JP3938149B2 - Electron beam drawing apparatus, electron beam drawing system, and drawing method - Google Patents

Description

  The present invention relates to an electron beam drawing apparatus, an electron beam drawing system, and a drawing method for drawing a desired pattern by irradiating a sample with an electron beam.

  FIG. 10 shows a functional block diagram of a drawing data generation unit in the case of a conventional electron beam drawing apparatus. In the conventional electron beam drawing apparatus, the drawing data (coordinates, dimensions, and irradiation amount) of the irradiation unit generated by the electron beam drawing data generating unit 13 is corrected by the predetermined electron beam correcting unit 14, and the corrected drawing data is corrected. The electron beam designated by (1) is irradiated to the photosensitive agent coated on the sample by the electron beam drawing means 16.

  There are various types of electron beam correction by the electron beam correcting means 14, but here, proximity effect correction is targeted. The proximity effect means that the electron beam irradiated on the sample passes through the surface of the photosensitive agent layer, and the electron beam backscattered inside the sample passes again through the photosensitive agent on the sample surface. This is a phenomenon in which overexposure occurs at high portions. Therefore, in an electron beam drawing apparatus, Japanese Patent Application Laid-Open No. 3-225816 discloses an exposure map based on the exposure area density of a pattern drawn on a sample by performing empty drawing without irradiating an electron beam before actual drawing. In an actual drawing, while referring to the contents of the memory by the exposure amount map creating means 15 shown in FIG. 10, the irradiation amount of the electron beam becomes relatively small at a place where the exposure area density is high, A technique has been disclosed in which correction is performed so that the amount of electron beam irradiation is relatively large at a place where the exposure area density is low.

JP-A-3-225816

  In the prior art, in order to perform optimal drawing, conditions such as the mesh size for dividing the drawing pattern and the number of times of smoothing are changed, an exposure amount map is created each time, and an empty drawing operation is performed accordingly. Is evaluating. Therefore, in order to optimally draw one pattern of drawing data, a plurality of exposure amount map creations and empty drawing operations are required. Furthermore, in the conventional technique, since the exposure amount map is recreated every time the condition changes, the exposure amount map before the recreation cannot be retained. Therefore, in order to perform optimum drawing again, the same drawing data must be created again. These reduce the throughput of the electron beam drawing apparatus. In particular, the mask electron beam drawing apparatus has a problem in that throughput can be reduced because only one mask can be drawn for one piece of drawing data, and one piece of drawing data cannot be used repeatedly.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an electron beam drawing apparatus, an electron beam drawing system, and a drawing method capable of improving the throughput.

  In order to solve the above-described object, the present invention provides drawing data generating means for generating drawing data for forming a drawing pattern on a sample, exposure dose map generating means for generating an exposure map of an electron beam from the drawing data, A plurality of drawing data generation units comprising electron beam correction means for correcting the irradiation amount of the electron beam applied to the sample with reference to the exposure amount map, and the electron based on the value corrected by the electron beam correction means And electron beam drawing means for drawing by irradiating the sample with a line.

  By providing a plurality of drawing data generation units and making it possible to create a plurality of exposure amount maps of different conditions and types in parallel, it is possible to quickly evaluate the optimum drawing conditions and achieve the object. be able to. Examples of drawing data generation conditions include the mesh size when creating an exposure map, the number of times of area density smoothing performed between adjacent meshes, and the like.

  Further, the electron beam drawing apparatus provided with the output comparing means for comparing the outputs from the plurality of drawing data generating means makes the entire control circuit compare the outputs by causing the drawing data generating sections to perform the same operation. Can be checked, and the reliability of the electron beam drawing apparatus can be increased.

  Furthermore, the electron beam drawing apparatus has a function of performing exposure amount map creation of the second drawing data in parallel while drawing the first drawing data. Further, the electron beam drawing apparatus has a function of dividing and forming an exposure amount map to be drawn by the plurality of drawing data generation units. With these functions, even for large drawing patterns that exceed the range where the exposure amount map to be drawn can be generated by one drawing data generation unit, the creation of the exposure amount map is shared by a plurality of drawing data generation units. Therefore, a decrease in throughput can be prevented.

