JPH04199612A - Charged particle beam lithography - Google Patents

Abstract

PURPOSE:To contrive reduction in the amount of lithography data by a method wherein, when a pattern is drawn, a patterning is conducted on material by deflecting a charged particle beam on the fine equally split field data of necessary combination. CONSTITUTION:Each pattern drawn on the material 4 to be patterned is field- split by a field-split circuit 13', the split pattern is converted into drawing data by a control device 14 and stored in a drawing data memory 15'. When a pattern is drawn, each address of the drawing data memory 15 is called up by a call circuit 19, and the drawing data of the split field is sent to the control device 14. The control device 14 outputs the positional data and dimensional data in X-Y direction of each pattern in the split field, and a deflection signal forming circuit 11 makes the scanning signal in X-direction and the scanning signal in Y-direction based on the respective data. These scanning signals are sent to X-direction and Y-direction positioning deflectors 3A and 3B, an electron beam is scanned on the prescribed part of the split field, and a pattern is drawn. As a result, the amount of drawing data can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a charged particle beam drawing method that reduces the amount of stored data and improves drawing accuracy.

(Prior art) One of the charged particle beam drawing methods is to move a stage intermittently so that each drawing field on the material is sequentially on the optical axis, and while each stage is stopped, charging for drawing is carried out. There is a so-called step-and-repeat method in which a pattern is drawn by scanning a field with a particle beam.

In an electron beam lithography apparatus employing such a step-and-repeat method, the deflection aberration increases as the deflection angle of the electron beam increases, so the lithography accuracy near the field boundary is lower than the lithography accuracy near the center of the field. In order to solve this problem of drawing accuracy near field boundaries, the present inventors developed a drawing method called field shifting. The drawing method will be described below using three-time field shifting as an example.

FIG. 3 shows a schematic diagram of an electron beam lithography apparatus. In the figure, 1 is an electron gun, 2 is a focusing lens, 3A is a deflector for positioning in the X direction, 3B is a deflector for positioning in the Y direction, 4
is a material to be drawn, 5 is a stage, 6 is a stage moving mechanism,
7.9 is an amplifier, 8.10 is a DA converter, 11 is a deflection signal generation circuit, 12 is a magnetic disk, 13 is a field division circuit, 14 is a control device, 15 is a drawing data memory, 1
6 is a control signal generation circuit for blanking, 17 is a blanking electrode, and 18 is a blanking aperture.

In such a device, before pattern drawing, the control device 1
In response to the command 4, batten data of each pattern to be drawn on the material 4 to be drawn is called out from among the data stored in the magnetic disk 12 and sent to the field division circuit 13. The field division circuit 13 divides each pattern data to be drawn on the drawing material 4 into, for example, 4th, 5th, 5th, 5th, 4th, 5th, 4th, 5th, 4th, 5th, 5th, 4th, 5th, 4th, 5th, 4th, 5th, 4th, 5th, and 5th.
As shown by the broken lines in Figure 6, fields are divided by shifting their positions. Note that the solid lines in the figure indicate the boundaries of the chips.

The pattern data divided into three types is converted into drawing data by the control device 14 and stored in the drawing data memory 15.

When drawing a pattern, first, the stage moving mechanism 6 moves the stage 5 according to a command from the control device 14 so that the center of the field F1 shown in FIG. 4 is on the axis of the electron optical system. Then, the control device 14 first sequentially calls out the drawing data divided into fields as shown in FIG. 4 from the drawing data memory 15. First, field F
X, Y direction position data and X, of each pattern in 1.
The Y-direction dimension data is sequentially retrieved and each data is sent to the deflection signal generation circuit 11. The deflection signal generating circuit 11 generates an X-direction scanning signal and a Y-direction scanning signal based on the respective data. Note that the X direction and Y direction scanning signals are as follows:
The amount of electron beam irradiation applied to the drawing material 4 is the required amount (
The amount of electron beam irradiation used to draw the pattern is 1/3. The X-direction scanning signal is sent to the DA converter 8.
The Y-direction scanning signal is sent to the X-direction positioning deflector 3A via the amplifier 7, and the Y-direction scanning signal is sent to the DA converter 10. The signal is sent via the amplifier 9 to the Y-direction positioning deflector 3B. As a result, electron gun 1
The electron beam emitted from the field F1 and focused by the focusing lens 2 scans a predetermined location on the field F1.

