WO2015016632A1

WO2015016632A1 - Apparatus and method for composition and quantitative analysis using time of flight, and faraday cup assembly used therefor

Info

Publication number: WO2015016632A1
Application number: PCT/KR2014/007043
Authority: WO
Inventors: 이중환; 유규상; 박경수; 안승엽; 김완섭; 민원자; 정광환
Original assignee: 케이맥(주)
Priority date: 2013-07-31
Filing date: 2014-07-31
Publication date: 2015-02-05

Abstract

The present invention relates to a composition and quantitative analysis technique and, more particularly, to an apparatus and a method capable of analyzing the composition and quantity included in a wafer or a specimen using a time of flight during ion scattering. Furthermore, the present invention relates to a Faraday cup assembly for ion and electron beam current measurement which can be used for the above apparatus.

Description

Composition and Quantitative Analysis Apparatus and Method Using Flight Time, Faraday Cup Assembly

The present invention relates to a composition and quantitative analysis technology, and more particularly, to an apparatus and method capable of analyzing the composition and quantification contained in a wafer or a specimen using the time of flight during ion scattering.

In addition, the present invention relates to a Faraday Cup assembly for measuring the current of the ion and electron beam, has a penetrating portion in the center of the cup and usually passes the ion and electron beam through the penetrating portion, when measuring the current Faraday cup assembly that can measure the current of ion or electron beam without mechanical device in the vacuum chamber by measuring the current by directing the beam to the inlet of the cup separated by the penetrating part and the partition wall instead of the existing mechanical drive, An electron microscope including the Faraday cup assembly, an ion implantation device, an electron beam monitoring system, an ion beam monitoring system, and a current measuring method using the Faraday cup assembly.

Medium Energy Ion Scattering Spectrometry (MEIS) is used as a composition and quantitative analysis device.

In the case of MEIS, direct energy detection methods such as electrostatic or magnetic sector analyzers are used. In MEIS using this energy detection method, it is possible to analyze the content of elemental hydrogen (H) by filtering scattering and bounce particles of helium (He), neon (Ne), nitrogen (N), argon (Ar). It is known. However, in the case of the above method, there is a limit to the use of lighter elements such as helium, boron, etc., which are heavier than hydrogen, due to a decrease in resolution and detection yield. The lower resolution is due to the use of a filter for light element bounce analysis. The higher the atomic number, the lower the resolution.

Therefore, when the energy detection method is used in MEIS, light element analysis such as helium (He), lithium (Li), beryllium (Be), boron (B), carbon (C), and nitrogen (N) other than hydrogen (H) There is a problem that cannot be used.

Prior art related to the present invention is Korean Patent Publication No. 10-2010-0035601, which discloses a method for quantifying functional groups in an organic thin film.

On the other hand, an ion beam is a mass of ion flows accelerated through an electric field after separating electrons from an electrically neutral atom, mainly a particle-induced Xray emission (PIXE), Rutherback Back Scattering (ERB), ERD- It is mainly used for TOF (Elastic Recoil Detection-Time Of Flight), processing of materials (etching or patterning in semiconductor process), doping (doping of semiconductor materials using ion implantation), and electron beam is a mass of electron flow It is mainly used for analytical devices, such as an electron microscope, semiconductor patterning (E-beam Lithography), etc.

This ion or electron beam needs to measure current for dose control, etc. The most commonly used Faraday Cup is a conventional cup type with an opening on the top and closed sides and bottom. When ions or electrons are injected into the Faraday cup, the current amount of the beam is measured by measuring the amount of current stored therein.

4 illustrates an ion beam current measuring apparatus using a conventional Faraday cup 401. The beam irradiated from the beam generator 402 is usually irradiated where a beam such as a substrate or a sample is required. In FIG. 4, an electron microscope system using an electron beam for sample observation is illustrated. In this case, when the current measurement is required, the Faraday cup 401 that is off the path of the beam is moved by using the cup driver 403 to guide the beam into the Faraday cup 401, and then the beam is measured by the current measuring means. The amount of current is measured.