  Further, the second electron beam drawing device is connected by connecting the two electron beam drawing devices with a data transmission means, and the drawing data generated by the first electron beam drawing device is transferred to the second electron beam drawing device. The drawing apparatus can draw the same drawing data as the first electron beam drawing apparatus.

  Further, if the electron beam drawing apparatus according to the present invention is used for pattern drawing on a mask, reticle, etc. used in an exposure apparatus, drawing is performed by repeatedly using drawing data once created, so that throughput can be improved. .

  As described above, according to the present invention, an electron beam drawing apparatus, an electron beam drawing system, and a drawing method capable of improving the throughput can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

First, a configuration of an example of an electron beam drawing apparatus according to the present invention will be described with reference to a cross-sectional view shown in FIG. In FIG. 1, the section shown on the right side in cross section is an electron beam mirror 100 that actually draws a wafer, and the surrounding square represents the function of controlling the electron beam mirror 100 as a block. The sample 108 is transferred from the transfer unit 102 to the sample stage 101 inside the electron beam mirror 100. The electron beam 104 emitted from the electron gun 103 at the top of the electron beam mirror 100 is shaped by a lens 106 in the lens body and further deflected by a deflector 107 including an electromagnetic deflector and an electrostatic deflector. The target position of the sample 108 placed on the sample stage 101 is irradiated. Several cross-sectional shapes of the irradiated electron beam 104 can be transferred onto the sample 108 by selecting the aperture 105.

  The left part of FIG. 1 represents a system control function as a block, and shares control of the entire system and an external interface. The drawing data of the pattern to be drawn held in the hard disk 121 is transmitted to the computer 112. A block group surrounded by a frame 111 is a control system digital processing group that converts drawing data transmitted from the computer 112 into electron beam deflection data continuously, in a pipeline manner, and at high speed. Are connected to each other via a bus 119, and each processing unit shown in the figure performs the following processing.

(1) Graphic data portion 123
The compressed drawing data transmitted from the computer 112 is stored.

(2) Figure restoration unit 124
Restore the compressed drawing data to graphic data.

(3) Graphic decomposition unit 125
Each restored figure is replaced with a shot having a shape that can be drawn with an electron beam, and data on the position, shape, and exposure amount of each shot is created.

(4) Alignment correction unit 126
A position shift or deformation between the electron beam irradiation position and the sample 108 is monitored by the sensor 109, and correction is performed in accordance with the shift or deformation.

(5) Proximity effect correction unit 127
Processing for correcting the proximity effect is performed. An exposure amount map 129 which is an area map per unit area of a pattern to be drawn in advance is obtained and stored in the memory, and a process of correcting the exposure amount in shot units while referring to the value is performed.

(6) Tracking absolute calibration unit 128
In order to enable continuous drawing, the target position on the sample 108 is irradiated with the electron beam 104 based on the position of the sample table 101 measured by the length measuring device 110 and the sample table position measuring unit 120. The electron beam deflection position is calculated, and the deflection distortion amount of the electron beam mirror 100 is also corrected.

(7) Procedure control unit 122
It is in charge of monitoring and control so that the processing of each unit moves smoothly.

The data from the units in the frame 111 is D / A converted by the D / A converter 113 and transferred to the beam control unit 114 to control the lens 106 and the deflector 107. In addition, the high voltage power source 115 generates an acceleration voltage of the electron gun 103, the aperture control unit 116 controls the aperture exchanging unit 131 to select the shape of the aperture 105, and the sample stage control unit 117 moves the sample stage 101. The transport system control unit 118 controls the transport unit 102 that transports the sample 108 to the sample stage 101. Each unit is connected by a bus 119, and signals are transferred through the interface. These units can also be controlled by the computer 112.

