JPH08240904A - Transfer mask and its production - Google Patents

Abstract

PURPOSE: To obtain a mask having excellent stability and durability and high aperture accuracy and transfer accuracy without deterioration due to peeling of films or diffusion by forming a supporting frame part, a metal thin film part supported by the supporting frame part, and an aperture formed in the metal thin film part. CONSTITUTION: First, an etching stopper metal layer 2, a thin film metal part 3 and a SiO2 layer 4 are formed on the surface of a substrate 1. Then, the back surface of the substrate 1 is etched to the metal layer 2 while a supporting frame part 11 is left so that a thin film part 12 of the metal layer 2/metal layer 3 structure supported by the supporting frame part 11 is formed. Then, the SiO2 layer is patterned with a resist, and after the resist is removed, the patterned SiO2 layer 4 is used as a mask to perform perpendicular etching of the metal layer 3 to form an aperture pattern 13. By this method, a process to form a conductive layer which is generally used can be eliminated. Since no SiO2 intermediate layer is present, the obtd. mask has excellent heat radiating characteristics and high accuracy for the aperture and transfer can be obtd.

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 and a method for manufacturing the same.

[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.

Under such circumstances, Si, Mo and A are used as masks for electron beam exposure, ion beam exposure and X-ray exposure.
A transfer mask (Stencil mask) in which a pattern to be exposed is formed by forming holes (through holes, openings) in a metal foil such as l or Au is being developed and partially put into practical use, but it is difficult to manufacture. It has not been put to practical use for mass production.

Particularly, in electron beam lithography for drawing a pattern using an electron beam, it corresponds to each portion obtained by dividing a pattern to be exposed, which is called partial batch exposure, block exposure or cell projection exposure. Using a mask with various transmissive figures (apertures) formed, an electron beam is shaped through these apertures, and a given section (block or cell) is partially exposed at once, and this operation is repeated to perform drawing. A drawing method has been proposed in recent years, and has rapidly emerged as the next-generation LSI technology and is in the spotlight. This drawing method by partial batch exposure is a direct drawing method in which an exposure pattern is scanned with an electron beam (narrow beam spot) that has already been put into practical use (a so-called one-stroke writing method).
This method was devised to deal with the problem that the drawing time was extremely long and the throughput was low, and high-speed drawing is possible even compared with the direct drawing method using a variable rectangle.

Transfer masks used for such partial batch exposure have been conventionally manufactured by various methods.
Generally, a silicon substrate (such as a commercially available silicon wafer) is processed and manufactured in terms of workability and strength. Specifically, for example, the back surface of the silicon substrate is etched while leaving the support frame portion to form a support frame portion and a thin film portion supported by this support frame portion, and an opening is formed in this thin film portion. A transfer mask is produced. Further, when the back surface of the silicon substrate is etched to form the thin film portion supported by the support frame portion, an SOI (Silicon on Insulator) substrate having a structure in which _two silicon plates are bonded together via a SiO ₂ layer is used. , A method of forming a silicon thin film portion using a SiO ₂ layer as an etching stop layer (etching stopper layer) is known (Japanese Patent Laid-Open No. 6-130655) and is effective as a method of forming a uniform silicon thin film portion. .

Considering the durability of the thin film portion at the time of manufacturing the transfer mask and the processing accuracy of the opening, an SOI substrate is used as the substrate, and the opening pattern portion is processed with high accuracy by dry etching to correspond to the opening portion. A general method is to process the back surface portion of the formed substrate by wet etching (wet etching). More specifically, for example, an SOI substrate having a Si / SiO ₂ / Si multi-layer structure is used, and S is formed on the opening pattern formation surface side of the SOI substrate.
After forming the dry etching (trench etching) mask layer made of iO _2, covering the entire substrate with a silicon nitride layer, a thin film portion is processed by wet etching the substrate rear surface to form an opening in the rear surface portion of the silicon nitride layer A method is known in which, after forming and removing the silicon nitride layer, dry etching is performed on the opening pattern side.

