JPH07220993A - Charged particle beam exposure system - Google Patents

Abstract

(57) [Summary] (Correction) [Objective] To provide a charged particle beam exposure apparatus capable of jumping a beam between subfields with high pattern position accuracy and at high speed. In a charged particle beam exposure apparatus in which a charged particle beam is deflected by an electromagnetic deflector 33 and an electrostatic deflector 34 to draw a pattern, a deflection trajectory of the electromagnetic deflector is corrected, and a control signal is output from the electromagnetic deflector. The correction electromagnetic deflector 71 having a fast response speed to the correction electromagnetic deflector and the control means for controlling the correction electromagnetic deflector are provided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to charged particle beam exposure, and more particularly to deflection of a charged particle beam.

[0002]

2. Description of the Related Art In recent years, ICs have been widely applied to all industries, such as computers, communications, and machine control, as their integration and functions have been improved. For example, in DRAM, 1M, 4M, 16
M, 64M, 256M, 1G and their integration are progressing. Such high integration is solely due to the progress of fine processing technology.

With the increase in the density of such integrated circuits, an exposure apparatus using a charged particle beam such as an electron beam has been developed as a method for forming a fine pattern. In charged particle beam exposure, fine processing of 0.05 μm or less is 0.02 μm
It can be realized with the following alignment accuracy. However, until now, it was thought that the throughput would be too low to be used for mass production of LSI. This is a one-stroke discussion of electron beams, focusing on the physical and technical obstacles to increase throughput,
It is not a result of elucidating the cause and seriously examining it, but merely making a judgment in view of the productivity of the current commercial device.

However, the present inventors invention block exposure or blanking aperture array method using, throughput of about 2 cm ^2/1 sec can now be expected. Its fineness, alignment accuracy, quick turnaround, and reliability are all superior to other methods.

Here, a conventional block exposure type electron beam exposure apparatus which is one of the charged particle beam exposure apparatuses will be described with reference to FIG. The exposure apparatus shown in FIG. 12 is roughly divided into an exposure section 10 and a control section 50. The exposure unit 10 generates an electron beam, shapes the electron beam into a spot shape or a pattern shape, and exposes the exposure target at a desired position. The control unit 50 is a unit that generates a signal that controls the exposure unit 10. Below the exposure unit 10, there is a stage 35 on which an exposure target (sample) W is placed.

First, the exposure section 10 will be described. The electrons generated from the cathode electrode 11 are extracted by the grid electrode 12 and the anode electrode 13. These electrodes 11, 12 and 13 form a charged electron beam generation source 14.

The electron beam generated from the charged electron beam generation source 14 is shaped by, for example, a first slit 15 having a rectangular opening, passes through a first electron lens 16 that focuses the electron beam, and passes through a transmission mask 20. The beam is incident on a slit deflector (deflector) 17 for correcting and deflecting the beam irradiation position. The slit deflector 17 is controlled by the corrected deflection signal S1.

In order to shape the electron beam into a desired pattern, a transmission mask (stencil mask) 20 having a plurality of transmission holes such as a rectangular opening and a block pattern opening of a predetermined pattern is used. The electron beam that has passed through the slit reflector 17 is shaped into a desired pattern through the electron beam shaping unit. The electron beam shaping unit includes a second electron lens 18 and a third electron lens 1 which are provided to face each other.
9. The transmission mask 20 is mounted between these electron lenses so as to be movable in the horizontal direction, and is disposed above and below the transmission mask 20. The transmission mask 20 deflects the electron beam according to the position information P1 to P4, respectively. It includes first through fourth deflectors 21-24 which select one of the upper transmission apertures.

The shaped electron beam is controlled by the blanking electrode 25 to which the blanking signal SB is applied so as to be blocked or pass therethrough. The electron beam that has passed through the blanking electrode 25 receives the fourth electron lens 2
6, the aperture 27, the refocusing coil 28, and the fifth electronic lens 29 to adjust the focus coil 3
It is incident on 0. The focus coil 30 has a function of focusing the electron beam on the exposure target surface. Also,
The Sting coil 31 corrects astigmatism. The electron beam further includes a sixth electron lens 32 and a main deflector (main deflector) 3 which is an electromagnetic deflector for positioning the object W to be exposed according to the exposure position determination signals S2 and S3.
The position is controlled by 3 and a sub-deflector (sub-deflector) 34 which is an electrostatic deflector, and a desired position on the exposure target W is irradiated.

The exposure object W is placed and moved on a stage 35 which is movable in the XY directions. The exposure section 10 is further provided with first to fourth alignment coils 36, 37, 38, 39.

The control unit 50 has a memory 51 and a CPU 52. Design data of the integrated circuit device is stored in the memory 51, read by the CPU 52, and processed. CP
U52 also controls the entire charged electron beam exposure apparatus.

The interface 53 stores, in the data memory 54 and the sequence controller 60, drawing information fetched by the CPU 52, for example, drawing position information on the wafer W on which a pattern is to be drawn and various kinds of information such as mask information of the transparent mask 20. Forward. Data memory 54
Stores and holds the drawing pattern information and the mask information transferred from the interface 53.

The pattern controller 55 receives the drawing pattern information and the mask information from the data memory 54, designates one of the transmission holes of the transmission mask according to the information, and indicates the position of the designated transmission hole on the transmission mask. Generate signals P1-P4. Further, the pattern controller 55 has a designation function, a holding function, a computing function, and an output function that perform various processes including a process of computing a correction value H according to the shape difference between the pattern shape to be drawn and the designated transparent hole shape. Have.

