JP2014033075A - Electric charge particle beam lithography device and pattern inspection device - Google Patents

Abstract

Deterioration of apparatus accuracy due to vibration of a laser interferometer is suppressed.
A charged particle beam drawing apparatus includes a movable stage that supports a sample, and a laser interferometer 12 that measures a relative distance between the stage in the moving direction of the stage using a laser beam. The laser interferometer 12 is a polarization beam splitter 12c that is an example of a beam splitter that separates laser light into measurement light L1 and reference light L2, and the reference light L2 separated by the polarization beam splitter 12c is parallel to the measurement light L1. And a fixed mirror 12f that reflects the reference light L2 reflected by the reflecting portion 12d toward the reflecting portion 12d in parallel with the measurement light L1.
[Selection] Figure 3

Description

  The present invention relates to a charged particle beam drawing apparatus and a pattern inspection apparatus.

  With the recent high integration and large capacity of large scale integrated circuits (LSIs), circuit line widths required for semiconductor devices are becoming increasingly smaller. In order to form a desired circuit pattern on a semiconductor device, a lithography technique is used. In this lithography technique, pattern transfer using an original pattern called a mask (reticle) is performed. In order to manufacture a high-accuracy mask used for this pattern transfer, a charged particle beam drawing apparatus having an excellent resolution is used.

  As an example of this charged particle beam drawing apparatus, an electron beam is deflected and irradiated to a predetermined position of a sample on the stage based on the position of the stage while moving a stage on which a sample such as a mask or a blank is moved. However, charged particle beam drawing apparatuses that draw patterns on a sample on a stage have been developed. In addition, a pattern inspection apparatus that inspects a pattern of a sample on the stage based on the position of the stage has been developed.

  In such a charged particle beam drawing apparatus or pattern inspection apparatus, a laser interferometer having a plurality of optical components such as a polarizing beam splitter, a λ / 4 plate, and a reflecting mirror is usually used as a measuring instrument for measuring the position of the stage. It is used. A λ / 4 plate and a reflecting mirror are directly stacked on the side surface of the polarizing beam splitter. The laser beam incident on the polarization beam splitter is divided by the polarization beam splitter into measurement light (measurement light) directed to the stage and reference light directed to the reflecting mirror. Thereafter, the measurement light and the reference light reflected by the stage and the reflecting mirror are combined again by the polarization beam splitter to become interference light. At this time, the change in the optical path length of the measurement light due to the movement of the stage brings about a change in the phase of the measurement light, resulting in a frequency variation in the interference light. The stage position is measured from this frequency variation (interference fringes generated by the optical path difference between the measurement light and the reference light).

  As described above, the laser interferometer is a measuring instrument that measures the relative distance between itself and the stage. When the laser interferometer, that is, the beam splitter vibrates, a measurement error occurs. In addition, in order to suppress vibration of a measuring device that measures a mark, not vibration of an optical component such as a beam splitter, a technique of providing a mass damper in a housing of the measuring device has been proposed (for example, see Patent Document 1).

JP 2006-147899 A

  However, when a mass damper is provided in the housing of the measuring device that measures the marks as described above, it is difficult to suppress vibration of minute optical components compared to the housing, and vibration of the optical components in the housing is suppressed. It is difficult to suppress completely. In particular, vibration that does not cause a problem in the measurement device that measures the mark can also be a problem in the laser interferometer. If the measurement accuracy of the laser interferometer decreases due to vibration of optical components such as a beam splitter, the device accuracy ( (Drawing accuracy or inspection accuracy) decreases.

  Here, in order to suppress the vibration of the optical component, for example, when the optical component is firmly fixed by the mounting member, a strong external force is applied to the optical component, and the external force causes distortion of the optical component (optical distortion). For this reason, the optical performance of the optical component is lowered, and the measurement accuracy of the laser interferometer is lowered. Furthermore, since the optical component and the mounting member are in close contact with each other, distortion (optical strain) of the optical component occurs due to thermal expansion or contraction of the mounting member, which also decreases the optical performance of the optical component, and the measurement accuracy of the laser interferometer Will be lower. Therefore, it is necessary to avoid firmly fixing the optical component with an attachment member or the like.

