JPH0282513A - Charged particle beam lithography - Google Patents

Abstract

PURPOSE:To shorten scaling time by changing according to a scaling rate the amount of a movement of a stage by pattern data to move the stage. CONSTITUTION:A photoelectric detection mechanism 9 includes therein a half mirror which diverts a laser light from a laser oscillator 8 into two different optical paths, the light diverted along the one optical path entering a reflecting mirror 7 mounted on the side surface of a stage 4 and the other diverted light impinging a reference reflecting mirror disposed therein. In an adjustment performed before pattern drawing where beam deflection width is matched with a length reference defined by a laser length measuring system, the length reference defined by the laser length measuring system is changed in itself according to a scaling rate. For example, in a case where the entire pattern to be drawn is scaled down by K%, correction of scaling-down by K% is added to the stage movement. That is, a control device 10 issues to a stage movement driving mechanism 6 instructions to move the stage 4 by an amount S(100-K)/100, i.e., the amount S of the stage movement reduced by K%. Herein, the amount of beam deflection is also adjusted according to said instructions.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a charged particle beam that changes the size of the entire pattern by changing the length reference of the length measurement system (laser lJl length system) of the stage. Concerning drawing methods.

[Prior Art] Recently, charged particle beam lithography apparatuses such as electron beam lithography apparatuses and ion beam lithography apparatuses have been attracting attention as a means for manufacturing LSI devices, VLSI devices, and VLSI devices.

For example, in the case of an electron beam lithography system, an electron beam from an electron beam generating means is focused on a material on which a pattern is to be drawn, and at the same time is deflected based on data on the size and drawing position of each pattern to be drawn. The system scans the material with the electron beam to draw each predetermined pattern on the material.

Now, for example, some optical devices transmit light of various wavelengths and separate the light of various wavelengths by applying the wave light to grating patterns with various pitches on the receiving side. In order to vary the resolution, it is sometimes desirable to change the overall size of such a grating pattern. In this way, if you want to slightly enlarge or reduce the size of all patterns to be drawn, convert the pattern data from the pattern data source that stores the pattern source data (design data) into drawing data that can be drawn by the drawing device. At this time, the entire pattern data is scaled to enlarge or reduce the size of the entire pattern data, or the entire pattern data stored in the pattern data generation source is redesigned.

[Problem to be solved by the invention] However, with the former method of scaling pattern data, it is not possible to change the data smaller than the data increment (minimum unit) of the data format, and the data is rounded to the data increment. It gets lost.

For example, if the pitch between the grating patterns is loonm, and the data increment of the data format is 5 nm, and you want to scale the pitch to 1101n, even if you apply scaling like the former, it will not be rounded to the increment. It becomes 1100n,
1101n. That is, in the former method, there is a limit to the reduction of pattern data due to the data increment. Furthermore, in such a method, every time the amount of scaling is changed, it is necessary to reconvert the source data from the pattern data generation source into drawing data. Therefore, it took a lot of time.

Moreover, the latter method took a lot of time.

The present invention aims to solve such problems.

Now, normally, in the electron beam writing method, standards such as pattern length and direction are determined by a stage length measurement system (usually a laser length measurement system is used, henceforth referred to as laser length measurement system). ing. Typically, the total pattern to be written is larger than the deflection range (deflection field) of the beam. In other words, the entire pattern to be drawn spans multiple fields, but when drawing such a pattern, a stage is used to move between each field, and by scanning each field with a beam, multiple fields can be drawn. Such a pattern is drawn by connecting deflection fields, but the plurality of fields must be connected smoothly.

For this reason, before pattern writing, adjustments are made to match the amount and direction of beam deflection for the amount and direction of movement of the stage, so that the reference of the laser length measurement system and the beam deflection reference are matched. . Adjustment to match the amount of beam deflection to the amount of movement of the stage is performed, for example, by detecting marks formed on the material. That is, first, a beam scans the material, and a backscattered electron detector (or secondary electron detector) placed above the material detects the backscattered electrons (or secondary electrons) generated from the material. The mark is detected by Next, move the stage by a predetermined amount A5 in a certain direction (for example, the X direction).
move it. Next, the X-direction scanning signal applied to the deflection system is gradually changed to gradually scan the material with the beam in the X-direction. The amount of deflection until the mark is detected by this scanning is B
, when the gain of the deflection system amplifier is 61, the gain of the deflection system amplifier is set to 02 (-CIA/B) so that the mark is detected when the deflection amount is A. Change this adjustment to Y
Also do this for direction. To adjust the deflection direction of the beam to match the direction of movement of the stage, first, the beam scans the material and marks are detected. Next, the stage is moved by a predetermined amount in the C1X direction. Next, an X-direction scanning signal with a deflection amount of C is applied to the X-direction deflection system, and the beam is deflected flc to scan the material in the X-direction.