When the drawing of the field F1 is completed, the control device 14
A blanking signal is sent from the blanking control signal generating circuit 16 to the blanking electrode 17, and the electron beam is blanked.

At the same time, based on a command from the control device 14, the stage moving mechanism 6 moves the stage 5 so that the center of the field F2 of the material 4 is on the axis of the electron optical system. Similarly, by turning off the blanking at the start of pattern drawing, field F2 is drawn. Similarly, field Fi + F4 +
F5 + ..., F1□+F18.・・・・・・
...+F63+F64 is drawn.

Next, in response to a command from the control device 14, the stage moving mechanism 6 moves the center a of the field F Is' of the reference size including the field F1'' shown in FIG. The stage 5 is moved so that the point whose coordinates are -Δ/2.Y, +Δ/2) is on the optical axis.
As shown in FIG. 5, the field-divided drawing data is sequentially called. First, the X and Y direction position data and dimension data of each pattern in the field F1° are called,
The respective data are sent to the deflection signal generation circuit 11. The deflection signal generation circuit 11 generates an X-direction scanning signal and a Y-direction scanning signal based on the respective data, and sends the X-direction scanning signal to a DA converter 8. The Y-direction scanning signal is sent to the X-direction positioning deflector 3A via the amplifier 7, and the Y-direction scanning signal is sent to the DA converter 10. It is sent via the amplifier 9 to the Y-direction positioning deflector 3B. still,
At this time as well, the X-direction and Y-direction scanning signals are created so that the amount of electron beam irradiation irradiated onto the material is 1/3 of the required amount. In this way, field F1° is drawn.

At the same time, in response to a command from the control device 14, the stage moving mechanism 6 moves the stage 5 so that the center of a field F25' having a reference size including the field F2° shown in FIG. 5 is on the optical axis. let Then, in the same manner as described above, the field F2° is drawn. Thereafter, in the same manner, fields F3', F4'', F,'', F
b', F7°.

When drawing Fa' and F9°, centers c, d, and e of fields of standard size including the respective fields.

The stage 5 is moved so that f, g, h, and i are sequentially placed on the forward axis, each time each field F, ".

F4'',...F9' are drawn.Furthermore, for other chips, a similar series of steps is performed, and in response to instructions from the control device 14, the stage moving mechanism 6 moves as shown in FIG. Field FI ”+F2 ”Field of standard size including gF, ゛, respectively F'ts'+F
25" r Center a' of F35'° (as shown in Figure 8, the point whose coordinates are X, +△/2.Yo-△/2)
, b', c', . . . are sequentially moved on the optical axis. Then, in the same manner as above, each time □ each field Fl ``r F2 ''+
F, “°, . . . ” is drawn.

In each drawing by the three-time field shift described above, since the field boundaries within each chip are different, the drawing accuracy within each chip is averaged. Therefore, it is possible to solve the conventional problem of deterioration in drawing accuracy near field boundaries.

(Problem to be Solved by the Invention) However, the pattern drawn in each chip on the material is usually composed of tens of thousands to hundreds of thousands of figures, and If the pattern data drawn on the drawing material 4 is divided into three types of fields as described above, the amount of drawing data becomes enormous. Therefore, the storage capacity of the drawing data memory 15 may be exceeded. One possible solution to this problem is to use a memory with a large capacity, but such memory is extremely expensive. or,
As the amount of drawing data increases, the time required for data transfer, etc. increases, and the total drawing time increases.

The present invention is aimed at solving such problems.

