JPH0760663B2 - Analyzer using charged particle beam - Google Patents

Description

TECHNICAL FIELD The present invention relates to an analyzer using a charged particle beam of an Auger analyzer, and in particular, it is possible to analyze a sample in the depth direction while etching the sample. The present invention relates to an analyzer using a charged particle beam.

[Prior Art] An Auger analyzer is used to analyze a sample in the depth direction.

In this analysis, Auger analysis of a sample at various depths is performed by alternately repeating Auger analysis by irradiating an electron beam and etching by irradiation of an ion beam at an analysis site.

To perform this analysis, an ion beam is used for etching the sample.

[Problems to be Solved by the Invention] In the conventional Auger analyzer, when the sample is etched by the ion beam, the ion beam is irradiated only from a specific direction at the analysis point of the sample to etch the analysis point. is doing. By the way, when selecting a crystalline sample or a sample whose surface roughness is not uniform, the ion beam is applied to the analysis site from only one specific direction, so that the etching is performed only at the analysis site. Therefore, the depth analysis could not be performed accurately.

In order to solve such a problem, it is possible to perform etching by irradiating an ion beam while rotating the sample. However, in an analysis apparatus using a charged particle beam such as an Auger analysis apparatus, a sample apparatus of a type having a rotary stage on an X, Y moving stage is used from a comprehensive point of view, so that a desired analysis point is set. When selecting and rotating the rotating stage to perform etching of the sample, the analysis point is displaced from the irradiation position of the ion beam,
The analysis point cannot be etched.

Also, even if the depth analysis can be completed while performing the analysis multiple times while etching the sample while rotating the sample,
When trying to obtain the secondary electron image of the sample for the next analysis, the sample was rotated, so that the same field of view as the first field of view could not be observed. It will be confusing when selecting the location.

The present invention solves such conventional drawbacks.
The present invention, in an analyzer using a charged particle beam equipped with a sample device of a type having a rotating stage on an X, Y moving stage, by performing etching while rotating the sample, a highly accurate depth analysis can be performed. It is intended to be possible. The second aspect of the present invention provides an analysis apparatus using a charged particle beam capable of returning the position and orientation of a sample to the state before analysis immediately after the depth analysis of a desired analysis point is completed. Is intended.

[Means for Solving the Problem] Therefore, according to the first aspect of the present invention, an X, Y moving stage for X, Y movement, and a rotation arranged on the X, Y moving stage and substantially perpendicular to the surface of the stage. A rotating stage for rotating the sample about an axis, a sample mounted on the rotating stage, means for irradiating the sample with a charged particle beam for analyzing the sample, and etching the sample. Means for irradiating the sample with an ion beam, rotating stage control means for rotating the rotating stage during etching of the sample by the ion beam, and movement of the ion beam irradiation position associated with the rotation are X, It is characterized by an analyzer using a charged particle beam equipped with an X, Y moving stage control means for automatically compensating by driving the Y moving stage.

Further, the second aspect of the present invention is characterized in that, in addition to the configuration of the first aspect of the present invention, means for automatically returning the rotary stage and the X, Y moving stage to the state before the start of etching is provided. There is.

EXAMPLES Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which 1 is a sample tilt stage of an Auger analyzer, 2 is an X moving stage, 3 is a Y moving stage, and 4 is a rotating stage (hereinafter referred to as R stage). (Abbreviated) 5 is a sample. 6 is sample 5
Is an electron beam scanning deflector, 8 is a sample etching ion beam generation source, 9 is an ion beam, and 10 is an analyzer for analyzing Auger electrons generated from the sample 5. 11, 12, 13 are X, Y, R stage drive mechanisms, 14, 15, 16 are X, Y, R stage drive circuits, 17
Is an arithmetic and control unit, 18 is an input unit, and 19 is a storage unit.
20 is a blanking electrode for controlling the irradiation of the electron beam on the sample 5, 21 is a blanking signal generation circuit, 22 is a secondary electron detector, 23 is an amplifier, 24 is a CRT, 25 is a scanning signal generator. is there. The input device 18 is provided with push button switches 18x +, 18x- for instructing the movement of the X stage. The push button switches 18x + and 18x- are for moving the X stage in the positive and negative directions respectively by an amount corresponding to the period of pressing these buttons. The input device 18 is provided with push button switches 18y +, 18y- for instructing movement of the Y stage, and push button switches 18r +, 18r- for instructing rotation of the R stage. These functions also include pushbutton switches 18
It is the same as x + and 18x−. Further, the input device 18 includes a start switch 18a, a return switch 18b, and an etching time setting unit 18
c, an etching number setting unit 18d is provided.

