Methods and apparatus for detection of gaseous corrosive contaminants

Patent metadata

Field	Value
Publication number	US-9575040-B2
Application number	US-201414265623-A
Country	US
Kind code	B2
Filing date	Apr 30, 2014
Priority date	Jan 10, 2011
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

A corrosion sensor includes a plurality of metal strips having different thicknesses. A first metal strip with the least thickness is first employed to provide sensitive corrosion detection. After an exposed portion of the first metal strip is consumed, a second metal strip having a second least thickness can be employed to provide continued sensitive corrosion detection employing a remaining un-corroded portion of the second metal strip. The plurality of metal strips can be sequentially employed as exposed portions of thinner metal strips become unusable through complete corrosion and un-corroded exposed portions of thicker metal strips become thin enough to provide sensitive corrosion detection.

First claim

What is claimed is:

1. A method for detecting a corrosion-accelerating gas at a location, the method comprising:
providing a corrosion detection apparatus comprising:
a plurality of metal strips located on an insulating surface of a substrate, wherein each of the plurality of metal strips has a different thickness in a direction substantially perpendicular to the insulating surface of the substrate than another of the plurality of metal strips,
wherein each of the plurality of metal strips is comprised of:
an exposed strip portion that is permeable to the corrosion-accelerating gas; and
a protected strip portion that is not permeable to the corrosion-accelerating gas,
wherein the exposed strip portion and the protected strip portion of the each of the plurality of metal strips are connected in a series connection;

measuring data on a resistance change in a first metal strip of the plurality of metal strips, the first metal strip being exposed to the corrosion-accelerating gas in a first time period;
determining a first corrosion rate of the first metal strip for the first time period based on the measured data on the resistance change in the first metal strip;
measuring data on a resistance change in a second metal strip of the plurality of metal strips, the second metal strip being exposed to the corrosion-accelerating gas in the second time period; and
determining a second corrosion rate of the second metal strip in the second time period based on the measured data on the resistance change in the second metal strip,
wherein:
the first metal strip has a first thickness in the direction substantially perpendicular to the insulating surface, the second metal strip has a second thickness in the direction substantially perpendicular to the insulating surface, and the second thickness is greater than the first thickness, and
the second time period includes at least a time period subsequent to the first time period.

2. The method according to claim 1 , further comprising:
determining that the measured data on the resistance change in the first metal strip is not linear to an exposure time of the first metal strip to the corrosion-accelerating gas,
wherein the second time period is commenced upon determination that the measured data on the resistance change in the first metal strip is not linear to the exposure time of the first metal strip to the corrosion-accelerating gas.

3. The method according to claim 1 , wherein the step of measuring the data on the resistance change in the first metal strip and the step of measuring the data on the resistance change in the second metal strip are performed simultaneously before the first metal strip becomes electrically open.

4. The method according to claim 1 ,
wherein the step of measuring the data on the resistance change in the first metal strip comprises:
applying electrical current through the exposed strip portion and the protected strip portion of the first metal strip;
measuring a first voltage difference across the exposed strip portion of the first metal strip; and
measuring a second voltage difference across the protected strip portion of the first metal strip,

wherein step of determining the first corrosion rate comprises determining the first corrosion rate based on a ratio of the second voltage difference across the exposed strip portion of the first metal strip to the first voltage difference across the exposed strip portion of the first metal strip, and a thickness of the protected strip portion of the first metal strip,
wherein the step of measuring the data on the resistance change in the second metal strip comprises:
applying electrical current through the exposed strip portion and the protected strip portion of the second metal strip;
measuring a first voltage difference across the exposed strip portion of the second metal strip; and
measuring a second voltage difference across the protected strip portion of the second metal strip,

wherein the step of determining the second corrosion rate comprises determining the second corrosion rate based on a ratio of the second voltage difference across the exposed strip portion of the second metal strip to the first voltage difference across the exposed strip portion of the second metal strip, and a thickness of the protected strip portion of the second metal strip.

5. The method according to claim 1 , further comprising:
sequentially determining whether at least one metal strip among the plurality of metal strips is electrically open in an order of increasing thickness in the direction substantially perpendicular the insulating surface beginning with a metal strip having a least thickness;
measuring data on a resistance change in a metal strip that is not electrically open; and
determining a corrosion rate of the metal strip that is not electrically open.

6. The method according to claim 1 , wherein in the step of providing the corrosion detection apparatus, the plurality of metal strips are provided such that the different thickness of the plurality of metal strips are integer multiples of a minimum thickness among the different thicknesses.

7. The method according to claim 6 , further comprising exposing all exposed strip portions to the corrosion-accelerating gas at the same time.

8. The method according to claim 1 , wherein in the step of providing the corrosion detection apparatus, the plurality of metal strips are provided such that differences in thickness of the plurality of metal strips are integer multiples of a difference between a pair of metal strips among the plurality of metal strips.

9. The method according to claim 1 , wherein in the step of providing the corrosion detection apparatus, each metal strip among the plurality of metal strips is provided with a substantially constant width in a direction substantially parallel to the insulating surface.

10. The method according to claim 1 , wherein in the step of providing the corrosion detection apparatus and prior to measuring data on a resistance change in one or more of the plurality of metal strips, the plurality of metal strips are provided such that within each metal strip, the exposed strip portion and the protected strip portion have a same resistance.

11. The method according to claim 1 , wherein in the step of providing the corrosion detection apparatus and prior to measuring data on a resistance change in one or more of the plurality of metal strips, the plurality of metal strips are provided such that within each metal strip, the exposed strip portion and the protected strip portion have a substantially same width in a direction substantially parallel to the insulating surface, wherein the substantially same width is greater than ten times the thickness of the each metal strip.

12. The method according to claim 1 , wherein in the step of providing the corrosion detection apparatus and prior to measuring data on a resistance change in one or more of the plurality of metal strips, the plurality of metal strips are provided such that within each metal strip, the exposed strip portion and the protected strip portion have a substantially same length in a direction substantially parallel to the insulating surface, wherein the substantially same length is greater than one hundred times the thickness of the each metal strip.

13. The method according to claim 1 , wherein the step of measuring the data on the resistance change in the first metal strip comprises:
arranging a current source to provide electrical current through the exposed strip portion and the protected strip portion of the first metal strip;
arranging a first voltmeter to measure a voltage diff

Assignees

• IBM
• Globalfoundries Inc

Inventors

• Chey S Jay
• Hamann Hendrik F
• Klein Levente I
• Schappert Michael A
• Singh Prabjit

Classifications

• G01N17/046 Primary

  Means for supporting or introducing coupons · CPC title

• G01N33/0027 Primary

  concerning the detector · CPC title

• G01N27/04

  by investigating resistance · CPC title

• H05K2201/09736

  Varying thickness of a single conductor; Conductors in the same plane having different thicknesses · CPC title

• Y10T29/49124

  On flat or curved insulated base, e.g., printed circuit, etc. · CPC title