WO2004060793A1

WO2004060793A1 - Multilayer structure and method for manufacturing same, functional structure and method for manufacturing same, and mask for electron beam exposure and method for manufacturing same

Info

Publication number: WO2004060793A1
Application number: PCT/JP2003/014512
Authority: WO
Inventors: Masaki Hara
Original assignee: Sony Corporation
Priority date: 2002-12-26
Filing date: 2003-11-14
Publication date: 2004-07-22
Also published as: JP2004207625A; TW200426905A

Abstract

A first layer and a second layer at least one of which is composed of a single-crystal material are brought together at room temperature with a layer containing one or more metals, e.g. a metal film such as an Al film, interposed therebetween, thereby forming a multilayer structure. Both of the first and second layers can be composed of single crystal materials, or they may be composed of different materials. The first and second layers are, for example, single-crystal Si layers or single-crystal Si substrates. For example, a micromirror is manufactured using this multilayer structure.

Description

Description Multilayer structure, method of manufacturing the same, functional structure and method of manufacturing the same, mask for electron beam exposure, and method of manufacturing the same

The present invention relates to a multilayer structure, a method for manufacturing the same, a functional structure, a method for manufacturing the same, an electron beam exposure mask, and a method for manufacturing the same. Background art

In the field of MEMS (Microelectromechanical Systems), a SOI (Silicon On Insulator) substrate has been frequently used as a substrate for fabricating a structure having a flat surface, for example, a micromirror. Structure which is a structure having upper and lower single-crystal silicon thermal oxide film called B OX layer between the (S i) layer (S i 0 ₂ film), by processing them single crystal S i layer It is what makes.

For the processing of the single-crystal Si layer on the SII substrate described above, a dry etching method using high-density plasma, called a deep RIE (Reactive Ion Etching) method, is often used (for example, Alexandra Rick ard and Mark Mcie Characterization and optimisation of deep dry etching for MEMS applications' SPIE International Conference on "Microelectronic & MEMS Technologies", Edinburgh (UK), May 2001 and Japanese Patent Application Publication No.).

Note that Japanese Patent Application Laid-Open No. 5-2187825 discloses that a Si substrate is made porous, and a non-porous Si single crystal layer is formed on the porous substrate. A technique for bonding both Si substrates by heating the non-porous Si single crystal layer to a temperature of 450 to 900 ° C with the surface of the non-porous Si single crystal layer bonded to another substrate having a metal surface. It has been disclosed. Also, Japanese Patent Application Laid-Open No. 5-10971 discloses that the surface of the first Si substrate on which the polycrystalline Si layer is formed is in contact with the first Si substrate. There is disclosed a technique of bonding both Si substrates by performing a heat treatment at about 100 ° C. Japanese Patent Application Laid-Open Nos. 11-15035 and 110-1576 describe that two substrates are provided with a reaction layer between a metal and a metal or a semiconductor between them. A technique for manufacturing an S 0 I substrate by bonding by forming is disclosed.

However, when the single crystal Si layer of the SOI substrate is processed by the deep RIE method described above, when the etching of the single crystal Si layer is completed and the underlying SiO ₂ film is exposed, the charged Si 0 ₂ Notsuchingu phenomenon that the bottom of the bent orbit of i on the single crystal S i layer is gouged for membrane has occurred. In order to suppress this phenomenon, it is necessary to take measures such as switching the recipe of the etching process immediately before the end of the etching of the single-crystal Si layer, or installing a mechanism for preventing charge-up in the etching apparatus. Was. However, these countermeasures are problematic in that the former requires less time, but is less accurate, and the latter requires a larger initial investment and is still difficult to completely control.

In addition, when an SOI substrate is used, it is difficult to form electrical wiring on the surface of the single crystal Si layer on the side of the SiO ₂ film. Therefore, it was difficult to produce a structure utilizing both surfaces of the single-crystal Si layer.

Therefore, the problem to be solved by the present invention is to manufacture various functional structures such as micromirrors inexpensively, easily and accurately. And a method of manufacturing the same. Another object of the present invention is to provide a functional structure capable of manufacturing various types of functional structures such as micromirrors inexpensively, easily, and accurately, and a method of manufacturing the same. .

Still another object of the present invention is to provide an electron beam exposure mask capable of manufacturing an electron beam exposure mask at a low cost, easily and accurately, and a method of manufacturing the same. Disclosure of the invention

In order to solve the above-mentioned problems, a multilayer structure according to a first invention of the present invention comprises:

It is characterized in that a first layer and a second layer, at least one of which is made of a single crystal material, are joined at room temperature via a layer containing at least one kind of metal.

Here, the single crystal material includes not only a perfect single crystal but also a material that can be regarded as a substantially single crystal, such as a material containing a sub-grain boundary. Also, if one of the first and second layers is not made of a single crystal material, it is specifically a polycrystalline or amorphous material. Typical—In one example, both the first and second layers consist of a single crystal material. Here, the single crystal material is excellent as a structural material because it has extremely low internal stress, is tough, and can produce a flat layer or a substrate.