However, the conventional Faraday cup has a problem in that the current Faraday cup repeats mechanical movements on and off the path of the beam and may cause failure due to frictional wear and particle generation. In addition, since both ion and electron beams are used in very high vacuum (range below mTorr) chambers, these mechanical failures require a very complex repair, and the current-measuring wiring to the Faraday cups can also be Due to fatigue, there is a problem that often disconnection occurs. The particle generation or mechanical movement may also adversely affect the vacuum of the chamber in a very high vacuum state.

Korean Unexamined Patent Publication No. 10-2005-0106712 relates to a Faraday cup used in an ion implantation apparatus, and has a feature of driving a Faraday cup using a pneumatic cylinder, a solenoid valve, and a link mechanism. In particular, it has the advantage of using the shock absorber (shock absorber) to mitigate the impact and improve the vibration or precision generated when driving the cup assembly through the servo motor and the servo control unit for precise movement.

However, the present invention does not completely exclude the mechanical movement of the Faraday cup has a problem that the possibility of failure still exists and may cause a problem that the vacuum breaks when the pneumatic device breaks or leaks.

Japanese Laid-Open Patent Publication No. 2001-216934 relates to a Faraday cup used in an ion analyzer, and has a feature of driving a Faraday cup using an external operation mechanism and a step motor. Since the Faraday cup is placed in a specific position through the stepper motor, it is easy to determine the position and has high reliability through the use of an external control mechanism. However, there is also a possibility of failure due to mechanical movement. Problems with deposition can occur.

Japanese Patent Laid-Open No. 6-243815 relates to a Faraday cup for use in an electron microscope (Scanning Electron Microscope) using an electron beam, and provides a shielding means at the inlet and bottom of the cup so that the mechanical movement of the Faraday cup is not required. It is characterized by having. When the current measurement is not necessary, open the shield at the inlet and bottom of the cup so that the electron beam is irradiated to the sample through the cup, and during the current measurement, close the shield at the bottom of the Faraday cup to block the beam and place it in the Faraday cup. It is characterized by measuring the electric current of the charge. This invention has the advantage that the possibility of mechanical failure is small by preventing the movement of the cup itself, but since the shielding means is also moved by the mechanical driving means, there is a disadvantage that a failure may occur in the shielding means drive, and should be measured There is a disadvantage that the current amount of the beam can leak through the shielding means.

An object of the present invention is to provide a composition and quantitative analysis device capable of analyzing the components contained in the wafer or the specimen using the flight time, to solve the problems of the existing energy detection method.

Another object of the present invention is to provide a method for analyzing the composition and content of light elements such as boron (B) doped in silicon (Si) using the composition and quantitative analysis device using the above flight time.

Still another object of the present invention is applicable to the composition and quantitative analysis apparatus described above, and has a penetrating portion through which a beam can pass in the center of the Faraday cup, and the penetrating portion is separated from the cup through a partition wall, A Faraday cup with an open double cylindrical structure and a beam deflector on the top of the cup, which normally passes the beam through the penetrating portion, and when the current is measured, guides the beam through the deflector to the inlet of the cup and mechanically drives it. It is to provide a Faraday cup assembly and a current measuring method using the same, which is durable and fast to measure current by preventing friction, abrasion and disconnection.

Composition and quantitative analysis apparatus according to an embodiment of the present invention for achieving the above object is an incident part is accelerated incident particles; A collision unit in which a target to be analyzed is fixed and the incident particles accelerated from the incident unit collide with the target; A scattering unit in which the incident particles scattered and collided with the target and the components bounced back from the target fly at a scattering angle and a return angle of more than 0 ° to less than 90 °; And a flight time measuring unit measuring a time when the incident particles collided with the target and the component bounced from the target fly in the scattering unit.

In this case, the incident particles may be one or more elements selected from carbon, oxygen, nitrogen, neon, helium and argon. Specifically, the incident particles are more preferably neon or argon which is not reactive as an inert element.

In addition, the target may contain an element having an atomic weight of 1 to 16.

In addition, the scattering angle of the incident portion and the scattering portion and the return angle of the component bounced back from the target may be arranged in a range of more than 0 ° to less than 90 °. More preferably, it is more preferable to arrange | position in the range exceeding 20 degrees and less than 70 degrees.

In addition, if the scattering portion is 10mm or more can be formed without a maximum length limitation, considering the device size is more preferably formed of 10mm ~ 10m length.

