JP2017173810A - Mask for charge particle beam exposure and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mask for charge particle beam exposure capable of being stably used and a manufacturing method capable of stably manufacturing the mask for charge particle beam exposure.SOLUTION: A mask for charge particle beam exposure has a thin sheet part having a plurality of apertures in a pattern area and thickness in a range of 0.1 μm to 30 μm, a support part with a frame shape, on one surface of the thin sheet part, which supports an outside of the pattern area and a reinforcement part, in the pattern area of the one surface of the thin sheet part, which is positioned while surrounding the apertures in an area apart from a circumference of the apertures and continues with the support part.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a charged particle beam exposure mask, and more particularly to a charged particle beam exposure mask in which a desired opening is provided in a thin plate portion that does not transmit a charged particle beam and a method for manufacturing the same.

With the miniaturization and high integration of integrated circuits such as semiconductor devices, a charged particle beam lithography method using a charged particle beam such as an electron beam or an ion beam is used for pattern formation instead of the photolithography method. In the charged particle beam lithography method, a charged particle beam is directly drawn on an exposure object using a charged particle beam exposure apparatus, and a stencil type charged particle beam exposure is performed between the charged particle beam exposure apparatus and the exposure object. There is a method of pattern exposure with a mask for use.
As a stencil type charged particle beam exposure mask, a mask provided with a desired opening in a thin plate portion that does not transmit a charged particle beam is used. As such a mask, for example, a stencil type mask (Patent Document 1) in which the thickness of the thin plate portion having a thickness of about 1 μm and an elongated shape in plan view is set to about 10 mm, a few nm is used for the thin plate portion. A stencil-type mask (Patent Document 2) or the like in which openings having a size of ˜several μm are provided in a desired arrangement is disclosed.

JP 2009-274347 A JP 2013-12682 A

However, the thin plate portion constituting the conventional stencil-type charged particle beam exposure mask has a low mechanical strength. Therefore, there arises a problem that the thin plate portion is deformed due to the influence of the stress in the manufacturing process, the distortion of the substrate, or the influence of the water pressure at the time of cleaning. Such a problem becomes more prominent as the area of the planar view shape of the thin plate portion increases. For example, even the conventional stencil-type masks described in Patent Document 1 and Patent Document 2 described above are prone to deformation and breakage of the thin plate portion in the manufacturing process, and it has been difficult to manufacture stably. In use, there is a problem that the thin plate portion is easily deformed or damaged by the action of stress.
The present invention has been made in view of the above-described actual situation, and a charged particle beam exposure mask that can be stably used, and a manufacturing method that can stably manufacture such a charged particle beam exposure mask. One purpose is to provide

  In order to achieve such an object, a charged particle beam exposure mask as an embodiment of the present invention has a thin plate having a plurality of openings in a pattern region and having a thickness in a range of 0.1 μm to 30 μm. A frame-shaped support portion that supports the outside of the pattern region on one surface of the thin plate portion, and from the periphery of the opening portion in the pattern region on the one surface of the thin plate portion. A configuration is provided that includes a reinforcing portion that is positioned so as to surround the opening portion and is continuous with the support portion in a separated region.

As another aspect of the present invention, the reinforcing portion is configured to be positioned so as to surround the opening in a region separated from the periphery of all the openings.
As another aspect of the present invention, the distance between the reinforcing portion and the periphery of the opening is 1 μm or more.

As another aspect of the present invention, the corner portion present in the contour shape in plan view of the portion surrounding the opening in the reinforcing portion is round.
As another aspect of the present invention, the radius of curvature of the round shape is in the range of 1 μm to 100 μm.

As another aspect of the present invention, the radius of curvature of the round shape is configured to be equal to the distance at which the reinforcing portion is separated from the periphery of the opening.
As another aspect of the present invention, the thin plate portion, the support portion, and the reinforcing portion are made of a material having etching selectivity.

As another aspect of the present invention, the thin plate portion is a layer made of silicon, and the reinforcing portion is a composite of a layer made of silicon oxide and a layer made of silicon, and the oxidation portion is formed from the thin plate portion side. It was set as the structure located in order of the layer which consists of silicon, and the layer which consists of said silicon | silicone.
As another aspect of the present invention, the thin plate portion is configured to be a layer made of silicon nitride, silicon carbide, gallium arsenide, diamond-like carbon, sapphire, or metal.

  A method for manufacturing a charged particle beam exposure mask according to an embodiment of the present invention includes a step of defining a pattern region on one principal surface of a substrate, forming a hole in the substrate in the pattern region, and the hole A step of forming a resin layer on the substrate so as to cover, and etching the substrate in a desired pattern from the main surface side facing the one main surface of the substrate until the hole is exposed; A frame-shaped support portion located outside the pattern region; and the support portion that is located within the pattern region so as to surround the opening portion in a region separated from the periphery of the opening portion of the exposed hole portion, and the support portion Forming a reinforcing portion continuous with the portion, and setting the exposed depth of the hole to a desired depth within a range of 0.1 μm to 30 μm, and removing the resin layer. It was set as the structure which has.

As another aspect of the present invention, the resin layer has a thickness in the range of 5 μm to 30 μm.
As another aspect of the present invention, the substrate is configured to be an SOI substrate in which a silicon layer is stacked with a silicon oxide layer interposed therebetween.

As another aspect of the present invention, the substrate is a single substrate selected from the group consisting of silicon, silicon compounds, compound semiconductors, carbon, sapphire, and metal, or a stacked substrate formed by stacking two or more. The configuration is as follows.
As another aspect of the present invention, the laminated substrate is configured to be a substrate formed by laminating two or more materials having etching selectivity.

The charged particle beam exposure mask of the present invention hardly deforms or breaks the thin plate portion and can be used stably.
The manufacturing method of the charged particle beam exposure mask according to the present invention prevents the deformation and breakage of the thin plate portion in the manufacturing process, and enables stable manufacturing.