The first layer and the second layer may be made of the same material or may be made of different materials. The material of the first layer and the second layer can be selected according to the purpose of use of the multilayer structure, and basically any material can be used. If that, one of the first layer and the first layer, S i, S i have _x G e _x (was however, 0 <x≤ 1), S i C :, C ( diamond etc.), III _ V compound semiconductor (e.g., G a a s based semiconductor, a 1 G a I _n p type semiconducting material, G a n type semiconductor, etc.) consists of compounds typified by semiconductor, the other is, S i, glass (For example, Pyrex (registered trademark) glass) and ceramics. When a semiconductor is used as the material of the first layer and the second layer, the semiconductor may be non-doped or may be doped with an n-type impurity or a p-type impurity. In a typical example, at least one of the first layer and the second layer is made of single-crystal Si, and in particular, both the first layer and the second layer are made of single-crystal Si. Further, in another exemplary embodiment, at least hand of the first layer and the second layer is made of a single crystal S i, the other of the _t first and second layers of glass or ceramics If at least one needs to be processed by dry etching, the layer is made of a dry-etchable material. As the material that can be dry-etched, various materials can be used in combination with the dry-etching method to be used, and single crystal Si is one of the materials excellent in this dry-etching property.

Each of the first layer and the second layer may have a single-layer structure made of a single material or a multi-layer structure made of a plurality of layers made of the same or a plurality of materials. . Further, the first layer and the second layer may have a structure or an element formed on one or both of them.

The layer containing one or more metals sandwiched between the first and second layers typically comprises a metal or alloy. This metal or alloy can be selected according to the purpose of use of the multilayer structure, and basically any material can be used. However, dry etching resistance, electrical conductivity, The most suitable one is often selected from the viewpoint of thermal conductivity and the like. Specific examples include Al, Cu, Au, Cr, Ta, and W. Here, a low-melting-point metal such as A1 can be used because room-temperature bonding is used. The layer containing one or more metals is patterned into a predetermined shape depending on the intended use of the multilayer structure. When showing the thermal expansion coefficient of a metal exemplified above by reference, S for i that 2. is ^{4 4 X 1 0- 6 / °} C, A 1 is 2. 3 X 1 0 - ⁵ / . C, C u is 1. 4 x 1 0 one ⁵ / ° C, A u is ^{1. 4 2 X 1 0- 5} / ° C, C r is ^{8. 2 x 1 0- 6 / °} C, T a the ^{7 x 1 0- 6 /;,} W is ^{4 x 1 0- 6 / ° C} . The thermal expansion coefficient of Shirisai de formed by reaction of the metal and S i is, T a Shirisai de is ^{8. 9 X 1 0- 6 / °} C, T i Shirisai de is 1. 0 5 X 1 0 - ⁵ / ° C, W Shirisai de is ^{8. 4 X 1 0- 6 / °} C, the C 0 Shirisai de 9. a 4 X 1 0 one ⁶ / ° C.

When one of the first layer and the second layer is processed by dry etching together with a layer containing at least one kind of metal sandwiched between them, and then the other is processed by dry etching, At the time of dry etching, the back surface of the layer that has been dry-etched first is exposed, and if dry etching is performed as it is, damage may occur. Therefore, to prevent this, preferably, the first layer and the second layer are preferably used. An etching stopper is provided between at least one of the layers and the layer containing one or more metals. An insulating film (such as a Si ₂ film or a Si 3 N ₄ film) is typically used as the etching stopper layer.

The first layer and the second layer may be the substrate itself, films formed by various film forming techniques, or thin layers of the substrate. The thickness of at least one of the first layer and the first layer is typically less than 100, more typically less than 50 um, more typically 10 m or less.

The above holds true for the following inventions as long as they do not contradict their properties.

The method for manufacturing a multilayer structure according to the second invention of the present invention includes:

A step of bonding a first layer and a second layer at least one of which is made of a single crystal material at room temperature via a layer containing at least one kind of metal.

The method for producing a multilayer structure according to the third invention of the present invention comprises:

Providing a first substrate and a second substrate, at least one of which is made of a single crystal material, forming a layer containing one or more metals on a main surface of the first substrate;

Bonding the second substrate and a layer containing one or more metals at room temperature.

Here, the first substrate and the second substrate correspond to the first layer and the second layer in the first invention, and the first substrate is made thinner, and the first substrate is formed by a film forming technique. Alternatively, the first substrate itself or the like is the first layer, and the second substrate is a thin layer, a film formed by a film forming technique, or the second substrate itself is the first layer.

The room-temperature bonding between the second substrate and the layer containing one or more metals is typically performed by bonding the main surface of the second substrate and the surface of the layer containing one or more metals in an ultra-high vacuum. The cleaning is performed, and pressure is applied in a state where they are opposed to each other.

After performing the room temperature bonding, if necessary, one of the first substrate and the second substrate is thinned by, for example, polishing the back surface. When the substrate to be thinned is made of a single crystal material, the thinned substrate becomes a single crystal layer. Further, the first substrate and the second substrate may be made of a single crystal material. A porous layer is formed on one of the main surfaces, a single crystal layer is epitaxially grown on the porous layer, and the second substrate and a layer containing at least one metal are bonded at room temperature. Separation may be performed at the position of the porous layer. This separation utilizes the fact that the porous layer becomes a mechanical weak point. The single crystal layer that is epitaxially grown on the porous layer is porous. It may be made of the same material as the substrate on which the layer is formed, but in some cases, may be made of a material different from the substrate on which the porous layer is formed. Further, a hydrogen accumulation layer is formed by ion-implanting hydrogen ions into one of the main surfaces of the first substrate and the second substrate made of a single crystal material, and the second substrate and one or more kinds of metals are formed. After bonding at room temperature to a layer containing, separation may be performed at the position of the hydrogen storage layer. This separation utilizes the fact that the hydrogen storage layer becomes a mechanical weak point.

