Browse Prior Art Database

Registration of Electron Beam During Electron Beam Pattern Exposure

IP.com Disclosure Number: IPCOM000037009D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Brandis, EK: AUTHOR [+3]

Abstract

Disclosed is a method of registration of an electron beam (EB) when no surface topographic features are present.

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Registration of Electron Beam During Electron Beam Pattern Exposure

Disclosed is a method of registration of an electron beam (EB) when no surface topographic features are present.

In the original investigation 1, 2 of the EB registration problem, the registration signal was obtained by what is now called the EB-induced current (EBIC) technique, in which an induced signal is taken from a p-n junction diffused into the workpiece as the beam is scanned over the junction.

Reference 3 describes an eddy-current EBIC technique by which diffused regions in a silicon wafer can be delineated clearly without using electrical connection to the wafer.

The figure shows the application of a pulsed EB 1 to the upper surface of a silicon wafer 2 coated with photoresist or other planarizing material 3 while an oscillating current is induced into the silicon wafer by means of a tuned circuit 4 from below. The eddy- current loss in the region of the diffused junction alignment mark 5 determines the output signal, which is then processed with a lock-in amplifier before being displayed as an image or waveform.

To improve resolution, the region being probed could be the focus of a microwave beam projected from below, in place of the coil 4 sketched in the figure.

The beam energy must be high enough for the electrons to penetrate into the underlying regions, so that the edge sharpness of the resulting EBIC image will be degraded to a certain fraction of the electron penetration depth....