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Magnetic Guiding Fields in an Electron Spectrometer for Laser-Testing

IP.com Disclosure Number: IPCOM000038336D
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 3 page(s) / 38K

Publishing Venue

IBM

Related People

Beha, JG: AUTHOR [+4]

Abstract

This article suggests a method for integrated circuit chip testing using laser-excited photoemission. The photoelectrons emitted from the tested structure are deflected by a homogeneous magnetic field in a semicircular path to a detector which is arranged at the side of the chip. If necessary, an electrostatic focussing field is additionally provided for focussing the electrons on the desired detector target. A laser testing scheme has been proposed which allows testing of the dynamic operation and performance of high-speed VLSI circuits, including on-chip, contactless measurement of AC switching waveforms (picosecond time scales). This technique achieves high time, lateral, and voltage resolution.

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Magnetic Guiding Fields in an Electron Spectrometer for Laser-Testing

This article suggests a method for integrated circuit chip testing using laser- excited photoemission. The photoelectrons emitted from the tested structure are deflected by a homogeneous magnetic field in a semicircular path to a detector which is arranged at the side of the chip. If necessary, an electrostatic focussing field is additionally provided for focussing the electrons on the desired detector target. A laser testing scheme has been proposed which allows testing of the dynamic operation and performance of high-speed VLSI circuits, including on- chip, contactless measurement of AC switching waveforms (picosecond time scales). This technique achieves high time, lateral, and voltage resolution. One problem connected with the voltage resolution is the existence of microfields in the environment of a measuring point of a real VLSI chip. The reduction of this problem to a negligible disturbance should be done by installing an extraction grid or an immersion lens directly above the chip. For the subsequent energy analysis of the extracted electrons a second retarding grid is needed. The changes in these retarding field spectra provide the information about the voltages applied to the chip. The most simple approach is to install the retarding grid and the extraction grid both directly above the chip. This means that the incoming laser beam has to transmit through both grids before it reaches the chip. The disadvantage of this approach is the disturbance of the laser beam. The effect of the extraction grid may be small, except a probable diffraction at the grid which will act like a Fresnel lens for the light beam. But the additional retarding grid in the path of the laser beam together with the extraction grid is expected to cause a considerable reduction in the optical transmission for the laser beam and therefore will reduce the intensity of the incident laser beam. Therefore, it is important to avoid at least the installation of two grids in the path of the laser beam, and it would be even better to avoid totally the existence of grids in the laser beam. One method to avoid having the retarding grid in the path of...