JP2000268757A - Board inspection apparatus, board inspection system and control method for board inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent degradation of inspectional accuracy by blocking off a noise factor caused by an ion pump. SOLUTION: This board inspection apparatus 10 has grid electrodes 62, 63, 68 having air pits which pass exhausted gas from an electronic optical system 28 to ion pumps 19, 61 into exhaust pipes 29a, 29b for the ion pumps 19, 61. The grid electrode 62 is applied with a positive voltage over the potential energy of ions generated from the ion pump by a power supply 64, and the grid electrode 63 is applied with negative voltage which exceeds the potential energy shortly after electrons generated from the ion pump by the power supply 67 passing the grid electrode 62, thereby ions and electrons are prevented from entering the electronic optical system 28. The leaching electric field generated by the grid electrodes 62, 63 grounds the grid 68 for preventing ions and electrons from entering the electronic optical system 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate inspection apparatus, a substrate inspection system, and a control method of the substrate inspection apparatus, and more particularly to a method for effectively controlling a noise factor generated by an ion pump for vacuuming an electron optical system. The present invention relates to a board inspection apparatus, a board inspection system, and a control method of a board inspection apparatus that can be shut off in a short time.

[0002]

2. Description of the Related Art In a semiconductor pattern defect inspection apparatus using an electron beam, a rectangular electron beam is formed by an electron beam irradiating means and irradiated to a sample as a primary beam, and the surface of the sample is inspected. An electron image showing the state of the surface of the sample by secondary projection of secondary electrons, reflected electrons, and backscattered electrons generated according to the change in shape / material / potential onto the electron detection unit by the projection optical unit. Is described in JP-A-7-249393. Furthermore, in addition to this method, the primary beam is deflected by a Wien filter (electron beam deflecting means) to be perpendicularly incident on the sample surface, and the secondary beam is made to travel straight through the same Wien filter. A method for guiding the light to a projection optical means has been proposed in Japanese Patent Application No. 9-300275. FIG. 7 schematically shows a board inspection system including a board inspection apparatus disclosed in Japanese Patent Application No. 9-300275.

A substrate inspection system 100 shown in FIG. 1 includes a primary optical system 1, an electron gun controller 16 for controlling the primary optical system 1, a multi-stage quadrupole lens controller 17, a secondary optical system 2, and a secondary optical system for controlling the same. System lens control units 52, 54 to 56, electron detection unit 3, electron detection control unit 57 for controlling this, Wien filter 41, Wien filter control unit 53 for controlling this, stage 43, and stage voltage control unit for controlling this 51, an image signal processing unit 75, a host computer 76, a display unit 77, and a memory 78.

The primary optical system 1 has an electron gun section 10 and a multi-stage quadrupole lens system. The electron gun section 10 includes a long axis 10
0～700Myuemu, lanthanum hexaboride having an electron emission surface of the rectangular minor axis 15 [mu] m (LaB ₆₎ linear cathodes 1
1. Wehnelt electrode with a rectangular opening
nder) 12, an anode 13 for extracting an electron beam and irradiating it as a primary beam 5, and a deflector 14 for adjusting a beam axis. The electron gun control unit 16 controls an acceleration voltage, an emission current, and the like of the primary beam 5. Further, the quadrupole lens system includes a multi-stage quadrupole lens 15 that focuses the primary beam 5 under the control of the multi-stage quadrupole lens control unit 17.

The primary beam 5 emitted from the linear cathode 11
Are converged so as to have a substantially rectangular cross-sectional shape by the multi-stage quadrupole lens 15 and its control unit 17 and are obliquely incident on the Wien filter 41. Here, since the linear cathode 11 has a rectangular electron emission surface, the cross-sectional shape of the electron beam becomes substantially rectangular, so that the irradiation area on the sample is enlarged and the inspection efficiency can be improved. Note that, in addition to the rectangular shape, the inspection efficiency can be increased by using, for example, an electron beam having a long and thin cross section having an aspect ratio exceeding 1, such as a linear shape or a long ellipse. However, an electron beam having various cross-sectional shapes is not limited to an elongated shape.

The primary beam 5 is deflected by the Wien filter 41 in a direction perpendicular to the surface of the sample 42 and exits the Wien filter 41. Then, the primary beam 5
Is reduced by the cathode lens 21, which is a rotationally symmetric electrostatic lens, and has a major axis of several hundred μm and a minor axis of 25 μm on the sample 42.
Irradiated as a substantially rectangular beam of about m.