The drive unit 56 has a digital / analog conversion function and an amplification function, receives the correction value H, and generates a corrected deflection signal S1. The mask moving mechanism 57 moves the transparent mask 20 as needed according to a signal from the pattern controller 55. Blanking control circuit 58
Controls the drive unit 59 having a digital / analog conversion function and an amplification function in response to a signal from the pattern controller 55 to generate a blanking signal SB.

The sequence controller 60 receives the drawing position information from the interface section 53 and controls the drawing processing sequence. The stage moving mechanism 61 moves the stage 35 as needed in response to a signal from the sequence controller 60.

The movement of the stage 35 is detected by the laser interferometer 62 and supplied to the deflection control circuit 63. The deflection control circuit 63 calculates the exposure position on the sample (wafer) W and generates the exposure position determination signals S2 and S3 (having a digital-analog converter (DAC) and an amplifier (AMP)). A signal is supplied to 64 and 65, and a signal is also supplied to the sequence controller 60. The drive units 64 and 65 are digital and
It has an analog conversion function and an amplification function.

In ordinary electron beam exposure, a main deflect deflector 33 which is an electromagnetic deflector deflects a deflection field of 2 to 10 mm square, and a sub deflector 34 which is an electrostatic deflector 100 μm.
Deflect a subfield of about m □.

The pattern data is read from the memory 51 by the CPU 52, transferred to the data memory 54, and stored therein. Based on the pattern data read from the data memory 54, the pattern controller 55 decomposes the pattern for each shot. The pattern data decomposed into each shot is data for the main deflector 33, data for the sub deflector 34,
It is separated into data for the slit deflector 17 and signals such as a blanking signal SB to control the deflection of the electron beam.

Although not shown in order to avoid complicating the drawing, a detector for detecting the reflection particles from the stage 35 and the sample W is provided so as to face the sample W.

[0020]

However, in the conventional block exposure apparatus, the main deflector 33 is used.
Also, the transition of the sub deflector 34 takes time, and the speed of the exposure apparatus becomes a problem.

In the block exposure, the main deflector 33 and the sub deflector 34 perform vector scanning to draw a pattern. As described above, the main deflector 33 is an electromagnetic deflector and the sub deflector 34 is an electrostatic deflector. Main deflector 33
Has two sets of coils connected to, for example, a 4-stage series, and performs deflection on both the X and Y axes. The number of turns of these coils is several tens, and the inductance is about 50.
There is also μH, and the transition time from subfield to subfield is actually 50 μsec or longer. The number of subfields on one 8-inch wafer is 240 x 10,000, 2.4.
There are × 10 ⁶ jumps, and the main deflector 33 has a time of 120 μs for 50 μsec / jump.
It will depend on the settling of.

In order for the electron beam exposure apparatus to become a mass production technology for LSI, at least the exposure time per wafer needs to be 3 minutes and a throughput of 20 sheets / hour is required. If the jump time seems to take a long time as above,
It must be judged that it is hopeless that the electron beam exposure technology will become a wafer mass production technology. As a method for solving the above problems, the following has been conventionally performed. The first method independently controls three large, medium and small deflectors. More specifically, the large deflector positions the center of the subfield inside the main field, and the middle deflector positions the center of the subfield inside the subfield. The small deflector positions the beam inside the subfield. In this method, the coefficient control is complicated because it is necessary to determine the deflection efficiency gain, the rotation rotation, the trapezoidal distortion, and the Sdig focus value associated with the deflection position of each deflector for each deflector. Moreover, since the middle deflector is an electrostatic deflector, 50
In order to electrostatically deflect a region of about 0 μm, when a large current of about 5 μA is flown, charge-up occurs and the connection accuracy between fields deteriorates. Furthermore, since there are two electrostatic deflectors in the final lens, it is difficult to keep the focal length of the lens below a certain value. When the lens length is long, the chromatic aberration and the spherical aberration coefficient cannot be made small, and the beam blur becomes large at 0.2 μm or more when a large current is applied, and fine pattern pattern exposure cannot be performed. Furthermore, the medium deflector is 500μ
It is possible to deflect more than m. However, with this large deflection amount, the noise of 0.
Since it is large at 2 μm or more, the pattern resolution is not good when exposing a high-sensitivity resist.

In consideration of the above points, the present inventors previously described the main deflector 33 in the exposure apparatus shown in FIG.
Deflects the area of 2 mm □, and the sub deflector 34
When deflecting the area of 00 μm □, a method of feeding back the difference between the analog signal (DAC output signal) corresponding to the pattern in the drive unit 64 and the monitor signal of the amplifier unit to the sub deflector 34 has been proposed. Kaisho 62-27
7724 and U.S. Pat. No. 4,853,870.

FIG. 13 is a view showing the main part of the above-mentioned feedback method, and shows the internal structure of the drive parts 64 and 65 of FIG. The error detector 46 outputs the output signal of the D / A converter (DAC) of the drive unit 64 and the amplifier unit 44 of the drive unit 64.
And the difference signal indicating the difference is given to the amplifier section 45 of the drive section 65. The amplifier section 45 receives the difference signal and the D / A converter (DAC) 43 of the drive section 65.
The sub deflector 34 is controlled according to the output signal of the sub deflector 34. That is, as shown in FIG. 14A, the output signal of the D / A converter 42 rises quickly, but the amplifier unit 44
Since the load of the amplifier section 44 is the coil of the main deflector 33, the output signal of (5) rises slowly. The error detector 46 detects the difference (voltage difference) between these signals, and
A difference signal as shown in (A) is output. in this way,
The sub-deflector 34 compensates for the rising delay of the main deflector 33.

