JP7219660B2 - Charged particle beam writer and aperture - Google Patents

Description

The present invention relates to a charged particle beam writing apparatus and aperture.

2. Description of the Related Art As semiconductor devices become more highly integrated, circuit patterns of semiconductor devices are becoming finer. A lithographic technique for forming a circuit pattern on a semiconductor substrate is important for achieving miniaturization of circuit patterns. A highly accurate original image pattern (also called a reticle or mask) is required to form a fine circuit pattern using the lithography technique. Electron beam writing inherently has excellent resolution and is used to produce high-precision original patterns.

In electron beam writing, an aperture that partially blocks the electron beam is used to shape the electron beam that irradiates the sample. In order to improve the electron beam shaping accuracy, the thickness of the aperture is reduced to improve the processing accuracy of the edge of the opening of the aperture.

However, reducing the thickness of the aperture increases the amount of electrons that pass through the aperture. Electrons that have passed through the aperture are scattered and irradiate a member such as a deflector to cause burn-in of impurities. For example, if impurities stick to the deflector, electrons are charged up in the portion where the impurities stick. When the electrons are charged up in the deflector, the electron beam drifts, resulting in deterioration of positional accuracy of writing.

Patent Document 1 discloses a technique of reducing the amount of electrons passing through the aperture by using an aperture in which a second member having a higher electron beam shielding capability than the first member is laminated on the first member. ing.

JP 2013-120943 A

A problem to be solved by the present invention is to provide a charged particle beam drawing apparatus and an aperture that can reduce the amount of electrons that pass through the aperture.

A charged particle beam writing apparatus according to one aspect of the present invention includes an irradiation unit that emits a charged particle beam to irradiate a sample, a stage on which the sample can be placed, a first portion having a first opening, a second portion fixed to the stage side of the first portion and having a second opening, wherein a portion of the second portion on the irradiation section side is the first portion; The distance between the inner end of the first opening and the second portion is larger than the thickness of the inner end of the first opening of the first portion, and the light is emitted from the irradiation section. and an aperture for shaping the charged particle beam ,
The diameter of the second opening on the side of the first portion is larger than the diameter of the first opening, and the diameter of the second opening on the side opposite to the side of the first portion is larger than the diameter of the first opening. 2, the diameter of the opening is larger than the diameter of the first opening, and the diameter of the second opening between the side of the first portion and the side opposite to the side of the first portion is larger than the diameter of the first opening. , .

In the charged particle beam drawing apparatus of the aspect described above, it is preferable that the interval is 100 μm or more.

In the charged particle beam drawing apparatus of the aspect described above, it is preferable that the charged particle beam transmittance of the second portion is lower than the charged particle beam transmittance of the first portion.

In the charged particle beam writing apparatus of the aspect described above, it is preferable that the diameter of the second opening is larger than the diameter of the first opening.

An aperture according to one aspect of the present invention has a first portion having a first opening and a second portion fixed to the first portion and having a second opening, and the second portion A portion of the surface of the portion facing the first portion is spaced apart from the first portion, and the thickness of the inner end portion of the first opening of the first portion is greater than the thickness of the first opening. and the second portion of the aperture for shaping the charged particle beam.

According to the present invention, it is possible to provide a charged particle beam writing apparatus and aperture capable of reducing the amount of electrons that pass through the aperture.

1 is a conceptual diagram showing the configuration of a charged particle beam writing apparatus according to a first embodiment; FIG. FIG. 4 is an explanatory diagram of the operation of variable shaping type electronic writing according to the first embodiment; FIG. 4 is a schematic diagram showing the structure of an aperture according to the first embodiment; FIG. 4 is an explanatory diagram of problems when using the aperture of the first comparative form; Explanatory drawing of the function and effect of the aperture of 1st Embodiment. FIG. 10 is an explanatory diagram of a problem when using the aperture of the second comparative form; 4 is a table showing the effect of the aperture of the first embodiment; FIG. 5 is a schematic diagram showing the structure of an aperture according to the second embodiment; FIG. 8 is a schematic diagram showing the structure of an aperture according to the third embodiment; FIG. 10 is a schematic diagram showing the structure of an aperture according to the fourth embodiment; FIG. 11 is an enlarged schematic cross-sectional view of an aperture according to a fourth embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a configuration using an electron beam as an example of a charged particle beam will be described. However, the charged particle beam is not limited to an electron beam, and may be a beam using charged particles such as an ion beam.

