JP3332839B2 - Thin film forming apparatus and thin film forming method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for forming a thin film, and more particularly to an apparatus and an electrode for a semiconductor element, an electrode and a protective film for a liquid crystal device, a protective film for a magneto-optical recording medium, and the like. It belongs to the technical field of a thin film forming method suitable for forming an antireflection film, an enhanced reflection film, and the like for an optical article.

[0002]

2. Description of the Related Art One of thin film forming methods is sputtering.

In conventional reactive sputtering, a compound or metal target is sputtered by introducing a mixed gas of a sputtering gas and a reaction gas into a reaction chamber, and a metal compound thin film is formed by a chemical reaction between target constituent atoms and the reaction gas. To form. In the case of an insulating compound target, a high-frequency power such as RF or microwave is supplied to cause discharge, so that the deposition rate is generally low. In the case of a metal target, a DC voltage can be supplied to cause a discharge,
The deposition rate can be increased.

[0004] Even when the target is a metal, the reaction gas reacts with the metal target on the target surface to form a metal compound on the target surface. In general, the sputtering yield for a metal compound is about 10% of the sputtering yield for a metal, so that the reactive sputtering results in a low deposition rate.

Even in the case of a compound target, the compound thin film formed becomes a film in which the actual content of metal atoms is higher than the content determined by the stoichiometric ratio. It is necessary to form a film having a composition close to the ratio. Further, in the case of a metal target, if the flow rate of the reaction gas is reduced, the formed metal compound thin film becomes a thin film having a high content of metal atoms, cannot be a thin film satisfying the stoichiometric ratio, and has optical characteristics (refractive index, transmittance). Etc.) and the properties of the thin film are inferior.

Therefore, several attempts to solve such technical problems have been proposed.

FIG. 10 is a schematic view of a reactive sputtering apparatus described in Japanese Patent Application Laid-Open No. Sho 62-56570. 1 is a target, 2 is a substrate, 3 is a supply pipe of argon (Ar) as a sputtering gas, 4 is a supply pipe of oxygen (O ₂ ) as a reaction gas, 9 is a reaction chamber, 12 is a target holder, and 7 is a substrate. Holder.

According to the above publication, when the apparatus shown in FIG. 10 is used, a sputtering gas and a reaction gas are introduced separately,
Since the sputtering is preferentially performed near the target and the oxidation reaction is preferentially performed near the substrate, the sputter rate is improved, and the properties of the oxide are likely to be improved.

However, in reality, the sputtering gas and the reaction gas are mixed between the target and the substrate, and a mixed plasma of the two is formed. In particular, when a thin film is formed on a large-area substrate, the discharge region between the substrate and the target also becomes large. Therefore, the film quality and the sputter rate cannot be improved as expected.

FIG. 11 is a schematic view of a reactive sputtering apparatus described in Japanese Patent Application Laid-Open No. Hei 6-41733. 1 is a target, 2 is a substrate, 3 is a supply pipe of argon (Ar) as a sputtering gas, 4 is a supply pipe of oxygen (O ₂ ) as a reaction gas, 9 is a reaction chamber, 12
Is a target holder, 7 is a substrate holder, 8 is a power supply,
9 is a reaction chamber, 12 is a target holder, 13 is a differential pressure plate, 14 is a high frequency power supply, 15 is an exhaust pump, 16 is a magnet, and 17 is a pipe for circulating a refrigerant.

In this apparatus, an exhaust port communicating with a vacuum pump is provided at the upper part of the reaction chamber 9, and a pressure difference is generated between the upper part and the lower part of the reaction chamber by using a differential pressure plate 13 to form a sputtering gas and a reactive gas. Trying to separate.

However, in the apparatus shown in FIG. 11, since the opening 13a of the differential pressure plate 13 is larger than the size of the substrate 2, the sputtering gas actually passes through the opening 13a of the differential pressure plate 13 to the substrate 2 side. And the discharge area becomes large. Therefore, even with this apparatus, the improvement of the sputtering rate and the improvement of the film characteristics are not improved as expected. Further, since the pre-excitation of oxygen by the high-frequency power supply 14 is required, the configuration of the apparatus becomes complicated. Further, the inner wall of the reaction gas supply pipe 4 is sputtered for the pre-excitation to supply the reaction gas such as iron. The adverse effects such as the constituents of the tube being taken into the film to be formed are greater.

Further, an excessive rise in temperature due to the sputtered particles jumping into the substrate is likely to occur.

A reactive sputtering apparatus proposed to achieve another object different from the above-mentioned apparatus is disclosed in Japanese Patent Laid-Open No. 7-33.
No. 5553. In this apparatus, a collie meter is provided between a target and a substrate to fill a contact hole of a semiconductor device.

In a conventional apparatus having a collimator, the angle of incidence of sputtered target constituent atoms on the substrate surface is reduced due to the large aspect ratio of the collimator, so that a continuous thin film having a uniform large area can be formed. difficult. Furthermore, the surface of the collimator is sputtered, and constituent atoms of the collimator (for example, iron when the collimator is stainless steel) are mixed into the TiN thin film to be formed.

