JP4746928B2 - Drawing method, drawing apparatus, and electron beam acceleration voltage value acquisition method in electron beam drawing - Google Patents

Description

  The present invention relates to a drawing method, a drawing apparatus, and an electron beam acceleration voltage value acquisition method in electron beam drawing.

  In recent years, with the high integration of LSI, circuit line widths required for semiconductor devices have been reduced year by year. In order to form a desired circuit pattern on these semiconductor devices, an exposure area of a wafer in which dozens of original pattern patterns (also referred to as reticles or masks) on which a desired circuit pattern has been conventionally mounted is mounted on a stage. Then, a desired circuit pattern formed on the mask is transferred to the exposure area on the wafer by irradiating a laser beam or the like from the light source. For example, a reduction projection exposure apparatus is used. Such an original pattern is drawn on a glass substrate finished with high accuracy, and is formed through a resist process or the like. In general, a resist material is uniformly coated on a glass substrate having chromium (Cr) vapor-deposited on one side, and the resist material at a desired location is exposed using an energy beam using an electron beam or a laser as a light source. Let Then, after development, a pattern can be formed by etching Cr.

Here, the lithography technology responsible for the progress of miniaturization of semiconductor devices is an extremely important process for generating a pattern in a semiconductor manufacturing process. Conventionally, in the production of semiconductor devices, the light exposure technology has been used as described above. However, in recent years, the pattern dimensions of high-density integrated devices such as LSIs and VLSIs are approaching the limit resolution. Development of image exposure technology is an urgent task.
Electron beam (electron beam) exposure technology has inherently excellent resolution, and development of state-of-the-art devices such as DRAM (Dynamic random access memory) and production of some ASIC (application specific integrated circuit). Used for. Further, even when using a light exposure technique, it is used to form an original pattern for the production of advanced devices that are integrated with high density.

FIG. 11 is a conceptual diagram for explaining the operation of the variable shaping type electron beam exposure apparatus.
In the first aperture 410 in the variable shaping type electron beam exposure apparatus (variable shaping type EB (Electron beam) exposure apparatus), a rectangular opening 411 for molding the electron beam 330 is formed. Further, the second aperture 420 is formed with a variable shaping opening 421 for shaping the electron beam 330 that has passed through the opening 411 of the first aperture 410 into a desired rectangular shape. The electron beam 330 irradiated from the charged particle source 430 and passed through the opening 411 of the first aperture 410 is deflected by the deflector, passes through a part of the variable shaping opening 421 of the second aperture 420, and passes through a predetermined range. The sample is irradiated on a stage that moves continuously in one direction (for example, the X direction). That is, an exposure area of a sample 340 mounted on a stage in which a rectangular shape that can pass through both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is continuously moved in the X direction. Is shot and drawn. A method of creating an arbitrary shape by passing both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is referred to as a variable shaping method (see, for example, Patent Document 1).

In addition, regarding an electron beam exposure apparatus, there is a document describing a technique for changing an acceleration voltage of an electron beam according to a pattern area (see, for example, Patent Document 2).
JP 2000-58424 A JP-A-5-74692

  In the electron beam exposure method, when an electron beam is irradiated, the irradiation is accelerated. Then, the resist is exposed by allowing accelerated electrons to enter the resist on the sample. Here, the electrons incident on the resist collide with the atoms constituting the resist and are scattered multiple times, so that they travel not only in the electron incident direction but also in the lateral direction, and the lateral resist is also exposed. For this reason, the pattern dimensions are deteriorated. Thus, attempts have been made to increase the electron kinetic energy by increasing the acceleration voltage of the electron beam, to suppress the lateral spread of the electron, and to improve the beam resolution.

  On the other hand, when the acceleration voltage of the electron beam is increased, electrons enter deeper before exposing the resist in the incident direction, so the amount of energy stored in the resist in the incident direction is reduced and energy is stored to the required sensitivity. It takes time to do so and the throughput deteriorates. In other words, the acceleration voltage of the electron beam and the throughput are in a trade-off relationship.