In this specification, drawing data is base data of a pattern to be drawn on a sample. The drawing data is data obtained by converting the format of design data generated by a designer using CAD or the like so as to enable arithmetic processing in the drawing apparatus. A drawing pattern such as a figure is defined by, for example, the coordinates of the vertices of the figure.

(First embodiment)
A charged particle beam writing apparatus according to the first embodiment includes an irradiation unit that emits a charged particle beam to irradiate a sample, a stage on which the sample can be placed, a first portion having a first opening, a first a second portion fixed to the stage side with respect to the first portion and having a second opening; a portion between the first portion and the second portion is spaced apart; The edge of the opening is recessed with respect to the edge of the first opening, and the distance between the first portion and the second portion is greater than the thickness of the edge of the first opening of the first portion. , an aperture for shaping the charged particle beam that impinges on the specimen.

Also, the aperture for shaping the charged particle beam of the first embodiment includes a first portion having a first opening and a second portion fixed to the first portion and having a second opening. a portion between the first portion and the second portion is spaced apart and the end of the second opening of the first portion is recessed relative to the end of the first opening; The distance between the first portion and the second portion is greater than the thickness of the end portion of the first opening.

The charged particle beam drawing apparatus and aperture of the first embodiment can reduce the amount of electrons that pass through the aperture by having the above configuration. Therefore, for example, characteristic fluctuations of the charged particle beam writing apparatus, such as drift of the charged particle beam, are suppressed.

A case where the charged particle beam drawing apparatus is a mask drawing apparatus will be described below as an example.

FIG. 1 is a conceptual diagram showing the configuration of a charged particle beam writing apparatus according to the first embodiment.

In FIG. 1 , the mask drawing apparatus 100 (charged particle beam drawing apparatus) includes a drawing section 150 and a control section 160 . Mask drawing apparatus 100 is an example of a charged particle beam drawing apparatus. A mask drawing apparatus 100 draws a desired pattern on a sample 101 .

The drawing unit 150 has an electron barrel 102 and a drawing chamber 103 . Inside the electron lens barrel 102 are an electron gun 201 (irradiation unit), an illumination lens 202, a blanking deflector 212, a blanking aperture 214, a first aperture 203, a projection lens 204, a deflector 205, and a second aperture 206. (aperture), an objective lens 207 and a deflector 208 are arranged.

Also, an XY stage 105 (stage) that is movably arranged is arranged in the writing chamber 103 . A sample 101 can be placed on the XY stage 105 . The sample 101 is, for example, an exposure mask substrate for transferring a pattern onto a wafer. The mask substrate is, for example, mask blanks on which nothing is drawn yet.

The control unit 160 includes the drive circuit 108, the magnetic disk device 109, the deflection control circuit 110, the digital-analog converter 112 (DAC), the digital-analog converter 114 (DAC), the digital-analog converter 116 (DAC), the control computer 120, and a memory 121 .

Drawing data stored in the magnetic disk device 109 is input to the control computer 120 . Information input to the control computer 120 , information being processed, and information after being processed are stored in the memory 121 , for example.

A memory 121, a deflection control circuit 110, and a magnetic disk device 109 are connected to the control computer 120 via a bus (not shown). Deflection control circuit 110 is connected to DAC 112 , DAC 114 , and DAC 116 . DAC 112 is connected to blanking deflector 212 . DAC 114 is connected to deflector 205 . DAC 116 is connected to deflector 208 .

In FIG. 1, constituent parts necessary for explaining the first embodiment are described. Needless to say, the mask drawing apparatus 100 generally includes other necessary configurations.

