JPS63269521A - Electron beam lithography equipment - Google Patents

Abstract

PURPOSE:To increase a drawing speed and to make a fine change of a drawing size by a method wherein two or more electron sources are arranged unidimensionally at prescribed intervals and an object where a pattern is to be drawn is shifted relatively at a prescribed angle with reference to an electron source row. CONSTITUTION:Electron sources 2 are arranged in such a way that, when a wafer 1 is shifted in an X-axis direction at uniform speed, an angle formed by a unidimensionally arranged direction of the electron sources 2 with reference to the X-axis direction, i.e. a moving direction of the wafer 1 is theta. This angle theta is theta=sin<-1>(d/ D) if a width of an electron discharge region of the electron sources 2 is d and an interval between the individual electron sources is D. A pattern is formed in such a way that an electron is emitted from the individual electron sources 2 while the wafer 1 is being shifted in this manner. If the time when a picture element 25 reaches a part directly under an electron emission part EB3 is designated as t5, a pattern P is drawn by emitting the electron from an EB1 during the time t1-t3, from an EB2 at the time t4 and from an EB3 at the time t5. If the angle theta is set at a value thetaM=sin<-1>(d/kD) which is smaller than sin<-1>(d/D) (where k>1), it is possible to magnify the pattern k times without isolating individual dots by changing the angle theta from thetaM to, e.g., thetaL=sin<-1>(d/D).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electron beam lithography apparatus that has a plurality of electron sources, can perform high-speed lithography, and can also change the lithography magnification.

[Prior Art] Conventionally, in an electron beam lithography system, lithography is performed using a single electron source, and the electron source includes tungsten, tungsten,
A field emission type or a thermal field emission type using a material such as LaB is typical.

[Problems to be Solved by the Invention] However, according to the above-mentioned conventional example, the drawing speed is slow because drawing is performed using a single electron source, and the size of the electron source is large, so multiple electron sources are arranged. The problem is that it is difficult to That is, although there is a demand for an improvement in drawing speed, there is a problem in that it is difficult to achieve this.

Furthermore, with the recent trend toward higher integration, minute expansion and contraction of wafers cannot be ignored, and a simple method for correcting this is desired.

SUMMARY OF THE INVENTION In view of the problems of the prior art, it is an object of the present invention to provide a simple and low-cost electron beam lithography system that has a high lithography speed and allows minute changes in the lithography size.

[Means and operations for solving the problems] In order to achieve the above object, the electron beam lithography apparatus of the present invention includes at least one electron source array in which a plurality of electron sources are arranged one-dimensionally at predetermined intervals; means for controlling the output timing of the electron beam from the electron source; means for moving an object on which a pattern is drawn by the electron beam output from the electron source relative to the electron source array while maintaining a predetermined angle; means for changing the drawing magnification by adjusting the angle and the electron beam output timing and/or the relative movement speed, and the pixel distribution in the direction of the relative movement is controlled by the electron beam output timing and the movement by the timing control means. The pixel distribution in the direction perpendicular to the direction of the relative movement is determined by the relative movement speed of the means, and the pixel distribution in the direction perpendicular to the direction of the relative movement is determined by the distance between each electron source arranged in the electron source body and the size of the electron emission part of each electron source. It is determined by the height and the above-mentioned predetermined angle. Therefore, by changing the predetermined angle, electron beam output timing, and/or relative movement speed, the writing magnification can be changed.

Furthermore, by determining the predetermined angle in consideration of the size of the electron emission area of the electron source and the spacing between each electron source, it is also possible to distribute the pixels without gaps in the direction perpendicular to the above-mentioned relative movement direction. Therefore, by suitably controlling the output timing, a continuous straight line can be drawn not only in the direction of relative movement but also in the direction perpendicular to this direction.