  Conventionally, a method of determining the acceleration voltage of such an electron beam has not been established.

  An object of the present invention is to overcome such problems and provide a method for obtaining the best electron beam acceleration voltage.

The drawing method of one embodiment of the present invention includes:
In a drawing method for drawing a predetermined pattern by irradiating a sample with an electron beam,
An acceleration voltage value of an electron beam that is less than a predetermined beam blur value, an acceleration voltage value of an electron beam that is less than a predetermined error dimension value due to resist heating, and an acceleration voltage value of an electron beam that is more than a predetermined throughput value The electron beam is irradiated to the sample with an acceleration voltage value of the electron beam satisfying all of the above.

  As an electron beam acceleration voltage, an electron beam acceleration voltage value that is equal to or less than a predetermined beam blur value, an electron beam acceleration voltage value that is equal to or less than a predetermined error dimension value due to resist heating, and a predetermined throughput value or more. By adopting the acceleration voltage value of the electron beam that satisfies all of the acceleration voltage values of the electron beam, the acceleration voltage value of the electron beam, which has conventionally been groping, can be obtained under certain conditions desired by the user. Can do.

And the drawing apparatus of one mode of the present invention which uses such a drawing method,
An acceleration voltage value of an electron beam that is less than a predetermined beam blur value, an acceleration voltage value of an electron beam that is less than a predetermined error dimension value due to resist heating, and an acceleration voltage value of an electron beam that is more than a predetermined throughput value Among them, an input unit for inputting an acceleration voltage value of an electron beam satisfying all,
A drawing unit that draws a predetermined pattern on a sample by accelerating the electron beam at an acceleration voltage value of the input electron beam;
It is provided with.

  By drawing with the drawing apparatus having such a configuration, pattern drawing satisfying a certain condition desired by the user can be performed.

In addition, an electron beam acceleration voltage value acquisition method in electron beam writing according to an aspect of the present invention includes:
An input step of inputting an acceptable beam blur value and the acceptable error dimensional values and acceptable throughput value in the drawing device,
Using the first table that stores the relationship between the beam blur value, the electron beam acceleration voltage value, and the throughput value in the drawing apparatus, the electron beam acceleration voltage value and the throughput that are less than or equal to the allowable beam blur value. A first extraction step for extracting combinations with values;
Using a second table that stores the relationship between the error dimension value caused by resist heating, the acceleration voltage value of the electron beam, and the throughput value in the drawing apparatus, an electron beam that is equal to or less than the allowable error dimension value is stored. A second extraction step for extracting a combination of the acceleration voltage value and the throughput value;
In the drawing apparatus, a combination of an acceleration voltage value and a throughput value of an electron beam that is not more than the allowable beam blur value, and a combination of an acceleration voltage value and a throughput value of the electron beam that is not more than the allowable error dimension value A third extraction step of extracting a combination that is equal to or higher than the allowable throughput value from among the overlapping combinations;
An output step of outputting the combination extracted by the third extraction step;
It is provided with.

  With this configuration, it is possible to show the user a combination of the acceleration voltage value and the throughput value of the electron beam under a certain condition desired by the user.

In addition, a drawing apparatus according to another aspect of the present invention includes:
An input unit for inputting an acceptable beam blur value and the acceptable error dimensional values and acceptable throughput value,
A first storage unit for storing a first table showing a relationship among a beam blur value, an acceleration voltage value of an electron beam, and a throughput value;
A second storage unit that stores a second table indicating a relationship between an error dimension value caused by resist heating, an acceleration voltage value of the electron beam, and a throughput value;
Using the first and second tables, the combination of the acceleration voltage value of the electron beam and the throughput value which are not more than the allowable beam blur value input by the input unit, and the allowable error dimension value or less. A combination of the acceleration voltage value and the throughput value of the electron beam to be obtained, and a combination of the acceleration voltage value and the throughput value of the electron beam that is equal to or less than the extracted allowable beam blur value and the allowable error The allowable beam blur value is obtained by extracting a combination that is equal to or greater than the allowable throughput value from among the combinations of the acceleration voltage value and the throughput value of the electron beam that are equal to or smaller than the dimension value. follows it, becomes lower than the acceptable error dimensional values, Starring the acceleration voltage value of the electron beam becomes the allowable throughput value or more An arithmetic unit that,
A drawing unit that draws a predetermined pattern on a sample by accelerating the electron beam with the calculated acceleration voltage value of the electron beam;
It is provided with.