  2 to 7 show a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating functions of the proximity effect correction unit 127 illustrated in FIG. This electron beam drawing apparatus includes a plurality of drawing data generation units 12 a, 12 b,..., 12 n controlled by the drawing data generation unit control unit 11 and one electron beam drawing unit 16. Each of the drawing data generation units 12a, 12b,..., 12n has drawing data generation means 13a, 13b,.
13n, electron beam correcting means 14a, 14b,..., 14n and exposure amount map creating means 15a, 15b,. The drawing data generation unit control means 11 issues an instruction such as drawing data conditions to the plurality of drawing data generation units 12a, 12b,..., 12n, and data electron beams from the drawing data generation units 12a, 12b,. An instruction to select data to be output to the drawing means 16 is issued.

  FIG. 3 is a flowchart showing a procedure for creating an exposure amount map, and FIG. 4 shows an example of a pattern shape. In step S41 of FIG. 3, the pattern 51 is divided by the mesh size 52 as shown in FIG. 4, and the pattern area density in each mesh is obtained in step S42. Next, in step S43, smoothing is performed to reduce a dimensional change in a portion where the area density greatly changes between adjacent meshes, and an exposure amount map is created in step S44. When the exposure map is created, electron beam data (for example, coordinates, dimensions, and dose) from the drawing data creation unit 13 is sent to the exposure map creation unit 15.

  FIG. 5 is a block diagram showing the exposure amount map creating means 15 in more detail. In the exposure amount map creating means 15, in order to create an exposure amount map on the exposure amount map memory 61 from the drawing data generated by the drawing data generating means 13 shown in FIG. 2, a corresponding memory address is generated from the coordinate data. A coordinate-address converting means 62 for performing the processing and an area density calculating means 63 for generating an area density from the data indicating the dimension of the pattern. The area density smoothing means 64 smoothes the value generated thereby. The obtained values are stored in the exposure amount map memory 61 while being accumulated. When the value stored in the exposure map memory 61 is smoothed again, the value is read from the exposure map memory 61, smoothed by the area density smoothing means 64, and stored in the exposure map memory 61.

  At the time of drawing, the electron beam correcting unit 14 corrects the irradiation amount data among the drawing data input from the drawing data generating unit 13 with the corresponding address value of the previously generated exposure amount map. That is, the value corresponding to the drawing data and several surrounding values are read from the value of the exposure amount map memory 61 created by the exposure amount map creating means 15, and the density of the surroundings of the drawing data is calculated from them. The dose is adjusted so that it is inversely proportional to it. The electron beam drawing means 16 outputs the irradiation amount and coordinates corrected by the electron beam correction means 14 and the size of the electron beam to an electron gun to perform correction drawing.

  Next, in FIG. 2, the drawing data generation unit control means 11 issues an instruction for conditions such as the divided mesh size and the number of smoothing that are different for each drawing data generation unit 12 a, 12 b,. Each of the drawing data generation units 12a, 12b,..., 12n is based on the drawing data generated by the respective drawing data generation means 13a, 13b,. The area density is calculated for each mesh size by the area density calculation means 63 shown in FIG. 5, and the calculated value is associated with the memory address output from the coordinate-address conversion means 62 in the exposure amount map memory 61. Store. In this way, a plurality of exposure dose maps with different conditions can be created in the same time as the conventional exposure dose map creation time.

  Next, the drawing data generation unit control unit 11 selects one of the drawing data generation units 12a, 12b,..., 12n, and drawing data is supplied from the drawing data generation unit 13 by the selected drawing data generation unit 12n. When output, the corresponding address in the exposure map memory 61 shown in FIG. 5 is output from the coordinate-address conversion means 62 as in the previous exposure map generation, and the corresponding value and its neighboring value are read out. It is. The electron beam correction unit 14 refers to the read value and corrects the irradiation amount so that the irradiation amount is relatively small at a high exposure density and relatively large at a low exposure density. The electron beam drawing means 16 receives the drawing data corrected by the electron beam correction means 14 and executes correction drawing. This operation is continuously performed on the drawing data of all the drawing data generation units 12a, 12b,..., 12n, the drawing result is evaluated, and the drawing operation is performed again based on the drawing data that is optimized as a result of the evaluation. Is possible.