  The problem to be solved by the present invention is to provide a charged particle beam drawing apparatus and a pattern inspection apparatus capable of suppressing a decrease in apparatus accuracy due to vibration of a laser interferometer.

  A charged particle beam drawing apparatus according to an embodiment of the present invention includes a movable stage that supports a sample, and a laser interferometer that measures a relative distance between the stage in the moving direction of the stage with laser light, and a laser interferometer. Includes a beam splitter that separates the laser light into measurement light and reference light, a reflection part that reflects the reference light separated by the beam splitter in parallel to the measurement light, and directs the reference light reflected by the reflection part to the reflection part. And a fixed mirror that reflects in parallel with the measurement light.

  In the charged particle beam drawing apparatus, it is desirable that the reflecting portion is provided on a side surface of the beam splitter.

  In the charged particle beam drawing apparatus, the weight of the reflecting portion is preferably 10% or less of the weight of the beam splitter.

  The charged particle beam drawing apparatus preferably further includes a fixed drawing chamber for accommodating the stage, and the fixed mirror is fixed to the wall of the drawing chamber.

  A pattern inspection apparatus according to an embodiment of the present invention includes a movable stage that supports a sample, and a laser interferometer that measures a relative distance between the stage in the moving direction of the stage using a laser beam. A beam splitter that separates laser light into reference light and measurement light, a reflection part that reflects the reference light separated by the beam splitter in parallel to the measurement light, and the reference light reflected by the reflection part is measured toward the reflection part. And a fixed mirror that reflects in parallel to the light.

  According to the present invention, it is possible to suppress a decrease in apparatus accuracy due to vibration of the laser interferometer.

1 is a diagram illustrating a schematic configuration of a charged particle beam drawing apparatus according to a first embodiment. It is a figure which shows schematic structure of the stage and laser interferometer which concern on 1st Embodiment. It is a figure which shows schematic structure of the laser interferometer which concerns on 1st Embodiment. It is a figure which shows the comparative example of the laser interferometer which concerns on 1st Embodiment. It is a figure which shows schematic structure of the pattern inspection apparatus which concerns on 2nd Embodiment.

(First embodiment)
A first embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the charged particle beam drawing apparatus 1 according to the first embodiment includes a drawing unit 2 that performs drawing using a charged particle beam, and a control unit 3 that controls the drawing unit 2. The charged particle beam drawing apparatus 1 is an example of a variable shaping type drawing apparatus using, for example, an electron beam as a charged particle beam. The charged particle beam is not limited to the electron beam, and may be another charged particle beam such as an ion beam.

  The drawing unit 2 includes a drawing chamber 2a that accommodates a sample W to be drawn, and an optical barrel 2b that is connected to the drawing chamber 2a. The optical barrel 2b is provided on the upper surface of the drawing chamber 2a, and shapes and deflects an electron beam and irradiates the sample W in the drawing chamber 2a. At this time, the inside of both the drawing chamber 2a and the optical barrel 2b is depressurized to be in a vacuum state.

  A stage 11 that supports the sample W is provided in the drawing chamber 2a. The stage 11 is formed so as to be movable by a moving function in the X-axis direction and the Y-axis direction (hereinafter simply referred to as the X direction and the Y direction) orthogonal to each other in a horizontal plane, and on the mounting surface of the stage 11 For example, a sample W such as a mask or a blank is placed. A laser interferometer 12 is provided on the outer periphery of the drawing chamber 2a. The laser interferometer 12 is a measuring instrument that measures the relative distance between itself and the stage 11, that is, the separation distance.

  In the optical barrel 2b, an emission part 21 such as an electron gun for emitting an electron beam B, an illumination lens 22 for condensing the electron beam B, a first shaping aperture 23 for beam shaping, and a projection purpose The projection lens 24, the beam shaping shaping deflector 25, the beam shaping second shaping aperture 26, the objective lens 27 that focuses the beam on the sample W, and the beam shot position with respect to the sample W. A sub-deflector 28 and a main deflector 29 are arranged.

