JPH095985A - Transfer mask - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a transfer mask having a long durability time and practical durability. A transfer mask in which an opening 11 is formed in a thin film portion 13 supported by a support frame portion 12, wherein a conductive layer 3 is formed on the surface of the transfer mask. And the diffusion prevention layer 2 is provided between them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer mask used for electron beam exposure, ion beam exposure, X-ray exposure and the like.

[0002]

2. Description of the Related Art At present, electron beam lithography, ion beam lithography, X-ray lithography, etc. are attracting attention as a technology for manufacturing next-generation sub-half-micron or quarter-micron ultrafine elements and the like. It is still unclear whether it will become the mainstream of mass production technology.

Among them, the electron beam exposure using an electron beam is conventionally called a direct writing method (so-called one-stroke writing method) in which an exposure pattern is scanned with an electron beam (a thin beam spot) to perform drawing. Although the method has been put to practical use, this method can draw an ultrafine pattern, but it is not suitable for mass-production LSI such as memory because the exposure time is extremely long and the throughput is low. It was considered that it could not play a leading role in LSI mass production technology.

However, in recent years, various elemental patterns repeatedly appearing in an exposure pattern can be partially exposed by a transfer method using a mask, and a desired combination is obtained by combining these various elemental pattern transfer. A drawing method called partial batch exposure (sometimes referred to as block exposure or cell projection exposure) has been proposed that enables rapid pattern exposure, and it enables short drawing time and mass production, and enables the drawing of ultrafine patterns. Therefore, it is rapidly emerging as the next-generation LSI technology and is in the spotlight.

[0005] The mask used in this method is usually one in which a number of different elemental patterns are formed on a single mask, and the exposure using this mask involves applying an electron beam in an elemental pattern (opening). After molding and partially exposing a predetermined section (block or cell) at a time, when the transfer of one elementary pattern is completed, the electron beam is deflected and / or the mask is moved, or both are performed. Then, the next elementary pattern is transferred, and this operation is repeated to perform drawing.

By the way, a charged particle beam exposure mask used for charged particle beam exposure such as partial batch exposure with an electron beam is generally a penetrating pattern that allows a charged particle beam to pass through a thin film portion supported by a support frame portion. A so-called perforated mask (stencil mask; Stenci) with (openings) formed
l mask). In other words, there is no material that transmits the charged particle beam well, and no material can be interposed in the portion that allows the charged particle beam to pass. Therefore, this portion must be penetrated. Also, if this through pattern is formed on a thick substrate or the like, the passing charged particle beam is affected by the side wall of the through pattern and accurate transfer cannot be performed. Therefore, the part where the through pattern is formed (the part that blocks the charged particle beam is blocked). ) Must be a thin film. Also,
In order to support the thin film while maintaining planar accuracy, a support frame having a predetermined strength is required.

A transfer mask used for such partial batch exposure and the like has been conventionally manufactured by various methods.
From the viewpoint of workability and strength, it is common to manufacture a silicon substrate (such as a commercially available silicon wafer) by using a lithography technique or a micromachining technique. In particular,
For example, the back surface of the silicon substrate is etched to form a support frame portion and a thin film portion supported by the support frame portion, and a through hole is formed in the thin film portion to manufacture a transfer mask.

In such a transfer mask made of a simple substance of silicon, the silicon thin film portion in which the opening is formed is beam-etched by the electron beam or heated by the electron beam irradiation as it is, and thus the durability against the electron beam is poor. . Therefore, a conductive layer of gold (Au), tungsten (W), platinum (Pt), or the like is usually formed on the silicon thin film portion to improve the durability of the mask during electron beam irradiation. Further, since these metals are good conductors and are excellent in electron conductivity and thermal conductivity, they contribute to the prevention of beam shift due to charging (charge-up) and the thermal distortion prevention effect of the mask due to heat generation. Furthermore, since these metals have excellent shielding properties against electron beams and act as electron beam (energy) absorbers, the silicon thin film portion can be made thin, and therefore, the precision of the aperture can be improved and the electron generated by the side wall of the aperture can be improved. The influence on the line can be reduced.

