JPS62273719A - Data verification in charged particle beam exposure equipment - Google Patents

Abstract

PURPOSE:To efficiently verify data by dividing an LSI data into figure groups which can be solely emitted by a charged particle beam, and displaying the figure containing a short side less than the minimum length allowable for the beam distinctly from other figure when displaying the figure group to enhance the verifying accuracy of the data. CONSTITUTION:In order to verify whether a basic figure is correctly generated or not, a basic figure and a lithography unit figure obtained by dividing the basic figure by a host computer are graphically displayed as a pattern display unit from the computer. In this case, the figures gl-g4 that the width and the height of the figure are larger than the length epsilon allowable by an electron beam lithography equipment are displayed by first color (e.g., green). the figures gamma1-gamma3 that one of the width an the height of the figure contains a side less than the length epsilon is displayed by hatching with second color (e.g., red) or solidly coating. Thus, a fine figure which causes the lithography accuracy to decrease can be readily identified. As a result, an electron beam lithography equipment can be operated efficiently.

Description

Detailed Description of the Invention] 3. Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention provides an exposure solution that is generated from design pattern data of an integrated circuit, etc. in a charged beam exposure apparatus. This invention relates to a data verification method in a charged beam camera for verifying power unit figures.

(Prior art) In recent years, LSI patterns have become increasingly fine and plate-like, and one device that can produce such patterns is a charged beam exposure device with one ζ2 For example, an electron beam exposure device is used. Here, an explanation will be given using this electron beam koji optical device as an example.

When exposing a desired pattern using the electron beam exposure apparatus, the graphic data generated by a design tool (for example, CAD) cannot normally be used in its original format as drawing data for the exposure apparatus.

The reason for this is that while design data is generally expressed in polygons, only trapezoidal or rectangular data is allowed for data used in electron beam exposure, and if there is overlap between shapes, multiple exposure may occur. This is due to the fact that it is not suitable as drawing data.

Therefore, the design data is subjected to, for example, contouring processing to remove multiple exposures, and then divided into basic figures such as rectangles and trapezoids or drawing unit figures to obtain figure data acceptable to the electron beam exposure apparatus.

In this case, in order to efficiently expose a desired pattern using an electron beam exposure device, it is essential to divide the figure so that the number of divided patterns is minimized, and generally the polygon shown in Figure 2) is Vertex P existing in the X direction as shown
A method of dividing figures based on l to P6 is known. Then, each figure is further divided into drawing unit figures which are unit figures for pattern creation, and drawing processing is performed based on the data.

However, in the shaped beam exposure method in which at least two beam shaping apertures are combined to generate a shaped beam through electro-optical overlapping, and the beam is used to perform drawing processing, the current density distribution may vary due to aberrations in the electron optical system. There is a uniformity, and this non-uniformity is particularly pronounced at the periphery of the beam. (Hereinafter, the above-mentioned non-uniformity will be referred to as "blur") When the figure shown in Figure 2 (b) is drawn due to the influence of this "blur", a figure C or smaller with the same degree of blur or less than the above-mentioned "blur" will be drawn. There is a drawback that strict and complicated control is required to draw figures such as 81, 82, and 83 shown in FIG. 2(c), which are referred to as .

In recent years, a figure division method that avoids the above problem has been proposed in Japanese Patent Application Laid-open No. 57.
Although it is disclosed in Japanese Patent No. 122525, it does not completely eliminate the above-mentioned minute figures in practical patterns.

As a means of verifying the presence or absence of the above-mentioned minute figures that occur in the above-mentioned situation, a human observes the LSI pattern obtained by drawing and evaluates the precision of the figure's dimensions, the "connection" parts between divided figures, etc. Then, we analyze the causes of the deterioration, and if necessary, output the drawing data of the desired area to an output device such as a printer or display for confirmation, or output the pattern figure to a graphic device based on the drawing data. This is an extremely primitive method in which the pattern is displayed as shown in Figure 3, and a human carefully observes the pattern and makes a 5 judgment on the minute figure, which poses a problem in improving the accuracy and efficiency of data verification.

In addition, as mentioned above, the problem will be solved in the future due to the rapid progress of LSI, which will lead to finer patterns and an increase in the number of L8I chip patterns. It becomes a big problem.

(Problems to which the invention is directed) The present invention was made to solve the above-mentioned problems in the conventional data verification method for charged beam exposure equipment, and its purpose is to improve data verification accuracy and efficiency. An object of the present invention is to provide a data verification method in a charged beam exposure apparatus that can perform data verification based on the data quality.

[Structure of the invention]

(Means for Solving the Problems) The gist of the present invention is to facilitate the processing of minute figures and other figures that require precise and complex control of the electron beam irradiation position and irradiation time due to the above-mentioned "blur" effect. The objective is to efficiently operate the device by displaying patterns in a format that can be identified.

