JPS63133525A - Charged beam aligner - Google Patents

Abstract

PURPOSE:To dispense with shot splits of the second time and succeeding times, to increase substantially the shot split speed and to contrive the improvement of the lithography throughput by a method wherein graphic data, which are repeatedly used, are split and the obtainable shot data are stored in a shot data memory. CONSTITUTION:A shot split circuit 11 interprets data from a computer and so on and performs a shot data split and after shot data are written in an FIFO buffer 13, the shot data are sent to a decode circuit 15 through a data selector 14. The shot data are interpreted in the circuit 15 and are respectively transferred to a deflecting system 16 for shot form control and a deflecting system 17 for shot position control. If the interpretation in the short split circuit 11 is a registering, the shot splid data are registered in a shot data memory 12 and if the interpretation is a reference, the registered data of the memory 12 are sent to the decode circuit 15. In this case, lithography position information (x) and (y) and array information (x), (y), (px), (py), (nx) and (ny) are sent from the shot split circuit 11 and the circuit 15 performs an interpretation of the shot data while modifying a shot position.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a charged beam exposure apparatus that forms LSI patterns on masks, wafers, etc. A charging machine with an improved variable shaping beam method that draws graphic data while dividing it into shots.
This invention relates to optical devices.

(Prior Art) In recent years, electron beam exposure apparatuses are increasingly required to be faster and more accurate, and variable shaped beam type electron beam exposure apparatuses have been developed to meet these demands.

FIG. 13 is a diagram schematically showing a schematic configuration of a variable shaped beam type electron beam exposure apparatus and a drawing method employed therein. The electron beam emitted from the electron gun 1 is cut into a rectangular shape by the first shaping aperture 2, and after this rectangular cut image is deflected by the shaping deflector 3, it is projected onto the second shaping aperture 174. be done. The optical pattern formed by this projected image and the second shaping aperture 4 is further deflected by the sub-deflector 5 and the main deflector 6, and then projected onto the sample to be exposed 7 to draw a desired figure.

The sub-deflector 5 is used to position and shoot a relatively narrow area at high speed, and the main deflector 6 is used to position the area to be deflected by the a1 deflector 5. In addition, in the figure, the molded deflector 3. Electrostatic 8-pole deflectors are used for both the sub-deflector 5 and the main deflector 6, but in other cases (for example, static 1!4
There are also polar deflectors, etc.).

FIG. 14 shows an example of the shape of a shot obtained by such a variable shaped beam type electron beam exposure apparatus. In addition to the rectangle whose vertical and horizontal dimensions are variable as shown in Fig. 14(a), there are four types of triangles as shown in Fig. This image is obtained by controlling the shaping deflector 3 to deflect the image to an appropriate position in the second shaping aperture 4.

By the way, this type of electron beam exposure equipment! When drawing with , the amount of data after the shot division is several times to 10 times larger than the original figure data, depending on the LSI design rules and the maximum size of the variable beam that can be generated by the electron beam exposure device. It increases by about twice as much. The amount of shot data may reach several tens of megabytes. Generally, in an electron beam exposure apparatus, a magnetic disk device of approximately several hundred megabytes, which has a large capacity, relatively high access speed, and is inexpensive, is used to store drawing data. In electron beam exposure equipment used for production purposes, it is necessary to always register several dozen types of drawing data as a library, so instead of the shot data after division, which increases the amount of data, the image data before division is stored on the magnetic disk. A commonly used method is to store it in the device, transfer it to the electron beam exposure device via a control device such as a computer at the time of writing, and write while dividing it using a built-in shot division circuit.

However, this type of device has the following problems. In other words, recent LSIs have become more highly integrated, and the number of graphics per chip has increased significantly, reaching 108
It's reaching the plateau. In addition, in electron beam exposure equipment,
There is a growing demand for drawing at speeds of 1 chip/second or higher.

For example, when drawing lXl0' chips at a rate of 1 chip/sec, and assuming that each graphic consists of 5 shots on average, the shots must be divided one after another at a rate of 200 ns/shot. No. This speed is extremely difficult to achieve by using conventional shot division circuit circuit technology as is. For example, if you try to increase the shot decomposition speed by multiplexing the shot division circuit, what about the circuit? 1! It was complicated, expensive, and had cost problems, as well as various technical problems. Under these circumstances, the writing speed is ultimately determined by the shot dividing speed of the shot dividing circuit, which poses a problem in improving the writing throughput.

