JP2005303127A - Electron beam lithographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron beam lithographic apparatus in which temperature changes of a sample, a stage structure member and a sample chamber structure member can be reduced without causing a magnetic field change inside a sample chamber and temperature control can be performed even during irradiation with electron beams. <P>SOLUTION: The temperature of cooling water flowing in a cooling water pipe 17 arranged on a base 11 inside a sample chamber 1 is controlled by a constant temperature water tank 20 arranged outside the sample chamber 1, based on the temperature detected by a temperature sensor 16 that detects the temperature around a sample 7, so as to fix the temperature inside the sample chamber 1. Thus, the temperature inside the sample chamber 1 can be controlled without causing a magnetic field change inside the sample chamber 1, temperature control can be performed even while irradiating the sample 7 with electron beams, and temperature changes of the sample 7 and structure members of a stage 8 and the sample chamber 1 can be reduced. Therefore, a pattern can be accurately lithographed at a predetermined position of the sample 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electron beam drawing apparatus, and more particularly to an electron beam drawing apparatus that performs high-precision drawing while suppressing thermal deformation of a sample, a stage structure member, and a sample chamber structure member.

  In recent years, the degree of integration of semiconductor elements has improved, and it has been required to form a fine pattern with high positional accuracy in an electron beam lithography apparatus. In an electron beam drawing apparatus, in order to form a fine pattern with high positional accuracy, a position error due to thermal deformation during drawing on a sample must be 1 nm or less.

  For this purpose, it is necessary to suppress the temperature change of the sample and the components of the electron beam drawing apparatus to 0.001 ° C. or less.

  As a technique for adjusting the temperature of the sample stage in the electron beam drawing apparatus, there is a technique described in Patent Document 1.

  In the technique described in Patent Document 1, an electric heater is formed on a sample stage, and the current flowing through the heater is controlled so that the temperature difference between the sample and the sample stage is within an allowable range. It is a method of controlling the amount.

JP 2002-353116 A

  However, the technique described in Patent Document 1 aims at canceling the heat generation amount change from the stage operation mechanism by changing the heat generation amount of the electric heating heater. Changes.

  As a result, a magnetic field change occurs in the sample chamber, which affects the electron beam drawing position accuracy.

  For this reason, in the technique described in Patent Document 1, energization to the electric heater is stopped during the irradiation of the electron beam to prevent a magnetic field change due to a change in the heater current.

  However, the amount of frictional heat generated from the stage operation mechanism during electron beam irradiation differs depending on the drawing operation, and is a major cause of thermal deformation due to temperature changes during drawing.

  For this reason, unless temperature control is performed even during electron beam irradiation, it is difficult to further improve the accuracy of electron beam drawing position.

  An object of the present invention is to realize an electron beam lithography apparatus capable of reducing temperature changes of a sample, a stage structure member, and a sample chamber structure member without causing a magnetic field change in the sample chamber, and capable of controlling the temperature even during electron beam irradiation. It is.

In order to achieve the above object, the present invention is configured as follows.
(1) An electron beam drawing apparatus according to the present invention generates an electron beam for drawing to be irradiated on a sample, and converges and deflects the electron beam, and the sample is mounted on the electron beam. On the other hand, it includes a stage for moving the sample, and a sample chamber in which the stage is arranged and the inside is maintained in a vacuum state.
In the electron beam drawing apparatus, a heat transfer means for transferring heat between the inside and outside of the sample chamber by a heat transfer medium, a means for detecting the temperature in the sample chamber, and the temperature detecting means Temperature control means for controlling the temperature of the heat transfer medium of the heat transfer means outside the sample chamber so that the temperature in the sample chamber becomes constant based on the detected temperature.

  (2) Preferably, in (1) above, the heat transfer medium is a liquid.

  (3) Preferably, in (1) above, the heat transfer medium is a light beam.

  (4) Preferably, in (1) above, the heat transfer medium is a rod-shaped solid member having a fluid sealed therein.

  (5) Preferably, in the above (1) to (4), the apparatus further comprises a base member on which the stage is disposed, and a moving unit that allows the stage to move on the base member. Is coated with a film having a small friction coefficient.