The stage 43 has a mechanism capable of freely moving horizontally with respect to each beam axis of the primary beam 5 incident on the sample 42 and the secondary beam 6 emerging from the sample 42, and is thereby set on the upper surface thereof. The entire surface of the sample 42 can be scanned by moving the sample 42. Also, stage 43
The stage voltage controller 51 allows a negative voltage to be applied to the sample 42. Thereby, the secondary electrons and the like emitted from the substrate 42 are accelerated and made incident on the secondary optical system 2 as the secondary beam 6, so that the aberration of the secondary beam 6 can be reduced. In addition, the incident damage to the sample 42 by the primary beam 5 can be reduced.

FIG. 9 shows a basic configuration of the Wien filter 41. As shown in FIG.
Are two electrodes 41a, 41b and two magnetic poles 41c, 41d of a rectangular parallelepiped, which are arranged to face each other and controlled by the Wien filter control unit 53 (see FIG. 7).
And Assuming that the Z axis is the optical axis of the projection system in the XYZ three-dimensional space shown in the figure, the Wien filter 41 has a structure in which the electric field E and the magnetic field B are orthogonal to each other in an XY plane perpendicular to the Z axis. For the incident charged particles, only the charged particles satisfying the Wien condition qE = vB (q is the particle charge, and v is the speed of the linearly charged particles) act to travel straight.

FIGS. 10 (a) and 10 (b) are explanatory diagrams of the trajectory of the electron beam passing through the Wien filter 41, and both are sectional views of FIG. 9 cut along the XZ plane (Y = 0). As shown in FIG. 10 (a), in the substrate inspection system 100, for the primary beam 5 incident on the Wien filter 41, the force F _E by the force F _B and the electric field by the magnetic field acts in the same direction, The primary beam 5 is deflected so as to be perpendicularly incident on the surface of the sample 42. The other hand, as shown in FIG. (B), two for the primary beam 6 acts on the force F _E is backward by the force F _B and the electric field generated by the magnetic field, yet satisfied Wien condition F _B = F _E Therefore, the secondary beam 6 goes straight without being deflected and enters the secondary optical system 2.

Returning to FIG. 7, the secondary optical system 2 includes a cathode lens 21, a second lens 22, and a rotationally symmetric electrostatic lens.
A third lens 23, a fourth lens 24, and a field stop 26 provided between the second lens 22 and the third lens 23 are provided. The cathode lens 21, the second lens 22, the third lens 23, and the fourth lens 24 are controlled by secondary optical system lens controllers 52, 54, 55, and 56, respectively. The secondary optics 2 also passes through a focal point F ₁ between the Wien filter 41 and the cathode lens 21, and an aperture stop 25 disposed in a focal plane 48 which is a plane perpendicular to the beam axis.
It has. The reason why the aperture stop 25 is arranged at the position of the focal plane 48 is that if the secondary beam 6 is to be imaged only by the cathode lens 21, the lens action becomes strong and aberrations are likely to occur. As shown in the diagram of the beam trajectory, both telecentric systems, that is, an optical system in which both the entrance pupil and the exit pupil exist at infinity, are formed together with the second lens 22 to perform one image formation. And
Further, an aperture angle stop 25 is provided on a focal plane 48 of the imaging optical system.
, The secondary beam 6 (beam orbit 8)
This is because it is possible to suppress the aberration of.

The electron detecting section 3 is provided with an MCP (Micro Channel).
Plate) detector 31, fluorescent plate 32, light guide 3
3 and an image sensor 34 having a CCD (Charge Coupled Device) and the like. MCP via secondary optical system 2
The secondary beam 6 incident on the detector 31 is transmitted to the MCP detector 3
1 and irradiates the fluorescent screen 32 with the fluorescent image.
Is detected as an image signal.

The image signal is supplied to an image processing unit 75, where it is subjected to various kinds of signal processing, and is supplied as image data to a host computer 76. Host computer 7
Reference numeral 6 displays the image data on the display unit 77 and saves the image data using the memory 78.

In the board inspection system 100,
The gas inside the electron optical system 28 having the primary optical system 1, the secondary optical system 2 and the sample chamber 44 is supplied to the ion pumps 19 and 61,
It is evacuated by a vacuum pump such as a turbo molecular pump 45 and a dry pump 46, and the inspection is performed in a vacuum state.

