JP2001068405A - Transfer mask with drive mechanism and electron beam projection exposure apparatus having the same - Google Patents

Abstract

(57) [Object] To provide a transfer mask having a mechanism capable of correcting distortion generated in a membrane constituting a transfer mask, and an electron beam projection exposure apparatus provided with the transfer mask. A membrane, an outer peripheral frame for fixing the outer periphery of the membrane and supporting the same, and supporting the membrane,
A transfer mask including a support for dividing the support frame into a plurality of small areas, wherein the outer peripheral frame is provided with an outer support, an inner support, and a drive unit provided between the outer support and the inner support. And the driving unit includes a control unit that controls a driving amount,
A transfer mask with a driving mechanism, wherein a reinforcing frame for reinforcing the outer supporting portion is joined to the outer supporting portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a transfer mask with a driving mechanism used in a charged particle beam reduction transfer apparatus and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of semiconductor integrated circuit elements, charged particle beams (hereinafter, referred to as X-rays, electron beams, ion beams, etc.) have been developed in order to improve the resolution of an optical system limited by the diffraction limit of light. An exposure method (lithography technique) using a charged particle beam (hereinafter simply referred to as a charged particle beam) has been developed. Among them, electron beam exposure, in which a pattern is formed using an electron beam, is characterized in that a fine pattern of 1 μm or less can be formed because the electron beam itself can be reduced to several Å (angstrom). is there.

However, since the conventional electron beam exposure method is a one-stroke writing method, the finer the pattern, the more the electron beam must be drawn with a narrower electron beam, the longer the drawing time, and the cost of device production. It was not used for exposure of mass-produced wafers. Therefore, there has been proposed a charged particle beam reduction transfer apparatus which irradiates a transfer mask having a predetermined pattern with an electron beam and reduces and transfers a pattern in the irradiation range to a wafer by a projection lens.

In order to project a circuit pattern, a transfer mask on which the circuit pattern is drawn is required. As a transfer mask, as shown in FIG. 9A, there is no through-hole, and a scattered transmission transfer mask 21 in which a scatterer pattern 24 is formed on a membrane 22, and as shown in FIG. A membrane 3 having a thickness enough to scatter electron beams
2. A scattering stencil transfer mask 31 having a through-hole pattern 34 formed thereon is known.

[0005] In these, a large number of small regions 22a and 32a each having a pattern to be transferred to the sensitive substrate on the membranes 22 and 32 are divided by a boundary region where no pattern exists, and a support 23 is provided at a portion corresponding to the boundary region. , 33
Is provided. In the scattering stencil transfer mask, the membrane is made of a silicon membrane having a thickness of about 2 μm, and the membrane is provided with an opening (corresponding to a pattern to be transferred to a sensitive substrate) through which an electron beam passes.

That is, since the area exposed by one electron beam is about 1 mm square, the pattern to be transferred to the area of one chip (one chip semiconductor) of the sensitive substrate is placed in this small area of 1 mm square. Are formed, and a large number of these small areas are spread. Therefore, the pattern transfer method using charged particle beam,
As shown in FIG. 9C, each of the small regions 22a and 32a is scanned stepwise by a charged particle beam, and a pattern corresponding to the opening of each small region or the arrangement of the scatterer is formed by an optical system (not shown). Since it is a method in which the transfer mask is reduced and transferred to the sensitive substrate 27, the pattern for each small area 22a of the transfer mask is connected on the sensitive substrate 27.

Further, from the viewpoint of reinforcing the strength of the transfer mask, facilitating the handling of the transfer mask in a transfer system such as a mask stage, etc., as shown in FIG.
A transfer mask for charged particle beam exposure with a reinforcing frame in which a reinforcing frame 36 having a higher strength is joined to the lower surface of the substrate has been proposed. As a method for joining the transfer mask for charged particle beam exposure and the reinforcing frame 36, a eutectic joining method, an anodic joining method, a joining method using an adhesive, a mechanical joining method, or the like is used.

[0008]

However, the distortion generated when the reinforcing frame 36 and the outer peripheral frame 35 are joined is distorted up to the membrane 32, and when a pattern is formed on such a membrane 32, the pattern is formed. It will be distorted. Alternatively, if such bonding is performed after forming a fine pattern on the membrane 32, the fine pattern will be distorted.

Using such a transfer mask, an accurate pattern cannot be transferred to a photosensitive substrate. Accordingly, the present invention has been made in view of such a conventional problem, and a transfer mask having a mechanism capable of correcting a distortion generated in a membrane constituting the transfer mask, and an electronic device including the same. An object of the present invention is to provide a line projection exposure apparatus.