FIG. 2 is an explanatory diagram of the operation of the variable shaping type electronic drawing of the first embodiment. Hereinafter, a drawing method by the mask drawing apparatus 100 will be described with reference to FIGS. 1 and 2. FIG.

An electron beam 200 is emitted from an electron gun 201 . The electron gun 201 is an example of an irradiation unit. An electron beam 200 emitted from an electron gun 201 illuminates the entire first aperture 203 through an illumination lens 202 .

An opening 411 for shaping the electron beam 200 is formed in the first aperture 203 . The shape of the opening 421 is, for example, rectangular as shown in FIG. A first aperture 203 shapes the electron beam 200 into a rectangle.

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 second aperture 206 has an opening 421 for shaping the electron beam 200 passing through the opening 411 into a desired shape. The shape of the opening 421 is not particularly limited. For example, as shown in FIG. 2, it may be rectangular. Also, for example, polygons other than rectangles may be used. Further, for example, the shape may be a combination of a plurality of polygons.

The position of the first aperture image on the second aperture 206 is deflection controlled by a deflector 205 (FIG. 1). It can then pass through a predetermined portion of aperture 421 to change the beam shape and size. As a result, the electron beam 200 is shaped.

The second aperture image electron beam 200 passing through the second aperture 206 is focused by the objective lens 207 (FIG. 1) and deflected by the deflector 208 . As a result, the electron beam 200 is irradiated onto a desired position of the sample 101 on the continuously moving XY stage 105 .

Movement of the XY stage 105 is driven by a drive circuit 108 . The deflection voltage of deflector 205 is controlled by deflection control circuit 110 and DAC 114 . The deflection voltage of deflector 208 is controlled by deflection control circuit 110 and DAC 116 .

The shape of the electron beam that can pass through both the aperture 411 and the aperture 421 is drawn on the drawing area of the sample 101 . A method of forming an arbitrary shape by passing through both the openings 411 and 421 as described above is called a variable molding method.

When the electron beam 200 on the sample 101 has reached the irradiation time t at which a desired irradiation dose is incident on the sample 101, blanking is performed as follows. That is, in order to prevent the electron beam 200 from being irradiated onto the sample 101 more than necessary, the electron beam 200 is deflected by, for example, an electrostatic blanking deflector 212 and cut by a blanking aperture 214 . This prevents the electron beam 200 from reaching the surface of the sample 101 . The deflection voltage of blanking deflector 212 is controlled by deflection control circuit 110 and DAC 112 .

When the beam is ON (blanking OFF), the electron beam 200 emitted from the electron gun 201 follows the trajectory indicated by the solid line in FIG. On the other hand, when the beam is OFF (blanking ON), the electron beam 200 emitted from the electron gun 201 follows the trajectory indicated by the dotted line in FIG.

Further, the inside of the electron column 102 and the inside of the writing chamber 103 are evacuated by a vacuum pump (not shown) to a pressure lower than the atmospheric pressure.

FIG. 3 is a schematic diagram showing the structure of the aperture of the first embodiment. FIG. 3(a) is a top view, and FIG. 3(b) is a cross-sectional view taken along line AA' of FIG. 3(a).

In the first embodiment, for example, the aperture 10 of FIG. 3 is applied to the second aperture 206 of FIGS.

Aperture 10 has a laminated structure of first portion 11 and second portion 12 . The first portion 11 has a first opening 21 and the second portion 12 has a second opening 22 . The shape of the first opening 21 and the second opening 22 is a combination of a rectangle and a hexagon.

The second portion 12 is located on the XY stage 105 side with respect to the first portion 11 . The second portion 12 is fixed to the XY stage 105 side with respect to the first portion 11 . The first portion 11 is located on the electron gun 201 side with respect to the second portion 12 .

The upper surface of the first portion 11 is irradiated with an electron beam. An electron beam passes through the first opening 21 and the second opening 22 to shape the electron beam.

The second portion 12 has the function of shielding part of the electrons that have passed through the first portion 11 .

The first portion 11 and the second portion 12 are made of, for example, the same material. The first portion 11 and the second portion 12 are made of silicon, for example.

