JPH1088385A - Plating method of tungsten alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain plating coating contg. W, low in stress and excellent in a secular change in the case of use and process stability, surface conditions and precision by precipitating an alloy of Ni, Fe or Co with W on the surface of a plating base electrode formed on the surface of the material to be plated by an electrolytic plating method. SOLUTION: A plating base electrode is formed on the surface of the material to be plated, thereafter, the surface of the base electrode is provided with a pattern of nonconducting substance having an opening with a prescribed shape, and after that, any coating of an alloy of W and Ni, W and Fe or W and Co is precipitated by an electrolytic method to form plating coating having a uniform compsn. contg. W only in the opening, having high density and excellent in precision. This alloy plating coating is the one composed of a low crystalline alloy, having a low thermal expansion coefficient, high in hardness, excellent in wear resistance, furthermore having resistance to acid such as concentrated nitric acid and alkali and stable. Thus, a mask for X-ray lithograpy and a mold for molding high in X-ray absorptivity, low in stress and excellent in a secular change in the case of use and process stability, surface conditions and precision can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a fine structure by electrolytic plating, and more particularly to a mask for X-ray lithography and a method for producing the same, and a mold for molding and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, tungsten (W) metal has attracted attention as a structural material because of its chemical stability, high hardness, low thermal expansion coefficient, and high melting point. However, it is expensive and difficult to machine, so it is not used enough. Investigations have been made as a surface treatment material for the plating method in order to utilize the properties of tungsten, but the formation of a W-only metal film by a wet process (plating method) has not been successful. The only successful example is the co-deposition with other metals. As a typical example, eutectoid with nickel is known.

On the other hand, a method of processing the surface of a material by using a lithography technique is widely used in industry, particularly in the field of electronics industry. According to this method, a large number of products having the same pattern can be manufactured.

When the irradiation energy is visible light or ultraviolet light, a mask provided with a black opaque pattern such as silver or chrome on a transparent substrate such as glass or quartz is used.

However, in recent years, as finer pattern formation is required and lithography processing is required in a shorter time, particle beams such as electron beams, ion beams, and X-rays are attracting attention as irradiation energy beams. Became.
When these electron beams, ion beams, X-rays, and the like are used as energy rays, a glass or quartz plate that has been used as a mask substrate member in the case of conventional visible light or ultraviolet light passes these energy rays. Therefore, it is not suitable as a substrate material for a mask.

[0006] For example, in lithography using X-rays, various inorganic thin films such as ceramic thin films such as silicon, ticker silicon and silicon carbide; organic polymer thin films such as polyimide, polyamide and polyester; And the like are used as an energy ray transmitting body, and a pattern in which a metal such as gold, platinum, or tungsten is formed on the energy ray transmitting body as an energy ray absorbing body is used as a mask. Since this mask has no self-retaining property, it is supported by an appropriate holder.
An annular holding substrate is generally used as the holding body. That is,
A mask structure is formed by adhering and fixing the peripheral portion of the energy ray transmitting body thin film having the energy ray absorbing body pattern formed on one side to one end face of the annular holding substrate.

In order to perform lithography using such a mask structure, conventionally, a so-called tube X-ray in which an X-ray is generated by applying an electron beam to a metal target such as palladium or rhodium as an X-ray source. Although the source is the mainstream, in recent years, so-called SR (synchrotron radiation) lithography using radiation emitted from a synchrotron has been attracting attention. According to this, since parallel energy rays can be obtained, LIGA (Lithog
raphie Galvanoformung Abformung) process can be realized. This means that one of the key technologies for realizing micromachines will be solved.

However, when SR lithography is to be adopted, the wavelength of X-rays is changed from 4 ° in the related art (a system using a tube target as an X-ray source) to 10 °, the irradiation intensity is increased by two digits or more, and heat is generated. And other problems that have not been considered before have arisen. On the other hand, further fine processing is required, and there is an expectation that the line width of transfer is from 0.8 μm to 0.2 μm or less.

Various countermeasures have been considered to address these problems. As the energy ray transmitting body, for example, an inorganic film such as Si, SiN, or SiC having better thermal conductivity and a smaller coefficient of thermal expansion than an organic film such as polyimide is used.
A thin film having a thickness of about 8 μm to 2 μm has come to be used. Similarly, as for the X-ray absorber, a low coefficient of thermal expansion, a material having a low stress, a process stability, and the like are required.