Composition and quantitative analysis method according to an embodiment of the present invention for achieving the above another object is a method for analyzing the composition and quantification included in the target by using the above-described composition and quantitative analysis device, colliding the target to be analyzed Fixing to the part; The incident particles are accelerated at the incidence part to impinge the incident particles accelerated from the incidence part to the target so that the incident particles impinging on the target and the components separated from the target are scattered at an angle of more than 0 ° and less than 90 °, and Allowing the aircraft to fly back; And measuring, by the flight time measuring unit, the time when the incident particles collided with the target and the component separated from the target fly in the scattering unit.

The flight time measuring unit may further include a Faraday cup assembly for measuring ion and electron beam current.

Faraday cup assembly according to an embodiment of the present invention for achieving the another object has a through portion having an inner diameter capable of passing the beam in the center of the Faraday cup, the through portion separated from the inner space of the cup through the partition wall The upper surface of the Faraday cup is characterized in that the upper surface having a double cylindrical structure having an inlet having an inlet in which the bent beam is incident, the upper part of the Faraday cup when the current is guided by the beam through the inlet into the cup And a beam deflector that guides the beam deflector.

In this case, the beam deflector may be formed of two or more electrode plates.

In addition, by applying a high frequency voltage to the beam deflector to guide the path of the beam alternately to the through and the inlet can be measured in real time the current of the beam.

The current measuring method according to an embodiment of the present invention for achieving the above another object is a method for measuring ion and electron beam current using the Faraday cup assembly, using the beam deflector to guide the path of the beam to the inlet of the cup And measuring the current of the charge trapped in the cup, characterized in that no mechanical drive is required.

At this time, by applying a high frequency voltage to the beam deflector to guide the path of the beam alternately to the through and the inlet can be measured the current of the beam in real time.

According to the composition and quantitative analysis apparatus and method using the flight time according to the present invention, in the scattering portion of the particles particles of high atomic weight to accelerate and impinge on the target, bounced by the incident particles and scattered by the target Perform the composition and quantitative analysis by measuring the flight time of.

According to the method, the time to reach the flight time measuring unit is different even when the energy of the incident particles scattered from the target and the bounced target particles are the same due to the atomic weight difference, which is a unique characteristic of each component. Even if you do not apply the filter of light element such as boron has the advantage that can be analyzed. In addition, quantitative analysis can be performed through information based on incident amount, detector area, and incident scattering angle.

In addition, since the Faraday cup assembly of the present invention simply measures the current by moving the beam, the Faraday cup assembly prevents wear and disconnection due to mechanical driving and increases durability compared to the conventional method. In addition, noise can be generated during operation, stable current measurement, and measurement with minimal movement of the beam center axis. In addition, when a pulse voltage is applied to the beam deflector, real-time current monitoring of the beam is possible.

1 schematically shows a composition and quantitative analysis apparatus according to an embodiment of the present invention.

FIG. 2 shows B doped Si measurement results when neon (Ne) ions are used as incident particles and an energy detection method is used.

FIG. 3 shows B doped Si measurement results when neon (Ne) ions are used as incident particles and flight time measurement is used.

Figure 4 schematically shows an ion implantation apparatus using a conventional Faraday cup.

5 schematically shows the structure of a Faraday cup for ion and electron beam current measurement according to the present invention.

Figure 6 shows the structure of the beam deflector and the refraction of the beam according to the present invention.

Figure 7 schematically shows a structure viewed from the top of the Faraday cup for measuring the ion and electron beam current of the present invention.

Figure 8 shows the ion and electron beam current measurement method using the Faraday cup for current measurement of the present invention.

101: target 102: incident particles

110: incident part 120: collision part

130: scattering unit 140: flight time measuring unit

150: scattering angle (back angle) B: beam

401: Faraday Cup 402: beam generator

403: cup drive 400: Faraday cup

410: penetration portion 420: partition wall

430: entrance 500: beam generation unit

600: deflector 610: electrode

Hereinafter, with reference to the accompanying drawings, a composition and quantitative analysis apparatus and method using a flight time according to an embodiment of the present invention, Faraday cup assembly to be used will be described.