If necessary, after forming a layer containing at least one type of metal on the main surface of the first substrate, and before performing room-temperature bonding with the second substrate, a layer containing at least one type of metal. Is patterned into a predetermined shape.

The functional structure according to the fourth invention of the present invention is:

A first layer and a first layer, at least one of which is made of a single crystal material, are joined at room temperature through a layer containing one or more metals;

At least one of the layer containing one or more metals, the first layer, and the second layer is patterned in a predetermined shape.

Typically, the layer containing one or more types of metal, the first layer, and the second layer are each patterned into a predetermined shape. These patterning shapes depend on the purpose of use of the functional structure and the functions it has. It is appropriately selected depending on the situation.

The functional structure is a structure having some function, and is generally, for example, a mechanical, electrical, electro-mechanical, optical, or electro-optical component or element. A specific example is a micro mirror used for scanning a laser beam in an optical disk device or the like.

The above holds true for the following fifth invention as long as it does not contradict its nature.

The method for manufacturing a functional structure according to the fifth aspect of the present invention includes:

Bonding the second substrate and a layer containing one or more metals at room temperature; and forming at least one of the layer containing one or more metals, the first substrate and the second substrate into a predetermined shape. And a patterning step.

Typically, before performing room-temperature bonding between the second substrate and the layer containing one or more types of metal, the layer containing one or more types of metal is patterned into a predetermined shape. Also, typically, after performing room-temperature bonding between the second substrate and a layer containing one or more types of metals, one of the first substrate and the second substrate is patterned into a predetermined shape. If necessary, one etching stopper is formed between at least one of the first substrate and the second substrate and a layer containing one or more types of metals.

The electron beam exposure mask according to the sixth invention of the present invention,

A first layer and a second layer, at least one of which is made of a single crystal material, are joined at room temperature via a layer containing one or more metals,

A layer containing at least one metal and at least a first layer and a second layer A mask pattern is formed on one side. As a material for forming a mask pattern, a material having at least one kind of metal and at least one of the first layer and the second layer is preferably used because it has a high ability to block an electron beam. It will be selected accordingly. The mask pattern is typically formed by a layer containing one or more metals and one of the first layer and the second layer, and the other of the first layer and the second layer forms the mask pattern. Is completely removed.

The above holds true for the following seventh invention.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a mask for electron beam exposure, comprising: preparing a first substrate and a second substrate, at least one of which is made of a single crystal material, Forming a layer containing the above metal;

Bonding the second substrate and the layer containing one or more metals at room temperature,

A step of forming a mask pattern by pattern-junging at least one of a layer containing one or more metals and at least one of the first layer and the second layer.

According to the present invention configured as described above, at least one of the first layer and the first layer made of a single-crystal material is interposed via a layer containing at least one kind of metal, for example, a layer made of a metal or an alloy. The first layer and the second layer or one of the first and second substrates by dry etching by bonding the first layer and the first substrate and the second substrate at room temperature. In this case, even if the etching is completed and the underlying layer containing one or more metals is exposed, the layer containing one or more metals has a sufficiently high electrical conductivity as compared to the SiO ₂ film, so that the charge No charge-up occurs, and the orbit of the ion is bent by the charge-up so that it is below the layer to be etched. It is possible to prevent the occurrence of the notching phenomenon in which the portion is hollowed out. For this reason, it is not necessary to switch the recipe of the etching process or install a mechanism for preventing charge up in the etching apparatus, so that the process is easy and the cost of the countermeasure can be reduced. Further, by forming a layer containing one or more kinds of metals and then patterning this layer into a predetermined shape, electrical wiring can be easily formed. Furthermore, by bonding the first layer and the second layer or the first substrate and the second substrate at room temperature, the thermal expansion differs from the conventional case where the substrates are bonded by using a high-temperature heat treatment. Can be eliminated. In other words, when bonding substrates using a heat treatment at a high temperature, if the substrates to be bonded have different coefficients of thermal expansion (linear expansion coefficients), the substrates are greatly warped during the heat treatment, and a flat bonded substrate is obtained. This makes it difficult to manufacture the functional structure. In order to prevent this, the materials of the substrates to be bonded must be the same, and the degree of freedom in selecting the substrates is significantly reduced. On the other hand, in the present invention, since the first layer and the second layer or the first substrate and the second substrate are bonded at room temperature, this problem is solved because there is no influence of the coefficient of thermal expansion, and High degree of freedom in selection. Therefore, for example, one of the first layer and the second layer or one of the first substrate and the second substrate can be formed of an insulator such as A1N. In the case of room temperature bonding, a reaction layer is not formed at the interface between layers or the interface between substrates. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view showing a multilayer structure according to a first embodiment of the present invention. FIGS. 2A and 2B are multilayer structures for manufacturing a micromirror mirror according to a second embodiment of the present invention. Plan view and cross section showing body, Fig. 3 A FIG. 3B is a plan view and a sectional view showing a micromirror according to a second embodiment of the present invention. FIGS. 4A to 4F are diagrams of a multilayer structure according to a third embodiment of the present invention. FIG. 5A to FIG. 5D are cross-sectional views for explaining a method of manufacturing a mask for electron beam exposure according to the fourth embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a multilayer structure according to a first embodiment of the present invention.

