JPS62273718A - Charged particl beam lithography - Google Patents

Abstract

PURPOSE:To momentarily decide the propriety of data by so forming lithography pattern data that the number of lithography figures to be drawn by beam deflecting means becomes even or odd and processing to draw a desired pattern on the basis of chip data of an integrated circuit composed as an assembly of the data. CONSTITUTION:Cell data 1 stored in a magnetic disk is transferred to a cell data buffer 2, temporarily stored in the buffer so that figure data 3 is translated by a pattern decoder 4 to control a variable beam forming unit 6, a main deflecting position and a sub-deflecting position are controlled on the basis of lithography data 8 to draw a desired pattern. Here, the decoder 4 adds 1 to a counter for counting the data whenever the figure data for forming a unit lithography region is read out. when the least significant bit (LBS) of the counter is '0' and the number of the figure data contained in the lithography region is even, the fact that the pattern data is correctly transferred and supplied to the lithography process is monitored.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Object of the Invention] (Field of Industrial Application) The present invention is a method for applying patterns of semiconductor integrated circuits such as LSIs to masks or wafer samples at high speed and with high precision. The present invention relates to a drawing method using a charged beam such as an electron beam for drawing.

(Prior Art) LSI patterns have become increasingly fine and complex in recent years, and as a device for forming such patterns, for example, an electron beam lithography device is used as one of the charged beam lithography devices.

Here, explanation will be given using this electron beam lithography apparatus as an example.

When drawing a desired pattern using the electron beam drawing apparatus, the design data generated by an LSI design tool such as CAD cannot normally be used as drawing data for the drawing apparatus in its original format. The reasons for this are: ■Design data is generally expressed in polygons, whereas data used for electron beam writing can only be of basic shapes such as trapezoids or rectangles; ■If there is overlap between shapes, multiple exposure may occur. This is due to the fact that the area must be divided into unit drawing areas for performing drawing processing.

Therefore, the above design data is subjected to, for example, contouring processing to remove multiple exposures, and then divided into basic figures such as rectangles and trapezoids for each unit drawing area determined by the beam deflection area, and drawing unit figures. Drawing pattern data related to integrated circuits is generated by the process of making graphic data that is false to the drawing device and stored in a storage medium.

Then, the drawing pattern data is read out for each unit drawing area and temporarily stored in a pattern data buffer, and while decoding this data, the beam deflection means controls the beam position and beam shape to draw a desired pattern. Processing is performed.

However, there are problems when performing drawing processing in such a process.

In other words, even if defective drawing pattern data is transferred to the pattern data buffer due to noise or malfunction when reading data from the storage medium when transferring the drawing pattern data stored in the storage medium to the pattern data buffer. Since there is no step to determine whether the data is good or bad, the drawing process is performed based on defective drawing pattern data, and the desired pattern is not obtained, resulting in abnormal patterns such as pattern omissions.

Furthermore, the operator cannot recognize abnormalities that occur during such drawing processing, and as a result, it takes a lot of time to detect that the cause of the defective pattern is a problem during data transfer. This requires a lot of effort, lowers the operation rate of the electron beam lithography system, and reduces the LS
There were problems such as a decrease in productivity.

However, the above-mentioned problems will be solved in the future due to the rapid progress of LSI, which will lead to finer patterns and improved integration, which will improve the reliability of LSI patterns drawn with the electron beam lithography equipment and increase the operating efficiency of the equipment. It becomes a big gap.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances, and its purpose is to instantly determine the quality of drawing pattern data transferred from a storage medium in a charged beam drawing device. The object of the present invention is to provide a charged beam drawing method that can improve the reliability of drawn patterns and the productivity of LSI.

[Structure of the invention]

Means for Solving Problem C) The gist of the present invention is to generate drawing pattern data by specifying that the number of drawing figures included in a unit drawing area is an even number or an odd number, and to generate the drawing pattern data. from the storage medium to the pattern data (when transferring it to the sofa and performing drawing processing, count the number of drawing figures included in the above area i, determine whether the count value is the number specified above, and perform the above drawing. The object of the present invention is to inspect the quality of pattern data and detect defects in drawing in real time.That is, the present invention divides the chip area of a semiconductor integrated circuit into unit drawing areas determined by the beam deflection area of a charged beam optical system.
In a charged beam drawing method that draws a pattern in the entire desired area by repeating a process of drawing a desired pattern using a beam deflection means while controlling the position of the area,
When generating drawing pattern data for all unit drawing areas related to the desired area from the design pattern data of the semiconductor integrated circuit, the drawing is performed so that the number of drawing figures that can be drawn by the beam deflection means is an even number or an odd number. The pattern data is configured, chip data of the integrated circuit is constructed as a collection of the drawing pattern data, and a desired pattern is drawn based on the assigned chip data, and the drawing pattern data of the unit drawing area is When generating the drawing pattern data, the drawing pattern data related to the unit drawing area is constructed by combining a drawn figure that contributes to the pattern drawing process and a pseudo drawn figure that does not contribute to the drawing process.