On the contrary, by changing the order of the steps, the opening pattern is processed first, and then the back surface of the substrate is processed, or a method of using a boron layer as an etching stopper layer (Japanese Patent Laid-Open No. 2-76216). No.) are also proposed.

In the above-mentioned transfer mask made of silicon or the like, the silicon thin film portion in which the opening is formed is poor in durability against an electron beam as it is, and therefore gold (Au), tungsten ( A metal layer such as W) or platinum (Pt) is formed to improve the durability of the mask during electron beam irradiation. Also, these metals are
Since it is a good conductor and has excellent electronic conductivity and thermal conductivity, it contributes to the prevention of beam shift due to charging (charge-up) and the thermal distortion of the mask due to heat generation. Furthermore, since these metals have excellent shielding properties against electron beams and act as energy absorbers, the silicon thin film portion can be made thin, and therefore the aperture accuracy can be improved and the side wall of the aperture can affect the electron beams. Can be reduced.

[0009]

However, the above-mentioned conventional transfer mask has the following problems.

That is, in a transfer mask in which a metal layer is formed on a silicon thin film portion, the coefficient of linear expansion of the metal layer is significantly different from that of silicon, which is the base, so that the mask is distorted by thermal stress during electron beam irradiation. There is a problem that the transfer accuracy may be deteriorated or the metal layer may be peeled off, resulting in lack of stability and durability of the mask. In addition, when the electron beam is irradiated, metal atoms in the metal layer cause a diffusion reaction to diffuse into silicon, and the silicon thin film portion and the support frame portion are deteriorated, so that there is a problem that the mask lacks stability and durability.

Further, the silicon thin film portion usually has a thickness of about 20 μm, and in order to form an opening in the silicon thin film portion, a trench etching (a technique of digging a deep groove) is required. Since the above is difficult, there is a problem in that the opening accuracy is impaired. further,
Since the depth of the opening is deep (long), there is a problem that the electron beam passing through the opening is affected by the side wall of the opening and a beam shift occurs to deteriorate the transfer accuracy.

On the other hand, in a transfer mask manufactured using an SOI substrate, Si is provided between the support frame portion and the silicon thin film portion.
Since the O ₂ layer is interposed, the metal layer is insulated by the SiO ₂ layer, which causes a problem of charge-up.
In addition, since the SiO ₂ layer has poor thermal conductivity, there is a problem that the heat radiation property is poor and the transfer accuracy is deteriorated. In order to prevent charge-up, since the transfer mask and the mask holder are grounded, it is necessary to conduct electricity with silver paste or the like, which causes a problem that the work is complicated. further,
SOI substrates are more expensive than bare silicon, which is
This is because bubbles are likely to be generated at the interface between the i thin film portion and the SiO ₂ and the yield in manufacturing the SOI substrate is low.

The present invention has been made in view of the above-mentioned problems, and provides a transfer mask having high opening accuracy and transfer accuracy as well as excellent stability and durability without deterioration due to film peeling or diffusion reaction. The first purpose. A second object is to provide a transfer mask having excellent electron conductivity and thermal conductivity, and excellent transfer accuracy and durability. A third object is to provide a method of manufacturing a transfer mask that is simpler and less expensive than conventional methods.

[0014]

In order to achieve the above object, a transfer mask of the present invention is provided with a support frame portion, a metal thin film portion supported by the support frame portion, and an opening formed in the metal thin film portion. Or a support frame portion, a metal thin film portion supported by the support frame portion, an opening formed in the metal thin film portion, and the support frame portion and the metal thin film portion. It is configured to have another metal layer.