[0009]

However, the transfer mask having a conductive layer formed on the silicon thin film portion has the following problems.

That is, at the practical level in which mass productivity and cost are taken into consideration, the transfer mask is required to have a service life of 1000 hours. A heavy metal is usually used as the conductive layer, and the film thickness thereof is limited to about 2 μm from the viewpoint of not reducing the dimensional accuracy of the opening pattern. Further, considering the film stress, the limit of the formed film thickness is about 1 μm.

Table 1 shows a heavy metal layer (density of 19.3 g) for electron beams with acceleration voltages of 50 keV and 100 keV.
/ Cc of gold) and the penetration distance (range) of electrons into silicon.

[0012]

[Table 1]

As shown in Table 1, generally, both the heavy metal layer of Au or the like and the silicon thin film portion prevent the transmission of electrons. Therefore, unless the heavy metal layer alone can completely absorb the electrons, the electrons will penetrate into the silicon.

When electrons penetrate into silicon, electron energy activates silicon atoms, causing a diffusion reaction with the heavy metal layer. Such a diffusion reaction progresses with the passage of electron beam irradiation time, and due to this diffusion reaction, the thermal and electrical characteristics originally possessed by the heavy metal layer,
There is a problem in that the film density is reduced, and eventually the necessary and sufficient durability characteristics are impaired, and the practical durability (about 1000 hours) in use durability cannot be achieved.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a transfer mask which has a long durability time and has a practical durability.

[0016]

In order to achieve the above object, a transfer mask of the present invention is a transfer mask in which an opening is formed in a thin film portion supported by a support frame portion, and the transfer mask is formed on the surface of the transfer mask. In a transfer mask having a conductive layer formed, a diffusion prevention layer is provided between the surface of the transfer mask and the conductive layer.

In the transfer mask of the present invention, in the transfer mask of the present invention, the diffusion prevention layer is made of a conductive material, and the conductive material constituting the diffusion prevention layer is W, Zr, Ta. , A metal carbide of any metal selected from Mo, Ti, and Nb, or Zr, Ta, and M
o, Ti, Nb, a metal nitride of any metal, the conductive material forming the diffusion preventing layer is carbon, or the diffusion preventing layer is heat-treated to prevent diffusion. The structure is a dense film with high function.

Further, the transfer mask of the present invention is a transfer mask formed by forming an opening in a thin film portion supported by a support frame portion, wherein the transfer mask has a conductive layer formed on the surface of the transfer mask. A structure in which a buffer layer for stress relaxation between these layers is provided between the surface and the conductive layer, or
A buffer layer is provided between the diffusion prevention layer and the surface of the transfer mask and / or the conductive layer to relax the stress between these layers.

Hereinafter, the present invention will be described in detail.

The transfer mask of the present invention is shown in FIG.
As shown in (b) and (c), a transfer mask in which an opening 11 is formed in a thin film portion 13 supported by a support frame portion 12, the transfer mask having a conductive layer 3 formed on the surface of the transfer mask. In the above, the diffusion preventing layer (barrier layer) 2 is provided between the transfer mask surface and the conductive layer 3.

Here, as the material for forming the diffusion prevention layer,
There is no particular limitation as long as it is a material that can prevent the diffusion reaction between the transfer mask surface and the conductive layer, and various metals, alloys, metal oxides and the like can be used, but from the viewpoint of charge-up prevention, a conductive material is used. Preferably there is. Also, a thermally stable material is preferable.

The electron beam shielding property (absorber function) of the diffusion prevention layer is not an essential requirement, but a material having a high electron beam shielding property is preferable in order to reduce the required film thickness of the conductive layer.

As the material for forming the diffusion prevention layer, for example,
Metal carbides such as W, Zr, Ta, Mo, Ti, Nb,
Alternatively, metal nitrides such as Zr, Ta, Mo, Ti and Nb may be used. Since these materials have conductivity and are thermally stable, they sufficiently function as a diffusion preventing layer. Also, the adhesion property is sufficient.