[0010] Gold (Au) plating has been mainly used to initially produce a mask pattern for X-ray lithography. However, in recent years, contamination of a semiconductor manufacturing process has become a problem. It has been replaced by a method of processing heavy metals by a RIE (reactive ion etching) dry process.

In related academic societies, literatures, etc., Ta, as a promising material to be adopted as an X-ray absorber in the future,
W, two metals. However, when these metal materials are used as an X-ray absorber, the surface is roughened due to abnormal crystal growth during film formation, because a film formation method by a reduced pressure sputtering method using a single metal target is conventionally used. Problems such as deterioration of planarity and increase of positional distortion due to internal stress occurred, and a highly accurate mask could not be manufactured.

Attempts to solve these problems include a method of nitriding W to form WN, and a method of alloying W-
A method using Ti, W-Ta, a method using Ta-B, and the like have been proposed, but have not been sufficient.

[0013]

SUMMARY OF THE INVENTION The present invention provides a low stress,
An object of the present invention is to provide a method for forming a plated film of an alloy containing tungsten, which is excellent in aging and process stability during use, and is excellent in surface condition and accuracy.

Further, the present invention provides a mask for X-ray lithography, which has high X-ray absorption, low stress, excellent aging during use and process stability, and also has excellent surface condition and precision, and a method of manufacturing the same. That is the purpose.

A further object of the present invention is to provide a mold for molding which is excellent in heat resistance, low stress, change over time during use and process stability, and is excellent in surface condition and precision, and a method for producing the same. .

[0016]

Means for Solving the Problems The present inventor has conducted intensive studies from a viewpoint different from the prior art and found that these problems can be solved by forming an alloy containing tungsten by plating. Invented the invention.

That is, according to the present invention, there is provided a step of forming a plating base electrode on a surface of a material to be plated, and forming an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt on the plating base electrode by electrolytic plating. The present invention relates to an electrolytic plating method including a step of precipitating one of alloys.

According to the plating method of the present invention, an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt are formed by electrolytic plating, so that a high-density and uniform composition containing tungsten can be obtained. A highly accurate plating film can be formed. This alloy plating film is a low crystallinity alloy with good surface properties, low coefficient of thermal expansion, low internal stress, high hardness and excellent wear resistance. Is excellent. Furthermore, it is resistant and stable to acids and alkalis such as concentrated nitric acid.

In the plating method of the present invention, after forming a plating base electrode, a pattern of a non-conductive substance having a predetermined shape opening is provided on the plating base electrode, and then electrolytic plating is performed. Only alloys containing tungsten can be precipitated.

When a pattern is formed by using a resist material such as a photoresist or an electron beam resist as a non-conductive substance, an expensive vacuum processing apparatus such as RIE is not required, and the precision is excellent at a low temperature by adopting a wet process. Since an alloy film containing tungsten can be formed, manufacturing cost can be significantly reduced.

Further, the present invention relates to a mask for X-ray lithography having an alloy film of any one of an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt as an X-ray absorber.

This mask for X-ray lithography was first obtained by forming the above-mentioned alloy film containing tungsten as an X-ray absorber by using the above-mentioned plating method on an X-ray transmitting body. An X-ray lithography mask excellent in X-ray absorption, low stress, change over time during use and process stability, as well as excellent surface condition and accuracy. In the plating method of the present invention, a mask containing no contaminated metal can be easily manufactured by using a plating solution containing no metal that causes contamination of a semiconductor device. Therefore, when this mask for X-ray lithography is used in the manufacture of a semiconductor device or the like, an accurate pattern can be formed, and the semiconductor device is not contaminated. Can be manufactured.

Further, the present invention relates to a molding die having an alloy film of any one of an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt on the surface of the die.

This mold for molding is obtained by applying the above-mentioned plating method to the surface of the matrix, and has heat resistance,
It is a mold for molding that is low in stress, excellent in aging during use and process stability, and excellent in surface condition and accuracy. This mold is made of glass, plastic,
When used for molding of metal or the like, a molded product having a good surface condition can be obtained.

The plating method of the present invention can be used for manufacturing not only the mask for X-ray lithography and the mold for molding but also a structure processed and formed by another plating method (electroforming method).

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an aqueous solution containing (a) a tungsten compound, (b) any one of nickel, iron and cobalt, (c) an organic acid, and (d) ammonia is used as a plating solution.

As the tungsten compound, a water-soluble salt is preferable, and examples thereof include sodium tungstate, potassium tungstate, ammonium tungstate, and magnesium tungstate. Among them, sodium tungstate and potassium tungstate are preferred.

