JP2003323860A - Electron beam equipment and manufacturing method of device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic beam equipment using an electron gun wherein brightness is increased by efficiently heating the cathode. <P>SOLUTION: This electronic beam equipment is provided with an electron gun having a thermionic emission cathode 1, a Wehnelt 2 and an anode 3, and a shaft centering device 4 for adjusting the positions of the cathode 1, Wehnelt 2 and the anode 3. When an accelerating voltage in the electron gun is taken as Vo volt, a current is made to flow into the electron gun so that the brightness is 1×10<SP>6</SP>×(Vo/4.5×10<SP>3</SP>) A/cm<SP>2</SP>sr or more. When the Vo is 4.5 kV, it is desirable that the brightness of the electron gun is 1×10<SP>6</SP>A/cm<SP>2</SP>sr or more, and a crossover made by the electron gun is formed on a sample side from the anode. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of efficiently heating a thermionic emission cathode to obtain an electron beam having a much higher brightness than that currently used, and has a large beam current and each beam. Electron beam apparatus capable of generating multi-beams with small intensity variation between devices, and device manufacturing with improved yield by evaluating wafers in process using beams produced by the electron beam apparatus Regarding the method.

[0002]

2. Description of the Related Art In an electron gun used in a conventional electron beam apparatus, a field of a magnetic lens is superposed on the electron gun in order to increase the brightness of a thermionic emission cathode. Further, an electron gun having a thermionic emission cathode generally has low brightness when operated under space charge limiting conditions, and it is said that maximum brightness is obtained when operated under temperature limiting conditions. There is. Further, when heating a cathode having a relatively large circle diameter, it is difficult to directly heat such a cathode, so that side heat by electron bombardment or the like is usually used.

In the multi-beam type electron beam apparatus, the multi-beam is usually formed by the Koehler illumination system or the critical illumination system. On the other hand, in order to form a multi-beam, an electron gun having a Wehnelt aperture having a plurality of protrusions and an anode has been proposed.

The brightness obtained by the conventional LaB ₆ electron gun is 6.8 × 10 ⁶ A / cm ^{2 at} 20 kV.
It is about sr, and 8 × 10 ⁴ A / cm ² s at 4.5 kV
It is about r.

[0005]

However, in order to superimpose a magnetic field on the electron gun, the structure of the electron beam device is complicated, and the aberration can only be reduced. Can not do it. Further, the indirectly heated cathode has a problem that the efficiency is low and the structure and the control power source are complicated. Moreover, the brightness of the electron gun having the thermionic emission cathode is smaller than that of the electron gun having the TFE cathode by two digits or more.

When a multi-beam is obtained by the Koehler illumination system, if the crossover positions formed by the respective beams and the crossover positions formed by the individual beams do not match, which position of the NA aperture should be matched? There is a problem that is not decided. On the other hand, in an electron gun having a plurality of projections and a Wehnelt opening, it is necessary to make the positional accuracy of each projection and the Wehnelt opening strict.

The present invention has been proposed to solve the above-mentioned various problems, and one object of the present invention is to provide a method for efficiently heating the cathode and an electron beam using an electron gun with increased brightness. To provide a device.

Another object of the present invention is to provide an electron beam apparatus having a multi-beam system which can be adapted even if the crossover positions of the individual beams and the crossover positions of the respective beams do not match.

Another object of the present invention is to provide an electron beam apparatus which can form a multi-beam with one cathode and which does not require strict positional accuracy for the cathode and Wehnelt.

Still another object of the present invention is to provide an electron beam apparatus using an electron gun which can obtain a brightness larger than that of the conventional one by one digit even when the electron gun having a cathode made of LaB ₆ is used. Especially.

Another object of the present invention is to provide a method of manufacturing a device with good yield using these electron beam apparatuses.

[0012]

In order to achieve the above object, the invention of claim 1 is an electron beam apparatus including an electron gun having a thermionic emission cathode, a Wehnelt and an anode. The luminance is 1 × 10 ⁶ × (Vo / 4.5 × 10 ³ ) A when the accelerating voltage in FIG.
Provided is an electron beam device, wherein an electric current is passed through the electron gun so that the electric current is equal to or higher than / cm ² sr.