1 schematically shows a component analysis apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the illustrated composition and quantitative analysis apparatus includes an incident part 110, a collision part 120, a scattering part 130, and a flight time measuring part 140.

In the incident part 110, the incident particles 102 are accelerated. Particle accelerators of about tens to hundreds of keV may be disposed in the incidence unit 110 to accelerate the incident particles 102. More preferably, particle accelerators of about 40 keV to 400 keV may be disposed, but are not limited thereto. Do not.

In the present invention, the incident particles 102 preferably use a large atomic weight such as carbon (C), oxygen (O), neon (Ne), argon (Ar), helium (He), nitrogen (N), and the like. In this case, the light element may bounce off effectively when colliding with the target 101. More preferably, it can be proposed to use neon, argon, which is not reactive as inert particles, as incident particles.

Next, the target 101 to be analyzed is fixed to the collision part 120. In the collision part 120, the incident particles 102 accelerated from the incident part 110 collide with the target 101.

Next, in the scattering unit 130, the incident particles 102 collided with the target 101 and the components bounced back from the target 101 are scattered, that is, fly.

Next, the flight time measuring unit 140 measures the time that the incident particles 102 collided with the target 101 and the components bounced back from the target 101 fly in the scattering unit 130.

In the scattering unit 130, the lighter components fly for a short time, and the heavier components fly for a longer time. For example, if the target is boron-doped silicon and the incident particle is neon, the boron that has fallen off the target by the collision of neon will fly for a short time, and the neon scattered by the collision with the target for a long time Fly This is determined by the atomic weight inherent in the material, and the longer the length of the scattering unit 130 is, the larger the flight time difference becomes.

In the case of the conventional energy detection method, there is a problem that can not be analyzed when they have the same energy, but in the present invention, by measuring the flight time, even if they have the same energy, components with different atomic weights have different flight times. Since different, more accurate composition and quantitative analysis are possible. Therefore, the composition of the specific components included in the target to be analyzed, the content, the degree of contamination, etc. can be evaluated using the difference in time of flight.

By using such a feature, in the present invention, component analysis of elements (He, Li, Be, B, C, N, O) having an atomic weight of 1 to 16, including hydrogen, is possible. It is also possible to quantitatively analyze the yield of particles coming in.

A poor part of semiconductor processing and specimen analysis research is light element analysis. For example, quantitative analysis of the composition of B is important in the semiconductor B doped Si, but it is difficult because no analysis method is found. In addition, the presence of a contaminant layer in the semiconductor is very important. H, C, O, N analysis is very important because the elements mainly mixed in the contaminant layer are light elements such as H, C, O, and N. Therefore, when using the component analysis apparatus according to the present invention, the above light element analysis is possible, and there is an advantage that can be non-destructive analysis.

In consideration of flight time measurement, the length of the scattering unit 130 may act as an important factor in scattering incident particles or analyzing components bounced from a target. In other words, the longer the scattering portion, the higher the resolution of the equipment, and the easier the analysis. The scattering unit 130 is preferably formed in 10mm ~ 10m length, but is not limited to the maximum length.

On the other hand, the scattering angle of the incident portion and the scattering portion and the bounce angle of the component bounced back from the target may be adjusted according to the type of the incident particle or the target component, may be arranged in the range of more than 0 ° to less than 90 °, More preferably, it is arranged in the range of more than 20 degrees and less than 70 degrees.

Method for analyzing the specific composition and quantification included in the target using the component analysis device according to the present invention is as follows.

First, the target to be analyzed is fixed to the collision part.

Thereafter, the incident particles are accelerated at the incidence part to impinge the incident particles accelerated from the incidence part to the target so that the incident particles impinging on the target and the components separated from the target are scattered.

Thereafter, the flying time measuring unit measures the time that the incident particles collided with the target and the component separated from the target fly in the scattering unit. The amount of the component is then analyzed as the yield of the component.

Referring to FIG. 2, it can be seen that the boron (B) peak is included in the silicon (Si) peak. In this case, the boron peak is not separated and precise boron content analysis is impossible.

Referring to FIG. 3, it can be seen that the boron peak and the silicon peak are separated. This is due to the difference in flight time, and unlike in FIG. 2, accurate boron content analysis is possible.