(Problems to be Solved by the Invention) As described above, in the conventional variable shaped beam type electron beam exposure apparatus, the writing speed is determined by the shot dividing speed of the shot dividing circuit, and this is a factor that hinders the improvement of writing throughput. It had become.

This problem also applies to ion beam exposure apparatuses that use ion beams instead of electron beams.

The present invention has been made in consideration of the above circumstances, and its purpose is to supply shot data at a speed that does not limit the drawing throughput even to advanced LSIs, which are becoming increasingly highly integrated. It is an object of the present invention to provide a charged beam exposure apparatus using a variable shaping beam method that can improve drawing throughput.

[Structure of the Invention] (Means for Solving the Problems) The gist of the present invention is to provide a shot data memory for storing shot data, and to divide graphic data that is used repeatedly into one shot. .

That is, the present invention divides the graphic data transferred from the control device into shot data, and in a charged beam exposure VRR using a variable shaping beam method, which draws a desired pattern on the sample based on the shot data, the graphic data is charged. a shot dividing circuit that divides the shot data into variable-shaped shot data that can be generated by a beam optical system; a shot data memory that stores the data when the shot data divided by this circuit is a predetermined figure or a group of figures;
A data buffer section that temporarily holds the shot data when the above-mentioned shot data is not a pre-designated figure or a group of figures, and a data buffer section that selectively stores the shot data corresponding to the figure to be drawn from the above-mentioned shot data memory or data buffer section. A decoder section is provided for reading the data and generating deflection information for setting the shape and irradiation position of the charged beam based on the data.

Further, the characteristic means adopted by the present invention are as follows: (1) A shot data memory is provided which can sequentially store data divided into shots from graphic data by a shot division circuit and can read data randomly from any specified position. establish.

(2) Control information is included in the graphic data to control registration in the shot data memory, reading of shot data from the shot data memory, addition of necessary processing, and use for drawing.

(3) While reading shot data from the shot data memory and using it for drawing, a function is provided to divide and store new graphic data using a shot division circuit.

That's true.

(Function) Based on the control information included in the graphic data, the shot data obtained by dividing by the shot division circuit is stored in the shot data memory. Read the data and use it for drawing.

While referring to the shot data memory, the shot division circuit divides another figure. As a result, graphic data that is repeatedly used only needs to be divided into one shot, and the overall number of shot divisions can be reduced.

(Example) Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 shows the main structure of an embodiment of the present invention, and is a block diagram showing a processing system up to sending deflection information to a deflection system based on input graphic data. In the figure, 11 is a variable-shaped shot division circuit that can generate graphic data transferred from a control device such as a computer using an electron optical system, 12 is a shot data memory, and 13 is a first-in, first-out FIFO.
buffer; 14 is a data selector that selects data to be read from the scimit data memory 12 or FIFO buffer 13; 15 is a decoding circuit that generates internal information from shot data; 16 is a deflection system for shot shape control;
14 is a deflection system for shot position control.

FIG. 2 is a diagram showing a specific configuration of the shot data memory 12, in which 21 is a memory bank, 22 is an address register (ADRI) of the memory bank 21, 23 is an index table, and 24 is an address register (ADRI) of the index table 23. ADR2), 25 is the end register (E
26 is a comparator (CMP).

Further, FIG. 3 shows an example of representation of shot data used in this embodiment. Figure 3 (a) shows a rectangle; Figure 3 (b'
l~(+3) represents a triangle, and these represent the five types of shot data (Fig. 14 (a) used in the explanation of the conventional example).
1 to (e)), respectively. Each shot is expressed in 8 bytes, the first byte is used as a shot code to represent the type of shot, the 3rd to 6th bytes represent the x, y coordinates of the shot reference apex, and the 7th byte is the width of the shot. The eighth byte represents the height h of the shot.