According to a second aspect of the present invention, the shape of the cathode is part of a spherical surface having a curvature of 27 μm or less. In the invention of claim 3, the Vo is 4.5 kV, the brightness of the electron gun is 1 × 10 ⁶ A / cm ² sr or more, and the crossover created by the electron gun is closer to the sample side than the anode. It is formed.

The invention of claim 4 is characterized in that the primary electron beam emitted from the electron gun is irradiated onto the shaping aperture plate to form an image of the shaping aperture plate on the surface of the sample. According to a fifth aspect of the present invention, an electron gun having a thermionic emission cathode, a Wehnelt and an anode is operated under a space charge limiting condition, so that the electron gun is operated at a higher brightness than under a temperature limiting condition. Wire device.

According to a sixth aspect of the present invention, there is provided an electron beam apparatus including an electron gun having a cathode having a plurality of electron emission regions and a Wehnelt and an anode, wherein primary electrons emitted from each of the electron emission regions. A position where a line forms a crossover image formed by an optical system having a condenser lens and a reduction lens in the aperture of the shaping aperture plate, and the principal ray of the electron beam emitted from the center of the electron emission region intersects the optical axis. An electron beam device, characterized in that an NA aperture plate is arranged in the.

According to a seventh aspect of the present invention, there is provided an electron beam device comprising a cathode having a base portion and an electron-emitting material which is continuous with the base portion and has a diameter larger than that of the base portion. Provided is an electron beam apparatus comprising a heating heater provided so as to be in direct contact with the surface on the base side.

The invention of claim 8 is characterized by comprising an axis aligning device for adjusting the positions of the cathode, the Wehnelt, and the anode. According to a ninth aspect of the present invention, there is provided a cathode in which a ridge-shaped projection is formed in an annular shape on an electron emission surface, a Wehnelt having a plurality of small openings provided on a circumference corresponding to the circle, and an anode. An electron beam apparatus is provided in which the center of each of the small openings corresponds to the apex of the protrusion in position.

According to a tenth aspect of the present invention, there is provided an electron beam apparatus including an electron gun having a cathode, a Wehnelt and an anode, wherein the voltage applied to the Wehnelt or the current passed through the electron gun is adjusted to adjust the electron gun. The electron beam device is characterized in that the operating point at which the electron gun operates in the space charge limited region is selected and the brightness is maximum.

An eleventh aspect of the present invention is an electron beam apparatus including an electron gun having a cathode, a Wehnelt, and an anode, wherein spherical aberration created by a convex lens formed by an electric field around the cathode and the Wehnelt is: There is provided an electron beam device characterized in that it is substantially canceled by a negative spherical aberration due to the concave lens action due to the space charge effect and the concave lens action due to the hole of the anode.

According to a twelfth aspect of the present invention, there is provided an electron beam apparatus including an electron gun having a cathode made of LaB6 which operates under a space charge limiting condition, wherein the electron gun has an acceleration voltage of Vo. Brightness of 1 × 10 ⁶ × (Vo / 45
00) An electron beam device characterized by having A / cm ² sr or more.

According to the invention of claim 13, the Vo is 4.5 k.
It is characterized by being V. A fourteenth aspect of the present invention provides a semiconductor device manufacturing method, characterized in that an electron beam apparatus according to any one of the first to thirteenth aspects is used to evaluate a sample during a process.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Some embodiments of an electron beam apparatus according to the present invention will be described below with reference to FIGS. 1 (a) and 1 (b) are diagrams schematically showing a configuration of a first embodiment of an electron beam apparatus according to the present invention, in which an electron gun cathode 1 is made of LaB ₆ single crystal, The radius of curvature of the tip is 15 μm. The coaxiality between the Wehnelt 2 and the anode 3 can be adjusted by a mechanical alignment device 4 from outside a vacuum lens barrel (not shown) while observing the beam from the electron gun.

The anode 3 has a hole with a diameter of 4 μm or less, and the concave lens action of this hole can cancel the spherical aberration caused by the convex lens action formed by the cathode 1 and the Wehnelt 2. It is considered that this is because the primary electron beam emitted from the cathode 1 forms a crossover having a small size. In fact, when a simulation was performed, it was when the crossover 5 was formed on the sample side of the anode 3 that a high brightness of 1 × 10 ⁶ A / cm ² sr or more was obtained. Generally, when the acceleration voltage of the electron gun is Vo, the brightness of the electron gun is 1 × 10 ⁶ × (Vo / 4
500) A / cm ² sr or more.

