JPH01217250A - Analyzer - Google Patents

Abstract

PURPOSE:To achieve an element analysis digging the surface of a sample with depth-wise resolutions of below 10Angstrom without destroying the structure of the surface thereof, by employing an electron synchrotron radiation light in stead of ion beams. CONSTITUTION:An optical system 3 focuses a radiation light L emanated from an electron synchrotron radiation light device 1 down to a specified beam diameter to be introduced into a analyte 5 in an analysis chamber 4. An etching gas G is jetted to the analyte 5 through a nozzle 10 while it 5 is being irradiated with a light beam L, a light reaction is induced in the surface of the sample to etch. In the irradiation with light by the electron synchrotron radiation light device 1, there is little disturbance in the array of atoms. and hence, the surface of the analyte 5 can be digged down along the depth thereof with resolutions of 10Angstrom or less. After the digging to a fixed depth, an electron beam is directed from an electron gun 12, Auger electron produced is analyzed with an photoelectron energy analyzer 11, thereby achieving an analysis on electrons of the analyte 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an analysis device that can obtain analytical findings in the depth direction of a sample to be analyzed with high depth resolution.

[Conventional technology]

Conventionally, in this type of analyzer, an ion gun is used to dig in the depth direction. For example, in a device called SIMS, Ar ions from an ion gun are used to dig a hole in the depth direction of the sample surface, and the types of secondary ions emitted from the excavated area are analyzed to analyze the elements of the sample in the depth direction. Determine the concentration distribution of Other examples include Auger or XPS devices. In this case too, Ar from the ion gun
A hole is dug in a sample using an ion/beam, and after the hole has been dug to a certain depth, the elemental analysis of the surface is determined using Auger electron spectroscopy or photoelectron spectroscopy.

[Problem to be solved by the invention]

However, in conventional analyzers using an ion gun, the surface structure is destroyed by the impact effect of the ions on the sample surface, so the resolution in the depth direction is on the order of 100 A, making it difficult to obtain higher resolution. The problem was that there was no.

Therefore, the present invention solves the above-mentioned problems,
The purpose of this invention is to provide an analyzer whose resolution in the depth direction is nearly an order of magnitude higher than that using an ion gun.

[Failure to solve the problem]

In order to achieve the above object, the present invention injects etching gas from a nozzle toward the surface of an analysis sample placed in a vacuum container, and uses an optical system to emit synchrotron radiation from an electron synchrotron radiation device. The beam is focused to a predetermined beam diameter and irradiated onto the surface of the sample to be analyzed, and gas molecules or ions released from the irradiation part are detected by a detection device.

[Effect]

In the present invention, holes can be dug in the depth direction of the sample by utilizing the phenomenon that when synchrotron radiation is irradiated onto the surface of the sample to be analyzed in the presence of an etching reaction gas, the surface is etched. In this case, the intensity of the light.

By adjusting the pressure of the reactant gas and the wavelength of the light, the surface of the sample can be excavated with almost no damage.
In addition, since the amount of digging can be controlled on the order of several amps, the resolution in the depth direction is improved.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a configuration diagram showing one embodiment of an analysis device according to the present invention. 1 is an electron synchrotron radiation device; 2 is a mirror chamber/bar; 36″: J, the synchrotron radiation device 1 condenses synchrotron radiation consisting of ultraviolet or vacuum ultraviolet rays into a predetermined beam. This is an optical system that guides the sample to be analyzed 5 in the analysis chamber 4.Optical system 3
is equipped with a curved reflecting mirror 6 having a curvature constant H+ and two flat reflecting mirrors 7.8, and these reflecting mirrors 6.7
．． 8 has two types of materials on its surface that have greatly different optical constants for soft X-rays.For example, W-C, W-Be, and M.

-Be, Pt-C, Mo-8i, etc. thin films are alternately stacked to form a soft
The reflectance in a predetermined wavelength range is increased or attenuated. This takes into consideration the wavelength dependence of the reaction, which will be described later, and is considered effective in selecting a wavelength convenient for the reaction.

9 is a substrate holder, 10 is a nozzle that injects etching gas G toward the surface of the sample to be analyzed 50, and 11 is a light beam L.
This is a detection device that detects gas molecules or ions emitted from the surface of a sample by irradiation with, for example, a photoelectron energy analyzer.

Reference numeral 12 denotes an electron gun used during Auger measurement, which together with the photoelectron energy analyzer 11 forms an Auger electron spectrometer. 13 is a shutter that cuts off the light beam L in a pulsed manner.

SF6. as etching gas G. Using XeFlI, NFB or C12 in these gas atmospheres,
Semiconductors such as Si, Ge, GaAs and sio2
When the light beam L is irradiated onto the sample to be analyzed 5 made of an insulator such as SiN4, a photoreaction can be induced on the surface of the sample, and the insulator is etched.

When you want to remove 8i crystal growth or a natural oxide film on a silicon substrate by etching, it is recommended to cut short wavelength light of 50A or less and cause the reaction only with longer wavelength light to avoid carbon deposition. desirable.

For example, the etching rate is based on the data obtained by the inventors through experiments. ring light current 10
SF6 of Q, l torr when used under 0 mA
When the irradiation area was about 0.5d and 5ioz was irradiated, Sing was etched at an etching rate of about 10X/min. Furthermore, when a small amount of oxygen is added, only the portion irradiated with light is etched.

