JP2001007005A - Aperture for electron beam lithography, mask holder, and electron beam exposure mask using them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron beam exposure mask which is free of contamination and on which an aperture for electron beam lithography and a mask holder are aligned with each other with superior accuracy. SOLUTION: An aperture 10 for electron beam lithography, in which a transfer mask opening pattern 5a of a transfer mask, a support frame 1a, a transfer mask opening section 7, a holding frame 1b, and a recessed section pattern 8 for positioning formed between the frames 1a and 1b is manufactured by working a laminated silicon substrate. A projecting section pattern 21 for positioning and a conductive layer 23 are formed on the holding member 21 of a mask holder 20. Then an electron beam exposure mask 100 is obtained by pasting an aperture 10 to the mask holder 20, using the projecting section pattern 21 as a guide and adhering and fixing the holding frame 1b of the aperture 10 to the holding member 21 of the mask holder 20 through pressing and heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam drawing aperture and a mask holder used for electron beam exposure, and an electron beam exposure mask manufactured using the same.

[0002]

2. Description of the Related Art Recently, in the manufacture of semiconductor devices such as LSIs,
An electron beam lithography system with excellent ultrafine pattern processability is used, and a multi-shot lithography system has been proposed to improve throughput, and an electron beam lithography aperture made of silicon-based material is fixed to a mask holder. An electron beam exposure mask is used by setting it in an electron beam exposure apparatus. Hereinafter, a conventional electron beam exposure mask 200 using the electron beam writing aperture 30 and the mask holder 40 will be described. Here, FIG.
3A is a schematic cross-sectional view showing an example of a conventional electron beam writing aperture 30, FIG. 3B is a schematic cross-sectional view of a mask holder 40, and FIG. 1 is a schematic cross-sectional view of a conventional electron exposure mask 200 showing a state in which the aperture 30 for use is set on a mask holder 40. 4A to 4H are schematic sectional views showing the steps of manufacturing the electron beam writing aperture 30 in the order of steps.

First, a bonded silicon substrate 31 is prepared by bonding a single crystal silicon wafer 21 and a single crystal silicon wafer 23 having a plane orientation of (100) with a silicon oxide film 22 (see FIG. 4A). A photosensitive layer is formed on a single-crystal silicon wafer 23 and patterned to form a multi-layered resist pattern 24 (FIG. 4B).
reference).

[0004] Next, the resist pattern 2 of the multi-faced
Using the mask 4 as a mask, the single crystal silicon wafer 23 is etched by dry etching to a depth reaching the silicon oxide film 22 to form a transfer mask pattern 25 (see FIG. 4C).

Next, CVD (Chemical Vap)
or Deposition) to 800
By heating to a temperature of not less than ° C., a silicon nitride film 26 having a predetermined thickness is formed as a wet etching protection film on both surfaces of the bonded silicon substrate 31 (see FIG. 4D).

Next, the silicon nitride film 26 formed on the surface of the single crystal silicon wafer 21 is patterned to form wet etching mask patterns 26a and 26b for forming a transfer pattern opening (FIG. 4E). reference).

Next, the mask patterns 26a and 26b for wet etching are stuck on a glass substrate with a sealant such as wax, and the mask patterns 26a and 26b are put in a KOH etching solution heated to 70 ° C.
Single crystal silicon wafer 2 using 6a and 26b as masks
1 is anisotropically etched for a predetermined time to form a transfer mask pattern opening 27, a support frame 21a, and a holding frame 21b (see FIG. 4F).

Next, the silicon nitride film 26 and the mask patterns 26a and 26b for wet etching are removed by etching with hot phosphoric acid at 170 ° C. (see FIG. 4G).

Next, the silicon oxide film 22 between the transfer mask pattern 25 and the transfer mask pattern opening 27 is removed by etching with hydrofluoric acid to form a transfer mask opening pattern 25a and an electron beam writing aperture. 30 (see FIG. 2 (h)).

On the other hand, a separately prepared mask holder 40
A conductive layer 42 made of a metal foil such as indium is placed on the holding member 41, and the electron beam drawing aperture 30 is pressurized and heated to melt the conductive layer 42, thereby forming an electron beam drawing layer. The holding frame 21b of the aperture 30 and the holding member 41 of the mask holder 40 are bonded and fixed. (FIG. 3
(See (b) and (c)).

Further, an aperture 30 for electron beam writing is provided.
Then, a conductive film such as Pt or Pd is formed on the mask holder 40 to obtain the electron beam exposure mask 200 (see FIG. 3C). When the aperture is used as an electron beam exposure mask, the conductive film is used to prevent charged particles from being charged on the aperture and prevent damage such as melting and distortion of the aperture.

In the above manufacturing method, when the electron beam writing aperture 30 is adhered and fixed to the mask holder 40, the electron beam writing aperture 30 is displaced on the holding member 41 of the mask holder 40, and the electron beam exposure There is a problem that the mask yield of the mask is reduced.