[Example] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a plan view showing the positional relationship between a wafer and a plurality of electron sources when the electron beam lithography apparatus according to the first embodiment of the present invention is applied to pattern lithography of semiconductor elements. . In the figure, 1 is a wafer, 2 is an electron source (electron-emitting device)
It is. A plurality of electron sources 2 are arranged one-dimensionally to form an electron source row.

In this configuration, in order to draw the pattern 3 on the wafer 1, the wafer 1 is moved at a constant speed in the X-axis direction. At this time, the electron sources 2 are arranged so that the angle between the one-dimensional arrangement direction of the electron sources 2 and the X-axis direction, that is, the moving direction of the wafer 1 is θ. This angle θ is as follows, where d is the width of the electron emission region of the electron source 2 and D is the interval between each electron source. Then, by moving the wafer 1 in this manner and emitting electrons from each electron source 2 at a desired timing, a pattern as shown in the figure is formed. The timing of electron emission can be determined in the same manner as described in Examples 2 and 3 below.

FIG. 2 is a side view showing the positional relationship between the electron source 2 and the wafer 1 when viewed from the side. In the figure, l is a wafer, 2 is an electron source, 4 is an electron emission area, 5 is an electron emitted from the electron emission part, PM is a pulse motor, ST is a wafer stage, SD is a wafer stage driver, and 100 is a CPU. .

As shown in the figure, since the electron source 2 is provided close to or in close contact with the wafer 1, the size of the pixel of the pattern 3 formed as described above is
will be approximately the same size.

Therefore, since the electron sources 2 are arranged as shown in equation (1) above, there is a gap between the line drawn by one electron source 2 and the line drawn by the electron source 2 next to that electron source. do not have. Furthermore, as explained above, between the electron source 2 and the wafer 1, there is no need for the electron lens, deflection electrode, etc. that were conventionally required, and the structure is not only simple, but also Eliminates electron beam loss,
The efficiency of using electron beams has improved several ten times compared to the conventional method.

FIG. 3 is a perspective view showing the plurality of electron sources 2 of FIG. 1 and their driving circuits. In the same figure, 6 is the drive circuit main body, 7.8 is a bonding pad part, and 9 is an n-type S
i layer (n-5t layer), 10 is a p''-5i substrate, 11 is an ohmic electrode provided on the surface of the n-type Si layer 9 to apply a reverse voltage to the pn junction, 12 is a p''-5i substrate 10 is an ohmic electrode provided on the entire back surface, 13 is a trench for element isolation, 14 is a Sin layer, and 15 is an electrode provided on the surface of the Sin layer 14, which is an insulating layer. 16
is an electron emitting part, and the Sin2 layer 14 and the electrode layer 15 are n-
C in the hole made by etching up to layer 9 of 5i.
A low work function material such as s-0, CsSi, etc. is provided.

Next, the operation of this electron-emitting device (electron source) will be explained.

When a reverse voltage is applied between the p'''-5i substrate 10 and the n-type Si layer 9 provided thereon via the electrode 12 and the electric field f!11, energy higher than that in the thermal equilibrium state is generated due to the avalanche effect. Electrons are generated with n-type semiconductor (n-5t
The voltage of the electrode 15 provided on the layer 9) is changed to
When set to a value more positive than the voltage applied to the n-type region, the high-energy electrons generated in the n-type region pass through the low work function material provided in the electron emitting section 16 and are emitted into vacuum.

At this time, since each element is separated by the groove 13,
Each element can be driven independently by the voltage applied to the electrode 11. Therefore, the extraction electrode 15 may be common to each element, and there is no need to provide a complicated electrode structure around the electron emitting section 16, so the electron emitting section 16 can be processed to a diameter of 0.25 μm.

However, the size of the electrode for connection with the drive circuit section 6 is several μm.
Since this would be difficult to manufacture, the distance between each electron source was set to 10 μm. The power source (not shown) that applies a predetermined voltage to each electrode is the CP
The operation is controlled by U 100.