  With this configuration, it is possible to acquire the acceleration voltage value of the electron beam under a certain condition desired by the user in the drawing apparatus, and to draw with the acceleration voltage value of the electron beam.

The drawing apparatus according to the present invention further includes an output unit that outputs an acceleration voltage value of the electron beam calculated by the calculation unit,
In the input unit, the user is allowed to input an acceleration voltage value of a predetermined electron beam,
In the drawing unit, the electron beam is accelerated by an acceleration voltage value of the predetermined electron beam input by a user, and a predetermined pattern is drawn on the sample.

  By providing an output unit that outputs the acceleration voltage value of the electron beam calculated by the calculation unit, the user can select when there are a plurality of output acceleration voltage values of the electron beam.

  According to the present invention, the best electron beam acceleration voltage value can be obtained under conditions desired by the user. As a result, pattern drawing can be performed in accordance with conditions desired by the user.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram illustrating a main configuration of the drawing apparatus according to the first embodiment.
In FIG. 1, a variable shaping EB exposure apparatus 100 as an example of a drawing apparatus includes a drawing unit 150 and a control unit 160. The drawing unit 150 includes an electron column 102, an XY stage 105, an electron gun 201, an illumination lens 202, a first aperture 203, a projection lens 204, a deflector 205, a second aperture 206, an objective lens 207, a deflector 208, It has a Faraday cup 209. The control unit 160 includes a drawing data processing circuit 310 as an example of an arithmetic unit, a deflection control circuit 320, a digital / analog converter (DAC) 332, an electron optical system control circuit 342, an input unit 350, and a monitor as an example of an output unit. 360. A high voltage power supply 343 is disposed in the electron optical system control circuit 342. In FIG. 1, description of components other than those necessary for describing the first embodiment is omitted. Needless to say, the variable shaping EB exposure apparatus 100 usually includes other necessary configurations.

  The electron beam 200 accelerated and emitted from the electron gun 201 with a predetermined acceleration voltage illuminates the entire first aperture 203 having a rectangular hole, for example, a rectangular hole, by the illumination lens 202. Here, the electron beam 200 is first formed into a rectangle, for example, a rectangle. Then, the electron beam 200 of the first aperture image that has passed through the first aperture 203 is projected onto the second aperture 206 by the projection lens 204. The position of the first aperture image on the second aperture 206 is controlled by the deflector 205, and the beam shape and size can be changed. Then, the electron beam 200 of the second aperture image that has passed through the second aperture 206 is focused by the objective lens 207, deflected by the deflector 208, and XY stage disposed so as to be movable in the drawing chamber 103. The desired position of the sample 101 on 105 is irradiated. In such a case, the irradiated electron beam 200 is formed in a rectangular shape along the shape of the pattern with a shot size less than the set maximum shot size. The electron beam 200 is accelerated at a set acceleration voltage and is formed at a set current density J. The formed electron beam 200 is shot with a shot size less than the maximum shot size L for each shot. The desired electron beam 200 is shot on the sample 101 and a desired pattern is drawn.

  Here, in the drawing data processing circuit 310, for example, the acceleration voltage V of the electron beam, the current density J, the maximum shot size L, and the like are set. When the acceleration voltage V of the electron beam is set, the electron optical system control circuit 342 is notified. In the electron optical system control circuit 342, the high voltage power supply 343 is controlled to apply a predetermined voltage to the electron gun 201, and the electron beam jumps out of the electron gun 201 with the acceleration voltage V of the predetermined electron beam. When the maximum shot size L is set, the deflection control circuit 320 is notified. Then, the deflection control circuit 320 sets a voltage for controlling the deflector 205, and the DAC 332 applies the voltage applied to the deflector 205, so that the size of the shot figure shot on the sample 101 is the maximum shot. The electron beam 200 can be deflected so as to be shaped by the second aperture 206 with a shot size smaller than the size L. Further, when the current density J is set, the electron optical system control circuit 342 is notified. The electron optical system control circuit 342 can control the electron gun 201 to adjust the emission current and the filament temperature so that the current density J becomes a set value. Alternatively, and / or the electron optical system control circuit 342 can control the current density J to a set value by adjusting the aperture of the electron beam 200 in the illumination lens 202. Whether or not the current density is a predetermined value can be verified by irradiating the Faraday cup 209 with the electron beam 200.