The content of the tungsten compound is 100 parts of water.
Parts (parts by weight, the same applies hereinafter) is about 1 to 10 parts, preferably about 4 to 6 parts.

As the compound of nickel, iron or cobalt, a water-soluble salt is preferable, and examples thereof include nickel sulfate, nickel sulfamate, iron sulfate, iron chloride, cobalt sulfate and cobalt chloride. Of these, sulfates (including hydrates) are preferred.

The content of the nickel, iron or cobalt compound is about 0.2 to 4 parts, preferably about 1 to 2 parts, per 100 parts of water. As for the ratio to the tungsten compound in the plating solution, the molar ratio of W: Ni (or Fe, Co) to the tungsten compound was 1: 1:
(0.05-0.5), preferably 1: (0.1-
0.3).

As the organic acid, a compound having both a -COOH group and a -OH group is preferable. Examples thereof include malic acid, lactic acid, citric acid, gluconic acid, salicylic acid, gallic acid, tartaric acid and the like, and mixtures thereof. it can. Among them, malic acid, lactic acid, citric acid, tartaric acid, and a mixture thereof are preferable. Further, it is most preferable to use a mixture of malic acid and lactic acid, since the mixture is left at room temperature for about 2 weeks without deposits and the like, and has very good storage stability. In this case, the ratio of malic acid to lactic acid is 5: 1 to 1:
It is about 1.

The content of the organic acid is based on 100 parts of water.
It is about 2 to 10 parts, preferably about 4 to 8 parts.

The content of ammonia is about 1 to 10 parts, preferably about 2 to 6 parts, per 100 parts of water, as the content of the aqueous solution of ammonia (28%).

The plating solution may further have a pH value if necessary.
It may contain additives used in ordinary plating solutions such as a regulator, a pH buffer, a surfactant, and a pit inhibitor.

The plating conditions of the present invention are appropriately selected according to a conventional method.
The processing temperature can be about 30 to 90 ° C.,
pH is about 4 to 10 and current density is 0.1 to 100 mA /
cm ^TwoThe degree is preferred.

Since the plating solution of the present invention can employ neutral conditions, even when a pattern-shaped alloy plating film is formed, it is not necessary to use a special resist. A developable resist can be used.

By using such plating solutions and conditions, 1 to 60 wt% of tungsten, nickel,
An alloy film containing 99 to 40 wt% of iron or cobalt can be obtained. The tungsten content in the alloy film is p
It can be adjusted by changing H, liquid temperature, amount of ammonia, kind and amount of acid.

The underlying electrode used at this time can be used as long as it is electrically conductive. Tungsten alone and an alloy of tungsten are preferable, and in particular, adhesion, film stress (strain), surface properties (surface roughness) are preferable. From the viewpoint of (1), an alloy of tungsten with any of molybdenum, titanium, cobalt, nickel, tin, and iron is preferable.

The base electrode may be formed on the surface of the material to be plated on which the alloy film is to be formed, by a vapor deposition method, a sputtering method, or the like, to such a thickness as to have conductivity as an electrode. X is too thick
Usually, 0.01-0.2
It is about μm.

In the mask for X-ray lithography of the present invention, a base electrode is formed on an X-ray transmitting body having a thickness and a material which practically transmits X-rays, so as to have a thickness which allows practical transmission of X-rays. After that, it can be manufactured by forming an alloy film containing tungsten in a predetermined pattern in the same manner as described above. This X-ray transmitting body includes Si, SiN, Si
A ceramic thin film such as C or an organic polymer thin film such as polyimide, polyamide, or polyester can be used. However, a ceramic thin film of Si, SiN, SiC or the like is preferable in order to exhibit the effects of the present invention such as heat resistance and high precision.

This X-ray transmitting body is used in terms of handling and the like.
It is preferable to be held by an appropriate holder (a member having a large mechanical strength). If an X-ray transmitting body is formed on the surface of, for example, a silicon substrate as a support, the X-ray transmitting body can be exposed by etching from the opposite side after the plating film is formed. In this case, as the X-ray transmitting body, for example, a SiC film, a SiN film, or the like can be used.

To form the alloy film in a predetermined pattern,
It can be performed by using a resist material such as a photoresist or an electron beam resist on the base electrode, exposing and developing, providing an opening pattern of a predetermined shape, performing plating, and depositing an alloy film only in the opening portion.