Further, the specification and drawings of US Pat. No. 5,415,753 or the document "THE SECOND"
INTERNATIONAL SYMPOSIUM
ONSPUTTERING & PLASMA PRO
CESSES, 1993, pp 269-274 "
A reactive sputtering apparatus is described in which an apertured plate is disposed between a target and a substrate, and a sputtering gas and a reactive gas are separately supplied.

However, in this reactive sputtering apparatus, the electrical characteristics and materials of the plate with holes have not been sufficiently studied, and the characteristics of the film do not improve as expected.

Among the thin films, magnesium fluoride (MgF ₂ ) has attracted attention as a material having a low refractive index (1.38). However, when a film is formed by a sputtering method, light absorption often occurs. . Further, it is said that the deposition rate of magnesium fluoride by sputtering is lower than that of vacuum deposition.

For this purpose, a method in which the target is held through a heat insulating backing plate and the target temperature is kept high or a method using a MgF ₂ granular target is disclosed in JP-A-9-41132 and JP-A-9-41134. It is written in.

[0020]

However, all of the methods focus on improving the sputter rate or the film forming rate without sufficiently improving the film quality. A compound thin film having excellent electrical characteristics could not be obtained.

[0021]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film forming apparatus and a thin film forming method capable of forming a thin film having a uniform thickness and optical or electrical characteristics in a plane. .

The present invention provides a substrate holding means for holding a substrate, a target holding means for holding a target, a sputtering gas supply means for supplying a sputtering gas for sputtering the target into a reaction chamber, In a reactive sputtering apparatus including a reaction gas supply unit for supplying a reaction gas and a power supply unit for supplying electric power for causing a discharge between the target and the substrate, a reactive gas supply unit is provided between the target and the substrate. A partition member having a plurality of openings is provided, the sputtering gas is supplied to a space between the target and the partition member, and the reaction gas is supplied between the substrate and the partition member. A supply port for the sputtering gas and a supply port for the reaction gas are provided apart from each other, and a potential setting means for setting a potential of the partition member is provided. The features.

According to the present invention, the presence of the partition member at which the potential is set causes the plasma of the sputter gas to be separated from the substrate surface, so that it is possible to prevent adverse effects on the formed thin film.
In addition, since the reaction gas is preferentially bonded to atoms sputtered from the target on the substrate surface, a high-quality film having an extremely close stoichiometric ratio can be obtained.

Further, since the partition member captures a part of a large amount of sputtered target constituent atoms, an excessive rise in the substrate temperature due to the target constituent atoms jumping into the substrate can be suppressed.

Another object of the present invention is to provide a thin film forming apparatus and a thin film forming method capable of forming a uniform thin film of good quality at a high deposition rate.

According to the present invention, there is provided a substrate holding means for holding a substrate, a target holding means for holding a target, a sputtering gas supply means for supplying a sputtering gas for sputtering the target into a reaction chamber, A thin film forming apparatus comprising: a reaction gas supply unit for supplying a reaction gas; and a power supply unit for supplying electric power for causing discharge between the target and the substrate. A partition member having a plurality of openings is provided, the sputtering gas is supplied to a space between the target and the partition member, and the reaction gas is supplied between the substrate and the partition member. A supply port for the sputtering gas and a supply port for the reaction gas are provided apart from each other, and at least a surface of the partition member is made of the same material as the target. .

According to the present invention, since the plasma of the sputtering gas separates from the substrate surface due to the presence of the partition member, it is possible to prevent adverse effects on the formed thin film. In addition, since the reaction gas is preferentially bonded to atoms sputtered from the target on the substrate surface, a high-quality film having an extremely close stoichiometric ratio can be obtained. Even if the partition member is sputtered, it is a substance that does not affect the thin film to be formed, so that the inclusion of undesirable impurities is suppressed.

Further, since the partition member captures a part of a large amount of sputtered target constituent atoms, an excessive rise in the substrate temperature due to the target constituent atoms jumping into the substrate can be prevented.

Still another object of the present invention is to provide a thin film forming apparatus and a thin film forming method which can be applied to the formation of a thin film of a compound such as magnesium fluoride, which is considered to be relatively difficult to obtain good optical characteristics. It is in.

According to the present invention, there is provided a substrate holding means for holding a substrate, a raw material holding means for holding a raw material, a gas supply means for supplying a sputtering gas for sputtering the raw material, And a power supply means for supplying electric power for causing discharge between the substrates, comprising: a partition member having a plurality of openings between the raw material and the substrate; Is characterized in that at least the surface on the raw material side is coated with the same material as the raw material, and has a conductor to which a bias voltage is applied.

Further, the present invention provides a substrate holding means for holding a substrate, a raw material holding means for holding a raw material, a gas supply means for supplying a sputtering gas for sputtering the raw material, In a thin film forming method for forming a compound thin film using an apparatus having power supply means for supplying electric power for causing discharge between the raw material and the substrate, a substrate having a plurality of apertures sandwiched between the raw material and the substrate, And a raw material of the same material as the surface of the partition member, and a sputter gas is supplied to a space between the raw material and the partition member to cause a discharge between at least the raw material and the partition member, thereby forming the substrate. A film containing constituent atoms of the raw material is formed thereon.