In conventional etching with an ion beam, the ions have mass, which disturbs the arrangement of atoms on the surface of the sample at the irradiation part, but in the case of light irradiation by the electron synchrotron radiation device 1 as described here, the arrangement of atoms is disturbed. is rarely disturbed. This means that the surface of the sample to be analyzed 5 can be excavated with a resolution of 10A or less while controlling the depth in the depth direction.

In order to eliminate in-plane non-uniformity in the etching depth due to the intensity distribution within the light irradiation surface, light may be irradiated while the sample to be analyzed 5 is slightly reciprocated back and forth, left and right, or rotated. .

After digging to a certain depth, as shown in this example, the electron gun 12 irradiates the surface of the excavated part with a shimiko beam, and the resulting Auger electron kinetic energy is analyzed with a photoelectron energy analyzer 11'. By doing so, if the elemental analysis of the sample 5 to be analyzed is performed at that depth, the distribution of the constituent elements or impurity elements of the sample 5 can be measured with a high resolution in the depth direction of 10A or less. Can be done. In this case, by adjusting the irradiation time of the radiation light using the shutter 13, the amount of digging that can be done at one time can be adjusted.

In this embodiment, the etching gas G is injected through the nozzle 10, the sample to be analyzed 5 is placed near the tip of the nozzle where the gas concentration is high, and a beam of synchrotron radiation is irradiated onto the area near the tip of the nozzle where the gas concentration is high. With this configuration, the average etching gas pressure within the analysis chamber 4 as a whole can be lowered, and the amount of reaction gas flowing toward the Ichiichi synchrotron radiation device 1 can be extremely reduced. Can be done in small quantities.

In this example, an Auger electron spectrometer (11°12) was used, but any surface analyzer such as an XPS or a fluorescent X-ray analyzer can also be used. It is possible to collect data of horizontal distribution.

Further, in the above explanation, the spectral distribution of the radiation emitted by the electron synchrotron radiation device 1 was not mentioned, but there is a spectral distribution suitable for the etching gas G. Optimizing the spectral distribution is also important, for example, to prevent carbon deposition on the sample surface. In order to perform such spectrum selection optimization,
The emitted light may be incident on the above-mentioned soft X-ray multilayer reflective mirror 6.7.8 at a predetermined angle of incidence to select a wavelength, and then the reflected light may be used. Furthermore, if radiation from a device called an undulator is used in place of the electron synchrotron radiation device 1, it is possible to select a spectrum and obtain a radiation beam with high intensity. Note that the multilayer reflective mirror may not be all of the three reflective mirrors 6, 7, and 8, but may be one or both of the flat reflective mirrors 7 and 8.

In FIG. 2, a spectroscope 20 is installed on the optical axis of the emitted light to make the emitted light monochromatic, and the other configurations are completely the same as those of the above embodiment. The spectrometer 20 has two reflecting mirrors 21
．． 22 and a diffraction grating 23. When analyzing a sample, first, by moving the mirrors 21 and 22 in the spectroscope 20 from a predetermined position in the direction of the arrow, the surface of the sample is etched with non-spectral light, and a hole of a predetermined depth is dug. ,
This separated light is irradiated onto the sample surface, and the mirror 21.
22 to its original position, the synchrotron radiation was spectrally dispersed, and the energy of the photoelectrons emitted thereby was detected and analyzed by the photoelectron energy analyzer 11 (Fig. 1). The photoelectron spectra of a portion can be measured, and the radiation from the electron synchrotron radiation device 1 can be effectively used for both etching and surface analysis.

〔Effect of the invention〕

As explained above, since the analyzer according to the present invention uses electron synchrotron radiation instead of an ion beam, the sample surface can be irradiated without destroying the structure of the sample surface.
It is possible to excavate a trench with a depth resolution of OA or lower, and by elemental analysis of the surface after excavation, it is possible to measure the distribution of elements with a depth resolution of a tube.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing the structure of a spectrometer when the spectrometer is used in the present invention. 1...Electron synchrotron radiation device, 2...Fist...
Mirror chamber, 311.11@optical system, 4...
Analysis chamber, 5... Sample to be analyzed, 10...-
Nozzle, 11...Φ・Photoelectronic energy analyzer, 1
2...Lu electronic gun, 13.fist...shutter, 20...
・Spectrometer. Patent applicant Nippon Telegraph and Telephone Corporation

Claims (2)

[Claims] (1) Etching gas is injected from a nozzle toward the surface of the sample to be analyzed placed in a vacuum container, and synchrotron radiation emitted from an electron synchrotron radiation device is focused into a predetermined beam diameter by an optical system. An analysis device characterized in that the surface of the sample to be analyzed is irradiated with light, and gas molecules or ions released from the irradiation part are detected by a detection device. (2) In claim 1, the detection device is a photoelectron energy analyzer, and a spectroscope for monochromating the synchrotron radiation is installed on the optical axis of the synchrotron radiation beam, and the spectroscope serves as an excitation light source for photoelectron emission of the photoelectron energy analyzer. An analytical device characterized in that a sample surface is irradiated with monochromatic synchrotron radiation.