  In such a drawing unit 2, the electron beam B is emitted from the emission unit 21, and is irradiated to the first shaping aperture 23 by the illumination lens 22. The first shaping aperture 23 has, for example, a rectangular opening. Thereby, when the electron beam B passes through the first shaping aperture 23, the cross-sectional shape of the electron beam is shaped into a rectangular shape and projected onto the second shaping aperture 26 by the projection lens 24. The projection position can be deflected by the shaping deflector 25, and the shape and size of the electron beam B can be controlled by changing the projection position. Thereafter, the electron beam B that has passed through the second shaping aperture 26 is irradiated with the focus of the electron beam B being adjusted to the sample W on the stage 11 by the objective lens 27. At this time, the shot position of the electron beam B with respect to the sample W on the stage 11 is changed by the sub deflector 28 and the main deflector 29.

  The control unit 3 includes a drawing data storage unit 3 a that stores drawing data, a shot data generation unit 3 b that processes the drawing data to generate shot data, and a drawing control unit 3 c that controls the drawing unit 2. Yes. The shot data generation unit 3b and the drawing control unit 3c may be configured by hardware such as an electric circuit, may be configured by software such as a program that executes each function, or may be You may comprise by the combination of both.

  The drawing data storage unit 3 a is a storage unit that stores drawing data for drawing a pattern on the sample W. The drawing data is converted into a format for the charged particle beam drawing apparatus 1 so that design data (layout data) created by a semiconductor integrated circuit designer can be input to the charged particle beam drawing apparatus 1. The data is input from an external device to the drawing data storage unit 3a and stored. For example, a magnetic disk device, a semiconductor disk device (flash memory), or the like can be used as the drawing data storage unit 3a.

  The design data described above usually includes a large number of minute patterns (such as graphics), and the amount of data is considerably large. If this design data is converted into another format as it is, the data amount after conversion further increases. For this reason, in the drawing data, the amount of data is reduced by a method such as data hierarchization or pattern array display. Such drawing data is data that defines a drawing pattern of a chip area or a drawing pattern of a virtual chip area that is virtually merged into a plurality of chip areas that have the same drawing conditions. .

  The shot data generation unit 3b divides the drawing pattern defined by the drawing data into a plurality of stripe regions (stripes) (a longitudinal direction is the X direction and a short direction is the Y direction), and Each stripe region is divided into a large number of matrix-like subregions. In addition, the shot data generation unit 3b determines the shape, size, position, and the like of the figure in each sub-area, and if the figure cannot be drawn in one shot, a plurality of drawables Is divided into partial areas, and shot data is generated. The length of the stripe region in the short direction (Y direction) is set to a length capable of deflecting the electron beam B by main deflection.

  When drawing the above-mentioned drawing pattern, the drawing control unit 3c moves the stage 11 in the longitudinal direction (X direction) of the stripe region, positions the electron beam B in each sub region by the main deflector 29, and performs sub deflection. A graphic is drawn by shooting at a predetermined position in the sub-region by the device 28. After that, when drawing of one stripe region is completed, the stage 11 is moved stepwise in the Y direction, and then the next stripe region is drawn. This is repeated, and drawing by the electron beam B is performed on the entire drawing region of the sample W. Do. During drawing, since the stage 11 continuously moves in one direction, the drawing origin of the sub-region is tracked by the main deflector 29 so that the drawing origin follows the movement of the stage 11. .

  Thus, the irradiation position of the electron beam B is determined while following the stage 11 which is deflected by the sub deflector 28 and the main deflector 29 and continuously moves. The drawing time can be shortened by continuously moving the stage 11 in the X direction and making the shot position of the electron beam B follow the movement of the stage 11. However, in the first embodiment, the stage 11 is continuously moved in the X direction. However, the present invention is not limited to this. For example, one sub-region is drawn while the stage 11 is stopped. When moving to the next sub-region, a step-and-repeat drawing method that does not perform drawing may be used.

  In such drawing with the electron beam B, the relative distance information related to the relative distance from the stage 11 measured by the laser interferometer 12 is not only the control (feedback control) related to the movement of the stage 11 but also the sub deflector 28 and the main deflector. It is also used for the control of the deflector 29, that is, the irradiation position control (drawing control).

  Next, the laser interferometer 12 will be described in detail.