[0010]

Means for Solving the Problems As a result of intensive studies, the present inventor has arrived at the present invention. The present invention firstly provides a `` transfer mask comprising a membrane, an outer peripheral frame for fixing the outer periphery of the membrane and supporting the same, and supporting the membrane, and supporting columns for dividing the membrane into a plurality of small areas. The outer frame is
An outer support section, an inner support section, and a drive section provided between the outer support section and the inner support section, wherein the drive section includes a control section for controlling a drive amount, and In the department,
A transfer mask with a driving mechanism, characterized in that a reinforcing frame for reinforcing the transfer mask is joined, is provided.

The present invention also provides a second aspect of the present invention, wherein the driving section is electrically or electrostatically driven.
The present invention provides a transfer mask with a driving mechanism according to claim 2. In addition, the present invention provides a third aspect, wherein the driving section includes a first spring structure section connected to the outer support section, a second spring structure section connected to the inner support section, and a first spring structure section. An insulating portion provided between the second spring structure portion and the second spring structure portion, wherein the first spring structure portion is a part of a conductive divided region provided on the outer support portion; The structure portion is a part of a conductive divided region provided on the inner support portion, and the transfer mask with a driving mechanism according to claim 1 (claim 3) is provided.

Further, the present invention is a fourth aspect of the present invention that provides an illumination optical system for irradiating a transfer mask disposed at a predetermined position with an electron beam, a stage of the transfer mask, and an electron beam from the transfer mask. 2. An electron beam projection exposure apparatus comprising: a projection imaging optical system configured to project and form a pattern formed on a mask onto a substrate disposed at a predetermined position; and a stage of the substrate. 4. An electron beam projection exposure apparatus (claim 4), which is the transfer mask with a driving mechanism according to any one of (1) to (3).

The present invention is also directed to a fifth aspect of the present invention wherein an electron beam is irradiated to each small area of a transfer mask having a plurality of small areas made of a membrane, and a pattern formed in each small area is sequentially transferred. In the exposure method, the transfer mask includes a plurality of driving units capable of minutely operating the membrane, and is formed in a small area of the transfer mask by operating a plurality of driving units provided on the transfer mask. An electron dew ray method (claim 5) to be performed after correcting the distortion of the given pattern to within an allowable value.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A transfer mask with a driving mechanism according to an embodiment of the present invention and a method for manufacturing the same will be described below with reference to the drawings. FIG. 1 is a schematic top view and a schematic cross-sectional view of a transfer mask with a driving mechanism according to an embodiment.

The transfer mask with a driving mechanism according to the embodiment comprises a membrane 1, an outer peripheral frame 2 for fixing the outer periphery of the membrane 1 and supporting the same, and a column for supporting the membrane 1 and dividing it into a plurality of small areas 3. 4, wherein the outer peripheral frame 2 comprises an outer support portion 5, an inner support portion 7, and a drive portion 6 provided between the outer support portion 5 and the inner support portion 7. Have been.

The outer supporting portion 5 of the transfer mask is reinforced by a reinforcing frame 9, and a pad 10 is provided on the back surface of the reinforcing frame 9.
The wiring 8 is connected. FIG. 2 is a schematic enlarged view of the vicinity of the drive unit of the transfer mask according to the embodiment. Each drive section 6 includes a first spring structure section 5a connected to the outer support section 5, a second spring structure section 7a connected to the inner support section 7, a first spring structure section 5a, and a second spring structure section. 7a, and is provided with an insulating section 6a, and 12 driving sections including a first driving section 6 (1) to a twelfth driving section 6 (12) are provided.

The first drive unit 6 (1) to the twelfth drive unit 6
The reference numerals of the first spring structures constituting each drive unit up to (12) are 5a (1) to 5a (12), and the reference numerals of the second spring structures are 7a (1) to 7a (12). In this case, the symbols of the insulating portions are 6a (1) to 6a (12). Further, the first spring structure portion 5a (1) of the first driving portion 6 (1) connected to the outer support portion 5 is provided in one of the conductive divided regions (M) provided in the outer support portion 5. And the second spring structure portion 7a of the first drive portion 6 (1) connected to the inner support portion 7
(1) is a part of the conductive divided region (A) provided in the inner support portion 7.

FIG. 3 is a view showing the arrangement of the conductive areas and the drive section of the transfer mask of the embodiment. First drive unit 6
(1) The symbols of the conductive divided regions provided on the outer support portion 5 corresponding to the twelfth drive portion 6 (12) are A
~ L. In addition, wirings 8 (1 to 12) for transmitting a drive signal are provided in the conductive divided regions (A to L) provided on the outer support portion.