Next, the Y-direction scanning signal applied to the Y-direction deflection system is gradually changed to gradually scan the material with the beam in the Y-direction. If a mark is detected when the deflection amount is Δ in the scanning,
The rotation angle θ in the same direction of the beam in the X direction with respect to the X direction movement direction of the stage is determined by Δ/A − tanθ, and after that, when the deflection signal P is input to the X direction deflection system,
Ptanθ is input to the Y-direction deflection system. Y
The same applies to the rotation angle of the direction.

Furthermore, when the stage is moved between each field during pattern writing, the stage position is measured by a laser length measurement system, and the error between the measured value and a predetermined setting value is fed back to the beam deflection system to move the stage. The stop position error is corrected.

[Means for Solving the Problems] Therefore, the present invention changes the amount of movement of the stage according to pattern data by a scaling rate, moves the stage based on the changed amount of movement, and also changes the amount of movement of the stage based on the pattern data to the deflector of the charged particle beam. The gain of the amplifier for the deflection signal to be applied was changed according to the scaling factor.

[Embodiment] FIG. 1 is a schematic diagram of an electron beam lithography apparatus shown as an embodiment of the charged particle beam lithography method of the present invention.

In the figure, 1 is an electron gun, 2 is a focusing lens, 3 is a deflector (actually, one in the X direction and one in the Y direction are arranged), 4
is a stage, 5 is a material, 6 is a stage movement drive mechanism, 7
is a reflecting mirror, 8 is a laser oscillator, 9 is a photoelectric detection mechanism, 10
is a control device, 11 is a deflection signal generation circuit, 12 is an amplifier,
13 is a DA converter. A backscattered electron detector (not shown) is placed directly above the material 5 for use in mark detection, etc., and the signal detected by this detector is amplified by an amplifier (not shown). and sent to the control device 12. In charged particle beam writing, mark position detection is extremely common and will not be explained in detail here, but in the control device 12, the mark position is determined based on a mark signal from the detector (not shown). or,
The photoelectric detection mechanism 9 has a semi-transparent mirror arranged inside, and the semi-transparent mirror divides the laser light from the laser oscillator 8 into two different optical paths, one of which is connected to a reflecting mirror 7 attached to the side of the stage 4. and the other side to a reference reflector placed inside. Therefore, interference fringes appear on the surface of the semi-transparent mirror due to the re-reflected light reflected by both reflecting mirrors. At this time, each time the stage 4 moves a distance of half a wavelength, a pulse signal corresponding to the brightness and darkness of the interference fringes is generated, and the stage 4 operates to generate the number of pulses.

Now, in adjusting the beam deflection width (amount) to match the length standard determined by the laser length measurement system, which is performed before pattern writing, the length standard determined by the laser length measurement system itself is adjusted according to the scaling rate. I can change it.

For example, if all patterns to be drawn are to be reduced by, for example, K%, a correction for the % reduction is added to the stage movement.

That is, the control device 10 sends a command to the stage movement drive mechanism 6 to move the stage 4 by an amount 5 (100-K)/100, which is a reduction of K% from the original stage movement amount S. The amount of beam deflection is also adjusted accordingly. This alignment adjustment is performed in the same manner as the mark detection described above. First, a beam is scanned over the material to detect marks.

Next, the stage is reduced by K% of the predetermined amount S (
100-K)/100, and the stage is moved, for example, in the X direction by the stage movement drive mechanism 6. Next, the deflection signal generating circuit 13, which operates according to a command from the control device 10, sends a signal to the deflector 3.
By gradually changing the X-direction scanning signal given to the object (in the X-direction), the beam gradually scans the material in the X-direction. If the gain of the amplifier of the deflection system is Gm, the deflection amount until the mark is detected by the scanning is T1, and the gain of the deflection system amplifier 14 (in the The gain is controlled by the command from the control device 10.
(= G m S / T). Note that this adjustment is also performed in the Y direction.

In this way, the length reference of the laser length measurement system is changed by %, and a pattern is drawn with the reference of the beam deflection width adjusted to the length reference of the laser length measurement system changed by the corresponding %.