Carbon can also be used as the diffusion preventing layer. Carbon itself easily transmits an electron beam, but it is electrically conductive, and silicon activated by electron energy reacts with carbon to form SiC at the silicon / carbon interface, thus forming SiC. However, since it can prevent the diffusion reaction from further proceeding, it sufficiently functions as a diffusion preventing layer.

The method for forming the diffusion prevention layer is not particularly limited, but examples thereof include sputtering method, room temperature sputtering method, vacuum vapor deposition method, ion beam vapor deposition method, CVD method, ion plating method, electrodeposition method and plating method. A thin film forming method may be used.

The thicker the diffusion preventing layer is, the higher the barrier effect (shielding effect) is, but about 50 to 100 nm is sufficient.

The diffusion prevention layer is preferably subjected to a heat treatment (annealing), if necessary, in order to improve the denseness of the film and improve the film quality as the barrier layer.

The conductive layer is preferably formed of a material that satisfies the required characteristics (density, electric resistance, thermal conductivity, linear expansion coefficient, etc.) in a well-balanced manner and has excellent material characteristics.

As such a material, iridium (I
r), tantalum (Ta), tungsten (W), molybdenum (Mo), gold (Au), platinum (Pt), silver (A)
g), Ru (ruthenium), Re (rhenium), Rh
(Rhodium), Pd (palladium), Nb (niobium), and other metals, alloys containing these metals, intermetallic compounds containing these metals (intermetallic compounds include boron, carbon, silicon, germanium, antimony, Including non-metals such as selenium and interstitial compounds), and metal compounds containing these metals and at least one element of oxygen, nitrogen, and carbon.

By adjusting the composition, the ratio, the physical properties, etc. of the conductive layer in this way, the material properties, adhesion, etc. of the conductive layer can be controlled.

The conductive layer is usually a single layer, but may be a laminated layer made of different materials. Examples of such a conductive layer include an iridium alloy layer / tungsten layer / iridium alloy layer, a tungsten layer / iridium alloy layer, and the like.

When the conductive layer is an alloy, the conductive layer may have an inclined structure in which the ratio of alloy components changes as the deposition proceeds from the substrate interface.

The method of forming the conductive layer is not particularly limited, but is, for example, a thin film such as a sputtering method, a room temperature sputtering method, a vacuum evaporation method, an ion beam evaporation method, a CVD method, an ion plating method, an electrodeposition method, a plating method. The forming method may be mentioned.

The conductive layer preferably has a thickness of about 0.2 to 2.0 μm. If the thickness of the conductive layer is less than 0.2 μm, the durability against electron beams becomes poor, and the thickness is 2.0 μm.
When it exceeds m, it becomes difficult to form a film, it becomes difficult to control the film stress, and it becomes difficult to perform a highly accurate dry etching process.

The conductive layer is formed not only on the surface of the transfer mask but also on the side surface and / or the back surface side of the transfer mask (including the tapered portion of the back surface of the substrate and the back surface side of the thin film portion) and the side wall of the opening. May be. As a result, heat dissipation characteristics and antistatic characteristics can be improved.

In the present invention, when the diffusion preventing layer has poor adhesion to the transfer mask surface (silicon) and the conductive layer, the diffusion preventing layer, the transfer mask surface and the transfer mask surface are formed for the purpose of improving the adhesion property. A buffer layer such as a metal layer may be formed between the conductive layer and / or the conductive layer.

In this case, it is preferable to select the material of the buffer layer in consideration of the lattice constant and the linear expansion coefficient of each layer to relieve the stress and secure the adhesive property.

Examples of the material for forming the buffer layer include metals such as Ti and W, silicide compounds such as Ti, Ta, W and Mo.

A buffer layer may be formed between the transfer mask surface and the conductive layer for the purpose of only relieving the stress between the transfer mask surface and the conductive layer. Further, by selecting the material for forming the buffer layer, it is possible to give the buffer layer a function as a diffusion preventing layer. in this case,
The buffer layer and the diffusion prevention layer are the same layer.

The method of forming the buffer layer is not particularly limited, but is, for example, a thin film such as a sputtering method, a room temperature sputtering method, a vacuum evaporation method, an ion beam evaporation method, a CVD method, an ion plating method, an electrodeposition method, a plating method. The forming method may be mentioned.