  (6) Preferably, in the above (1) to (4), the apparatus includes a base member on which the stage is disposed, and a moving unit that allows the stage to move on the base member. A thermal insulation member that performs thermal insulation with the chamber structural member is provided.

  (7) Preferably, in the above (1) to (4), the stage has a heat storage material.

  According to the present invention, it is possible to reduce the temperature change of the sample, the stage structure member, and the sample chamber structure member without causing a magnetic field change in the sample chamber, and to realize an electron beam drawing apparatus capable of controlling the temperature even during electron beam irradiation. Can do.

  That is, even if there is a change in the amount of heat generated according to the drawing operation, the temperature change of the sample, the stage structure member, and the sample chamber structure member can be reduced without causing a magnetic field change in the sample chamber. A drawing pattern can be drawn with an accuracy of 1 nm or less.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of an electron beam lithography apparatus according to the first embodiment of the present invention.

  In FIG. 1, the electron beam drawing apparatus is mainly composed of a sample chamber 1 and an electron optical column 2. In the electron optical column 2, the electron beam 4 emitted from the electron gun 3 is converged by the electromagnetic lens 5 and deflected by the deflector 6.

  In the sample chamber 1, there is a stage 8 for moving the sample holder 9, and this stage 8 can move on the base 11 in the XY plane direction. The sample holder 9 is fixed on the stage 8 by the electrostatic force of the electrostatic chuck 10, and the sample 7 is fixed to the sample holder 9.

  In order to move the stage 8 on the base 11 in the XY direction, a drive mechanism including a motor 12, a drive rod 13, a guide 14, and a roller 15 is provided.

  The movement of the stage 8 in the X direction and the movement in the Y direction may be the same drive mechanism or different drive mechanisms.

  A temperature sensor 16 is provided on the stage 8. The base 11 is connected to a cooling water piping system (heat transfer means) 17 for controlling the temperature in the sample chamber 1. The cooling water (heat transfer medium) used for the cooling water piping system 17 is supplied from the constant temperature water tank 20.

  A fixing component 19 for fixing the base 11 to the floor plate 18 is provided between the base 11 and the floor plate 18 of the sample chamber 1. FIG. 2 is an enlarged view of the fixing component 19.

  In FIG. 2, the fixing component 19 made of a material having a low thermal conductivity has a columnar shape or a prismatic shape. A screw 21 is inserted from a screw hole formed in the floor plate 18, and the screw 21 is inserted into the base 11, and the base 11 is fixed to the floor plate 18 via the fixing component 19 by the screw 21. With this fixing component 19, the position of the base 11 can be fixed, and heat from the floor plate 18 is not easily transmitted to the base 11.

In FIG. 1, a second system cooling water piping system (not shown) is connected to the electron optical column 2 and the sample chamber 1.
A bar mirror 22 is provided on the stage 8, and an interferometer 23 is provided on the outer side surface of the sample chamber 1, and a length measuring laser 26 is irradiated from the interferometer 23 to the bar mirror 22 inside the sample chamber 1.

  The material of the guide 14 and the roller 15 is a material having high mechanical reliability without affecting the magnetic field distribution, but a thin film (tungsten carbide, cemented carbide, synthetic material) having a low friction coefficient on the rolling contact surface. Diamond). In addition, the sample chamber 1 is configured such that the internal gas is exhausted by the vacuum pump 24.

The operation of the electron beam drawing apparatus configured as described above will be described below.
The inside of the sample chamber 1 is evacuated by a vacuum pump 24 and kept in a vacuum. In the electron beam drawing operation, the irradiation position is slightly changed by deflecting the electron beam 4, the sample 7 is moved by moving the stage 8, and a device pattern is drawn on the entire surface of the sample 7.

  During drawing, heat is generated from each part, such as heat generated by the motor 12 driving the stage 8, rolling friction heat of the roller 15 on the guide 14, and heat generated from the electrostatic chuck 10. Since the amount of heat generated from the motor 12, the guide 14, and the roller 15 depends on the operation of the stage 8, these amounts of heat change from moment to moment depending on the drawing pattern.

  Further, when the condition outside the electron beam drawing apparatus, for example, room temperature changes, the temperature of the structural member of the sample chamber 1 changes. Note that the position of the sample 7 is detected by measuring the distance between the bar mirror 22 on the stage 8 and the interferometer 23 using a laser 26.