In order to manufacture the mold for molding of the present invention, first, a base electrode is formed on the surface of the mold material by the same method as described above. In this case, unlike the case of the X-ray lithography mask, there is no problem even if the thickness is large, but it is not particularly necessary to do so.

Next, an alloy film containing tungsten can be formed on the surface by plating the base electrode in the same manner as described above.

[0045]

Next, the present invention will be described more specifically with reference to examples.

[Manufacture of X-ray lithography mask] [Example 1] (W-Ni X-ray mask) As a mask holder, Si having a diameter of 3 inches and a thickness of 2 mm was used.
Using a substrate 2, an SiC film 1 as an X-ray transmitting body was provided with a thickness of 2 μm on both the front side and the back side by a CVD film forming method. In order to use as a mask for Si back etching, a window 4 of 20 × 20 mm was provided in the backside SiC film.

On the front side of this substrate, a W electrode film 3 was formed to a thickness of 0.05 μm as a base electrode by sputter deposition [FIG. 1]. As a film forming apparatus, a sputter deposition apparatus was used. The purity of W is 99.99 for the sputter target.
% Was used.

An i-line resist 5 was applied to the substrate on which the W electrode film 3 was provided by a thickness of 0.8 μm by spin coating. After performing a predetermined pre-paking, a pattern having a line width of 0.35 μm was printed using an i-line stepper (Canon FPA-3000-i4). After performing the developing process and the rinsing process, post-baking was performed to form a resist pattern.

Next, the surface of the mask substrate was set toward the anode using a jet-type plating apparatus [a mask substrate on the cathode (upper) and a platinum mesh electrode on the anode (lower)], and the current density was 2 A / dm ² . After plating for 5 minutes, the W-Ni alloy film 6
Was formed [FIG. 2]. At this time, as a plating solution, a mixture of 100 parts of water, 6 parts of sodium tungstate, 1 part of nickel sulfate, 4 parts of malic acid, 2 parts of lactic acid and 4 parts of ammonia was used, and the pH was adjusted to 7.0. The temperature is 65 ° C.

After the plated substrate was treated with a special remover solution to remove the resist, the thickness of the plating pattern was measured to be 0.6 μm. Observation of the surface with a scanning electron microscope (SEM) revealed a plating pattern having a line width of 0.35 μm with extremely small surface irregularities and vertical wall surfaces [FIG. 3].

When the plating pattern was analyzed, it was confirmed that the alloy was a 42:58 wt% W: Ni ratio.

Next, back etching of the back surface of the Si substrate was performed. K is added to the window portion of the SiC film that has been provided in advance.
Etching was performed using a 30 wt% OH solution at 110 ° C. The surface was completely shielded so that the etching solution did not act on the absorber pattern portion on the surface. 2
It took about 6 hours to etch the Si substrate having a thickness of mm. Finally, a donut-shaped frame plate 7 having a diameter of 4 inches and a thickness of 8 mm is bonded using an epoxy adhesive 8.
An X-ray lithography mask was prepared (FIG. 4).

In the following Examples 2 to 22, the mask for X-ray lithography was obtained by repeating Example 1 except that the film of the X-ray transmitting body, the plating base electrode and the plating solution were as follows. Was manufactured. Each of the patterns of the plated alloy film had very small irregularities on the surface, the wall surfaces were vertical, and the pattern line width was 0.35 μm with high accuracy.

Example 2 (W-Ni X-ray mask) X-ray transmitting film: CVD-SiN film 2 μm Plating base electrode: W-Mo (95: 5 wt%) sputter-deposited film 0.04 μm thick Plating solution: W-Ni plating solution; 6 parts of sodium tungstate, 1 part of nickel sulfate, 3 parts of malic acid, 3 parts of lactic acid,
100 parts of water, 4 parts of ammonia, pH 7.5, liquid temperature is 62
℃ Analysis result of plated alloy: W: Ni = 44: 56w
t%

Example 3 (X-ray mask of W-Ni) X-ray transmitting film: CVD-SiN film 2 μm Plating base electrode: W-Mo (95: 5 wt%) sputter-deposited film 0.04 μm Thick plating solution: W-Ni plating solution; 4 parts of ammonium tungstate, 2 parts of nickel sulfate, 2 parts of malic acid, 4 parts of lactic acid
Parts, water 100 parts, ammonia 2 parts, pH 7.2, liquid temperature is 60 ° C Analysis result of plated alloy: W: Ni = 40: 60w
t%