The thickness of the buffer layer cannot be generally stated because it is intended to adjust the stress balance, but it is usually 20 to 50.
The range is 0 nm.

The buffer layer, the diffusion preventing layer and the conductive layer may be formed by the same method or different methods. The method for forming these layers can be appropriately selected in consideration of film quality (film denseness, crystal structure, defect-free property, etc.) and cost.

A preferable combination of the buffer layer, the diffusion prevention layer and the conductive layer is, for example, Ti (buffer layer) / TiN (diffusion prevention layer) / Au (conductive layer).

Next, a method of manufacturing the transfer mask of the present invention will be described.

The transfer mask of the present invention is produced by processing a silicon substrate or the like by various conventionally known methods to prepare a transfer mask made of silicon or the like in which an opening is formed in a thin film portion supported by a support frame, and It can be obtained by sequentially forming a buffer layer (intervening if necessary), a diffusion preventing layer, a buffer layer (interposing as necessary), and a conductive layer on the surface of the transfer mask by a thin film forming method (first method). ).

In the transfer mask of the present invention, after a buffer layer (which is interposed if necessary), a diffusion prevention layer, a buffer layer (which is interposed as necessary), and a conductive layer are sequentially formed on the substrate before forming the openings. Alternatively, it is possible to form the layer and the substrate (the thin film portion or a portion to be the thin film portion) by forming the opening continuously and integrally (second method).

In the first method, the transfer mask formed by forming openings in the thin film portion supported by the support frame may be a transfer mask produced by various conventionally known methods. The material, composition, etc. are not particularly limited.

In general, the transfer mask is processed by dry etching the surface of the substrate with high accuracy to form an opening pattern, and the back surface of the substrate is wet-etched (wet etching) while leaving a supporting frame. ) To form a thin film portion. In this case, either the opening pattern processing or the back surface processing may be performed first.

Lithography is generally used to etch the front and back of the substrate into a predetermined pattern.
The etching mask layer is etched into a predetermined pattern, and the pattern of the etching mask layer is transferred to the substrate to process the front and back surfaces of the substrate.

In addition to the above method, a method of forming an opening (opening) pattern portion by electric discharge machining using a silicon substrate (Japanese Patent Laid-Open No. 217876/1993), or coating a photosensitive glass on the silicon substrate. A method of using the photosensitive glass as it is as a mask material to omit the resist process (JP-A-4-240719) or a method of using a boron layer as an etching stopper layer (JP-A-2-76216) is used. You can also

In the second method, as described above, a buffer layer (which is interposed if necessary), a diffusion prevention layer, and a conductive layer are sequentially formed on the substrate before the opening is formed, and then these layers and the substrate (the thin film portion or An opening is continuously and integrally formed in a portion to be a thin film portion).

When the opening is formed by continuously and integrally dry etching as described above, the opening including the buffer layer, the diffusion prevention layer and the conductive layer can be formed by continuous dry etching in one step and in a short time. In addition to this, it is possible to easily form a highly accurate opening.

When the openings are formed continuously and integrally, it is preferable that the buffer layer, the diffusion preventing layer and the conductive layer are formed of a dry-etchable material. Further, these layers are preferably formed of a material having a high chemical resistance to an acid and capable of removing an organic substance such as carbon attached as a contaminant in a vacuum apparatus by acid cleaning.

The other steps in the second method are the same as those in the first method.

As described above, in the first method and the second method, in general, the surface portion of the substrate is processed with high precision by dry etching to form the opening pattern, and
The back surface of the substrate is wet-etched (wet etching) leaving the support frame portion to form a thin film portion, and a transfer mask is manufactured.

Here, as the substrate material, Si, Mo,
Al, Au, Cu, etc. may be mentioned. However, from the viewpoint of chemical resistance, processing conditions, dimensional accuracy, etc., two silicon plates are made into Si.
SOI (Silicon on) with a structure that is bonded via an O ₂ layer
Insulator) substrate, oxygen ions are implanted into a silicon substrate at a high concentration to form an oxide film by heat treatment, SIMOX (se
It is preferable to use a paration by implanted oxygen) substrate, a silicon substrate, or the like. When a silicon substrate doped with phosphorus or boron is used, the electronic conductivity of the silicon substrate can be adjusted.