  FIG. 6 is a time chart showing the amount of exposure map creation time and drawing time, and compares the case of the prior art and the case of the first embodiment of the present invention.

  In FIG. 6, the drawing data under three different conditions are evaluated, and the time ratios when drawing with the data of the optimum evaluation result (drawing data under condition 2 in FIG. 6) are compared again. . In the case of the conventional technique, an exposure amount map is created under condition 1, empty drawing is performed based on the exposure amount map, and then an exposure amount map is created under condition 2 and empty drawing is performed. Thereafter, an exposure map is created under condition 3 and empty drawing is performed. Then, the result of empty drawing under each condition is evaluated, and if it is found that condition 2 is optimal, an exposure map is created again under condition 2 and actual drawing is performed.

  On the other hand, in the first embodiment of the present invention, exposure amount maps with different conditions are created simultaneously. That is, the exposure amount map of condition 1 is created in parallel by the drawing data generation unit 12a, the exposure amount map of condition 2 is created by the drawing data generation unit 12b, and the exposure amount map of condition 3 is created in parallel by the drawing data generation unit 12c. The The created exposure amount map is held in each drawing data generation unit. The electron beam drawing means 16 sequentially draws under the conditions 1, 2 and 3 based on the exposure amount map held in each of the drawing data generation units 12a, 12b and 12c. As a result of evaluating the drawing result, if it is found that the condition 2 is optimal, drawing under the condition 2 can be immediately started using the exposure amount map held in the drawing data generation unit 12b. In this way, the drawing throughput can be greatly improved as compared with the prior art.

  FIG. 7 is a time chart of another example of the passage of time shown in FIG. In this example, the plurality of drawing data generation units 12a, 12b,..., 12n shown in FIG.

  The drawing data generation unit control unit 11 shown in FIG. 2 generates different drawing data in each of the five drawing data generation units 12a, 12b, 12c, 12d, and 12e in FIG. Give instructions to do. The five drawing data generation units 12a, 12b, 12c, 12d, and 12e create an exposure amount map based on the drawing data output from the respective drawing data generation means 13. As a result, as shown in the figure, in the prior art, the drawing time of the six patterns A, B, C, D, E, and F is the same as the time spent drawing the two patterns A and B. Is possible. Further, during the correction drawing of the patterns A to F, the drawing data generation units 12b to 12e can create an exposure amount map from the pattern G to J, so that after the completion of the correction drawing of the pattern F, the pattern G Correction drawing is possible.

  As described above, it is possible to create a plurality of exposure amount maps of different types in the same time as the creation time of one exposure amount map in the prior art. Then, the next electron beam drawing can be continuously performed with different drawing data for each exposure amount map. In addition, during the electron beam drawing, a drawing data generation unit that is not in use can create an exposure amount map of new drawing data in parallel, thereby greatly improving throughput.

Further, in the electron beam drawing apparatus shown in FIG. 2, an exposure amount map exceeding the range that can be generated by one drawing data generation unit can be easily generated. That is, when the exposure amount map to be drawn exceeds the range that can be generated by one drawing data generation unit, the entire exposure map is divided into exposure map units that can be processed by one drawing data generation unit. Create an exposure map. First, the drawing data generation unit controller 11 instructs how to divide the entire exposure amount map, and the drawing data generation units 12a, 12b,. Next, the electron beam drawing unit 16 performs drawing with reference to the exposure amount map generated by the drawing data generation unit 12a, and the electron beam drawing unit 16 continues with reference to the exposure amount map generated by the drawing data generation unit 12b. When each drawing data generation unit 12n is controlled by the drawing data generation unit control means 11 so that the drawing is performed in the above manner, it is possible to draw an exposure amount map of any size.