  As shown in FIG. 2, two laser interferometers 12 are provided, and the first laser interferometer 12 positioned on the lower side in FIG. 2 includes the stage 11 in the Y direction that is the moving direction of the stage 11. Relative distance (Y-direction relative distance) is measured. Further, the second laser interferometer 12 located on the left side in FIG. 2 measures a relative distance (relative distance in the X direction) from the stage 11 in the X direction, which is the moving direction of the stage 11. Since these first and second laser interferometers 12 have the same structure, the common structure will be described below.

  As shown in FIGS. 2 and 3, the laser interferometer 12 includes a light projecting unit 12a that projects laser light, a light receiving unit 12b that receives laser light, and a polarization beam splitter (which separates the deflection components of the laser light). PBS) 12c, a reflecting portion 12d that reflects laser light, a λ / 4 plate 12e that functions as a phase plate that gives a phase difference of π / 2, and a fixed mirror 12f that functions as a reflecting mirror that reflects laser light. I have. The polarizing beam splitter 12c, the reflecting portion 12d, the λ / 4 plate 12e, and the fixed mirror 12f are various optical components.

  The light projecting unit 12a and the light receiving unit 12b are provided on the outer periphery of the drawing chamber 2a (see FIG. 2). As the light receiving portion 12b, for example, a CCD (charge coupled device) or the like can be used. In addition, in order to take out interference light to the light-receiving part 12b, optical components (not shown), such as a corner cube prism and a λ / 4 plate, are provided as necessary.

  The polarization beam splitter 12c is provided in a storage chamber R formed on the side surface of the drawing chamber 2a. The polarization beam splitter 12c has a polarization separation surface M1 (see FIG. 3) that separates the laser light into measurement light (length measurement light) L1 and reference light L2, and reflects the laser light toward the stage 11 and the measurement light L1. This is a beam splitter that splits the beam into reference light L2 that travels toward the section 12d. The polarization beam splitter 12c is formed in a rectangular parallelepiped shape from a material such as glass, for example.

  The polarizing beam splitter 12c is provided on the upper surface of a base body (not shown) provided on the bottom surface of the storage chamber R via an adhesive layer. The base body is fixed to the bottom surface of the storage chamber R by a fixing member (not shown) such as a bolt or an adhesive. The base body is made of a metal such as an iron-nickel alloy so that the coefficient of thermal expansion is low. In particular, the thermal expansion coefficient of the base body is a thermal expansion coefficient that does not cause distortion to the polarization beam splitter 12c due to the expansion.

  Further, the above-described storage chamber R is formed so that the laser beam deflected by the polarization beam splitter 12c can travel toward the stage 11, that is, the internal space of the storage chamber R is connected to the internal space of the drawing chamber 2a. (See FIG. 2). Further, a part of the wall surface of the storage chamber R is formed so that the laser beam emitted from the light projecting unit 12a and the laser beam received by the light receiving unit 12b are transmitted. The accommodation room R functions as a part of the drawing room 2a.

  The reflection unit 12d has a reflection surface M2 (see FIG. 3) parallel to the polarization separation surface M1 of the polarization beam splitter 12c, and the reference light L2 separated by the polarization beam splitter 12c is fixed in parallel to the measurement light L1. Reflect towards As the reflecting portion 12d, for example, a rectangular parallelepiped reflecting mirror can be used. Furthermore, the reflecting portion 12d is formed smaller than the polarizing beam splitter 12c, and is fixed to the side surface of the polarizing beam splitter 12c. As this fixing method, for example, a bonding method for directly bonding the reflecting portion 12d and the polarizing beam splitter 12c, a bonding method using an adhesive having light transmittance, or the like can be used.

  Here, the weight of the reflecting portion 12d is desirably a weight that does not cause distortion (twist) of the polarizing beam splitter 12c, and is preferably 10% or less of the weight of the polarizing beam splitter 12c, for example. This is because when the weight of the reflecting portion 12d is greater than 10% of the weight of the polarizing beam splitter 12c, the weight causes the distortion of the polarizing beam splitter 12c, and the optical performance of the polarizing beam splitter 12c, that is, the separation performance decreases. Because.

  The λ / 4 plate 12e and the fixed mirror 12f are arranged in that order in the traveling direction of the incoming laser beam, and are fixed to the wall surface of the drawing chamber 2a, that is, the wall surface of the chamber that is the housing (see FIG. 2). As this fixing method, for example, a fixing method using a fixing member such as an adhesive or an attachment member can be used. The drawing chamber 2a is firmly fixed so as not to vibrate.