  For this reason, when the structural members in the sample chamber 1 such as the sample 7 and the stage 8 are thermally deformed, the pattern cannot be accurately drawn at a predetermined position of the sample 7, which causes a decrease in pattern position accuracy.

  In order to reduce the pattern position error due to thermal deformation during drawing on the sample 7 to 1 nm or less, it is necessary to limit the temperature change of the components of the sample 7, the stage 8 and the electron beam drawing apparatus to 0.001 ° C. or less. .

  Therefore, in the first embodiment of the present invention, the temperature of the stage 8 is measured by the temperature sensor 16, and the temperature fluctuation of the stage 8 is 0.001 ° C. or less even if the heat generation amount changes according to the drawing operation. As described above, the temperature and flow rate of the cooling water flowing through the cooling water piping system 17 installed in the base 11 is controlled by heating / cooling control means (not shown) in the constant temperature bath 20 arranged outside the sample chamber 1. ing.

  In addition, since the fixing component 19 which is difficult to transmit heat is provided between the base 11 and the floor plate 18 of the sample chamber 1, there is no influence that the temperature change of the base 11 is transmitted to the floor plate 18 of the sample chamber 1.

  Further, the electron gun 3 in the electron optical column 2 also generates heat that changes in accordance with the drawing operation. However, the temperature fluctuations of the electron optical column 2 and the sample chamber 1 are 0.001 ° C. or less. The temperature and flow rate of the cooling water flowing through the cooling water piping systems of the two systems are controlled by the cooling water temperature and flow rate control means (not shown) according to the temperature detection signal from the temperature sensor 16.

  Further, since the rolling contact surfaces of the guide 14 and the roller 15 are coated with a thin film having a low friction coefficient, the amount of heat generated by friction can be reduced and the temperature change can be reduced.

  As described above, according to the first embodiment of the present invention, the temperature of the cooling water flowing in the cooling water pipe 17 disposed in the base 11 in the sample chamber 1 is detected by the temperature sensor 16 that detects the temperature in the vicinity of the sample 7. Based on the temperature detected by the above, the temperature is controlled by the constant temperature water tank 20 arranged outside the sample chamber 1 so that the temperature in the sample chamber 1 becomes constant.

  Therefore, the temperature can be controlled even during the electron beam irradiation, the temperature change of the sample 7, the stage 8, and the sample chamber 1 structural member can be reduced, and the pattern can be drawn accurately at a predetermined position of the sample 7.

  In the example described above, cooling water is used as the cooling medium. However, the cooling medium is not limited to water, and other liquids can be used.

  FIG. 3 is a schematic configuration diagram of an electron beam lithography apparatus according to the second embodiment of the present invention.

  In this 2nd Embodiment, the same code | symbol is attached | subjected to the member same as the example shown in FIG. 1, and the detailed description is abbreviate | omitted.

  In the second embodiment, the stage 8 is irradiated with irradiation light (heat transfer medium) from a heating lamp (heat transfer means) 30 provided outside the sample chamber 1.

  The irradiation light path 31 from the heating lamp 30 is formed by a hole formed in the floor plate 18, a lens (not shown) in the sample chamber 1, a mirror 32 in the sample chamber 1, an optical fiber (not shown), and the like. Yes.

  The temperature of the stage 8 is measured by the temperature sensor 16, and the irradiation light amount of the heating lamp 30 is controlled so that the temperature of the stage 8 does not fluctuate even if the heat generation amount changes according to the drawing operation.

  When a magnetic field change occurs in the sample chamber 1, the deflection of the electron beam is affected, and the drawing position accuracy deteriorates. Therefore, in the second embodiment, the heating lamp 30 is arranged outside the sample chamber 1 so that no magnetic field change occurs in the sample chamber 1.

  Further, in the second embodiment, the temperature of the cooling water flowing through the cooling water piping system 17 of the base 11 is constant regardless of the temperature detected by the temperature sensor 16, and it is not necessary to control the temperature and flow rate. .

  According to the second embodiment, the heating amount control of the heating lamp 30 has an effect that the temperature control can be performed at a higher speed than the temperature control of the cooling water.