For example, it is difficult to maintain a high vacuum because the sample chamber 44 has a large internal capacity and the sample 42 needs to be frequently replaced. Therefore, the gas is exhausted to a pressure of the order of 1 × 10 ⁻⁶ Torr using the turbo molecular pump 45. Further, in order to prevent the inside of the electron optical system 28 from being contaminated by hydrocarbons or the like, a dry pump 4 is provided downstream of the turbo molecular pump 45.
6 is further connected, and the back pressure of the turbo molecular pump 45 is further exhausted. The electron gun section 10 is separated from the sample chamber 44 and the secondary optical system 2 by the differential exhaust diaphragm 18 in order to stably operate the electron gun.
1 × 10 ⁻⁷ Torr by ion pump 19 fitted to
It is kept in the following high vacuum. Further, the electron detection unit 3
Similarly, in order to prevent an increase in noise due to ions generated in the MCP detector 31, shorten the life of the MCP detector 31, and prevent damage to the MCP detector 31 due to discharge, the sample chamber 44
Is separated from the side by a differential exhaust throttle 27 and 1 × 1 by an ion pump 61 fitted to an exhaust pipe 29a.
It is kept in a high vacuum of 0 ^-7 Torr or less.

The vacuum exhaust pumps fitted to the exhaust pipes 29a and 29b of the electron detector 3 and the electron gun section 10 include:
Evacuation by a turbo-molecular pump is also possible, but electromagnetic noise and the like generated from the mechanical vibration and control signals of the turbo-molecular pump adversely affect the optical system, so that gas molecules are excited or ionized by a static magnetic field. Therefore, it is common to use an ion pump that exhausts gas with high efficiency.

[0016]

The ion pump, however, uses a chemical adsorption generated on the surface of a getter material, for example, a titanium cathode having a negative potential, by impinging ions on the cathode and sputtering the ions, and a Penning discharge. In order to ionize and trap gas molecules, the conventional substrate inspection system 100 shown in FIG.
A part of the electrons generated in step (1) enter the electron detection unit 3 and the electron gun unit 10 and have various effects on the inspection. In particular, in the electron detection unit 3, the electrons incident on the MCP detector 31 and the secondary electrons generated by the collision of the electrons with the inner walls of the exhaust pipes 29a and 29b cause an increase in noise of the MCP detector 31. There is a problem that the sensitivity of the detection of the next beam is reduced.

In the ion pump, ions are generated together with electrons due to ionizing collision of gas molecules, and the ions also enter the electron optical system. In the substrate inspection system 100 shown in FIG. 7, there is a problem that if ions emitted from the ion pumps 19 and 61 enter the electron detection unit 3 and the electron gun unit 10 respectively, they cause noise at any point. There was also.

Furthermore, it has been speculated that photons emitted from the ion pump also contribute to noise generation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to cut off the above-mentioned noise generation factor entering from an ion pump and to prevent a decrease in inspection accuracy and a substrate. An object of the present invention is to provide an inspection system and a control method of a substrate inspection apparatus.

[0020]

The present invention solves the above problems by the following means.

That is, according to the present invention, an electron beam irradiating means for irradiating a substrate as a sample with an electron beam, and guiding secondary electrons and reflected electrons emitted from the substrate upon irradiation of the electron beam. Optical system having an image projecting means for enlarging and projecting as a secondary electron beam to form an image, and an electron beam detecting means for detecting the secondary electron beam imaged by the image projecting means and outputting it as an image signal Means, and display means for receiving the image signal supplied from the electron beam detection means and displaying an electron beam image,
Provided is a substrate inspection apparatus comprising: an ion pump that exhausts gas in the electron optical system to evacuate the inside of the electron optical system to a vacuum state; and a noise factor blocking unit that blocks noise factors caused by the ion pump. Is done.

The noise factor is a charged particle, and the noise factor blocking means is provided in an exhaust passage through which gas in the electron optical system exhausted by the ion pump passes, and the noise factor blocking means passes through the gas. A blocking electrode having pores and blocking the entry of the charged particles, and a voltage having the same polarity as the polarity of the charged particles is connected to the blocking electrode so that a potential energy exceeding the energy of the charged particles is generated. And a cut-off voltage applying means for applying a cut-off voltage to the cut-off electrode, whereby the charged particles are cut off without significantly lowering the exhaust performance of the ion pump, and the inside of the electron optical system, particularly to the MCP detector, is cut off. The incidence can be prevented.

The charged particles have a first polarity and a first polarity.
And a second charged particle having a second polarity opposite to the first polarity, wherein the cut-off electrode is formed of the first charged particle generated by the ion pump. A first electrode configured to block entry, and a second electrode configured to block the second charged particles generated by the ion pump and entering through a vent of the first electrode. And the cut-off voltage applying means applies the voltage of the first polarity to the first electrode so as to generate potential energy that is connected to the first electrode and exceeds potential energy of the first charged particles. First voltage applying means and the second voltage generating means connected to the second electrode such that the second charged particles generate potential energy that exceeds the energy immediately after passing through the air hole of the first electrode. Polarity voltage above It is desirable to have a second voltage applying means for applying to the second electrode.