A shaped beam is used so that the high-intensity beam produced by this electron gun is effectively used. That is, the primary electron beam diverging from the crossover 5 is transferred to the condenser lens 6
Then, the crossover image 9 is formed in front of the reduction lens 7 and at the aperture position of the NA aperture plate 8. A square shaped aperture plate 10 is provided on the sample side of the condenser lens 6 so that only a high-luminance beam near the optical axis passes through. A reduced image of the shaping aperture plate 10 is formed on the surface of the sample 12 by the reduction lens 7 and the objective lens 11.

In order to scan the surface of the sample 12 with the primary electron beam, the deflector 1 is provided between the reduction lens 7 and the objective lens 11.
3, 14 are provided. The deflector 14 is an electromagnetic deflector that directs the primary electron beam traveling along the trajectory 15 to the optical axis L.
The position 16 slightly away from the optical axis L is scanned in the x direction as shown in FIG. As a result, the secondary electron beam emitted from the sample 12 by the scanning of the primary electron beam is deflected by the deflector 14 in the direction opposite to the primary electron beam so as to pass through the trajectory 17,
The secondary electron beam can be separated from the primary electron beam, so that the secondary electron beam can be detected by the detector 18.

FIG. 2 shows the results of changing the electron gun current.
3 is a graph showing the results of simulating the brightness of the electron gun shown in FIG. In FIG. 2, the curve 21
Shows the case where the distance between the cathode 1 and the anode 3 is 5.5 mm, and the curve 22 shows the case where the distance is 3.5 mm. In this simulation, the radius of curvature of the cathode is 20 μm, the diameter of Wehnelt is 1.6 mm,
The distance between the cathode and the Wehnelt cathode side is 0.
2 mm, the Wehnelt thickness is 02. mm, the diameter of the anode is 1.6 mm, and the anode voltage is 4.5 kV.

The curve 21 shows that when the electron gun current is within the range 23, a brightness of 1 × 10 ⁶ A / cm ² sr or more can be obtained. This range 23 is a region where the electron gun current is smaller than the temperature limiting region 24 by almost one digit, and is a complete space charge limiting region. On the other hand, when the distance between the cathode 1 and the anode 3 is 3.5 mm, which is a standard value at an acceleration voltage of 4.5 kV, the brightness is 1 × 10 ⁶ A / cm ² sr as shown by the curve 22. The electron gun current that exceeds the limit is limited to a very narrow range. Therefore, it is understood from this simulation result that the distance between the cathode and the anode should be a large value of 5 mm or more.

As mentioned above, the simulations which gave the results shown in FIG. 2 were carried out with an anode voltage of 4.5 kV. In general, the brightness of an electron gun is proportional to the acceleration voltage, so the brightness when the anode voltage is 4.5 kV is 1
Assuming × 10 ⁶ A / cm ² sr, the luminance when the anode voltage is 20 kV is

[0029]

## EQU1 ## 1 × 10 ⁶ × (20 / 4.5) = 4.4 × 10 ⁶ (A / cm ² sr) (1) Thus, at a general acceleration voltage V, the brightness is

[0030]

[Expression 2] 1 × 10 ⁶ × [V / (4.5 × 10 ³ )] (A / cm ² sr) (2) Therefore, it may be designed so as to have a brightness larger than the value represented by the formula (2).

As shown in FIG. 2, when the electron gun current is increased, the brightness is once increased and then is extremely decreased only when the radius of curvature of the cathode 1 is 27 μm or less. It was

FIG. 3 schematically shows the configuration of the second embodiment of the electron beam apparatus according to the present invention, and is for performing lithography with a high-intensity electron gun. In this embodiment, the electron gun has a radius of curvature of 27 μm and La
B6 cathode 31 and cathode heating heater 32
, Support mechanism 33, Wehnelt 34, and anode 3
5 and an alignment device 36. Support mechanism 33
Is for supporting the cathode 1 and the heater 32 for heating the cathode, and the axis aligning device 36 is means provided for adjusting the axes of the cathode 31, the Wehnelt 34, and the anode 35, and is, for example, a screw. .