  Input data to be set can be input from the input unit 350. As the input unit 350, for example, a means such as a keyboard or a mouse that is directly input manually by a user, a means that is input from a recording medium such as a flexible disk (FD), DVD, or compact disk (CD), or a local area network (LAN) ) Or any means for inputting through a network such as the Internet. In addition, the set value and the result processed by the drawing data processing circuit or the like are displayed on the monitor 360 which is an example of the output unit, and can be visually recognized by the user. The output unit is not limited to the monitor 360, and is output through a printer that prints on a paper medium, a unit that outputs to a recording medium such as a flexible disk (FD) or a compact disk (CD), or a network such as a local area network (LAN) or the Internet. Any of the means to do.

FIG. 2 is a diagram illustrating an example of the range of the best acceleration voltage.
In FIG. 2, the vertical axis shows the throughput, the horizontal axis shows the acceleration voltage, a line indicating the change in the throughput and acceleration voltage at the allowable beam blur value, the throughput and the acceleration voltage at the allowable error dimension value during resist heating. A line indicating a change in the value and a line indicating a throughput value at an allowable limit are shown. Then, the inventors have found that when the ranges of the areas on the permissible side are overlapped, there are areas surrounded by oblique lines that satisfy all the conditions.
Therefore, an acceleration voltage is selected from the area surrounded by the hatched lines, input from the input unit 350, and set in the drawing data processing circuit 310, so that the electron beam is irradiated with the selected acceleration voltage. Can do. Then, the drawing unit 150 draws a predetermined pattern on the sample by accelerating the electron beam with the acceleration voltage value of the electron beam. As a result, it is possible to perform pattern drawing on the sample 101 at a predetermined beam blur value or less, a predetermined error dimension value or less allowed by resist heating, and a predetermined throughput value or more.

FIG. 3 is a diagram illustrating an example of the relationship between the dose and the acceleration voltage.
FIG. 4 is a diagram illustrating an example of the relationship between sensitivity and acceleration voltage.
As shown in FIG. 3, the required dose increases as the acceleration voltage increases. If the required dose is large, the drawing time is increased accordingly. Therefore, as a result of this relationship, the drawing time increases as the acceleration voltage increases. That is, the throughput is degraded. On the other hand, as the required dose increases, the resist sensitivity deteriorates when the acceleration voltage increases as shown in FIG. In other words, the deterioration of resist sensitivity shown in FIG. 4 leads to the deterioration of throughput. From this relationship, when determining the use range shown in FIG. 2, it is also preferable to add a line indicating the change in the throughput and the acceleration voltage at the sensitivity (or the required dose) at the allowable limit. Then, an acceleration voltage is selected from the region surrounded by the oblique lines, input from the input unit 350, and set in the drawing data processing circuit 310, thereby irradiating the electron beam with the selected acceleration voltage. Can do.

