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Browse Prior Art Database

Preparation Method for Electrically Probing Submicron Devices

IP.com Disclosure Number: IPCOM000115693D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Coutu, PT: AUTHOR [+3]

Abstract

Appropriately-spaced contact pads are made and connected to very closely spaced device contacts using a commercially available focused ion beam instrument for most steps in the process. The technique is used for electrical device testing in failure analysis.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 86% of the total text.

Preparation Method for Electrically Probing Submicron Devices

      Appropriately-spaced contact pads are made and connected to
very closely spaced device contacts using a commercially available
focused ion beam instrument for most steps in the process.  The
technique is used for electrical device testing in failure analysis.

      Referring to Fig. 1, semiconductor device 2, having contacts 4
exposed at the device surface which are too closely spaced to contact
independently with pressure probes.  To delineate an area of device
surface containing the device contacts 4, positive photoresist 6 is
deposited and dried.  The area of interest is exposed to light under
a light microscope and developed, thereby uncovering the surface of
the device only in the area of interest.  The device and remaining
photoresist is then baked at 95ºC for an hour.

      Referring to Fig. 2, the device is coated with an insulator 8
(e.g., SiO2) by dielectric sputtering.

      The remaining operations all may be accomplished in a
commercially available Focused Ion Beam (FIB) tool.  Contact holes
(vias) 10 are ion beam milled through insulator 8 as shown in Fig. 3.

      Referring to Fig. 4, conductive probe pads 12 and through-via
connective material 14 is deposited.  A hard, relatively good
conductor, e.g., tungsten (W) is preferred for regions 12 and 14.
Finally, pads 12 and 14 are interconnected by FIB straps 16, which
may also be of W.

      Probe pads 12 are...