However, the above conventional feedback method has the following problems. As shown in FIG. 14B, when the output signal of the D / A converter 43 rises,
The distance between the centers of adjacent subfield regions (100 μm in the illustrated example), that is, 100 μm, must be deflected by the sub deflector 34. In order to make this deflection possible in the X and Y directions, the deflectable region of the sub deflector 34 must be at least 200 μm □. Such a sub-deflector 34 has a large scale and is inaccurate.
More specifically, for the pattern position coordinates X and Y inside the sub-field, the following coordinate conversion calculation considering the correction term of the sub-deflector 34 is performed, and the deflection control circuit 63 shown in FIG.
To calculate the actual exposure coordinates X'and Y '.

X ′ = gx · X + rx · Y + Hx · X · Y Y ′ = gy · X + ry · Y + Hy · X · Y where gx and gy are gain correction coefficients, rx and ry are rotation correction coefficients, and Hx and Hy are It is a trapezoidal correction coefficient. As shown in the above equation, the trapezoidal correction coefficient of the sub-deflector 34 exists, so that the positional accuracy of the pattern deteriorates when the settling feedback amount of the main deflector 33 is large.

In order to avoid this, since the correction calculation inside the sub-field needs to be performed by analog calculation, it takes time to deflect the sub-deflector 34 this time, for example, high-speed deflection of 50 nsec cannot be performed, and 100 n is required.
It takes more than sec. The throughput deteriorates from the above target value of 20 sheets / hour to 10 sheets / hour.

On the contrary, if the deflectable area of the sub-deflector 34 is used as it is at 100 μm, it is necessary to reduce the sub-field size to 50 μm □ or less, actually to about 30 μm □.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a charged particle beam exposure apparatus capable of jumping a beam between subfields with high pattern position accuracy and at high speed.

[0030]

FIG. 1A is a block diagram showing the principle of the present invention. FIG. 1A shows a cross section of the main deflector (electromagnetic deflector) 33. 33x is X
The main deflector coils 33x and 33y that generate a magnetic field that acts in the axial direction are the main deflector coils 33y that generate a magnetic field that acts in the Y-axis direction. These coils 33x and 33y are provided centering on the axis O of the exposure apparatus.

According to the present invention, the main deflector is provided with a correction deflector (correction electromagnetic deflector) 71 having correction coils 71x and 71y. A correction coil 71x is provided for the main deflector coil 33x, and a correction coil 71y is provided for the main deflector coil 33y. The number of turns of the correction coils 71x and 71y is set smaller than that of the main deflector coils 33x and 33y, so that the main deflector coils 33x and 33y are wound.
Correction coils 71x and 71y rather than the inductance of y
Reduce the inductance of. Normally, the main deflector coils 33x and 33y have 10 to 20 turns, while the correction coils 71x and 71y have, for example, 1 to 2 turns. As a result, the response speed of the correction electromagnetic deflector 71 to the control signal is determined by the main deflector 33.
Faster than.

[0032]

Since the main deflector coils 33x and 33y have large inductance, the responsiveness of the amplifier section connected to them is poor. That is, these coils 33
The magnetic fields generated by x and 33y cannot instantaneously respond to changes in the signal input to the amplifier unit (for example, the output signal of the D / A converter) (as shown in (A) of FIG. 1B, the amplifier unit). Monitor output does not follow the output signal of the D / A converter).

On the other hand, the correction coils 71x and 71y
Since the inductance of is small, the response of the amplifier unit connected to this is good. That is, these correction coils 7
The magnetic fields generated by 1x and 71y can instantly respond to changes in the input signal in the amplifier section. Therefore, (B) in FIG.
, The main deflector coils 33x and 3
It is possible to generate a magnetic field that compensates the response characteristic of 3y, and the combined magnetic field of the main deflectors 33x and 33y and the correction coils 71x and 71y changes the input signal of the amplifier section that loads the main deflector coils 33x and 33y. Can respond instantly to. Therefore, FIG. 1 (B)
As shown in (A) and (C), drawing can be performed even during the transition time when the magnetic field of the main deflector coil 33x rises. As a result, drawing can be performed at high speed.

The correction coils 71x and 71y provide response characteristics (rise characteristics) of the main deflector.
Therefore, it is not necessary to set a large deflection area of the electrostatic deflector that constitutes the sub-deflector, and the problems of the conventional technology can be solved.

Further, since the same coil as that of the main deflector is used for compensation, the beam deflection trajectory can be made the same.

[0036]

EXAMPLES In the examples described below, the correction coil 71
A configuration is provided in which the deflection width compensated by x and 71y is made as small as possible.

As shown in FIG. 14 described above, when the subfield is 100 μm □, the deflection width of ± 100 μm □, that is, the area of 200 μm □ in total is compensated (FIG. 1).
In the conventional example of No. 4, compensation is required by the sub deflector of the electrostatic deflector). The area of 200 μm square to be compensated is the same even when the correction coils 71x and 71y are used. Of course, the deflection area of the sub-deflector when the correction coils 71x and 71y are used is 100 μm □
Good.