The substrate inspection apparatus has a ventilation hole through which the gas passes, and connects the third electrode, which is grounded and blocks the intrusion of the electric field generated from the blocking electrode into the electron optical system, to the blocking electrode. It is more preferable to further provide in the exhaust path on the side of the electron optical system.

Thus, it is possible to prevent the electric field formed by the cut-off electrode from reaching the electron optical system, particularly the secondary optical system, without significantly lowering the pumping performance of the ion pump. It is possible to prevent a decrease in detection accuracy.

The noise factor includes photons emitted from the ion pump, and the noise factor blocking means further includes an anti-reflection film formed on an inner wall surface of the electron optical system and the exhaust path. good.

According to the present invention, the above-described board inspection apparatus, central processing unit, signal processing means for processing the image signal and outputting image data, and storage means for storing the image data are provided. A board inspection system is provided.

Further, according to the present invention, an electron beam irradiating means for irradiating a substrate as a sample with an electron beam, and guiding secondary electrons and reflected electrons emitted from the substrate upon receiving the irradiation of the electron beam. Optical system having an image projecting means for enlarging and projecting as a secondary electron beam to form an image, and an electron beam detecting means for detecting the secondary electron beam imaged by the image projecting means and outputting it as an image signal Means, and display means for receiving the image signal supplied from the electron beam detection means and displaying an electron beam image,
An ion pump for exhausting the gas in the electron optical system; and an ion pump provided in an exhaust passage through which the gas in the electron optical system exhausted by the ion pump passes. A blocking electrode for blocking the entry of charged particles generated by the pump, the control method of the substrate inspection apparatus, wherein the blocking electrode so that potential energy is generated exceeding the energy of the charged particles A substrate inspection that applies a voltage of the same polarity as the charged particles to the charged particles to block the entry of the charged particles, and exhausts the gas from the vent hole to the ion pump to make the inside of the electron optical system in a vacuum state. An apparatus control method is provided.

The charged particles have a first polarity having a first polarity.
And a second charged particle having a polarity opposite to the first polarity, wherein the blocking electrode is configured to block the entry of the first charged particle generated by the ion pump. One electrode and the ion pump,
A second electrode that blocks the second charged particles that enter through the air hole of the first electrode, and a potential energy that exceeds the energy of the first charged particles is generated. The voltage of the first polarity is connected to the first
And the second polarity voltage is applied to the second electrode so that a potential energy exceeding an energy that the second charged particle has immediately after passing through the air hole of the first electrode is generated. Preferably, it is applied to the electrodes.

Further, the substrate inspection apparatus further includes a third electrode having a ventilation hole through which the gas passes, in the exhaust path on the electron optical system side of the cut-off electrode. It is further preferable that the ground electrode is grounded to prevent an electric field generated from the blocking electrode from entering the electron optical system.

The charged particles include electron or ionic particles.

Further, the substrate inspection apparatus includes an anti-reflection film covering the electron optical system and an inner wall surface of the exhaust passage, and prevents reflection of photons emitted from the ion pump in the optical system. Even better.

Further, according to the present invention, an electron beam irradiating means for irradiating an electron beam to a substrate, which is a sample, and guides secondary electrons and reflected electrons emitted from the substrate upon irradiation of the electron beam. An electron optical system having an image projecting means for enlarging and projecting as a secondary beam to form an image, and an electron beam detecting means for detecting the secondary beam formed by the image projecting means and outputting it as an image signal. Display means for displaying the electron beam image in response to the image signal supplied from the electron beam detection means, an ion pump for exhausting gas in the electron optical system, and inner walls of the electron optical system and the exhaust passage A method for controlling a substrate inspection apparatus, comprising: an antireflection film formed on a surface of the substrate inspection apparatus, wherein a base for preventing reflection of photons emitted from the ion pump in the electron optical system. The method of the inspection apparatus is provided.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same parts as those in FIGS. 7 to 10 are denoted by the same reference numerals, and description thereof will be omitted.

First, a first embodiment of the board inspection system according to the present invention will be described with reference to FIGS.

FIG. 1 shows a board inspection system 1 according to this embodiment.
FIG. 2 is a block diagram showing a schematic configuration of a block 0. As shown in FIG. 1, the board inspection system 10 includes the ion pumps 19 and 6.
The exhaust pipes 29a and 29 of the electron optical system 28 into which 1 is fitted.
9b, a noise factor blocking means 60 having three grid electrodes 62, 63, 68 as first to third electrodes and power supplies 64, 67 as voltage applying means connected to the grid electrodes 62, 63, respectively. There is a feature in the point of having.
The other points are substantially the same as those of the board inspection system 100 shown in FIG. Hereinafter, as a representative, the noise factor cutoff means provided in the exhaust pipe 29a for exhausting the gas in the electron detection unit 3 will be described.