As shown in FIG. 1, in this multilayer structure, the (100) single-crystal Si layers 2 and 3 are joined at room temperature with the upper and lower sides of the metal film 1 interposed therebetween to form a three-layer structure. As the material of the metal film 1, for example, A1 or Cu can be used. In this case, the thickness of the (100) single crystal Si layer 2 depends on the use thereof, but is generally 100 Lim or less, typically 50 m or less. On the other hand, the (100) single-crystal Si layer 3 serves as a support of the multilayer structure, and is composed of the (100) single-crystal Si substrate itself, and has a thickness of, for example, 300 m to 1 m. mm.

The method for manufacturing this multilayer structure is as follows. First, a metal film 1 is formed on a (100) single-crystal Si layer 3 made of a (100) single-crystal Si substrate by a sputtering method or a vacuum evaporation method. The (100) single-crystal Si layer 3 on which the substrate was formed was opposed to another (100) single-crystal Si substrate at an interval in one ultra-high vacuum chamber, and A r After cleaning by irradiation with ions, normal pressure bonding is performed by applying pressure while keeping them in close contact. Thereafter, the (100) single-crystal Si substrate on the other side of the (100) single-crystal Si layer 3 is thinned to a predetermined thickness by polishing the back surface, and the (100) single-crystal Si substrate is thinned. i-layer 1. From the above, Fig. 1 shows A multilayer structure is manufactured.

According to the first embodiment, the following various advantages can be obtained. First, since the (100) single-crystal Si layer 2 has excellent workability by dry etching and is most suitable as a structural material, the (100) single-crystal Si layer 2 is desirably etched by dry etching. By processing into a shape, parts and elements having various functions can be manufactured. In this case, since the base of the (100) single-crystal Si layer 2 is a metal film 1 having excellent dry etching resistance, the (100) single-crystal Si layer 2 is, for example, RIE. When dry etching is performed by the method, the metal film 1 becomes one layer of etching. That is, since the etching characteristics of the (100) single crystal Si layer 2 and the metal film 1 are greatly different, the selection ratio at the time of etching can be made large, and the metal film 1 is made of the (100) single crystal single crystal. It works effectively as an etching stopper layer of the Si layer 2. It not only by an electrically conductive metal layer 1, the abnormality of the S 0 I substrate single crystal S i layer of the single crystal S i layer due to charge-up of S i 〇 ₂ film has become a problem when the dry etching ing of It is possible to suppress the occurrence of the etching phenomenon, that is, the notching phenomenon, and there is no problem that the lower portion of the (100) single-crystal Si layer 2 is cut off. In addition, it is not necessary to switch the recipe of the etching process or install a mechanism for preventing charging up in the etching device in order to suppress the occurrence of the notching phenomenon, so the process is simple. Low cost. Further, after the (100) single crystal Si layer 2 is processed, the metal film 1 can be expected to function as a current path / heat conduction path. Further, since room-temperature bonding is used for bonding the substrates, there is no risk of warpage of the substrate due to a difference in the thermal expansion coefficient between the metal used for the metal film 1 and Si, and there is no fear of a reaction between the metal and Si.

Next, a micro mirror according to a second embodiment of the present invention will be described. I will tell.

FIGS. 2A and 2B show a multilayer structure having a three-layer structure used for manufacturing the micromirror. FIG. 2A is a plan view, and FIG. 2B is an X-X line of FIG. 2A. It is sectional drawing along.

As shown in FIGS. 2A and 2B, this multilayer structure is formed by bonding (100) single-crystal Si layers 12 and 13 at room temperature with the upper and lower sides of metal film 11 interposed therebetween. The formation of the three-layer structure is the same as that of the first embodiment, except that the metal film 11 is patterned in a predetermined shape corresponding to the structure of the microphone opening mirror. In FIG. 2A, illustration of the (100) single crystal Si layer 12 is omitted.

The method for manufacturing the multilayer structure is the same as the method for manufacturing the multilayer structure according to the first embodiment, except that the metal film 11 is patterned into a predetermined shape after the metal film 11 is formed. is there.

FIGS. 3A and 3B show micromirrors manufactured using the multilayer structure shown in FIGS. 2A and 2B, wherein FIG. 3A is a plan view and FIG. FIG. 3 is a cross-sectional view taken along the line Y-Y of FIG.