In the transfer mask of the present invention, in the transfer mask, the metal thin film portion is Ta, Re, W or I.
r, Pt, Hf, Pd, Rh, Mo, Cu, Au, N
b, Ru, Zr, any of the metals, alloys containing these metals, or compounds containing these metals, and / or the other metal layer is Mo,
The structure is made of a metal such as W, Zn, Ti, Zr, or Nb, an alloy containing these metals, or a compound containing these metals. Further, the transfer mask manufacturing method of the present invention includes a step of forming a metal layer on a substrate, and a metal supported on the support frame portion by etching the back surface of the substrate until the metal layer is left while leaving the support frame portion. A structure including a step of forming a thin film portion and a step of forming an opening in a metal layer or a metal thin film portion on a substrate, or a step of forming an etching stopper metal layer on a substrate, and a step of forming an etching stopper metal layer on the etching stopper metal layer. A step of forming a thin film metal layer and a step of forming an etching stopper metal layer / metal thin film portion supported by the support frame by etching the back surface of the substrate until it reaches the etching stopper metal layer leaving the support frame. And a step of forming an opening in the thin film portion metal layer or the metal thin film portion on the substrate, and a step of removing the etching stopper metal layer.

[0016]

In the transfer mask of the present invention, since the thin film portion of the mask is composed of only the metal thin film portion without the silicon thin film portion, the conductive layer forming step which is generally used can be omitted and the intermediate SiO 2 layer can be omitted. Excellent heat dissipation characteristics because there are no _two layers. In addition, since the metal thin film portion has a density about 10 times that of silicon, the thickness of the silicon thin film portion is 2 to 3 μm (usually 20 μm).
It is possible to make the thickness smaller than that of (m) and therefore has high opening accuracy and transfer accuracy.

Further, SiO is provided between the support frame portion and the metal thin film portion.
_Since there are no _two layers interposed, it has excellent electronic and thermal conductivity,
Excellent transfer accuracy and durability.

Furthermore, the transfer mask manufacturing method of the present invention does not require steps such as forming a silicon thin film portion, forming an opening in the silicon thin film portion (difficult), and forming a metal conductive layer on the silicon thin film portion. The transfer mask can be manufactured easily and inexpensively as compared with the conventional one.

The present invention will be described in detail below. The transfer mask of the present invention includes a support frame portion, a metal thin film portion supported by the support frame portion, an opening formed in the metal thin film portion, and if necessary, between the support frame portion and the metal thin film portion. And another metal layer interposed therebetween.

Here, the support frame portion is usually formed by etching the back surface of the silicon substrate or the like, leaving the support frame portion. Substrate materials include Si, Mo, Al, Au, Cu
Etc., but from the viewpoint of chemical resistance, processing conditions, dimensional accuracy, etc., it is preferable to use a silicon substrate, a silicon substrate doped with phosphorus or boron, or the like. When a silicon substrate doped with phosphorus or boron is used, the electron conductivity of the silicon substrate can be improved.

Materials for forming the metal thin film portion are Ta (tantalum), Re (rhenium), W (tungsten), and I.
r (iridium), Pt (platinum), Hf (hafnium), Pd (palladium), Rh (rhodium), Mo
Examples of the metal include (molybdenum), Cu (copper), Au (gold), Nb (niobium), Ru (ruthenium), and Zr (zirconium). The metal thin film portion is an alloy containing these metals (including intermetallic compounds), or a compound containing these metals (eg, oxides, nitrides, carbides, etc.).
Etc. Further, the metal thin film portion may have a multi-layered structure to prevent the surface from being oxidized and to improve the adhesion to the substrate.

The thickness of the metal thin film portion is 0.5 to 5 μm from the viewpoints of electron beam durability, film stress, manufacturing period, and the like.
The degree is about 2 to 3 μm, more preferably about 3 μm. When the thickness of the metal thin film portion is less than 0.5 μm, the durability and the shielding property against the electron beam are poor, and when it exceeds 5 μm, it takes a long time to form and it is difficult to control the film stress.

The method of forming the metal thin film is not particularly limited,
Various thin film forming methods can be used. Examples of the thin film forming method include thin film forming methods such as a sputtering method, a vacuum vapor deposition method, an ion beam vapor deposition method, a CVD method, an ion plating method, an electrodeposition method, and a plating method. The method for forming the metal thin film is appropriately selected in consideration of film quality (film density, crystal structure, defect-free property, etc.), cost, and the like.