FIG. 2 is a partially enlarged view showing a more specific configuration of the noise factor cutoff means 60. As shown in the figure, the noise factor blocking means 60 included in the board inspection system 10 of the present embodiment includes grid electrodes 62, 63, and 68 disposed in the exhaust pipe 29a. Each grid electrode is formed to have a planar shape corresponding to the cross-sectional shape of the exhaust pipe 29 a, and its peripheral edge is perpendicular to the direction in which the gas in the electron optical system 28 is exhausted to the ion pump 61. The portion is fixed to the inner wall of the exhaust pipe 29a. Each grid electrode is provided with a large number of ventilation holes so that the gas in the electron optical system 28 is exhausted without significantly lowering the exhaust efficiency of the ion pump 61.

The grid electrode 62 is connected to a power supply 64 for applying a positive voltage, and is grounded via the power supply 64.
The grid electrode 63 is connected to a power supply 67 for applying a negative voltage.
, And grounded via the power supply 67. on the other hand,
The grid electrode 68 is grounded without passing through a power supply.

The operation of the noise factor blocking means having the above configuration will be described as an embodiment of the control method of the board inspection apparatus according to the present invention.

That is, the grid electrode 62 is
Is applied with a positive voltage. Assuming that the positive voltage is Vt1 (V) and the energy of the ions 65 generated by the ion pump 61 is Vp1 (eV),
A voltage is applied to the grid electrode 62 so that Vt1> Vp1. As a result, the ions 65 leaking from the ion pump 61 cannot pass through the grid electrode 62,
It is confined between the ion pump 61 and the grid electrode 62.

Further, the grid electrode 63 is
A negative voltage is applied to. The voltage value to be applied is Vt2
(V) and let Vp2 (eV) be the energy that the electrons 69 generated by the ion pump 61 have immediately after passing through the grid electrode 62, as in the case of the power supply 64 described above, | Vt2 |> | Vp2 | Thus, a negative voltage is applied to the grid electrode 63. As a result, the electrons 69 emitted from the ion pump 61 cannot pass through the grid electrode 63, and the ion pump 61 and the grid electrode 63
Trapped between Further, secondary electrons generated by collision of the electrons 69 with the grid electrode 62 and the inner wall of the exhaust pipe 29 a are also confined between the ion pump 61 and the grid electrode 63.

On the other hand, the gas particles 6 in the electron optical system 28
6 is electrically neutral, so that the grid electrodes 68 and 6 are electrically neutral.
The ions are captured by the ion pump 61 through the vent holes 3 and 62. In this way, the ions 65 and the electrons 69 are prevented from entering the electron optical system 28 without significantly lowering the exhaust performance of the ion pump, and the MCP detector 31
Can be prevented. As a result, an increase in noise of the MCP detector 31 can be prevented.

Further, by grounding the grid electrode 68, a so-called leaching electric field caused by the electric field formed by the grid electrodes 62 and 63 reaching the secondary optical system 2 can be cut off. Thus, the MCP detector 3 can be used without significantly lowering the exhaust performance of the ion pump.
1 can prevent the detection accuracy of the secondary beam 6 from deteriorating.

As described above, according to the substrate inspection system 10 of the present embodiment, the ions and electrons generated from the ion pump, and the ions and electrons generated by the collision with the inner wall of the exhaust pipe and the grid electrode. Secondary electrons can be prevented from entering the electron optical system 28 with a simple configuration.

Next, a second embodiment of the board inspection system according to the present invention will be described with reference to FIGS.

FIG. 3 shows a board inspection system 3 according to this embodiment.
FIG. 2 is a block diagram showing a schematic configuration of a block 0. As is clear from the comparison with FIG. 1, the noise factor cutoff means 70 of the board inspection system 30 shown in FIG.
It is characterized in that it includes an antireflection film 72 covering the inner wall surface of the electron optical system 28 near 9a. Other points are shown in FIG.
Is the same as the substrate inspection system 10 shown in FIG.

The antireflection film 72 has an extremely low reflectance for photons having a short wavelength of about 1500 angstroms or less, and as shown in FIG.
To prevent reflection of photons P such as ultraviolet rays and soft X-rays radiated from.

In this embodiment, the anti-reflection film 72 is made of S
A metal-inorganic film such as iO ₂ or Si ₃ N ₄ is formed by CVD (Chemi
cal Vapor Deposition) method, the wavelength λ of photon P
Is coated so as to have a film thickness of [lambda] / 4 with respect to the incident light, and the incident photons P interfere with each other to prevent reflection of the photons P. The antireflection film is not limited to a single-layer structure, but can be made to have a multilayer film with a thickness selected so as to be an integral multiple of, for example, λ / 4. As the antireflection film, an organic antireflection film for semiconductor lithography may be used. This is to prevent reflection by light absorption, and has an advantage that the film thickness can be easily controlled in the forming process.