(Means for Solving the Problems) For this purpose, the present invention divides data necessary for pattern writing into finer equal parts than a reference field that can draw a pattern on a material by the deflection of an electron beam. In addition to storing field drawing data, the data necessary for pattern drawing is virtually divided into two or more fields with different boundaries, and the center of the reference field including each of the virtually divided fields is charged. Each time the material is moved so that it is on the axis of the particle beam optical system, the drawing data of the finely divided fields of the combination corresponding to each of the virtually divided fields is called, and the charged particle beam is drawn based on the data. By deflecting the material, a pattern is drawn on the material.

(Embodiment) FIG. 1 is a schematic diagram of an electron beam lithography apparatus shown as an embodiment of the present invention. In the figure, the same components as in FIG. 3 are denoted by the same numbers.

13' is a field division circuit, 15- is a drawing data memory, 19 is a calling circuit, and 20 is a drawing area address memory.

In such a device, before pattern drawing, the control device 1
4, among the data stored in the magnetic disk 12, pattern data of each pattern to be drawn on the drawing target material 4 is called, and the field dividing circuit 13''
sent to. The field dividing circuit 13' divides each pattern to be drawn on the drawing material 4 into fields, for example, as shown by broken lines in FIG. The divided pattern data is converted into drawing data by the control device 14 and stored in the drawing data memory 15'. The drawing area address memory 20 also contains field commands representing each field divided as shown in FIGS. When forming the divided fields by appropriately combining them,
The address number of the drawing data memory 15' in which each pattern data in the divided fields to be combined is stored is stored.

When drawing a pattern, according to a command from the control device 14,
The stage moving mechanism 6 moves the stage 5 so that the center a (see FIG. 7) of a field of a reference size including the field F1' is on the optical axis. Then, the control device 14 first sends the field F to the calling circuit 19.
1. Sends field command designation signal. The calling circuit 19 specifies an address below the address where the field command is stored, and sequentially calls the address numbers stored there. Then, each address of the drawing data memory 15' corresponding to the called address number is addressed, and the drawing data of the divided field Fil corresponding to the field F1° is sent to the control device 14.

The control device 14 sends X and Y direction position data and X and Y direction dimension data of each pattern in the divided field Fll to the deflection signal generation circuit 11. The deflection signal generation circuit 11 generates an X-direction scanning signal and a Y-direction scanning signal based on the respective data. As described above, the X-direction and Y-direction scanning signals are created so that the amount of electron beam irradiated onto the material is 1/3 of the required amount.

The X direction scanning signal is transmitted through the DA converter 8 and the amplifier 7.
The Y-direction scanning signal is sent to the direction positioning deflector 3A, and the Y-direction scanning signal is sent to the DA converter 10. Deflector 3 for Y direction positioning via amplifier 9
Sent to B. As a result, the electron beam emitted from the electron gun 1 and focused by the focusing lens 2 scans a predetermined location on the divided field F, and a pattern is drawn.

When the drawing of the divided field Fil is completed, a blanking signal is sent from the control device 14 to the blanking electrode 17 via the blanking control signal generation circuit 16,
The electron beam is blanked. At the same time, in response to a command from the control device 14, the stage moving mechanism 6 moves the stage so that the center a' (see FIG. 8) of a field of a reference size including fields F and 2 is on the optical axis. move it.

Next, the control device 14 sends a field command designation signal for the field F1° to the calling circuit 19. The calling circuit 19 specifies an address below the address where the field command is stored, and sequentially calls the stored address numbers. Then, each address of the drawing data memory 21 corresponding to the called address number is addressed, and a divided field Fll+F12+F2++F2 corresponding to the field F1'' is created.
2 is sent to the control device 14. The control device 14 divides the divided fields F l+, F r□+
The X and Y direction position data and the X and Y direction dimension data of each pattern in F21+F2□ are sent to the deflection signal generation circuit 11. The deflection signal generation circuit 11 generates an X-direction scanning signal and a Y-direction scanning signal based on the respective data. Furthermore, said X.