The metal thin film portion supported by the support frame portion is usually formed by forming the metal thin film on the substrate by the above-mentioned thin film forming method and then etching the back surface of the substrate leaving the support frame portion. .

As a method of forming the opening in the metal thin film portion, an etching method, a lift-off method or the like can be mentioned. Here, the etching method includes wet etching and dry etching. In order to form a highly accurate opening, dry etching is preferable, and in order to prevent redeposition of an etching substance, reactive ion etching ( It is preferable to use RIE) or ion beam etching. In the case of adopting dry etching, the metal thin film portion can be dry-etched with Ta, Re, W, Ir or the like, and is composed of a metal having a specific gravity of 15 g / cc or more from the viewpoint of the electron beam shielding effect. Preferably.

On the other hand, in the lift-off method, after forming a lift-off pattern having the same shape as the opening made of a lift-off material by a lithography technique in a portion to be an opening on the substrate, a metal thin film layer is formed on the substrate and then lift-off is performed. This is a method of removing a pattern to form a metal thin film layer having openings.

Here, as a method for forming the metal thin film layer on the substrate, for example, a dry thin film forming method such as a sputtering method, a vacuum evaporation method, an ion beam evaporation method, a CVD method, an ion plating method, or electrodeposition. And a wet thin film forming method such as a plating method.

As the lift-off material, patternable materials such as resist, photosensitive glass, photosensitive SOG (spin-on-glass), photosensitive resin film and the like can be mentioned.

The thickness of the lift-off pattern is preferably about 1.5 times the thickness of the metal thin film layer. this is,
This is because if the thickness is smaller than this thickness, the pattern dimension accuracy is lowered due to the wraparound.

When the dry thin film forming method is adopted, the metal thin film portion is made of W, Ir, Pt, Re, Ta, Hf, Pd, R from the viewpoint of density, chemical resistance, film forming characteristics and the like.
It is preferable to use a metal such as h, Mo, Cu, Ag, Nb, and Au. When the wet thin film forming method is adopted, the metal thin film portion is formed of P from the viewpoint of density, deposition rate, and the like.
It is preferably composed of a metal such as t, Pd, Rh, Ru, Zn, or Au.

In the present invention, another metal layer (etching stopper metal layer) is provided if necessary. This other metal layer functions as an etching stopper layer in the mask forming process and remains between the supporting frame portion and the metal thin film portion after forming the mask, but does not reduce the electron conductivity or thermal conductivity of the mask. . Further, the other metal layer acts as a diffusion preventing layer between the support frame portion and the metal thin film portion after forming the mask, and improves the stability and durability of the mask.

The other metal layer (etching stopper metal layer) may be any metal as long as the metal forming the metal thin film portion has excellent chemical resistance to a hot alkaline aqueous solution (etching solution on the back surface of the silicon substrate). It does not necessarily have to be provided. That is, the wet etching stopper metal layer is formed in the case where the metal constituting the metal thin film portion is excellent in electron beam irradiation durability but poor in durability against hot alkali and is corroded as it is, such as Ta. The other metal layer also functions as a dry etching stopper layer. In this case, the other metal layer serves as a dry etching stopper layer when dry etching the metal thin film portion (because the etching rates of the two are different), and also plays a role of detecting the end point of the dry etching of the metal thin film portion. Achieve (because other metal layer components can be detected to detect the end point of dry etching).

The other metal layer is a metal other than the metal forming the metal thin film portion, does not dissolve in an alkaline solution which is an etching solution of silicon, and can be easily removed by another wet etching solution. Any non-magnetic metal having good electronic conductivity and thermal conductivity may be used. Specific examples include metals such as Mo, W, Zn, Ti, Zr, and Nb, alloys containing these metals, and compounds containing these metals.

The method of forming the other metal layers is the same as the method of forming the metal thin film described above.

Next, a method of manufacturing the transfer mask of the present invention will be described. The transfer mask manufacturing method of the present invention comprises a step (arbitrary) of forming an etching stopper metal layer on a substrate, a step of forming a thin film portion metal layer on the etching stopper metal layer, and a support frame portion on the back surface of the substrate. Etching process to leave the etching stopper metal layer remaining to form the etching stopper metal layer / metal thin film portion supported by the support frame portion, a step of forming an opening in the metal thin film portion on the substrate, and etching And a step of removing the stopper metal layer.