FIG. 2 is a diagram for explaining the main functions of the arithmetic and control unit 17, in which 17d is a pulse generator for R stage automatic rotation, and 17a and 17b are optical axes C of the X and Y stages. Reference numeral 17c is a storage unit for storing the coordinates x, y to be set, and 17c is a storage unit for storing the current angle θ of the R stage. 17e, 17
f and 17g are terminals to which X, Y, and R stage drive pulses are respectively sent according to the instruction amount when the operator manually operates. Reference numeral 17h is an X, Y moving pulse generator for compensation.

In such a configuration, first, a scanning signal is generated by the scanning signal generator 25, the sample 5 is two-dimensionally scanned by the electron beam 6, and the signal from the detector 22 accompanying this scanning is detected by the CRT 24.
The secondary electron image of the sample is displayed on the CRT24.

While observing this display image, the push button switches 18x +, 18x-, 18y +, 18y-8 and 18r +, 18r- of the input device 18 are operated. As a result, signals from these input devices 18 are sent to the arithmetic and control unit 17, and the stages 2 and 3 move or the stage 4 rotates. By such an operation, the desired analysis point is positioned at the center of the screen. In addition, the image is displayed at a desired visual field rotation angle. At this time, the arithmetic and control unit 17
The current coordinates of stages 2 and 3 are stored in the storage units 17a and 17b, respectively.
Data representing x, y are stored, and the stage 4 is stored in the storage unit 17c.
Data representing the current rotation angle θ of is stored. Next, the etching time setting unit 18c is operated to set the etching time T once, and the etching number setting unit 18d is operated to set the etching number N of the analysis portion. Then, when the start switch 18a is pressed, the arithmetic and control unit 17
Causes the storage device 19 to store the coordinate values and the angle values at the start of analysis stored in the storage units 17a, 17b, 17c. Further, the arithmetic and control unit 17 controls the scanning signal generator 25 and the blanking signal generating circuit 21 to fix and irradiate the electron beam 6 to the analysis position arranged directly below the optical axis C. The signal obtained by this irradiation is introduced into the analyzer 10, and the Auger spectrum signal of the sample surface is acquired. Next, arithmetic and control unit
The reference numeral 17 sends a signal to the ion beam generation source 8 to irradiate the analysis spot with the ion beam for a set period T to etch the analysis spot. Simultaneously with the start of this etching, a drive pulse having a constant frequency is sent from the R stage automatic rotation pulse generating section 17a to the R stage drive circuit 16, and the R stage 4 is driven.
Is automatically rotated in small steps of angle Δθ. With this rotation, the stored value indicating the rotation angle of the storage unit 17c increases at a constant speed. At this time, the compensating X, Y movement pulse generator 17h compensates for the deviation of the ion beam irradiation position from the analysis position due to the rotation of the R stage. Then, a pulse corresponding to the amount shown by the following equation is supplied to the circuits 14 and 15.