  As described above, the λ / 4 plate 12e and the fixed mirror 12f are provided on the wall surface (the wall surface of the chamber) of the drawing chamber 2a in a firmly fixed state by a fixing member, an attachment member, or the like, and are in a fixed state that does not vibrate. At this time, even when the λ / 4 plate 12e and the fixed mirror 12f are fixed by the mounting member so as not to vibrate, there is almost no restriction such as temperature distortion between the fixed mirror 12f and the mounting member in the design of the fixed mirror 12f (temperature Since distortion hardly affects the reflection performance), the design can be performed easily.

  Here, on the side surface of the stage 11, a mirror 11a that functions as a reflecting mirror that reflects laser light is attached. The mirror 11a is fixed to the side surfaces of the stage 11 on the first and second laser interferometers 12 side, and the laser beams emitted from the first and second laser interferometers 12 are respectively applied to the first and second laser interferometers 12. Reflected toward the laser interferometer 12.

  In such a laser interferometer 12, as shown in FIG. 3, the laser light emitted from the light projecting unit 12a is separated (divided) by the polarization beam splitter 12c, and measurement light which is one of the separated laser lights. L1 goes straight toward the stage 11. On the other hand, the reference light L2, which is the other of the separated laser lights, travels straight toward the reflecting portion 12d. Thereafter, the reference light L2 is reflected at a right angle by the reflecting portion 12d and travels straight toward the λ / 4 plate 12e and the fixed mirror 12f in parallel with the measurement light L1.

  These laser beams are reflected by the mirror 11a of the stage 11, or the fixed mirror 12f and the reflecting part 12d, return to the polarizing beam splitter 12c, and are superimposed by the polarizing beam splitter 12c to interfere with each other. The interfering laser light (interference light) is received by the light receiving unit 12b, and interference fringes generated by the optical path difference are observed. Such measurement is performed in both the X direction and the Y direction, the relative distance in the Y direction between the first laser interferometer 12 and the stage 11, and the X direction between the second laser interferometer 12 and the stage 11. The relative distance is measured, and the position of the stage 11 is grasped from the relative distance information.

  In the first embodiment, the 1 (single) -pass laser interferometer 12 is used as described above, but the present invention is not limited to this. For example, a 2 (double) path laser interferometer that reciprocates the laser beam to and from the object to be measured may be used, or 4 (four) that reciprocates the laser light to and from the object to be measured. A path type laser interferometer may be used, and the number of paths is not particularly limited. Further, as the optical component, the polarizing beam splitter 12c, the reflecting portion 12d, the λ / 4 plate 12e, and the fixed mirror 12f are used. However, various types of beam splitters, phase plates, and the like can be used. Furthermore, the number of members can be increased.

  As described above, in the charged particle beam drawing apparatus 1 described above, the reflection portion 12d that reflects the reference light L2 separated by the polarization beam splitter 12c in parallel to the measurement light L1 is provided on the side surface of the polarization beam splitter 12c. A fixed mirror 12f that reflects the reference light L2 reflected by the reflecting portion 12d toward the reflecting portion 12d in parallel to the measurement light L1 is provided on the wall surface of the drawing chamber 2a together with the λ / 4 plate 12e.

  Here, when mechanical vibration is generated by a motor for moving the stage 11 or a vacuum pump for evacuation, the polarization beam splitter 12c may vibrate in the lateral direction, that is, in the optical path direction of the measurement light L1. is there. At this time, for example, when the polarization beam splitter 12c vibrates in the Y direction in the first laser interferometer 12 in which the optical path direction of the measurement light L1 is the Y direction, the optical path length of the reference light L2 (= the optical path in the X direction) Both the optical path length in the length + Y direction) and the optical path length in the measuring light L1 (optical path length in the Y direction) vary by the same amount in the Y direction. Even when the polarization beam splitter 12c vibrates in the X direction in the second laser interferometer 12 in which the optical path direction of the measurement light L1 is the X direction, the optical path length of the reference light L2 (= the optical path length in the Y direction + the X direction) And the optical path length of the measurement light L1 (the optical path length in the X direction) both vary by the same amount in the X direction.