When an SOI substrate or a SIMOX substrate is used as the substrate, the front and back of the substrate can be processed by using the SiO ₂ layer as an etching stop layer (etching stopper layer), and the processing such as the formation of a thin film portion is easy. (JP-A-6-
130655, etc.).

The material and forming method of the etching mask layer are not particularly limited, and various conventionally known materials and forming methods can be used.

Specifically, as the dry etching mask layer used for forming the openings, etc., in addition to the SiO ₂ layer, SiC is used.
Layer, Si3N4 layer, sialon (composite mixture of Si and Al) layer, inorganic layer such as SiON layer, organic layer such as resist and photosensitive film, tungsten, zirconium,
Metals such as metals such as titanium, chromium and nickel, alloys containing these metals, and metal layers such as metal compounds of these metals or alloys with oxygen, nitrogen, carbon and the like can be used.

The dry etching mask layer can be formed by various thin film forming methods. For example, as a method for forming the SiO ₂ layer, a thin film forming method such as a method using a sputtering method, an evaporation method, a thermal oxidation method, a CVD method, a method using SOG (spin-on-glass), photosensitive glass, photosensitive SOG, or the like. Is mentioned.

The patterning of the dry etching mask layer is performed by using a lithographic technique, and is patterned into a desired shape. Specifically, for example, a resist is applied on the dry etching mask layer, a resist pattern is formed by exposure and development, and the dry etching mask layer is dry-etched using this resist pattern as a mask. Transfer to a layer. The resist process can be omitted when using photosensitive glass or photosensitive SOG as the dry etching mask layer. The resist is removed after the etching of the etching mask layer. As an etching gas for the dry etching mask layer (SiO ₂ layer, etc.), a fluorocarbon-based gas (SF ₆ / O ₂ , CF ₄ /
O ₂ , C ₂ F ₆ / O _{2 and the} like are used.

Next, using the patterned dry etching mask layer as a mask, the substrate surface is subjected to trench etching by a dry etching technique to a predetermined depth to form an opening in the thin film portion or a portion to be the thin film portion. .

The dry etching conditions are as follows.
Etching temperature, used gas, gas pressure, RF output and the like are mentioned, and it is preferable to adjust these conditions so that a vertical opening is formed.

The back surface of the substrate is processed by etching,
The thin film portion supported by the support frame portion is formed. It is preferable to process the back surface of the silicon substrate by wet etching from the viewpoint of manufacturing cost and processing time.

For etching the back surface of the silicon substrate, a wet etching mask layer is formed on the back surface of the substrate,
After patterning the wet etching mask layer by lithography, the back surface of the substrate may be immersed in an etchant to perform the etching process on the back surface of the substrate.

At this time, when the front surface and the side surface of the substrate are attacked by the etching liquid on the back surface of the substrate, an etching protection layer may be formed on the front surface and the side surface of the substrate. The wet etching mask layer and the etching protection layer may be formed of the same material or different materials.

Examples of the etching solution for the back surface of the silicon substrate include alkaline aqueous solutions such as KOH and NaOH, alkaline aqueous solutions containing alcohol and the like, and alkaline solutions such as organic alkalis.

The etching temperature is preferably a low temperature of 150 ° C. or lower, more preferably a low temperature of 110 ° C. or lower in order to avoid the influence of thermal stress.
Examples of the etching method include a dipping (dipping) method.

As the wet etching mask layer formed on the back surface of the substrate, SiO ₂ , SiC, SiN, Si 3 N is used.
4, Sialon (composite mixture of Si and Al), SiON
Inorganic layers such as

As the wet etching mask layer, simple metals such as tungsten, zirconium, titanium, chromium and nickel, alloys containing these metals, or at least these metals or alloys and oxygen, nitrogen and carbon are used. A metal compound containing one or more elements can be used. These metal systems can be patterned by low temperature wet etching,
Since the removal of these metal-based materials can also be performed by low temperature wet etching at 100 ° C. or lower, damage to the thin film portion does not occur during these treatments.