FIG. 5 is a diagram illustrating an example of the relationship between the throughput and the acceleration voltage for each beam blur value.
FIG. 5 shows the relationship between the throughput and the acceleration voltage at each beam blur value when the beam blur value is set to six kinds of values B _{1 to} B _{6 in} order from the smallest value. When a predetermined throughput is defined, it can be seen that the beam blur value decreases as the acceleration voltage increases. That is, the beam resolution can be improved as the acceleration voltage is increased. Conversely, when a predetermined acceleration voltage is defined, it can be seen that the beam blur value increases as the throughput value increases. Here, in order to improve the throughput with the same acceleration voltage, it can be achieved by increasing the current density J. In order to increase the current density J, the opening angle α of the electron beam 200 can be increased. Assuming that the same electron gun 201 is used, the brightness β of the electron gun 201 is constant, and the relationship ββJ / α ² , so the current density J is increased by increasing the opening α. be able to. However, as the opening α increases, the aberration increases, and as a result, the beam resolution deteriorates. That is, as the throughput value is increased, the beam resolution is degraded. Therefore, an acceptable beam can be obtained by selecting a combination of a throughput value and an acceleration voltage value in a region where the beam blur value is equal to or lower than the allowable beam blur value (in FIG. 4, the region on the right side of the line at the allowable beam blur value). Resolution can be obtained.

FIG. 6 is a diagram illustrating an example of a pattern cross-sectional image drawn for each beam blur value.
In FIG. 6 (a), it shows an example of a pattern section image when the beam blur value is B _3. In the pattern cross-sectional image shown in FIG. 6A, the line pattern is drawn with high accuracy. FIG. 6B shows an example of a pattern cross-sectional image when the beam blur value is B ₄ , that is, when the value is larger than B ₃ . In the pattern cross-sectional image shown in FIG. 6 (b), the accuracy of the line pattern is drawn within an allowable range although the resolution is deteriorated compared with the pattern cross-sectional image shown in FIG. 6 (a). FIG. 6C shows an example of a pattern cross-sectional image when the beam blur value is B ₅ , that is, when the value is larger than B ₄ . In the pattern cross-sectional image shown in FIG. 6C, the resolution of the line pattern is further deteriorated as compared with the pattern cross-sectional image shown in FIG. 6B, and adjacent line patterns are adhered to each other. Because it is (short-circuited), it is drawn in an unacceptable range. Thus, in the example of FIG. 6, if the beam blur values and beam blur value of the allowable limit if the B _4, it is possible to perform the specified range of FIG.

FIG. 7 is a diagram illustrating an example of the relationship between the throughput and the acceleration voltage for each resist heating temperature.
In the electron beam exposure method, by making accelerated electrons enter the resist on the sample, the electrons incident on the resist collide with the atoms constituting the resist and the substrate and scatter multiple times. Part of it becomes heat energy, and eventually the resist is heated (heated). FIG. 7 shows an example of the relationship between the throughput and the acceleration voltage according to the temperature at which the resist is heated to rise (resist heating temperature).

FIG. 7 shows the relationship between the throughput and the acceleration voltage at each resist heating temperature when the resist heating temperature is set to ten values T _{1 to} T _{10 in} order from the lowest value. When a predetermined throughput is defined, it can be seen that the higher the acceleration voltage, the higher the resist heating temperature. Even when a predetermined acceleration voltage is specified, it can be seen that the higher the throughput value, the higher the resist heating temperature.

FIG. 8 is a diagram illustrating an example of the relationship between the throughput and the acceleration voltage for each error size due to resist heating.
FIG. 8 shows the relationship between the throughput and the acceleration voltage in each error dimension value when the error dimension value caused by resist heating is set to ₁₀ values of δ ₁ to δ _{10 in} order from the smallest value. Since the dimensional error is caused by the temperature of the resist being heated to increase, it corresponds to the resist heating temperature. Therefore, when a predetermined throughput is defined, it can be seen that the error dimension value increases as the acceleration voltage is increased. Even when a predetermined acceleration voltage is defined, it can be seen that the error dimension value increases as the throughput value increases. Therefore, by selecting a combination of a throughput value and an acceleration voltage value in a region that is less than or equal to the tolerance limit error dimension value (the region on the left side of the tolerance limit error dimension value in FIG. 7), an allowable dimension is selected. Accuracy can be obtained.

  Finally, by narrowing down to an area where the throughput value exceeds the allowable limit, a combined area of the throughput value and acceleration voltage value at an acceptable throughput can be obtained with an acceptable beam resolution and an acceptable dimensional accuracy. .