FIG. 1 is a process explanatory view showing an example of a transfer mask manufacturing process. As shown in FIG. 1, first, an etching stopper metal layer 2 and a thin film portion metal layer 3 are formed on the surface of a substrate 1.
Are formed (FIG. 1A). The method and materials for forming the etching stopper metal layer 2 and the thin film portion metal layer 3 have been described above.

When the thin-film metal layer 3 is formed by the electrodeposition method or the plating method, the electrode layer (Al, Cu, Ag) for electrodeposition or plating is formed on the etching stopper metal layer.
Etc.) and the thin film portion metal layer may be formed on the electrode layer by energizing the electrode layer.

Next, the back surface of the substrate 1 is etched until the etching stopper metal layer 2 is left, leaving the supporting frame portion, to form an etching stopper metal layer / metal thin film portion supported by the supporting frame portion (FIG. 1). (B)).

Here, in order to etch the back surface of the substrate while leaving the supporting frame portion, a wet etching mask layer is formed on the back surface of the substrate, and the wet etching mask layer is patterned by a lithography technique to etch the back surface of the substrate with an etching solution. Then, the back surface of the substrate may be etched. 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.

As the etching solution for the back surface of the substrate, KO is used.
Examples thereof include an alkaline aqueous solution such as H and NaOH, an alkaline aqueous solution containing alcohol and the like, and an alkaline solution such as an organic alkali.

The etching temperature is preferably a low temperature of 150 ° C. or lower, and 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 method.

In the above manufacturing method, as the wet etching mask layer formed on the back surface of the substrate, simple metals such as tungsten, zirconium, titanium, chromium and nickel, alloys containing these metals, or these metals or alloys and oxygen are used. It is preferable to use a metal compound containing at least one element selected from nitrogen, carbon, and carbon. This is because these metal systems can be patterned by low temperature wet etching, and the removal of these metal systems can also be performed by low temperature wet etching at 100 ° C. or less, so that the thin film portion is damaged during these processes. This is because no such problem occurs.

As the wet etching mask layer, it is also possible to use an inorganic layer such as SiO ₂ , SiC, SiN, Si 3 N 4, sialon (a composite mixture of Si and Al) or SiON.

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). The sputtering method or the CVD method is preferable from the viewpoint of avoiding this because it occurs, and from the viewpoint of avoiding this because damage such as cracks may occur due to thermal stress or 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 onto 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, the etching solution for titanium is 4% diluted fluorinated nitric acid aqueous solution, and the etching solution for chromium is ceric ammonium nitrate. / Aqueous perchloric acid, etc., ferric chloride, etc. as etching solution for nickel, red blood salt (potassium ferricyanide) as etching solution for tungsten
An aqueous solution or the like, buffer hydrofluoric acid or the like can be used as the etching solution for SiO ₂ , and hot phosphoric acid or the like can be used as the etching solution for SiN.

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, as 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 a resin containing at least one of a fluorine resin, an ethylene resin, a propylene resin, a silicon resin, a butadiene resin, and a styrene resin.

As a method of forming the resin layer on the surface and the side surface of the substrate, a spin coating method, a dipping method, a spray 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 by causing the resin to wrap around the side surface of the substrate during the initial low speed rotation in the spin coating method.

The thickness of the resin layer is preferably 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 thermal stress on other portions at the time of forming and removing the resin layer, and has excellent step coverage.
It is possible to completely prevent erosion of the etching liquid. Therefore, it contributes to manufacturing a transfer mask stably and easily.

Next, an opening is formed in the metal thin film portion. Examples of the method of forming the opening include the above-described etching of the metal layer of the film part or the lift-off method. When forming an opening in the metal thin film part by dry etching,
First, a SiO ₂ layer (dry etching mask layer) 4 is formed on the thin film portion metal layer 3 (FIG. 1C).