By using silicon as the material, existing semiconductor processes can be applied during processing. Also, the amount of impurities can be kept low. However, semiconductors such as, for example, silicon nitride, silicon carbide, silicon germanide, and metals or metal compounds can also be used as materials.

The first portion 11 and the second portion 12 are bonded together using, for example, an adhesive layer. The first portion 11 and the second portion 12 may be integrally molded.

When the first portion 11 and the second portion 12 are made of silicon, the thickness t1 of the end portion E1 of the first opening 21 of the first portion 11 is, for example, 1 μm or more and 10 μm or less. The thickness t2 of the end E2 of the second opening 22 of the second portion 12 is, for example, 10 μm or more and 100 μm or less.

The electron beam transmittance of the second portion 12 is smaller than the electron beam transmittance of the first portion 11 . In other words, the amount of electrons transmitted through the second portion 12 is less than the amount of electrons transmitted through the first portion 11 when the same energy and the same amount of electrons are irradiated. The thickness t2 of the second portion 12 is greater than the thickness t1 of the first portion 11 when the first portion 11 and the second portion 12 are of the same material.

As shown in FIG. 3 , the position of the end E2 of the second opening 22 of the second portion 12 is the first position relative to the position of the end E1 of the first opening 21 of the first portion 11 . retreating in the direction of In other words, the diameter of the second opening 22 is larger than the diameter of the first opening 21 . For example, the second opening 22 surrounds the first opening 21 when viewed from above the aperture 10 . For example, the first portion 11 and the second portion 12 are laminated such that the end E1 of the first opening 21 and the end E2 of the second opening 22 do not overlap.

A receding amount d1 of the end E2 of the second opening 22 from the end E1 of the first opening 21 is, for example, 0.5 μm or more and 10 μm or less.

As shown in FIG. 3, a portion between the first portion 11 and the second portion 12 is separated. A portion of the second portion 12 on the electron gun 201 (irradiating portion) side is separated from the first portion 11 . A portion of the surface of the second portion 12 facing the first portion 11 is separated from the first portion 11 . A gap is provided between the first portion 11 and the second portion 12 . Some of the electrons transmitted through the first portion 11 are confined within the air gap to reduce the amount of electrons transmitted through the aperture 10 .

A distance d2 between the first portion 11 and the second portion 12 is larger than the thickness t1 of the end E1 of the first opening 21 of the first portion 11 . A distance d2 between the inner end of the first opening 21 and the second portion 12 is larger than the thickness of the inner end of the first opening 21 of the first portion 11 . The interval d2 is, for example, 50 μm or more and 5 mm or less.

The inner end of the first opening 21 means the end of the first portion 11 on the first opening 21 side. The inner end of the first opening 21 corresponds to the end E1 of the first opening 21 . Also, the inner end portion of the first opening 21 of the first portion 11 means the first portion 11 near the inner end of the first opening 21 .

When the direction in which the end E2 of the second opening 22 retreats with respect to the end E1 of the first opening 21 is defined as the first direction, from the end E2 of the second opening 22 to the first The minimum value of the distance dx in the first direction to the portion 11 of is, for example, greater than half the distance d2 between the first portion 11 and the second portion 12 and less than twice. The minimum value of the distance dx is, for example, 25 μm or more and 1 mm or less.

Actions and effects of the charged particle beam drawing apparatus and the aperture of the first embodiment will be described below.

In electron beam writing, an aperture that partially blocks the electron beam is used to shape the electron beam that irradiates the sample. In order to improve the electron beam shaping accuracy, the thickness of the aperture is reduced to improve the processing accuracy of the edge of the opening of the aperture.

FIG. 4 is an explanatory diagram of a problem when using the aperture of the first comparative form. Unlike the aperture 10 of the first embodiment, the aperture 90 of the first comparative form does not have the second portion 12 .

FIG. 4 shows a case where the vicinity of the edge of the opening of the aperture 90 is irradiated with an electron beam (arrow in FIG. 4). If the thickness of the aperture 90 is thin, part of the electron beam will pass through the aperture 90 . The transmitted electrons are scattered, and some of the scattered electrons are directed to the deflector 50 located below.

