Browse Prior Art Database

Laser-Induced Mass Spectrometry With High Lateral Resolution

IP.com Disclosure Number: IPCOM000038756D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Briska, M: AUTHOR [+4]

Abstract

In a conventional Secondary Ion Mass Spectrometry (SIMS) system, ejected secondary particles 2 are ionized for analysis in mass detector 3. In the laser-induced SIMS, two symmetrically incident focussed beams 1a, 1b from a laser with a short pulse length provide additional ionization. A high lateral resolution of the SIMS signal in area 4, which is scanned by continuous primary ion beam 5, is obtained by correlating the output signal of mass detector 3 with the instantaneous position of the primary ion beam. Correlation may be effected by storing the detector signal together with the beam position signal in a computer. A laser with a narrow (e.g., tunable) frequency band can be used if resonant ionization of selected secondary particle species is desired to obtain high sensitivity and selectivity.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Laser-Induced Mass Spectrometry With High Lateral Resolution

In a conventional Secondary Ion Mass Spectrometry (SIMS) system, ejected secondary particles 2 are ionized for analysis in mass detector 3. In the laser- induced SIMS, two symmetrically incident focussed beams 1a, 1b from a laser with a short pulse length provide additional ionization. A high lateral resolution of the SIMS signal in area 4, which is scanned by continuous primary ion beam 5, is obtained by correlating the output signal of mass detector 3 with the instantaneous position of the primary ion beam. Correlation may be effected by storing the detector signal together with the beam position signal in a computer. A laser with a narrow (e.g., tunable) frequency band can be used if resonant ionization of selected secondary particle species is desired to obtain high sensitivity and selectivity. As the ionization volume in the cloud of secondary particles is relatively great, a strong detector signal is obtained in spite of the lateral resolution determined by the sharply focussed primary beam. The high lateral resolution of this system combined with the high inherent vertical resolution of SIMS renders it particularly suitable for the analysis of IC structures. The system avoids some of the problems of conventional SIMS, such as matrix effects and charge build- up.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]