Graphic data and shot data memory control information transferred from a control device such as a computer are shown in FIGS. 4 and 5, respectively. The types of graphic data are as shown in Figure 4 (
There is a rectangle in (a), a triangle in (b), and a trapezoid in (C). The first byte of the graphic data represents a graphic code, the next byte represents the length of the representation data, and the third and subsequent bytes represent vertex coordinates, width, height, etc. Looking at the figure style code in more detail, in the case of figure data, the upper 4 bits are all O's and the lower 4 bits represent the figure style. Conversely, in the case of shot data memory control information, the lower 4 bits are all set to 0.
The upper 4 bits represent the type of control. That is, 1
When expressed in hexadecimal notation, the figure-like code of the figure data is in the form of OX, and the figure-like code of the shot data memory control information is in the form of XO.

Now, the rectangle in FIG. 4(a) has a figure-like code of "01", a data length of "OA", a reference vertex's X and y coordinates, [ω
, expressed as height h. The triangle in Figure 4(b) has a figure-like code of ``02'', a data length of OA'', and a reference vertex of x.
−Y coordinate is expressed as 9 degrees ω and height is expressed as h. Here, negative values are also allowed for the width ω and the height h, and four types of triangles are expressed by combinations of the signs of ω and h. The trapezoid of the fourth factor (C) has a figure type code of "03", a data length of "OE", a reference vertex's X and y coordinates, and a value of 3 as shown in the figure, syl.

Expressed as Sy2. A trapezoid has two sides parallel to the y-axis. S
V2 also allows negative values, and can also represent a trapezoid in which the lower side of the two sides that are not parallel to the y-axis slopes upward to the right.

Registration of graphic data in the shot data memory and reference to graphic data registered in the shot data memory are performed in the fifth step.
This is performed based on the shot data memory control information shown in the figure. Figures 5(a) and 5(b) relate to reference, and Figure 5(C)
~(e) relates to registration. In the initialization shown in FIG. 5(C), the figure type code is "10" and the shot data memory is initialized. At the start of registration in Figure 5(d), the figure-like code is 1.
42011, the registration of figure (e) ends when the shape code is 3.
0'', the graphic data or graphic data group sandwiched between these two pieces of control information is divided into shots by the shot division circuit, and then registered in the shot data memory. The registration # designated at the start of registration in Figure Cd) and the end of registration in Figure Cd) is attached, and later reference is made by designating this registration #.

There are two ways to reference the graphic data registered in the shot data memory: the case shown in Fig. 5(a), in which the referenced graphic data or a group of graphic data is used for drawing only once, and the case in which it is arranged in an array and used repeatedly. There is a case as shown in FIG. In the case of (a), the figure-like code is “’ 40
” for the registration form and the drawing position.

The y coordinate is specified. In the case of (b), the figure-like code is '
50” to register # and standard drawing position coordinates x, y and x, y
The pitch pX, Dy of the directional arrangement and the number nx, ny of the arrangement in the x and y directions are specified.

In FIG. 1, the shot division circuit 11 interprets data transferred from a control device such as a computer. If the data is graphic data as shown in FIG. 4, after dividing the shot data and writing the shot data once into the FIFO buffer 13, the data is sent to the decoding circuit 15 through the data selector 14. The decoding circuit 15 interprets the shot data, generates a shot shape control signal and a shot position control signal, and transfers them to a shot shape control deflection system 16 and a shot position control deflection system 17, respectively. Here, the shot shape control deflection system 16 corresponds to the shaping deflector 3 of FIG. 13 used in the explanation of the conventional example,
The shot position control deflection system 17 corresponds to the sub-deflector 5 and main deflector 6 in the figure.

If the result interpreted by the shot division circuit 11 is shot data memory control information as shown in FIG.
3, but send it to the shot data memory 12 and register it with the specified registration #.

Further, if it is a reference, the data selector 14 is switched and the shot data registered in the shot data memory 12 is sent to the decoding circuit 15.

In this case, the shot dividing circuit 11 sends information X, y regarding the drawing position and information x, y regarding the array.

pX, DV, nX, ny are sent to the decoding circuit 15,
The decoding circuit 15 interprets the shot data while modifying the shot position based on this information.

Registration of graphic data in the shot data memory 12 and reference to the graphic data are performed by commands from the shot dividing circuit 11 when shot data control information is interpreted by the shot dividing circuit 11 as described above.