Irradiation of the transmitted electrons onto the deflector 50 causes, for example, impurity burn-in. If impurity burn-in occurs in the deflector 50, for example, electrons charge up the portion where the impurity burn-in occurs. When the electrons charge up in the deflector 50, the electron beam drifts, resulting in deterioration of positional accuracy of writing.

FIG. 5 is an explanatory diagram of the action and effect of the aperture of the first embodiment. The aperture 10 of the first embodiment has a second portion 12 fixed under the first portion 11 . Aperture 10 is partly spaced between first portion 11 and second portion 12 . A gap is provided between the first portion 11 and the second portion 12 .

As shown in FIG. 5, when the aperture 10 is used, most of the electrons traveling outward with respect to the opening collide with the upper surface of the second portion 12 among the electrons transmitted through the first portion 11 . reflected by The energy of the reflected electrons is attenuated by repeated collisions with the first portion 11 and the second portion 12 . As a result, electrons are confined within the gap of aperture 10 .

Therefore, electrons transmitted through the first portion 11 are prevented from being irradiated onto the deflector 50 positioned below. Therefore, for example, the occurrence of burn-in of impurities in the deflector 50 is suppressed. Therefore, for example, the deterioration of the drawing position accuracy is suppressed.

In the aperture 10 , the distance d2 between the first portion 11 and the second portion 12 is larger than the thickness t1 of the end portion E1 of the first opening 21 of the first portion 11 . With this configuration, the gap of the aperture 10 becomes sufficiently large, and some of the electrons that have passed through the first portion 11 can be confined within the gap of the aperture 10 .

FIG. 6 is an explanatory diagram of a problem when using the aperture of the second comparative form. In the aperture 95 of the first comparative example, the distance d2 between the first portion 11 and the second portion 12 is equal to or less than the thickness t1 of the end portion E1 of the first opening 21 of the first portion 11 . That is, the distance d2 between the first portion 11 and the second portion 12 is narrower than the aperture 10 of the first embodiment.

As shown in FIG. 6, since the distance d2 between the first portion 11 and the second portion 12 is narrow, some of the electrons that have passed through the first portion 11 and go outward with respect to the opening are , pass through the aperture 95 without colliding with the second portion 12 . Also, among the electrons that have passed through the first portion 11 , some of the electrons traveling outward with respect to the opening are reflected by the side surfaces of the second portion 12 .

Therefore, of the electrons that have passed through the first portion 11, most of the electrons directed outward with respect to the opening are not confined in the gap between the first portion 11 and the second portion 12. Head down the aperture 95 . Some of the electrons that have traveled downward through the aperture 95 are directed to, for example, the deflector 50 positioned below the aperture 95 .

Therefore, for example, impurity burn-in occurs in the deflector 50 . Therefore, for example, the positional accuracy of drawing is degraded.

Also, the first portion 11 and the second portion 12 are fixed. Therefore, for example, it is not necessary to adjust alignment between the first portion 11 and the second portion 12 for each drawing or each maintenance of the apparatus. Therefore, the throughput of the mask drawing apparatus 100 is improved.

A distance d2 between the first portion 11 and the second portion 12 is preferably 50 μm or more, more preferably 100 μm or more, and even more preferably 200 μm or more. By satisfying the above range, it becomes possible to effectively confine some of the electrons that have passed through the first portion 11 within the gap of the aperture 10 .

If the distance d2 is too large, for example, when the aperture 10 is manufactured, the edge E1 of the first opening 21 of the first portion 11 and the edge E2 of the second opening 22 of the second portion 12 are separated. It becomes difficult to ensure the alignment accuracy of the Therefore, the distance d2 between the first portion 11 and the second portion 12 is preferably 5 mm or less, more preferably 1 mm or less.