This micromirror is manufactured using the multilayer structure shown in FIGS. 3A and 3B as follows. That is, first, a mirror surface 14 made of a metal film and a pair of electrode pads 15 and 16 are formed at predetermined positions on the (100) single crystal Si layer 12. The mirror surface 14 and the electrode pads 15 and 16 are formed by forming a metal film on the entire surface of the (100) single crystal Si layer 12 and then using the metal film as a mask with a resist pattern or the like. It can be formed by a pattern jung method by etching or by a lift-off method. Next, while the surface of the (100) single-crystal Si layer 12 is masked by a resist pattern having a predetermined shape, the (100) single-crystal Si layer is dry-etched. After the resist pattern 12 was etched to an intermediate depth, the resist pattern was removed, and the surface of the (100) single crystal Si layer 12 was again masked with a resist pattern having a predetermined shape. By completely etching the (100) single-crystal Si layer 12 by dry etching, a rectangular mirror portion 17 and two V-shaped hinge portions that support the mirror portion 17 are formed. 18 and 19 are formed. Thereafter, after removing the resist pattern, the (100) single-crystal Si layer 13 is masked by a resist pattern having a predetermined shape, and the (100) single-crystal Si layer 13 is dry-etched. The Si through layer 13 is etched through. As a result, a micro mirror 20 composed of the mirror part 17 and the hinge parts 18 and 19 is formed. The micromirror 20 is a cantilever supported at the root of the hinge 18-19. Here, the entire hinge portions 18 and 19 and the predetermined portion on the hinge portions 18 and 19 side of the mirror portion 17 are formed by the (100) single crystal Si layer 12 and the metal film 11. It has a bimorph structure consisting of two layers. The mirror surface 14 is formed on the mirror part 17, and the electrode surface. Heads 15 and 16 are formed at the roots of hinges 18 and 19, respectively.

In the micromirror 20 manufactured in this manner, the hinge portions 18 and 19 that generate heat by applying a pulse voltage between the electrode pads 15 and 16 have a coefficient of thermal expansion between S i and metal. It is deformed from the difference, and as a result it can move up and down. The micromirror 20 can be used, for example, as a device for scanning one laser beam in an optical disk device. In FIGS. 2A, 2B, 3A, and 3B, the fine pattern of the metal film 11 not used in the configuration of the micromirror 20 may be replaced by, for example, an electric It can be used as a standard wiring. As described above, according to the second embodiment, the microphone opening mirror can be easily manufactured using the multilayer structure shown in FIGS. 2A and 2B. That is, conventionally, a thin-film device having a fine metal pattern on the back side like the micromirror 120 could not be easily manufactured. In particular, it was difficult to manufacture a thin film device using a single crystal thin film such as the micromirror 120. On the other hand, in the second embodiment, a multi-layered structure in which a metal film 11 previously patterned into a predetermined shape is formed between (100) single-crystal Si layers 12 and 13 is formed. Since the micromirror 20 is manufactured using the body, a fine metal pattern can be formed on the back side of the micromirror 20, which is a thin film device using single crystal Si. It goes without saying that various advantages similar to those of the first embodiment can be obtained. Next, a method for manufacturing a multilayer structure according to the third embodiment of the present invention will be described. This manufacturing method is shown in FIGS. 4A to 4F.

In the third embodiment, as shown in FIG. 4A, a (100) single crystal Si substrate 21 is prepared, and the surface is cleaned by cleaning.

Next, as shown in FIG. 4B, after forming a porous Si layer 22 on the (100) single-crystal Si substrate 21 by anodization, the (100) The single-crystal Si layer 23 is epitaxially grown to form a structure having the (100) single-crystal Si layer 23 on the porous Si layer 22.

Next, as shown in FIG. 4C, a metal film 24 is formed on the (100) single crystal Si layer 23 by a sputtering method.

Next, as shown in FIG. 4D, a (100) single crystal Si substrate 25 whose surface has been cleaned by cleaning in advance is separately prepared, and the (100) single crystal Si substrate 25 is prepared in an ultra-high vacuum. After cleaning the surface of the single crystal Si substrate 25 and the surface of the metal film 24 on the single crystal Si (100) substrate 21 by Ar ion irradiation, Thus _c to the room temperature bonding by brought into close contact with their surfaces on each by applying pressure, (1 0 0) single crystal S i substrate 2 1 (1 0 0) firmly bonded to the single crystal S i board 2 5 Then, it becomes one substrate.

Next, as shown in FIG. 4E, a water jet is injected toward the porous Si layer 22 of the (100) single-crystal Si substrate 21 to form a porous Si layer. Separate at 1 and 2.

Next, the porous Si layer 22 remaining on the outermost surface of one of the separated (100) single crystal Si substrates 25 is chemically removed. In this way, as shown in FIG. 4F, the metal film 24 and the (100) single-crystal Si layer 27 are sequentially formed on the (100) single-crystal Si substrate 25. A multi-layer structure having a three-layer structure is manufactured.

According to the third embodiment, since the (100) single crystal Si layer 23 is formed by epitaxial growth, its thickness is easily reduced to about 1 / m or less. Not only can it be controlled, but the in-plane distribution of its thickness can be controlled with high precision. In addition, advantages similar to those of the first embodiment can be obtained.

Next, a method for manufacturing an electron beam exposure mask according to a fourth embodiment of the present invention will be described. This manufacturing method is shown in FIGS. 5A to 5D.

In the fourth embodiment, first, as shown in FIG. 5A, a (100) single crystal Si substrate 31 is formed on a (100) single-crystal Si substrate 31 by using, for example, a normal temperature bonding method as in the third embodiment. Then, a multilayer structure having a three-layer structure in which a metal film 32 and a (100) single-crystal Si layer 33 are sequentially formed is manufactured.