As described above, the Y-direction scanning signal is created so that the amount of electron beam irradiated onto the material is ⅓ of the required amount. The X-direction scanning signal is sent to the DA converter 8. Amplifier 7
The Y-direction scanning signal is sent to the X-direction positioning deflector 3A via a DA converter 10° amplifier 9 to the Y-direction positioning deflector 3B. As a result, the electron beam emitted from the electron gun 1 and focused by the focusing lens 2 is divided into divided fields F11. Fl. +F2++ A predetermined location on F22 is scanned and a pattern is drawn in each field.

Next, the stage is moved so that the center of the field F1 is on the optical axis, and the divided fields corresponding to the field F1 are divided into Fll+F12=F13+F21+
F22+ F23+ F31+ F32+
Drawing of F33 is performed as described above. At this time as well, the amount of electron beam irradiation is 1/3 of the required amount.

Thereafter, similarly, the stage is sequentially moved so that the center of each reference field for drawing each field shown in FIGS. 4, 5, and 6 is on the optical axis, and each time, each field is The drawing data of each finely divided field shown in FIG. 2 corresponding to the above is called as described above, and a combination area of the equally divided fields is drawn. Note that the amount of electron beam irradiation when drawing each field is 1/3 of the required amount.

In the above embodiment, the same chip has three different boundaries.
Each field is virtually divided into two fields, and each field generated by the virtual division is drawn into a combination of finely divided fields corresponding to each field, with the electron beam irradiation amount being 1/3 of the required amount. However, the present invention is not limited to this, and the same chip may be virtually divided into N (N≧2) fields each having a different boundary, and the fine division may be performed in combinations corresponding to each field generated in the virtual division. It is possible to write each field by reducing the electron beam irradiation amount to 1/N of the required amount.

Further, the present invention can also be applied to drawing using an ion beam.

(Effects) The present invention divides the data necessary for pattern drawing into finer equal parts than a reference field that allows a pattern to be drawn on a material only by deflection of an electron beam, stores the finely divided drawing data, and stores the finely divided drawing data at the time of pattern drawing. , based on the required combination of finely divided field data, the charged particle beam is deflected to draw a pattern on the material, so compared to the conventional method, the data required for pattern drawing is reduced to more than N types. Since it is not divided into two parts, the amount of drawing data is significantly reduced. Therefore, the capacity of the drawing data memory is small.
No cost. Furthermore, since the amount of data is small, the time required for data transfer etc. is reduced, and the total drawing time is reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an electron beam lithography system shown to explain the present invention, FIG. 2 is a diagram used to explain the present invention, and FIG. 3 is a schematic diagram of a conventional electron beam lithography system. 4th.
5. 6. Figure 7.8 is a diagram used to explain electron beam lithography. DESCRIPTION OF SYMBOLS 1... Electron gun, 2... Focusing lens, 3A... Deflector for positioning in the X direction, 3B... Deflector for positioning in the Y direction, 4... Material to be drawn, 5... Stage, 6...
Stage movement mechanism, 7, 9... Amplifier, 8.10...
・DA converter, 11... Deflection signal generation circuit, 12...
・Magnetic disk, 13.13'...Field division circuit, 14...Control device, 15, 15°...Drawing data memory, 16...Blanking control signal generation circuit, 17...Blanking Ranking electrode, 18...Blanking aperture, 19...Calling circuit, 20...Drawing area address memory "63 F-, F"l, F2

Claims (1)

[Claims] The data necessary for pattern drawing is divided evenly into smaller fields than a reference field that allows a pattern to be drawn on a material only by deflection of an electron beam, and the finely divided field drawing data is stored, and the data necessary for pattern drawing is , each time the material is virtually divided into two or more fields with different boundaries, and the material is moved so that the center of the reference field containing each of the virtually divided fields is on the axis of the charged particle beam optical system. , a pattern is drawn on the material by calling the drawing data of the finely divided fields of the combination corresponding to each of the virtually divided fields and deflecting the charged particle beam based on the data. Charged particle beam writing method.