  In the second embodiment, the heating amount control by the heating lamp is used. However, the stage 8 is provided with a component (for example, a roller) that is moved by an external force, and frictional heat generated between the moved component and the stage. The amount can be controlled to suppress the temperature fluctuation in the sample chamber 1.

  In the second embodiment of the present invention shown in FIG. 3, the guide 37 is formed on the stage 8 side and the roller 38 is formed on the base 11 side in the drive mechanism for moving the stage 8.

  It has been experimentally found that the roller 38 generates a large amount of frictional heat between the guide 37 and the roller 38, and the roller 38 is formed on the base 11 side whose temperature is controlled by water cooling. This is because the frictional heat generation can be efficiently cooled, and the temperature change of the stage 8 can be reduced.

  As described above, also in the second embodiment of the present invention, the same effect as that of the first embodiment can be obtained.

  In the second embodiment, the electrostatic chuck 10 may be irradiated with the irradiation light from the heating lamp 30 via a mirror. However, irradiating the sample with the irradiation light from the heating lamp 30 via the mirror 32 is avoided. This is to avoid partial heating of the sample 7.

FIG. 4 is a schematic configuration diagram of a main part of an electron beam lithography apparatus according to the third embodiment of the present invention, and is an enlarged view of a drive rod 13 that moves the stage 8.
In FIG. 4, a heat pipe (heat transfer means, heat transfer medium (a liquid in which the boiling liquid is contained inside the tubular solid member)) 40 is provided in the drive rod 13. One end 41 of the heat pipe 40 is located in the vicinity of the stage 8, and the other end 42 of the heat pipe 40 is located outside the sample chamber 1.

  A heat heater 43 is attached to a portion 42 of the heat pipe 40 located outside the sample chamber 1.

  Other configurations are the same as the example shown in FIG. However, in the third embodiment, the heating lamp 30 and the mirror 32 are not provided.

  In the third embodiment, the temperature of the stage 8 is measured by the temperature sensor 16, and the amount of heat generated by the external heater 43 is set so that the temperature of the stage 8 does not fluctuate even if the amount of heat generated changes according to the drawing operation. It is controlled by control means (not shown). With the heat pipe 40, the amount of heat generated by the external heater 43 is quickly transmitted to the stage 8.

  In the third embodiment, since the heater 43 is provided outside the sample chamber 1, a magnetic field change due to the heater 43 does not occur inside the sample chamber 1.

  Therefore, also in the third embodiment, the temperature change of the sample, the stage structure member, and the sample chamber structure member can be reduced without causing a magnetic field change in the sample chamber. A controllable electron beam drawing apparatus can be realized.

  Furthermore, according to the third embodiment, there is an effect that the amount of heat generated in the sample chamber 1 can be controlled at high speed by the external heater 43.

  The heat pipe 40 may be formed independently of the drive rod 13, and instead of the heat pipe 40, a vibration type heat transport device (sometimes referred to as a dream pipe), other high heat transport devices, or a high heat conduction member. Even if is used, an equivalent effect can be obtained.

FIG. 5 is a schematic configuration diagram of a main part of an electron beam lithography apparatus according to the fourth embodiment of the present invention, and is a perspective view of a stage 8 used in the electron beam lithography apparatus.
In FIG. 5, a heat storage material 45 (calcium chloride, a polymer material, a low melting point metal material, etc.) is disposed inside the stage 8. Other configurations are the same as the example shown in FIG. However, in the third embodiment, the heating lamp 30 and the mirror 32 are not provided.

  In FIG. 5, when the amount of heat generation increases in accordance with the drawing operation to increase the temperature, heat is stored in the heat storage material 45 and the temperature increase is suppressed. Moreover, when the calorific value is reduced, heat is released from the heat storage material 45 and the temperature drop is suppressed. The stage temperature can be kept constant by the heat storage material.

  In the fourth embodiment, the cooling water temperature may be controlled based on the temperature detected by the temperature sensor 16 as in the example of FIG.

  Further, in the fourth embodiment, similarly to the example shown in FIGS. 3 and 4, the stage 8 is irradiated with light, or the stage 8 is heated and cooled by a heat pipe or the like, and the sample chamber 1 is heated. The temperature may be controlled to be constant.

  FIG. 6 is a graph showing the result of calculating the effect of the present invention by numerical simulation.

