JP2009231334A - Charged particle beam drawing device and charged particle beam drawing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device or a method which can measure a temperature substantially equivalent to that of a substrate to actually be drawn. <P>SOLUTION: The drawing device 100 includes: a drawing chamber 103; an electronic mirror cylinder 102 provided with an optical system which is placed above the drawing chamber 103 and emits an electron beam 200 into the drawing chamber 103; an isothermal layer 106 surrounding the drawing chamber 103; an XY stage 105 placed in the drawing chamber 103; a plurality of supporting pins 104 which are mounted to the XY stage 105 to directly support a substrate 101; and a plurality of temperature sensors 108 provided at the supporting pins 104. Thus, a temperature substantially equivalent to that of a substrate to actually be drawn can be measured. Even during the substrate is drawn, the temperature substantially equivalent to the substrate temperature can be measured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a charged particle beam drawing apparatus and a charged particle beam drawing method, for example, a mechanism and a drawing method for controlling the temperature in a drawing apparatus that draws using an electron beam.

  Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is an extremely important process for generating a pattern among semiconductor manufacturing processes. In recent years, with the high integration of LSIs, circuit line widths required for semiconductor devices have been miniaturized year by year. In order to form a desired circuit pattern on these semiconductor devices, a highly accurate original pattern (also referred to as a reticle or a mask) is required. Here, the electron beam (electron beam) drawing technique has an essentially excellent resolution, and is used for producing a high-precision original pattern.

FIG. 5 is a conceptual diagram for explaining the operation of a conventional variable shaping type electron beam drawing apparatus.
In the first aperture 410 in the variable shaping electron beam (EB (Electron beam) drawing apparatus), a rectangular, for example, rectangular opening 411 for forming the electron beam 330 is formed. 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, which is irradiated from the charged particle source 430 and that of the first aperture 410. The electron beam 330 that has passed through the opening 411 is deflected by a deflector, passes through a part of the variable shaping opening 421 of the second aperture 420, and continuously in a predetermined direction (for example, the X direction). The sample 340 mounted on the moving stage is irradiated, that is, the opening 411 of the first aperture 410 and the second aperture 4. A rectangular shape that can pass through both of the 20 variable shaping openings 421 is drawn in the drawing area of the sample 340 mounted on a stage that continuously moves in the X direction. A method of creating an arbitrary shape by passing through both the variable shaping opening 421 of the second aperture 420 is referred to as a variable shaping method.

  Here, drawing of a semiconductor pattern serving as a sample on a mask is usually performed by placing the mask on an XY stage in a drawing chamber (chamber) provided in a drawing apparatus. Here, when the temperature of the mask changes during drawing, the size of the mask changes. Thereby, the drawing position accuracy is deteriorated. Therefore, it is important to keep the mask at a uniform temperature during drawing. Further, the fact that the temperature of the mask does not change after bringing the mask into the chamber is also important from the viewpoint of ensuring a uniform temperature and shortening the drawing time.

  Conventionally, the temperature in the chamber is measured by a thermometer attached to the inner wall of the chamber. Also, a thermometer has been arranged on the stage for moving the mask for temperature control of the stage. However, since the temperature measured by these thermometers is not the temperature of the mask, it is necessary to grasp the temperature of the mask separately. For this purpose, a dummy substrate in which a thermometer was embedded was created, and this dummy substrate was first placed on the stage in the chamber. Prior to drawing, the temperature of the dummy substrate is preliminarily measured to control the temperature of the mask actually drawn.

  However, since the temperature of the dummy substrate is the temperature in the state before the drawing, the temperature of the mask during the drawing cannot be measured. Therefore, it is difficult to grasp the temperature change of the mask after bringing the mask into the chamber. Furthermore, since the thermometer is embedded in the dummy substrate, the substrate structure is partially different from the mask to be drawn, and there is a drawback that the temperature distribution in the drawn mask and the substrate changes. For this reason, if the temperature of the dummy substrate is simulated as it is with the temperature of the mask actually drawn, there is a problem that the temperature distribution is different.

Here, a mask that expands and contracts due to thermal expansion caused by electron beam irradiation in an electron beam mask drawing apparatus that draws a circuit pattern or the like by irradiating an electron beam onto a mask having a rectangular shape in relation to the temperature change of the mask. A technique is disclosed in the literature for measuring the length of both of the opposite sides using laser light (see, for example, Patent Document 1). This technique is based on the premise that the dimensions of the mask change due to changes in the temperature of the mask, and does not adjust the temperature so as not to change the dimensions of the mask.
JP 2007-264052 A

  As described above, there is a problem that the temperature state of the mask cannot be grasped at the temperature at a position away from the mask, such as the temperature of the inner wall of the chamber or the stage temperature. Furthermore, since the temperature of the dummy substrate is the temperature in the state before drawing, there is a problem that the temperature of the mask during drawing cannot be measured. Further, since the dummy substrate is partially different from the mask on which the substrate is drawn, the temperature of the dummy substrate has a problem that the temperature and temperature distribution of the mask actually drawn differ. In production management, it is desirable to grasp the change in mask temperature during drawing.