According to the present invention, since the plasma of the sputtering gas is separated from the substrate surface by the presence of the partition member, it is possible to prevent adverse effects on the formed thin film. Further, even if the partition member is sputtered, it is a substance which does not affect the thin film to be formed, so that the inclusion of undesirable impurities is suppressed.

Further, since the partitioning member captures a part of a large amount of sputtered target constituent atoms, an excessive rise in the substrate temperature due to the target constituent atoms jumping into the substrate can be prevented. When a DC bias is applied to the partition member, the penetration of ions from the target side to the substrate surface is prevented.

In this way, it is possible to form a compound thin film having a uniform thickness and optical or electrical characteristics in the plane. In the present invention, a compound thin film such as magnesium fluoride, which is relatively difficult to form, can be easily formed.

[0035]

FIG. 1 is a schematic sectional view of a thin film forming apparatus using reactive sputtering according to a preferred embodiment of the present invention.

(Thin Film Forming Apparatus) The apparatus shown in FIG. 1 comprises a substrate holder 7 as a substrate holding means for holding the substrate 2,
A target holder 12 as a target holding means for holding the target 1, and a gas shower head 3 as a sputtering gas supply means for supplying a sputtering gas GA for sputtering the target 1 into the reaction chamber 9.
And a gas shower head 4 as a reaction gas supply unit for supplying a reaction gas GB, and a power supply 8 as a power supply unit for supplying electric power for generating plasma 5 by electric discharge between the target 1 and the substrate 2. Have. Then, a grid plate 6 as a partition member having a plurality of openings 6a is provided between the target 1 and the substrate 2, and a sputter gas GA is supplied to a space between the target 1 and the grid plate 6, and A supply port 10 for the sputter gas GA and a supply port 11 for the reaction gas GB are provided separately from each other so as to supply the reaction gas GB between the grid gas and the grid plate 6. Further, the grid plate 6 is maintained at a predetermined potential during sputtering by potential setting means including a switch SW.

FIG. 2 is a plan view showing an example of a partition member 6 composed of a mesh, an apertured plate or the like suitably used in the present invention, and FIG. 3 is a sectional view of the partition member 6. The material of at least the surface of the grid plate 6 as the partition member is selected according to the constituent material of the target 1 to be sputtered. In other words, the material of the grid plate 6 should be selected according to the constituent material of the film to be formed. For example, when a silicon oxide film is formed, a member made of silicon (Si) is used. When a tantalum oxide film is formed, a member made of tantalum (Ta) is used. When an aluminum oxide film is formed. Uses a member made of aluminum (Al). Thus, the grid plate is made of silicon (Si), tantalum (Ta), aluminum, magnesium (Mg),
It is selected from materials such as indium (In), titanium (Ti), copper (Cu), and tungsten (W). The grid plate uses a conductive or insulating or semiconductive material selected independently of the target material as its base material, and a coating made of the same material as the target is formed on at least the surface of the base material facing the target 1 side. Plate member.

A plurality of openings 6a provided in the grid plate 6
Has an aspect ratio of less than 1.0, more preferably 0.1.
Desirably less than 6. Thereby, mutual diffusion of gas is suppressed, and a film can be formed at an appropriate deposition rate, and a film having a uniform film thickness over the entire surface can be obtained.

The three-dimensional shape of the opening viewed from the top surface of the grid plate may be a cylinder, a prism, or the like. The planar shape of the opening, that is, the opening shape (two-dimensional shape) may be any of a circle, an ellipse, a square, a triangle, and the like. Shape.

The aspect ratio AR of the opening 6a is defined as a value (D / L) obtained by dividing the depth (thickness of the plate) D of the opening by the diameter L of a perfect circle having the same area as the opening. You. Further, when the surface of the substrate is circular, the diameter L is preferably 1% to 15%, more preferably 4% to 10% of the diameter of the substrate 2.

Further, in order to form a uniform film, it is preferable that the plurality of openings 6a of the grid plate 6 are regularly distributed. The aperture ratio is 5% to 90%, more preferably 20% to obtain a uniform large-area thin film at an appropriate deposition rate.
To 70% is desirable.

Then, the grid plate is subjected to sputtering in a state of being electrically floating or, more preferably, being biased to a predetermined potential so as to generate a potential difference between the grid plate and the target. SW is a switch that is a potential setting unit for setting the bias potential of the grid plate 6 and is also a potential switching unit. The grid plate 6 and the substrate 2 may have the same potential or may have different potentials. In addition, the grid plate 6 and the chamber may have different potentials. The grid plate 6 is biased to a positive or negative potential with respect to the target side.
It is preferred. In order to further increase the sputter rate, the power to be supplied may be increased. However, in this case, sputtered atoms jump into the substrate too much, and the substrate temperature is excessively increased. In this case, a film cannot be formed on a substrate that does not like thermal deformation. In this example, such a problem can be solved because the grid plate captures the sputtered atoms.