FIG. 1 is a plan view showing an embodiment of a charged particle beam exposure mask of the present invention. FIG. 2 is a partially enlarged cross-sectional view taken along line II of the charged particle beam exposure mask shown in FIG. FIG. 3 is a plan view showing another embodiment of the charged particle beam exposure mask of the present invention. 4 is a cross-sectional view taken along line II-II of the charged particle beam exposure mask shown in FIG. FIG. 5 is a plan view showing another embodiment of the charged particle beam exposure mask of the present invention. 6 is a cross-sectional view of the charged particle beam exposure mask shown in FIG. 5 taken along line III-III. FIG. 7 is a plan view showing another embodiment of the charged particle beam exposure mask of the present invention. FIG. 8 is a cross-sectional view taken along line IV-IV of the charged particle beam exposure mask shown in FIG. FIG. 9 is a cross-sectional view taken along line VV of the charged particle beam exposure mask shown in FIG. FIG. 10 is a plan view showing another embodiment of the charged particle beam exposure mask of the present invention. 11 is a cross-sectional view taken along the line VI-VI of the charged particle beam exposure mask shown in FIG. FIG. 12 is a view for explaining another embodiment of the charged particle beam exposure mask of the present invention. FIG. 13 is a view for explaining another embodiment of the charged particle beam exposure mask of the present invention. FIG. 14 is a view for explaining another embodiment of the charged particle beam exposure mask of the present invention. FIG. 15 is a plan view showing another embodiment of the charged particle beam exposure mask of the present invention. 16 is a cross-sectional view taken along line VII-VII of the charged particle beam exposure mask shown in FIG. FIG. 17 is a plan view showing another embodiment of the charged particle beam exposure mask of the present invention. 18 is a cross-sectional view taken along line VIII-VIII of the charged particle beam exposure mask shown in FIG. FIG. 19 is a process diagram for explaining one embodiment of a method for producing a charged particle beam exposure mask of the present invention. FIG. 20 is a process diagram for describing one embodiment of a method for producing a charged particle beam exposure mask of the present invention. FIG. 21 is a process diagram for explaining another embodiment of the method for producing a charged particle beam exposure mask of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Note that the drawings are schematic or conceptual, and the dimensions of each member, the ratio of sizes between the members, etc. are not necessarily the same as the actual ones, and represent the same members. However, in some cases, the dimensions and ratios may be different depending on the drawing.
In the present specification and the like, a numerical range expressed using “to” means a range including each of the numerical values described before and after “to” as a lower limit value and an upper limit value.
In this specification and the like, terms such as “film”, “sheet”, and “plate” are not distinguished from each other on the basis of the difference in names. For example, the “plate” is a concept including members that can be generally called “sheet” and “film”.

[Charged particle beam exposure mask]
The charged particle beam exposure mask of the present invention will be described.
FIG. 1 is a plan view showing an embodiment of a charged particle beam exposure mask of the present invention, and FIG. 2 is a partially enlarged sectional view taken along line II of the charged particle beam exposure mask shown in FIG. is there. 1 and 2, a charged particle beam exposure mask 11 includes a thin plate portion 12 having a plurality of openings 14 in a pattern region 13, and one surface 12 a of the thin plate portion 12 on the outside of the pattern region 13. A frame-shaped support portion 15 to be supported, and a reinforcement positioned so as to surround the opening portion 14 in a pattern region 13 on one surface 12a of the thin plate portion 12 and spaced from the peripheral edge 14p of each opening portion 14. A portion 17 is provided. The thin plate portion 12 constituting the charged particle beam exposure mask 11 has a thickness in the range of 0.1 μm to 30 μm, and the reinforcing portion 17 is continuous with the support portion 15. In FIG. 1, the periphery of the pattern region 13 is indicated by a one-dot chain line. In FIG. 1, the opening 14 is omitted.

  In the illustrated charged particle beam exposure mask 11, a silicon oxide layer (an embedded silicon oxide layer; also referred to as a box layer) is disposed on a single crystal silicon substrate, and a thin plate portion of the single crystal silicon layer is formed on the silicon oxide layer. This is an example in which a pattern region 13 is defined in a single crystal silicon layer of a thin plate portion of an SOI substrate, which is manufactured using a placed SOI (Silicon on Insulator) substrate. Therefore, the material of the thin plate portion 12 of the charged particle beam exposure mask 11 is single crystal silicon. When an SOI substrate is not used for the charged particle beam exposure mask 11, a silicon substrate, a silicon compound substrate such as silicon nitride, silicon carbide, or silicon oxide, a compound semiconductor substrate such as gallium arsenide, a diamond-like substrate is used. Carbon substrates such as carbon, sapphire substrates, metal substrates such as stainless steel, aluminum, and chromium can be used, and a laminate composed of a composite material selected from desired materials including these substrate materials is used as a substrate. Can be used. Therefore, the material and thickness of the thin plate portion 12 correspond to the substrate to be used. For example, when the material of the thin plate portion 12 is single crystal silicon, the thickness of the thin plate portion 12 is, for example, 1 μm to 30 μm, and when the material of the thin plate portion 12 is silicon nitride, for example, 0.1 μm to In the case of silicon carbide, for example, 0.1 μm to 3 μm, and in the case of diamond-like carbon, for example, 0.1 μm to 2 μm.

In the illustrated example, the outer shape of the charged particle beam exposure mask 11 is a rectangle, and the pattern region 13 defined in the thin plate portion 12 is also a rectangle. However, the shape is not limited to a rectangle. The opening shape, arrangement position, and size of the opening 14 provided in the pattern region 13 of the thin plate portion 12 can be appropriately set according to the purpose of use of the charged particle beam exposure mask 11.
The support portion 15 of the charged particle beam exposure mask 11 has a frame shape that surrounds the outside of the pattern region 13 and can support the surface 12 a of the thin plate portion 12. In the charged particle beam exposure mask 11 using an SOI substrate, the support portion 15 is formed of a stack of a single crystal silicon substrate 15a and a silicon oxide layer 15b constituting the SOI substrate. In this support portion 15, the silicon oxide layer 15 b is fixed to one surface 12 a of the thin plate portion 12 and outside the pattern region 13, thereby supporting the thin plate portion 12.