Examples of the method for forming the wet etching mask layer include thin film forming methods such as a sputtering method, a vapor deposition method and a CVD method. However, if the film quality is poor, the etching solution permeates into the silicon substrate to form a pit (etch pit). It is preferable to control the film forming conditions and the like from the viewpoint of avoiding this, and from the viewpoint of avoiding this because damage such as cracks may occur due to thermal stress and the like during high temperature film formation.

The thickness of the wet etching mask layer is
A range of 0.1 to 1 μm is suitable. If the thickness of the wet etching mask layer is less than 0.1 μm, the silicon substrate cannot be completely covered. If it exceeds 1 μm, it takes a long time to form the film and the influence of the film stress increases.

To pattern the wet etching mask layer, specifically, a resist is applied on the wet etching mask layer, a resist pattern is formed by a lithographic method, and the resist pattern is used as a mask.
The wet etching mask layer is wet-etched with an etching solution and patterned.

The etching solution used for etching the wet etching mask layer is not particularly limited. For example, buffer hydrofluoric acid or the like is used as the etching solution for SiO ₂ .
The etching solution for SiN is hot phosphoric acid, the etching solution for titanium is 4% dilute fluorinated nitric acid aqueous solution, the etching solution for chromium is cerium nitrate / ammonium nitrate / perchloric acid aqueous solution, and the etching of nickel. Examples of the liquid include ferric chloride, and examples of the tungsten etching liquid include an aqueous solution of red blood salt (potassium ferricyanide).

As the etching protection layer formed on the surface and the side surface of the substrate, a metal layer or an inorganic layer used for the above-mentioned wet etching mask layer is used in addition to the resin layer.

Here, for the resin layer, it is preferable to use a resin which is cured at a low temperature of 200 ° C. or lower. If the curing temperature exceeds 200 ° C., the thin film portion may be distorted or damaged due to the thermal stress during the curing process. In order to completely avoid the influence of such heat stress, it is more preferable to use a resin that cures at room temperature.

Examples of the resin include resins containing at least one of fluorine resin, ethylene resin, propylene resin, silicon resin, butadiene resin and styrene resin.

As a method for forming the resin layer on the surface and the side surface of the substrate, a spin coating method, a dipping method, a spraying method and the like can be mentioned, but the spin coating method is preferable in consideration of handling and working efficiency. The coating of the side surface of the substrate is performed, for example, by wrapping the resin around the side surface of the substrate during initial low-speed rotation in the spin coating method.

It is suitable that the thickness of the resin layer is 30 μm or more. When the thickness of the resin layer is less than 30 μm, the durability against the etching solution and the function as the protective layer become poor.

The resin layer can be easily formed by a spin coating method or the like without being affected by heat stress on other portions at the time of forming and removing the resin layer, has excellent step coverage of openings and the like, and is eroded by the etching solution. Can be completely prevented. Therefore, it contributes to manufacturing a transfer mask stably and easily.

Unnecessary layers such as the dry etching mask layer, the wet etching mask layer and the protective layer are finally removed to obtain a transfer mask. Here, each of the wet etching mask layer and the etching mask layer is removed with various etching solutions or the like, and the resin layer or the like is removed with an organic solvent or the like.

[0082]

The present invention will be described in more detail based on the following examples.

Embodiment 1 FIG. 1 is a process explanatory view showing an example of a manufacturing process of a transfer mask of the present invention. As shown in FIG. 1, the SOI substrate 1 (see FIG.
An inorganic layer (SiO ₂ layer or the like) is formed on both surfaces of (a)) (not shown), the inorganic layer is patterned by a lithography technique, and dry etching is performed from the front surface side to form an opening 11, and the back surface is formed. Wet etching is applied from the side to form the thin film portion 13 supported by the support frame portion 12, and the unnecessary inorganic layer is removed with buffer hydrofluoric acid or the like to obtain a transfer mask made of silicon (Fig. 1
(B)).