On the other hand, it is preferable that the compensation area is as small as possible. This is because the pattern is blurred by the square of the amount of deviation from the normal deflection position. Therefore,
The amount of deflection of the correction coils 71x and 71y is suppressed as small as possible (for example, ± 50 μm □) to reduce blur,
It is preferable to obtain a compensation area of substantially 200 μm □.

In consideration of the above points, in the embodiment of the present invention, the deflection vector created by the main deflector coils 33x and 33y and the deflection vector created by the correction coils 71x and 71y are acted in the opposite directions to make the correction coil 71x. The area where 71 and 71y are deflected is ± 50 μm in the above example.

An electron beam type block exposure apparatus according to an embodiment of the present invention will be described below. The overall view of the exposure apparatus according to the present embodiment is the same as that of the exposure apparatus of FIG. 12 except that the correction deflector 71 including the correction coils 71x and 71y.
The main difference lies in the point where the above is provided and the point where the configuration of the drive section 64 is deflected accordingly. Therefore, in the present embodiment, the components used in the exposure apparatus shown in FIG. 12 are used as they are in the following description.

FIG. 2 is a diagram showing the operation principle of the embodiment in consideration of the above points. 2A, when the main deflector 33 deflects the electron beam to the position P1 as shown by an arrow V1, the D / A converter of the main deflector 33 (the D / A converter 42 of FIG. 2) shows the operation (t = 1 μsec) immediately after the output of (corresponding) changes to jump to the position of P2 as shown by the arrow V2, and FIG.
(B) shows that when the jumping operation is settled and the deflection position of the main deflector 33 changes to P2 (t = 60 μse).
The operation of c) is shown. In FIG. 2A, the output of the D / A converter indicates P2, but the deflection position of the main deflector 33 remains P1. At this time, if the deflection vector indicated by the arrow V3 is generated by the correction deflector 71, the combined vector of the vectors V2 and V3 indicates the center O. That is, it means that the correction amount shown by the arrow V4 is added to the deflection amount shown by the arrow V2. For example, the Sufffield is 100μ
In the case of m □, the vector V3 has a size of 50 μm and is in a direction from the position P1 toward the center O (this direction is defined as a plus direction).

After that, as time passes, the deflection position of the main deflector 33 passes through the center O and reaches the position P2. In the meantime, the deflection position of the correction deflector 71, that is, the vector V3 is changed to change the main deflector 3
The composite vector with 3 always points to the center O. Therefore, the vector V3 decreases from +50 μm, then once becomes zero and then increases in the negative direction, and when the main deflector 33 is settled as shown in FIG.
It becomes 50 μm. As a result, the composite vector is always the center O
The deflected electron beam jumps to the center O immediately after the output of the D / A converter has settled. The point where the deflection vector V3 by the correction deflector 71 becomes zero corresponds to the position of the broken line shown in (b) of FIG.

FIG. 3 is a diagram showing a practical operation to which the principle shown in FIG. 2 is applied. In FIG. 3, a region indicated by a solid line indicates a subfield. (1) and (2) mean the centers of the corresponding subfields. The thick solid line arrow means the deflection vector created by the main deflector 33 having the main deflector coils 33x and 33y (also referred to as vector data given thereto), and the thin solid line arrow shows the correction deflector 71 having the correction coils 71x and 71y. It means a deflection vector to be created (vector data given to this).

A case where the main deflector 33 causes the electron beam to jump from the center (1) of the subfield to the center (2) of the adjacent subfield will be described. Center (1)
At the end of the exposure of the subfield having D, D / which outputs the deflection data to the main deflector via the amplifier unit
The output signal of the A converter (corresponding to the D / A converter 42 in FIG. 13), the deflection position of the main deflector 33, the deflection position of the correction deflector 71, and the total deflection position of the main deflector 33 and the correction deflector 71 are respectively: The output is as follows (see FIG. 3A): Amplifier unit output: Deflection position of main deflector 33: Vector m (after settling) Deflection position of correction deflector 71: Vector a + Vector S (S = 0) Total beam Deflection position: (1) where the correction deflector 71 is the offset vector a
And the main deflector settling feedback vector S. At the end of the exposure of the subfield with center (1), the vector S is zero. That is,
The correction deflector 71 outputs a magnetic field that produces a deflection of vector a. The offset vector a is not centered on the deflection position of the main deflector 33 (1), but
It is an offset due to the upper right corner. Further, the main deflector settling feedback vector S is a vector that acts together with the offset vector a at the time of jump, and the total beam deflection position of the main deflector 33 and the correction deflector 71 is always at the center of the subfield ((2 ))
It is to be in.

Next, the respective parts at the start of the jump operation to the center (2) subfield are as follows (FIG. 3).
(See (A)).

Amplifier unit output: Deflection position of main deflector 33: (not yet moving) Deflection position of correction deflector 71: Vector A + vector S = B Total beam deflection position: (2) Immediately after the start of the jump operation (however, Main deflector 3
3), the output of the amplifier section of the main deflector 33 indicates. However, at this time, due to the characteristics of the main deflector 33, the deflection vector of the main deflector 33 remains pointing at. Also, the feedback vector S
Is set so that the combined vector with the offset vector A is set to the vector B. The feedback vector S has a starting point of and an ending point of. As a result, the combined vector B indicates the center (2) of the subfield. Therefore, the combined vector of the vector m, the vector S, and the vector A indicates the center (2) of the subfield.