  When an SOI substrate is not used for the charged particle beam exposure mask 11, as described above, the substrate is a silicon substrate, a silicon compound substrate such as silicon nitride, silicon carbide, or silicon oxide, or a compound semiconductor substrate such as gallium arsenide. Carbon substrates such as diamond-like carbon (DLC), sapphire substrates, and metal substrates such as stainless steel, aluminum, and chromium can be used. Moreover, the laminated body which consists of a composite material selected from the desired materials containing these board | substrate materials can be used as a board | substrate. In the laminate, the layer constituting the thin plate portion 12 and the layer constituting the support portion 15 and the reinforcing portion 17 can be selectively etched, and the thin plate portion 12 is a self-supporting thin film (membrane). Even if there is no member corresponding to the above 15b, it is sufficient that the thin plate portion 12 can maintain the state having the opening portion 14, for example, the laminate can have a two-layer structure. .

  Moreover, in order to give etching selectivity between the layer which comprises the thin-plate part 12, and the layer which comprises the support part 15 and the reinforcement part 17, it is good also considering a laminated body as a structure of three or more layers. When the laminated body has a three-layer structure, etching selectivity exists between the substrate corresponding to the member 12 and the substrate corresponding to the member 15b, and also corresponds to the substrate and member 15b corresponding to the member 15a. The combination can be set so that there is an etching selectivity with the substrate to be processed. For example, combinations of materials as shown in Table 1 below can be given. In the present invention, the phrase “etching selectivity between different layers and materials” means that the etching rate may be different when etching is performed under the same conditions.

Therefore, the material of the support portion 15 corresponds to the substrate to be used. The thickness of the support portion 15 (thickness in the direction of arrow a shown in FIG. 2) can be set in consideration of the material of the support portion 15, the size of the frame shape in plan view, and the like. It can be appropriately set in the range of 800 μm, preferably 200 μm to 400 μm.
The reinforcing portion 17 constituting the charged particle beam exposure mask 11 is provided in the pattern region 13 on the one surface 12a of the thin plate portion 12 and in the region separated from the peripheral edge 14p of each opening portion 14. It is located so as to surround it. The distance L at which the reinforcing portion 17 is separated from the peripheral edge 14p of the opening 14 is preferably 1 μm or more, more preferably 1.2 μm or more, and particularly preferably 5 μm or more. In consideration of the alignment between the hole 64 and the opening 85a of the resist pattern 85 in the production of the mask for line exposure, 10 μm or more is more preferable. Moreover, the upper limit of the distance L can be set according to the magnitude | size of the thin plate part 12 which exists between the adjacent opening parts 14, for example, can be 100 micrometers or less, Preferably it is 50 micrometers or less. If the distance L at which the reinforcing portion 17 is separated from the peripheral edge 14p of the opening 14 is less than 1 μm, the efficiency with which the charged particle beam passes through the opening 14 may be reduced. If the distance L exceeds 100 μm, effective reinforcement of the thin plate portion 12 by the reinforcing portion 17 cannot be obtained, and stress acting on the charged particle beam exposure mask 11 acts on the thin plate portion 12 around the opening 14. It may not be possible to prevent this. Note that the distance L at which the reinforcing portion 17 is separated from the peripheral edge 14p of the opening 14 may be the same in all the openings 14 and in the entire area around the single opening 14. Further, the distance L may be different depending on the position of the opening 14 in the pattern region 13, and the distance L may be different around one opening 14.

In the charged particle beam exposure mask 11 using the SOI substrate, the reinforcing portion 17 is formed of a stack of single crystal silicon 17a and silicon oxide 17b constituting the SOI substrate, like the support portion 15. The thickness of the reinforcing portion 17 (the thickness in the direction of arrow a shown in FIG. 2) may be equal to the thickness of the support portion 15. Further, the reinforcing portion 17 may be thinner than the support portion 15, and the thickness of the reinforcing portion 17 may be different depending on the position in the pattern region 13.
Such a reinforcing portion 17 is located so as to surround the opening portion 14 and is continuous with the supporting portion 15 located outside the pattern region 13. For this reason, even if stress or the like is applied to the charged particle beam exposure mask 11, distortion of the charged particle beam exposure mask 11 is suppressed, and deformation of the thin plate portion 12, damage to the opening portion 14, and the like are prevented. be able to. In addition, the reinforcing portion 17 also exhibits a heat radiating action for releasing the heat generated by the collision of the charged particle beam with the thin plate portion 12 to the outside.

Next, the charged particle beam exposure mask of the present invention will be described with specific opening shapes.
FIG. 3 is a plan view showing another embodiment of the charged particle beam exposure mask of the present invention, and FIG. 4 is a cross-sectional view taken along the line II-II of the charged particle beam exposure mask shown in FIG. . 3 and 4, the charged particle beam exposure mask 21 includes a thin plate portion 22 having a plurality of rectangular openings 24 in a rectangular pattern region 23 (shown by a one-dot chain line in FIG. 3), and the thin plate portion 22. A frame-shaped support portion 25 that supports the outer side of the pattern region 23 on one surface 22a, and a region that is within the pattern region 23 on one surface 22a of the thin plate portion 22 and that is separated from the peripheral edge 24p of each opening 24 In addition, a reinforcing portion 27 is provided so as to surround the opening 24. The thin plate portion 22 constituting the charged particle beam exposure mask 21 has a thickness in the range of 0.1 μm to 30 μm, and the reinforcing portion 27 is continuous with the support portion 25. The ratio of the outer dimension of the charged particle beam exposure mask 21 to the dimension of the opening 24, the number of openings 24, etc. are described for convenience. Moreover, in FIG. 3, the outline of the reinforcement part 27 located apart from the peripheral edge 24p of each opening part 24 is shown with the chain line.

Similarly to the charged particle beam exposure mask 11, the charged particle beam exposure mask 21 is an example using an SOI substrate. Accordingly, the thin plate portion 22, the support portion 25, and the reinforcement portion 27 that constitute the charged particle beam exposure mask 21 are the same as the thin plate portion 12, the support portion 15, and the reinforcement portion 17 that constitute the charged particle beam exposure mask 11. be able to.
The rectangular openings 24 located in the pattern region 23 of the thin plate portion 22 are arranged so as to form a grid pattern in 4 columns × 3 rows. The contour of the reinforcing portion 27 (shown by a chain line in FIG. 3) is located at a position separated from the peripheral edge 24p of the opening 24 by a distance L. The distance L at which the reinforcing portion 27 is separated from the peripheral edge 24p of the opening 24 is preferably 1 μm or more, more preferably 1.2 μm or more, and particularly preferably 5 μm or more, as described above. The upper limit of the distance L is, for example, 100 μm, preferably 50 μm. Further, the distance L may be the same in all the openings 24 and in the entire area around one opening 24. Further, the distance L may be different depending on the position of the opening 24 in the pattern region 23, and the distance L may be different around one opening 24.