  As a calculation condition, the stage is stopped and placed in a steady state before placing the sample on the electrostatic chuck, and the time change of the electrostatic chuck temperature after the frictional heat is generated in the drawing operation is calculated. did.

  Further, it was assumed that the total amount of frictional heat generation was 0.1 W, the temperature of the sample to be placed was equal to the electrostatic chuck temperature, and there was no change in the ambient temperature of the sample chamber 1 structural member or the like.

  In FIG. 6, the vertical axis represents the change from the initial temperature as the electrostatic chuck temperature change, and the horizontal axis represents the elapsed time. Further, a result when the temperature control of the cooling water is not performed is shown by a line 51. As can be seen from this line 51, there is a temperature change of 0.05 ° C. due to frictional heat generation.

  Line 52 shows the result of temperature control according to the first embodiment of the present invention. As indicated by the line 52, the temperature change of the electrostatic chuck is 0.001 ° C. or lower.

  A line 53 shows the result when the temperature is controlled according to the second embodiment of the present invention. As indicated by a line 53, the temperature change of the electrostatic chuck is 0.001 ° C. or less.

  Thus, it can be understood that when the temperature is controlled according to the present invention, the electrostatic chuck temperature fluctuation is suppressed as compared with the case where the temperature is not controlled. Therefore, even during drawing, temperature control can be suppressed by controlling the temperature, and drawing accuracy can be improved.

1 is a schematic configuration diagram of an electron beam drawing apparatus according to a first embodiment of the present invention. FIG. 2 is an enlarged view of a fixed part of the electron beam drawing apparatus shown in FIG. 1. It is a schematic block diagram of the electron beam drawing apparatus which is the 2nd Embodiment of this invention. It is a principal part schematic block diagram of the 3rd Embodiment of this invention. It is a principal part schematic block diagram of the 4th Embodiment of this invention. It is a graph which shows the temperature fluctuation inhibitory effect by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sample chamber 2 Electron optical barrel 3 Electron gun 4 Electron beam 5 Electromagnetic lens 6 Deflector 7 Sample 8 Stage 9 Sample holder 10 Electrostatic chuck 11 Base 12 Motor 13 Drive rod 14, 37 Guide 15, 38 Roller 16 Temperature sensor 17 Cooling water piping system 18 Sample room floor plate 19 Fixed part 20 Thermostatic water tank 21 Screw 22 Bar mirror 23 Interferometer 24 Vacuum pump 26 Measuring laser 30 Heating lamp 32 Mirror 40 Heat pipe 43 Heating heater 45 Heat storage material

Claims (7)

An electron optical barrel that generates a drawing electron beam to be irradiated onto the sample, converges and deflects the electron beam, a stage that mounts the sample and moves the sample with respect to the electron beam, and this stage In an electron beam lithography apparatus having a sample chamber disposed therein and the interior maintained in a vacuum state,
Heat transfer means for transferring heat between the inside and outside of the sample chamber by means of a heat transfer medium;
Means for detecting the temperature in the sample chamber;
Temperature control means for controlling the temperature of the heat transfer medium of the heat transfer means outside the sample chamber so that the temperature in the sample chamber is constant based on the temperature detected by the temperature detection means;
An electron beam drawing apparatus comprising:   2. The electron beam drawing apparatus according to claim 1, wherein the heat transfer medium is a liquid.   2. The electron beam drawing apparatus according to claim 1, wherein the heat transfer medium is a light beam.   2. The electron beam drawing apparatus according to claim 1, wherein the heat transfer medium is a bar-shaped solid member having a fluid sealed therein.   5. The electron beam drawing apparatus according to claim 1, further comprising: a base member on which the stage is disposed; and a moving unit that allows the stage to move on the base member. An electron beam drawing apparatus characterized in that a film having a small friction coefficient is coated on the surface of the electron beam.   5. The electron beam lithography apparatus according to claim 1, further comprising: a base member on which the stage is disposed; and a moving unit that allows the stage to move on the base member. An electron beam drawing apparatus comprising: a heat insulating member that performs heat insulation between the sample chamber structural member and the sample chamber structural member.   5. The electron beam drawing apparatus according to claim 1, wherein the stage has a heat storage material. 6.

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