As described above, according to the substrate inspection system 30 of the present embodiment, the entry of ions and electrons generated by the ion pump 61 can be cut off, and Can be prevented from being reflected.

Next, a third embodiment of the board inspection system according to the present invention will be described with reference to FIGS.

FIG. 5 is a block diagram showing a schematic configuration of the board inspection system 40 according to the present embodiment.
Is the noise factor cutoff means 9 provided in the board inspection system 40
FIG. 4 is a partially enlarged view showing a more specific configuration of 0.

As is clear from comparison with FIGS. 1 and 2, the board inspection system 40 of this embodiment has a grid electrode 63 as a first electrode, one end connected to the grid electrode 63, and the other end grounded. A power supply 67 serving as a voltage applying means;
The noise factor blocking means 90 is constituted by the grid electrode 68 which is the third electrode that is grounded. The configuration excluding this noise factor cutoff means 90 is the same as the board inspection system 10 shown in FIG.
Is the same as

The noise factor cutoff means 90 of this embodiment is
Explaining, as a representative, what is provided in the exhaust pipe 29a, it operates in the same manner as in the above-described first embodiment, and the electron generated by the ion pump 61 without significantly lowering the exhaust performance of the ion pump 61. 69 is blocked from entering the electron optical system 28. Unlike the first and second embodiments described above, in the present embodiment, the ion pump 61
Although it is not possible to cut off the ions incident from the MCP or prevent the reflection of the photons, the detection of the electron beam image by the MCP detector 31 makes the entry of the electrons 69 considered to be the largest noise factor such a simple approach. It can be cut off with a simple configuration.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented with various modifications without departing from the gist thereof.
In the above-described first and second embodiments, the grid electrode 62 and the power supply 64 block the entry of the ion particles first, and then the grid electrode 63 and the power supply 67 block the entry of the electrons. The order of disposing the electrodes and the power supply may be reversed so that the entry of electrons is interrupted first, and then the entry of ion particles is interrupted. In the above-described third embodiment, the mode in which only the electrons are blocked is shown. However, it is needless to say that the mode in which only the ions are blocked or the mode in which only the reflection of photons is prevented may be employed. . In addition, the material and shape of each part can be appropriately changed according to required specifications.

[0055]

As described above in detail, the present invention has the following effects.

That is, according to the substrate inspection apparatus of the present invention, since the noise factor blocking means for blocking the noise factor generated due to the ion pump is provided, the electron beam detecting means and the electron beam irradiating means are provided. The gas in the region sensitive to noise can be evacuated by a small-sized ion pump with small mechanical vibration to create a vacuum state, and this vacuum state can be maintained stably. As a result, it is possible to prevent a decrease in detection accuracy of the board inspection apparatus, and to realize a reduction in size, weight, and cost of the entire apparatus.

The noise is caused by charged particles, and is provided in an exhaust path to the ion pump and has a ventilation hole through which the gas passes, and a voltage applying means for generating a predetermined potential energy in the shielding electrode. When the noise factor blocking means is configured by using the above, it is possible to block the charged particles from entering the electron optical system without significantly lowering the exhaust performance of the ion pump.

In the case where a third electrode which is provided in the exhaust path on the electron optical system side of the cut-off electrode and is grounded is further provided, the electric field formed by the cut-off electrode causes the electric field generated by the electron optical system. Among them, especially to the secondary optical system. Thus, it is possible to more reliably prevent the detection accuracy of the secondary beam from lowering.

When the noise factor blocking means includes an antireflection film for preventing reflection of photons emitted from the ion pump and incident, the detection sensitivity of the substrate inspection apparatus can be further stabilized.

Further, according to the substrate inspection system of the present invention, since the substrate inspection apparatus having the above effects is provided, the substrate inspection can be performed with a stable detection sensitivity without greatly lowering the exhaust performance of the ion pump. can do.

According to the control method of the substrate inspection apparatus of the present invention, a voltage having the same polarity as that of the charged particles is applied to the cut-off electrode so as to have a potential energy exceeding the energy of the charged particles. The entrance of the charged particles can be blocked. As a result, it is possible to prevent a decrease in the detection accuracy of the board inspection device.

Further, a third electrode is further provided in the exhaust passage closer to the electron optical system than the cut-off electrode.
When the electrode is grounded, the electric field generated from the blocking electrode blocks the intrusion into the electron optical system.
The detection accuracy of the substrate inspection device can be further stabilized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of a board inspection system according to the present invention.