TABLE 1

Ne incident energy: 100 keV, scattering part length: 60 cm

Scattering angle: The outer angle of the angle formed by the incident part and the scattering part

Referring to Table 1, it can be seen that the flight time difference between the recoiled boron (B) and the silicon (Si) scattered neon (Ne) is approximately 131 ns, and the boron (B) is You will see that you get to the flight time measurement faster.

From the above flight time, the following equations can be used to calculate scattering energy, energy of the component bounced from the target in the event of collision, and flying particle energy.

Equation 1 scattering energy

Equation 2 Energy of a component that bounces off a target in a collision

Flying Particle Energy

Meanwhile, the flight time measuring unit 140 may further include a Faraday cup assembly for measuring ion and electron beam current, as shown in FIGS. 4 to 8.

5 schematically illustrates the structure of a Faraday cup 400 for ion and electron beam current measurement of the present invention.

The Faraday cup 400 according to the present invention includes a through part 410 having an inner diameter capable of passing the beam B at the center thereof. The inner diameter is different depending on the equipment used, and the inner diameter of the beam B may be sufficient to prevent the Faraday cup 400 from being moved even when the beam B is moved due to the alignment of the beam B.

The through part 410 is separated from the inner space of the Faraday cup 400 by the partition wall 420. The inlet 430 of the cup is open on the upper surface of the Faraday cup 400, the side and the lower surface has a closed structure for beam capture when the beam (B) is incident. Thus, the Faraday cup 400 of the present invention has a double cylindrical structure in its overall form.

The beam B is supplied from the beam generator 500, and the beam generator uses a conventional ion or electron beam generation technique.

The beam deflector 600 is provided on the Faraday cup 400. When used according to the purpose of use of the equipment of the ion and electron beams, the beam B passes through the penetrating portion 410 and is irradiated onto the substrate or the specimen, but the deflector 600 is used when measuring the current of the beam B. The beam B is deflected to guide the beam B through the inlet 430 to the Faraday cup 400.

5 shows the structure of a beam deflector 600 that can be used in the present invention.

In general, the structure of the beam deflector 600 is composed of two or more cylindrical electrode plates. By applying a voltage to each electrode, an electric field is formed between the electrode plates to control the movement of the electron beam (or ion beam). At this time, the beam deflector used in the electron microscope presented in the embodiment of the present invention is composed of two electrodes, the potential distribution can be adjusted by adjusting the voltage of the two electrodes, thereby adjusting the refraction of the ion beam.

6 schematically illustrates a structure of the Faraday cup 400 for the ion and electron beam current measurement according to the present invention.

In addition, when a high frequency voltage is applied to the beam deflector 600, it is also possible to generate a pulse beam depending on the frequency. When the pulse beam is used, the beam B is periodically guided to the penetrating portion 410 and the inlet 420 of the Faraday cup 400, so that the beam B is monitored in real time through the Faraday cup 400. It becomes possible to use.

7 schematically illustrates a structure of the Faraday cup 400 for measuring ion and electron beam currents of the present invention.

The Faraday cup 400 has a double cylindrical structure as described in FIG. 4, a small circle forming a penetrating portion 410 when viewed from the top, a partition wall 420 surrounding it, and an opening opening from an edge of the partition wall ( 430 is provided in the form of concentric circles. A large circular concentric shape forming an outer circumferential surface of the Faraday cup 400 can be seen, and a strip-shaped inlet 430 larger than the size of the through portion 410 when viewed from the top and smaller than the outer circumferential surface of the Faraday cup 400. Through has a double cylindrical structure.

The Faraday cup assembly of the present invention can be used for electron microscope, which is a representative analysis equipment using an electron beam, and ion implantation device, which is a representative semiconductor processing equipment using ion beam. In addition to the above equipment, beam current measurement and Can be used for monitoring.

8 illustrates a method for measuring ion and electron beam current using the Faraday cup 400 for current measurement according to the present invention.