The primary electron beam emitted from this electron gun is
Square aperture plate 38 converged by condenser lens 37
Irradiate. The image of the square aperture plate 38 is formed on the mask 40 by the objective lens 39. Further, the electron gun crossover is imaged on the NA aperture plate 41, thereby satisfying the Koehler illumination condition. Two stages of deflectors 43 and 44 are provided in order to scan the mask 40 with the primary electron beam and expose the sample 42 under the mask 40 only in the area of one chip. Since a large current density can be obtained by using the electron beam apparatus shown in FIG. 3, the exposure can be completed in an actual exposure time that is one digit or more shorter than the conventional one.

FIG. 4 is a diagram schematically showing an optical system in the third embodiment of the electron beam apparatus according to the present invention. The electron gun includes a cathode 51, a Wehnelt 52 and an anode 5.
3 is provided. The electron gun has a plurality of electron emission regions arranged on the circumference centered on the optical axis L, and the primary electron beam emitted parallel to the optical axis L from one of these electron emission regions. Is the main beam (indicated by the thin solid line). This allows the electron gun to emit multiple beams.
The structures of the cathode 51 and the Wehnelt 52 of the electron gun will be described later with reference to FIGS.

The main beam emitted from the cathode 51 is converged by the condenser lens 54 and the first crossover 5
5, and a second crossover 58 is formed on the NA aperture plate 57 by the condenser lens 56. After that, the main beam is reduced by the reduction lens 59 to form a third crossover 61 immediately above the objective lens 60.

On the other hand, the primary electron beams (shown by dotted lines) diverging from the individual electron beam emission regions form the first crossover 62 near the anode 53, and the individual crossover 62 is formed by the condenser lenses 54 and 56. And a magnified image 64 of the crossover is formed on the shaping aperture plate 63. Therefore, the shaping aperture plate 63 is critically illuminated. The primary electron beam squared by the shaping aperture plate 63 is reduced by the reduction lens 59 and crossed over.
5 is formed and further reduced by the objective lens 60 to form the probe 67 on the sample 66. The positions 62, 64, and 65 where the primary electron beam forms a crossover can be adjusted to arbitrary positions by adjusting the Wehnelt voltage.

The secondary electron beam emitted from the sample 66 is E ×
It is separated from the optical axis L by the B separator 68, and the lens 69
Is detected by the secondary electron detector 70 via The lens 69 need not be provided depending on the position of the secondary electron detector 70.

As described above, since the main beam in each electron emission region forms the crossover 58 on the NA aperture plate 57, the intensity change between multi-beams is caused by the NA aperture plate 5.
Nothing happens in 7. Moreover, since the crossover 58 is formed in the NA aperture plate 57, the Koehler illumination condition is satisfied.

5 (a) and 5 (b) are enlarged views showing details of the structures of the cathode 51 and the Wehnelt 52 of the electron gun used in the electron beam apparatus shown in FIG. 4, and FIG. A sectional view, (b) is a view of the Wehnelt 52 as seen from the electron optical system side. As shown in (a), the cathode 51 is made of LaB ₆ , and has a disk-shaped electron-emitting portion 511 and a base portion 512 formed by removing a cylinder from both sides so as to have two parallel side surfaces facing each other. And have. In order to efficiently heat the cathode 51, a graphite heater 81 is brought into contact with the parallel side surfaces of the base portion 512 and the base-side surface 513 of the electron emission portion 511. In fact, when the heater 81 was separated from the outer surface of the cathode 51, a heater input of 90 W was required, but when the heater 81 was brought into contact with the outer surface of the cathode 51, the heater input of 50 W heated the heater 81 to the required temperature. We were able to.

Further, a holding metal fitting 82 is provided on the outer periphery of the heater 81.
Is provided and the heater 81 is pressed against the cathode 51 by the pressing metal fitting 82. Thereby, the cathode 51 can be stably heated.

The surface 51 of the electron-emitting portion 511 on the base side.
Since 3 is only in contact with the heater 81, temperature change may occur, but when the stability of the electron gun current was measured, it was found to be within ± 0.2%, It became clear that there was no problem.