Such a reinforcing portion 27 has a lattice shape surrounding the opening 24, and is continuous with the support portion 25 at the periphery of the pattern region 23. Therefore, even if stress or the like is applied to the charged particle beam exposure mask 21, distortion of the charged particle beam exposure mask 21 is suppressed, and deformation of the thin plate portion 22, damage to the opening 24, and the like are prevented. Can do. In addition, the reinforcing portion 27 also exhibits a heat dissipation action that releases heat generated by collision of the charged particle beam with the thin plate portion 22 to the outside.
Note that the arrangement of the openings 24 is not limited to the grid. FIG. 5 is a plan view showing another embodiment of the charged particle beam exposure mask of the present invention, and FIG. 6 is a sectional view taken along line III-III of the charged particle beam exposure mask shown in FIG. . 5 and 6, in the charged particle beam exposure mask 21 ', in the opening 24 located in the pattern region 23, an array group including three openings 24 in the Y-axis direction has four rows in the X-axis direction. It is the same as the above-described charged particle beam exposure mask 21 except that the adjacent array groups are shifted by a distance y in the Y-axis direction. Therefore, the same member number is attached to the same member. Also in such a charged particle beam exposure mask 21 ′, distortion of the charged particle beam exposure mask 21 ′ is suppressed, and deformation of the thin plate portion 22, damage to the opening portion 24, and the like are prevented.

  FIG. 7 is a plan view showing another embodiment of the charged particle beam exposure mask of the present invention, and FIG. 8 is a sectional view taken along line IV-IV of the charged particle beam exposure mask shown in FIG. 9 is a cross-sectional view taken along line VV of the charged particle beam exposure mask shown in FIG. 7 to 9, a charged particle beam exposure mask 31 includes a thin plate portion 32 having a plurality of T-shaped openings 34 in a rectangular pattern region 33 (shown by a one-dot chain line in FIG. 7), and the thin plate portion 32. A frame-shaped support portion 35 that supports the outer side of the pattern region 33 on one surface 32a of the thin plate portion 32 and is spaced from the peripheral edge 34p of each opening portion 34 in the pattern region 33 on the one surface 32a of the thin plate portion 32. In the region, a reinforcing portion 37 is provided so as to surround the opening 34. The thin plate portion 32 constituting the charged particle beam exposure mask 31 has a thickness in the range of 0.1 μm to 30 μm, and the reinforcing portion 37 is continuous with the support portion 35. The ratio of the outer dimension of the charged particle beam exposure mask 31 to the dimension of the opening 34, the number of the openings 34, etc. are described for convenience. Moreover, in FIG. 7, the outline of the reinforcement part 37 located apart from the peripheral edge 34p of each opening part 34 is shown with the chain line.

  Similarly to the charged particle beam exposure mask 11, the charged particle beam exposure mask 31 is an example using an SOI substrate. Accordingly, the thin plate portion 32, the support portion 35, and the reinforcing portion 37 constituting the charged particle beam exposure mask 31 are the same as the thin plate portion 12, the supporting portion 15, and the reinforcing portion 17 constituting the charged particle beam exposure mask 11. be able to.

In the illustrated example, twelve T-shaped openings 34 are arranged in the pattern region 33 of the thin plate portion 32, and the contour of the reinforcing portion 37 (see FIG. 7) is located at a distance L from the peripheral edge 34 p of the opening 34. Is indicated by a chain line). The distance L at which the reinforcing portion 37 is separated from the peripheral edge 34p of the opening 34 is preferably 1 μm or more, more preferably 1.2 μm or more, and particularly preferably 5 μm or more, as described above. The upper limit of the distance L is, for example, 100 μm, preferably 50 μm. Further, the distance L may be the same in all the openings 34 and in the entire area around one opening 34. Further, the distance L may be different depending on the position of the opening 34 in the pattern region 33, and the distance L may be different around one opening 34.
Such a reinforcing portion 37 is continuous with the support portion 35 at the peripheral edge of the pattern region 33. Therefore, even if stress or the like is applied to the charged particle beam exposure mask 31, the charged particle beam exposure mask 31 is prevented from being distorted, and deformation of the thin plate portion 32, damage to the opening portion 34, and the like are prevented. Can do. In addition, the reinforcing portion 37 also exhibits a heat dissipation action that releases heat generated by collision of the charged particle beam with the thin plate portion 32 to the outside.

  In the above-described embodiment of the charged particle beam exposure mask, the shape of the openings 24 and 34 that the thin plate portions 22 and 32 have in the pattern regions 23 and 33 is one, but the charged particle beam exposure mask of the present invention. May have openings of different shapes. FIG. 10 is a plan view showing an embodiment of such a charged particle beam exposure mask of the present invention, and FIG. 11 is a cross-sectional view taken along the line VI-VI of the charged particle beam exposure mask shown in FIG. It is. 10 and 11, a charged particle beam exposure mask 41 is a thin plate portion having three types of openings 44 in a rectangular pattern region 43 (shown by a one-dot chain line in FIG. 10) of a circular shape, a rectangular shape, and a triangular shape. 42, a frame-shaped support portion 45 that supports the outer side of the pattern region 43 on one surface 42a of the thin plate portion 42, and each opening portion in the pattern region 43 of the one surface 42a of the thin plate portion 42. The reinforcement part 47 located so that the said opening part 44 may be enclosed in the area | region spaced apart from the peripheral edge 44p of 44 is provided. In the pattern region 43, there are five adjacent rows of arrays of three openings 44 having a circular shape, a rectangular shape, and a triangular shape in the Y-axis direction, adjacent to each other in five rows in the X-axis direction. Each adjacent array group is positioned in a state where the distance y is shifted in the Y-axis direction. The thin plate portion 42 having such an opening 44 has a thickness in the range of 0.1 μm to 30 μm, and the reinforcing portion 47 is continuous with the support portion 45. The ratio of the outer dimension of the charged particle beam exposure mask 41 to the dimension of the opening 44, the number of the openings 44, etc. are described for convenience. Further, in FIG. 10, the outline of the reinforcing portion 47 positioned away from the peripheral edge 44 p of each opening 44 is indicated by a chain line.