Example 4 (X-ray mask of W-Ni) X-ray transmitting film: CVD-SiC film 2 μm Plating base electrode: Ni sputter deposited film 0.05 μm
Thick plating solution: W-Ni plating solution; 6 parts of sodium tungstate, 2 parts of nickel sulfate, 6 parts of citric acid, 100 parts of water
Part, ammonia 3 part, pH7, liquid temperature is 60 ° C Analysis result of plated alloy: W: Ni = 41: 59w
t%

Example 5 (W-Ni X-ray mask) X-ray transparent film: CVD-SiN film 2 μm Plating base electrode: W sputter-deposited film 0.02 μm thick Plating solution: W-Ni plating solution 6 parts of sodium tungstate, 2 parts of nickel sulfate, 6 parts of tartaric acid, 100 parts of water,
3 parts of ammonia, pH9, liquid temperature is 65 ° C Analysis result of plated alloy: W: Ni = 40: 60w
t%

[Example 6] (X-ray mask of W-Ni) Gluconic acid was used as the plating solution instead of citric acid in the plating solution of Example 4, but the surface condition was also good and the precision was high. X-ray lithography masks could be manufactured.

[Example 7] (X-ray mask of W-Ni) Lactic acid, malic acid, and a mixture thereof were used in place of citric acid in the plating solution of Example 4 as a plating solution. A highly accurate mask for X-ray lithography having a good surface condition could be manufactured.

[Example 8] (X-ray mask of W-Fe) X-ray transmitting film: CVD-SiC film 2 µm Plating base electrode: Sputter deposited film of W 0.04 µm thick Plating solution: W-Fe plating solution Analysis results of 100 parts of water, 6 parts of sodium tungstate, 1 part of iron sulfate, 4 parts of malic acid, 2 parts of lactic acid, 8 parts of ammonia, pH 8.5, and a liquid temperature of 65 ° C. plated alloy: W: Fe = 42: 58 wt %

Example 9 (X-ray mask of W—Fe) X-ray transmitting film: CVD-SiN film 2 μm Plating base electrode: W—Mo (95: 5 wt%) sputter-deposited film 0.04 μm thick Plating solution: W-Fe plating solution; 6 parts of sodium tungstate, 2 parts of iron sulfate, 3 parts of malic acid, 3 parts of lactic acid, 10 parts of water
0 parts, ammonia 6 parts, pH 8.2, liquid temperature is 62 ° C. Analysis result of plating alloy: W: Fe = 42: 58 wt%

Example 10 (W-Fe X-ray mask) X-ray transmitting film: CVD-SiC film 2 μm Plating base electrode: Ni sputter deposited film 0.05 μm
Thick plating solution: W-Fe plating solution; 100 parts of water, 6 parts of sodium tungstate, 2 parts of iron sulfate, 6 parts of citric acid, 7 parts of ammonia, pH 8.8, liquid temperature of 62 ° C Analysis result of plating alloy: W: Fe = 38: 62wt%

[Example 11] (X-ray mask of W-Fe) X-ray transparent film: CVD-SiN film 2 µm Plating base electrode: Sputter deposited film of W 0.02 µm thick Plating solution: W-Fe plating solution 100 parts of water, 6 parts of sodium tungstate, 2 parts of iron sulfate, 6 parts of tartaric acid, 8 parts of ammonia, pH 9, solution temperature 65 ° C Analysis result of plating alloy: W: Fe = 42: 58wt%

[Example 12] (X-ray mask of W-Fe) Gluconic acid was used as the plating solution instead of citric acid in the plating solution of Example 10, but the surface condition was also good and the accuracy was high. X-ray lithography masks could be manufactured.

[Example 13] (X-ray mask of W-Fe) Lactic acid, malic acid, and a mixture thereof were used in place of citric acid in the plating solution of Example 10 as a plating solution. A highly accurate mask for X-ray lithography having a good surface condition could be manufactured.

[Example 14] (X-ray mask of W-Co) X-ray transmitting film: CVD-SiC film 2 µm Plating base electrode: Sputter deposited film of W 0.05 µm thick Plating solution: W-Co plating solution Water 100 parts, sodium tungstate 6 parts, cobalt sulfate 2 parts, malic acid 4
Parts, lactic acid 2 parts, ammonia 3 parts, pH 7, solution temperature 65 ° C Analysis result of plating alloy: W: Co = 41: 59wt%

Example 15 (X-ray mask of W—Co) X-ray transmitting film: CVD-SiN film 2 μm Plating base electrode: sputter-deposited film of W—Mo (95: 5 wt%) 0.04 μm thick Plating solution: W-Co plating solution; 6 parts of sodium tungstate, 1 part of cobalt sulfate, 3 parts of malic acid, 3 parts of lactic acid,
100 parts of water, 4 parts of ammonia, pH 7.5, liquid temperature of 62 ° C. Analysis result of plating alloy: W: Co = 40: 60 wt%

Example 16 (X-ray mask of W—Co) X-ray transmitting film: CVD-SiC film 2 μm Plating base electrode: Ni sputter deposited film 0.05 μm
Thick plating solution: W-Co plating solution; water 100 parts, sodium tungstate 6 parts, cobalt sulfate 2 parts, citric acid 6
Part, ammonia 4 part, pH9, liquid temperature 60 ° C Analysis result of plating alloy: W: Co = 41: 59wt%

Example 17 (X-ray mask of W—Co) X-ray transmitting film: CVD-SiN film 2 μm Plating base electrode: sputter deposited film of W 0.02 μm thick Plating solution: W—Co plating solution 100 parts of water, 6 parts of sodium tungstate, 2 parts of cobalt sulfate, 6 parts of tartaric acid,
4 parts of ammonia, pH9, solution temperature 65 ° C Analysis result of plating alloy: W: Co = 40: 60wt%

[Example 18] (X-ray mask of W-Co) Gluconic acid was used as a plating solution instead of citric acid in the plating solution of Example 16, but the surface condition was also good and the accuracy was high. X-ray lithography masks could be manufactured.

[Example 19] (X-ray mask of W-Co) Lactic acid, malic acid, and a mixture thereof were used in place of citric acid in the plating solution of Example 16 as a plating solution. A highly accurate mask for X-ray lithography having a good surface condition could be manufactured.

[Embodiment 20] (X-ray mask) In the above embodiment, W, W-Mo or Ni was used as the base electrode. In this embodiment, however, W is as follows.
And an alloy of Ti. As a result, a highly accurate mask for X-ray lithography having a similarly good surface condition could be manufactured. X-ray transmitting film: CVD-SiC film 2 μm Plating base electrode: Sputter deposited film of W—Ti (99: 1 wt%) 0.05 μm thick Plating solution: W—Fe plating solution; 100 parts of water, sodium tungstate 6 Parts, iron sulfate 2 parts, gluconic acid 6 parts, ammonia 3 parts, pH 7, liquid temperature 60 ° C

[Example 21] (X-ray mask) An alloy of W and Co was used as a base electrode as follows. Similarly, a mask for X-ray lithography having a good surface condition and high accuracy can be manufactured. did it. X-ray transmitting film: CVD-SiC film 2 μm Plating base electrode: W-Co (90:10 wt%) sputter-deposited film 0.04 μm thick Plating solution: W-Co plating solution; 100 parts of water, sodium tungstate 6 Parts, cobalt sulfate 2 parts, malic acid 4
Parts, lactic acid 2 parts, ammonia 3 parts, pH 7, liquid temperature 60 ° C

[Example 22] (X-ray mask) As in the other examples, a sputter-deposited film of an alloy of W and Ta, an alloy of W and Fe, and an alloy of W and Sn was used as a base electrode for plating. The masks for X-ray lithography were manufactured in the same manner as described above. As a result, similarly, those having good surface conditions and high precision were obtained.

Example 23 (Mold Mold) On a surface of a glass mold, a 0.05 μm W thin film was formed as a base electrode by sputter deposition. This surface is coated with W using the same plating solution and conditions as in Example 1.
A plated film of a Ni alloy was formed.

When a glass lens was manufactured using this mold, the glass lens was sufficiently resistant to a temperature close to 1000 ° C. and showed good mold release from the glass lens material.

[Example 24] (Mold forming mold) W-type light was formed on the surface of the master of the diffraction grating in the same manner as in Example 23.
A Ni alloy plating film was formed.

This matrix showed good mold separation from the glass material, and a high-quality diffraction grating could be produced.

Example 25 (Mold Mold) A W-Ni alloy plating film was formed on the surface of a plastic mold under the following conditions. Plating base electrode: W-Mo (95: 5 wt%) sputter-deposited film 0.04 μm thick Plating solution: W-Ni plating solution; 6 parts of sodium tungstate, 1 part of nickel sulfate, 3 parts of malic acid, 3 parts of lactic acid,
100 parts of water, 4 parts of ammonia, pH 7.5, liquid temperature is 62
° C. The mold for the plastic mold sufficiently withstands a temperature close to 300 ° C., showed good mold release with respect to the plastic lens material, and was able to produce a high-precision plastic lens.

Example 26 (Mold Mold) A WF was applied to the surface of a glass mold under the following conditions.
An e-alloy plating film was formed. When a glass lens was manufactured using this mold, the glass lens was sufficiently resistant to a temperature close to 1000 ° C. and showed good mold release from the glass lens material. Plating base electrode: Sputter deposited film of W 0.04 μm thick Plating solution: W-Fe plating solution; 100 parts of water, 6 parts of sodium tungstate, 1 part of iron sulfate, 4 parts of malic acid, 2 parts of lactic acid, 4 parts of ammonia, pH 7.2, liquid temperature 65 ° C. [Example 27] (Mold Mold) On the surface of the master of the diffraction grating, W-
An Fe alloy plating film was formed. This mold showed good mold release with respect to the glass material, and was able to produce a high-quality diffraction grating.

Example 28 (Mold Mold) A plating film of a W—Fe alloy was formed on the surface of a plastic mold under the following conditions. Plating base electrode: W-Mo (95: 5 wt%) sputter-deposited film 0.04 μm thick Plating solution: W-Fe plating solution: 6 parts of sodium tungstate, 2 parts of iron sulfate, 3 parts of malic acid, 3 parts of lactic acid, Water 10
0 parts, ammonia 3 parts, pH7, liquid temperature is 62 ° C. The mold for plastic molds can withstand a temperature close to 300 ° C sufficiently, shows good mold release for plastic lens materials, and uses high precision plastic lenses. Could be created.

[Example 29] (Example 1 of use of X-ray lithography mask) Using the X-ray lithography mask prepared in Examples 1 to 22, the resist was patterned as follows.

First, an X-ray resist (SAL-601 resist manufactured by SHIPLEY) was applied to the surface of the Si wafer with a thickness of 1.2 μm using a spin coater, and prebaked under predetermined conditions.

As shown in FIG. 5, the gap between the resist surface of the Si wafer 16 and the mask 15 was maintained at a gap of 30 μm, and stepping exposure was performed using a synchrotron radiation (SR) light source 11 and an X-ray stepper. Pre-exposure bake (PostExposure Bak)
After performing e), a development process using a dedicated developing and rinsing solution was performed.

As a result, the line width was 0.35 μm and the height was 1.2 μm.
The m-type negative resist pattern could be accurately formed on the Si wafer.

[Example 30] (Example 2 of use of mask for X-ray lithography) Using the mask for X-ray lithography prepared in Examples 1 to 22, a semiconductor device can be manufactured, for example, as follows.

FIG. 6 shows a process of manufacturing a device on a silicon wafer.

In step 1 (oxidation), the surface of the wafer is oxidized. Step 2 (CVD) forms an insulating film on the wafer surface. In step 3, electrodes and the like are formed as necessary. In step 4 (ion implantation), ions are implanted into the wafer. In step 5 (resist processing), an X-ray resist is applied on the wafer. In step 6 (exposure), the circuit pattern of the X-ray mask is printed and exposed on the resist film on the wafer by the X-ray (SR) exposure method as in the twenty-third embodiment. Step 7 (development) develops the resist on the exposed wafer. In this step, PEB (post E
xposure Bake) step. Step 8
In (etching), portions other than the developed resist image are scraped off. In step 9 (resist removal), unnecessary resist after etching is removed. By repeating these steps as necessary, multiple circuit patterns are formed on the wafer.

By using the mask for X-ray lithography of the present invention, it is possible to manufacture a highly integrated semiconductor device which has conventionally been difficult to manufacture.

[0090]

According to the present invention, it is possible to form a tungsten-containing alloy plating film having low stress, excellent in aging during use and process stability, and excellent in surface condition and accuracy.

Further, according to the present invention, it is possible to provide a mask for X-ray lithography which is excellent in high X-ray absorption, low stress, change over time during use and process stability, and furthermore has excellent surface condition and precision. .

Further, according to the present invention, heat resistance, low stress,
It is possible to provide a mold for molding which is excellent in aging and process stability during use, and is excellent in surface condition and precision.

[Brief description of the drawings]

FIG. 1 is a view showing a manufacturing process of a mask for X-ray lithography of the present invention.

FIG. 2 is a view showing a manufacturing process of a mask for X-ray lithography of the present invention.