These operations will be explained in detail using FIG. 2 and in accordance with the flowcharts shown in FIGS. 6 to 8. The flowchart in FIG. 6 shows that the shot dividing circuit 11 in FIG.
This is the operation when the initialization control information shown in Figure (C) is interpreted. In step 1, the initialization code ゛' i o
” is detected, and then in step 2 the address register 22 of the memory bank 21 in FIG. 2 is cleared to 0, and in step 3 the address register 24 of the index table 23 in FIG. 2 is cleared to 0. In this way, the memory bank 21 and the index table 23 can be registered from an empty state.

The flowchart in FIG. 7 shows the operation when the shot dividing circuit 11 in FIG. 1 interprets the control information regarding registration shown in FIGS. 5(d) and (e). In step 4, the registration start code "20" is detected, and in step 5, the memory bank 21 shown in FIG. 2 is set to write mode. This memory bank 21 has a word length of 8 bytes and can store shot data at a ratio of 1al/address. Next, in step 6, the registration # included in the second byte of the control information is set in the address register 24 of the index table 23 in FIG. 2, and in step 7, the current address of the memory bank 21, that is, the address The contents of register 22 are written as the start address. At step 8, the address register 24 of the index table 23 in FIG. 2 is incremented by one in preparation for writing at the later end. In step 9, 2 bytes of graphic data are read in the shot division circuit 11 of FIG. 1, and in step 10, it is checked whether the code of the first byte is the registration end code "30".

If the first 1 byte code is not the registration end code, in step 11 the shot division circuit 11 of FIG. 1 reads the remaining graphic data based on the data length of the latter 1 byte of the 2 bytes read in step 9. Step 1
Step 2 divides it into shots, and step 13 registers it in the memory bank 21 of FIG. 2 while incrementing its address register 22. Once the registration is complete, go to step 9 again.
Returning to FIG. 1, the shot dividing circuit 11 of FIG. 1 reads 2 bytes of graphic data. The processes of steps 9 to 13 are repeated until the registration end code "30" is detected in step 10.

When the registration completion code "30" is detected in step 10, the process moves to step 14, and the address register 22 in FIG.
The contents of is written to the index table 23 as the end address of this registration.

Then, in step 15, the address register 24 is incremented by 1, and the process ends. In the above process, the graphic data sandwiched between the registration start control information and the registration end control information is divided into shots and stored in the memory bank 21 shown in FIG. 2, and the storage start and end addresses are set as shown in FIG. This means that it is registered in the index table 23.

The flowchart in FIG. 8 shows the operation when the shot dividing circuit 11 in FIG. 1 interprets the figure reference control information as shown in FIG. Then, in step 17, the code is
When it is determined that the reference figure data shown in FIG. 1A is the code '40'' which is used only once for drawing, the drawing positions X and y are sent from the shot division circuit 11 of FIG. 1 to the decoding circuit 15 in step 18. .Furthermore, if it is determined in step 17 that the code is ``50'', which is used to repeatedly draw the graphic data shown in FIG. 5(b) in an array, the shot dividing circuit 11 in FIG. Array information x, y, px, py, nx, ny is sent to the decoding circuit 15
sent to.

Next, in step 20, the memory bank 21 is set to read mode in order to read shot data from the memory bank 21 shown in FIG. In step 21, the registration # included in the second byte of the control information is set in the address register 24 of the index table 23 in FIG.

The contents read from the index table 23 in step 22 are loaded into the address register 22 of the memory bank 21 in FIG. That is, in steps 21 and 22,
The storage start address of the graphic data corresponding to the registration # specified by the second byte of the control information is set in the address register 22 of the metrebank 21. Next, in step 23, the address register 24 of the index table 23 in FIG. 2 is incremented by 1, and in step 2
4, the contents of the index table 23 are read out and set in the end register 25 of FIG. That is, in steps 23 and 24, the storage end address of the graphic data corresponding to the registration # specified by the second byte of the control information is set in the end register 25.