The receding amount d1 of the end E2 of the second opening 22 from the end E1 of the first opening 21 is preferably 10 μm or less, more preferably 8 μm or less, and 5 μm or less. is more preferred. By satisfying the above range, among the electrons that have passed through the first portion 11, the amount of electrons that pass through the aperture 10 without colliding with the second portion 12 and heading outward with respect to the opening is reduced. It becomes possible to

The recession amount d1 of the end E2 of the second opening 22 from the end E1 of the first opening 21 is preferably 0.5 μm or more, more preferably 1 μm or more, and more preferably 2 μm or more. It is even more preferable to have By satisfying the above range, when manufacturing the aperture 10, the end E1 of the first opening 21 of the first portion 11 and the end E2 of the second opening 22 of the second portion 12 can be suppressed.

The aspect ratio (d2/d1) between the distance d2 between the first portion 11 and the second portion 12 and the receding amount d1 is preferably 5 or more, preferably 10 or more, and 50 or more. is more preferable. By satisfying the above range, it becomes possible to effectively confine some of the electrons that have passed through the first portion 11 within the gap of the aperture 10 .

FIG. 7 is a table showing the effect of the aperture of the first embodiment. When the electron beam is irradiated near the edge of the opening of the aperture, the amount of electrons that are irradiated to the deflector provided below the aperture among the electrons transmitted through the aperture is shown. The amount of electrons irradiated to the deflector is expressed in arbitrary units as the amount of transmitted electrons. The amount of electrons irradiated to the deflector is obtained by simulation.

Simulation results are shown when the aperture 90 of the first comparative example is used and when the aperture 10 of the first embodiment is used. Regarding the aperture 10 of the first embodiment, the recession amount d1 was fixed at 10 μm, and the distance d2 was set to two conditions of (1) 50 μm and (2) 500 μm.

As is clear from FIG. 7, the amount of electrons irradiated to the deflector is reduced by using the aperture 10 of the first embodiment. In particular, when the distance d2 is 500 μm, that is, the aspect ratio is 50, the amount of transmitted electrons is 16 compared to 100 for the aperture 90 of the first comparative embodiment. That is, the amount of electrons irradiated to the deflector is reduced by 84%.

When the direction in which the end E2 of the second opening 22 retreats with respect to the end E1 of the first opening 21 is defined as the first direction, from the end E2 of the second opening 22 to the first The minimum value of the distance dx in the first direction to the portion 11 of is preferably greater than one-half of the distance d2 between the first portion 11 and the second portion 12, and greater than two-thirds is more preferable.

By satisfying the above range, it becomes possible to effectively confine some of the electrons that have passed through the first portion 11 within the gap of the aperture 10 . That is, it is possible to increase the number of times electrons collide with the first portion 11 or the second portion 12 within the gap, and to effectively attenuate the energy of the electrons.

The minimum value of the distance dx is preferably two times or less the distance d2 between the first portion 11 and the second portion 12 . Moreover, it is preferable that it is 1 mm or less. By satisfying the above range, the strength of the aperture 10 can be guaranteed. Further, by satisfying the above range, processing of the aperture 10 becomes easier.

The thickness t1 of the end E1 of the first opening 21 of the first portion 11 is preferably 1 μm or more. Satisfying the above range ensures the strength of the first portion 11 .

The thickness t1 of the end portion E1 of the first opening 21 of the first portion 11 is preferably 10 μm or less, more preferably 8 μm or less. By satisfying the above range, the processing accuracy of the end portion E1 of the first opening 21 of the aperture 10 is improved, and the electron beam shaping accuracy is improved. Further, by satisfying the above range, the reflection of electrons on the upper surface of the first portion 11 is suppressed, and the irradiation of the reflected electrons to the member existing above the aperture 10 is suppressed.

The thickness t2 of the end E2 of the second opening 22 of the second portion 12 is preferably 10 μm or more, more preferably 20 μm or more. By satisfying the above range, transmission of electrons through the second portion 12 is suppressed.

The thickness t2 of the end E2 of the second opening 22 of the second portion 12 is preferably 100 μm or less, more preferably 60 μm or less. By satisfying the above range, the processing accuracy of the end E2 of the second opening 22 of the aperture 10 is improved. Also, the processing of the aperture 10 becomes easier.