Next, as shown in FIG. 5B, the surface of the (100) single-crystal Si layer 33 is formed by a resist pattern (not shown) made of an electron beam resist having a predetermined shape corresponding to the mask pattern. The (100) single-crystal Si layer 3 is dry-etched until the metal film 32 is exposed in a state masked by You. Next, the metal film 32 is dry-etched again using this resist pattern. Thus, a line-and-space mask pattern 34 having a two-layer structure of the metal film 32 and the (100) single-crystal Si layer 33 is formed.

Next, as shown in FIG. 5C, a resist pattern having a predetermined shape with an opening corresponding to the mask pattern 34 is formed on the back surface of the (100) single crystal Si substrate 31, Using this resist pattern as a mask, through-holes are formed by dry-etching the (100) single-crystal Si substrate 31 from the back side. As a result, the mask pattern 34 has a structure floating in the air except for its end.

As described above, the intended electron beam exposure mask is manufactured.

According to the fourth embodiment, since the mask pattern 34 of the mask for electron beam exposure has a two-layer structure of the metal film 32 and the (100) single-crystal Si layer 33, When exposing a semiconductor wafer or the like using an electron beam exposure mask, heat generated by the electron beam exposure mask heated by the electron beam irradiation is transferred to a metal film 3 having particularly good thermal conductivity through a heat conduction path. As a result, deformation of the mask pattern 34 due to a rise in temperature can be effectively prevented. Therefore, it is possible to perform exposure that faithfully reflects the shape of the mask pattern 34.

Hereinafter, specific embodiments of the present invention will be described.

Example 1 Example corresponding to the first embodiment

In the multilayer structure shown in FIG. 1, the (100) single-crystal Si layer 3 has a diameter of 5 inches and a thickness of 500 m (100) single-crystal Si substrate; 0) The thickness of the single crystal Si layer 1 is 0 m. As the metal film 1, an A1 film having a thickness of 1 μm was used. These layers are firmly bonded to each other and can be used without any problem even when heated to about 400 ° C. This multilayer structure was manufactured by the cold bonding method as follows. First, an A1 film having a thickness of 1 is formed by a sputtering method on a (100) single crystal Si substrate 3 having a diameter of 5 inches and a thickness of 500 m serving as a supporting substrate. On the other hand, also a diameter of a thickness of 5 Inchi 2 0 0 (1 0 0) zm is prepared separately monocrystal S i substrate, both 1 X 1 0- ⁹ T 0 rr total one scan pressure board The substrates were held opposite to each other in an ultra-high vacuum vessel and irradiated with an Ar ion beam at a pressure of 1 × 10 ⁻³ τ 0 rr to clean the surfaces of the substrates. At this time, the accelerating voltage of the Ar ion was 1 kV.

Next, pressure was applied by bringing both substrates into close contact at room temperature. The applied pressure was 1 MPa. As a result, a (100) single-crystal Si substrate 3 having a thickness of 500 m and an A1 film as the metal film 1 on the surface 3 and a (100) single crystal Si having a thickness of 200 m The substrate was bonded at room temperature. Subsequently, the (100) single crystal Si substrate having a thickness of 200 m was polished from the back surface side, and the thickness of the Si layer remaining on the A 1 film as the metal film 1 was 2 mm. The thickness was reduced to 0 m to form a (100) single crystal Si layer 2. As a result, the intended multilayer structure was manufactured.

The multilayer structure manufactured in this manner can suppress the notching phenomenon during the dry etching of the (100) single-crystal Si layer 2 and contribute to the realization of an excellent etched shape.

Example 1 Example corresponding to the second embodiment

A (100) single crystal Si substrate having a diameter of 5 inches was used as the (100) single crystal Si layer 13 of the multilayer structure shown in FIGS. 2A and 2B. The thickness of the (100) single crystal Si layer 13 is 525 m, and the thickness of the upper (100) single crystal Si layer 12 is 20 m. The metal film 11 is an A1 film having a thickness of 1. This multilayer structure can be manufactured by the same process as in Example 1. However, after forming an A 1 film as a metal film 11 on a (100) single crystal Si layer 13, This is different from Example 1 in that normal temperature bonding is performed after pattern jungling of one film.

Using this multilayer structure, a micromirror shown in FIGS. 3A and 3B was manufactured. The mirror surface 14 and the electrode pads 15 and 16 are formed by forming a Cr / Au film on the (100) single-crystal Si layer 12 by the sputtering method, and then pattern-jewing the Cr / Au film. Thus, they were simultaneously formed. Next, the basic structure of the micromirror 20 was formed by dry-etching the (100) single-crystal Si layer 12. The (100) single crystal Si layer 12 was a low resistance layer having a specific resistance of 0.01 × cm.

Next, dry etching was performed from the back side of the (100) single-crystal Si layer 13, and the micromirror 20 was used as a support substrate as shown in FIG. 3B. It is possible to move freely from the Si layer 13. The hinge sections 18 and 19 of the microphone opening mirror 20 have a (100) single-crystal Si layer 12 and an A1 film formed in advance as a metal layer 11 on the lower side, and a bimorph It has a structure.