Similarly to the charged particle beam exposure mask 11, the charged particle beam exposure mask 41 is an example using an SOI substrate. Accordingly, the thin plate portion 42, the support portion 45, and the reinforcing portion 47 that constitute the charged particle beam exposure mask 41 are the same as the thin plate portion 12, the support portion 15, and the reinforcing portion 17 that constitute the charged particle beam exposure mask 11. be able to.
Further, in the charged particle beam exposure mask, the reinforcing portion may have a round shape at a corner portion present in a contour shape in plan view of a portion surrounding the opening. FIG. 12 is a diagram for explaining such a round shape by taking the opening 24 and the reinforcing portion 27 of the above-described charged particle beam exposure mask 21 as an example. FIG. 12A shows a reinforcing portion 27 that is positioned so as to surround the opening 24 in a region separated from the peripheral edge 24p of the rectangular opening 24 by a distance L with hatching. In FIG. 12A, there are four corner portions 27c in the contour shape (shown by a chain line) in a plan view of a portion surrounding the opening 24 of the reinforcing portion 27. On the other hand, in FIG. 12B, the reinforcing portion 27 has four round corners 27r in the contour shape (shown by chain lines) in a plan view of the portion surrounding the opening 24.

  FIG. 13 is a view for explaining the above round shape by taking the opening 34 and the reinforcing portion 37 of the above-mentioned charged particle beam exposure mask 31 as an example. FIG. 13A shows a reinforcing portion 37 that is positioned so as to surround the opening 34 in a region spaced apart from the peripheral edge 34p of the T-shaped opening 34 by a diagonal line. In FIG. 13A, there are eight corners 37c in the contour shape (shown by a chain line) in plan view of the portion surrounding the opening 34 of the reinforcing portion 37. On the other hand, in FIG. 13B, the reinforcing portion 37 has eight round corners 37r in the contour shape (shown by a chain line) of the portion surrounding the opening 34 in plan view.

The curvature radii of the round shapes 27r and 37r can be appropriately set within a range of 1 μm to 100 μm, preferably 1 μm to 50 μm, for example. Such a radius of curvature can be set according to the internal angle of the corners of the opening shapes of the openings 24 and 34. For example, when the internal angle is small, the radius of curvature is small and when the internal angle is large. Can set a large radius of curvature. Further, the radius of curvature may be equal to the distance L from the peripheral edges 24p, 34p of the openings 24, 34 to the reinforcing portions 27, 37. In this case, being equal to the distance L means a range of 0.9L to 1.1L.
In this way, in the reinforcing portion, the corner portion of the contour shape in plan view of the portion surrounding the opening is rounded, so that a large stress or the like acts on the charged particle beam exposure mask 21 and the charged particle beam exposure Even if the mask 21 is slightly distorted, the distortion stress is relieved in the portions having the round shapes 27r and 37r, and the deformation of the thin plate portions 22 and 32, the breakage of the openings 24 and 34, and the like can be prevented.

  Further, in the charged particle beam exposure mask, when the interval between adjacent openings is large, the contour shape in plan view of the reinforcing portion surrounding the openings can be a curved shape such as a circle or an ellipse. FIG. 14 is a diagram for explaining such a curved shape by taking the opening 34 and the reinforcing portion 37 (shown with diagonal lines) of the above-mentioned charged particle beam exposure mask 31 as an example. In FIG. 14, the contour shape (shown by a chain line) of the reinforcing portion 37 surrounding the opening 34 in a plan view is a circle surrounding the T-shaped opening 34. In this case, the minimum separation distance Lmin and the maximum separation distance Lmax between the circular contour shape and the T-shaped opening 34 are preferably within the above-mentioned distance L range, but are not limited thereto.

  Further, the charged particle beam exposure mask may include an opening that is not surrounded by a reinforcing portion. FIG. 15 is a plan view for explaining such an embodiment using the above-described charged particle beam exposure mask 21 as an example, and FIG. 16 is a diagram VII-VII of the charged particle beam exposure mask shown in FIG. It is sectional drawing in a line. 15 and 16, in the charged particle beam exposure mask 21 ″, in the opening 24 located in the pattern region 23, the two central openings 24 are not surrounded by the reinforcing portion 27. The two members 24 are the same as the above-described charged particle beam exposure mask 21 except that the reinforcing portion 27 does not exist between the two openings 24. Therefore, the same members are denoted by the same member numbers. As described above, the position, number, and existence density of the openings 24 that are not surrounded by the reinforcing portion 27 can be set as appropriate within a range in which distortion is suppressed in the charged particle beam exposure mask 21 ″. it can.

  Furthermore, the charged particle beam exposure mask may include a reinforcing portion that is continuous with the support portion but is not continuous with the thin plate portion. FIG. 17 is a plan view for explaining the charged particle beam exposure mask of such an embodiment, and FIG. 18 is a cross-sectional view taken along line VIII-VIII of the charged particle beam exposure mask shown in FIG. . 17 and 18, the charged particle beam exposure mask 51 supports a thin plate portion 52 having a plurality of openings 54 in the pattern region 53 and the outside of the pattern region 53 on one surface 52a of the thin plate portion 52. A frame-shaped support portion 55 and a reinforcing portion 57 that is spaced from the peripheral edge 54p of each opening 54 and is located so as to surround the opening 54 in the pattern region 53 of the thin plate portion 52 in plan view. The thin plate portion 52 constituting the charged particle beam exposure mask 51 has a thickness in the range of 0.1 μm to 30 μm. The reinforcing portion 57 has a tapered side surface 57 a and continues to the support portion 55, but does not continue to the thin plate portion 52. The distance between the end portion of the reinforcing portion 57 located on the thin plate portion 52 side and the one surface 52a of the thin plate portion 52 is reinforced by the reinforcing portion 57 to such an extent that deformation of the thin plate portion 52 does not occur. As long as it is, there is no particular limitation.