As shown in FIG. 1, it is desirable that a plurality of the sputter gas supply ports 10 are arranged near the target 1 and so as to surround the target 1. In the apparatus shown in FIG. 1, the sputter gas supply port 10 is located closer to the target 1 than the center of the tube, and is configured to blow out gas preferentially to the target 1 side. The sputter gas supply ports 10 are arranged at substantially equal intervals on the gas shower head 3 which is an annular supply pipe. In other words, it can be said that a plurality of supply ports are arranged symmetrically on the circumference.

Similarly, it is desirable that a plurality of the reaction gas supply ports 11 are arranged near the substrate 2 and so as to surround the substrate 2. In the apparatus shown in FIG. 1, the reaction gas supply port 11 is located on the substrate 2 side from the center of the tube, and is configured to blow out gas preferentially to the substrate surface. The reaction gas supply ports 11 are arranged at substantially equal intervals on the gas shower head 4 which is an annular supply pipe. In other words, it can be said that a plurality of supply ports are symmetrically arranged on the circumference.

The substrate holding means 7 is configured to be able to rotate at 1 to 50 rpm during sputtering. Thereby, a more uniform film can be obtained.

A magnet may be arranged on the target holder 12 to perform reactive magnetron sputtering.
By doing so, the plasma of the sputtering gas is confined closer to the target.

Although a DC power supply is shown as the power supply 8, an AC power supply can be used instead. AC
As the power supply, for example, a 13.56 MHz RF power supply may be used, and a DC bias may be superimposed as necessary. In order to further increase the deposition rate of the thin film by increasing the sputtering rate, it is desirable to perform DC sputtering using a DC power supply.

The exhaust port of the reaction chamber 9 is connected to an exhaust pump (not shown). The exhaust pump can be configured by combining a turbo molecular pump or a cryopump for main exhaust with a rotary pump for rough exhaust, or the like.

FIG. 1 shows an apparatus in which the target 1 is placed above and the substrate is placed below. The relationship is turned upside down and the substrate is placed above so that the surface on which the film is to be formed faces downward. Then, the target may be arranged downward so that the surface to be sputtered faces upward. Alternatively, a substrate or target on a flat plate may be placed upright so that the film formation surface and the surface to be sputtered are non-horizontal.

(Film Forming Method) Hereinafter, a thin film forming method for forming a thin film using the above-described reactive sputtering apparatus will be described.

First, the target 1 and the substrate 1 are placed in the reaction chamber 9.
And the partition member 6 are arranged. At this time, the target 1 and the partitioning member 6 are selected from the same material.

First, a partition member having a plurality of openings is arranged. Then, place the target 1 in the target holder 1
2 above. Subsequently, the substrate 2 is placed on the substrate holder 7.

The inside of the reaction chamber 9 is evacuated, and the substrate 2 is
Is cooled or heated.

The sputter gas GA is supplied from the supply port 10 of the gas shower head 3 to the space between the target 1 and the partition member 6, and the supply port 1 of the reaction gas shower head 4 is supplied.
1 to supply a reaction gas GB between the substrate 2 and the partition member 6.

With the pressure in the reaction chamber maintained at about 0.05 to 13 Pascal, more preferably about 0.1 to 1.3 Pascal, a DC voltage is applied between the target 1 and the substrate 2.
By applying a voltage or an RF voltage, a discharge is generated between the target 1 and the biased partition member 6 to generate a plasma 5 of a sputtering gas. The constituent atoms of the target sputtered by the plasma particles reach the surface of the substrate 2 through the openings 6a of the grid plate 6. Here, in the space between the grid plate 6 and the substrate 2, there is a reaction gas that reacts with the target constituent atoms, so that it reacts on the substrate surface, and the target constituent atoms and the constituent atoms of the reaction gas are separated. A film including the same can be formed over a substrate.

According to this embodiment, since the grid plate 6 is made of the same material as the target 1, even if the plasma particles sputter the grid plate 6, the thin film formed on the substrate 2 is not affected. . Since the grid plate prevents the reaction gas from flowing out to the target side, the reaction between the reaction gas and the sputtered target constituent atoms occurs preferentially on the substrate surface. In this way, a thin film having a very close stoichiometric ratio can be formed at a high deposition rate without lowering the sputtering rate.

The surface material of the target and the partition member used in the present invention is a conductive material such as Si, Al, Ta, In, tin (Sn), Ti, Cu, zinc (Zn), Mg, and W. .

As a sputtering gas, He, Ne, Ar,
Kr, Xe, Rn and the like.

As the reaction gas, O ₂ , N ₂ , F ₂ , NF ₃ ,
O _{3 and the} like.

The substrate may be translucent or non-translucent, and may be made of a semiconductor substrate such as silicon or GaAs, or an insulating substrate such as glass, quartz, or fluorite. And metal substrates such as stainless steel and aluminum.