Δx = r · {cos (θ + Δθ) −cosθ} Δy = r · {sin (θ + Δθ) −sinθ} where r = (x ² + y ² ) ^1/2 cos θ = x / r sin θ = y / r As a result, With the rotation of the R stage 4 by Δθ, the X and Y stages move by the distance expressed by the above equation, so that the ion beam irradiation position is the analysis position even though the rotation stage R is rotating. There is no deviation from it. In this way, when the analysis site is etched for the time T, the arithmetic and control unit 17 irradiates the ion beam 9 and the stages 2, 3, 4
After stopping the driving of (1), the electron beam 6 is again irradiated to the analysis location to acquire the Auger analysis signal. Thereafter, similarly, the etching of the sample by the ion beam irradiation while driving the stage and Auger analysis are repeated, and the predetermined analysis is completed. Then, when you press the return switch 18b,
The arithmetic and control unit 17 moves or rotates the stages 2, 3, and 4 until the stored values in the storage units 17a, 17b, and 17c match the initial values of x, y, and θ stored in the storage unit 19, respectively. Therefore, if the sample is two-dimensionally scanned by the electron beam 6 after pressing the return switch 18b, an image having the same field of view as the image initially observed on the CRT 24 can be observed. You can continue the depth analysis smoothly by selecting the next analysis point.

As described above, the sample can be automatically rotated and etching can be performed without displacement of the irradiation position of the ion beam. Therefore, the ion beam is irradiated from various directions on the analysis site to perform uniform etching. , It enables highly accurate depth analysis.

Further, by pressing the return switch when the depth analysis of a certain analysis point is completed, the position and orientation of the sample can be immediately returned to the state before the analysis.

The above-described embodiment is merely an embodiment of the present invention and can be modified and implemented.

For example, while the embodiment described above applies the present invention to an Auger electron analysis apparatus, the present invention can also be applied to an apparatus such as an ion microanalyzer for performing analysis while etching a sample using an ion beam.

Further, in the above-mentioned embodiment, by pressing the return switch to immediately return to the initial state, the coordinates or angles of the X, Y, and R stages in the initial state are stored. It is also possible to store the integrated value of the X and Y movement amounts from the above and the integrated value of the rotation amount of the R stage, and control the X, Y, R stages to return to the initial state based on this information.

Further, in the above-described embodiment, the R stage and the like are rotated stepwise, but a DC motor may be used to rotate or move more continuously. The size may be increased and the control may be performed coarser.

Furthermore, the stage may automatically return to the state before the analysis when the depth analysis of one analysis point is completed without pressing the return switch.

[Effect] According to the first aspect of the present invention, as described above, the sample is automatically rotated, and the irradiation position of the ion beam is prevented from being displaced. Therefore, uniform etching of the analysis site is possible. Which enables highly accurate depth analysis.

Further, according to the second aspect of the present invention, the position and orientation of the sample can be immediately returned to the state before the analysis after the depth analysis of the desired analysis point is completed, and as a result, the first analysis point is selected. By observing the same visual field image as that at the time, the next analysis site can be smoothly selected, and the operability can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an apparatus for carrying out the present invention, FIG. 2 is a diagram for explaining main functions of an arithmetic control unit, and FIG. 3 is ion beam irradiation accompanying rotation of an R stage. FIG. 6 is a diagram for explaining a relationship between a positional deviation and an output from a compensating X, Y moving pulse generator. 2: X movement stage, 3: Y movement stage 4: Rotation stage, 5: Sample 6: Electron beam, 10: Analyzer 11, 12, 13: Stage drive circuit 17: Arithmetic control device 17a, 17b, 17c: Storage unit 17d : R stage automatic rotation pulse generator 17h: Compensating X, Y movement pulse generator 18: Input device 18a: Start switch 18b: Return switch 18c: Etching time setting unit 18d: Etching number setting unit 19: Memory device, 22 : Secondary electron detector

Claims (2)

[Claims] 1. An X, Y moving stage for moving X, Y,
A rotary stage arranged on the X, Y moving stage for rotating the sample around a rotary axis substantially perpendicular to the plane of the stage; a sample placed on the rotary stage; and for analyzing the sample Means for irradiating the sample with a charged particle beam, means for irradiating the sample with an ion beam for etching the sample, and a rotary stage for rotating the rotary stage during sample etching with the ion beam. A charged particle beam comprising a control means and an X, Y moving stage control means for automatically compensating the movement of the ion beam irradiation position due to the rotation by driving the X, Y moving stage. The analyzer used. 2. An analyzer using a charged particle beam according to claim 1, further comprising means for automatically returning the rotary stage and the X, Y moving stage to the state before the start of etching.