Therefore, the angle θ between the moving direction of the wafer 1 and the one-dimensional arrangement direction of the electron sources 2 is 1.43° from the above equation (1). This angle is measured by a rotary encoder, and based on this measurement information, the CPU 100 controls a pulse motor PM provided above the electron source, and sets the electron source by driving the pulse motor PM to rotate the electron source by a predetermined angle. .

Note that CPU 100 also controls the movement of wafer stage ST via stage driver SD.

Next, a method for finely adjusting the drawing size will be explained.

The component in the Y-axis direction in FIG. 1, ie, the direction perpendicular to the feeding direction of the wafer 1, is enlarged or reduced by finely adjusting the angle θ formed by the arrangement direction of the electron sources 2 with respect to the X-axis.

Here, when this angle θ is as in equation (1) above, the pattern drawn by the electron beam becomes as shown in FIG. 8(a). Therefore, if the angle is larger than θ, the dots will be separated as shown in FIG. 3(b). Therefore, to avoid this, the angle θ is 5in-' (d/D)
Set it to a value smaller than (standard value).

That is, for example, if the reference θ is set to θ2, which is expressed by k>1, then the interval between the dots is d/, so the angle θ is changed from 02 to, for example, θ = sin-'( -), the dot spacing becomes d, and each dot can be enlarged twice without separating. Further, if the angle θ is θ, =ssn-' (-=-) D However, if k'> k > 1, it is possible to reduce the value by a factor of 'k/'.

On the other hand, the expansion of the X-axis direction component, which is the feeding direction of wafer 1,
The reduction is preferably performed by finely adjusting the timing of electron emission from each electron source 2 and/or the feeding speed V of the wafer 1, taking into account the error caused by finely adjusting the angle θ.

In this case, as in the case of the Y-axis direction, when the clock pulse t is 1=-2, the dots are drawn so as to be in contact with each other as shown in FIG. 8(C). If the drawing speed is increased from V to V+Δ■ while maintaining this clock pulse, the dots will separate as shown in FIG. 2(d), and a continuous line cannot be drawn. Therefore, if the reference clock is set to tM, where k>1, and the dot spacing is set to d/k, for example, the clock can be slowed down by multiplying by , or the wafer speed V
By multiplying the dots by 1/1 to slow down the dots, it is possible to enlarge the dots by a factor of 1 in the x-axis direction without separating them. Also, the clock can be accelerated by multiplying the reference value tii by /, or the wafer speed can be accelerated by multiplying by / by 1! +=.

v However, k’　　　　　k＞1 Then, it can be reduced to k/'.

The electron-emitting device used in this example was disclosed in U.S. Patent No. 42596.
As disclosed in No. 78, a pn junction is created using SI and a reverse voltage is applied to it to generate electrons with higher energy than in a thermal equilibrium state due to the avalanche effect, thereby realizing electron beam emission into a vacuum. However, the present invention is not limited to this, and other electron sources may be used as long as they can be miniaturized or integrated.

As such an element, for example, Japanese Patent Publication No. 54-302
As disclosed in Japanese Patent No. 74, pn consisting of AlXGa+-xP (0≦X≦1) is formed on a GaP semiconductor substrate.
A method in which a junction region is provided, a forward voltage is applied to the pn junction region, and electrons injected from the n region to the p region are taken out from a low work function material provided on the surface of the p region, and N has a wide band gap. An Npn junction is formed using a p-type semiconductor and a p-type semiconductor and an n-type semiconductor having a narrow band gap, and electrons are injected from the n-type semiconductor into the p-type semiconductor, and the electrons are accelerated in the pn region to which a reverse voltage is applied to create a vacuum. N that emits electrons or has a wide bandgap
A type semiconductor and a p-type semiconductor having a narrow band gap may be bonded to each other, and electrons injected from the N region to the p region can be taken out from a low work function material provided on the surface of the p region.

Furthermore, in this example, the configuration does not use an electrostatic lens, but according to this method, the distance between each electron emitting part can be increased, so a configuration in which an electrostatic lens or deflection electrode is provided is also possible. There is an advantage to having one.