As a thin film that can be formed, silicon oxide, aluminum oxide, aluminum fluoride, tantalum oxide,
It is a compound thin film of indium oxide, tin oxide, titanium nitride, copper oxide, zinc oxide, magnesium fluoride, tungsten nitride, or the like.

The reactive sputtering apparatus of the present invention is particularly effective when forming an optical thin film on a transparent or insulating substrate surface having a concave or convex surface, and the optical sputtering apparatus obtained by the thin film forming method of the present invention. The thin film exhibits excellent properties as an antireflection film or an enhanced reflection film of a high energy KrF excimer laser or ArF excimer laser optical article.

When films having different compositions are formed using the same reactive sputtering apparatus, it is preferable to make the partition member detachable from the reaction chamber so that the partition member can be replaced.

The sputtered atoms adhere to the grid plate. In particular, it may adhere to the corner of the opening on the target side to close the opening. Therefore, so as not to fill the opening
It is preferable that the corner of the opening be chamfered to be tapered. FIG. 4 is a partial sectional view showing such a tapered opening 6a of the grid plate 6. As shown in FIG. As is clear from comparison with FIG. 3, the corner 6b is chamfered. This reduces the frequency of grid plate replacement and extends the continuous use time of the device.

Example 2 The reactive sputtering apparatus shown in FIG. 5 has a substrate holder 7 as a substrate holding means for holding the substrate 2 and a target as a target holding means for holding the target 1 as a raw material. Holder 1
2 and a gas shower head 3 as a sputtering gas supply means for supplying a sputtering gas GA for sputtering the target 1 into the reaction chamber 9 for supplying a reaction gas GB provided as necessary. Has a gas shower head 4 as a reactive gas supply means. Further, a power source 8 is provided between the target 1 and the substrate 2 as power supply means for supplying power for generating plasma 5 by discharge. Then, a grid plate 6 as a partition member having a plurality of openings 6a between the target 1 and the substrate 2
Is provided. The grid plate has at least the target side coated with the same material as the target, and has a conductor to which a bias voltage is applied from the bias voltage source. The supply port 10 for the sputter gas GA and the supply port 10 for the sputter gas GA are supplied as necessary so that the sputter gas GA is supplied to the space between the target 1 and the grid plate 6 and the reaction gas GB is supplied between the substrate 2 and the grid plate 6. It is preferable that the supply ports 11 for the reaction gas GB are provided separately from each other.

The partition member 6 used in this embodiment has the same planar shape as that shown in FIG. FIG. 6 is a sectional view of the partition member 6. The material of at least the surface 6c of the grid plate 6 as the partition member is selected according to the constituent material of the target 1 to be sputtered. In other words, the material of the surface of the grid plate 6 should be selected according to the constituent material of the film to be formed. For example, when a magnesium fluoride film is formed, a conductive member covered with magnesium fluoride may be used. In addition, when a silicon oxide film is formed, a conductive member coated with silicon oxide is used.When a tantalum oxide film is formed, a conductive member coated with tantalum oxide is used to form an aluminum oxide film. When forming a film, a conductive member coated with aluminum oxide is used. As described above, the grid plate is selected from materials such as silicon oxide, tantalum oxide, aluminum oxide, magnesium fluoride, indium oxide, titanium nitride, and copper oxide.
For the grid plate, a conductive or semiconductive material selected independently of the target material can be used as the base material, and a compound film made of the same material as the target is formed on the surface of the base material facing at least the target 1 side. It may be a plate-shaped member.

A plurality of openings 6 a provided in the grid plate 6
Has an aspect ratio of less than 1.0, more preferably 0.1.
Desirably less than 6. Thereby, mutual diffusion of gas is suppressed, and a film can be formed at an appropriate deposition rate, and a film having a uniform film thickness over the entire surface can be obtained.

The three-dimensional shape of the opening viewed from the top surface of the grid plate may be a cylinder, a prism, or the like. The planar shape of the opening, that is, the opening shape (two-dimensional shape) may be any of a circle, an ellipse, a square, a triangle, and the like. Shape.

The aspect ratio AR of the opening 6a is defined as a value (D / L) obtained by dividing the depth D of the opening (thickness of the plate) by the diameter L of a perfect circle having the same area as the opening. You. Furthermore, the diameter L is 1% to 15% of the diameter of the substrate 2, more preferably
4% to 10% is desirable.

Further, in order to form a uniform film, it is preferable that the plurality of openings 6a of the grid plate 6 are regularly distributed. The aperture ratio is 5% to 90%, more preferably 20% to obtain a uniform large-area thin film at an appropriate deposition rate.
To 70% is desirable.