FIG. 5B shows the relationship between the Wehnelt 52 and the electron emission region provided on the surface of the electron emission portion 511 opposite to the base portion 512, that is, the electron emission surface 514. That is, on the electron emission surface 514 of the cathode 51, a ridge-shaped protrusion 515 formed along a circle centered on the optical axis L is formed. On the other hand, on the surface 521 of the Wehnelt 52 facing the electron emission surface 514, the ridge-shaped projection 51 is formed.
A plurality of (18 in the figure) small openings 522 are formed at predetermined intervals on the circumference corresponding to No. 5, and the peripheral portion of each opening 522 is made of a thin metal having a thickness of 100 μm or less.
As can be seen from the figure, FIG. 5A shows a line A passing through the centers of two radially opposed openings 522 in FIG. 5B.
It is sectional drawing in alignment with -A.

Assuming that the sample 66 (FIG. 4) is scanned by the primary electron beam in two orthogonal directions x and y, the center of each aperture 522 is a plane parallel to the one scanning direction x including the optical axis L. When projected onto the
The centers of 22 are arranged at equal intervals.

In such a structure, the cathode 51
The electron emission region of is inside the equipotential surface 83 (indicated by dotted lines in FIGS. 5A and 5B) determined by the distance between the cathode 51 and the Wehnelt 52 and the diameter of the opening 522 formed in the Wehnelt 52. It is limited to a part of the protrusion 515, that is, a ridge-shaped ridge line 84 (shown by a thick solid line in FIG. 5B). In other words, the primary electron beam is emitted from the ridgeline 84. The density of the electric current emitted from the central portion of the ridgeline 84 is the highest.

Here, the cathode 51 and the Wehnelt 52
Consider the case where the positions of and shift. First, the cathode 51
Even if the positions of the Wehnelt 52 and the Wehnelt 52 deviate in the direction parallel to the optical axis L, that is, the θ direction, no influence occurs.

Next, when the positions of the cathode 51 and the Wehnelt 52 are displaced in the x direction and / or the y direction, a relative displacement is generated between the equipotential surface 83 and the ridge line 84. First, when a relative positional change between the cathode 51 and the Wehnelt 52 occurs in a direction parallel to the ridge line 84,
Since the overlap between the equipotential surface 83 and the ridgeline 84 does not change,
There is no effect at this time. However, when a relative displacement between the cathode 51 and the Wehnelt 52 occurs in a direction perpendicular to the ridge line 84, the ridge line 84 entering the equipotential surface 83.
The length of is different. However, it can be said that the effect is small while the deviation is small.

As can be seen from FIG. 5B, when the thickness of the Wehnelt 52 is reduced, the distance from the cathode 51 is reduced, and the diameter of each opening 522 is reduced, a circle corresponding to the protrusion 515 is obtained. More openings 52 on the circumference
Two can be arranged. That is, the electron gun can emit more primary electron beams. As a result, the openings 522 approach each other, but such approaching openings can be formed by using a processing method such as etching or electric discharge machining in which no force is applied.

Note that instead of the circular opening 522, as shown in FIG.
As shown in (c) of FIG. 5, an opening 522 ′ having a shape surrounded by an arc and a parallel line perpendicular to the ridgeline 84 may be adopted.
At this time, the tolerance for the positional deviation between the cathode 51 and the Wehnelt 52 is further increased.

FIG. 6 simulates the relationship between the electron gun current (horizontal axis, unit μm) and luminance (vertical axis, unit A / cm ² sr) in the electron gun of the electron beam apparatus shown in FIGS. 4 and 5. The result is shown. The cathode has a curvature of 15 μmR and is made of LaB6. Wehnelt has a diameter of 1.6
An electrode having a thickness of 0.3 μm and a thickness of 0.3 μm is arranged at a position separated by 0.2 mm from the tip of the cathode to the anode side. In FIG. 6, a curve 91 shows the case where the distance between the cathode and the anode is 5 mm, and a curve 92 shows the case where the same distance is 3 mm. The acceleration voltage is 4.5 kV and the cathode temperature is 1900 ° K.