By the way, the index table 23 in FIG. 2 stores the contents of the address register 22 in a 1 word 2 byte configuration, and the address register 24 stores the registration # sent from the shot dividing circuit 11 in FIG. The bit-shifted contents are set to 1~. That is, in the index table 23 in FIG.
The storage start address of the figure table is registered, and <registration #> is registered.
The storage end address is registered at address x2+1. Second
The storage end address set in step 23 and 24 in the end register 25 shown in the figure is constantly compared with the contents of the address register 22 by the comparator 26 shown in FIG. 2 to check whether reading has ended. In step 25, shot data is read from the memory bank 21 of FIG. 2 and sent to the decoding circuit 15 through the data selector 14 of FIG.

In step 26, address register 2 of memory bank 21 is
2 is incremented by 1, and in step 27, completion is checked based on the comparison result of the comparator 26 of FIG. 2 mentioned earlier. While the content of the address register 22 is less than the content of the end register 25 in step 27, step 25 is again performed.
The shot data is read out from the memory bank 21, and when the contents of the address register 22 and end register 25 match, the reading ends.

Through the above processing, shot data is read from the shot data memory 12 from the storage start address to the storage end address of the graphic data corresponding to registration #, and the decoding circuit 1 of FIG.
Sent to 5. The decoding circuit 15 modifies the shot position based on the X, y, or x, V, pX, pV, nX, ny information received from the shot dividing circuit 11 in step 17 or step 18, and converts the shot data into shot data. decode.

Next, an example of actually drawing a pattern using the above-described Ill structure will be shown. Figure 9 shows a group of figures that are the basis of repetition,
FIG. 10 shows the pattern to be drawn. The pattern in Fig. 10 is the same as the first figure group consisting of a triangle and two rectangles shown in Fig. 9(a), in which nX5 figures are arranged in the X direction and r11 figures in the y direction. 2 shown in figure (b)
The second figure group consists of nX7 rectangles arranged in the X direction. In such a case, the two graphic groups shown in FIG. 9 are first registered in the shot data memory 12, and the data at that time is shown in FIG. 11.

In FIG. 11, ■ indicates that the shot data memory is initialized with initialization control information, and then, from the start of registration of ■ until the end of registration of □□□, ■ corresponds to the triangle 91 in FIG. The figure data, the figure data ``■'' corresponding to the rectangle 92, and the figure data ``■'' corresponding to the rectangle 93 are the shot dividing circuit 11.
and is registered in the shot data memory 12 as registration #1.

This procedure is already shown in the flowcharts of FIGS. 6 to 8. Next, in Figure 11, ■ 0 from the start of registration
By the end of the registration, the graphic data of ■ corresponding to the rectangle 94 in FIG. 9(b) and the graphic data of be registered. In this way, 1. The second graphic data group is stored in the shot data memory 12.
will be registered.

Data when drawing using these is shown in FIG. First, the graphic data of the first group in FIG. 9 is calculated from the coordinate values (Xs, Vs) in the X direction pitch px
s, y-direction pitch pys, number of X-direction rows nx6. y
Since it is drawn in an array with the number of directions ny6, the first
It will look like ◎ in Figure 2. As already explained, the code "50" at the beginning of ◎ indicates that the graphic data referenced from the shot data memory 12 is used in a 7-ray arrangement. Further, the second byte indicates reference registration #1 of the shot data memory 12.

Furthermore, the figure data of the second group in Fig. 9 is shown in Fig. 10 (X7
, 'T/7) to the X direction pitch pX7
.

Since it is drawn in a one-dimensional array with the number of rows in the X direction being nX7, it will look like 0 in FIG. 12. In ◎, only one is lined up in the y direction, so 0 is set in the py slot and 1 is set in the ny slot.

In O, the figure data of registration #2 is stored in shot data memory 1.
This indicates that it is to be referred to and used from 2.

According to the above method, the first group of figures in FIG.
Since the trouble of dividing the figures of the second group into shots ny6 times and nX7 times is saved, the effect is essentially the same as that of greatly improving the shot division speed, and drawing can be performed at a high throughput. That is, since the graphic data or graphic data group that has been once divided into shots and is to be used thereafter is stored in the shot data memory 12, there is no need to divide the shots from the second time onward, which has the effect of substantially increasing the shot division speed. . For this reason, it is possible to use ultra-high density, cutting-edge LS, which could not be supported by the conventional method of dividing it into individual parts.
I can now write at high throughput, and its usefulness is enormous. Moreover, this embodiment can be easily realized by adding the shot data memory 12 and other socket circuits to the conventional shot division mechanism. Furthermore, rather than registering all of the divided shot data in the shot data memory 12, it is selectively registered in consideration of the frequency of later use and the effect of reducing shot time through registration, so the memory also has a large capacity. There is also the advantage of not having to do so.

