In-tool ESD events monitoring method and apparatus

• US 9,671,448 B2
• Filed: 12/26/2013
• Issued: 06/06/2017
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Nelsen, Lyle D., Heymann, Steven B., Hogsett, Mark E.
• Primary Examiner(s): Vazquez, Arleen M
• Assistant Examiner(s): YENINAS, STEVEN LEE
• Application Number:
  US14/140,860
• Publication Number:
  US 20140184253A1
• Time in Patent Office: 1,258 Days
• Field of Search: 32420716, 324509, 324457, 324458, 324227, 324 7613, 324 7616, 324 95, 324102, 32475002, 324382, 324 725, 324 72, 324452, 324456, 324 45, 361112, 361113, 361 91, 340600, 340635, 340657, 340649
• CPC Class Codes: G01R 31/001 Measuring interference from external sources to, or emission from, the device under test, e.g. EMC, EMI, EMP or ESD testing measuring electromagnetic fields G01R29/08; circuits for generating HV pulses in dielectric strength testing G01R31/14
• CPC Class Codes: G01R 31/002 where the device under test is an electronic circuit
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence

Abstract

In one embodiment of the invention, an apparatus for electrostatic discharges (ESD) events monitoring incorporating a charged device model event simulator (CDMES) unit comprises: at least one antenna positioned in a process area; an ESD detector coupled to said at least one antenna; said ESD detector wirelessly coupled to said CDMES unit; and said ESD detector calibrated for different discharge energies generated by said CDMES unit.

Claims

1. An apparatus for electrostatic discharge (ESD) events monitoring incorporating a charged device model event simulator (CDMES) unit, the apparatus comprising:

an ESD detector coupled to at least one antenna;

said ESD detector wirelessly coupled to said CDMES unit; and

said ESD detector calibrated for different discharge energies generated by said CDMES unit;

wherein said ESD detector is configured to compare an adjustable threshold voltage level with a signal amplitude of an ESD radiant pulse that is received by said at least one antenna;

wherein said ESD detector is configured to determine if a pulse duration of said ESD radiant pulse is within upper and lower time interval boundaries of an ESD event when said signal amplitude of said ESD radiant pulse exceeds said adjustable threshold voltage level; and

wherein said ESD detector is configured to generate a signal indicating an EMI (electro-magnetic interference or emission) that is a valid ESD-type event when said pulse duration of said ESD radiant pulse is within said upper and lower time interval boundaries, wherein said ESD detector comprises;

a first circuit configured to, in response to the signal amplitude of the ESD radiant pulse exceeding the adjustable threshold voltage level, output a second signal for a time duration corresponding to the upper time interval boundary of the ESD event, the second signal representative of said signal amplitude of said ESD radiant pulse exceeding said adjustable threshold voltage level; and

a second circuit configured to output a third signal only when the signal amplitude of the ESD radiant pulse returns below the adjustable threshold voltage level while the first circuit is outputting the second signal during the time duration, the third signal representative of the ESD radiant pulse exceeding the adjustable threshold voltage level and the ESD radiant pulse being within said time interval boundaries.

2. The apparatus of claim 1, wherein:

said at least one antenna comprises a first antenna coupled to said ESD detector and a second antenna coupled to said ESD detector; and

said first antenna is positioned in a first process area and said second antenna is positioned in a second process area.

3. The apparatus of claim 2, wherein said first process area is separated from said second process area and wherein said first antenna and second antenna form multi-channels.

4. The apparatus of claim 2, wherein said first antenna and second antenna are similar in an antenna response sensitivity.

5. The apparatus of claim 2, where said first antenna and second antenna are different in antenna response sensitivities.

6. The apparatus of claim 2, wherein the first process area comprises a tool process area having a socket configured to receive a semiconductor chip and an external processing area, wherein the external processing area is external to the tool process area and is separated from the tool process area by a distance, and wherein another antenna is positioned in the external processing area and is coupled to said ESD detector.

7. The apparatus of claim 2, wherein the first process area comprises at least one socket configured to receive at least one semiconductor chip.

8. The apparatus of claim 1, wherein the ESD detector comprises a circuit that is configured to detect radiated pulse electromagnetic signals, configured to discriminate between different pulse event types, and configured to register a charged device model (CDM) event when the CDM event is above a calibrated threshold.

9. The apparatus of claim 1, wherein the ESD detector is configured to discriminate between different pulse event types based on an adjustable pulse event threshold.

10. The apparatus of claim 1, wherein the ESD detector comprises a circuit that is configured to use a two-dimensional algorithm by analyzing EMI (electromagnetic interference) events in a time domain and performing threshold discrimination to detect pulse electrostatic discharge of a certain electromagnetic energy.

11. The apparatus of claim 8, wherein the ESD detector is calibrated for a specific device withstand voltage threshold based on one or more simulations of the CDM event.

12. The apparatus of claim 1, wherein said at least one antenna comprises:

a micro antenna coupled to the ESD detector;

wherein the micro antenna comprises antenna gain characteristics for optimal detection at specified ranges while excluding undesired signal sources.

13. The apparatus of claim 1, wherein said ESD detector is configured to send said ESD radiant pulse to an alarm output driver in order to permit the alarm output driver to send an output event occurrence signal to a tool or computer or configured to send said ESD radiant pulse to an audio or visual indicator.

14. A method for electrostatic discharge (ESD) events monitoring incorporating a charged device model event simulator (CDMES) unit, the method comprising:

calibrating an ESD detector for different discharge energies;

detecting one of the discharge energies via at least one antenna and the ESD detector; and

comparing an adjustable threshold voltage level with a signal amplitude of an ESD radiant pulse that is received by said a least one antenna;

determining if a pulse duration of said ESD radiant pulse is within upper and lower time interval boundaries of an ESD event by, in response to the signal amplitude of the ESD radiant pulse exceeding the adjustable threshold voltage level, outputting a second signal for a time duration corresponding to the upper time interval boundary of the ESD event, the second signal representative of said signal amplitude of said ESD radiant pulse exceeding said adjustable threshold voltage level; and

generating a third signal indicating an EMI (electro-magnetic interference or emission) that is a valid ESD-type event only when the signal amplitude of the ESD radiant pulse returns below the adjustable threshold voltage level while the second signal is being output during the time duration, the third signal representative of the ESD radiant pulse exceeding the adjustable threshold voltage level and the ESD radiant pulse being within said time interval boundaries.

15. The method of claim 14, wherein said detecting comprises:

discriminating between different pulse event types based on an adjustable pulse event threshold.

16. The method of claim 14, wherein said detecting comprises:

using a two-dimensional algorithm by analyzing EMI (electro-magnetic interference) events in a time domain and performing threshold discrimination to detect pulse electrostatic discharge of certain electromagnetic energy.

17. The method of claim 14, further comprising:

setting antenna gain characteristics for optimal detection at specified ranges while excluding undesired signal sources.

18. The method of claim 14, wherein said CDMES unit is configured for in situ calibration, and wherein said CDMES unit comprises a collapsing capacitor.

19. The method of claim 14,

wherein said detecting said discharge energies comprises:

detecting radiated pulse electromagnetic signals; and

wherein said calibrating comprises;

discriminating between different pulse event types, and registering a charged device model (CDM) event when the CDM event is above a calibrated threshold.