When dry-etching the (100) single-crystal Si layer 13 from the back side, the upper etching is performed by the over-etching after the (100) single-crystal Si layer 13 penetrates. Since there is a concern that the (100) single crystal Si layer 12 may be damaged, for example, when manufacturing a multilayer structure, the (100) single crystal Si layer _By forming one insulating film such as _two films and then forming the metal film 11 thereon, this insulating film becomes one layer of etching (100) single crystal Si Damage to the layer 12 can be effectively prevented. This insulating film also reduces the value of the current flowing when current flows through the hinge portions 18 and 19 of the bimorph structure. It also works to reduce power consumption.

Example 3 Example corresponding to the third embodiment.

The multilayer structure was manufactured according to the manufacturing method shown in FIGS. 4A to 4F. First, (100) single crystal Si substrates 21 and 25 having a diameter of 5 inches are prepared. The thickness of the (100) single crystal Si substrate 21 was 525 m, and the thickness of the (100) single crystal Si substrate 25 was 200 m. Next, the (100) single crystal Si substrates 21 and 25 are anodized to form a porous Si layer 22 having a thickness of 0.8 m. On (22), a (100) single crystal Si layer (23) was grown by an epitaxial thickness of 0.6. As a result, a structure in which the (100) single crystal Si layer 23 was formed on the porous Si layer 22 was produced.

Next, an Al film having a thickness of 1 / m was formed as a metal film 22 on the (100) single crystal Si layer I3 by a sputtering method. Subsequently, the (100) single-crystal Si substrate 21 and the (100) single-crystal Si substrate 25 formed up to the metal film 22 were put into an ultra-high vacuum chamber, and their surfaces were cleaned. After cleaning by cleaning by Ar ion beam irradiation, they were brought into close contact with each other and pressure was applied to perform normal temperature bonding. The joining conditions were the same as in Example 1. As a result, a composite substrate was obtained in which the (100) single-crystal Si substrate 21 and the (100) single-crystal Si substrate 25 formed up to the metal film 22 were integrated.

Next, a water jet was sprayed on the porous Si layer 22 of the composite substrate to separate the composite substrate into two. It was then removed by treating the porous S i layer 2 2 of one (1 0 0) single crystal S i outermost surface of the substrate 2 5 in a mixed solution of HF and H ₂ 0 _2. The multilayer structure manufactured in this way has a better in-plane thickness than a multilayer structure manufactured by a manufacturing method in which one substrate is thinned by polishing the back surface after bonding the substrates. It has uniformity and is suitable for forming a single-crystal Si layer with a thickness of about 1 m.

Example 4 Example corresponding to the fourth embodiment.

In the multilayer structure shown in FIG. 5A, the thickness of the (100) single crystal Si substrate 31 is 5255 wm, and the thickness of the (100) single crystal Si layer 33 is 0. 6 um. As the metal film 32, an A1 film having a thickness of 0.1 m was used. Using this multilayer structure, a mask for electron beam exposure was manufactured as follows. First, an electron beam resist is applied on the (100) single crystal Si layer 33, and the electron beam resist is exposed to a desired pattern shape by an electron beam drawing method, and then the resist is developed. A resist pattern is formed. Next, the (100) single-crystal Si layer 33 is pattern-junged by performing dry etching using this resist pattern to obtain a desired pattern shape. Subsequently, the lower metal film 32 is also dry-etched using this resist pattern to form a pattern having the same shape as the pattern shape of the (100) single-crystal Si layer 33. Thus, a mask pattern 34 is formed.

Next, dry etching was performed from the back side of the (100) single crystal Si layer 31 to form an opening immediately below the mask pattern 34, thereby forming a structure in which the mask pattern 34 was suspended in the air.

In the mask for electron beam exposure manufactured in this manner, the (100) single-crystal Si layer 33 constituting the mask pattern 34 is a tough material having almost no residual stress. The lower metal film 32 has an excellent drawing capability because it has a function of quickly releasing the charge charged up to the electron beam exposure mask and the heat generated by the electron beam irradiation at the time of exposure.

Although the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments and examples. Various modifications based on the technical concept of the present invention are possible.

For example, the numerical values (dimensions such as thickness and diameter), materials, structures, shapes, plane orientations, processes, and the like mentioned in the above-described embodiments and examples are merely examples, and numerical values different from these may be used as necessary. A material, a structure, a shape, a plane orientation, a process, or the like may be used.

Specifically, in the first embodiment, for example, a ceramic material may be used instead of the (100) single crystal Si layer 3. It is also very useful to use a multilayer structure having a metal film between a ceramic substrate and a single-crystal Si substrate instead of the multilayer structure of the first embodiment. Further, a structure such as a cavity may be provided in advance on the side to be a supporting substrate, and a substrate having a metal film may be bonded thereto to manufacture a similar structure.

Further, in Embodiment 3 and Example 3, the porous Si layer 22 was used as the separation layer, but the porous Si layer 22 was formed on the (100) single crystal Si substrate 21. Instead, hydrogen ions may be implanted into the (100) single crystal Si substrate 21 and a hydrogen storage layer formed thereby may be used as a separation layer.

Further, in Embodiment 4 and Example 4, a layer made of, for example, SiC or diamond may be used instead of the (100) single crystal Si layer 33.

As described above, according to the present invention, a first layer and a second layer at least one of which is made of a single crystal material via a layer containing at least one kind of metal, for example, a layer made of a metal or an alloy Alternatively, by bonding the first substrate and the second substrate at room temperature, various functional structures such as a micromirror and an electron beam exposure mask can be manufactured inexpensively, simply, and accurately.