Then, a diffusion preventing layer 2 made of TiN is formed to a thickness of 0.2 μm on the surface of the obtained transfer mask by a reactive sputtering method, and a conductive layer 3 made of Au is formed thereon to a thickness of 1 μm. To obtain a transfer mask. For the purpose of densifying the diffusion prevention layer, vacuum heat treatment was performed at 700 ° C. for 30 minutes when the diffusion prevention layer made of TiN was formed.

The transfer mask thus obtained was mounted on an electron beam partial batch exposure apparatus, and a drawing test was carried out. As a result, it was confirmed that the transfer mask had a practical durability of about 1,000 hours.

Example 2 A transfer mask was obtained in the same manner as in Example 1 except that the diffusion preventing layer 2 made of TaN was formed instead of TiN.
The use durability of the obtained transfer mask was about 800 hours, which was a practical level.

Examples 3 to 6 Si / TiN was prepared in the same manner as in Examples 1 and 2 except that the conductive layer 3 made of W or Ta was formed instead of Au.
/ W (Example 3), Si / TiN / Ta (Example 4),
Si / TaN / W (Example 5), Si / TaN / Ta
A transfer mask having the configuration of (Example 6) was obtained. The use durability of the obtained transfer mask was about 500 to 1000 hours, which was a practical level.

Comparative Examples 1 to 4 Example 1, except that the diffusion preventing layer 2 was not formed,
Transfer masks were obtained in the same manner as 3, 4, and 7. The use durability of each of the obtained transfer masks was about 5 to 100 hours, which was not a practical level.

Examples 7 to 8 Instead of TiN, TiC (Example 7), C (carbon)
A transfer mask was obtained in the same manner as in Example 1 except that the diffusion prevention layer 2 made of (Example 8) was formed and the conductive layer 3 made of Pt was formed instead of Au. The use durability of each of the obtained transfer masks was 500 hours or more, which was a practical level.

Example 9 A transfer mask was obtained in the same manner as in Example 1 except that a phosphorus (P) -doped silicon substrate was used instead of the SOI substrate. The use durability of the obtained transfer mask was about 1,500 hours, which was a practical level.

Example 10 A transfer mask was obtained in the same manner as in Example 1 except that the heat treatment temperature of the diffusion prevention layer was 500 ° C. The use durability of the obtained transfer mask was about 400 hours.

Example 11 T was deposited between a silicon substrate and a TiN layer by sputtering.
A transfer mask was obtained in the same manner as in Example 1 except that a buffer layer made of i and having a thickness of 0.02 μm was formed. The use durability of the obtained transfer mask was about 1000 hours, which was a practical level.

Embodiment 12 FIG. 2 is a process explanatory view showing another example of the manufacturing process of the transfer mask of the present invention. As shown in FIG. 2, a diffusion preventive layer 2 made of TiN is formed to a thickness of 0.1 μm on the surface of a boron (B) -doped silicon substrate 1 (FIG. 2A) by a sputtering method. A conductive layer 3 made of W was sequentially formed on the upper surface of the substrate to a thickness of 0.8 μm by sputtering (FIG. 2).
(B)). For the purpose of densifying the diffusion prevention layer and the conductive layer, heat treatment was performed at 600 ° C. for 60 minutes at the stage of forming the conductive layer.

[0094] Then, on the conductive layer 3 to form a SiO ₂ layer 4 was subjected to patterning by lithography and a dry etching technique using the SiO ₂ layer 4 a resist (FIG. 2 ( c)).

Then, using the patterned SiO ₂ layer 4 as a mask, the W conductive layer 3 and the TiN diffusion preventing layer 2 are sequentially etched by dry etching, and then the surface of the silicon substrate 1 is trench-etched.
An opening pattern was formed (FIG. 2 (d)). As an etching gas for the W conductive layer 3, a fluorocarbon-based gas (C
F ₄ / O ₂ ) is used, chlorine-based gas (Cl ₂ / O ₂ ) is used as an etching gas for the TiN diffusion prevention layer 2, and Cl ₂ / SF ₆ mixed gas is used as an etching gas for the surface of the silicon substrate 1. did.