Then, sputtering is performed in a state where the grid plate is maintained at a predetermined positive or negative potential so as to generate a potential difference between the grid plate and the target. Reference numeral 42 denotes a bias voltage source as potential setting means for setting the potential of the grid plate 6. In the apparatus shown in FIG.
It is better to bias to a higher potential and to bias grid plate 6 to a lower potential than the chamber. By doing so, it is possible to suppress the impact of negative ions from the plasma entering the substrate side and exerting on the film. In order to further increase the sputter rate, the power to be supplied may be increased. However, in this case, sputtered atoms jump into the substrate too much, and the substrate temperature is excessively increased. In this case, a film cannot be formed on a substrate that does not like thermal deformation. In this example, such a problem can be solved because the grid plate partially captures the sputtered atoms.

It is preferable that a plurality of the sputter gas supply ports 10 are arranged near the target 1 and surrounding the target 1 as shown in FIG. In the apparatus shown in FIG. 1, the sputter gas supply port 10 is located closer to the target 1 than the center of the tube, and is configured to blow out gas preferentially to the target 1 side. The sputter gas supply ports 10 are arranged at substantially equal intervals on the gas shower head 3 which is an annular supply pipe. In other words, it can be said that a plurality of supply ports are arranged symmetrically on the circumference.

Similarly, it is desirable that a plurality of the reaction gas supply ports 11 are arranged near the substrate 2 and so as to surround the substrate 2. In the apparatus shown in FIG. 1, the reaction gas supply port 11 is located on the substrate 2 side from the center of the tube, and is configured to blow out gas preferentially to the substrate surface. The reaction gas supply ports 11 are arranged at substantially equal intervals on the gas shower head 4 which is an annular supply pipe. In other words, it can be said that a plurality of supply ports are symmetrically arranged on the circumference.

The substrate holding means 7 is configured to be able to rotate at 1 to 50 rpm during sputtering. Thereby, a more uniform film can be obtained. And the grid plate 6
It is kept at a lower potential.

Reactive magnetron sputtering may be performed by disposing a magnet on the target holder 12.
By doing so, the plasma of the sputtering gas is confined closer to the target.

An AC power supply is used as the power supply 8. As the AC power supply, for example, 13.56 MHz RF
There is a power supply and a DC bias may be superimposed as needed.

The exhaust port of the reaction chamber 9 is connected to an exhaust pump (not shown). The exhaust pump can be configured by combining a turbo molecular pump or a cryopump for main exhaust with a rotary pump for rough exhaust, or the like.

FIG. 1 shows an apparatus in which the target 1 is arranged upward and the substrate is arranged downward. This relationship is reversed, and the substrate is arranged upward such that the film-forming surface thereof faces downward. Then, the target may be arranged downward so that the surface to be sputtered faces upward. Alternatively, a substrate or target on a flat plate may be placed upright so that the film formation surface and the surface to be sputtered are non-horizontal.

Hereinafter, a method of forming a thin film using the above-described reactive sputtering apparatus will be described.

First, the target 1 and the substrate 1 are placed in the reaction chamber 9.
And the partition member 6 are arranged. At this time, the target 1 and the target side surface of the partitioning member 6 are selected from the same material.

First, a partition member having a plurality of openings is arranged. Then, place the target 1 in the target holder 1
2 above. Subsequently, the substrate 2 is placed on the substrate holder 7.

The inside of the reaction chamber 9 is evacuated, and the substrate 2 is
Heat.

The sputtering gas GA is supplied from the supply port 10 of the gas shower head 3 to the space between the target 1 and the partition member 6, and the supply port 1 of the reaction gas shower head 4 is supplied.
1 to supply a reaction gas GB between the substrate 2 and the partition member 6.

While maintaining the pressure in the reaction chamber at about 0.05 to 13 Pascal, more preferably about 0.1 to 1.3 Pascal, a DC voltage is applied between the target 1 and the substrate 2.
By applying a voltage or an RF voltage, a discharge is generated between the target 1 and the partition member 6 to generate a plasma 5 of a sputtering gas. The constituent atoms of the target sputtered by the plasma particles reach the surface of the substrate 2 through the openings 6a of the grid plate 6. Here, the grid plate 6 and the substrate 2
Since there is a reaction gas that reacts with the target constituent atoms in the space between the target gas and the target gas, it reacts on the substrate surface to form a film containing the target constituent atoms and the reaction gas constituent atoms on the substrate. Can be.

According to this embodiment, since the grid plate 6 is made of the same material as the target 1, even if the plasma particles sputter the grid plate 6, the thin film formed on the substrate 2 is not affected. . Since the grid plate prevents the reaction gas from flowing out to the target side, the reaction between the reaction gas and the sputtered target constituent atoms occurs preferentially on the substrate surface. In this way, a thin film having a very close stoichiometric ratio can be formed at a high deposition rate without lowering the sputtering rate.

The constituent material of the target used in the present invention and the constituent material of the surface of the partition member are Si
O ₂ , Al ₂ O ₃ , Ta ₂ O ₅ , InO, SnO ₂ , TiN,
Compounds such as Cu ₂ O, ZnO, MgF ₂ and WN.

As the sputtering gas, He, Ne, Ar,
Kr, Xe and the like.

As the reaction gas, O ₂ , N ₂ , F ₂ , NF ₃ ,
O _{3 and the} like.