  Therefore, when the reflecting portion 12d is provided on the side surface of the polarizing beam splitter 12c and the fixed mirror 12f is provided corresponding to the reflecting portion 12d, the polarizing beam splitter 12c vibrates in the optical path direction of the measuring light L1. Then, the optical path length variation occurs in both the measurement light L1 and the reference light L2. However, since the optical path of the measurement light L1 separated by the polarization beam splitter 12c and the optical path of the reference light L2 separated by the polarization beam splitter 12c and reflected by the reflecting portion 12d are parallel, the measurement light caused by the vibration described above. The variation amounts of the optical path lengths of L1 and reference light L2 are the same. Thereby, the vibration described above does not affect the optical path difference between the measurement light L1 and the reference light L2, that is, the measurement light L1 and the reference light L2 are caused by the vibration of the polarization beam splitter 12c in the optical path direction of the measurement light L1. Therefore, it is possible to prevent the above-described fluctuation in the optical path length from being a measurement error as it is. As described above, it is possible to suppress the measurement accuracy of the laser interferometer 12 from being lowered due to the vibration of the polarization beam splitter 12c, and thus it is possible to suppress a reduction in drawing accuracy.

  On the other hand, as shown in FIG. 4, the fixed mirror 12f may be provided directly on the side surface of the polarization beam splitter 12c together with the λ / 4 plate 12e (the comparative example described above). At this time, when the polarization beam splitter 12c vibrates in the Y direction in the first laser interferometer 12 in which the optical path direction of the measurement light L1 is the Y direction, the optical path length of the reference light L2 (the optical path length in the X direction) is Only the optical path length of the measurement light L1 (the optical path length in the Y direction) varies in the Y direction without variation. When the polarization beam splitter 12c vibrates in the X direction in the second laser interferometer 12 in which the optical path direction of the measurement light L1 is the X direction, the optical path length (optical path length in the Y direction) of the reference light L2 varies. Instead, only the optical path length of the measurement light L1 (the optical path length in the X direction) varies in the X direction.

  Therefore, when the fixed mirror 12f is provided directly on the side surface of the polarization beam splitter 12c together with the λ / 4 plate 12e, the optical path length of the measurement light L1 when the polarization beam splitter 12c vibrates in the optical path direction of the measurement light L1. Only fluctuates. That is, the optical path difference between the measurement light L1 and the reference light L2 changes due to the vibration of the polarization beam splitter 12c in the optical path direction of the measurement light L1, and the change in the optical path length of the measurement light L1 is directly caused by a measurement error. turn into. Thus, since the measurement accuracy of the laser interferometer 12 is lowered by the vibration of the polarization beam splitter 12c, the drawing accuracy is lowered.

  As described above, according to the first embodiment, the reflection part 12d that reflects the reference light L2 separated by the polarization beam splitter 12c in parallel to the measurement light L1, and the reference light reflected by the reflection part 12d. Even if the polarizing beam splitter 12c vibrates in the optical path direction of the measurement light L1 by providing the fixed mirror 12f that reflects L2 toward the reflecting portion 12d in parallel with the measurement light L1, the measurement light L1 and the reference due to the vibration even if the polarization beam splitter 12c vibrates in the optical path direction of the measurement light L1. The amount of variation in the optical path lengths of the light L2 is the same. As a result, the optical path difference between the measurement light L1 and the reference light L2 is not changed by the vibration of the polarization beam splitter 12c in the optical path direction of the measurement light L1, thereby preventing a measurement error due to the vibration from occurring. Is possible. Therefore, it is possible to prevent the measurement accuracy of the laser interferometer 12 from being lowered due to the vibration of the polarization beam splitter 12c, and as a result, it is possible to suppress a reduction in apparatus accuracy, that is, drawing accuracy.

  In addition, since the polarizing beam splitter 12c is not firmly fixed by a mounting member or the like, a strong external force is not applied to the polarizing beam splitter 12c, and the generation of distortion of the polarizing beam splitter 12c can be prevented. Furthermore, it is possible to prevent the polarization beam splitter 12c from being distorted due to thermal expansion or contraction of the mounting member. Therefore, it is possible to suppress a decrease in the optical performance of the polarization beam splitter 12c, that is, the separation performance and to prevent a decrease in measurement accuracy of the laser interferometer 12, so that a decrease in drawing accuracy can be further suppressed.