FIG. 3 is a view showing a manufacturing process of a mask for X-ray lithography of the present invention.

FIG. 4 is a view showing a manufacturing process of the mask for X-ray lithography of the present invention.

FIG. 5 is a view showing an X-ray exposure step using the X-ray lithography mask of the present invention.

FIG. 6 is a diagram showing a step of manufacturing a device using a silicon wafer.

[Explanation of symbols]

 Reference Signs List 1 X-ray transmitting body (SiC) 2 Holder (Si substrate) 3 Base electrode (W) 4 Window for back etching 5 Resist 6 Plating alloy film (W-Ni) 7 Frame plate 8 Epoxy adhesive 11 SR light source 12 X Line 13 Mirror 14 X-ray stepper 15 Mask 16 Si wafer

Claims (20)

[Claims] 1. A step of forming a plating base electrode on the surface of a material to be plated, and any one of an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt by electrolytic plating on the plating base electrode. An electrolytic plating method comprising the step of: 2. A step of forming a plating base electrode on the surface of a material to be plated; a step of forming a pattern of a non-conductive substance having an opening of a predetermined shape on the plating base electrode; Depositing any one of an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt by an electrolytic plating method. 3. The electroplating method according to claim 1, wherein an aqueous solution containing (a) a tungsten compound, (b) any one of nickel, iron and cobalt, (c) an organic acid, and (d) ammonia is used as a plating solution. The electrolytic plating method according to claim 1 or 2, wherein 4. The method according to claim 3, wherein the organic acid is a mixture of malic acid and lactic acid. 5. The method according to claim 1, wherein the material of the base electrode is an alloy of tungsten with any one of molybdenum, titanium, cobalt, nickel, tin and iron.
5. The electrolytic plating method according to any one of 4. 6. An X-ray lithography mask having an alloy film of any of an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt as an X-ray absorber. 7. A step of forming a plating base electrode on the surface of the X-ray transmitting body, and forming an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt on the plating base electrode by electrolytic plating. 7. The method for producing a mask for X-ray lithography according to claim 6, comprising a step of depositing any one of them. 8. A step of forming an X-ray transmitting body on the surface of the silicon substrate, a step of forming a plating base electrode on the X-ray transmitting body, and forming a resist pattern having an opening of a predetermined shape on the plating base electrode. Forming a plating pattern by depositing any one of an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt in the resist opening by electrolytic plating; Removing the silicon substrate underneath from the opposite surface. 9. The electrolytic plating method according to claim 1, wherein an aqueous solution containing (a) a tungsten compound, (b) any one of nickel, iron and cobalt, (c) an organic acid, and (d) ammonia is used as a plating solution. The method for manufacturing a mask for X-ray lithography according to claim 7. 10. The method for producing a mask for X-ray lithography according to claim 9, wherein said organic acid is a mixture of malic acid and lactic acid. 11. The material of the base electrode is molybdenum,
8. An alloy of any one of titanium, cobalt, nickel, tin and iron and tungsten.
11. The method for producing a mask for X-ray lithography according to any one of items 10 to 10. 12. A molding die having an alloy film of any one of an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt on a surface of the mold. 13. A step of forming a plating base electrode on the surface of a mold material, and forming an alloy of tungsten and nickel, an alloy of tungsten and iron, and an alloy of tungsten and cobalt on the plating base electrode by electrolytic plating. The method for producing a mold according to claim 12, comprising a step of precipitating. 14. The electrolytic plating method according to claim 1, wherein an aqueous solution containing (a) a tungsten compound, (b) any one of nickel, iron and cobalt, (c) an organic acid, and (d) ammonia is used as a plating solution. The method for producing a mold for molding according to claim 12. 15. The method according to claim 14, wherein the organic acid is a mixture of malic acid and lactic acid. 16. The material of the base electrode is molybdenum,
2. An alloy of tungsten with any one of titanium, cobalt, nickel, tin and iron.
The method for producing a mold for molding according to any one of 3 to 15. 17. An X-ray lithography method using the X-ray lithography mask according to claim 6. 18. A method for manufacturing a semiconductor device by an X-ray lithography method using the mask for X-ray lithography according to claim 6. 19. A molding method using the mold for molding according to claim 12. 20. A plating solution for forming a tungsten alloy plating film, comprising: (a) a tungsten compound; (b) a compound of any of nickel, iron and cobalt; (c) a mixture of malic acid and lactic acid; and (d) an aqueous solution containing ammonia. .