Claims

The scope of the claims

1. A multilayer structure wherein at least one of a first layer and a second layer made of a single crystal material is bonded at room temperature via a layer containing one or more kinds of metals.

2. The multilayer structure according to claim 1, wherein the first layer and the second layer are made of a single crystal material.

3. The multilayer structure according to claim 1, wherein the first layer and the second layer are made of the same material.

4. The multilayer structure according to claim 1, wherein the first layer and the second layer are made of different materials.

5. One of the first layer and the second layer is composed of Si, S in Ge; (where 0 <x≤1), Si C, C or III-V compound semiconductor. 2. The multilayer structure according to claim 1, wherein the other is made of Si, glass or ceramic.

6. The multilayer structure according to claim 1, wherein at least one of the first layer and the first layer is made of single crystal Si.

7. The multilayer structure according to claim 1, wherein the first layer and the second layer are made of single crystal Si.

8. The multilayered ferrite body according to claim 1, wherein at least one of the first layer and the second layer is made of a material that can be dry-etched.

9. The multilayer structure according to claim 1, wherein the layer containing at least one metal is made of a metal or an alloy.

10. The multilayer structure according to claim 1, wherein the layer containing at least one metal is patterned in a predetermined shape. 1 1. 2. The multilayer according to claim 1, wherein an etching stopper layer is provided between at least one of the first layer and the second layer and a layer containing at least one kind of metal. Structure.

1 2. The multilayer structure according to claim 11, wherein the etching stopper layer is an insulating film.

1 3. The first layer and the second least also one of the layer thickness is 1 0 0 multilayered structure according to claim 1, wherein, characterized in that m is less than body _t 1 4. 1 or more A method for producing a multilayered structure, comprising a step of bonding a first layer and a second layer, at least one of which is made of a single crystal material, at room temperature via a layer containing a metal.

15. A step of preparing a first substrate and a second substrate, at least one of which is made of a single crystal material, and forming a layer containing one or more metals on a main surface of the first substrate;

Bonding the second substrate and the layer containing one or more types of metal at room temperature.

16. The main surface of the second substrate and the surface of the layer containing one or more types of metals are subjected to cleaning treatment in an ultra-high vacuum, and pressure is applied in a state where the surfaces are opposed to each other. 16. The method for producing a multilayer structure according to claim 15, wherein the substrate and the layer containing one or more kinds of metals are bonded at room temperature.

17. The method for manufacturing a multilayer structure according to claim 15, wherein after performing the room-temperature bonding, one of the first substrate and the second substrate is thinned.

18. A porous layer is formed on one main surface of the first substrate and the second substrate made of a single crystal material, and the single crystal layer is epitaxially grown on the porous layer. Including the second substrate and the one or more metals 16. The method for producing a multilayer structure according to claim 15, wherein, after bonding to the porous layer at room temperature, separation is performed at the position of the porous layer.

1 9. A hydrogen storage layer is formed by injecting hydrogen ions into one main surface of the single-crystal material of the first substrate and the second substrate, and the second substrate and the second substrate The method for producing a multilayered structure according to claim 15, wherein after bonding at room temperature to a layer containing one or more kinds of metals, separation is performed at the position of the hydrogen storage layer.

20. After forming the layer containing one or more types of metal, patterning the layer containing one or more types of metal into a predetermined shape before performing the room temperature bonding. The method for producing the multilayer structure according to the range 15, wherein

21.1. A first layer and a second layer, at least one of which is made of a single crystal material, are joined at room temperature via a layer containing at least one metal,

A functional structure, characterized in that at least one of the layer containing at least one kind of metal, the first layer and the second layer is patterned in a predetermined shape.

22. The functional structure according to claim 21, wherein the layer containing at least one metal, the first layer, and the second layer are each patterned into a predetermined shape. .

23. The functional structure according to claim 21, wherein the functional structure is a micromirror.

24. a step of preparing a first substrate and a second substrate, at least one of which is made of a single crystal material, and forming a layer containing one or more metals on a main surface of the first substrate;

Bonding the second substrate and the layer containing one or more metals at room temperature, Patterning at least one of the layer containing at least one kind of metal, the first substrate and the second substrate into a predetermined shape, and manufacturing the functional structure. Method.

25. The method for producing a functional structure according to claim 24, wherein the layer containing the one or more kinds of metals is patterned in a predetermined shape before performing the room-temperature bonding.

26. The method for manufacturing a functional structure according to claim 24, wherein after performing the room temperature bonding, one of the first substrate and the second substrate is patterned into a predetermined shape. .

27. An etching stopper layer is formed between at least one of the first substrate and the second substrate and the layer containing one or more metals. A method for manufacturing the functional structure according to the above. 28. At least one of the first layer and the second layer, each of which is made of a single-crystal material, is joined at room temperature through a layer containing one or more metals,

An electron beam exposure mask, characterized in that a mask pattern is formed by a layer containing one or more types of metals and at least one of the first layer and the second layer.

29. A step of preparing a first substrate and a second substrate, at least one of which is made of a single crystal material, and forming a layer containing one or more metals on a main surface of the first substrate;

Forming a mask pattern by pattern-junging the layer containing at least one kind of metal and at least one of the first layer and the second layer. The method of manufacturing the mask.