As the method for forming the SiO ₂ layer 4, thin film formation such as a sputtering method, a vapor deposition method, a thermal oxidation method, a CVD method, a method using SOG (spin on glass), a photosensitive glass, a photosensitive SOG, or the like. There is a method.

Instead of the SiO ₂ layer 4, a SiC layer, Si 3
N4 layer, Sialon (composite mixture of Si and Al) layer, S
An inorganic layer such as an iON layer, a metal such as tungsten, zirconium, titanium, chromium, nickel, an alloy containing these metals, or a metal layer such as a metal compound of these metals or alloys with oxygen, nitrogen, carbon, etc. You may use.

Next, the SiO ₂ layer 4 is patterned into a desired shape by using a lithographic technique. Specifically, for example, a resist is applied on the SiO ₂ layer 4, a resist pattern (not shown) is formed by exposure and development, and the SiO ₂ layer 4 is used as a mask.
Of the SiO ₂ layer 4 by etching
(FIG. 1 (c)). In this case, in consideration of the pattern accuracy, the etching of the SiO ₂ layer 4 is performed using fluorocarbon-based gas (SF ₆ / O ₂ , CF ₄ / O ₂ , C ₂ F ₆ / O).
It is preferable to perform dry etching using ₂ ) as an etching gas.

Next, after removing the resist, the thin-film metal layer 3 is dry-etched by dry etching using the patterned SiO ₂ layer 4 as a mask.
The iO ₂ pattern is transferred to these to form openings (FIG. 1D).

Here, the etching gas used for dry etching is not particularly limited, but for example, the etching gas for Ta is Cl ₂ gas or Cl ₂ / SiCl ₄ / N ₂
A mixed gas such as CF ₄ / O ₂ is used as an etching gas for W.
A mixed gas such as CF ₄ / is used as an etching gas for Mo.
O ₂ mixed gas and the like can be mentioned.

On the other hand, in the case of forming an opening in the metal thin film portion by the lift-off method, as shown in FIG. 2C, a lift-off pattern (image) made of a lift-off material is previously formed at the opening forming position of the thin-film metal layer 3. 5 is formed,
The lift-off pattern 5 in the opening of the thin-film metal layer 3 is removed to form an opening.

Finally, the unnecessary layer is removed to obtain a transfer mask. Here, the etching stopper metal layer, the lift-off pattern made of a lift-off material, the wet etching mask layer and the dry etching mask layer are removed by various etching solutions or the like, and the resin layer is removed by an organic solvent or the like.

Although the transfer mask manufacturing method of the present invention includes a plurality of steps as described above, the order of these steps is not limited, and the step order can be arbitrarily determined according to the purpose. It is possible and has a high degree of freedom For example, the opening can be formed first and the back surface can be processed later.

[0063]

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, a thickness of 0.2 μm is formed on the surface of a silicon substrate 1 having a thickness of 500 μm by a sputtering method.
m Zr layer (etching stopper layer) 2 is formed, a Ta layer 3 having a thickness of 3 μm is formed thereon by a sputtering method, and further, a Ta layer 3 having a thickness of 3 μm is formed on the Ta layer 3 by a sputtering method.
The SiO2 layer 4 was formed (FIG. 1 (a)).

Then, a SiN layer is formed on the back surface of the substrate (not shown), and this SiN layer is patterned by a lithography method using a resist. Using this patterned back SiN layer as a mask, a KOH aqueous solution is used. The back surface of the substrate 1 is etched into a predetermined size and shape to form the support frame portion 11 and the thin film portion 12 (see FIG. 1).
(B)). In this case, the Zr layer acts as an etching stopper layer for the KOH aqueous solution.

Subsequently, the surface SiO ₂ layer 4 was patterned by using a lithography technique using a resist and a dry etching technique (FIG. 1C).

After removing the resist, the Ta layer 3 was vertically etched by magnetron reactive ion etching (RIE) using the patterned SiO ₂ layer 4 as a mask to form an opening pattern 13 (see FIG. 1 (d)). As the etching gas, Cl
_Two gases were used.