In the charged particle beam writing apparatus of the first embodiment, by thinning the opening edge of the first portion of the aperture, the processing accuracy of the opening edge can be ensured. Therefore, the electron beam shaping accuracy is improved. Further, by confining the electrons transmitted through the first portion in the region where the first portion and the second portion of the aperture are separated, it is possible to reduce the amount of electrons transmitted through the aperture. Therefore, the amount of electrons irradiated to members such as the deflector is suppressed. Therefore, characteristic fluctuations of the charged particle beam writing apparatus are suppressed. For example, it is possible to prevent the electron beam from drifting due to the charge-up of the deflector and the deterioration of the writing position accuracy.

(Second embodiment)
The charged particle beam drawing apparatus and aperture of the second embodiment differ from those of the first embodiment in that the first portion 11 and the second portion 12 of the aperture are made of different materials. Hereinafter, the description of the content that overlaps with the first embodiment will be omitted.

FIG. 8 is a schematic diagram showing the structure of the aperture of the second embodiment. FIG. 8(a) is a top view, and FIG. 8(b) is a cross-sectional view taken along line BB' of FIG. 8(a).

The first portion 11 and the second portion 12 of the aperture 20 are made of different materials. The electron beam transmittance of the second portion 12 is smaller than the electron beam transmittance of the first portion 11 .

The first portion 11 is made of silicon, for example. The second portion 12 is made of a material that is less permeable to electrons than silicon, for example, a material having an atomic weight greater than that of silicon. For example, a high-melting-point metal, which has a high electron shielding ability and is less likely to become a source of contamination in the drawing apparatus, is used as the material. Refractory metals are, for example, molybdenum, tungsten and tantalum.

When the first portion 11 is made of silicon, the thickness t1 of the end portion E1 of the first opening 21 of the first portion 11 is, for example, 1 μm or more and 10 μm or less. When the second portion 12 is made of high melting point metal, the thickness t2 of the end portion E2 of the second opening 22 of the second portion 12 is, for example, 1 μm or more and 10 μm or less.

According to the second embodiment, actions and effects similar to those of the first embodiment are achieved. In addition, by applying a material that is less likely to transmit electrons than the first portion 11 to the second portion 12, the thickness of the second portion 12 can be reduced.

(Third Embodiment)
The charged particle beam drawing apparatus and aperture of the third embodiment differ from those of the first embodiment in that the shape of the opening of the aperture and the application location of the aperture are different. Hereinafter, the description of the content that overlaps with the first embodiment will be omitted.

FIG. 9 is a schematic diagram showing the structure of the aperture of the third embodiment. FIG. 9(a) is a top view, and FIG. 9(b) is a CC' cross-sectional view of FIG. 9(a).

In the third embodiment, for example, the aperture 30 of FIG. 9 is applied to the first aperture 203 of FIGS.

Aperture 30 has a laminated structure of first portion 11 and second portion 12 . The first portion 11 has a first opening 21 and the second portion 12 has a second opening 22 . The shape of the 1st opening part 21 and the 2nd opening part 22 is a rectangle.

According to the third embodiment, actions and effects similar to those of the first embodiment are achieved.

(Fourth embodiment)
The charged particle beam drawing apparatus and aperture of the fourth embodiment differ from those of the first embodiment in that a groove is provided on the upper surface of the second portion of the aperture. Hereinafter, the description of the content that overlaps with the first embodiment will be omitted.

FIG. 10 is a schematic diagram showing the structure of the aperture of the fourth embodiment. FIG. 10(a) is a top view, and FIG. 10(b) is a cross-sectional view along DD' of FIG. 10(a).

Aperture 10 has a plurality of grooves 60 formed in the upper surface of second portion 12 . Aperture 10 has a plurality of grooves 60 formed in a surface facing first portion 11 . A plurality of grooves 60 are formed to surround the second end E2 of the second opening 22 .

FIG. 11 is an enlarged schematic cross-sectional view of the aperture of the fourth embodiment. The width w2 of the groove 60 is, for example, 1 μm or more and 5 μm or less. The interval s between the grooves 60 is, for example, 1 μm or more and 5 μm or less. A depth d4 of the groove 60 is, for example, 2 μm or more and 20 μm or less. The aspect ratio (d4/w) of the groove 60 is, for example, 1 or more and 10 or less.