The respective parts when the main deflector 33 is settled are as follows (see FIG. 3B).

Amplifier section output: Deflection position of main deflector 33: Vector M (after statically settled) Deflection position of correction deflector 71: Vector A + Vector B (B = 0) Total beam deflection position: (2) As described above, The deflection position of the main deflector 33 is at the position indicated by the output of the amplifier section, and the deflection position of the correction deflector 71 is only the offset vector A (the offset vector A acts on the center (2), and the center ( The same as the offset vector acting on 1)). During the transition from (A) to (B) of FIG. 3, since the main deflector settling feedback vector S changes as described with reference to FIG. 2, immediately after the D / A converter of the main deflector 33 has settled. It is possible to position the electron beam at the center (2).

In the above operation, the correction deflector 71
It is sufficient that the coils 71x and 71y are capable of deflecting within a range of ± 50 μm.

FIG. 4 shows a plurality of subfields on the wafer. The number in parentheses indicates the center of the subfield, and exposure is performed in the order of increasing number. Also, the numbers in the circles indicate the deflection positions of the main deflector 33. In the example of FIG. 4, while scanning in the X direction, scanning is performed sequentially from the bottom in the + Y direction. The centers (1) to (5) operate as shown in FIGS. 3A and 3B, and the centers (6) to (10) operate so as to return to the X direction. The deflection position of the main deflector 33 is the upper left corner of the center (6) to (10) subfield, and the deflection position of the correction deflector is the deflection vector in the direction opposite to the deflection vector of the main deflector 33. Therefore, at the time of jump, if the change of the feedback vector S is determined in advance by using the corresponding vector amount, the above-described operation can be performed.

The traveling directions of the electron beam in the scanning of the electron beam are a combination of the X direction and the Y direction, and are not limited to the above two ways, but there are two more ways and there are a total of four ways.
For each of these four combinations, the deflection vector M of the main deflector 33 and the correction deflector 7
Since the deflection vector A (offset vector A) of 1 can be uniquely determined, if the X advancing direction (plus or minus direction) and the Y advancing direction (plus or minus direction) at the time of scanning are known, These vector quantities can be easily set.

FIGS. 5A and 5B are diagrams showing four types of scanning. In FIG. 5, ◯ is a symbol indicating the starting point of each scan. The X and Y coordinates are defined with the center of each subfield (illustrated as a block) as the origin. In FIG. 5A, the scan I is in the + Y direction in the scanning direction (the traveling direction of the electron beam), and the X coordinate of the starting point ◯ is negative, and in the scan II, the scanning direction is in the + Y direction and the X coordinate of the starting point ◯ is positive. is there. In FIG. 5B, scan II
For I, the scanning direction is the −Y direction and the X coordinate next to the starting point ◯ is negative, and for scanning IV, the scanning direction is the −Y direction, and the X coordinate next to the starting point ◯ is positive.

Corresponding to each of the above scans I, II, III and IV, the main deflector addition value (deflection vector M) to be added to the center coordinates of the sub field and the center coordinates of the sub field are added. FIG. 6 shows the coordinates of the correction deflector addition value (offset vector A) to be obtained. For example, in Case I, the main deflector addition value is a vector from the center to the coordinates (50, 50), and the correction deflector addition value is the center to the coordinates (−5).
0, -50). Although a bar is used in FIG. 6 because it is a vector, "/" is used in the specification in place of the bar meaning a vector.
Therefore, the above two vectors are converted into / (50, 50) and /
It is expressed as (-50, -50).

As shown in FIG. 7, the vector data shown in FIG. 6 can be easily set by reading the vector data stored in the memory using the line feed in the Y direction and the X coordinate value as the memory address. For example, in case I, the line feed in the Y direction is in the + Y direction, and the X coordinate value is negative. Memory outputs M1x, M1y, A1x, A in this case
1y is 50, 50, -50, and -50, respectively.

FIG. 8 shows a means for implementing the method using the tables shown in FIGS. 6 and 7. Registers 73 and 74 store the Y coordinate value (Y old data) of the point in the jump source subfield and the Y coordinate value (Y new data) of the point in the jump destination subfield, respectively. The X coordinate value (X old data) of the point in the subfield of the jump source in registers 75 and 76, respectively
And the X coordinate value (X new data) of the point in the jump destination subfield. The calculator 77 reads the Y coordinate values from the registers 73 and 74, calculates the difference δY, and outputs the difference δY to the code determination circuit 79. Similarly, the calculator 78 reads the X coordinate values from the registers 75 and 76, calculates the difference δX, and outputs the difference δX to the code determination circuit 79. The code determination circuit 79 determines the code of the line feed in the Y direction from the difference δY and the code of the X coordinate value from δX. Then, the code determination circuit 79 outputs an address signal corresponding to the determined code to the memory 80. The memory 80 is divided into four areas Mx, My, Ax, and Ay, and M1x to M4x, M1y in FIG.
.About.M4y, A1x to A4x and A1y to A4y are stored. Coordinate data corresponding to the address signal is read from the memory 80. For example, in case I,
From the regions Mx, My, Ax and Ay, M1x (=
50), M1y (= 50), A1x (= -50) and A
1y (= -50) is read.

In practice, the main deflector 33 is provided with a product obtained by multiplying the added values Mx and My obtained as described above by the correction coefficient for the stage 35 of the main deflector. For example, in case I, the deflection vectors indicating the deflection position coordinates Mx and My of the main deflector are as follows.