Further, a storage medium for storing chip data of the integrated circuit; a pattern data buffer for temporarily storing drawing pattern data for each unit drawing area from the storage medium; and a drawing data buffer stored in the pattern data buffer. In a charged beam lithography apparatus having a data decoding means for reading out pattern data, further decoding the pattern data, and issuing a command to the beam deflection means, it is determined whether the number of figures to be drawn constituting the drawing pattern data is an even number or an odd number. By making this determination, the quality of the drawing pattern data is inspected and drawing processing is performed.

(Function) According to the present invention, when performing drawing processing based on drawing pattern data stored in a storage medium, errors that occur when data is transferred from the storage medium to the pattern data buffer are detected in real time. You can monitor whether the drawing process is being executed correctly. This eliminates the need for a lot of time and effort that was previously required when an abnormal pattern occurs, and as a result, increases the operation rate of the electron beam lithography system and improves LS.
The productivity of I can be improved.

Furthermore, the mechanism for inspecting the quality of the drawing pattern data described above can be realized extremely easily without increasing the manufacturing cost of the apparatus.

(Example) Hereinafter, the present invention will be explained along with examples. FIG. 1 is a block diagram showing a schematic configuration of an apparatus used in this embodiment.

Cell data 1 indicating a drawing pattern is stored in a cell data buffer 2. Drawing data 3 consisting of a pointer pointing to a drawing position and cell data is interpreted by a drawing data decoder 9, each piece of cell data 7 is sent to a cell data buffer 2, and designated cell data is read from the cell data buffer 2. Subfield number 10 is sent to the main deflector controller 11 and offset data 14 is sent to the sub deflector controller 15. The pattern data decoder 4 interprets the graphic data 3 and sends subfield positioning data to the main deflector driver 12. The electron beam is deflected and scanned by the main deflector 13 to a designated subfield position.

The sub-deflector controller 15 receives the offset data 14 from the drawing data decoder 9 and the cell size 18 from the cell data buffer 2, generates a sub-deflector scanning control signal, and receives the sub-deflector driver 16. generates a sub-deflection signal, and uses the sub-deflector 17 to position the figure drawing position in the sub-field.

FIG. 2 shows the process of generating data for performing drawing processing with the above-mentioned apparatus. Usually, an LSI pattern is designed using a CAD system, and here the pattern is a polygon 21.22 as shown in Figure 3.
It is a data system in which there is an overlap between patterns as shown by 23.

In order to make LSI data in such a format acceptable to an electron beam lithography system, the host computer converts it into data shown in Figure 3 (b).
)ζ As shown in FIG. 3(C), the figure is contoured and the beam multiple exposure area is removed, and the unit drawing area 24.25 is determined from the beam deflection area as shown in FIG. 3(C).
The drawing pattern data 31 to 37 consisting of cell data and drawing data obtained by dividing into drawing figures that can be created by the variable beam shaper 6 as shown in FIG. 3(d) are stored on a magnetic disk. When generating the cell data 1 of a unit drawing area consisting of an odd number of drawing figures such as the drawing figures 31 to 33 included in the area 24, the drawing figures 31 to 33 are accumulated. In addition to the figure data 31 to 33 expressed by the figure type 41 indicating the figure shape, the beam irradiation amount 42, the figure position @43 indicating the beam irradiation position, and the figure size 44, as shown in FIG. 4(b), respectively. Figure 4(a)
As shown in FIG. 2, the cell data 1 is generated from an even number of figure data and pseudo data D indicating by the figure type 41 or the beam irradiation amount 42 that the figure is not actually irradiated with a beam.

In addition, a drawing figure 34 included in the unit drawing area 25
If it is originally composed of an even number of drawing figures as shown in 37 to 37, all the cell data related to the desired area is constructed by the step of generating cell data 1 from the figure data 34 to 37 without adding the above-mentioned pseudo data. Drawing pattern data is generated such that the number of graphic data to be drawn is an even number.

