Moisture detection and ingression monitoring systems and methods of manufacture

Patent metadata

Field	Value
Publication number	US-10126260-B2
Application number	US-201514706322-A
Country	US
Kind code	B2
Filing date	May 7, 2015
Priority date	May 7, 2015
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

Moisture detection and ingression monitoring systems and methods of manufacture are provided. The moisture detection structure includes chip edge sealing structures including at least one electrode forming a capacitor structured to detect moisture ingress within an integrated circuit. The at least one electrode and a second electrode of the capacitor is biased to ground and to a moisture detection circuit.

First claim

What is claimed:

1. A moisture detection structure comprising chip edge sealing structures comprising a guardring structure and a crackstop structure both of which are formed from metal features extending vertically through multiple wiring and insulator layers along an edge of the chip and at least one electrode electrically connected to the metal features of either the guardring structure or the crackstop structure, and further comprising a second electrode which forms a capacitor with the first electrode, the capacitor structured to detect moisture ingress within an integrated circuit, wherein the at least one electrode and the second electrode of the capacitor is biased to ground and to a moisture detection circuit.

2. The structure of claim 1 , wherein:
the chip edge sealing structures comprise the guardring structure with the at least one electrode and the second electrode; and
the at least one electrode is biased to ground and the second electrode is electrically connected to the moisture detection circuit.

3. The structure of claim 2 , wherein the moisture detection circuit detects a difference in capacitance of the capacitor corresponding to moisture ingress into the integrated circuit.

4. The structure of claim 1 , wherein the chip edge sealing structures comprises the guardring ring structure with the one electrode extending from a predetermined wiring layer and the second electrode forming the capacitor is one of a solder bump or ball limiting metallurgy.

5. The structure of claim 4 , wherein either of the one electrode and the second electrode is biased to ground and the other of the one electrode and the second electrode is electrically connected to the moisture detection circuit.

6. The structure of claim 1 , wherein the chip edge sealing structures comprise the crackstop structure with the one electrode extending from a predetermined wiring layer and further comprising the second electrode which is separated therefrom by a gap provided between the one electrode and the second electrode.

7. The structure of claim 6 , wherein either of the one electrode and the second electrode is biased to ground and the other of the one electrode and the second electrode is electrically connected to the moisture detection circuit.

8. The structure of claim 1 , wherein the chip edge sealing structures comprise the crackstop structure with the one electrode extending from a predetermined wiring layer and further comprising the second electrode extending from a capacitor plate, which is separated therefrom by a gap provided between the one electrode and the second electrode.

9. The structure of claim 8 , wherein either of the one electrode and the second electrode is biased to ground and the other of the one electrode and the second electrode is electrically connected to the moisture detection circuit.

10. The structure of claim 1 , wherein the capacitor is structured to provide moisture sensing capability for real-time 360 degree on chip moisture detection.

11. A moisture detection structure comprising at least one metal guardring or crackstop structure surrounding one or more devices of an integrated circuit, the at least one metal guardring or crackstop structure extending through a plurality of metal wiring layers connected together with via interconnects at an edge of the integrated circuit, at least one electrode formed from a same material as the metal wiring layers and which is in direct electrical contact to one of the metal wiring layers at a metal wiring layer, and a second electrode which forms a capacitor with the first electrode and which is structured to detect moisture ingress, the second electrode is electrically connected to a moisture detection circuit.

12. The structure of claim 11 , further comprising a moisture detection circuit electrically connected to one of the first electrode and the second electrode.

13. The structure of claim 12 , wherein the moisture detection circuit comprises a threshold voltage value which triggers an alarm when a measured voltage value, Vc, falls below the threshold voltage value.

14. The structure of claim 13 , wherein either of the first electrode and the second electrode is biased to ground and the other of the first electrode and the second electrode is electrically connected to the moisture detection circuit.

15. The structure of claim 11 , wherein the at least one metal guardring or crackstop structure which includes the first electrode and the second electrode is a solder bump or ball limiting metallurgy.

16. The structure of claim 11 , wherein the at least one metal guardring or crackstop structure which includes the first electrode and the second electrode extends from a capacitor plate.

17. The structure of claim 11 , wherein the at least one metal guardring or crackstop structure which includes the first electrode extending from a predetermined wiring layer and the second is separated therefrom by a gap provided between the first electrode and the second electrode.

18. The structure of claim 11 , wherein the capacitor is structured to provide moisture sensing capability for real-time 360 degree on chip moisture detection.

19. The structure of claim 11 , wherein the at least one metal structure completely surrounds the one or more devices of the integrated circuit thereby providing chip moisture detection and moisture ingression monitoring both vertically and horizontally at any metal levels, in 360 degrees.

20. A method, comprising:
at an initial power up of an integrated circuit:
measuring a voltage value, Vc, and further including:
turning on an NFET type gate with a positive pulse and discharging a capacitor completely;
turning on a PFET type gate with a negative pulse and charging the capacitor with a current for a first time period, and
sampling the voltage value, Vc;

turning on a transmission gate and an analog to digital converter with two separate signals during the first time of the power on;
converting the measured value to an initial digital value, Vc; and
saving the measured value as an initial value;
converting the initial digital value to a threshold analog voltage of a voltage comparator for real time moisture detection through a voltage divider, which provides a margin for voltage comparison; and

during operation of the integrated circuit:
measuring the voltage value, Vc, comprising:
turning on the NFET type gate with the positive pulse and discharging the capacitor completely;
turning on the PFET type gate with a negative pulse of pulse width T and charging the capacitor with the input current for the pulse width T;

if the value of Vc is higher than the threshold analog voltage which is the converted value of Vc at initial power up, then an output is at logic high indicating operation of the integrated circuit; and
if the value of Vc is lower than the threshold analog voltage, the output is at the logic low and a latch is triggered and an alarm is sent indicating that there is moisture in the integrated circuit.

Assignees

• IBM

Inventors

• Chen Fen
• Gambino Jeffrey P
• Graas Carole D
• Liu Wen
• Periasamy Prakash

Classifications

• G01N27/223 Primary

  for determining moisture content, e.g. humidity (rain detectors on vehicle windows B60S1/0825) · CPC title

• G01R27/2605

  Measuring capacitance (capacitive sensors G01D5/24) · CPC title

• H03K17/955

  using a capacitive detector · CPC title

• G01D5/24

  by varying capacitance · CPC title

• G01D5/2405

  by varying dielectric · CPC title