate the chamber and the semiconductor wafer from the first environment with the semiconductor wafer aligned with the window means to enable the probe beam of radiant energy to be directed through the window means and at the semiconductor wafer;

moving the sealed container into a second environment and with the chamber and semiconductor wafer isolated form the second environment;

passing the probe beam of radiant energy through the window means at the semiconductor wafer during the performance of the non contact analytical evaluation; and

analyzing radiant energy from the semiconductor wafer which passes outwardly from the wafer within the chamber through the window means to determine structural characteristics about the semiconductor wafer.

7. A method according to claim 6 wherein the window means comprises a single window comprising a membrane having a surface area which is larger than the area of the wafer surface to be tested to expose any part of the wafer to the beam when directed towards the wafer at an angle of less than normal to the wafer surface, the method comprising directing the beam successively from localised position to localised position of the wafer surface and analyzing radiant energy from the wafer at each localized position.

8. An apparatus for use in performing non contact analytical evaluation of a semiconductor wafer, comprising a sealable container having wall means defining la chamber, which upon sealing the container is then isolated;

the sealable container also comprising;

window means into the sealable container, the window means comprising a membrane of nitrocellulose polymer having a thickness of approximately 3.0 microns, the window means being thereby capable of allowing a probe beam of radiant energy of wavelengths corresponding to X-ray, visible light, or ultra-violent light frequency bands, suitable for non contact analytical evaluation of the semiconductor wafer to pass therethrough into the isolated chamber while non-substantially affecting diffraction and attenuation of the beam and which is capable of passing radiant energy outwardly from the isolated chamber while non-substantially affecting the diffraction and attenuation of the radiant energy; and

positioning means for positioning the semiconductor wafer within the isolated chamber in a location aligned with the window means to allow the probe beam of radiant energy to be directed through the window means at the semiconductor wafer and to allow radiant energy to pass outwardly from the semiconductor wafer within the chamber.

9. An apparatus for use in performing non contact analytical evaluation of a semiconductor wafer, comprising a sealable container having wall means defining a chamber, which upon sealing the container is then isolated;

the sealable container also comprising;

window means into the sealable container, the window means comprising a planar membrane composed solely of a substantially non-crystalline organic polymer, the window means being capable of allowing a probe beam of radiant energy suitable for non contact analytical evaluation of the semiconductor wafer to pass therethrough into the isolated chamber while non-substantially affecting diffraction and attenuation of the beam and which is capable of passing radiant energy outwardly from the isolated chamber while non-substantially affecting the diffraction and attenuation of the radiant energy; and

positioning means for positioning the semiconductor wafer within the isolated chamber in a location aligned with the window means to allow the probe beam of radiant energy to be directed through the window means at the semiconductor wafer and to allow radiant energy to pass outwardly from the semiconductor wafer within the chamber.