When the distance between the cathode and the anode for which the curve 91 is obtained is 5 mm, the electron gun current is 10 μm.
From A to 150 μA, the brightness increases rapidly as the electron gun current increases. Electron gun current is 150 μA
, The luminance is 4 × 10 ⁶ A / cm ² s at point 93.
It takes an extremely large value of r when the acceleration voltage is 4.5 kV. Here, the primary electron beam emitted from the cathode is
A crossover is formed 12 mm ahead of the cathode, that is, after passing through the anode. Under this condition, it is clear from this simulation that negative spherical aberration with an absolute value of the spherical aberration (positive value) generated by the electron gun is about the same. It can be said that this negative spherical aberration is caused by the concave lens action of the anode hole and the concave lens action by the space charge effect of the primary electron beam itself. Therefore, in order to obtain a large brightness, the voltage applied to the Wehnelt may be adjusted so that the electron gun current can be obtained.

In the curve 91, the electron gun current is 200 μ
After passing A, the brightness decreases rapidly, and beyond point γ,
The brightness is smaller than 1 × 10 ⁴ A / cm ² sr. However, the brightness starts to increase again from 300μA, and 1000μ
If it exceeds A, although not shown, it will be saturated soon. The saturated area is a temperature limited area and its brightness is 3 × 10.
^{There is 5} A / cm ² sr. In the case of the curve 91, it can be said that when the electron gun current exceeds the point β, it approaches the temperature limited region.

In the simulation shown in FIG. 6, the electron gun current exceeding 1000 μA enters the temperature limit region. Therefore, the range in which the electron gun current is smaller than 200 μA (the region to the left of the alternate long and short dash line in FIG. 6) is the space charge limited region. Although not shown in FIG. 6, in the case of the curve 91, the maximum value of the luminance is 3 × 10 ⁵ A / cm ² sr even in the temperature limited region, so that the electron gun current is 1
At 00 μA or more, higher brightness than that in the temperature limited region can be obtained while operating in the space charge limited region. This is a result different from conventional common sense.

On the other hand, the distance between the cathode and the anode is 3 mm.
In the curve 92 obtained in the above case, the brightness is 4 × 10 ⁶ at the point 94 where the electron gun current is slightly smaller than 200.
It becomes A / cm ² sr, and when the electron gun current exceeds the point α, it approaches the temperature limited region.

The electron beam apparatus shown in FIGS. 1 and 4 can be used in a semiconductor device manufacturing method for evaluating a wafer in the process or a completed wafer. Less than,
A semiconductor device manufacturing method including a general semiconductor device manufacturing method will be described with reference to the flowcharts of FIGS. 7 and 8.

As shown in FIG. 7, the semiconductor device manufacturing method includes a wafer manufacturing step S1 for manufacturing a wafer, a wafer processing step S2 for performing a necessary processing on the wafer, and a mask manufacturing step for manufacturing a mask required for exposure. S3, a chip assembling step S4 in which chips formed on the wafer are cut out one by one and made operable, and
It is roughly divided into a chip inspection process S5 for inspecting a completed chip, and each of these processes includes some sub-processes.

Among the above-mentioned steps, the step which has a decisive influence on the manufacture of the semiconductor device is the wafer processing step S2. This is because, in this step, the designed circuit pattern is formed on the wafer, and a large number of chips that operate as memories and MPUs are formed. As described above, it is important to evaluate the processing state of the wafer in the sub-process executed in the wafer processing step S2 that greatly affects the manufacturing of the semiconductor device, and the sub-process will be described below.

First, a dielectric thin film that serves as an insulating layer is formed, and a metal thin film that forms a wiring portion and an electrode portion is formed. The thin film formation is performed by CVD, sputtering, or the like. Then, the formed dielectric thin film and metal thin film, and the wafer substrate are oxidized, and a resist pattern is formed in a lithography process using the mask or reticle created in the mask manufacturing process S3. And by dry etching technology etc.
The substrate is processed according to the resist pattern and ions and impurities are implanted. Then, the resist layer is peeled off and the wafer is inspected.

The wafer processing step S2 as described above is repeatedly carried out by the required number of layers to form a wafer before being separated into chips in the chip assembling step S4.

