Browse Prior Art Database

Blind Electrical Probing in a Scanning Electron Microscope

IP.com Disclosure Number: IPCOM000051580D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 39K

Publishing Venue

IBM

Related People

Schick, JD: AUTHOR

Abstract

To perform electron beam induced current (EBIC) and voltage contrast (VC) measurements in a scanning electron microscope (SEM), electrical contact to the device is required. Using the disclosed technique contact can be made on the device with control outside the chamber, resulting in versatility, precision, time savings.

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Blind Electrical Probing in a Scanning Electron Microscope

To perform electron beam induced current (EBIC) and voltage contrast (VC) measurements in a scanning electron microscope (SEM), electrical contact to the device is required. Using the disclosed technique contact can be made on the device with control outside the chamber, resulting in versatility, precision, time savings.

Usual electrical probing of an integrated circuit or test device is accomplished on an optical microscope stage. The device pad is viewed through the optical microscope, and the probe is manually lowered to the pad. Physical contact between the probe and the pad is noted when the probe seems to slide ahead while lowering. The lack of a three-dimensional view of the probing operation makes very fine probing difficult.

In order to make EBIC measurements and VC measurements in a SEM, electrical contact must be made to the device. This is often done by wire bonding or placing a fixed probe sample in the SEM chamber. There is no possibility of changing the device probing while the device is in the chamber.

Described here is a technique for probing in the SEM and for blind probing in the SEM while viewing another area of the device. In the SEM, the pad to be probed is viewed using the electrooptical image. This gives a good depth-of-field view of the pad so that very fine probing of small pads or devices can be accomplished. The SEM image is a "three-dimensional-like" image, with good resolution. Then, in order to perform the desired EBIC or VC measurement, the specimen must be moved; the device of interest may then be viewed on the electrooptical CRT. In order to move the device with the probe in place, the probing fixture would have to be mounted on the sample stage. Most specimen stages could not accommodate such a cumbersome fix...