As shown in FIG. 8 (a), the beam B is normally irradiated to the sample through the penetrating portion 410 of the Faraday cup 400. When the current measurement of the beam B is necessary, a voltage is applied to the beam deflector 600 as shown in FIG. 8 (b) so that the path of the beam B passes through the inlet 430 of the Faraday cup 400 at the through part 410. ). It is preferable to apply the calculated voltage to the beam deflector 600 so that the degree of refraction of the beam B is minimized. As such, when the beam B is guided to the Faraday cup 400, the current is measured through a current measuring device (not shown). The current measuring device uses a microcurrent measuring device, and may use a current amplifier if necessary. A case of applying a high frequency voltage to the beam deflector 600 is illustrated in FIG. 5 (c).

Applying a high frequency voltage to the beam deflector 600 generates a pulse beam that is frequency dependent, so that the beam B periodically passes through the penetrating portion 410 and the inlet 420 of the Faraday cup 400 so that the Real-time monitoring is possible.

Although the above has been described with reference to the embodiments of the present invention, various changes or modifications may be made at the level of those skilled in the art. Such changes and modifications can be said to belong to the present invention without departing from the scope of the technical idea provided by the present invention. Therefore, the scope of the present invention will be determined by the claims described below.

Claims

An incident part at which incident particles are accelerated;

A collision unit in which a target to be analyzed is fixed and the incident particles accelerated from the incident unit collide with the target;

A scattering unit in which the incident particles scattered and collided with the target and the components bounced back from the target fly at a scattering angle and a return angle of more than 0 ° to less than 90 °; And

And a flight time measuring unit configured to measure a time when the incident particles collided with the target and the component bounced from the target fly in the scattering unit.
The method of claim 1,

The incident particle is a composition and quantitative analysis device, characterized in that selected from carbon, oxygen, neon, helium, nitrogen and argon.
The method of claim 2,

Composition and quantitative analysis device, characterized in that the incident particle is an inert element.
The method of claim 1,

The target composition and quantitative analysis device, characterized in that the target contains an element with an atomic weight of 1 to 16.
The method of claim 1,

The scattering angle of the incident portion and the scattering portion, and the bounce angle of the component bounced back from the target is disposed more than 20 ° to less than 70 ° characterized in that the composition and quantitative analysis device.
The method of claim 1,

The scattering unit is a composition and quantitative analysis device, characterized in that formed in 10mm ~ 10m long.
In the method for analyzing the composition and quantification contained in the target using the composition and quantitative analysis apparatus according to claim 1,

Fixing a target to be analyzed to a collision unit;

The incident particles are accelerated at the incidence part to impinge the incident particles accelerated from the incidence part to the target so that the incident particles impinging on the target and the components separated from the target are scattered at an angle greater than 0 ° and less than 90 °, Allowing the aircraft to fly back; And

And measuring the time at which the incident particles impinging on the target and the component separated from the target fly in the scattering unit in a flight time measuring unit.
The method of claim 1,

The flight time measuring unit further comprises a Faraday cup assembly for measuring ion and electron beam current.
To a Faraday cup for ion and electron beam current measurement,

The Faraday cup has a through part through which a beam can pass through the center,

The upper surface of the Faraday cup is characterized in that it has a double cylindrical structure with an open upper surface having an inlet for the bent beam is incident,

Faraday cup assembly on the top of the Faraday cup having a beam deflector for inducing a beam to be guided into the cup through the inlet during the current measurement.
The method of claim 9,

The beam deflector is Faraday cup assembly, characterized in that consisting of two or more electrode plates.
The method of claim 9,

Faraday cup assembly, characterized in that by applying a high frequency voltage to the beam deflector to guide the path of the beam alternately to the through and the inlet to measure the current of the beam in real time.
An electron microscope comprising the Faraday cup assembly of claim 9.
An ion implantation device comprising the Faraday cup assembly of claim 9.
An electron beam monitoring system comprising the Faraday cup assembly of claim 9.
An ion beam monitoring system comprising the Faraday cup assembly of claim 9.
An ion and electron beam current measurement method using the Faraday cup assembly of claim 9,

Directing the path of the beam to the inlet of the cup using the beam deflector;

Measuring current of the charge trapped in the cup; ion and electron beam current measurement method comprising a.
The method of claim 16,

And applying a high frequency voltage to the beam deflector to induce the path of the beam alternately to the through and the inlet to measure the current of the beam in real time.