Therefore, as shown in FIG. 2 (b), when a voltage is applied to the conductive divided regions provided on the outer support portions, the first and second conductive spring structures and the second spring structure are provided. Electrostatic force is generated between the two parts, and an attractive force is generated on both sides. FIGS. 4A to 4J are views of the state of the operation of the inner support portion by the drive mechanism provided in the conductive divided region when viewed from above the transfer mask.

When a voltage is applied to the conductive divided region (ADGJ) of the transfer mask shown in FIG. 3, the inner support portion 7 (therefore, the membrane 1) rotates clockwise in the drawing (FIG. 4A), When a voltage is applied to the conductive divided region (CFIL), the inner support portion 7 (therefore, the membrane 1) rotates counterclockwise on the drawing. Rotation angle is about 3μde
g to 3 mdeg, and can be controlled with an accuracy of about 1 μdeg.

When a voltage is applied to the conductive divided area (ABC), the inner support portion 7 (therefore, the membrane 1) operates upward in the drawing (FIG. 4C), and the conductive divided area (GHI) ), The inner support 7 (and thus the membrane 1) operates downward in the drawing (FIG. 4d), and when a voltage is applied to the conductive divided region (IKL), Then, the inner support 7 (hence the membrane 1) on the left side operates (FIG. 4e), and when a voltage is applied to the conductive divided area (DEF), the inner support 7 (hence the membrane) on the right side in the drawing. Works (FIG. 4f).

The operable distance is about 1 nm to 1 μm, and can be controlled with an accuracy of about 1 nm. When a voltage is applied to the conductive divided region (GHIJKL) of the transfer mask, the inner support operates at the lower left in the drawing (FIG. 4g), and the conductive divided region (DEFGHI)
When a voltage is applied to i), the inner support portion 7 (and thus the membrane 1) operates at the lower right in the drawing (FIG. 4h), and when a voltage is applied to the conductive divided region (ABCDEF), The inner support 7 (hence, the membrane 1) operates at the upper right in the drawing (FIG. 4i), and when a voltage is applied to the conductive divided region (ABCJKL), the inner support 7 moves to the upper left in the drawing. (Hence, the membrane 1) operates (FIG. 4j).

The operable distance is from about 1.4 nm to about 1.4.
It is about μm and can be controlled with an accuracy of about 1.4 nm. Next, a method of manufacturing the transfer mask with a driving mechanism according to the embodiment will be described. 5 to 7 are views showing a process of manufacturing the transfer mask with a driving mechanism according to the embodiment.

First, an SOI (Silicon on Insulater) substrate including a supporting silicon substrate 11, a silicon oxide layer 12, and a silicon active layer 13 manufactured by a general manufacturing method is prepared, and the supporting silicon substrate (insulating property) of the SOI substrate is prepared. 1
1. Conductive regions 14 (1 to 12) and 15 are formed in FIG. 1 (FIG. 5a). A conductive region is formed by ion implantation or thermal diffusion using a mask having openings in predetermined regions. ,
Impurities (P, B) in predetermined regions of the supporting silicon substrate 11
By doping.

A mask material such as a resist is formed on the supporting silicon substrate 11, a predetermined pattern is formed, and an etching mask 16 having a predetermined pattern is formed (FIG. 5B). The supporting silicon substrate 11 on which the conductive regions 14 and 15 are formed is etched by an anisotropic dry etching method according to the opening pattern formed on the etching mask, and the outer supporting portion 17, the driving portion 18, and the inner supporting portion are etched. 1
9. Form the pillar 20.

At this time, the etching of the supporting silicon substrate 11 is performed up to the silicon oxide layer 12 due to the difference in the etching selectivity between silicon and silicon oxide (FIG. 6).
a). Next, the silicon oxide layer 12 exposed at the opening
Is removed with hydrofluoric acid, the silicon active layer 13 becomes a silicon membrane 13a, and a blank for a transfer mask is completed (FIG. 6B).

[0027] Membrane 13 of blank for transfer mask
A resist 60 is applied on the substrate a (FIG. 7A), a predetermined fine pattern is baked and transferred using an electron beam lithography apparatus or the like, and the resist on which the predetermined pattern is transferred is used as an etching mask 61 (FIG. 7B). The stencil transfer mask is completed by etching the membrane 13a (FIG. 7).
c).

Although the opening pattern to be transferred to the photosensitive substrate is formed on the membrane after forming the membrane, the so-called "back etch precedent process" has been described. However, the opening pattern should be transferred to the silicon active layer of the SOI substrate on the photosensitive substrate. After forming the pattern, the supporting silicon substrate and the silicon oxide layer are etched into a predetermined pattern, and the silicon active layer is formed into a membrane on which an opening pattern to be transferred to the photosensitive substrate is formed. Can obtain a similar transfer mask.