That is, the present invention includes a mask having at least two beam-shaping apertures, and controls the electro-optical overlap of each aperture of these masks by a deflector to shape the size and shape of a charged beam. In a charged beam exposure device that exposes a desired pattern to a sample by irradiating it onto a sample, the LSI pattern is divided into a group of figures that can be single-irradiated with the charged beam, and the group of figures is graphically displayed by a figure display means. In this case, a figure including a short side shorter than the minimum length allowable for the charged beam is displayed in a different color from other figures or by hatching.

(Function) According to the present invention, it is possible to very easily identify minute figures generated when generating data used in an electron beam lithography device from LSI pattern data output from a design system such as CAD. This is effective in analyzing factors that reduce drawing accuracy, and can also improve pattern data verification accuracy. In addition, it becomes easy to verify the figure division method to prevent the occurrence of the above-mentioned minute figures,
The development time can be shortened, and as a result, the electron beam lithography system can be operated extremely efficiently.

(Example) The present invention will be described below with reference to 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 11ζ, and offset data 14 is sent to the sub deflector controller 15. Pattern data decoder 4
interprets the pattern 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, and generates a sub-deflector scanning control signal. A sub-deflection signal is generated, and the sub-deflector 17 determines the graphic drawing position in the sub-field.

FIG. 4 is a schematic diagram showing a process of generating drawing pattern data used when operating the above-mentioned electron beam drawing apparatus.

The LSI data designed with the CAD system is shown in Figure 5 (a
) as shown in polygon data A and B.

The LSI data is transferred to the host computer via a magnetic tape in order to convert the data format into a format that can be accepted by the electron beam lithography system. Then, in the host computer, in order to remove areas a1 and a2 that will be exposed multiple times by the electron beam, a polygonal shape is obtained by performing contouring processing as shown in FIG. In order to obtain the basic figure to be expressed, each vertex of the polygon is divided into figures in the Y direction (vertical direction on the paper) to generate cell data S1 to S7, and the data is sent to the electron beam lithography system to form a drawing unit figure. Based on this data, the electron beam lithography system is controlled by a control computer to perform the lithography process.

In order to verify whether the above basic figures are correctly generated in the above process, the above basic figures and the drawing unit figures obtained by dividing the basic figures into figures on the host computer are displayed on the graphic display as a pattern display device from the host computer. As shown in FIG. 6, graphics gl to g4 whose width and height are larger than the allowable length ε of the electron beam lithography device are displayed in a first color (for example, green);
Figures γ1 to r3 that include sides whose width and/or height are less than the above ε are colored in a second color (for example, red).
Or by displaying hatching such as filling out,
It was possible to very easily identify minute figures that would cause a decline in drawing accuracy.

As a result of the above, we were able to operate the electron beam lithography system extremely efficiently.

Note that the present invention is not limited to the embodiments described above. For example, the structure of the electron beam optical system is not limited to the embodiment and can be modified as appropriate. Furthermore, although this embodiment has been explained using an electron beam as an example, the beam is not limited to electron beams, and can be applied to charged beams including ion beams, and furthermore, an electrostatic plotter or a pen plotter can be used as a pattern display device. But that's fine. Further, the display on the pattern display device may be performed by a control computer, and various other modifications may be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, data verification can be performed efficiently with high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a device used in an embodiment of the present invention, Figs. 2 and 3 are diagrams for explaining conventional problems, and Fig. 4 generates drawing data related to the above device. FIG. 5 is a schematic diagram showing the process of generating a basic figure, and FIG. 6 is an explanatory diagram showing an example of a pattern display for verifying a drawing pattern. 1... Cell data, 2... Cell data buffer, 3
... Pattern data, 4... Pattern data decoder, 5... Variable beam forming can 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, internal driver, 13...Main deflector, 14
... Offset data, 15... Sub-deflector controller, 16... Sub-deflector driver, 17... Sub-deflector, 18... Cell size. Agent Patent Attorney Noriyuki Chika Yudo Kikuo Takehana Figure 8

Claims (3)

[Claims] (1) A mask having at least two beam shaping apertures is provided, the electron-optical overlap of each aperture of these masks is controlled by a deflector to shape the size and shape of the charged beam, and this shaped beam is applied to the sample. In a charged beam exposure device that exposes a desired pattern to the sample by irradiating the sample, L is applied to a group of figures that can be single-irradiated with the charged beam.
When the SI pattern is divided and the group of figures is graphically displayed by a graphic display means, the figure including a short side shorter than the minimum length allowable for the charged beam is displayed separately from other figures. Data verification method for charged beam exposure equipment. (2) In the data verification method according to claim 1, a figure including a short side shorter than a minimum length allowable for the charged beam is displayed in a different color from other figures. Data verification method for charged beam exposure equipment. (3) The data verification method according to claim 1, characterized in that a figure including a short side shorter than a minimum length allowable for the charged beam is displayed by hatching to distinguish it from other figures. Data verification method for charged beam exposure equipment.