FIG. 8 is a flowchart showing a lithography process which is a sub-process of the wafer processing process S2 shown in FIG. As shown in FIG. 13, the lithography process includes a resist coating process S21, an exposure process S22, a developing process S23, and an annealing process S24.

In the resist coating step S21, CVD
A resist is applied onto the wafer on which the circuit pattern has been formed by sputtering or the like, and the applied resist is exposed in the exposure step S22. Then, in the developing step S23, the exposed resist is developed to obtain a resist pattern, and in the annealing step S24, the developed resist pattern is annealed to be stabilized. These steps S21 to S24 are repeatedly executed by the required number of layers.

In such a semiconductor device manufacturing method, by using the electron beam apparatus in the chip inspection step S5 for inspecting a completed chip, distortion, blurring, etc. are reduced even in a semiconductor device having a fine pattern. Since it is possible to obtain a clear image, it is possible to reliably detect defects in the wafer.

[0062]

As described above with reference to the drawings, the present invention has the following unique effects.

1. Even when the accelerating voltage of the electron gun is 4.5 kV, a luminance about 3 times higher than the luminance of 3 × 10 ⁵ A / cm ² sr in the temperature limited area can be obtained in the space charge limited area. 2. Since the distance between the cathode and the anode can be increased by 5 mm or more, discharge is unlikely to occur between the cathode and the anode.

3. Electron gun current is 100μA to 400μ
Since it is as small as A, the electron gun power supply can be simplified. 4. Shot noise is small because the electron gun is operated under the space charge limiting condition.

5. The sample is scanned by the shaped beam,
Since the magnified image of the crossover is formed on the NA aperture plate, the advantage of the small size of the crossover can be utilized, and a primary electron beam of large current can be obtained.

6. Since the mechanism for aligning the cathode, the Wehnelt, and the anode with each other is provided, the precision of the electron gun can be improved without making an ultra-high precision electron gun.

7. Multibeams can be formed even when the crossover positions formed by the individual multibeams and the positions at which the chief rays of the respective multibeams intersect are different.

8. Since the cathode is in the form of a direct heating disk, the cathode can be heated to a required temperature with a small heating power. 9. Under the space charge limiting condition, a higher intensity primary electron beam than under the temperature limiting condition can be obtained.

10. It is possible to provide a semiconductor device manufacturing method with a high yield.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a first embodiment of an electron beam apparatus according to the present invention.

FIG. 2 is a graph showing a result of a simulation performed using the electron beam apparatus shown in FIG.

FIG. 3 is a diagram schematically showing a second embodiment of an electron beam apparatus according to the present invention.

FIG. 4 is a diagram schematically showing a third embodiment of an electron beam apparatus according to the present invention.

5A is a cross-sectional view showing in detail a structure of a cathode of an electron gun in the electron beam apparatus shown in FIG. 4, and FIG. 5B is a view explaining a relationship between an electron emission region of the cathode and an opening of Wehnelt; (C) is a figure which shows the other example of the opening of Wehnelt.

6 is a diagram showing a result of simulating the operation of the electron beam apparatus shown in FIG.

FIG. 7 is a flowchart of a method for manufacturing a semiconductor device by applying the electron beam apparatus according to the present invention.

8 is a flowchart showing a lithography process which is a sub-process of the wafer processing process in FIG.

[Explanation of symbols]

1: cathode, 2: Wehnelt, 3: anode,
4: mechanical alignment device, 5, 9: crossover, 6: condenser lens, 7: reduction lens,
8: NA aperture plate, 10: Molded aperture plate, 11: Objective lens, 12: Sample, 13, 14: Deflector, 15,
17: orbit, 18: detector, 31: cathode, 3
2: heater, 33: support fitting, 34: Wehnelt, 35: anode, 36: mechanical alignment device,
37: Condenser lens, 38: Square aperture plate,
39: Objective lens, 40: Mask, 41: NA aperture plate, 42: Sample, 43, 44: Deflector, 51: Cathode, 52: Wehnelt, 53: Anode,
54, 56: Condenser lens, 55, 58, 6
1, 62, 65: Crossover, 57: NA aperture plate, 59: Reduction lens, 60: Objective lens, 6
3: Molded aperture plate, 66: Sample, 67: Probe,
68: E × B separator, 69: Lens, 70: Secondary electron detector, 511: Electron emission part, 512: Base part, 51
4: electron emission surface, 515: protrusion, 522, 52
2 ': opening, 81: heater, 82: press fitting,
83: equipotential surface, 84: ridge line,