Finally, Zr of the unnecessary thin film portion region
The layer 2 is removed with an aqueous cupric chloride solution, the SiO ₂ layer 4 is removed with buffered hydrofluoric acid, and the back surface SiN layer is removed with hot phosphoric acid.
A transfer mask was obtained (FIG. 1 (e)).

The obtained transfer mask was mounted on an electron beam collective exposure apparatus, and a drawing test was carried out. As a result, there was no deterioration due to film peeling or diffusion reaction, excellent stability and durability, and excellent electron conductivity and thermal conductivity. It was confirmed that it is excellent and has high opening accuracy and transfer accuracy, and is highly practical.

Embodiment 2 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, on the surface of the silicon substrate 1 having a thickness of 500 μm, the thickness of 0.2 is formed by the sputtering method.
forming a Ti layer (etching stopper layer) 2 of μm,
A SiO2 layer 4 having a thickness of 5 μm was formed thereon by a sputtering method (FIG. 2 (a)).

Subsequently, a resist layer is formed on the SiO ₂ layer 4, a resist (negative) pattern is formed by a lithography technique (not shown), and the SiO ₂ layer 4 is dry-etched using this resist pattern as a mask.
Then, the lift-off pattern 5 was formed (FIG. 2B). A CF ₄ / H ₂ mixed gas was used as an etching gas for the SiO ₂ layer 4.

After removing the resist, a Pt layer (thin film metal layer) 3 having a thickness of 4 μm was formed by a vacuum evaporation method (FIG. 2).
(C)).

Then, on the back surface of the substrate 1, N having a thickness of 0.5 μm is formed.
The i-layer (etching mask layer) 6 is formed, and a rubber-based resin (ethylene-propylene-based resin or the like) 300 is formed on the surface and side surfaces of the substrate as a protective layer against etching.
The resin layer 7 was formed by coating with a thickness of μm, and heated at 150 ° C. to cure the resin layer 7 (FIG. 2D).

Next, the Ni layer 6 is patterned by lithography using a resist and wet etching using a second aqueous solution of chloride, and the back surface Ni layer 6 thus patterned is used as a mask to heat the aqueous KOH solution at 90 ° C. Allows the back surface of the substrate 1 to have a predetermined size,
The support frame portion and the thin film portion were formed by etching into a shape (FIG. 2E). In this case, the Ti layer 2 is KO
It acts as an etching stopper layer for the H aqueous solution.

Finally, the Ti layer 2 in the exposed exposed thin film portion region is removed with hot sulfuric acid, the Ni layer 6 is removed with a second aqueous solution of chloride, the resin layer 7 is removed with a solvent, and the lift-off pattern is used. 5 (SiO ₂ ) was removed (lifted off) with buffered hydrofluoric acid to obtain a transfer mask (FIG. 2 (f)).

The resin layer 7 was able to completely prevent erosion of the etching solution during the wet etching of the back surface of the substrate. In addition, the influence of heat stress can be avoided throughout the entire process, and the transfer mask can be stably manufactured without any damage or the like during the process.

The transfer mask thus obtained was attached to an electron beam collective exposure apparatus and a drawing test was carried out. As a result, there was no deterioration due to film peeling or diffusion reaction, excellent stability and durability, and excellent electron conductivity and thermal conductivity. It was confirmed that it is excellent and has high opening accuracy and transfer accuracy, and is highly practical.

Embodiment 3 FIG. 3 is a process explanatory view showing another example of the manufacturing process of the transfer mask of the present invention. As shown in FIG. 3, a thickness of 0.0 μm was formed on the surface of the silicon substrate 1 having a thickness of 500 μm by a sputtering method.
An Ag layer (electrode layer) 2 having a thickness of 5 μm was formed, and a photosensitive glass layer 4 having a thickness of 10 μm was formed thereon by spin coating (FIG. 3A).

Subsequently, the photosensitive glass layer 4 was patterned by a lithography technique to form a lift-off pattern 5 (FIG. 3 (d)).