According to the aperture 40 of the fourth embodiment, by providing the plurality of grooves 60 on the upper surface of the second portion 12, some of the electrons that have passed through the first portion 11 are transferred into the gap of the aperture 40, can be effectively confined. That is, by causing the electrons to collide with the inner surface of the groove 60, the energy of the electrons can be effectively attenuated.

According to the fourth embodiment, actions and effects similar to those of the first embodiment are achieved. By providing a plurality of grooves on the upper surface of the second portion 12, it is possible to further reduce the amount of electrons that pass through the aperture.

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

In the embodiment, the case where the aperture is provided with one opening has been described, but it is also possible to provide a plurality of openings in the aperture.

In the embodiments, the case where the charged particle beam lithography system is a mask lithography system has been described as an example, but the present invention can also be applied to a charged particle beam lithography system that directly draws a pattern on a semiconductor wafer, for example. be.

In addition, descriptions of parts that are not directly necessary for the explanation of the present invention, such as the device configuration and control method, are omitted, but the required device configuration and control method can be appropriately selected and used. For example, the description of the configuration of the control unit that controls the charged particle beam drawing apparatus has been omitted, but it goes without saying that the required configuration of the control unit can be appropriately selected and used. In addition, all charged particle beam drawing apparatuses and apertures that have the elements of the present invention and whose design can be modified as appropriate by those skilled in the art are included in the scope of the present invention.

10 Aperture 11 First portion 12 Second portion 20 Aperture 21 First opening 22 Second opening 30 Aperture 40 Aperture 100 Mask drawing device (charged particle beam drawing device)
101 Sample 105 XY stage (stage)
200 electron beam (charged particle beam)
201 electron gun (irradiation unit)
E1 End of first opening E2 End of second opening

Claims (6)

an irradiation unit that emits a charged particle beam to irradiate a sample;
a stage on which the sample can be placed;
a first portion having a first opening; and a second portion fixed to the stage side of the first portion and having a second opening, wherein the illumination of the second portion is spaced from the first portion, and the inner end portion of the first opening and the second opening portion are separated from each other by the thickness of the inner end portion of the first opening portion of the first portion. an aperture for shaping the charged particle beam emitted from the irradiation unit with a large distance from the part of
with
The diameter of the second opening on the side of the first portion is larger than the diameter of the first opening, and the diameter of the second opening on the side opposite to the side of the first portion is larger than the diameter of the first opening. 2, the diameter of the opening is larger than the diameter of the first opening, and the diameter of the second opening between the side of the first portion and the side opposite to the side of the first portion is larger than the diameter of the first opening. , charged particle beam writer. 2. A charged particle beam drawing apparatus according to claim 1, wherein said interval is 100 [mu]m or more. 3. A charged particle beam drawing apparatus according to claim 1, wherein the charged particle beam transmittance of said second portion is smaller than the charged particle beam transmittance of said first portion. 4. The aspect ratio of the interval and the recession amount of the edge of the second opening from the edge of the first opening is 50 or more. Charged particle beam writer. a first portion having a first opening and a second portion fixed to the first portion and having a second opening;
A portion of the surface of the second portion facing the first portion is separated from the first portion, and the thickness of the inner end portion of the first opening of the first portion is less than the thickness of the first portion. The distance between the inner end of the opening of 1 and the second portion is large,
The diameter of the second opening on the side of the first portion is larger than the diameter of the first opening, and the diameter of the second opening on the side opposite to the side of the first portion is larger than the diameter of the first opening. 2, the diameter of the opening is larger than the diameter of the first opening, and the diameter of the second opening between the side of the first portion and the side opposite to the side of the first portion is larger than the diameter of the first opening. , an aperture that shapes the charged particle beam. 6. The aperture for shaping a charged particle beam according to claim 5, wherein an aspect ratio between said interval and an amount of recession of said edge of said second opening from said edge of said first opening is 50 or more.

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