Note that the present invention is not limited to the embodiments described above. In the embodiment, the registered data is divided in advance, divided into shots, and registered in the shot data memory before being referenced during drawing. It is also possible to register it in the shot data memory. In short, the graphic data registration processing sandwiched between the graphic data and the control information for registration start and registration end, and the control information for graphic reference may be mixed in the drawing data, so that registration reference can be made arbitrarily, and This means that the data can be divided into shots and used as is.

Further, the configuration of the optical system of the electron beam exposure apparatus may be any one that obtains a variable shaped beam, and can be changed as appropriate according to specifications. Furthermore, the invention is not limited to electron beam exposure apparatuses, but can also be applied to ion beam exposure apparatuses. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] This has been detailed above. According to the present invention, with respect to graphic data that is used repeatedly, by storing the shot data obtained by dividing into the scissor data memory, there is no need to divide the data from the second time onwards, and the data can be effectively saved. This has the effect of increasing shot division speed.

Therefore, shot data can be supplied to a super-integrated LSI at a rate that does not limit the drawing speed, and the drawing throughput can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main structure of an embodiment of the present invention, FIG. 2 is a block diagram showing the specific structure of the shot data memory shown in FIG. 1, and FIG. 3 is a block diagram showing an example of shot data representation. FIG. 4 is a schematic diagram showing an example of representation of graphic data; FIG. 5 is a schematic diagram showing shot data control information; FIG.
8 to 8 are flowcharts showing the control procedure of the shot data memory, FIG. 9 is a schematic diagram showing a group of figures that are the basis of repetition, FIG. 10 is a schematic diagram showing an example of a drawing pattern, and FIGS. Figure 12 is a data representation of the drawing pattern in Figure 10, Figures 13 and 14 are for explaining the problems of the conventional technology, and Figure 13 is an illustration of a variable shaped beam electron beam exposure system. FIG. 14 is a schematic diagram showing the shape of a shot. DESCRIPTION OF SYMBOLS 11... Shot dividing circuit, 12... Shot data memory, 13... FIFO buffer, 14... Data selector, 15... Decoding circuit, 16... Deflection system for shot shape control, 17... ...Deflection system for shot position control, 21...Memory bank, 22.24...
Address register, 23... index table,
25... End register, 26... Comparator. Applicant's agent Patent attorney Takehiko Suzue U 舅＊sai use Fig. 14 fs3 Fig. 4 I-guchi 5th T21 Persaka β (Ai) Ko Ruwa 1111 I and 5 Ko Imashinkai 7-guchi No. 3

Claims (4)

[Claims] (1) In a variable shaped beam type charged beam exposure device that divides the graphic data transferred from the control device into shot data and draws a desired pattern on the sample based on this shot data, the graphic data is transferred to the charged beam optical system. a shot dividing circuit that divides the shot data into variable-shaped shot data that can be generated by the system; a shot data memory that stores the data when the shot data divided by this circuit is a prespecified figure or a group of figures; a data buffer section that temporarily holds shot data when the shot data is not a pre-specified figure or group of figures;
a decoder section that selectively reads shot data corresponding to a figure to be drawn from the shot data memory or data buffer section and generates deflection information for setting the shape and irradiation position of the charged beam based on the data; A charged beam exposure apparatus comprising: (2) The charged beam exposure apparatus according to claim 1, wherein the shot data memory stores the shot data sequentially and is read out randomly. (3) The graphic data transferred from the control device includes control information for controlling reading/writing of the shot data memory, such as registration in the shot data memory and reference to the memory, and is generated by the shot dividing circuit. 2. A charged beam exposure apparatus according to claim 1, wherein said shot data is registered in and referenced to a shot data memory based on said control information. (4) Registering the shot data in the shot data memory in parallel with dividing the figure data being drawn into shot data and using it for drawing based on control information included in the figure data. 4. A charged beam exposure apparatus according to claim 3, wherein shot data memory is registered.