Next, an electron beam lithography apparatus according to a second embodiment of the present invention will be explained with reference to FIGS. 4 and 5.

In the first embodiment, as shown in FIG.
is circular. Therefore, if the electron source array arranged in the − dimension is provided at an angle θ with respect to the moving direction X toward the cube as shown in FIG. The pattern of lines parallel to the X-axis and lines parallel to the Y-axis on the wafer 1 is as shown in FIG. 4(a), and there is a problem that a straight pattern cannot be drawn. In the second embodiment, this problem is solved and it is possible to draw a straight line pattern as shown in FIG. 4(b).

FIG. 5 shows a one-dimensional array of electron sources that realizes this.

In the figure, 20 is the main body of a plurality of electron sources. EBI, EBB, EBB.

EB4. EB5. EBB is an electron emission part of each electron source, and has a square shape as shown in the figure.

The XY coordinate axes in this figure indicate the coordinate axes of the wafer 1 in FIG. 1, and in this embodiment, the one-dimensional arrangement direction of the electron sources 2 is at an angle θ It's only tilted. The value of the angle θ is similarly given by the above equation (1). However, as can be seen from FIG. 5, one side of each square of the electron emitting section is parallel to the wafer moving direction (X-axis).

The configuration and operation of other parts are the same as in the first embodiment.

However, here, a method for drawing a pattern P consisting of pixels 21 to 25 as shown in FIG. 5 on a sea urchin will be further explained.

First, the wafer is moved at a certain constant speed V in the negative direction of the X axis. Then, the time when the pixel 21 part arrives directly below the electron emission part EBI is jlx, the time when the pixel 22 part arrives directly below the electron emission part EBI is t2, and the electron emission part EBI
t3 is the time when the pixel 23 part arrives directly below the electron emission part EB2, and t is the time when the pixel 24 part arrives directly below the electron emission part EB2.
4. If t is the time when the pixel 25 arrives directly below the electron emission part EB3, then time 1. ．． 1. ．． 13, electrons are emitted from the electron emission section EBI, then at time t4, electrons are emitted from the electron emission section EB2, and then at time t4.
The pattern P can be drawn by emitting electrons from the electron emitting portion EB3 at the time s.

In this case, since each electron emitting section is square and one side of the square is parallel to the direction of movement of the wafer, a straight pattern can be drawn with respect to the X and Y axes.

Embodiment 3 Next, a third embodiment of the present invention will be described using FIG. 5. In the second embodiment described above, the times t, ~t,
The case where electrons are emitted from each electron source is shown as an example, but here, using a similar configuration, the shortest timing interval is used as a clock pulse, and the clock pulse is used to calculate the emission time of each electron source. The method for counting is shown below.

Now, let the feed speed to the query be V, and each electron emission part EBI ~
When the size of the EBB is d and the interval between each electron emission part is D, the shortest timing E min is, however, k≧1, and the general timing 1. However, m, n=o, 1.2, 3. ...D'=D-d
It is k.

In addition, in order to count the general timing t1 using j mIn in equation (2) as a clock pulse, we need , o d -1/k)2=x However, if λ is an integer and the interval between each electron emission part is set to D=d λ + 1/k), then the shortest timing tmln can be used as a clock pulse. General timing 1+ can be counted.

In other words, by employing an electron source structure in which the distance between each electron emitting portion is as described above, driving of the electron component can be simplified.

Embodiment 4 Next, an electron beam lithography apparatus according to a fourth embodiment of the present invention will be described using FIG. 6. The device shown in the figure has at least two electron sources arranged in the negative dimension and arranged in parallel. In the figure, 31 is an electron source array (electron source unit) similar to that in FIG. 3 or 5 in which electron sources are arranged one-dimensionally, and 32 is another electron source unit similar to this.