  Further, by using the relative distance information measured by the laser interferometer 12 with respect to the relative distance to the stage 11 for controlling the sub deflector 28 and the main deflector 29, that is, for controlling the irradiation position (drawing control), it is possible to accurately Therefore, the drawing accuracy can be improved. When the relative distance information used for such drawing control is affected by vibration, the drawing accuracy is significantly reduced. However, as described above, it is possible to suppress the decrease in measurement accuracy of the laser interferometer 12 due to vibration. As a result, it is possible to suppress a significant decrease in drawing accuracy.

  In addition, the reflecting portion 12d is provided on the side surface of the polarizing beam splitter 12c. As a result, the reflecting portion 12d and the polarization beam splitter 12c can be integrated after being manufactured separately, which facilitates the manufacturing. Specifically, it is only necessary to attach the reflecting portion 12d to the outer surface of the polarizing beam splitter 12c, and it is not necessary to process the polarizing beam splitter 12c in order to integrate the reflecting portion 12d and the polarizing beam splitter 12c. As a result, manufacturing can be facilitated, and further, degradation of the separation performance of the polarization beam splitter 12c due to processing can be prevented.

  Furthermore, when the reflecting part 12d is provided on the side surface of the polarizing beam splitter 12c as described above, it is desirable that the weight of the reflecting part 12d is 10% or less of the weight of the polarizing beam splitter 12c. In this case, distortion (twist) of the polarization beam splitter 12c is less likely to occur due to the weight of the reflecting portion 12d provided on the side surface of the polarization beam splitter 12c, and the separation performance of the polarization beam splitter 12c is more favorably maintained. Is possible. For this reason, it is possible to more reliably suppress a decrease in measurement accuracy of the laser interferometer 12 and prevent a decrease in drawing accuracy.

  A fixed mirror 12f is fixed to the wall of the drawing chamber 2a in a fixed state. As a result, since the drawing chamber 2a is firmly fixed, even when a disturbance vibration occurs such that the polarization beam splitter 12c vibrates in the optical path direction of the measurement light L1, the vibration of the fixed mirror 12f due to the disturbance vibration is suppressed. It is possible. Therefore, it is possible to suppress the measurement accuracy of the laser interferometer 12 from being lowered due to the vibration, and as a result, it is possible to suppress a decrease in drawing accuracy.

(Second Embodiment)
A second embodiment will be described with reference to FIG.

  In the second embodiment, differences from the first embodiment will be described, the same parts as those described in the first embodiment will be denoted by the same reference numerals, and the description thereof will also be omitted.

  As shown in FIG. 5, the pattern inspection apparatus 51 according to the second embodiment includes an inspection unit 52 that inspects a pattern and an inspection control unit 53 that controls the inspection unit 52. The inspection control unit 53 may be configured by hardware such as an electric circuit, may be configured by software such as a program that executes each function, or is configured by a combination of both. May be.

  The inspection unit 52 includes an imaging unit 52a such as an inspection camera in addition to the stage 11 and the laser interferometer 12 according to the first embodiment. The imaging unit 52a is provided so that the sample W on the stage 11 can be imaged.

  The inspection control unit 53 acquires relative distance information regarding the relative distance (relative distance in the X direction and the Y direction) with the stage 11 measured by the laser interferometer 12, and from the position of the stage 11 based on the relative position information, Image position information (coordinate information) when an image is captured by the imaging unit 52a is obtained. Therefore, the relative distance information related to the relative distance from the stage 11 measured by the laser interferometer 12 is not only the control (feedback control) related to the movement of the stage 11 but also the relative position between the imaging unit 52 a and the stage 11, that is, the captured image. It is also used to acquire image position information.

  The inspection unit 52 receives, for example, inspection apparatus data that is first data obtained by converting layout data (design data, CAD data, etc.) of a semiconductor integrated circuit or the like. In addition, the inspection unit 52 receives data for inspection apparatus, which is second data created based on a pattern actually drawn on the sample W by the charged particle beam drawing apparatus 1 according to the first embodiment. The

  The inspection device data, which is the first data, is input to the inspection unit 52 from a storage device (not shown) such as a database for storing the data via a wired or wireless network. Similarly, the inspection device data as the second data is also input to the inspection unit 52 via a wired or wireless network from a storage device (not shown) such as a database for storing the data. Note that these inspection device data are hierarchized, for example, similarly to the drawing data according to the first embodiment.