  As described above, an acceleration voltage value is selected from the combined region of the throughput value and the acceleration voltage value at an acceptable throughput with an acceptable beam blur value, an acceptable error dimension value, and input to the input unit 350. By doing so, it is possible to perform pattern writing with an acceptable throughput with an acceptable beam resolution and an acceptable dimensional accuracy.

Embodiment 2. FIG.
In the first embodiment, an acceleration voltage value that results in satisfying a desired condition is extracted or obtained outside the drawing apparatus. However, the acceleration voltage value may be extracted or obtained inside the drawing apparatus. It is.

FIG. 9 is a block diagram showing a main part of the configuration in the second embodiment.
9, the drawing data processing circuit 310 includes an arithmetic circuit 502, a beam blur table 504, an error dimension table 506, a storage device 508, a graphic processing circuit 510, and a setting circuit 512. The beam blur table 504 stores, for example, the correspondence between the throughput and the acceleration voltage for each beam blur value shown in FIG. The correspondence relationship is not limited to each beam blur value, and may correspond to each throughput or each acceleration voltage. In other words, the relationship between the beam blur value, the acceleration voltage value of the electron beam 200, and the throughput value is stored. In the error dimension table 506, for example, the correspondence relationship between the throughput and the acceleration voltage is stored for each error dimension value shown in FIG. The correspondence relationship is not limited to each error dimension value, and may be by throughput or by acceleration voltage. In other words, the relationship between the error dimension value caused by resist heating, the acceleration voltage value of the electron beam, and the throughput value is stored. In the second embodiment, other configurations are the same as those in FIG.

FIG. 10 is a flowchart showing the main part of the drawing method according to the second embodiment.
In S (step) 902, as an input process, the input unit 350 inputs a predetermined beam blur value, a predetermined error dimension value, and a predetermined throughput value. Here, the user inputs an allowable predetermined beam blur value, a predetermined error dimension value, and a predetermined throughput value.

  In S904, as a first extraction step, the arithmetic circuit 502 uses the beam blur table 504 to calculate the acceleration voltage value and the throughput value of the electron beam 200 that are equal to or lower than the predetermined beam blur value input by the input unit 350. Extract combinations. By extracting a combination of an acceleration voltage value and a throughput value of an electron beam that is equal to or less than a predetermined beam blur value, a combination of an acceleration voltage value and a throughput value that achieves an acceptable beam resolution can be obtained.

  In S906, as a second extraction step, the arithmetic circuit 502 uses the error dimension table 506 to calculate the acceleration voltage value and the throughput value of the electron beam 200 that are equal to or less than the predetermined error dimension value input by the input unit 350. Extract combinations. By extracting the combination of the acceleration voltage value and the throughput value of the electron beam that is equal to or less than the predetermined error dimension value, the acceleration voltage value and the throughput value that allow the dimension accuracy even if an error occurs due to resist heating, Can be obtained.

  In step S908, as a third extraction step, the arithmetic circuit 502 causes the combination of the acceleration voltage value and the throughput value of the electron beam 200 that are equal to or less than the extracted predetermined beam blur value and the electrons that are equal to or less than the predetermined error dimension value. Among the combinations of the acceleration voltage value and the throughput value of the beam 200, a combination that is equal to or greater than the predetermined throughput value input by the input unit 350 is extracted from among the overlapping combinations. By such extraction, it is possible to obtain a combination of a throughput value and an acceleration voltage value with an acceptable throughput with an acceptable beam resolution and an acceptable dimensional accuracy.

  In S910, as an output process, the monitor 360 outputs the combination extracted in the third extraction process by displaying it on the screen. In the case of outputting to such a monitor 360, it is preferable that the graphic processing circuit 510 processes the graph as shown in FIG. Through this process, the user can obtain the optimum acceleration voltage value of the electron beam 200 in electron beam writing.

  In S912, as an acceleration voltage input process, the user inputs an acceleration voltage value of a predetermined electron beam from the input unit 350 from a combination of a throughput value and an acceleration voltage value in accordance with the user drawing conditions displayed on the monitor 360. input. When displayed as a graph on the monitor 360, an acceleration voltage value located in the region as shown in FIG. 2 may be selected. Further, when displayed as a table or list on the monitor 360, an acceleration voltage value may be selected from the table or list.