  Therefore, an object of the present invention is to provide an apparatus or method that can overcome the above-described problems and that can measure a temperature substantially equal to the temperature of a substrate that is actually drawn.

A charged particle beam drawing apparatus according to one embodiment of the present invention includes:
A chamber;
A lens barrel disposed above the chamber and having an optical system for irradiating a charged particle beam in the chamber;
An isothermal layer surrounding the chamber;
A stage located in the chamber;
A plurality of support members mounted on the stage and directly supporting the substrate;
A plurality of temperature sensors arranged on a plurality of support members;
It is provided with.

  Since the plurality of temperature sensors are arranged on the plurality of support members that directly support the substrate, it is possible to measure a temperature substantially equivalent to the temperature of the substrate actually drawn. Moreover, since the temperature sensor is not arranged on the substrate, the problem that the temperature distribution is different can be solved.

And based on the outputs of the plurality of temperature sensors, a temperature measurement unit that measures the temperature near the substrate,
An adjustment unit for adjusting the temperature of the thermostatic layer based on the temperature near the substrate;
It is preferable to further include

  Further, the temperature measuring unit preferably measures the temperature in the vicinity of the substrate in real time while drawing the substrate. The temperature sensor is embedded in the support member.

The charged particle beam drawing method of one embodiment of the present invention includes:
Measuring a temperature of a substrate directly supported by a plurality of support members mounted on a stage in a chamber using temperature sensors disposed on the plurality of support members;
Adjusting the temperature of the thermostatic layer surrounding the chamber based on the measured temperature of the substrate;
A step of drawing a substrate directly supported by a plurality of support members using a charged particle beam with the temperature of the thermostatic layer adjusted;
It is provided with.

  With this configuration, the substrate temperature can be adjusted to a desired temperature by adjusting the temperature of the thermostatic layer according to the change in temperature based on the measured temperature of the substrate.

  According to one embodiment of the present invention, a temperature substantially equal to the temperature of a substrate that is actually drawn can be measured. The substrate temperature can be adjusted to a desired temperature by adjusting the temperature of the thermostatic layer based on the temperature change. Furthermore, a temperature substantially equal to the temperature of the substrate can be measured during drawing.

  Hereinafter, in each embodiment, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and may be a beam using other charged particles such as an ion beam.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the first embodiment.
In FIG. 1, the drawing apparatus 100 includes a drawing unit 150, a temperature measurement circuit 110, a temperature control circuit 112, a temperature regulator 114, and a drawing control circuit 160. The drawing apparatus 100 is an example of a charged particle beam drawing apparatus. In particular, here, a variable shaping type electron beam drawing apparatus is shown. The drawing unit 150 includes a drawing chamber 103 (chamber) and an electron column 102 disposed above the drawing chamber 103 (chamber). In the electron column 102, 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, and a deflector 208 are arranged. Yes. An electron beam 200 is introduced into the drawing chamber 103 by an electron optical system such as 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, and a deflector 208. Irradiated. On the other hand, an XY stage 105 is disposed in the drawing chamber 103, and a plurality of support pins 104 are mounted on the XY stage 105. The plurality of support pins 104 support the substrate 101 as a sample in direct contact. The constant temperature layer 106 is disposed so as to surround the drawing chamber 103. Further, each support pin 104 is provided with a temperature sensor 108. Each temperature sensor 108 is connected to a temperature measurement circuit 110, and the temperature near the substrate 101 is measured by the temperature measurement circuit 110. The temperature adjuster 114 adjusts the temperature of the thermostatic layer 106 based on the temperature near the substrate. The temperature measurement circuit 110 and the temperature regulator 114 are connected to the temperature control circuit 112 via a bus (not shown). In FIG. 1, description of components other than those necessary for describing the first embodiment is omitted. It goes without saying that the drawing apparatus 100 usually includes other necessary configurations.

  The electron beam 200 emitted from the electron gun 201 is collected by the illumination lens 202 and illuminates the entire first aperture 203 having a rectangular hole, for example, a rectangular hole. 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 is movably disposed on the substrate 101 on the XY stage 105. The desired position is irradiated. Further, the inside of the electron column 102 and the drawing chamber 103 in which the XY stage 105 is arranged are evacuated by a vacuum pump (not shown) to form a vacuum atmosphere in which the pressure is lower than the atmospheric pressure. The drawing unit 150 is controlled by the drawing control circuit 160.

