JPS62246241A - Charged particle beam device - Google Patents

Abstract

PURPOSE:To analyze stably without charging a sample, by emitting the second charged particle beams with the charge inverse to the first charged particle beams, to the spot of radiation of the first charged particle beams for the sample. CONSTITUTION:A net 3 consisting of a conductor is furnished to cover a sample table 1, the first charged particle beams 4 are radiated almost vertically on the sample 2, and the produced secondary ions 5 are introduced to a mass analyzer or the like through a drawing out electrode 6. In this case, a sample beam source 7 is furnished inside the net 3, connected to a power source through an insulating transfromer 8, and electron beams 9 are radiated on a specific spot of the sample 2 at any time. Furthermore, the sample beam source 7 is connected to the net 3 through a lead wire 7a, and kept at the same potential as the net 3. Therefore, the electric field within the net 3 is stablized, the positive charge over the sample 2 is neutralized by the electron beams 9, and the analysis can be carried out stably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to charged particle beam technology, and particularly to a technology that is effective when applied to the analysis of insulators and the like.

[Prior art] Charged particle beam equipment is available from Kogyo Kenkyukai Co., Ltd.
Published November 15, 1983, [Electronic Materials J 1983
It is described on pages 116 to 123 of the November issue, special issue.

By the way, the present inventor studied a technique for analyzing a sample using a charged particle beam device. The following is a technology considered by the present inventor, although it is not a publicly known technology, and its outline is as follows.

That is, by irradiating the surface of a sample with an ion beam of a predetermined substance and analyzing the secondary ions generated from the sample using a mass spectrometer or the like, the elements constituting the sample can be ascertained.

[Problems to be Solved by the Invention] However, in the above-mentioned charged particle beam device, if the sample is made of an insulator, the sample is charged by irradiation with the ion beam, making it difficult to perform stable analysis. The inventor has discovered that there is a problem in that it is not possible to do so.

In addition, in order to avoid such problems, for example, it is possible to irradiate the sample with high-energy neutral particles, but the present invention also explains that this may cause new problems such as heating of the sample surface. discovered by someone.

An object of the present invention is to provide charged particle beam technology that allows stable analysis without charging a sample.

The above and other objects and novel features of the present invention include:
It will become clear from the description herein and the accompanying drawings.

[Means for Solving the Problems] A brief overview of typical inventions disclosed in this application is as follows.

That is, together with the first charged particle beam, a second charged particle beam having an opposite charge to that of the first charged particle beam is irradiated onto the sample.

[Function] According to the above-described means, for example, in a sample made of an insulator, the charge on the sample caused by irradiation with the first charged particle beam is neutralized by irradiation with the second charged particle beam. , stable analysis can be performed without charging the sample.

[Embodiment 1] FIG. 1 is an explanatory diagram showing the main parts of a charged particle beam device which is an embodiment of the present invention.

A sample 2 made of, for example, an insulator is placed on a sample stage 1 .

The sample stage 1 is provided with a wall 3 made of a sensitive body so as to surround the sample 2 placed on the sample stage 11.

Further, above the sample stage 1, a positive ion beam 4, for example, is placed almost perpendicularly to the sample 2 from an ion source (not shown).
(first charged particle beam) is irradiated, and the secondary ions 5 generated from the surface of the sample 2 at this time are
The structure is such that the ions are led to an external mass analyzer (not shown) through the secondary ion extraction electrode 6, and the elements constituting the sample 2 are analyzed.

In this case, a sample radiation source 7 is provided inside m3 provided so as to surround the sample 2, and is connected to a power source (not shown) via an isolation transformer 8, so that it can be applied to a predetermined portion of the sample 2 at any time. Electron beam 9 (second charged particle beam)
is configured to be irradiated.

In addition, the sample radiation source 7 is connected to a conductor by a conducting wire 7a. A3, so that the wire 3 and the sample 'la source 7 are at the same potential.

The operation of this embodiment will be explained below.

First, a positive ion beam 4 is irradiated onto a predetermined part of the sample 2 from an ion source (not shown), and the sample vA source 7
From then on, the same region is irradiated with the electron beam 9.

At this time, secondary ions 5 such as substances constituting the sample 2 are emitted from the surface of the sample 2 by irradiation with the positive ion beam 4, and these secondary ions 5 are transferred to the secondary ion extraction electrode 6.
The sample 2 is then sent to a mass spectrometer (not shown), where the type of substance forming the secondary ions 5, ie, the type of substance forming the sample 2, etc. is determined.