At the time of drawing, the wafer is fed in the X-axis direction as in the above embodiment. At this time, the electron emitting portions EB11. of the electron source array 31. EB12. EB13. EB14゜EB
Electron emitting parts EB22', EB23', EB24 are arranged in series as an electron source array 32' at the same intervals as 15.
'.

Electron source arrays 31 and 32 are arranged in advance so that patterns 35, 3δ, 37, and 38 that can be drawn if EB25' is provided are drawn.

Here, the lines drawn by the electron emitting portion EB15 of the electron source row 31 and the electron emitting portion EB21 of the electron source row 32 are the sixth line.
They are set so that they overlap as shown in pattern 34 in the figure. Then, an abutment surface 40 between the electron source array 31 and the electron source array 32
is parallel to each one-dimensionally arranged electron emitting section, so in order to set it as described above, the electron source array 32 must be relatively aligned with the abutting surface 4 as shown by the arrow 33 in FIG.
All you have to do is make it parallel to 0.

By arranging the electron source arrays 31 and 32 in this manner, the electron source array 32 can draw the same line as the electron source array 32', which is a one-dimensional extension of the electron source array 31. In other words, the electron emission parts EB22 to EB25 of the electron source array 32 are the electron emission parts EB22' to EB25 of the electron source array 32', respectively.
Corresponds to 25'. As explained above, <EB15
and EB21 are arranged so as to draw the same line, so the line written by the electron source array 31 and the line written by the electron source array 32 are accurately connected.

When the electron sources are arranged as in this embodiment, the yield of this unit is improved because the number of electron sources included in one unit (here, electron source row 31 and electron source row 32) is small. In addition, there is an advantage that even if one electron emitting unit breaks down, there is no need to replace all the electron sources, and only the faulty unit needs to be replaced.

Embodiment 5 An electron beam lithography apparatus according to a fifth embodiment of the present invention will be described with reference to FIG. This embodiment relates to an electron beam lithography apparatus in which the inclination angle θ of an electron source array with respect to the wafer feeding direction is monitored not by a rotary encoder but by another method. That is, in Example 1, the angle θ was measured by a rotary encoder, but here, as shown in FIG. 5
2 is provided so that the laser beam 54 outputted from the laser unit 51 is reflected by a mirror 53 erected parallel to a reference plane indicating the direction of the wafer 1 and incident on the line sensor 52. The CPU receives the signal from the line sensor 52 and measures the angle θ from the position where the reflected light enters the line sensor 52. At this time, as a reference plane indicating the direction of the wafer 1, for example, a wafer orientation flat can be used.

Moreover, any one of the above-mentioned Examples 1 to 4 may be used as the electron source.

This method has the advantage that it is possible to monitor in real time which direction the electron source array is facing while the wafer is being fed. Therefore, this method is suitable also when it is necessary to change the drawing size in real time as shown in the first embodiment.

[Effects of the Invention] As explained above, according to the present invention, the following effects can be obtained.

(1) Patterns can be drawn using multiple electron sources, so drawing speed is fast.

(2) The magnification of the drawing pattern can be changed simply by adjusting the angle of the electron source array, the electron emission timing, and/or the moving speed of the object 8.

(3) Since multiple electron sources can be placed separately, the heat source is dispersed, so stable drawing is possible, and if necessary, an electron lens etc. can also be placed.

(4) There is no need for an electron lens, deflection electrode, etc. between the electron source and the object to be drawn, which not only simplifies the configuration, but also
Loss of the electron beam at the electrodes and the like is reduced, and electron beam utilization efficiency is high.

(5) If the shape of each electron source is square and one side of the square is parallel to the octagonal direction of the object, a straight line pattern can also be drawn with respect to the X and Y axes.

(6) By setting the size of the electron emitting portions and the spacing between each electron emitting portion as in the present invention, the drive control of the electron source can be easily performed.

(7) By dividing multiple electron sources into several units, even if one electron emitting part breaks down or becomes defective, there is no need to replace all the electron sources, making it possible to eliminate the need to replace the failed unit. All you have to do is replace it.