The outer support portion 17 of the transfer mask and the reinforcing frame 62 are joined by a eutectic joining method, an anodic joining method, a joining method using an adhesive, a mechanical joining method, or the like (FIG. 7D). Here, an example of a joining method by a eutectic joining method will be described.
First, a reinforcing frame 62 made of silicon is prepared. The size of the reinforcing frame 62 is larger than the inner and outer diameters of the outer support portion 17 of the transfer mask in both the inner diameter and the outer diameter, and the thickness is about 5 to 10 mm, although it depends on the radius of the reinforcing frame. is there.

The shape of the inner diameter is not limited to a circle, but may be a polygon. A gold thin film having a thickness of 200 to 500 nm is formed on a portion of the reinforcing frame to be joined to the outer supporting portion 17 by a known vacuum evaporation method or the like. The surface of the reinforcing frame 62 on which the gold thin film is formed is preferably mirror-polished from the viewpoint of adhesion and the like.

The reinforcing frame 62 thus prepared,
The outer support 17 of the charged particle beam exposure mask is joined via a thin gold film. In this bonding, the gold thin film formed on the reinforcing frame 62 is brought into contact with a portion to be bonded of the outer support portion 17 of the transfer mask, and is heated in an electric furnace at 400 ° C. for 5 hours to perform eutectic bonding of gold-silicon.

More preferably, the gold thin film formed in a ring shape is partially removed by etching or the like to form a thin piece having an area of several square millimeters, or a thin film mask having a predetermined opening is used. To form a gold flake having an area of several square millimeters. Here, the area of the gold flakes to be left and the number of gold flakes are determined by the bonding strength and the allowable strain value required after bonding.

The reinforcing frame 62 thus prepared,
The outer support portion 17 of the transfer mask for charged particle beam exposure is bonded via a gold flake. In this joining, the gold flakes formed on the reinforcing frame 62 are brought into contact with the joining portions of the outer support portion 17 of the transfer mask, and are heated in an electric furnace at 400 ° C. for 5 hours to perform eutectic joining of gold and silicon.

After joining the reinforcing frame 62 and the outer support 17 of the transfer mask blank for charged particle beam exposure manufactured by the steps shown in FIGS. 5 and 6, the membrane is applied to the membrane in accordance with the step shown in FIG. An opening pattern may be formed. Further, the reinforcing frame 6 on the back surface of the outer support portion 17 of the transfer mask is provided.
As described above, a gold thin film is formed on a portion to be bonded to the transfer mask 2 and the outer support portion 17 of the transfer mask and the reinforcing frame 63 are bonded via the gold thin film by eutectic of gold-silicon at the interface. You may. Finally, the outer support 17 of the transfer mask
Regions 14a (1) to 14a having conductivity provided in
(12) and the conductive pads 63 provided on the back surface of the outer support frame 62 are respectively bonded by wire bonding using the wiring 64 (FIG. 7D). FIG. 8 is a schematic configuration diagram of an electron beam projection exposure apparatus according to the present invention.

The electron beam projection exposure apparatus includes a stage of the transfer mask 42 according to the present invention, and an illumination optical system (an electron gun, an electron beam from the electron gun is used as a transfer mask) for irradiating the transfer mask 42 with an electron beam 51. An illumination optical system for irradiating) 41 and an electron beam 52 transmitted or passed through the transfer mask 42.
4 is composed of a projection imaging optical system 43 for projecting the image on the substrate 4 and a stage on a substrate 44.

First, the transfer mask 42 according to the present invention comprises:
Before use in an electron beam projection exposure apparatus, first, distortion of a pattern shape at a predetermined position of a membrane of a transfer mask is measured. The distortion of the pattern shape is measured, for example, using a Nikon lightwave interference coordinate measuring machine. Next, after the transfer mask 42 according to the present invention is set on the stage, the plurality of driving units provided on the transfer mask are operated based on the amount of distortion described above, whereby the plurality of inner support units provided on the transfer mask (And thus the membrane) is controlled (combination of the operations of FIG. 4 described above), and the distortion of the pattern shape at a predetermined position is corrected to within an allowable value (5 nm to 20 nm).