  In the charged particle beam exposure mask 51 shown in FIGS. 17 and 18, all the reinforcing portions 57 located in the pattern region 53 are not continuous to the thin plate portion 52, but the embodiment is limited to such a mode. Instead, at least a part of the reinforcing portion 57 located in the pattern region 53 may not be continuous with the thin plate portion 52. For example, among the openings 54 of 4 rows × 5 columns located in the pattern region 53, the reinforcing portion 57 surrounding the opening 54 of 2 rows × 3 columns located in the center of the pattern region 53 is continuous with the thin plate portion 52. Alternatively, the reinforcing portion 57 surrounding the opening 54 located around the opening 54 may be continuous with the thin plate portion 52, or vice versa, that is, the reinforcing portion 57 surrounding the opening 54 located in the center. However, the reinforcing portion 57 surrounding the opening 54 located around the thin plate portion 52 may not be continuous with the thin plate portion 52.

  The above-described embodiments of the charged particle beam exposure mask are examples, and the present invention is not limited to such embodiments. For example, the shape, arrangement, and the like of the opening are not limited to the above-described embodiments, and can be appropriately set according to the purpose of use of the charged particle beam exposure mask.

  The charged particle beam exposure mask of the present invention can be used for pattern exposure as a stencil-type charged particle beam exposure mask interposed between a charged particle beam exposure apparatus and an exposure object. Used as an aperture to be installed in the lens barrel of a charged particle beam exposure device by making the outer dimensions and shape of the mask for line exposure, and the size, shape, size and shape of the opening of the pattern area appropriate. It is also possible to do. Therefore, the charged particle beam exposure mask of the present invention includes an aperture constituting the charged particle beam exposure apparatus together with the stencil type charged particle beam exposure mask between the charged particle beam exposure apparatus and the exposure object. It is.

[Method for producing mask for charged particle beam exposure]
Next, the manufacturing method of the mask for charged particle beam exposure of this invention is demonstrated.
FIG. 19 and FIG. 20 are process diagrams for explaining an embodiment of the method for manufacturing a charged particle beam exposure mask of the present invention. The charged particle beam exposure mask 21 is taken as an example.
In the present embodiment, as a substrate 61 for forming a charged particle beam exposure mask, a support substrate 65a, a box layer 65b containing silicon oxide laminated on the support substrate 65a, and the box layer 65b are arranged. An SOI substrate having a single crystal silicon layer 62 having a thickness in the range of 1 μm to 30 μm is prepared. Then, a pattern region 63 is defined in the single crystal silicon layer 62 of the substrate 61, and a hard mask material layer 71 is formed on the main surface 61a of the substrate 61 and the main surface 61b opposed thereto. That is, the hard mask material layer 71a is formed over the single crystal silicon layer 62 included in the substrate 61, and the hard mask material layer 71b is formed over the support substrate 65a (FIG. 19A).

Although the thickness of the substrate 61 is not particularly limited, for example, a substrate having a thickness in the range of 100 μm to 800 μm can be used, and considering the workability of the substrate, the thickness of the substrate 61 is preferably in the range of 200 μm to 400 μm. .
As the hard mask material layers 71a and 71b, for example, metal materials such as silicon oxide, chromium, and aluminum can be used, and those that can be etched with the same etchant as the box layer 65b are preferable. Hereinafter, a process using the same silicon oxide as the box layer 65b as the hard mask material layers 71a and 71b will be described.
Next, a resist pattern 75 is formed on the hard mask material layer 71a (FIG. 19B). The resist pattern 75 has a desired opening 75 a in the pattern region 63.

  Next, the hard mask material layer 71a is etched using the resist pattern 75 as a mask to form a hard mask 71'a, and the single crystal silicon layer 62 is etched using the hard mask 71'a as a mask (FIG. 19C). . In this etching, the box layer 65 b acts as an etching stopper, and an opening is formed in the single crystal silicon layer 62. As a result, a hole 64 is formed in the substrate 61, and the depth of the hole 64 corresponds to the thickness of the single crystal silicon layer 62 and falls within the range of 1 μm to 30 μm. Therefore, in the post-process, the support substrate 65a is etched, the exposed box layer 65b is removed, and the depth of the hole 64 is 1 μm to 30 μm when the hole 64 is exposed to the support substrate 65a side. The desired depth is within the range.

Etching of the hard mask material layer 71a can be performed by wet etching or dry etching. When the hard mask material layer 71a made of silicon oxide is etched by wet etching, hydrofluoric acid or a chemical solution containing hydrofluoric acid can be used as an etchant. On the other hand, when the hard mask material layer 71a made of silicon oxide is etched by dry etching, dry etching using trifluoromethane (CHF ₃ ) gas or hexafluoroethane (C ₂ F ₆ ) gas can be performed. Since dry etching has anisotropy, a pattern having a size almost as designed can be formed.
The single crystal silicon layer 62 can be etched by wet etching or dry etching. When the single crystal silicon layer 62 is etched by wet etching, an aqueous KOH solution, ethylenediamine / pyrocatechol (EDP), or 4-methylammonium hydroxide (TMAH) can be used. On the other hand, when the single crystal silicon layer 62 is etched by dry etching, dry etching using carbon tetrafluoride (CF ₄ ), sulfur hexafluoride (SF ₆ ), or hydrogen bromide (HBr) can be performed.