Further, an aperture 30 for drawing an electron beam is provided.
Is adhered and fixed to the mask holder 40, the conductor layer 42 formed on the holding member 41 of the mask holder 40.
Is heated and melted, protrudes into the area of the transfer mask opening pattern 25a, and the electron beam writing aperture 30 is contaminated, which causes problems such as a reduction in the mask yield of the electron beam exposure mask.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an electron beam exposure mask which is free from mask contamination and has excellent alignment accuracy between an electron beam drawing aperture and a mask holder. The purpose is to:

[0015]

According to the present invention, there is provided an electron beam exposure mask comprising an electron beam writing aperture fixed to a mask holder. At least one or more positioning patterns are provided on the aperture and the mask holder, and the electron beam writing aperture and the mask holder are stuck together by using the positioning patterns as a guide, and are fixed by heating and pressing. This is an electron beam exposure mask.

According to a second aspect of the present invention, there is provided the aperture for electron beam lithography according to the first aspect, wherein the positioning pattern has a concave shape.

According to a third aspect of the present invention, there is provided the mask holder according to the first aspect, wherein the positioning pattern has a convex shape.

Further, according to a fourth aspect of the present invention, a conductive layer is formed of a conductive metal foil or a conductive paste on a bonding surface outside the positioning pattern having the convex shape. Claim 1 or 3
It is the mask holder described.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a schematic sectional view showing an embodiment of the aperture 10 for electron beam writing according to the present invention, and FIG. 1B is a schematic sectional view showing an embodiment of a mask holder 20 according to the present invention. FIG. 1C is a schematic cross-sectional view showing one embodiment of an electron beam exposure mask 100 showing a state in which an electron beam writing aperture 10 is fixed to a mask holder 20, and FIGS. h) is a schematic cross-sectional view showing the steps of manufacturing the electron beam writing aperture of the present invention in the order of steps.

Aperture 10 for electron beam writing according to the present invention
Is composed of a transfer mask opening pattern 5a, a support frame 1a, a transfer mask pattern opening 7 and a holding frame 1b by processing a bonded silicon substrate 11, and the support frame 1a and the holding frame 1b at both ends of the electron beam writing aperture are formed. The tapered positioning recessed pattern 8 is formed between them (see FIG. 1A).

In the mask holder 20 of the present invention, a positioning projection pattern 21 is formed on a holding member 21, and a conductive layer 23 for bonding and fixing an electron beam writing aperture is provided outside the positioning projection pattern 21. (See FIG. 1B).

Further, in the electron beam exposure mask 100 of the present invention, the electron beam writing aperture 10 is bonded by using the positioning convex pattern 22 on the holding member 21 of the mask holder 20 as a guide, and is pressed and heated. The holding frame 1b of the electron beam writing aperture 10 and the holding member 21 of the mask holder 20 are bonded and fixed (see FIG. 1C).

First, a bonded silicon substrate 11 in which a single crystal silicon wafer 1 and a single crystal silicon wafer 3 having a plane orientation of (100) are bonded with a silicon oxide film 2.
(See FIG. 2A), and a single-crystal silicon wafer 1
A photosensitive layer is formed on the surface, and a patterning process is performed to form a multi-layered resist pattern 4 (see FIG. 2B).

Next, using the resist pattern 4 as a mask, the single-crystal silicon wafer 1 is etched to a depth reaching the silicon oxide film 2 by dry etching to form a transfer mask pattern 5 (FIG. 2).
(C)).

Next, CVD (Chemical Vap)
or Deposition) to 800
The silicon nitride film 7 is heated on both sides of the bonded silicon substrate 11 as a protection film for wet etching.
Is formed (see FIG. 2D).

Next, the silicon nitride film 6 formed on the single crystal silicon wafer 1 is patterned to form wet etching mask patterns 6a and 6b for forming a transfer pattern opening (FIG. 2 ( e)).

Mask pattern 6a for wet etching
And 6b are stuck on a glass substrate with a sealing material such as wax, put in a KOH etching solution heated to 70 ° C., and wet etching mask patterns 6a and 6b
The mask is used as a mask to anisotropically etch the single crystal silicon wafer 1 for a predetermined time to form a transfer mask pattern opening 7 and a positioning recess pattern 8 between the support frame 1a and the holding frame 1b (FIG. 2 (f) )reference).

The shape of the positioning concave pattern 8 can be set to a rod-shaped, pin-shaped or line-shaped concave pattern, and is appropriately selected depending on the positioning convex pattern 22 of the mask holder 20.

The positioning recess pattern 8 has the same taper angle (plane orientation as (10
54.7 when the single crystal silicon wafer of 0) is used
Degree) is formed, the mask holder 20
The pattern interval between the wet etching mask patterns 6a and 6b is set in accordance with the shape of the positioning convex pattern 22.