Here, if the sample 2 is made of an insulator or the like, the sample 2 is positively charged by irradiation with the cation beam 4,
Due to the electric field formed on the sample surface, etc., the incident velocity of the secondary ions 5 to the secondary ion extraction electrode 6 fluctuates greatly, and it is inevitable that the analysis operation of the secondary ions 5 becomes unstable. However, in Example 1, the sample 2 is irradiated with the negatively charged electron beam 9 from the sample radiation source 7 at any time to neutralize the positive charge on the sample 2, so that the secondary ions 5 cannot be analyzed. , always performed stably.

As described above, in this embodiment, the following effects can be obtained.

(1) Positive ion beam 4 (first charged particle beam) irradiated to emit secondary ions 5 from sample 2
At the same time, since the structure is such that the electron beam 9 (second charged particle beam) is irradiated from the sample source 7 at any time, for example, when the sample 2 is made of an insulator, the sample 2 is irradiated with the cation beam 4. The electrification of the secondary ions 5 is neutralized by irradiation with the electron beam 9, so that stable analysis of the secondary ions 5 can be performed at all times.

(2) As a result of <11 above, even if the sample 2 is an insulator, it becomes a target of analysis, and the range of the sample 2 that can be analyzed is expanded.

(3) By making the potentials of the sample radiation source 7 and the net 3 surrounding the sample 2 equal, the electric field inside the net 3 is stabilized, and the irradiation of the electron beam 9 onto the sample 2 is stabilized. At the same time, the sample 2 is prevented from being heated.

(4) Since the sample radiation source 7 is provided inside the net 3, it is possible to prevent the surface of the sample 2 from being contaminated by the substance constituting the sample line a7.

[Embodiment 2] FIG. 2 is an explanatory diagram showing the main parts of a charged particle beam device that is another embodiment of the present invention.

The second embodiment is different from the first embodiment in that the sample radiation source 7 is grounded via a resistor 10 having a relatively large resistance value, and the amount of current applied to the sample radiation source 7 is , can be adjusted from both the primary and secondary sides of the isolation transformer 8.

In the second embodiment, the following effects can be obtained.

(1) Positive ion beam 4 (first charged particle beam) irradiated to emit secondary ions 5 from sample 2
In addition, since the structure is such that the electron beam 9 (second charged particle beam) is irradiated from the sample radiation source 7 at any time, for example, when the sample 2 is made of an insulator, the cation beam 4 irradiates the sample 2. The electrification of the secondary ions 5 is neutralized by the irradiation with the electron beam 9, so that stable analysis of the secondary ions 5 can be performed at all times.

(2) As a result of (11) above, even if the sample 2 is an insulator, it becomes a target of analysis, and the range of the sample 2 that can be analyzed is expanded.

(3) Since the sample radiation source 7 is provided inside the net 3, it is possible to prevent the surface of the sample 2 from being contaminated by the substance constituting the sample radiation source 7.

(4) The sample radiation source 7 is a resistor 1 with a relatively large resistance value.
Since the sample line a7 is grounded through 0, the communication from both the primary side and the secondary side of the sample line a7 to the sample source 7 is prevented.
can be controlled.

[Embodiment 3] FIG. 3 is an explanatory diagram showing the main parts of a charged particle beam apparatus which is still another embodiment of the present invention.

In the third embodiment, the sample radiation source 7 is located outside the net 3 surrounding the sample 2, and the sample line 'tA7
A power supply 11 for operating the sample radiation source 143 is provided between the sample radiation source 7 and the sample radiation source 7.

In the third embodiment, the following effects can be obtained.

(l), emit secondary ions 5 from sample 2 (irradiated positive ion beam 4 (first charged particle beam)
In addition, since the structure is such that the electron beam 9 (second charged particle beam) is irradiated from the sample radiation source 7 at any time, for example, when the sample 2 is made of an insulator, the ion beam 4 irradiates the sample 2. The electrification of the secondary ions 5 is neutralized by the irradiation with the electron beam 9, so that stable analysis of the secondary ions 5 can be performed at all times.

(2) As a result of (1) above, even if the sample 2 is an insulator, it becomes a target of analysis, and the range of the sample 2 that can be analyzed is expanded.

(31, the sample radiation source 7 is located outside the net 3 provided surrounding the sample 2, and the power supply 1 for operating the sample radiation source 7
1 is provided between the net 3 and the sample beam source 7, the potential between the net 3 and the sample line B7 is stabilized, and the electron beam 9 is irradiated from the sample beam source 7 to the sample 2. can be easily performed.