FIG. 2 is a partially enlarged view showing a more specific configuration of a noise factor blocking unit provided in the board inspection system shown in FIG.

FIG. 3 is a block diagram showing a schematic configuration of a second embodiment of the board inspection system according to the present invention.

FIG. 4 is a partially enlarged view showing a more specific configuration of a noise factor blocking unit provided in the board inspection system shown in FIG.

FIG. 5 is a block diagram showing a schematic configuration of a third embodiment of the board inspection system according to the present invention.

FIG. 6 is a partially enlarged view showing a more specific configuration of a noise factor blocking unit provided in the board inspection system shown in FIG.

FIG. 7 is a block diagram illustrating a schematic configuration of an example of a conventional board inspection system.

FIG. 8 is an explanatory diagram showing a trajectory of an electron beam in the substrate inspection system shown in FIG.

FIG. 9 is an explanatory diagram illustrating a basic configuration of a Wien filter included in the substrate inspection system illustrated in FIG. 7;

FIG. 10 is an explanatory diagram of an orbit of an electron beam passing through a Wien filter shown in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary optical system 2 Secondary optical system 3 Electron detection part 5 Primary beam 6 Secondary beam 7 Primary beam orbit 8 Secondary beam orbit 9 Aperture position surface 10, 30, 40 Substrate inspection system 11 Linear cathode 12 Wehnelt electrode 13 Anode Reference Signs List 14 deflector 15 multi-stage quadrupole lens 16 electron gun control unit 17 multi-stage quadrupole lens control unit 18 differential exhaust diaphragm 19, 61 ion pump 20 electron gun unit 21 cathode lens 22 second lens 23 third lens 24 first Four lenses 25 Aperture stop 26 Field stop 27 Differential exhaust stop 28 Electro-optical system 29a, 29b Exhaust pipe 31 MCP detector 32 Fluorescent plate 33 Light guide 34 Image pickup device 41 Wien filter 41a, 41b Electrode 41c, 41d Magnetic pole 42 Sample 43 Stage 44 Sample chamber 45 Turbo molecular pump 46 Dora I pump 48 Focal plane 51 Stage voltage control unit 52 Cathode lens control unit 53 Wien filter control unit 54 Second lens control unit 55 Third lens control unit 56 Fourth lens control unit 57 MCP detection system control unit 60, 70, 90 Noise factor Blocking means 62, 63, 68 Grid electrode 64, 67 Power supply 65 Ions 66 Gas particles 69 Electrons 72 Anti-reflection film 75 Image signal processing unit 76 Host computer 77 Display unit 78 Memory P Photon

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Takashi Nagai, Inventor 8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Inside the Toshiba Yokohama Office (72) Inventor Motosuke Miyoshi Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa No. 8 F-term in Toshiba Yokohama Office of Stock Company (Reference) 2F067 AA54 BB01 BB04 CC17 EE03 HH06 JJ05 KK04 KK08 LL16 MM04 QQ02 RR30 RR35 2G001 AA03 BA07 BA14 CA03 FA16 GA09 HA13 JA02 JA11 JA03 JA05 BA03 DB03 MA03 DJ23 5C033 KK04

Claims (15)