FIG. 2 is a conceptual diagram illustrating the arrangement configuration of the support pins and the temperature sensor in the first embodiment.
In FIG. 2, the support pin 104 serving as a support member is disposed on the XY stage 105. The support pin 104 is formed in a convex shape with a smooth curved upper portion. Then, the top vertex is directly supported by the substrate 101 and is simply supported. A temperature sensor 108 is embedded in the support pin 104. In particular, the temperature sensor 108 is embedded so as to be inserted toward the substrate 101 from the side opposite to the substrate 101. Insertion toward the substrate 101 from the side opposite to the substrate 101 can prevent the substrate 101 from becoming an obstacle to support. At that time, it is preferable that the temperature sensor 108 is inserted deeply as close to the substrate 101 as possible. As described above, by embedding the temperature sensor 108 in the support pin 104, it is possible to measure the temperature immediately near the contact point of the substrate 101. Therefore, a temperature substantially equal to that of the substrate 101, in other words, a substantially equivalent temperature can be measured. Here, for example, since a temperature change of 0.01 degrees affects the drawing accuracy, the temperature sensor is preferably a highly accurate sensor. For example, it is preferable to use a platinum resistance thermometer. However, the present invention is not limited to this. For example, a thermistor or a thermocouple may be used. Alternatively, an IC type temperature sensor may be used. In a non-contact type temperature sensor such as a radiation temperature type, it is difficult to measure a temperature change of, for example, 0.01 degrees. However, by installing these contact type temperature sensors, a non-contact type temperature sensor is provided. Temperature can be measured with higher accuracy.

FIG. 3 is a conceptual diagram when the substrate side is viewed from above the substrate in the drawing chamber according to the first embodiment.
As shown in FIG. 3, the substrate 101 is preferably supported at three points by three support pins 104. A temperature sensor 108 is embedded in each support pin 104. As described above, the temperature distribution in the surface of the substrate 101 to be actually drawn can be grasped by measuring the temperature closest to the contact point of the substrate 101 by the plurality of temperature sensors 108. Therefore, it is possible to grasp the more accurate substrate 101 temperature. Further, each support pin 104 simply supports the substrate 101 from the back side, so that it is disposed at a position where it cannot be seen from above the substrate. As described above, since the temperature sensor 108 is inserted into each support pin 104 from the side opposite to the substrate 101 toward the substrate 101, the temperature sensor 108 is also arranged at a position where it cannot be seen from above the substrate. Can do. As described above, by arranging the temperature sensor 108 at a position that cannot be seen from above the substrate from the XY stage 105 side, for example, charge-up due to the electron beam 200 occurs in the temperature sensor 108 or occurs due to the objective lens 207 or the like. Generation of eddy current due to the magnetic field in the temperature sensor 108 can be suppressed. Moreover, even if the temperature sensor 108 generates particles or the like by arranging them on the lower surface side that cannot be seen from the upper surface serving as the drawing surface, the influence on the drawing surface of the substrate 101 can be suppressed or eliminated.

  Using the drawing apparatus 100 as described above, drawing is performed as follows. First, the temperature of the drawing chamber 103 is adjusted so as to be a constant temperature by the thermostatic layer 106. In this state, the substrate 101 is carried into the drawing chamber 103. The substrate 101 is directly supported by a plurality of support pins 104 mounted on the XY stage 105. From this state, the temperature of the substrate 101 is measured using the temperature sensors 108 arranged on the plurality of support pins 104.

  Here, the temperature of the substrate 101 is desirably kept constant at the temperature when the substrate 101 is carried into the drawing chamber 103. This is because if the temperature changes, an error occurs in the drawing position due to thermal expansion and the like, and an error occurs in the size and position of the drawn pattern. However, the temperature of the substrate 101 may be shifted from the time of loading in the drawing chamber 103 and stabilized.

  Therefore, the temperature of the constant temperature layer 106 surrounding the drawing chamber 103 is adjusted based on the measured temperature of the substrate 101. Since the temperature measurement circuit 110 measures the temperature near the substrate 101 based on the outputs of the plurality of temperature sensors 108, the temperature control circuit 112 inputs temperature data from the temperature measurement circuit 110. Then, the temperature control circuit 112 outputs a control signal for setting the temperature of the thermostatic layer 106 to the temperature adjuster 114 so that the temperature of the substrate 101 becomes the temperature at the time when the substrate 101 is loaded. The temperature adjuster 114 receives the control signal based on the temperature in the vicinity of the substrate and adjusts the temperature of the thermostatic layer 106.