Next, a resin layer 81 is formed so as to cover the hole 64, and a resist pattern 85 is formed on the hard mask material layer 71b (FIG. 20A).
The resin layer 81 is formed for the purpose of protecting the hole 64 and for the purpose of suppressing distortion when the support substrate 65a is etched in a subsequent process. Therefore, the resin layer 81 is preferably formed with a thickness sufficient to obtain a certain rigidity, and specifically, the thickness of the resin layer 81 can be appropriately set within a range of 5 μm to 30 μm. In the illustrated example, such a resin layer 81 is formed over the entire area of the substrate, but may be formed at least in the pattern region 63. In the formation of the resin layer 81, a known resin used as a resist or the like can be used. The resin layer 81 is formed by applying a solution of a resin material dissolved in a solvent by a spin coating method or the like and performing a heat treatment. be able to. The thickness of the resin layer 81 can be controlled by adjusting the viscosity of the solution by adjusting the concentration of the resin material and additives, and further adjusting the rotation speed of the substrate during application of the solution. When a desired thickness cannot be obtained by a single application, the application and curing may be repeated a plurality of times until the resin layer has a desired thickness.
The resist pattern 85 has an opening 85 a at a position facing the hole 64. The opening 85a has an opening size and an opening shape suitable for forming a reinforcing portion 67 'to be described later in consideration of an etching method, etching conditions, a material of the substrate 61, and the like.

  Next, the hard mask material layer 71b is etched using the resist pattern 85 as a mask to form a hard mask 71'b, and the support substrate 65a is etched using the hard mask 71'b as a mask (FIG. 20B). Even in this etching, the box layer 65b acts as an etching stopper. As a result, the frame-shaped support portion 65 ′ located outside the pattern region 63 and the region within the pattern region 63 that is separated from the peripheral edge 64 a of the opening portion of the hole portion 64 formed in the single crystal silicon layer 62. The reinforcing portion 67 ′ is formed so as to surround the opening and is continuous with the support portion 65 ′. The box layer 65 b exposed between the reinforcing portions 67 ′ by etching the support substrate 65 a is etched from the main surface 61 b side of the substrate 61 in a subsequent process in order to expose the hole 64.

The etching of the hard mask material layer 71b can be performed by wet etching or dry etching similarly to the etching of the hard mask material layer 71a.
Further, the etching of the support substrate 65a can be performed by wet etching or dry etching similarly to the etching of the single crystal silicon layer 62.

Next, the resin layer 81 and the resist pattern 85 are removed (FIG. 20C). For removal of the resin layer 81 and the resist pattern 85, an organic solvent may be used, or ashing such as oxygen plasma treatment may be used. As the organic solvent, for example, a registry mover can be used. After removing the resin layer 81 and the resist pattern 85 using a registry mover, the organic substances remaining on the exposed hard masks 71'a and 71'b and the surface of the box layer 65b exposed at the opening of the hole 64 are removed. You may perform SPM washing | cleaning in order to remove. The SPM cleaning is also referred to as sulfuric acid hydrogen peroxide water cleaning. For example, an example in which a chemical solution mixed at H ₂ O ₂ : H ₂ SO ₄ = 3: 1 is heated to 70 ° C. to 80 ° C. can be used. It is a cleaning method that is effective in removing organic substances by utilizing a strong oxidizing action. After the SPM cleaning, the substrate may be dried by IPA drying. Such removal of the resin layer 81 and the resist pattern 85 may be performed in the same process or in different processes.

Next, the hole 64 is exposed by etching the box layer 65b. In the present embodiment, the depth of the hole 64 exposed in this manner corresponds to the thickness of the single crystal silicon layer 62 as described above, and is a desired depth within a range of 1 μm to 30 μm. ing. Etching of the box layer 65b can be performed by wet etching or dry etching similarly to the etching of the hard mask material layer 71a. The hard mask 71'b may be removed simultaneously with the etching of the box layer 65b. Further, the hard mask 71'a and the hard mask 71'b may be removed simultaneously with the etching of the box layer 65b.
Further, the step of removing the resin layer 81 may be performed after the hole layer 64 is exposed by etching the box layer 65b exposed between the reinforcing portions 67 ′.

By removing the hard masks 71'a and 71'b and the box layer 65b, a charged particle beam exposure mask 21 as shown in FIGS. 3 and 4 is obtained. SPM cleaning, APM cleaning, and hydrofluoric acid cleaning can be performed on the charged particle beam exposure mask 21 thus manufactured. Further, after cleaning, the mask may be dried by IPA drying. Here, the APM cleaning is also referred to as ammonia hydrogen peroxide water cleaning. For example, a chemical solution mixed with ammonia (NH ₄ OH): H ₂ O ₂ : H ₂ O = 1: 2: 5 is set to 70 ° C. to 80 ° C. An example of heating and use can be given, and it is a cleaning method effective in removing organic substances and insoluble particles. In such cleaning, the charged particle beam exposure mask 21 is prevented from being distorted by the reinforcing portion 27, and deformation of the thin plate portion 22, breakage of the opening portion 24, and the like are prevented.

  In addition, the charged particle beam exposure mask 51 shown in FIGS. 17 and 18 is the manufacturing method described above except that the etching conditions in the step of etching the support substrate 65a shown in FIG. (See FIGS. 19 and 20).

  In the method for manufacturing a charged particle beam exposure mask described above, an SOI substrate is used as a substrate, but the substrate to be used is not limited to an SOI substrate, and examples thereof include a silicon substrate, silicon nitride, silicon carbide, and silicon oxide. A silicon compound substrate, a compound semiconductor substrate such as gallium arsenide, a carbon substrate such as diamond-like carbon, a sapphire substrate, a metal substrate such as stainless steel, aluminum, or chromium can be used, and a desired material including these substrate materials A laminate made of a composite material selected from the above can be used as the substrate. When a laminated body made of a composite material is used as a substrate, the laminated body includes a layer for forming the thin plate portion 22 of the charged particle beam exposure mask 21 and a layer for forming the support portion 25 and the reinforcing portion 27. It is possible to perform selective etching, and it is sufficient that the formed thin plate portion 22 is a self-supporting thin film (membrane) and the thin plate portion 22 can maintain the state having the opening 24, for example, two layers. It can be a structure. Moreover, in order to give etching selectivity between the layer for constituting the thin plate portion 22 and the layer for constituting the support portion 25 and the reinforcing portion 27, the laminate may have a structure of three or more layers. When such a laminate is used, a charged particle beam exposure mask is formed in the same manner as when the above-described SOI substrate is used by setting etching conditions according to the etching selectivity of the layers constituting the laminate. Can be manufactured. In the present invention, the phrase “etching selectivity between different layers and materials” means that the etching rate may be different when etching is performed under the same conditions.