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/027 H01L 21/66 J 21/66 21/30 541B 541A F term (reference) 2H097 AA03 BB03 CA16 EA01 LA10 4M106 AA01 BA02 CA38 DB30 5C030 AA01 AA06 AB02 BB03 BB04 BB05 BC02 BC06 5C033 JJ07 5F056 EA02 EA05

Claims (14)

[Claims] 1. An electron beam apparatus including an electron gun having a thermionic emission cathode, a Wehnelt, and an anode, wherein an acceleration voltage in the electron gun is Vo volts.
Brightness is 1 × 10 ⁶ × (Vo / 4.5 × 10 ³ ) A / cm ²
An electron beam apparatus, wherein an electric current is passed through the electron gun so as to be sr or more. 2. The electron beam apparatus according to claim 1, wherein the cathode has a part of a spherical surface having a curvature of 27 μm or less. 3. The electron beam apparatus according to claim 1, wherein the Vo is 4.5 kV, the brightness of the electron gun is 1 × 10 ⁶ A / cm ² sr or more, and the electron gun produces the electron beam. An electron beam apparatus, wherein a crossover is formed on the sample side of the anode. 4. The electron beam apparatus according to claim 3, wherein a primary electron beam emitted from the electron gun is irradiated onto the shaping aperture plate, and an image of the shaping aperture plate is formed on the surface of the sample. An electron beam device characterized by: 5. An electron beam apparatus characterized in that an electron gun having a thermionic emission cathode, a Wehnelt and an anode is operated under a space charge limiting condition, so that the electron gun is operated at a higher brightness than under a temperature limiting condition. . 6. An electron beam apparatus comprising a cathode having a plurality of electron emission regions, and an electron gun having a Wehnelt and an anode, wherein primary electron beams emitted from the respective electron emission regions are condenser lenses. And a crossover image formed by an optical system having a reduction lens is formed in the aperture of the shaping aperture plate, and the NA aperture plate is provided at a position where the principal ray of the electron beam emitted from the center of the electron emission region intersects the optical axis. An electron beam device characterized by being arranged. 7. An electron beam apparatus, comprising: a cathode; and a cathode having a base and an electron-emitting material connected to the base and having a diameter larger than that of the base, the surface of the base and the electron-emitting material on the side of the base. An electron beam apparatus comprising a heating heater provided so as to be in direct contact with the electron beam apparatus. 8. The electron beam apparatus according to claim 1, further comprising an axis alignment device for adjusting the positions of the cathode, the Wehnelt, and the anode. 9. A cathode having a ridge-shaped projection formed in an annular shape on an electron emission surface, a Wehnelt having a plurality of small openings provided on a circumference corresponding to the circle, and an anode. An electron beam apparatus, wherein the center of each of the small openings corresponds in position to the apex of the protrusion. 10. An electron beam apparatus comprising an electron gun having a cathode, a Wehnelt, and an anode, wherein the voltage applied to the Wehnelt or the current passed through the electron gun is adjusted to maximize the brightness of the electron gun. An electron beam apparatus, wherein an operating point at which the electron gun operates in a space charge limited region is selected. 11. An electron beam apparatus including an electron gun having a cathode, a Wehnelt, and an anode, wherein a spherical aberration created by a convex lens formed by an electric field around the cathode and the Wehnelt is a concave lens due to a space charge effect. An electron beam device which is substantially canceled by a negative spherical aberration caused by the action and the concave lens action by the hole of the anode. 12. A LaB6 operating under a space charge limiting condition.
An electron beam apparatus including an electron gun having a cathode made of, wherein the brightness of the electron gun is 1 × 10 ⁶ × (Vo / 4500) A / cm ² sr when an acceleration voltage of the electron gun is Vo. An electron beam apparatus characterized by the above. 13. The electron beam apparatus according to claim 12, wherein the Vo is 4.5 kV. 14. A method of manufacturing a semiconductor device, wherein the electron beam apparatus according to any one of claims 1 to 13 is used to evaluate a sample during a process.