The substrate may be translucent or non-translucent, and may be made of a semiconductor substrate such as silicon or GaAs, or an insulating substrate such as glass, quartz, or fluorite. And metal substrates such as stainless steel and aluminum.

The thin films that can be formed include silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, aluminum fluoride, tantalum oxide, tantalum nitride, indium oxide, tin oxide, titanium oxide, titanium nitride, copper oxide, zinc oxide, and tungsten nitride. , Magnesium fluoride and the like.

In particular, the reactive sputtering apparatus of the present invention is effective for forming an optical thin film on a transparent or insulating substrate surface having a concave or convex surface, and the optical sputtering apparatus obtained by the thin film forming method of the present invention. The thin film exhibits excellent properties as an antireflection film or an enhanced reflection film of a high energy KrF excimer laser or ArF excimer laser optical article.

In the case where films having different compositions are formed using the same reactive sputtering apparatus, it is preferable to make the partition members replaceable.

Further, the sputtered atoms adhere to the grid plate. In particular, it may adhere to the corner of the opening on the target side to close the opening. Therefore, so as not to fill the opening
It is preferable that the corner of the opening be chamfered to be tapered. Then, the surface is coated with the same material as the target. FIG. 7 is a partial sectional view showing such a tapered opening 6a of the grid plate 6. As shown in FIG. As is clear from comparison with FIG. 6, the corner 6b is chamfered. This reduces the frequency of grid plate replacement and extends the continuous use time of the device.

(Embodiment 3) Still another preferred embodiment of the present invention will be described. FIG. 8 is a modification of the embodiment of FIG. 5 described above, in which a cylindrical shield member 31 is provided around the grid plate 6. Shield member 31
Plays a role of a deposition-preventing plate for preventing sputtered target constituent atoms from adhering to the walls of the reaction chamber, and a role of improving the effect of confining sputter gas and the effect of confining reaction gas. In this example, the gap between the upper end of the shield member 31 and the target 1 becomes the exhaust path 20 for the sputter gas GA,
The gap between the shield member 31 and the gas shower head 4 and the gap between the gas shower head 4 and the substrate 2 are the reaction gas GB.
Exhaust path 21. Sputter gas GA is arrow 2
The fluid flows to the communication port 24 communicating with the exhaust pump through the second route.
The reaction gas GB flows to the communication port 24 along the path shown by the arrow 23. If the conductances of the exhaust portions 22 and 23 are made larger than the conductance of the openings of the grid plate 6, mutual diffusion of gas that has an adverse effect can be prevented.

It is desirable that the shield member 31 be made of the same material as the grid plate. That is, it is desirable that at least the inner surface of the shield member 31 be coated with the same material as the target. It is desirable that the potential be maintained at the same potential as the grid plate. The shield member 31 is supported by support legs 32 provided on an insulator 33 as an insulating member provided on the bottom surface of the reaction chamber.
The bias voltage source 42, the substrate bias voltage source 43, and the blocking capacitor 41 are configured in the same manner as the device shown in FIG.

(Embodiment 4) FIG. 9 is a schematic view showing another embodiment of the present invention. In this embodiment, a communication port 25 exclusively for exhausting a sputter gas for exhausting a space between the grid plate 6 and the target 1 is provided, and a communication exclusive for a reaction gas exhaust for exhausting a space between the grid plate 6 and the substrate. The mouth 26 is provided.

An exhaust pipe is connected to the shield member 31 on the grid plate 6, and a communication port 25 as an exhaust portion is formed. Reference numeral 27 denotes a valve which can open and close the exhaust path and adjust the conductance.

An exhaust pipe is connected to the shield member 31 below the grid plate 6, and a communication port 26 as an exhaust portion is formed. Reference numeral 28 denotes a valve which can open and close the exhaust path and adjust the conductance.

An insulator 29 as an insulating member is provided in the middle of the two exhaust paths to insulate the reaction chamber from the shield member.

Further, a communication port 24 is provided in the reaction chamber 9 similarly to the apparatus shown in FIG. During the film formation, the valve 30 can be opened to exhaust air. At this time, the gap 20 between the target 1 and the shield member 31 and the gap 21 between the shield member 31 and the substrate 2 still function as an exhaust passage at all.

In the case of this example, the pressure on the exhaust side of the sputtering gas from the communication port 25 is higher than the pressure on the exhaust side of the reaction gas from the communication port 26, and the pressure in the plasma space where plasma is generated is higher than the pressure in the space on the substrate side. It is desirable. This makes it more difficult for the reaction gas to flow into the plasma space. Specifically, first, the valves 27 and 28 are closed,
The valve 30 is opened to evacuate the reaction chamber. Next, the valve 30 is closed, and the valves 27 and 28 are opened to change the exhaust path, and at the same time, the sputtering gas and the reaction gas are introduced from the gas shower heads 3 and 4 into the reaction chamber. Thus, the sputtering gas is introduced from the supply port 10 into the first space, and is exhausted from the first space through the communication port 25. The reaction gas is introduced from the supply port 11 into the second space, and is exhausted from the second space via the communication port 26. The switch SW having the same configuration as that shown in FIG. 1 is used.