Next, a 2000 angstrom thick SiC layer (wet etching mask layer) 5 is formed on the back surface of the substrate 1.
And a rubber-based resin (ethylene / propylene or the like) having a thickness of 300 μm is applied as a protective layer against etching to the surface and side surfaces of the substrate to form a resin layer 6, and the resin layer 6 is heated at 100 ° C. Was cured (FIG. 2 (e)). On the SiC layer 5 formed on the back surface of the substrate 1,
Patterning was performed using a lithography technique using a resist and a dry etching technique (see FIG. 2).
(E)).

Using the patterned SiC layer 5 as a mask, the back surface of the silicon substrate 1 was wet-etched until reaching the opening pattern (FIG. 2 (f)).

Finally, the unnecessary SiC layer 5, Si
The O ₂ layer 4 and the resin layer 6 were removed to obtain a transfer mask (FIG. 2 (f)).

In the above transfer mask, the opening including the conductive layer and the diffusion prevention layer is formed by continuous dry etching. Therefore, it is more accurate than the case where the conductive layer and the diffusion prevention layer are formed after the opening is formed. A transfer mask having various openings could be obtained. The use durability of the obtained transfer mask was about 700 hours, which was a practical level.

Example 13 Diffusion prevention layer 2 made of WC instead of the TiN diffusion prevention layer 2
Was formed, and a transfer mask was obtained in the same manner as in Example 12 except that the conductive layer 3 made of Ir was formed instead of W.
Note that chlorine gas (Cl ₂ ) was used as the etching gas for the iridium layer, chlorine-based gas (Cl ₂ / O ₂ ) was used as the etching gas for the WC diffusion prevention layer, and SiCl ₄ / was used as the etching gas for the silicon substrate surface. SF ₆ / N ₂
A mixed gas was used. The use durability of each of the obtained transfer masks was about 1,000 hours, which was a practical level.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not necessarily limited to the above embodiments.

For example, instead of the SOI substrate, SIMOX
Similar results were obtained using the substrate. Further, when a conductive layer and the like were formed on the mask side surface and the mask back surface in addition to the mask surface, an excellent effect of preventing charge-up was shown.

The transfer mask of the present invention can be used as an electron beam exposure mask, an ion beam exposure mask, an X-ray exposure mask, and the like.

[0104]

As described above, the transfer mask of the present invention has a long durability and has a practical level of service durability.

[Brief description of drawings]

FIG. 1 is a process explanatory view showing an example of a manufacturing process of a transfer mask of the present invention.

FIG. 2 is a process explanatory view showing another example of the manufacturing process of the transfer mask of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2 Diffusion prevention layer 3 Conductive layer 4 SiO ₂ layer (dry etching mask layer) 5 Wet etching mask layer 6 Resin layer 11 Opening 12 Support frame part 13 Thin film part

Claims (6)

[Claims] 1. A transfer mask having an opening formed in a thin film portion supported by a support frame portion, wherein a conductive layer is formed on a surface of the transfer mask, wherein the transfer mask has a surface between the surface and the conductive layer. A transfer mask, wherein a diffusion prevention layer is provided on the. 2. The transfer mask according to claim 1, wherein the diffusion prevention layer is made of a conductive material. 3. The conductive material forming the diffusion prevention layer,
Metal carbide of any metal selected from W, Zr, Ta, Mo, Ti, Nb, or Zr, Ta, Mo, T
The transfer mask according to claim 2, which is a metal nitride of any metal selected from i and Nb. 4. The transfer mask according to claim 2, wherein the conductive material forming the diffusion prevention layer is carbon. 5. The transfer mask according to claim 1, wherein the diffusion preventing layer is heat-treated to form a dense film having a high diffusion preventing function. 6. A transfer mask in which an opening is formed in a thin film portion supported by a support frame portion, wherein a conductive layer is formed on a surface of the transfer mask, wherein the transfer mask has a surface between the surface and the conductive layer. A buffer layer for relaxing stress between these layers, or a buffer layer for relaxing stress between these layers between the diffusion prevention layer and the transfer mask surface and / or the conductive layer. Transfer mask.