[Claims] An electron beam irradiating means for irradiating an electron beam to a substrate which is a sample;
An electron optical system having an image projection unit that guides secondary electrons and reflected electrons emitted from the substrate to expand and project as a secondary electron beam to form an image, and the secondary image formed by the image projection unit. An electron beam detection unit that detects an electron beam and outputs the image signal as an image signal; a display unit that receives the image signal supplied from the electron beam detection unit and displays an electron beam image; A substrate inspection apparatus comprising: an ion pump that evacuates the inside of the electron optical system to a vacuum state; and a noise factor blocking unit that blocks a noise factor caused by the ion pump. 2. The noise factor is a charged particle, and the noise factor blocking means is provided in an exhaust passage through which gas in the electron optical system exhausted by the ion pump passes, and the noise factor blocking means passes through the gas. A blocking electrode having a ventilation hole for blocking the entrance of the charged particles, and a voltage connected to the blocking electrode and having the same polarity as the polarity of the charged particles such that potential energy exceeding the energy of the charged particles is generated. And a cut-off voltage applying means for applying a voltage to the cut-off electrode.
A substrate inspection apparatus according to item 1. 3. The charged particle according to claim 1, wherein the charged particle has a first polarity.
And a second charged particle having a second polarity opposite to the first polarity, wherein the blocking electrode comprises a first charged particle generated by the ion pump. A first electrode for blocking the entry, and a second electrode for blocking the second charged particles generated by the ion pump and entering through the vent of the first electrode.
And the cut-off voltage applying means is connected to the first electrode and generates the potential of the first polarity so that potential energy exceeding energy of the first charged particle is generated. A first voltage applying means for applying a voltage to one electrode; and a second charged particle connected to the second electrode, the second charged particle being applied to the first electrode.
The second energy so as to generate a potential energy exceeding the energy immediately after passing through the air hole of the first electrode.
3. The substrate inspection apparatus according to claim 2, further comprising: a second voltage applying unit configured to apply a voltage having a polarity of the second polarity to the second electrode. 4. The substrate inspection apparatus according to claim 2, wherein the charged particles include electrons. 5. The substrate inspection apparatus according to claim 2, wherein said charged particles include ion particles. 6. A third electrode having a ventilation hole through which the gas passes, and a third electrode, which is grounded to block an intrusion of an electric field generated from the cut-off electrode into the electron optical system, is more than the cut-off electrode. The substrate inspection apparatus according to any one of claims 2 to 5, further comprising an exhaust path on the optical system side. 7. The noise factor includes a photon emitted from the ion pump, and the noise factor blocking unit includes an anti-reflection film formed on an inner wall surface of the electron optical system and the exhaust path. The substrate inspection apparatus according to any one of claims 1 to 6, wherein: 8. A substrate inspection apparatus according to claim 1, a central processing unit, a signal processing means for processing the image signal and outputting image data, and a storage for storing the image data. And a substrate inspection system. 9. An electron beam irradiating means for irradiating a substrate as a sample with an electron beam;
An electron optical system having an image projection means for guiding secondary electrons and reflected electrons emitted from the substrate to form a secondary electron beam by enlarging and projecting the electron beam, and the secondary image formed by the image projection means. An electron beam detection unit that detects an electron beam and outputs the image signal as an image signal; a display unit that receives the image signal supplied from the electron beam detection unit and displays an electron beam image; An ion pump for evacuating, and an exhaust passage provided in an exhaust path through which gas in the electron optical system exhausted by the ion pump passes, and having a ventilation hole for allowing the gas to pass therethrough, and charging generated by the ion pump. A blocking electrode for blocking the entry of particles, comprising: a potential electrode exceeding an energy of the charged particles; In order to generate energy, a voltage having the same polarity as that of the charged particles is applied to the cut-off electrode so as to block the entry of the charged particles, and the gas is exhausted from the vent hole to the ion pump to thereby generate the electro-optical device. A method for controlling a substrate inspection apparatus that evacuates the inside of a system. 10. The charged particles include a first charged particle having a first polarity and a second charged particle having a polarity opposite to the first polarity.
Wherein the blocking electrode includes a first electrode configured to block entry of the first charged particles generated by the ion pump, and a first electrode generated by the ion pump. A second electrode that blocks the entry of the second charged particles that enter through the ventilation hole of the electrode, and the potential energy that exceeds the energy of the first charged particles is generated. A voltage having a first polarity is applied to the first electrode, and the second charged particles generate a potential energy exceeding an energy that is immediately after passing through the air hole of the first electrode. The method according to claim 9, wherein a voltage having two polarities is applied to the second electrode. 11. The method according to claim 9, wherein the charged particles include electrons. 12. The control method according to claim 9, wherein said charged particles include ion particles. 13. The substrate inspection apparatus further comprises a third electrode having a vent for allowing the gas to pass therethrough in the exhaust path on the electron optical system side of the cut-off electrode. The control method for a substrate inspection apparatus according to claim 9, wherein grounding is performed to block an electric field generated from the blocking electrode from entering the electron optical system. 14. The substrate inspection apparatus according to claim 1, further comprising: an anti-reflection film covering the electron optical system and an inner wall surface of the exhaust path, for preventing photons emitted from the ion pump from being reflected in the optical system. A method for controlling a substrate inspection apparatus according to any one of claims 9 to 13. 15. An electron beam irradiating means for irradiating a substrate as a sample with an electron beam, and receiving the electron beam to guide secondary electrons and reflected electrons emitted from the substrate to expand as a secondary beam. An electron optical system having a projection unit for projecting and forming an image, an electron beam detection unit for detecting the secondary beam formed by the projection unit and outputting the image as an image signal, and the electron beam detection unit Display means for displaying an electron beam image in response to the image signal supplied from the apparatus, an ion pump for exhausting gas in the electron optical system, and reflection formed on the inner wall surfaces of the electron optical system and the exhaust path. A method for controlling a substrate inspection apparatus, comprising: an anti-reflection film; and a reflection method for preventing reflection of photons emitted from the ion pump in the electron optical system. .