[0057]

[Equation 1]

Here, Gsx and Gsy are gain correction coefficients, and Rsx and Rsy are rotation correction coefficients.

Similarly, the correction coefficient of the correction deflector 71 with respect to the stage 35 is added value A obtained as described above.
The product obtained by multiplying x and Ay is given to the correction deflector 71. For example, in case I, the deflection vector indicating the deflection position coordinates Ax and Ay of the correction deflector 71 is as follows.

[0060]

[Equation 2]

Here, gsx and gsy are gain correction coefficients, and gsx and gsy are rotation correction coefficients.

FIG. 9 is a block diagram showing a main part of a block exposure type electron beam exposure apparatus according to the above embodiment of the present invention. The portion shown in FIG. 9 corresponds to the drive unit 64 shown in FIG.
Used in place of. The same components as those described above are designated by the same reference numerals.

The deflection control circuit 63 controls the overall operation of the main deflector 33 having the main deflector coils 33x and 33y shown in FIG. 9, the correction deflector 71 having the correction coils 71x and 71y, and the sub deflector 34 shown in FIG. The control of the sub-deflector 34 is the same as in the conventional case, and will be omitted in the following description. The deflection control circuit 63 writes the X coordinate value and the Y coordinate value of the main deflection position (center of the subfield) in the registers 81 and 82. Similarly, the deflection control circuit 63
Outputs the X coordinate value and the Y coordinate value to the offset determining circuit 92. The X and Y coordinate values are, for example, 20-bit parallel data.

The X and Y coordinate values of the main deflection position written in the registers 81 and 82 are corrected by the cell / stage area correction circuit 83 in consideration of the correction data concerning the distortion of the center of the subfield. , 20-bit serial data, for example. Then, the correction circuit 83
Is an adder 84 for the X and Y coordinate values converted into serial data.
And 85 respectively. The correction data in the subfield center relates to stig, focus, gain of the sub deflector 34, and trapezoid. The outputs of the main deflector 33 and the correction deflector 71 change during the drawing of the subfield, but the position of the center of the subfield, which is the vector of the sum of the two, does not change during the exposure of the subfield, so the above correction data is taken into consideration.

The offset determination circuit 92 has the circuit configuration shown in FIG. 8, and the X and Y received from the deflection control circuit 63.
Main deflector addition values Mx, My using coordinate values
(Offset value) and correction deflector addition value (offset value) Ax and Ay are output. The main deflector addition values Mx and My are written in the registers 93 and 94, respectively, and the correction deflector addition values Ax and Ay are written in the registers 95 and 96, respectively. The offset value output from the offset determination circuit 92 is corrected by the correction coefficient of the above-described Expression 1 and Expression 2.

The adder 84 adds the offset value Mx read from the register 93 to the corrected X coordinate value,
The added X coordinate value is output to the D / A converter (DACX) 86. Similarly, the adder 85 adds the offset value My read from the register 94 to the corrected Y coordinate value, and adds the added Y coordinate value to the D / A converter (DACY).
Output to 87. The X coordinate value of the analog signal converted by the D / A converter 86 is added to the X direction calibration value by the analog addition value 88. The X-direction calibration value is output by the CPU 52 shown in FIG. 12 via the calibration D / A converter (CAL-DACX) 106. The X direction calibration value is shown in FIG.
It is used to adjust the relationship between the vectors M and A shown in (B). That is, in the static state shown in FIG. 3B, the vectors M and A have the same magnitude and act in opposite directions. However, actually, the directions of the vectors M and A may be slightly deviated, and a difference vector may occur. The X-direction calibration value cancels the X-direction component of this difference vector.

Similarly, the Y coordinate value of the analog signal converted by the D / A converter 87 is added to the Y direction calibration value by the analog addition value 90. The Y-direction calibration value is output by the CPU 52 shown in FIG. 12 via the calibration D / A converter (CAL-DACY) 107. The Y-direction calibration value cancels the Y-direction component of the difference vector.

The output signal (current) of the analog adder 88 flows through the main deflector coil 33x, and the output signal (current) of the analog adder 89 flows through the main deflector coil 33y. The resistor R1 connected in series to the coil 33x outputs a monitor signal (voltage) and outputs it to the difference circuit 89. Similarly, the resistor R2 connected in series to the coil 33y outputs a monitor signal (voltage) and outputs it to the difference circuit 91. The difference circuit 89 takes the difference between the output signal of the D / A converter 86 and the monitor signal from the resistor R1 and outputs the difference signal to the summing amplifier 101. This difference signal corresponds to the difference between the solid line and the dotted line in (a) of FIG. 1 (B) in the X direction, and also corresponds to the X component of the vector S of FIG. 3 (A).
Similarly, the difference circuit 91 calculates the difference between the output signal of the D / A converter 87 and the monitor signal from the resistor R2, and outputs the difference signal to the addition amplifier 102. This difference signal corresponds to the difference between the solid line and the dotted line in (S) of FIG. 1B regarding the Y direction, and also corresponds to the Y component of the vector S in FIG. 3A.