When performing a drawing process based on the drawing pattern data generated in this way, the cell data 1 accumulated on the magnetic disk is transferred to the cell data buffer 2 and temporarily stored in the cell data buffer. The pattern decoder 4 interprets the generated graphic data 3 and controls the variable beam shaper 6, and also controls the main deflection position and the sub-deflection position based on the drawing data 8 to draw a desired pattern. Here, each time the pattern data decoder 4 reads out graphic data constituting a unit drawing area,
A counter that counts the graphic data is incremented by one. And the least significant bit (L8B) of the above counter
is "0" and the number of figure data included in the unit drawing area is an even number, so it is possible to monitor whether the drawing pattern data is correctly transferred and subjected to drawing processing. As a result, abnormalities in the drawing process can be detected extremely easily.

Note that the present invention is not limited to the embodiments described above, and can be implemented with various modifications without departing from the gist thereof.

For example, the schematic configuration of the electron beam lithography apparatus is not limited to the embodiments and can be modified as appropriate. Furthermore, although the present embodiment has been described using an electron beam as an example, the beam is not limited to an electron beam, and can be applied to a charged beam including an ion beam. Furthermore, the drawing method may be a two-stage deflection method that combines main and sub-deflection, or a single-stage deflection method, and a scanning method using a thin circular beam of the sheet shot method using a variable shaped beam can also be applied. be.

〔Effect of the invention〕

According to the present invention, it is possible to improve the reliability and productivity of drawn patterns.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a schematic configuration of a device used in an embodiment of the present invention, Fig. 2 is a schematic diagram showing the process of generating drawing pattern data, and Fig. 3 is a diagram showing figures up to the generation of drawing pattern data. FIG. 4, a schematic diagram showing division, is a diagram for explaining the structure of drawing data. ]...Cell data, 2...Cell data buffer, 3
...Graphic data, 4...Pattern data decoder,
5... Variable beam former driver, 6... Variable beam former, 7... Cell data name, 8... Drawing data, 9... Drawing data decoder, 10... Subfield number, 11... Main deflector controller, 12...
- Main deflector driver, 13... Main deflector, 14...
Offset data, 15... sub-deflector controller,
16... Sub-deflector driver, 17... Sub-deflector, 1
8... Cell size, 21.22... Design data, 2
3...Multiple exposure area, 24.25...Unit drawing area, 31-37...Drawing figure. Agent Patent Attorney Nori Ken Yudo Takehana Kikuo Figure 1 Figure 2 Figure 3

Claims (6)

[Claims] (1) The chip area of the semiconductor integrated circuit is divided into unit drawing areas determined by the beam deflection area of the charged beam optical system, and the desired pattern is drawn by the beam deflection means while controlling the position of the area, which is repeated. In a charged beam drawing method for drawing a pattern of an entire area, a drawing figure that can be drawn by the beam deflection means when generating drawing pattern data of all unit drawing areas related to the desired area from design pattern data of the semiconductor integrated circuit. The drawing pattern data is configured such that the number of the drawing pattern data is an even number or an odd number, chip data of the integrated circuit is constructed as a collection of the drawing pattern data, and a desired pattern is written based on the chip data. A charged beam drawing method characterized by the following. (2) When generating the drawing pattern data for the unit drawing area, the drawing pattern data related to the unit drawing area is generated by combining a drawing figure that contributes to the pattern drawing process and a pseudo drawing figure that does not contribute to the drawing process. 2. The charged beam drawing method according to claim 1, wherein the data is constructed and the drawing process is performed based on the data. (3) Pseudo drawing figures that do not contribute to the drawing process are:
3. The charged beam drawing method according to claim 2, wherein the drawn figure contributing to the drawing process is distinguished from and expressed by an index indicating the type of the figure. (4) Pseudo drawing figures that do not contribute to the drawing process are:
3. The charged beam drawing method according to claim 2, wherein the charged beam drawing method is distinguished and expressed by an index indicating the amount of charged beam irradiation. (5) a storage medium that stores chip data of the integrated circuit; a pattern data buffer that temporarily stores drawing pattern data for each unit drawing area from the storage medium;
In a charged beam lithography apparatus having a data decoding means for reading out the lithography pattern data stored in the pattern data buffer, further decoding the pattern data, and issuing a command to the beam deflection means, a lithography figure constituting the lithography pattern data is provided. 2. The charged beam lithography method according to claim 1, wherein the quality of the lithography pattern data is inspected for lithography processing by determining whether the number is an even number or an odd number. (6) The data decoding means includes means for counting the number of drawing figures constituting the drawing pattern data, and means for determining whether the number is even or odd based on the least significant digit of the count value. A charged beam drawing method according to claim 5, characterized in that: