JPH08184955A - Production of transfer mask - Google Patents

Abstract

PURPOSE: To provide a process for producing a transfer mask capable of easily and stably producing the transfer mask having opening patterns of high accuracy at a low cost. CONSTITUTION: This process for producing the transfer mask includes a stage for forming supporting frame parts and thin-film parts supported in supporting frame parts by etching the rear surface of a substrate and a stage for forming through-holes in the thin-film parts. The process includes a stage for forming a conductive layer 2 on the surface of the substrate 1, a stage for forming an etching mask layer (SiO2 layer 3) of the conductive layer 2, a stage for patterning the etching mask layer 3 formed on the conductive layer 2 to desired shapes by using a lithography technique and a stage for continuously working the surface of the conductive layer 2 and the substrate 1 to desired depths by a dry etching technique using the patterned etching mask layer 3 as a mask.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a transfer mask.

[0002]

2. Description of the Related Art At present, electron beam lithography, ion beam lithography, X-ray lithography, etc. are attracting attention as a manufacturing technology for the next-generation ultra-fine element in the sub-half micron region or quarter micron region. It is still uncertain whether it will become the mainstream.

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; St) in which a pattern to be exposed is formed by forming holes (openings) in a metal foil such as l or Au.
(encil mask) has been developed and partially put into practical use, but it has not been put to practical use in 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 transmission-type figures (openings) formed, an electron beam is formed in these openings, and a specified section (block or cell) is partially exposed at once, and this operation is repeated to draw. A drawing method has been proposed.
The drawing method by partial batch exposure has a problem that the drawing time, which has been a problem in the direct drawing method (so-called one-stroke writing method) that scans the exposure pattern with an electron beam (narrow beam spot) that has already been put to practical use This method was devised to cope with the long and low throughput, and enables higher-speed drawing than the direct drawing method using variable rectangles.

Various methods of manufacturing a transfer mask used for such partial batch exposure have been studied. For example, a method of forming a silicon thin film portion using an SOI (Silicon on Insulator) substrate having a structure in which _two silicon plates are bonded together via an SiO ₂ layer and using the SiO ₂ layer as an etching stop layer (etching stopper layer) ( JP-A-6-130655), a method of forming an opening (opening) pattern portion by electric discharge machining using a silicon substrate (JP-A-5-217876), or coating a photosensitive glass on a silicon substrate. A method has been proposed in which this photosensitive glass is used as it is as a mask material to omit the resist process (Japanese Patent Laid-Open No. 4-240719).

Among these various manufacturing methods, in consideration of the durability of the thin film portion at the time of manufacturing the transfer mask and the processing precision of the opening, the SOI substrate is used as the substrate and the opening pattern portion is processed with high accuracy by dry etching. Then
A general method is to process the back surface portion of the substrate corresponding to the opening by wet etching (wet etching). More specifically, for example, Si / SiO ₂ / Si
After using an SOI substrate having a multilayer structure of, and forming a dry etching (trench etching) mask layer made of SiO ₂ on the opening pattern forming surface side of the SOI substrate,
The entire substrate is covered with a silicon nitride layer, an opening is formed in the back surface of this silicon nitride layer, the back surface of the substrate is processed by wet etching to form a thin film part, and the silicon nitride layer is removed, followed by dry etching on the opening pattern side. A method of processing has been proposed.

On the contrary, a method has also been proposed in which the process sequence is changed, the opening pattern is processed first, and then the back surface of the substrate is processed. Furthermore, a method using a boron layer as an etching stopper layer has also been proposed (Japanese Patent Laid-Open No. 2-76216, etc.).

In the conventional transfer mask manufactured as described above, the silicon thin film portion in which the opening is formed is poor in durability against an electron beam and is inferior in heat dissipation property as it is. A metal conductive layer is formed on the surface to improve the heat dissipation characteristics and durability of the mask during electron beam irradiation.

[0009]

However, in the above-mentioned conventional method of manufacturing a transfer mask, generally, after forming an opening, a metal conductive layer is formed by a vacuum thin film forming method such as a sputtering method, a vapor deposition method or a CVD method. Since it is formed, there are the following problems. That is, in the method of forming the metal conductive layer by the sputtering method after forming the opening, the shape of the metal conductive layer at the opening edge portion is the base because the mean free path of molecules during film formation is short in the sputtering method. However, there is a problem that the silicon thin film becomes an overhang state and the opening accuracy is impaired. Further, in the method of forming the metal conductive layer by the vapor deposition method or the CVD method after forming the opening, it is difficult to control the film stress of the formed metal conductive layer, and in addition to the influence of this film stress, the CVD method Generally, a film forming temperature of 250 ° C. or higher is required, and there is a problem that the silicon thin film portion as the base is distorted or damaged due to the influence of the film forming temperature. Further, in the vapor deposition method or the CVD method, the mean free path of molecules during film formation is relatively long and the step coverage is good, so that a film having an uneven thickness is deposited on the side wall of the opening, or the degree of vacuum is increased. 5 × 10 ^-5 to
Under the condition of about rr or less, the opening edge portion is in an overhang state, so that there is a problem that the opening accuracy is deteriorated.

Several measures have been proposed for such problems. For example, after forming an inorganic layer pattern on a silicon substrate, using this inorganic layer pattern as a mask, metal tungsten (metal conductive layer) is selectively deposited on the silicon substrate, the inorganic layer is removed, and the silicon substrate is placed on the back surface side. There is proposed a method of manufacturing a transfer mask in which metal tungsten is directly used as a mask material by dissolving and removing the transfer mask (JP-A-6-97025). However, with this method, it is difficult to deposit metal tungsten selectively in the first place, and even if it can be formed, the accuracy of the opening pattern cannot be avoided, and it is not practical.

As another method, a large amount of boron is implanted on the surface of a silicon substrate to form a boron injection layer, a tungsten layer (metal conductive layer) is formed on the boron injection layer, and the tungsten layer is formed on the tungsten layer. We propose a method to manufacture a transfer mask by performing trench processing on the boron injection layer and the tungsten layer by dry etching using the resist pattern as a mask, and then dissolving and removing the silicon substrate from the back side by wet etching using an alkaline solution. (JP-A-4-188645). However, according to this method, when the silicon substrate is wet-etched with the alkaline solution, the high-concentration boron injection layer is not dissolved or is hardly dissolved in the alkaline solution. As described above, the high-dose boron implantation layer that is not dissolved or is hardly dissolved in the alkaline solution has a very low etching rate in dry etching or is difficult to etch. Therefore, this method cannot avoid a reduction in throughput and is not practical. Furthermore, since a high cost process such as an ion implantation process is required, an increase in manufacturing cost cannot be avoided.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method of manufacturing a transfer mask which can easily and stably manufacture a transfer mask having a highly accurate opening pattern at low cost. .

[0013]

In order to achieve the above object, in the method of manufacturing a transfer mask of the present invention, the back surface of the substrate is etched to form a support frame portion and a thin film portion supported by the support frame portion. In a method for manufacturing a transfer mask, which comprises a step and a step of forming a through hole in the thin film portion, at least:
A step of forming a conductive layer on the substrate surface, and on the conductive layer,
Forming an etching mask layer of the conductive layer, patterning the etching mask layer formed on the conductive layer into a desired shape using a lithographic technique, and using the patterned etching mask layer as a mask And a step of continuously processing the conductive layer and the substrate surface to a predetermined depth by a dry etching technique.

The transfer mask manufacturing method of the present invention is
In the method of manufacturing a transfer mask, preferably, the conductive layer is made of any metal of tungsten, tantalum, molybdenum, and iridium, an alloy containing these metals, or an intermetallic compound of these metals. , The etching mask layer of the conductive layer is SiO ₂
Layer, a Si3N4 layer, a SiC layer, a sialon layer, a SiON layer, or the above-mentioned transfer mask manufacturing method, further comprising forming a wet etching mask layer on the back surface of the substrate. Patterning by lithography technology, and forming a low temperature curable resin layer on the surface and side surfaces of the substrate,
A configuration including a step of curing this and a step of immersing the back surface of the substrate on which the low-temperature curing resin layer is formed in an etching solution to perform wet etching processing on the back surface of the substrate, wherein the low-temperature curing resin has a low temperature of 200 ° C. or lower. A configuration that is a resin that cures at, wherein the low-temperature curing resin is a fluororesin, an ethylene resin, a propylene resin, a silicone resin, a butadiene resin, and a resin containing at least one of a styrene resin, Alternatively, the wet etching mask layer is one of metals selected from the group consisting of tungsten, zirconium, titanium, chromium, nickel and silicon, or an alloy containing these metals, or a combination of these metals or alloys with oxygen, nitrogen and carbon. Of a metal compound containing at least one element of

The present invention will be described in detail below. In the method of manufacturing a transfer mask of the present invention, a plurality of steps are included and the order of these steps can be arbitrarily determined according to the purpose, but for convenience of description, the description will be given according to one of the steps.

FIG. 1 is a process explanatory view showing an example of a manufacturing process of a transfer mask according to the present invention. In the present invention, as shown in FIG. 1, first, the conductive layer 2 is formed on the surface of the substrate 1 (FIG. 1 (a)). Here, as the substrate material, Si, M
o, Al, Au, Cu, etc., but chemical resistance,
From the viewpoint of processing conditions, dimensional accuracy, etc., silicon substrates, SO
It is preferable to use an I substrate or the like.

The conductive layer 2 has an actual density of metal elements of more than 6 g / cc and an electric resistivity of 60 μΩ · cm.
(At 25 ° C), thermal conductivity is 0.04cal
/ Cm / cm ² / sec / ° C., satisfying all of these conditions, having no magnetism, and being dry-etchable, it is preferable to use a conductive material or the like. Specifically, the conductive layer 2 is preferably made of a metal material such as a metal such as tungsten, tantalum, molybdenum, or iridium, an alloy containing these metals, or an intermetallic compound of these metals. this is,
These metal-based materials can be dry-etched, and the linear expansion coefficient of these metal-based materials is closer to the linear expansion coefficient of silicon, which is the transfer mask material, than gold-based elements. This is because it is possible to significantly reduce the positional deviation of the pattern due to thermal distortion or the like during electron beam irradiation.

The conductive layer 2 may be formed by a thin film forming method such as a sputtering method, a vapor deposition method, a CVD method or an electrodeposition method. However, a high quality film level (film denseness, crystal structure, defect-free) is provided. Properties, etc.) are required, and thus it is preferable to use the sputtering method or the CVD method.

The thickness of the conductive layer 2 is appropriately in the range of 0.1 to 3.0 μ. The thickness of the conductive layer 2 is 0.1 μ
If the thickness is thinner, the durability against electron beam becomes poor, and 3.0
If it exceeds μ, it becomes difficult to perform highly accurate dry etching.

Next, a SiO ₂ layer (etching mask layer of the conductive layer) 3 and a SiO ₂ layer 4 are formed on the conductive layer 2 and the back surface of the substrate 1, respectively (FIG. 1B). here,
Although the SiO ₂ layer 3 may be formed only on the conductive layer 2, it may be formed with a well-balanced thickness (for example, 0.5 to 3.0 μ) on both surfaces of the substrate in consideration of the warp of the substrate 1. preferable. Examples of the method for forming the SiO ₂ layer include thin film forming methods such as a sputtering method, a vapor deposition method, a thermal oxidation method, and a CVD method, but in order to avoid deterioration of the conductive layer due to heating such as surface oxidation prevention of the conductive layer, It is preferable to use a thin film forming method such as a room temperature sputtering method or a room temperature CVD method. In addition, SiO
Instead of the _two layers 3, layers such as a Si3N4 layer, a SiC layer, a sialon (composite mixture of Si and Al) layer, and a SiON layer may be formed as an etching mask layer for the conductive layer 2.

Next, the SiO ₂ layer 3 is patterned into a desired shape by using a lithographic technique. Specifically, for example, a resist is applied onto the SiO ₂ layer 3, a resist pattern (not shown) is formed by exposure and development, and the SiO ₂ layer 3 is used as a mask.
Etching is performed to form a resist pattern on the SiO ₂ layer 3
(FIG. 1 (b)). In this case, considering the pattern accuracy, it is preferable that the etching of the SiO ₂ layer 3 is performed by dry etching using a fluorocarbon-based gas as an etching gas.

Next, after removing the resist, dry etching is performed using the patterned SiO ₂ layer 3 as a mask to perform trench etching (etching into a groove shape) on the surfaces of the conductive layer 2 and the substrate 1 to form SiO _2.
The pattern is transferred to them (FIG. 1 (c)).

In this case, the depth of the trench etching on the surface of the substrate 1 is set to a predetermined depth (for example, 5 to 30 μm) so as to form a thin film portion having a predetermined thickness.

The etching gas used for dry etching is not particularly limited. For example, the etching gas for tungsten is CBrF ₃ gas or CF ₄ / O _2.
A mixed gas is Cl as an etching gas for tantalum.
₄ gases are H as etching gas for silicon substrate
Examples thereof include Br gas, Cl ₂ / O ₂ mixed gas, SiCl ₄ / N ₂ mixed gas, and the like. The conductive layer and the silicon substrate may be continuously etched with the same etching gas using SF ₆ gas or the like. As described above, continuous etching with the same etching gas is advantageous in that a high throughput can be obtained without causing a difference in etching anisotropy and isotropicity.

In the present invention, the opening including the conductive layer can be formed by continuous dry etching in one step and in a shorter time than in the conventional case. That is, the process is simplified as compared with the method of forming the metal conductive layer after forming the opening, which is generally performed conventionally, and the opening including the conductive layer is formed in a shorter time than the technique using the boron implantation layer. The formation of parts can be performed. Further, according to the present invention, the opening including the conductive layer can be formed with high accuracy and easily as compared with the conventional case. That is, compared with the method of forming a metal conductive layer after forming an opening, which is generally performed conventionally, the opening including the conductive layer can be made more accurate, and it is easier than the technique using a boron implantation layer. It is possible to form an opening including the conductive layer.

Next, the SiO ₂ layers 3 and 4 which became unnecessary layers
Is removed with a stripping solution (buffered hydrofluoric acid, dilute hydrofluoric acid, etc.), and then a wet etching mask layer 5 is formed on the back surface of the substrate (see FIG.
(D)) This wet etching mask layer 5 is patterned by a lithography technique (FIG. 1).
(E)). However, the SiO ₂ layer 4 can be used as it is as the wet etching mask layer 5 depending on the type of the wet etching solution.
_{The two} layers may be used as they are without being removed.

Here, the wet etching mask layer 5
Is a simple metal such as tungsten, zirconium, titanium, chromium, nickel, or silicon, or an alloy containing these metals, or these metals or alloys and oxygen,
It is preferably composed of a metal compound containing at least one element of nitrogen and carbon. This is because these metal systems can be patterned by low temperature wet etching, and the removal of these metal systems at 100 ° C.
This is because the low temperature wet etching described below can be performed, so that the thin film portion is not damaged during these processes.

The wet etching mask layer 5 may be formed by a thin film forming method such as a sputtering method, a vapor deposition method or a CVD method. If the film quality is poor, the etching solution permeates into the silicon substrate to form a pit (etch pit). In order to avoid this, a high-quality film quality is required, and in order to avoid damage such as cracks due to thermal stress in high temperature film formation, the sputtering method at 350 ° C. or lower Alternatively, the CVD method is preferable.

The thickness of the wet etching mask layer 5 is
A range of 1000 to 10000 angstroms is suitable. If the thickness of the wet etching mask layer 5 is less than 1000 angstroms, the silicon substrate cannot be completely covered. If it exceeds 10,000 angstroms, it takes a long time for film formation and the influence of film stress increases.

The patterning of the wet etching mask layer 5 is specifically, the wet etching mask layer 5
A resist is applied on the resist and a resist pattern (not shown) is formed by a lithography method. The resist pattern is used as a mask to wet-etch the wet etching mask layer 5 with an etching solution for patterning (see FIG. )).

The etching solution used for wet etching is not particularly limited. For example, the titanium etching solution is a 4% dilute fluorinated nitric acid aqueous solution, and the chromium etching solution is dicerium ammonium nitrate / perchloric acid. An aqueous solution and the like, ferric chloride and the like as the nickel etching solution, and a red blood salt (potassium ferricyanide) aqueous solution and the like as the tungsten etching solution can be mentioned.

Next, a low temperature curable resin layer 6 is formed on the front and side surfaces of the substrate, and this is heated or left at room temperature for curing treatment (FIG. 1 (e)). The low temperature curable resin layer 6 plays a role as a protective layer for a portion other than the back surface of the substrate when performing wet etching on the back surface of the substrate.

Here, as the low temperature curable resin, it is preferable to use a resin curable 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 such a low temperature curable 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.

A low temperature curable resin layer 6 is formed on the front and side surfaces of the substrate.
Examples of the method for forming the layer include a spin coating method, a dipping method, a spraying method, and the like. The spin coating method is preferable in consideration of handling, working efficiency, and the like. 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 low temperature curable resin layer 6 has a thickness of 30 to 100.
It is suitable to set it to 0 micron. When the thickness of the low temperature curable resin layer 6 is less than 30 μm, the durability against the etching solution and the function as a protective layer become poor, and when it exceeds 1000 μm, it takes a long time for the curing treatment and the removing treatment.

The low temperature curable resin layer does not affect the other parts due to heat stress during its formation and removal.
It can be easily formed by a spin coating method or the like, has excellent step coverage, and can completely prevent erosion of the etching solution. Therefore, it contributes to manufacturing a transfer mask stably and easily.

Next, the back surface of the substrate having the low temperature curable resin layer 6 formed thereon is dipped in an etching solution to etch the back surface of the substrate (FIG. 1 (f)). Here, examples of the etching solution include alkaline aqueous solutions such as KOH and NaOH, alkaline aqueous solutions containing alcohol and the like, organic alkalis, and the like.

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 method.

In the present invention, since the etching amount (depth) on the back surface of the substrate can be controlled by controlling the etching time, the etching stopper layer (SiO ₂ , boron, etc.) in the SOI substrate etc. is unnecessary, and therefore the bare substrate is not required. Silicon (normal silicon substrate) can be used, which can contribute to cost reduction.

Finally, the low temperature curable resin layer 6 which has become an unnecessary layer is removed with an organic solvent or the like, and the wet etching mask layer 5 is removed with an etching solution or the like to obtain a transfer mask (FIG. 1 (g )). At this time, the removal temperature of these layers is preferably 100 ° C. or lower, more preferably room temperature, in order to avoid the influence of heat stress.

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. The feature is that it can be done, and it has high flexibility.

[0043]

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

Embodiment 1 FIG. 2 is a process explanatory view showing an example of a manufacturing process of a transfer mask according to the present invention. As shown in FIG. 2, first, a tungsten layer 12 having a thickness of 1 μ is formed on a silicon substrate 11 by a sputtering method (FIG. 1A), and further, a sputtering method is performed on the tungsten layer 12 and the back surface of the silicon substrate 11. Thus, SiO ₂ layers 13 and 14 having a thickness of 2 μm were formed.

Next, a resist is applied on the SiO ₂ layer 13 to form a resist pattern (not shown) by a lithography method, and the SiO ₂ layer 13 is etched by dry etching using this resist pattern as a mask to form the resist pattern. It was transferred to the SiO ₂ layer 3 (FIG. 2 (b)).

After removing the resist, the tungsten layer 12 and the surface of the silicon substrate 11 were trench-etched by dry etching using the patterned SiO ₂ layer 13 as a mask, and the SiO ₂ pattern was transferred to them (FIG. 2 (c). )). The tungsten layer 12
CBrF ₃ was used as the etching gas for H ₂ and HBr was used as the etching gas for the surface of the silicon substrate 11.

Next, after removing the SiO2 layers 13 and 14 with buffered hydrofluoric acid, a thickness of 3 is formed on the back surface of the substrate 11 by room temperature sputtering.
A metal titanium layer 15 having a thickness of 000 angstrom was formed (FIG. 2 (d)).

A resist is applied on the metal titanium layer 15 to form a resist pattern (not shown) by a lithography method, and this resist pattern is used as a mask.
The titanium metal layer 15 was wet-etched with a dilute aqueous solution of fluorinated nitric acid to pattern the titanium metal layer 15 (FIG. 2E).

Next, a fluororesin is applied to the front and side surfaces of the substrate to form a fluororesin layer 16, which is heated at 150 ° C. to cure the fluororesin layer 16 (FIG. 2).
(E)).

This substrate was immersed in a KOH aqueous solution heated to 100 ° C. to etch the back surface of the silicon substrate 11 (FIG. 2 (f)).

Finally, the fluororesin layer 16 was removed with an organic solvent, and the titanium metal layer 15 was removed with a 4% dilute aqueous solution of fluorinated nitric acid to obtain a transfer mask (FIG. 2 (g)).

Embodiment 2 FIG. 3 is a process explanatory view showing an example of a manufacturing process of a transfer mask according to the present invention. As shown in FIG. 3, first, a tantalum layer 32 having a thickness of 1 μ is formed on an SOI substrate 31 by a sputtering method.
Was formed (FIG. 3A), and a chromium nitride layer 35 having a thickness of 3000 angstrom was formed on the back surface of the SOI substrate 31 by the room temperature sputtering method (FIG. 3B).

A resist is applied on the chromium nitride layer 35 and a resist pattern (not shown) is formed by a lithographic method. Using this resist pattern as a mask, cerium nitrate / ammonium nitrate / perchloric acid aqueous solution is used to form chromium nitride. Layer 35 was wet etched to pattern chromium nitride layer 35 (FIG. 3 (b)).

Next, an ethylene-propylene resin is applied to the surface and side surfaces of the substrate to a thickness of 300 μm to form an ethylene-propylene resin layer 36, and the coating is heated at 90 ° C. to carry out a curing treatment (FIG. 3). (C)).

This substrate was dipped in an aqueous KOH solution containing 10% of IPA (isopropyl alcohol) heated to 70 ° C.,
The back surface of the SOI substrate 31 was etched to form a thin film portion (FIG. 3D).

Next, the ethylene-propylene resin layer 3
6 was removed with an organic solvent, and the metal chromium layer 35 was removed with the same aqueous solution of cerium ammonium nitrate / perchloric acid as described above (FIG. 3 (e)).

Next, a 1.8 μ thick SiO 2 layer 33 was formed on the tantalum layer 32 by the CVD method. Then S
A resist is applied on the iO ₂ layer 33, a resist pattern (not shown) is formed by a lithography method, and the SiO ₂ layer 33 is etched by dry etching using this resist pattern as a mask to form the resist pattern on the SiO ₂ layer 33. It was transferred (FIG. 3 (e)).

After removing the resist, the surface of the tantalum layer 32 and the surface of the SOI substrate 31 are trench-etched by dry etching using the patterned SiO ₂ layer 33 as a mask to form openings (transmission holes) (see FIG. f)). Cl ₂ was used as the etching gas for the tantalum layer 32, and a Cl ₂ / SF ₆ / SiCl ₄ mixed gas was used as the etching gas for the surface of the SOI substrate 31.

Finally, the SiO ₂ layer 33 and the intermediate SiO ₂
The layer was removed with buffered hydrofluoric acid to obtain a transfer mask (Fig. 3
(G)).

Embodiment 3 FIG. 4 is a process explanatory view showing an example of a manufacturing process of a transfer mask according to the present invention. As shown in FIG. 4, first, a tungsten layer 42 having a thickness of 1 μ is formed on the SOI substrate 41 by a sputtering method (FIG. 4A), and further, the SOI substrate 41 is formed.
A 2000 angstrom thick nickel layer 45 was formed on the back surface by room temperature sputtering (FIG. 4B).

A resist pattern (not shown) is formed on the nickel layer 45 by a lithography method to form a resist pattern, and the nickel layer 45 is wet-etched with a ferric chloride solution using the resist pattern as a mask. The nickel layer 45 was patterned (Fig. 4
(B)).

Then, on the tungsten layer 42, a photosensitive SOG (spin-coated layer) having a thickness of 2.0 μ is formed by spin coating.
The on-glass layer 43 is formed, and this photosensitive SOG layer 43 is formed.
Was patterned by electron beam lithography and then baked at 200 ° C. to obtain a patterned SiO ₂ layer 43 (FIG. 4C).

Subsequently, the surface of the tungsten layer 42 and the surface of the SOI substrate 41 were trench-etched by dry etching using the patterned SiO ₂ layer 43 as a mask, and the SiO ₂ pattern was transferred to them (FIG. 1).
(D)). As the etching gas for the tungsten layer 42 and the etching gas for the silicon layer on the surface of the SOI substrate 41, the same Cl ₂ / SF ₆ mixed gas was used for continuous etching.

Next, silicon resin is applied to the front and side surfaces of the substrate to a thickness of 200 μm to form a silicon resin layer 46, which is heated at 100 ° C. to cure the silicon resin layer 46 (FIG. 4). (E)).

90% of this substrate was formed by using the silicon resin layer 46 as a protective layer and the nickel layer 45 as an etching mask layer.
The SOI substrate 41 is dipped in a NaOH aqueous solution heated to ℃.
The back surface was etched to form a thin film (Fig. 4).
(F)).

Finally, the silicon resin layer 46 is removed with an organic solvent, the nickel layer 45 is removed with a ferric chloride solution, and S
The iO ₂ layer 43 and the intermediate SiO ₂ layer were removed with buffered hydrofluoric acid to obtain a transfer mask (FIG. 4 (g)).

In the above Examples 1 to 3, it was confirmed that the low temperature curable resin layer can completely prevent the etching solution from being corroded during the wet etching of the back surface of the substrate. Further, it was confirmed that the influence of heat stress can be avoided through all the steps, and it was confirmed that the transfer mask can be stably manufactured without any damage or the like in the middle of the steps.

Although the present invention has been described above with reference to the preferred embodiments, the present invention is not necessarily limited to the above embodiments. For example, similar results were obtained when zirconium, tungsten, or the like was used as the wet etching mask layer. Similar results were obtained by using a butadiene resin, a styrene resin, or a mixed resin including the resins used in the examples as the low temperature curable resin.
Further, the manufacturing method of the transfer mask of the present invention can be used not only for the electron beam exposure mask but also for the ion beam exposure mask and the like.

[0069]

As described above, according to the method of manufacturing a transfer mask of the present invention, the opening including the conductive layer is formed.
The continuous dry etching can be performed in one step and in a short time, and can be performed with high accuracy and easily.

Further, by adopting a low temperature curing resin layer and a wet etching mask layer which can be formed and removed at a low temperature, it is possible to avoid the influence of thermal stress, and to adopt a large number of wet etching processes to simplify the process and Cost reduction can be achieved.

Furthermore, the low temperature curable resin layer can be easily formed, has excellent step coverage and can completely prevent the etching solution from being eroded.

Further, in the present invention, the etching stopper layer of the substrate is unnecessary, and bare silicon can be used.

As described above, according to the present invention, a transfer mask having a highly accurate opening pattern can be manufactured easily and stably at low cost.

[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.

FIG. 4 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 Conductive Layer 3 SiO ₂ Layer 4 SiO ₂ Layer 5 Wet Etching Mask Layer 6 Low Temperature Curing Resin Layer

Claims (7)

[Claims] 1. A method of manufacturing a transfer mask, comprising: a step of etching a back surface of a substrate to form a support frame portion and a thin film portion supported by the support frame portion; and a step of forming a through hole in the thin film portion. In at least a step of forming a conductive layer on the surface of the substrate, a step of forming an etching mask layer of the conductive layer on the conductive layer, and a step of forming the etching mask layer formed on the conductive layer using a lithography technique. A step of patterning into a desired shape, and a step of continuously processing the conductive layer and the substrate surface to a predetermined depth by a dry etching technique using the patterned etching mask layer as a mask. And a method for manufacturing a transfer mask. 2. The conductive layer comprises a metal selected from the group consisting of tungsten, tantalum, molybdenum and iridium,
2. The method of manufacturing a transfer mask according to claim 1, wherein the transfer mask is made of an alloy containing these metals or an intermetallic compound of these metals. 3. The etching mask layer of the conductive layer is S
iO ₂ layer, Si 3 N 4 layer, SiC layer, sialon layer, Si
The method of manufacturing a transfer mask according to claim 1, wherein the transfer mask is any one of the ON layers. 4. The method of manufacturing a transfer mask according to claim 1, further comprising a step of forming a wet etching mask layer on the back surface of the substrate and patterning the wet etching mask layer by a lithography technique, and a surface of the substrate. And a step of forming a low temperature curable resin layer on the side surface and curing the same, and a step of immersing the back surface of the substrate on which the low temperature curable resin layer is formed in an etching solution to perform wet etching processing on the back surface of the substrate. The method of manufacturing a transfer mask according to claim 1, wherein the transfer mask is manufactured. 5. The method of manufacturing a transfer mask according to claim 4, wherein the low temperature curable resin is a resin which is cured at a low temperature of 200 ° C. or lower. 6. The low temperature curable resin is made of 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. The method for manufacturing a transfer mask according to claim 4. 7. The wet etching mask layer comprises a metal selected from the group consisting of tungsten, zirconium, titanium, chromium, nickel and silicon, or an alloy containing these metals, or a combination of these metals or alloys with oxygen and nitrogen, The method for manufacturing a transfer mask according to claim 4, wherein the transfer mask is made of a metal compound containing at least one element of carbon.