  FIG. 8 shows a second embodiment according to the present invention and is a block diagram corresponding to FIG. The present embodiment is characterized in that it includes two drawing data generation units 12a and 12b and an output comparison means 81. The output comparison unit 81 compares the output of the electron beam correction unit 14a of the drawing data generation unit 12a with the output of the electron beam correction unit 14b of the drawing data generation unit 12b.

In FIG. 8, first, the drawing data generation unit control unit 11 causes the drawing data generation unit 12 a and the drawing data generation unit 12 b to perform the same operation, and the output comparison unit 81 compares the outputs from both. When the output of the electron beam correction unit 14a and the output of the electron beam correction unit 14b do not match, the information is transmitted to the drawing data generation unit control unit 11, and the drawing data generation unit control unit 11 again outputs each drawing data. The generation units 12 a and 12 b are instructed to start up, and the output comparison unit 81 compares both outputs. If the output comparison results in a match, the result is normal, and by performing the drawing operation, drawing defects can be prevented in advance, and the reliability of the apparatus and system can be greatly improved.

  FIG. 9 shows a third embodiment of the present invention and is a block diagram corresponding to FIG. In the present embodiment, a first electron beam drawing apparatus 91 having the same configuration as that shown in FIG. 8 and a second electron beam in which only the electron beam drawing means 16a is mounted on the configuration shown in FIG. A drawing device 92a and an electron beam drawing device 92n equipped with only the electron beam drawing means 16n are combined through a communication means 93. In the first electron beam drawing apparatus 91, if the result of the output comparison unit 81 is normal, the data storage unit 94 holds the output of the drawing data generation unit 12a or the drawing data generation unit 12b.

In the electron beam drawing apparatus 91, the drawing data generation unit control unit 11 causes the two systems of the drawing data generation unit 12 a and the drawing data generation unit 12 b to perform the same operation, and the output comparison unit 81 compares both outputs. If the result of the output comparison unit 81 is normal, the drawing data generation unit control unit 11 issues a drawing work instruction to the drawing data generation unit 12a based on the information, and the drawing data generation unit 12b. The data storage means 94 is instructed to transmit the output. The data storage means 94 holds the output of the electron beam drawing data generation unit 12b. The retained data is transferred to the second electron beam drawing apparatus 92a to the electron beam drawing apparatus 92n via the communication means 93, so that the plurality of electron beam drawing apparatuses are the same as the first electron beam drawing apparatus. Drawing is possible.

  As described above, according to the present invention, the optimum drawing data can be evaluated quickly, and the throughput is improved. Further, the exposure map data can be held, and the work of creating the same data when drawing again can be omitted, so that the throughput can be further improved. In addition, the reliability of the apparatus and system can be improved.

Sectional drawing which shows the example of the electron beam drawing apparatus by this invention. The block diagram which shows the function of the proximity effect correction | amendment part shown in FIG. The flowchart which shows the procedure of exposure amount map preparation. Explanatory drawing which shows the example of the shape of a pattern. The block diagram which shows the exposure amount map preparation means in detail. The time chart which shows the magnitude | size of exposure amount map creation time and drawing time. The time chart which shows the magnitude | size of exposure amount map creation time and drawing time. The block diagram which shows the function of the proximity effect correction | amendment part shown in FIG. The block diagram which shows the function of the proximity effect correction | amendment part shown in FIG. The block diagram which shows the function of the electron beam drawing apparatus of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Drawing data generation part control means, 12a, 12b, ..., 12n ... Drawing data generation part, 13a, 13b, ..., 13n ... Drawing data generation means, 14a, 14b, ..., 14n ... Electron beam correction means, 15a, 15b,..., 15n ... exposure amount map creation means, 16, 16a, 16n ... electron beam drawing means, 51 ... pattern, 52 ... mesh size, 61 ... exposure amount map memory, 62 ... coordinate-address conversion means, 63 ... area Density calculation means, 64 ... area density smoothing means, 81 ... output comparison means, 91 ... first electron beam drawing apparatus, 92a ... second electron beam drawing apparatus, 92n ... electron beam drawing apparatus, 93 ... communication means, 94 ... Data storage means, 100 ... Electron beam mirror, 101 ... Sample stage, 102 ... Transport section, 103 ... Electron gun, 104 ... Electron beam, 105 ... Aperture, 106 ... Lens, 107 Deflector, 108 ... sample, 109 ... sensor, 110 ... measuring machine, 111 ... frame, 112 ... machine, 113 ... D / A converter, 114 ... beam control unit,
DESCRIPTION OF SYMBOLS 115 ... High voltage power source, 116 ... Aperture control part, 117 ... Sample stand control part, 118 ... Conveyance system control part, 119 ... Bus, 120 ... Sample stand position measuring part, 121 ... Hard disk, 122 ... Procedure control part, 123 ... Graphic data section 124... Graphic restoration section 125. Graphic decomposition section 126 126 Alignment correction section 127 127 Proximity effect correction section 128... Tracking absolute calibration section 129. Exposure map 130 130 Vacuum control section 131. Aperture exchange.

