JPS63271949A - Method of semiconductor analysis - Google Patents

Abstract

PURPOSE:To improve on precision in a band-structure analysis by a method wherein a scanning electron microscope is used to analyze the energy of secondary electrons emitted by a specimen for the acquisition of a plasmon energy loss signal image. CONSTITUTION:In an environmental chamber 9, an electron beam 3 is projected by an electron gun 8 upon a specimen 2 that is for example a semiconductor wafer. Secondary electrons 4 emitted by the specimen 2 are examined in an electron energy analyzer 1. A specific plasmon loss signal 5 is collected reflecting the loss of a secondary electron spectrum in its energy-differentiated mode. Synchronism is established with the current in a deflecting coil 7 for the formation of a plasmon energy loss image on the screen of a CRT tube 6. In this way, high-precision analysis is accomplished of a band structure such as the doping profile of the semiconductor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to semiconductor analysis methods such as fine doping profile analysis of semiconductors using electron beams.

2. Description of the Related Art Conventionally, analysis of band structures such as doping profiles of semiconductors has been carried out by observing differences in etching.

Problems to be Solved by the Invention The difference in etching depending on the doping of the semiconductor depends on the etching conditions, and sufficient precision cannot be obtained. In view of this point, the present invention is intended to accurately analyze the band structure such as the doping profile of a semiconductor without using etching.

Means for Solving the Problems The method of the present invention analyzes the energy of secondary electrons emitted from a sample using a running electron microscope using an electron beam to obtain a plasmon energy loss signal image. Second, it is designed to analyze the fine band structure of semiconductor devices.

Since the energy of the active plasmon is proportional to the square root of the conduction electron density, the conduction electron density distribution or band structure at each location in the sample can be determined from the plasmon loss signal distribution image.

Embodiment FIG. 1 shows an embodiment of the present invention applied to a scanning electron microscope apparatus. In the environmental chamber 9, an electron beam 3 is incident on a sample 2 such as a semiconductor wafer using an electron gun 8, and the energy of the secondary electrons 4 emitted from the sample is analyzed by an electron energy analyzer 1. Next, a specific plasmon loss signal 6 in the electron spectrum is generated, and a plasmon energy loss image is formed on the screen of the cathode ray tube 6 in synchronization with the current of the deflection coil 7.

Figures 2a and b each show different points 1 o on the sample.
, 20 schematically shows a measurement example of the plasmon loss spectrum in the energy differential mode. In FIG. 2, the vertical axis shows the respective intensities, and the horizontal axis shows the energy loss value. The energy loss values in FIGS. 2(a) and (b) are different, reflecting the electron density at a point 10°20 on the sample. When the detected energy value of the electron energy analyzer is set to the plasmon loss peak at point 1o as shown in Fig. 2, point 10 corresponding to Fig. 2 (,) becomes bright, and point 2o corresponding to b becomes dark. . FIG. 3 schematically shows a figure (plasmon loss signal line 10o) displayed on a cathode ray tube composed of bright points measured in this way, superimposed on a normal secondary electron image 200 shown by a dotted line. The figure gives the distribution of electron density corresponding to the detected plasmon loss energy at the spatial resolution of a scanning electron microscope.

Effects of the Invention According to the present invention, it is possible to analyze band structures such as doping profiles of semiconductors with the spatial resolution of a scanning electron microscope. Since the method of the present invention is relatively simple, it can be applied to many devices.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining a method according to an embodiment of the present invention in which the method of the present invention is applied to a scanning electron microscope device, and FIG. 2 is a schematic diagram for explaining the method according to an embodiment shown in FIG. 1. A schematic diagram of a loss spectrum, and FIG. 3 is a distribution diagram of an electron density of a sample schematically showing the effect of the example method shown in FIG. 1...Electron energy analyzer, 2...
Sample, 3... Electron beam, 4... Secondary electron, 6... Plasmon loss signal, 6...
... Braun tube, 7... Deflection coil, 8...
...Electron gun, 9...Environment room.

Claims (1)

[Claims] A semiconductor analysis method that analyzes the fine band structure of semiconductor devices by analyzing the energy of electrons emitted from a sample using a scanning electron microscope using an electron beam and obtaining a plasmon energy loss signal image.