  In S914, as an acceleration voltage setting step, the setting circuit 512 sets the input acceleration voltage value as an acceleration voltage value for drawing. When the acceleration voltage V of the electron beam is set, the electron optical system control circuit 342 is notified. In the electron optical system control circuit 342, control is performed so that a predetermined voltage is applied to the electron gun 201 from the high voltage power source 343. When drawing, the electron beam jumps out of the electron gun 201 with the acceleration voltage V of the predetermined electron beam. .

  In S916, as a drawing process, the drawing unit 150 draws a predetermined pattern on the sample 101 by accelerating the electron beam 200 with the acceleration voltage value V of the electron beam input by the user.

  In the above description, the acceleration voltage value is input again by the user who has seen the monitor 360. However, the setting circuit 512 may automatically select the acceleration voltage value from the range of the extracted acceleration voltage values. Such automatic selection may be selected at random from the range of extracted acceleration voltage values. Alternatively, among the predetermined beam blur value, the predetermined error dimension value, and the predetermined throughput value, a particularly important item is set, and an acceleration voltage value at a position where the important item is the best is automatically selected. Also good. For example, in the example of FIG. 2, when increasing the throughput is an important item, an acceleration voltage value corresponding to the upper vertex of the triangle may be automatically selected from the use range. When an important item is to reduce the beam blur value, that is, to increase the beam resolution, an acceleration voltage value corresponding to the right corner of the base of the triangle may be automatically selected. When minimizing the error dimension due to resist heating is an important item, an acceleration voltage value corresponding to the left corner of the base of the triangle may be automatically selected from the use range.

  In the second embodiment, the acceleration voltage value that meets the conditions is extracted from each table. However, the arithmetic circuit 502 calculates a predetermined expression to calculate a predetermined beam blur value input by the input unit. The accelerating voltage value of the electron beam may be obtained as follows, which is not more than a predetermined error dimension value and is not less than a predetermined throughput value. In other words, any extraction means that can extract an acceleration voltage value in accordance with a predetermined condition, either a table or an expression, may be used.

  Furthermore, after the user sees the table, list or graph displayed on the monitor 360, the beam blur value, error dimension value, or throughput value, which is the initially input condition, is changed, and acceleration that meets the condition is again performed. A voltage value may be obtained. Alternatively, the user can change the acceleration voltage according to his / her convenience and select the operation condition (drawing condition) of the apparatus giving priority to throughput or accuracy by changing the beam blur value, error dimension value, or throughput value. May be.

  In the above description, what is described as “˜circuit” may be constituted by a program operable by a computer. Or you may make it implement by not only the program used as software but the combination of hardware and software. Alternatively, a combination with firmware may be used. When configured by a program, the program is recorded on a recording medium such as a magnetic disk device, a magnetic tape device, an FD, or a ROM (Read Only Memory). The input data and output data described in the operation of “˜circuit” are stored in a storage device 508 such as a register or a memory. Each calculation may be performed using an adder or a multiplier.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. For example, the description of the control unit configuration for controlling the variable shaping EB exposure apparatus 100 is omitted, but it goes without saying that the required control unit configuration is appropriately selected and used.

  In addition, all drawing methods, drawing apparatuses, and electron beam accelerating voltage value obtaining methods in electron beam drawing that include elements of the present invention and can be appropriately modified by those skilled in the art are included in the scope of the present invention.