[Embodiment 4] FIG. 4 is an explanatory diagram showing the main parts of a charged particle beam apparatus which is Embodiment 4 of the present invention.

In the fourth embodiment, a shielding body 12 is interposed between the sample radiation source 7 provided outside the net 3 and the political platform 3, and the electron beam 9 emitted from the specimen radiation source 7 is transmitted through the shielding body 12. ′! is formed nearby! The i1 field or the magnetic field 13 is configured to bypass the shield 12 and irradiate the sample 2.

In the fourth embodiment, the following effects can be obtained.

+1+, along with the positive ion beam 4 (first charged particle beam) that is irradiated to emit secondary ions 5 from the sample ks source 7, an electron beam 9 (second charged particle beam) is irradiated from the sample ks source 7 at any time. For example, when the sample 2 is made of an insulator, charging of the sample 2 due to irradiation with the positive ion beam 4 is caused by electron beam 9.
The secondary ions 5 are neutralized by the irradiation, so that stable analysis of the secondary ions 5 can be performed at all times.

(2) As a result of the above +1+, even if the sample 2 is an insulator, it becomes a target of analysis, and the range of the sample 2 that can be analyzed is expanded.

(31,' A shielding body 12 is interposed between the sample radiation source 7 provided outside of #A3 and the net 3, and the electron beam 9 emitted from the specimen radiation source 7 is directed to the vicinity of the shielding body 12. By bypassing the shielding body 12 and irradiating the sample 2 with the electric or magnetic field 13 being formed, for example, the sample [[
Neutral particles of the substance constituting the sample 7 are prevented from reaching the sample 2 and contaminating the sample 2.

[Embodiment 5] FIG. 5 is an explanatory diagram showing the main parts of a charged particle beam apparatus which is Embodiment 5 of the present invention.

In the fifth embodiment, instead of the electron beam 9, a positive ion beam 4 is emitted from an ion beam source (not shown).
The sample 2 is configured to be irradiated with a negative ion beam 14 having an opposite charge to the sample 2 at any time.

In the fifth embodiment, the following effects can be obtained.

(1) Along with a positive ion beam 4 (first charged particle beam) that is irradiated to emit secondary ions 5 from the sample 2, a negative ion beam 14 (second charged particle beam) is emitted from an ion beam source (not shown). ) is irradiated at any time, for example, when the sample 2 is made of an insulator, the charge on the sample 2 caused by the irradiation with the cation beam 4 is neutralized by the irradiation with the anion beam 14, so that the sample 2 is always stable. Secondary ions 5 can be analyzed.

(2) As a result of (1) above, even if the sample 2 is an insulator, it becomes a target of analysis, and the range of the sample 2 that can be analyzed is expanded.

[Example 6] FIG. 6 shows a charged particle beam vt which is Example 6 of the present invention.
FIG. 2 is an explanatory diagram showing the main part of yl.

In the sixth embodiment, a plurality of detectors for detecting secondary ions 5 that have deviated from a predetermined trajectory are installed behind the mass spectrometer 15 connected to the secondary ion extractor 6 that captures the secondary ions 5. 16 and a detector 17 are provided, and this detection RW
16 and 17 are connected to a control section 18 that controls the sample radiation source 7.

Then, the 'Etli1 analysis of the secondary ions 5, which changes due to the charging of the sample, is performed to detect the change in the charging state of the sample 2, which changes depending on the excess or deficiency of the electron beam 9 irradiated onto the sample 2 from the sample radiation source 7. a change in the velocity of incidence on the vessel 15;
That is, secondary ions 5 to detectors 16 and 17
By detecting this as a change in the amount of electron beams reached and feeding back to the control unit 18, the amount of irradiation of the electron beam 9 irradiated from the sample vA source 7 to the sample 2 is determined to be the optimum amount for neutralizing the charge on the sample 2. It is something to be controlled carefully.

As described above, in the sixth embodiment, the following effects can be obtained.

(1) Positive ion beam 4 (first charged particle beam) irradiated to emit secondary ions 5 from sample 2
In addition, since the structure is such that the electron beam 9 (second charged particle beam) is irradiated from the sample radiation source 7 at any time, for example, when the sample 2 is made of an insulator, the cough sample 2 due to irradiation with the cation beam 4 is The electrification of the secondary ions 5 is neutralized by the irradiation with the electron beam 9, so that stable analysis of the secondary ions 5 can be performed at all times.