FIG. 21 is a process diagram for explaining another embodiment of the method for producing a charged particle beam exposure mask of the present invention. In this embodiment, instead of an SOI substrate, a substrate made of a single material such as a silicon substrate, a silicon compound substrate, a compound semiconductor substrate, a carbon substrate, a sapphire substrate, or a metal substrate is used as the substrate.
First, the pattern region 63 is defined on one main surface 61a of the substrate 61, the hard mask material layer 71a is formed on the main surface 61a of the substrate 61, and the hard mask material layer 71b is formed on the main surface 61b of the substrate 61. To do. The hard mask material layers 71a and 71b are formed using a material that functions as an etching resist when the substrate 61 is etched. Next, a resist pattern is formed on the hard mask material layer 71a, the hard mask material layer 71a is etched using this resist pattern as a mask to form a hard mask 71'a, and the substrate 61 is formed using this hard mask 71'a as a mask. Is etched (FIG. 21A). By this etching, a hole 64 is formed in the substrate 61. The depth of the hole 64 is equal to or greater than the thickness of the thin plate portion 22 of the charged particle beam exposure mask 21 described above.

  Next, a resin layer 81 is formed so as to cover the hole 64, and a resist pattern 85 is formed on the hard mask material layer 71b. The resist pattern 85 has an opening 85 a at a position facing the hole 64. Thereafter, the hard mask material layer 71b is etched using the resist pattern 85 as a mask to form a hard mask 71'b, and the substrate 61 is etched using the hard mask 71'b as a mask (FIG. 21B). This etching is performed so that the hole 64 is exposed and the depth D of the hole 64 is within a range of 0.1 μm to 30 μm. Thereby, a frame-shaped support portion 65 and a reinforcement portion 67 located outside the pattern region 63 are formed. The reinforcing portion 67 is located in the pattern region 63 so as to surround the opening portion of the hole portion 64 in a region separated from the peripheral edge 64 a of the opening portion of the exposed hole portion 64.

Next, the resin layer 81 and the resist pattern 85 are removed, and the hard masks 71'a and 71'b are further removed (FIG. 21C). Thereby, a charged particle beam exposure mask 51 as shown in FIGS. 3 and 4 is obtained.
The above-described embodiment of the method for manufacturing a charged particle beam exposure mask is an exemplification, and the present invention is not limited to such an embodiment.

  The present invention can be used in various manufacturing processes including processes using charged particle beam irradiation and exposure.

11, 21, 21 ′, 21 ″, 31, 41, 51... Charged particle beam exposure mask 12, 22, 32, 42... Thin plate portions 13, 23, 33, 43. Openings 14p, 24p, 34p, 44p ... Peripheries of the openings 15, 25, 35, 45 ... Support portions 17, 27, 37, 47 ... Reinforcement portions 61 ... Substrate 63 ... Pattern regions 64 ... Hole portions 64a ... Hole portions Periphery of opening 65, 65 '... support part 67, 67' ... reinforcement part

Claims (14)

A thin plate portion having a plurality of openings in the pattern region and having a thickness in the range of 0.1 μm to 30 μm;
A frame-shaped support portion which is one surface of the thin plate portion and supports the outside of the pattern region;
A reinforcing portion that is located so as to surround the opening portion and is continuous with the support portion in a region within the pattern region of the one surface of the thin plate portion that is separated from a peripheral edge of the opening portion; A charged particle beam exposure mask provided.   The charged particle beam exposure mask according to claim 1, wherein the reinforcing portion is positioned so as to surround the opening in a region separated from a peripheral edge of all the openings.   3. The charged particle beam exposure mask according to claim 1, wherein a distance at which the reinforcing portion is separated from a peripheral edge of the opening is 1 μm or more.   The charged particle beam exposure mask according to any one of claims 1 to 3, wherein a corner portion present in a contour shape in plan view of a portion surrounding the opening in the reinforcing portion is round.   The charged particle beam exposure mask according to claim 4, wherein the curvature radius of the round shape is in a range of 1 μm to 100 μm.   6. The charged particle beam exposure mask according to claim 4, wherein a radius of curvature of the round shape is equal to a distance at which the reinforcing portion is separated from a peripheral edge of the opening. 7.   The charged particle beam exposure mask according to claim 1, wherein the thin plate portion, the support portion, and the reinforcing portion are made of a material having etching selectivity. The thin plate portion is a layer made of silicon,
The reinforcing portion is a composite of a layer made of silicon oxide and a layer made of silicon, and is located in the order of the layer made of silicon oxide and the layer made of silicon from the thin plate portion side. 8. The charged particle beam exposure mask according to any one of 7 above.   The charged particle beam exposure mask according to claim 1, wherein the thin plate portion is a layer made of silicon nitride, silicon carbide, gallium arsenide, diamond-like carbon, sapphire, or metal. Defining a pattern region on one principal surface of the substrate, and forming a hole in the substrate of the pattern region;
Forming a resin layer on the substrate so as to cover the hole;
The substrate is etched with a desired pattern from the main surface side facing the one main surface of the substrate until the hole is exposed, and a frame-shaped support portion positioned outside the pattern region; and the pattern It is located in a region that is spaced from the periphery of the opening of the exposed hole and surrounds the opening, forms a reinforcing portion that is continuous with the support, and is exposed. Setting the depth of the hole to a desired depth within a range of 0.1 μm to 30 μm;
Removing the resin layer, and a method for producing a charged particle beam exposure mask.   The method for producing a charged particle beam exposure mask according to claim 10, wherein the resin layer has a thickness in a range of 5 μm to 30 μm.   The method for manufacturing a mask for charged particle beam exposure according to claim 10 or 11, wherein the substrate is an SOI substrate in which a silicon layer is laminated via a silicon oxide layer.   12. The substrate according to claim 10, wherein the substrate is a single substrate selected from the group consisting of silicon, silicon compound, compound semiconductor, carbon, sapphire, and metal, or a stacked substrate in which two or more are stacked. The manufacturing method of the mask for charged particle beam exposure of description.   The method for producing a charged particle beam exposure mask according to claim 13, wherein the multilayer substrate is a substrate obtained by laminating two or more materials having etching selectivity.

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