Claims (5)

  Drawing data generating means for generating drawing data for forming a drawing pattern on the sample, exposure map creating means for creating an exposure dose map of an electron beam from the drawing data, and the dose of the electron beam applied to the sample A plurality of drawing data generation units including an electron beam correction unit that performs correction with reference to an exposure amount map, and each drawing data generation unit generates an exposure amount map with different conditions for one drawing pattern, and the electron beam correction unit The electron beam drawing means for performing drawing by irradiating the sample with the electron beam based on the value corrected with reference to the exposure amount map with different conditions, and the exposure amount map with different conditions by the electron beam drawing means A storage unit that sequentially performs drawing based on the image and stores a value corrected by referring to an exposure amount map having an optimum condition as a result of evaluating the drawing result; and evaluating the drawing result As a result, a first electron beam drawing apparatus that performs drawing using a value corrected with reference to an exposure amount map under optimum conditions, and at least one first that performs drawing using a value stored in the storage means And an electron beam drawing apparatus.   2. The electron beam drawing system according to claim 1, wherein the exposure amount maps having different conditions are created in parallel by the respective drawing data generation units.   A plurality of drawing data for forming a drawing pattern on the sample is generated from one drawing pattern, an exposure amount map having different conditions is created from the plurality of drawing data, and the amount of electron beam irradiated to the sample is determined. Correction is made by referring to the exposure map having different conditions, and drawing is performed by irradiating the sample with the electron beam based on the corrected value by referring to the exposure map having different conditions. A drawing method characterized in that drawing is performed sequentially based on different exposure amount maps, and drawing is performed by a plurality of electron beam drawing means using an exposure amount map having an optimum condition as a result of evaluation of drawing results.   Drawing data generating means for generating drawing data for forming a drawing pattern on the sample, exposure map creating means for creating an exposure dose map of an electron beam from the drawing data, and the dose of the electron beam applied to the sample A plurality of drawing data generation units including an electron beam correction unit that performs correction with reference to an exposure amount map, and each drawing data generation unit generates an exposure amount map with different conditions for one drawing pattern, and the electron beam correction unit The electron beam drawing means for performing drawing by irradiating the sample with the electron beam based on the value corrected with reference to the exposure amount map with different conditions, and the exposure amount map with different conditions by the electron beam drawing means A storage unit that sequentially performs drawing based on the image and stores a value corrected by referring to an exposure amount map having an optimum condition as a result of evaluating the drawing result; and evaluating the drawing result As a result, drawing is performed using a value corrected with reference to an exposure amount map under optimum conditions, and the value stored in the storage means is transferred to at least one second electron beam drawing apparatus. An electron beam drawing apparatus. 5. The electron beam drawing apparatus according to claim 4, wherein the exposure amount maps having different conditions are created in parallel by the respective drawing data generation units.

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