(8) By using a laser beam and a line sensor, the direction in which the object is sent relative to the electron source can be monitored in real time.

[Brief explanation of the drawing]

1 and 2 are a plan view and a side view, respectively, showing the positional relationship between a plurality of electron sources and a wafer in an electron beam lithography apparatus according to a first embodiment of the present invention, and FIG. FIG. 4 is a perspective view showing the structure of a plurality of electron sources used in the apparatus shown in FIG. 1 and their driving circuits; FIG. The schematic diagram shown in FIG. 5 shows the one-dimensionally arranged electron sources and their electron emitting parts in the electron beam lithography apparatus according to the second embodiment of the present invention, and the arrangement according to the third embodiment of the present invention. FIG. 6 is an explanatory diagram showing a method of arranging a plurality of one-dimensionally arranged electron source arrays in parallel in an electron beam lithography apparatus according to a fourth embodiment of the present invention. , FIG. 7 is a plan view showing a method for monitoring the tilt of the electron source array with respect to the wafer in an electron beam lithography apparatus according to a fifth embodiment of the present invention, and FIG. FIG. 3 is an explanatory diagram for explaining the principle of changing the magnification of a pattern. 1: Wafer, 2: Electron source, 3: Drawing pattern, 4: Electron emission region, 5: Electrons, 6: Drive circuit main body, 7.8: Bonding pad section, 9: N-5T layer, 10: P'' -5i board, 11,
12 Niomic electrode, 13: Groove, 14: 5in2
．． 16, EBI to EB25: Electron emission part, 51: Semiconductor laser with built-in collimating lens, 52 Niline sensor, 5
3: Mirror, 100: CPIJ% PM: Pulse motor, SD: Stage driver, ST: Wafer stage. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Tetsuya Ito [X Figure 1 Figure 2 Figure 3 (b) Figure 4 Figure 6 Figure 7 Figure 8 (b) figure

Claims (1)

[Claims] 1. At least one electron source array in which a plurality of electron sources are arranged one-dimensionally at predetermined intervals; timing control means for controlling the timing of outputting an electron beam from the electron source; a moving means for relatively moving an object on which a pattern is drawn by an electron beam output from a source while maintaining a predetermined angle with respect to the electron source array, and adjusting the predetermined angle, the electron beam output timing and/or the relative movement speed; An electron beam lithography apparatus comprising a magnification changing means for changing the lithography magnification by adjustment. 2. If the size of the electron emitting part of the electron source is d, the predetermined interval is D, and the angle between the one-dimensional arrangement direction and the relative movement direction is θ, then θ=sin^-^ 1(
d/kD) provided that k≧1. 3. The electron beam lithography apparatus according to claim 1, wherein the electron emitting section has a square shape, and the direction of the relative movement is substantially parallel to one side of the square. 4. If the size of the electron emission part of the electron source is d, and the predetermined interval is D, then D=d√{l^2+(1/k)^2}, where l is an integer and k≧1. An electron beam lithography apparatus according to claim 1. 5. If the clock pulse for controlling the timing is t, and the speed of the relative movement is v, then t=d/(kv
) However, the electron beam lithography apparatus according to claim 4, wherein k≧1. 6. The electron beam lithography apparatus according to claim 1, having a plurality of said electron source rows, which are arranged in parallel. 7. A patent claim in which the plurality of electron source arrays are arranged such that a line drawn by at least one electron source in the electron source array overlaps a line drawn by at least one electron source in another electron source array or an extension thereof. The electron beam lithography apparatus according to item 6. 8. The electron beam source main body has a light emitting part and a light receiving line sensor, and the light emitted by the light emitting part is reflected on a surface parallel to a reference plane indicating the direction of the object, and the reflected light is transmitted to the light receiving line sensor. The electron beam lithography apparatus according to claim 1, wherein the change in the predetermined angle is monitored by detecting the change in the predetermined angle.