(2) As a result of (11) above, even if the sample 2 is an insulator, it becomes a target of analysis, and the range of the sample 2 that can be analyzed is expanded.

(3) Detectors 16 and 17 are provided to detect excess or deficiency of the irradiation amount of the electron beam 9 on the sample 2, and the control unit 18 uses the information obtained by the detectors 16 and 17.
Through this, the amount of irradiation of the electron beam 9 to the sample 2 is controlled to the optimum amount for neutralizing the electrical charge on the sample 2, thereby simplifying the adjustment and operation of the apparatus.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. For example, the first charged particle beam is not limited to an ion beam, but may also be an electron beam.

In the above explanation, the invention made by the present inventor was mainly applied to the field of application which is the background of the invention, which is a sample analysis technique using charged particle beam irradiation, but the invention is not limited to this, for example, It can be widely applied to techniques such as microfabrication of samples by irradiation with charged particle beams.

[Effects of the Invention] The effects obtained by typical inventions disclosed in this application are briefly described below.

That is, in a charged particle beam apparatus that analyzes a sample by irradiating the surface of the sample with a first charged particle beam, the first charged particle beam is applied to the irradiation site of the sample with the first charged particle beam. Because the structure has a sample radiation source that irradiates a second charged particle beam with an opposite charge to that of the beam, for example, in a sample made of an insulator, there is no possibility of radiation caused by the irradiation of the first charged particle beam. the charge on the sample is neutralized by irradiation with the second charged particle beam;
Stable analysis can be performed without charging the sample.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the main parts of a charged particle beam device which is an embodiment of the present invention. FIG. 2 is an explanatory diagram showing the main parts of a charged particle beam device which is another embodiment of the invention. , FIG. 3 is an explanatory diagram showing the main parts of a charged particle beam device which is still another embodiment of the present invention, and FIG. 4 shows the main parts of a charged particle beam device which is a fourth embodiment of the present invention. Explanatory diagram: FIG. 5 is an explanatory diagram showing the main parts of a charged particle beam device according to the fifth embodiment of the present invention; FIG. 6 is an explanatory diagram showing the main parts of the charged particle beam device according to the sixth embodiment of the present invention. It is an explanatory diagram. 1... Sample stand, 2... Sample, 3... Net, 4...
Positive ion beam (first charged particle beam), 5... Secondary ions, 6... Secondary ion extraction electrode, 7... Sample radiation source, 7a... Conductive wire, 8... Insulation transformer , 9・
...Electron beam (second charged particle beam), 10...
Resistor, 11...power supply, 12...m image body, 13...
・Electric field or magnetic field, 14... Negative ion beam (second charged particle beam), 15... Mass spectrometer, 16° 17
...Detector, 1'8...Control unit. Figure 1 Figure 2 Coupling power 5tl:...Hirodai Figure 3 Figure 4 Figure 5 Figure 6/,S

Claims (1)

[Scope of Claims] 1. A charged particle beam device that analyzes a sample by irradiating the surface of the sample with a first charged particle beam, the portion of the sample being irradiated with the first charged particle beam; A charged particle beam device comprising: a sample radiation source that irradiates a second charged particle beam having a charge opposite to that of the first charged particle beam. 2. The charged particle beam device according to claim 1, wherein the first and second charged particle beams are an ion beam and an electron beam, respectively. 3. The sample radiation source is connected to a power source via an isolation transformer, is provided inside a network of conductors surrounding the sample, and is at the same potential as the network. A charged particle beam device according to claim 2 characterized by: 4. Claim 3, characterized in that the sample radiation source is grounded via a resistor with a relatively high resistance value.
Charged particle beam device as described in . 5. A patent claim characterized in that the sample radiation source is provided outside a network made of conductors surrounding the sample, and a power source for the sample radiation source is provided between the network and the network. The charged particle beam device according to item 2. 6. A shield is interposed between the sample radiation source and the net,
Charged particle beam device according to claim 5, characterized in that the electron beam emitted from the sample radiation source bypasses the shielding body and reaches the sample by the action of an electric field or a magnetic field. . 7. The charged particle beam device according to claim 1, wherein the first and second charged particle beams are ion beams having opposite charges. 8. A detector is provided to detect the amount of charge of a second charged particle beam irradiated from the sample radiation source to the sample, and based on information from the detector, the amount of charge of the second charged particle beam irradiated from the sample radiation source to the sample is 2. The charged particle beam device according to claim 1, wherein the second charged particle beam is controlled.