  The inspection unit 52 inspects the pattern actually drawn on the sample W by the charged particle beam drawing apparatus 1 according to the first embodiment, using the input data for each inspection apparatus. In this inspection, for example, an inspection such as comparing an actually drawn pattern with drawing data is performed. At this time, the above-described image position information (coordinate information) is used for pattern position inspection.

  In the laser interferometer 12 of the present embodiment as well, for the same reason as in the first embodiment, the weight of the reflecting portion 12d is desirably 10% or less of the weight of the polarizing beam splitter 12c.

  As described above, according to the second embodiment, the same effects as those of the first embodiment can be obtained. That is, in the pattern inspection apparatus 51, even if the polarization beam splitter 12c vibrates in the optical path direction of the measurement light L1, the amount of variation in the optical path lengths of the measurement light L1 and the reference light L2 due to the vibration is the same. As a result, the optical path difference between the measurement light L1 and the reference light L2 is not changed by the vibration of the polarization beam splitter 12c in the optical path direction of the measurement light L1, so that it is possible to prevent a measurement error due to the vibration from occurring. It becomes possible. Therefore, it is possible to prevent the measurement accuracy of the laser interferometer 12 from being lowered due to the vibration of the polarization beam splitter 12c, and as a result, it is possible to suppress a decrease in apparatus accuracy, that is, inspection accuracy.

  Further, by using the relative distance information related to the relative distance from the stage 11 measured by the laser interferometer 12 for obtaining the image position information of the imaging unit 52a, an accurate inspection can be performed, thereby improving the inspection accuracy. can do. When the image position information used for such inspection is affected by vibration, the inspection accuracy is remarkably reduced. However, as described above, it is possible to suppress a decrease in measurement accuracy of the laser interferometer 12 due to vibration. As a result, a significant decrease in inspection accuracy can be suppressed.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Charged particle beam drawing apparatus 2 Drawing part 2a Drawing room 2b Optical barrel 3 Control part 3a Drawing data storage part 3b Shot data generation part 3c Drawing control part 11 Stage 11a Mirror 12 Laser interferometer 12a Light projection part 12b Light receiving part 12c Polarization Beam splitter 12d Reflector 12e λ / 4 plate 12f Fixed mirror 21 Emitter 22 Illumination lens 23 First shaping aperture 24 Projection lens 25 Molding deflector 26 Second shaping aperture 27 Objective lens 28 Sub deflector 29 Main deflector 51 Pattern inspection device 52 Inspection unit 52a Imaging unit 53 Inspection control unit B Electron beam L1 Measurement light L2 Reference light W Sample

Claims (5)

A movable stage that supports the sample;
A laser interferometer that measures a relative distance from the stage in the moving direction of the stage with a laser beam;
With
The laser interferometer is
A beam splitter for separating the laser light into measurement light and reference light;
A reflection unit configured to reflect the reference light separated by the beam splitter in parallel with the measurement light;
A fixed mirror that reflects the reference light reflected by the reflecting portion toward the reflecting portion in parallel with the measurement light;
A charged particle beam drawing apparatus comprising:   The charged particle beam drawing apparatus according to claim 1, wherein the reflection unit is provided on a side surface of the beam splitter.   3. The charged particle beam drawing apparatus according to claim 2, wherein the weight of the reflecting portion is 10% or less of the weight of the beam splitter. It further comprises a fixed drawing chamber that houses the stage,
The charged particle beam drawing apparatus according to any one of claims 1 to 3, wherein the fixed mirror is fixed to a wall of the drawing chamber. A movable stage that supports the sample;
A laser interferometer that measures a relative distance from the stage in the moving direction of the stage with a laser beam;
With
The laser interferometer is
A beam splitter for separating the laser light into measurement light and reference light;
A reflection unit configured to reflect the reference light separated by the beam splitter in parallel with the measurement light;
A fixed mirror that reflects the reference light reflected by the reflecting portion toward the reflecting portion in parallel with the measurement light;
A pattern inspection apparatus comprising:

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