The offset value Ax written in the register 95 and the offset value Ay written in the register 96
D / A converter (DACAX) is read individually.
97 and a D / A converter (DACAY) 98 convert into an analog signal and output to the addition amplifiers 101 and 102. The addition amplifier 101 adds the difference signal in the X direction from the difference circuit 89, the offset value in the X direction from the D / A converter 97, and the correction value in the X direction in consideration of various corrections from the memory 99, Output to the analog correction circuit 103. The correction values in the X direction are for stage feedback (STG FBX), speed correction for scanning delay caused by stage movement, and eddy current compensation. Similarly, the summing amplifier 10
2 is a difference signal in the X direction from the difference circuit 91,
The offset value in the Y direction from the D / A converter 98 and the correction value in the X direction from the memory 100 in consideration of various corrections are added and output to the analog correction circuit 103. Similar to the X direction, the correction value in the Y direction is for stage feedback (STG FBX), speed correction for the scanning delay caused by the movement of the stage, and eddy current compensation.

The analog correction circuit 103 includes the addition amplifier 1
Gain gx in the X direction for output signals 01 and 102
And the rotation ry, the gain gy in the Y direction and the rotation ry are calculated as correction coefficients, and the amplifier 104
The correction coils 71x and 71y are driven via 105 and 105.

The comparator 106 is the amplifier 104.
And 105 to output the difference signal to the sequence controller 60 (FIG. 12). The difference signal is
Used to determine the start time of exposure. As shown in FIG. 1B, it is preferable to start the actual drawing when the output signals of the D / A converters 86 and 87 have risen completely. This time point is detected by the difference signal, and the sequence controller 60 is notified.

FIG. 10 is a view showing the installation state of the correction deflector 71. There are a plurality of main deflector coils 33x for deflecting the electron beam in the X direction (3 in the example of FIG. 10).
3) coils are connected in series to surround the optical axis O. Similarly, the main deflector coil 33y that deflects the electron beam in the Y direction is provided so as to connect a plurality of (three in the example of FIG. 10) coils in series and surround the optical axis O. On the other hand, the correction coil 71x in the X direction is one coil having 1 to several turns. Similarly, the correction coil 71y in the Y direction is one coil having 1 to several turns. The correction coils 71x and 71y are provided in the space surrounded by the main deflector coils 33x and 33y,
It is provided near these. The vertical positions of the correction coils 71x and 71y are considered so that the deflection trajectory of the correction coils 71x and 71y is the same as the deflection trajectory of the main deflector 33.
In FIG. 10, reference numeral 111 denotes a housing that houses a water cooling pipe (not shown) for cooling the coil, and 112.
Is a ferrite pole piece, 113 is a magnetic yoke, 11
Reference numeral 4 is a lens winding, and 115 is a pipe for sending air to cool the coil.

FIG. 11 is a diagram showing another configuration example of the correction deflector 71. In the example of FIG. 10, the correction coil 71x
And 71y each have a plurality of coils connected in series. In the example of FIG. 11, the correction coils 71x and 7x
Each coil of 1y has, for example, one turn, and one coil is provided for each of the main deflector coils 71x and 71y.
It corresponds to one-to-one. Further, the correction coil 7 shown in FIG.
In each of 1x and 71y, one of the three coils connected in series, for example, the top coil may be omitted.

The embodiment of the present invention has been described above. The present invention is not limited to the above embodiment, but can be applied to other exposure apparatuses.

[0075]

As described above, according to the present invention,
The following effects can be obtained.

According to the first aspect of the invention, since the correction electromagnetic deflector for correcting the deflection trajectory of the electromagnetic deflector and the control means for controlling the correction electromagnetic deflector are provided, the electrostatic deflector is not used. By correcting the delay of the rising characteristic of the electromagnetic deflector, the beam can be quickly jumped to a desired position.

According to the second aspect of the invention, the correction electromagnetic deflector has a coil, and the inductance of the coil is smaller than the inductance of the coil of the electromagnetic deflector. Therefore, the correction electromagnetic deflector has good responsiveness. .

According to the third aspect of the present invention, in the control means, the composite vector of the deflection vector determined by the electromagnetic deflector and the deflection vector determined by the correction electromagnetic deflector becomes the center of the area to be drawn. Since the means for controlling the correction electromagnetic deflector is provided as described above, the beam position by the main deflection can always be set at the center of the area to be drawn.

According to the fourth aspect of the invention, since the correction electromagnetic deflector has a characteristic of correcting the rising characteristic of the electromagnetic deflector, the delay of the rising of the response characteristic of the electromagnetic deflector is corrected. , The beam can be quickly jumped to a desired position.

According to the fifth aspect of the present invention, the control means outputs the first offset signal to the electromagnetic deflector to move the charged particle beam to a predetermined position deviated from the center of the area to be exposed by the electromagnetic deflector. Offset control for irradiating the charged particle beam to the center of the region to be exposed by outputting a second offset signal to the correction electromagnetic deflector. Since the means is provided, the deflection area of the correction electromagnetic deflector can be suppressed small, and the blurring of the pattern can be reduced.

According to the sixth aspect of the invention, the control means monitors the signal for driving the electromagnetic deflector and the signal flowing through the electromagnetic deflector, and controls the correction electromagnetic deflector according to the difference between them. The correction electromagnetic deflector can be controlled according to the characteristics of the electromagnetic deflector.

According to the seventh aspect of the invention, the control means monitors the signal for driving the electromagnetic deflector and the signal flowing through the electromagnetic deflector, and adds the difference between them to the second offset signal. Since the means is provided, it is possible to correct the rising characteristic of the electromagnetic deflector while keeping the deflection area of the correction electromagnetic deflector small.