During actual pattern drawing, the electron beam from the electron gun 1 is focused onto the material 5 by the focusing lens 2, and at the same time, it is deflected based on each pattern data from the deflection signal generation circuit 13 that receives commands from the control device 10. The system scans the material with the electron beam to draw each predetermined pattern on the material.

During this pattern drawing, when drawing a pattern from one deflection field to the next, the stage movement drive mechanism 6 moves the stage 4 by a command from the control device 10 to reduce the original inter-field movement amount F by % F. (10
0-K)/100. When the stage is moved between each field, the stage position is measured by the photoelectric detection mechanism 9, and the error between the measured value and the set value is fed back to the deflection signal generation circuit 11.
Stage stop error is corrected.

In this way, the stage 4 moves by an amount reduced by %, and the deflector 12 also adjusts the beam deflection width reference to the length reference of the laser length measurement system, which has been changed by the corresponding percentage. Since drawing is performed, all patterns drawn on the material 5 are drawn reduced in size by % compared to the original size. Figure 2 shows how each field is drawn.
3 + 04 + . . . represents the center of each field, and 01 to o2. o2 to 03 + 03
to 04+ . . . indicate the amount of movement between each field of the stage.

In the embodiment described above, when the stage is moved, the amount of movement is corrected according to the scaling rate, and at the same time, the amount of deflection of the beam is adjusted to this. However, other embodiments include the following method.

As shown in the diagram of the laser length measurement system viewed from the optical axis direction in Figure 3, when the position of the laser oscillator 8 is moved by an angle θ rotation according to the scaling rate, and the angle of incidence on the reflecting mirror 7 is θ. ,
The wavelength λO of the laser beam in the length measurement direction (direction perpendicular to the reflecting mirror 7) may be set to λO·COSθ. In this way, the wavelength of the laser beam in the length measurement direction is varied according to the slaling rate, and under the changed laser light, the beam deflection width (amount) is matched to the length standard determined by the laser length measurement system. Make adjustments to In this way, when drawing a pattern, scaling of the pattern corresponding to (λoacosθ−λ0)/λO is performed.

Note that the gain of the deflection system amplifier may be simply changed according to the scaling rate.

Further, each of the above embodiments can also be applied to an ion beam lithography apparatus.

[Effects of the Invention] When it is desired to slightly enlarge or reduce the size of all patterns to be drawn, the present invention can scale all pattern data itself or scale all patterns stored in the pattern data source, as in the conventional case. Rather than redesigning the pattern data, the length standard determined by the laser length measurement system is used to adjust the beam deflection width (amount) to match the length standard determined by the laser length measurement system, which is performed before pattern drawing. Since this is changed in accordance with the scaling rate, the data can be reduced to a smaller size than the data increment (minimum unit) without being limited by the data increment (minimum unit) of the data format.

Additionally, there is no need to reconvert the source data from the pattern data generation source to drawing data every time the scaling amount is changed as in the past, and the length standard itself determined by the laser length measurement system can be easily changed. , it only needs to be changed according to the scaling rate, so scaling does not take much time. 4,

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an electron beam lithography apparatus shown as an embodiment of the charged particle beam lithography method of the present invention, FIG. 2 is a diagram used to explain its operation, and FIG. 3 is a diagram showing another embodiment of the present invention. FIG. 2 is a partial view of FIG. 1 used to explain an example. 1: Electron gun 2: Focusing lens 3: Deflector 4:
Stage 5; Material 6; Stage movement drive mechanism 7 Two reflecting mirrors 8: Laser oscillator 9: Photoelectric detection mechanism 10: Control device 11: Deflection signal generation circuit 1
2: ANBU 13: DA converter patent applicant JEOL Ltd.

Claims (1)

[Claims] 1. The amount of movement of the stage according to the pattern data is changed by a scaling rate, the stage is moved based on the changed amount of movement, and the amplifier of the deflection signal applied to the charged particle beam deflector is changed. A charged particle beam drawing method characterized in that the gain is changed according to the scaling rate. 2. When adjusting the beam deflection width to match the length standard determined by the laser length measurement system, which is performed before pattern writing, the length standard determined by the laser length measurement system itself was changed according to the scaling rate. A charged particle beam drawing method characterized by: 3. When adjusting the beam deflection width to match the length standard determined by the laser length measurement system, when the stage is moved, a correction is made to the amount of movement according to the scaling rate, and the beam deflection amount is adjusted to the corrected standard amount. A charged particle beam writing method characterized by combining 4. Claim 1 in which the incident angle of the laser beam from the laser length measurement system to the reflecting mirror attached to the stage is varied.
Charged particle beam writing method described in .