1 is a conceptual diagram illustrating a main configuration of a drawing apparatus according to Embodiment 1. FIG. It is a figure which shows an example of the range of the best acceleration voltage. It is a figure which shows an example of the relationship between a dose amount and an acceleration voltage. It is a figure which shows an example of the relationship between a sensitivity and an acceleration voltage. It is a figure which shows an example of the relationship between the throughput according to beam blur value, and an acceleration voltage. It is a figure which shows an example of the pattern cross-sectional image drawn by beam blur value. It is a figure which shows an example of the relationship between the throughput according to resist heating temperature, and an acceleration voltage. It is a figure which shows an example of the relationship between the throughput according to the error dimension by resist heating, and an acceleration voltage. 10 is a block diagram illustrating a main part of a configuration in a second embodiment. FIG. FIG. 10 is a flowchart showing a main part of a drawing method process according to the second embodiment. It is a conceptual diagram for demonstrating operation | movement of a variable shaping type | mold electron beam exposure apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Variable shaping type EB exposure apparatus 101,340 Sample 102 Electron barrel 105 XY stage 150 Drawing part 160 Control part 200 Electron beam 201 Electron gun 202 Illumination lens 203,410 First aperture 206,420 Second aperture 204 Projection lens 205, 208 Deflector 207 Objective lens 209 Faraday cup 411 Opening 421 Variable shaping opening 310 Drawing data processing circuit 320 Deflection control circuit 330 Electron beam 332 DAC
342 Electro-optic system control circuit 343 High voltage power supply 350 Input unit 360 Monitor 422 Partial batch mask 430 Charged particle source 502 Operation circuit 504 Beam blur table 506 Error dimension table 508 Storage device 510 Graphic processing circuit 512 Setting circuit

Claims (3)

An input step of inputting an acceptable beam blur value and the acceptable error dimensional values and acceptable throughput value in the drawing device,
Using the first table storing the relationship between the beam blur value, the acceleration voltage value of the electron beam, and the throughput value in the drawing apparatus, the acceleration voltage value of the electron beam that is equal to or less than the allowable beam blur value A first extraction step for extracting a combination with a throughput value;
An electron beam that is less than or equal to the allowable error dimension value by using a second table that stores the relationship between the error dimension value caused by resist heating, the acceleration voltage value of the electron beam, and the throughput value in the drawing apparatus. A second extraction step of extracting a combination of the acceleration voltage value and the throughput value of
In the drawing apparatus, a combination of an acceleration voltage value and a throughput value of an electron beam that is not more than the allowable beam blur value, and an acceleration voltage value and a throughput value of the electron beam that are not more than the allowable error dimension value A third extraction step of extracting a combination that is equal to or greater than the allowable throughput value from among the combinations that are duplicated;
An output step of outputting the combination extracted by the third extraction step in the drawing device ;
An accelerating voltage value acquisition method for electron beams in electron beam lithography. An input unit for inputting an acceptable beam blur value and the acceptable error dimensional values and acceptable throughput value,
A first storage unit for storing a first table showing a relationship among a beam blur value, an acceleration voltage value of an electron beam, and a throughput value;
A second storage unit that stores a second table indicating a relationship between an error dimension value caused by resist heating, an acceleration voltage value of the electron beam, and a throughput value;
Using the first and second tables, the combination of the acceleration voltage value of the electron beam and the throughput value which are not more than the allowable beam blur value input by the input unit, and the allowable error dimension value or less. A combination of the acceleration voltage value and the throughput value of the electron beam to be obtained, and a combination of the acceleration voltage value and the throughput value of the electron beam that is equal to or less than the extracted allowable beam blur value and the allowable error The allowable beam blur value is obtained by extracting a combination that is equal to or greater than the allowable throughput value from among the combinations of the acceleration voltage value and the throughput value of the electron beam that are equal to or smaller than the dimension value. follows it, becomes lower than the acceptable error dimensional values, Starring the acceleration voltage value of the electron beam becomes the allowable throughput value or more An arithmetic unit that,
A drawing unit for drawing a pattern on the sample at an accelerating voltage value of the computed the electron beam to accelerate the electron beam,
A drawing apparatus comprising: The drawing apparatus further includes an output unit that outputs an acceleration voltage value of the electron beam calculated by the calculation unit,
In the input unit, the user inputs one selected from the acceleration voltage value of the output electron beam ,
3. The drawing apparatus according to claim 2 , wherein the drawing unit draws a predetermined pattern on the sample by accelerating the electron beam with an acceleration voltage value of the predetermined electron beam input by a user.

Images