FIG. 4 is a diagram illustrating an example of a temperature change of the substrate in the first embodiment.
In FIG. 4, when the stable temperature of the substrate 101 in the drawing chamber 103 decreases from the temperature T ₀ of the substrate 101 at the time when the substrate 101 is carried into the drawing chamber 103 to, for example, the temperature T ₁ , the temperature control circuit 112 Then, a control signal is output to the temperature regulator 114 so as to raise the temperature of the constant temperature layer 106 so that the temperature of the substrate 101 becomes the temperature T ₀ . Thereby, for example, a temperature change of 0.01 degrees can be eliminated. Conversely, for example, when increased from a temperature T ₀ to the temperature T _2, the temperature control circuit 112, the temperature of the substrate 101, so that the temperature T _0, temperature control signal to lower the temperature of the thermostatic bath 106 Output to the adjuster 114.

In this way, in a state where the temperature of the substrate 101 is stable at the temperature T ₀ , the drawing unit 150 directly uses the electron beam 200 by the plurality of support pins 104 mounted on the XY stage 105 in the drawing chamber. Drawing of the supported substrate 101 is started. Since the temperature of the actually drawn substrate 101 can be measured, it is possible to grasp the state where the temperature of the actually drawn substrate 101 is stable. Therefore, the drawing start time can be determined not by the predicted value but by the actually measured value. Therefore, extra drawing standby time can be saved and drawing time can be shortened.

  Further, during the drawing, the temperature of the substrate 101 is continuously measured using the temperature sensors 108 arranged on the plurality of support pins 104. By measuring the temperature even during drawing, if the temperature of the substrate 101 changes during drawing, it can be detected as NG. Conventionally, pattern defects can be grasped by measuring pattern dimensions through a process such as development and etching after drawing. On the other hand, in the first embodiment, a pattern defect can be grasped without performing another process during drawing or immediately after drawing due to a temperature change of the substrate 101 during drawing.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, when the temperature of the substrate 101 changes during drawing, it is preferable to correct the drawing position in accordance with the change. For example, the position error can be calculated by multiplying the linear expansion coefficient of the substrate 101 by the temperature change. What is necessary is just to irradiate a beam to the position which corrected the error part.

  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, although the description of the control unit configuration for controlling the drawing apparatus 100 is omitted, it goes without saying that the required control unit configuration is appropriately selected and used.

  In addition, all charged particle beam drawing apparatuses and charged particle beam drawing methods that include elements of the present invention and that 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 configuration of a drawing apparatus according to Embodiment 1. FIG. 4 is a conceptual diagram illustrating an arrangement configuration of support pins and a temperature sensor in Embodiment 1. FIG. 3 is a conceptual diagram when the substrate side is viewed from above the substrate in the drawing chamber according to Embodiment 1. FIG. 6 is a diagram illustrating an example of a temperature change of a substrate in Embodiment 1. FIG. It is a conceptual diagram for demonstrating operation | movement of the conventional variable shaping type | mold electron beam drawing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Drawing apparatus 101 Substrate 102 Electron barrel 103 Drawing chamber 104 Support pin 105 XY stage 106 Constant temperature layer 108 Temperature sensor 110 Temperature measurement circuit 112 Temperature control circuit 114 Temperature regulator 150 Drawing unit 160 Drawing control circuit 200 Electron beam 201 Electron gun 202 Illumination lenses 203 and 410 First aperture 204 Projection lenses 205 and 208 Deflectors 206 and 420 Second aperture 207 Objective lens 330 Electron beam 340 Sample 411 Opening 421 Variable shaped opening 430 Charged particle source

Claims (5)

A chamber;
A lens barrel disposed above the chamber and having an optical system for irradiating a charged particle beam in the chamber;
An isothermal layer surrounding the chamber;
A stage disposed in the chamber;
A plurality of support members mounted on the stage and directly supporting the substrate;
A plurality of temperature sensors disposed on the plurality of support members;
A charged particle beam drawing apparatus comprising: A temperature measuring unit for measuring a temperature near the substrate based on outputs of the plurality of temperature sensors;
An adjustment unit that adjusts the temperature of the constant temperature layer based on the temperature in the vicinity of the substrate;
The charged particle beam drawing apparatus according to claim 1, further comprising:   3. The charged particle beam drawing apparatus according to claim 1, wherein the temperature measuring unit measures the temperature in the vicinity of the substrate in real time during the drawing of the substrate.   The charged particle beam drawing apparatus according to claim 1, wherein the temperature sensor is embedded in the support member. Measuring a temperature of a substrate directly supported by a plurality of support members mounted on a stage in a chamber using a temperature sensor disposed on the plurality of support members;
Adjusting the temperature of the thermostatic layer surrounding the chamber based on the measured temperature of the substrate;
Drawing a substrate directly supported by the plurality of support members using a charged particle beam with the temperature of the thermostatic layer adjusted;
A charged particle beam drawing method comprising:

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