Next, a 7 μm thick A film was formed by electrolytic plating.
The u layer (thin film metal layer) 3 was formed on the Ag layer (electrode layer) (FIG. 3C).

Then, the SiN layer 6 is formed on the entire substrate 1 (front surface, back surface and side surfaces of the substrate) as a protective layer against etching.
Was formed with a thickness of 1.0 μm (FIG. 3D).

Next, the back surface SiN layer 6 is patterned by a lithography method using a resist and wet etching using hot phosphoric acid, and the KOH aqueous solution heated to 90 ° C. is masked with the patterned back surface SiN layer 6. Thus, the back surface of the substrate 1 was etched into a predetermined size and shape to form a support frame portion and a thin film portion (FIG. 3E). In this case, the Ag layer 2 in the thin film region is simultaneously removed by the KOH aqueous solution.

Finally, the unnecessary SiN layer 6 is removed by hot phosphoric acid, and the lift-off pattern 5 (photosensitive glass) is formed.
Was removed (lifted off) with buffered hydrofluoric acid to obtain a transfer mask (FIG. 3 (f)).

The transfer mask thus obtained was attached to an electron beam collective exposure apparatus, and a drawing test was conducted. As a result, film peeling and deterioration due to a diffusion reaction were not observed, and stability and durability were excellent, and electron transfer and thermal conductivity were improved. It was confirmed that it is excellent and has high opening accuracy and transfer accuracy, and is highly practical.

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, P or B instead of a silicon substrate
Similar results were obtained using a doped silicon substrate.

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

[0087]

As described above, the transfer mask of the present invention can omit a generally used conductive layer forming step and has excellent heat dissipation characteristics because of the absence of an intermediate SiO ₂ layer, and has a high opening accuracy. And has transfer accuracy.

Further, the transfer mask of the present invention is excellent in electron conductivity and thermal conductivity, and is excellent in transfer accuracy and durability.

Further, the transfer mask manufacturing method of the present invention can manufacture the transfer mask more easily and cheaply than the conventional method.

[Brief description of drawings]

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

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

FIG. 3 is a process explanatory view showing another example of the manufacturing process of the transfer mask according to the present invention.

[Explanation of symbols]

1 Substrate 2 Etching Stopper Metal Layer 3 Thin Film Metal Layer 4 SiO ₂ Layer 5 Lift-off Pattern 6 Etching Mask Layer 7 Resin Layer 11 Support Frame 12 Thin Film 13 Opening Pattern

Claims (6)

[Claims] 1. A transfer mask having a support frame portion, a metal thin film portion supported by the support frame portion, and an opening formed in the metal thin film portion. 2. A support frame part, a metal thin film part supported by the support frame part, an opening formed in the metal thin film part, and another interposing between the support frame part and the metal thin film part. A transfer mask having a metal layer. 3. The metal thin film portion comprises Ta, Re, W, I
r, Pt, Hf, Pd, Rh, Mo, Cu, Au, N
3. The transfer mask according to claim 1, wherein the transfer mask is made of any one of b, Ru, and Zr, an alloy containing these metals, or a compound containing these metals. 4. The other metal layer is Mo, W, Zn, T
4. The transfer mask according to claim 2, wherein the transfer mask is made of a metal such as i, Zr, or Nb, an alloy containing these metals, or a compound containing these metals. 5. A step of forming a metal layer on a substrate, and a step of etching the rear surface of the substrate until the metal layer is left, leaving a support frame portion, to form a metal thin film portion supported by the support frame portion. And a step of forming an opening in a metal layer or a metal thin film portion on the substrate, the method of manufacturing a transfer mask. 6. A step of forming an etching stopper metal layer on a substrate, a step of forming a thin film portion metal layer on the etching stopper metal layer, and a rear surface of the substrate reaching the etching stopper metal layer leaving a supporting frame portion. Etching process to form an etching stopper metal layer / metal thin film portion supported by the supporting frame portion, a step of forming an opening in the thin film portion metal layer or the metal thin film portion on the substrate, and an etching stopper metal layer And a step of removing the transfer mask.