According to the eighth aspect of the present invention, the offset determining means sets a plurality of combinations of the first and second offset signals depending on the scanning direction of the charged particle beam and the position information of the area to be exposed. With the memory means for storing, the first and second offset signals can be easily determined.

According to the ninth aspect of the present invention, the correction electromagnetic deflector has first and second coils for deflecting charged particles in two orthogonal directions. Since the inductance is smaller than that of the electromagnetic deflector, the beam can be quickly deflected in the X and Y directions to correct the rising characteristic of the electromagnetic deflector. According to the tenth aspect of the invention, each of the first and second coils has a single coil, so that the configuration is simple.

According to the eleventh aspect of the present invention, each of the first and second coils has a plurality of coils connected in series, so that the adjustment becomes easy.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention.

FIG. 2 is a diagram for explaining the operation principle of the embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of the embodiment of the present invention.

FIG. 4 is a diagram showing deflection control when scanning a wafer according to an embodiment of the present invention.

FIG. 5 is a diagram for explaining a scanning direction related to an offset value.

FIG. 6 is a diagram showing an example of an offset value.

FIG. 7 is a diagram showing parameters serving as an address signal when an offset value is stored in a memory.

FIG. 8 is a diagram showing a circuit configuration for outputting an offset value.

FIG. 9 is a block diagram showing a main part of an embodiment of the present invention.

FIG. 10 is a diagram showing a configuration example of a main deflector, a sub deflector, and a correction deflector.

FIG. 11 is a diagram showing another configuration example of a main deflector, a sub deflector, and a correction deflector.

FIG. 12 is a diagram showing a configuration example of a conventional block exposure type electron beam exposure apparatus.

FIG. 13 is a block diagram showing a conventional correction method.

FIG. 14 is a diagram showing a problem of the conventional method shown in FIG.

[Explanation of symbols]

 33 main deflector 33x, 33y main deflector coil 71 correction deflector 71x, 71y correction deflector coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takamasa Sato 1015 Kamiodanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Hisaya Nishino 1015, Kamedotachu, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited ( 72) Inventor Juichi Sakamoto 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Hidefumi Yahara, 1015, Kamedotachu, Nakahara-ku, Kawasaki, Kanagawa Prefecture Fujitsu Limited (72) Inventor, Seto Isamu Kanagawa 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Fukuoka Prefecture Fujitsu Limited (72) Inventor Masami Takigawa 1015 Kamiotanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Kanagawa Prefecture (72) Akio Yamada 1015 Ueda-anaka, Nakahara-ku, Kawasaki-shi, Kanagawa Address within Fujitsu Limited

Claims (11)

[Claims] 1. An electromagnetic deflector (33) and an electrostatic deflector (3)
In the charged particle beam exposure apparatus for deflecting the charged particle beam in 4) to draw a pattern, the deflection orbit of the electromagnetic deflector is corrected, and the correction electromagnetic deflector (7) has a faster response speed to the control signal than the electromagnetic deflector.
1) and control means (89-105) for controlling the correction electromagnetic deflector
And a charged particle beam exposure apparatus. 2. The charging according to claim 1, wherein the correction electromagnetic deflector (71) has a coil (71x, 71y), and the inductance of the coil is smaller than the inductance of the coil of the electromagnetic deflector. Particle beam exposure system. 3. The control means (89-105) is arranged so that the composite vector of the deflection vector determined by the electromagnetic deflector and the deflection vector determined by the correction electromagnetic deflector is at the center of the area to be drawn. Charged particle beam exposure device according to claim 1, characterized in that it comprises means (92) for controlling the correction electromagnetic deflector (71). 4. The charged particle beam exposure apparatus according to claim 1, wherein the correction electromagnetic deflector (71) has a characteristic of correcting a rising characteristic of the electromagnetic deflector. 5. The control means outputs a first offset signal to the electromagnetic deflector to control the electromagnetic deflector to irradiate the charged particle beam at a predetermined position deviated from the center of the region to be exposed, A second offset signal is output to the correction electromagnetic deflector (71) to output the correction electromagnetic deflector (71).
2. The charged particle beam exposure apparatus according to claim 1, further comprising offset determining means (92) for controlling so that the charged particle beam is irradiated to the center of the area to be exposed. 6. The control means monitors the signal for driving the electromagnetic deflector and the signal flowing through the electromagnetic deflector, and controls the correction electromagnetic deflector according to the difference between them (89,
91, 101, 102), The charged particle beam exposure apparatus according to claim 1, further comprising: 7. The means for monitoring the signal for driving the electromagnetic deflector and the signal flowing through the electromagnetic deflector, and adding the difference between the signals to the second offset signal.
91, 101, 102), The charged particle beam exposure apparatus according to claim 1, further comprising: 8. The offset determining means (92) stores a plurality of combinations of first and second offset signals according to a scanning direction of a charged particle beam and position information of an area to be exposed (memory means ( 80) The charged particle beam exposure apparatus according to claim 5, further comprising: 9. The correction electromagnetic deflector comprises first and second coils (71) for deflecting charged particles in two directions orthogonal to each other.
x, 71y), wherein the inductances of the first and second coils are smaller than the inductance of the electromagnetic deflector.
Charged particle beam exposure apparatus as described. 10. Each of the first and second coils comprises:
10. The charged particle beam exposure apparatus according to claim 9, which has a single coil. 11. Each of the first and second coils comprises:
10. The charged particle beam exposure apparatus according to claim 9, further comprising a plurality of coils connected in series.