After the correction is completed, the electron beam 51 emitted from the illumination optical system 41 of the transfer mask is irradiated on the transfer mask 42, and the electron beam 52 transmitted or passed through the transfer mask 42 is converted into a projection image forming optical system 43. And enters the substrate 44 via the. The photosensitive substrate 44 is, for example, a silicon wafer applied to a resist, and an electron beam incident on the photosensitive substrate 44 exposes the resist. That is, the projection imaging optical system 43 projects the circuit pattern on the transfer mask 42 onto the substrate 44 in a reduced size, and as a result, can expose the resist on the substrate 44 into a fine circuit pattern.

[0038]

As described above, according to the transfer mask with a driving mechanism according to the present invention, the inner supporting portion can be moved by using the driving mechanism, and as a result, the distortion of the membrane and, consequently, the pattern shape can be reduced. The distortion can be corrected. When the transfer mask according to the present invention is applied to an electron beam projection exposure apparatus, the amount of distortion of the membrane of each transfer mask measured in advance before exposure, and thus the amount of distortion of the pattern shape can be corrected. The pattern formed on the mask can be accurately transferred to the photosensitive substrate.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a transfer mask with a driving mechanism according to the present invention.

FIG. 2 is a schematic enlarged view of the vicinity of a drive unit of a transfer mask according to the present invention.

FIG. 3 is a diagram showing an arrangement of a conductive region and a driving unit of a transfer mask according to the present invention.

FIGS. 4A to 4J are views of the operation of an inner support unit by a driving mechanism provided in a conductive divided region when viewed from above a transfer mask.

FIG. 5

FIG. 6

FIG. 7 is a view showing a process of manufacturing a transfer mask with a driving mechanism according to the present invention.

FIG. 8 is a schematic sectional view of an electron beam projection exposure apparatus according to the present invention.

9A and 9B are schematic diagrams of a scattering transmission mask, a scattering stencil mask, and a pattern transfer method using an electron beam among transfer masks used in an electron beam projection exposure apparatus. It is a schematic perspective view shown.

FIG. 10 is a schematic cross-sectional view and a schematic top view of a conventional transfer mask with a reinforcing frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Membrane 2 ... Peripheral frame 3 ... Small area 4, 20 ... Column 5, 17 ... Outer support part 6, 18 ... Driving part 7, 19 ... Inner support part 8, 64 ... wiring 9, 36, 62 ... reinforcing frame 10, 63 ... conductive pad 11 ... support silicon substrate 12 ... silicon oxide layer 13 ... silicon active layer 14, Reference numeral 15: Conductive region 16, 61: Etching mask 21: Scattering / transmission mask 22, 32: Membrane 23, 33 ... Support column 24: Scatterer pattern 27: Photosensitive substrate 31 ... scattering stencil mask 34 ... through-hole pattern 35 ... outer support part 41 ... illumination optical system 42 ... transfer mask with drive mechanism 43 ... projection imaging optical system 44 ... photosensitive Substrates 51, 52: electron beam 60: cash register Strike

Claims (5)

[Claims] 1. A transfer mask comprising: a membrane; an outer peripheral frame for fixing and supporting the outer periphery of the membrane; and a support column for supporting the membrane and dividing the membrane into a plurality of small areas. An outer supporting portion, an inner supporting portion, and a driving portion provided between the outer supporting portion and the inner supporting portion, wherein the driving portion includes a control portion for controlling a driving amount; A transfer mask with a driving mechanism, wherein a reinforcing frame for reinforcing the supporting portion is joined to the support portion. 2. The transfer mask with a driving mechanism according to claim 1, wherein said driving unit is driven electrically or electrostatically. 3. The drive unit includes a first spring structure connected to the outer support, a second spring structure connected to the inner support, a first spring structure, and a second spring structure. The first spring structure is a part of a conductive divided region provided in the outer support portion, and the second spring structure is The transfer mask with a driving mechanism according to claim 1, wherein the transfer mask is a part of a conductive divided region provided on the inner support portion. 4. An illumination optical system for irradiating a transfer mask disposed at a predetermined position with an electron beam, a stage of the transfer mask, and a pattern formed on the transfer mask by receiving an electron beam from the transfer mask. An electron beam projection exposure apparatus comprising: a projection imaging optical system configured to project an image on a substrate disposed at a predetermined position; and a stage of the substrate. The transfer mask according to claim 1, wherein An electron beam projection exposure apparatus, which is a transfer mask with a driving mechanism. 5. An electron beam exposure method for irradiating an electron beam to each small area of a transfer mask having a plurality of small areas made of a membrane and sequentially transferring a pattern formed in each small area, wherein the transfer mask Is provided with a plurality of driving units capable of minutely operating the membrane, and by operating a plurality of driving units provided on the transfer mask, a distortion of a pattern formed in a small region of the transfer mask is allowed. Electron dew ray method performed after correction within the value.