Next, the silicon nitride film 6 and the mask patterns 6a and 6b for wet etching are removed by etching with hot phosphoric acid at 170 ° C. (see FIG. 2 (g)).

Next, the silicon oxide film 2 between the transfer mask pattern 5 and the transfer mask pattern opening 7 is removed by etching with hydrofluoric acid and penetrated to form a transfer mask opening pattern, and the electron beam writing aperture 10 is formed. (See FIG. 2 (h)).

On the other hand, the positioning convex pattern 2 formed on the holding member 21 of the mask holder 20 separately manufactured.
A conductive layer 23 is formed on the outside of the substrate 2 with a metal foil such as indium or a conductive paste (see FIG. 1B), and the positioning projection pattern 22 of the mask holder 20 is used as a guide for the electron beam writing aperture 10. Are bonded and pressed and heated to bond and fix the holding frame 1b of the electron beam writing aperture 10 and the holding member 21 of the mask holder 20 (see FIG. 1C). Here, the conductive layer formed of a metal foil such as indium is heated and melted and adhered and fixed, but the conductive layer formed of a conductive paste or the like is heated and pressed to cure the resin of the conductive paste. Glued and fixed.

Next, a conductive film such as Pt or Pd is formed on the electron beam writing aperture 10 and the mask holder 20 to obtain the electron beam writing aperture 100 of the present invention (see FIG. 1C). This conductive film serves to prevent charged particles from being charged in the electron beam writing aperture 10 during electron beam exposure, thereby preventing damage such as melting and distortion of the aperture.

[0034]

According to the electron beam exposure mask of the present invention, the alignment accuracy when the electron beam drawing aperture is adhered and fixed to the mask holder is improved, and the electron beam exposure mask is set in the electron beam exposure apparatus until the electron beam exposure is performed. Start-up adjustment time is greatly reduced. In addition, the conductive layer does not protrude into the transfer mask pattern generated when the electron beam writing aperture is bonded and fixed to the mask holder, so that a high-quality electron beam exposure mask can be obtained, and the manufacturing yield can be improved.

[Brief description of the drawings]

FIG. 1A is a schematic sectional view showing an embodiment of an electron beam writing aperture 10 according to the present invention. (B)
FIG. 1 is a schematic cross-sectional view showing a configuration of an embodiment of the mask holder 20 of the present invention. FIG. 1C is a schematic cross-sectional view showing one embodiment of the electron beam exposure mask 100 showing a state in which the electron beam writing aperture 10 is fixed to the mask holder 20.

FIGS. 2A to 2H are schematic sectional views showing the steps of manufacturing the electron beam writing aperture 10 of the present invention in the order of steps.

FIG. 3A is a schematic cross-sectional view showing an example of a conventional electron beam writing aperture 30. FIG. 2B is a schematic cross-sectional view illustrating an example of a conventional mask holder 40. 3C is a schematic cross-sectional view illustrating an example of the electron beam exposure mask 200 in a state where the electron beam writing aperture 30 is fixed to the mask holder 40. FIG.

FIGS. 4A to 4H are schematic cross-sectional views showing the steps of manufacturing a conventional aperture 30 for electron beam writing.

[Explanation of symbols]

1, 21 single crystal silicon wafer 1a, 21a support frame 1b, 21b holding frame 2, 22 silicon oxide film 3, 23 single crystal silicon wafer 4, 24 resist pattern 5, 25 Transfer mask pattern 5a, 25a Transfer mask opening pattern 6, 26 Silicon nitride film 6a, 6b, 26a, 26b Resist pattern for wet etching 7, 27 Transfer mask pattern opening 8 Positioning Recess pattern for electron beam 10, 30 ... aperture for electron beam drawing 11, 31 ... bonded silicon substrate 20, 40 ... mask holder 21, 41 ... holding member 22 ... convex pattern for positioning 23, 42 ... conductive Body layer 100, 200 ... E-beam exposure mask

Continued on the front page (72) Inventor Hironobu Sasaki 1-1-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Toshio Konishi 1-1-1, Taito, Taito-ku, Tokyo Toppan Printing Stock In-house F term (reference) 2H095 BA08 BB02 BC21 BC30 5F056 AA22 EA04 FA05

Claims (4)

[Claims] 1. An electron beam exposure mask comprising an electron beam writing aperture fixed to a mask holder, wherein at least one positioning pattern is provided on the electron beam writing aperture and the mask holder, and the positioning pattern is provided on the mask. An electron beam exposure mask, wherein the electron beam writing aperture and the mask holder are bonded together as a guide, and are fixed by heating and pressing. 2. The aperture according to claim 1, wherein the positioning pattern has a concave shape. 3. The mask holder according to claim 1, wherein said positioning pattern has a convex shape. 4. A conductive layer formed of a conductive metal foil or a conductive paste on a bonding surface outside the positioning pattern having the convex shape. Mask holder.