[0102]

According to the present invention, it is possible to form a compound thin film having a uniform thickness and optical or electrical characteristics in a plane.

Further, a compound thin film having a uniform large area can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic view of a thin film forming apparatus according to a preferred embodiment of the present invention.

FIG. 2 is a plan view of a partition member used in the thin film forming apparatus of the present invention.

FIG. 3 is a sectional view of a partition member used in the thin film device of the present invention.

FIG. 4 is a partial cross-sectional view near an opening of another partition member used in the present invention.

FIG. 5 is a schematic view of a thin film forming apparatus according to another embodiment of the present invention.

FIG. 6 is a sectional view of another partition member used in the thin film forming apparatus of the present invention.

FIG. 7 is a partial sectional view of still another partition member used in the present invention.

FIG. 8 is a schematic view showing a thin film forming apparatus according to another embodiment of the present invention.

FIG. 9 is a schematic view showing a thin film forming apparatus according to still another embodiment of the present invention.

FIG. 10 is a schematic view showing one example of a conventional reactive sputtering apparatus.

FIG. 11 is a schematic view showing another example of a conventional reactive sputtering apparatus.

[Explanation of symbols]

 Reference Signs List 1 target 2 substrate 3, 4 gas shower head 5 plasma 6 partition member (grid plate) 7 substrate holder 8 power supply 9 reaction chamber 10 sputter gas supply port 11 reaction gas supply port 12 target holder 20, 21 exhaust path 25, 26 communication port (Exhaust path) 31 Shielding member 41 Blocking capacitor 42 Bias voltage source 43 Substrate bias voltage source

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-99461 (JP, A) JP-A-6-136527 (JP, A) JP-A-6-295903 (JP, A) JP-A 63-99903 151355 (JP, A) JP-A-9-7949 (JP, A) JP-A-61-261472 (JP, A) JP-A-5-255848 (JP, A) JP-A-63-303064 (JP, A) JP-A-8-188870 (JP, A) JP-A-8-209342 (JP, A) JP-B-61-27462 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 H01L 21/203 H01L 21/285

Claims (10)

(57) [Claims] 1. A thin film for supplying a substrate, a target, a reaction gas, and a sputtering gas into a reaction chamber and forming a thin film having a material for forming the target by reactive sputtering and a component of the reaction gas on the substrate. In the forming apparatus, a partition member having an opening that partitions the reaction chamber to form the space on the substrate side and the space on the target side, and a reaction gas supply unit that supplies the reaction gas to the space on the substrate side A reaction gas exhaust unit that exhausts the reaction gas from the space on the substrate side; a sputtering gas supply unit that supplies the sputtering gas to the space on the target side; and a sputtering that exhausts the sputtering gas from the space on the target side. Gas exhaust means, wherein the aspect ratio of the opening is less than 0.6, and the diameter of the opening is 1 of the diameter of the substrate. To 15%, and the pressure in the space on the target side is made higher than the pressure in the space on the substrate side by making the exhaust pressure of the sputtering gas exhaust means higher than the exhaust pressure of the reaction gas exhaust means. A thin film forming apparatus characterized by the above-mentioned. 2. The method according to claim 1, wherein said sputtering gas supply means comprises Kr, X
2. The thin film forming apparatus according to claim 1, wherein at least one kind of gas among e is supplied. 3. The diameter of the opening is four times the diameter of the substrate.
3. The thin film forming apparatus according to claim 1, wherein the thickness is in the range of 10% to 10%. 4. The partition member has an aperture ratio of 5% to 90%.
The thin film forming apparatus according to claim 1, wherein the ratio is%. 5. The partition member has an aperture ratio of 20% to 7%.
5. The method according to claim 1, wherein the value is 0%.
Item 7. The thin film forming apparatus according to Item 1. 6. A thin film that supplies a substrate, a target, a reaction gas, and a sputtering gas into a reaction chamber and forms a thin film having a material for forming the target and a component of the reaction gas on the substrate by reactive sputtering. In the forming apparatus, a partition member having an opening that partitions the reaction chamber to form the space on the substrate side and the space on the target side, and a reaction gas supply unit that supplies the reaction gas to the space on the substrate side And a sputtering gas supply unit for supplying the sputtering gas to the space on the target side, wherein an aspect ratio of the opening is less than 0.6, and a diameter of the opening is 1% of a diameter of the substrate. To 15%. 7. The sputtering gas supply means comprises: Kr, Xr
7. The thin film forming apparatus according to claim 6, wherein at least one kind of gas among e is supplied. 8. The diameter of the opening is four times the diameter of the substrate.
The thin film forming apparatus according to claim 6, wherein the thickness is in the range of 10% to 10%. 9. The partition member has an aperture ratio of 5% to 90%.
The thin film forming apparatus according to any one of claims 6 to 8, wherein the percentage is%. 10. The thin film forming apparatus according to claim 6, wherein an aperture ratio of the partition member is 20% to 70%.