JP2004165655A - Sputtering system and method of manufacturing thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sputtering system capable of depositing high-quality thin films containing no impurities, and a method of manufacturing the high-quality thin films using the sputtering system. <P>SOLUTION: In order to suppress impurities generated from a target shield, the surface of an adhesion-proof plate, a backing plate, a substrate holder, the surface of a shutter, the wall surface inside a chamber, etc., there is provided a sputtering system having the surfaces and the wall surfaces of the components coated with a thermal spraying material consisting of the same quality of material as the target material and the oxide or nitride of the target material. There is provided a method of manufacturing thin films consisting of the same quality of material as the target material, and the oxide of the target material or the nitride of the target material by using the sputtering system equipped with the target material representative of a semiconductor material and the components coated with the thermal spraying material with the same quality of material as the target material to apply high-frequency power in an atmosphere containing noble gases. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a sputtering device. The present invention also relates to a method for forming a thin film by a sputtering method.

  2. Description of the Related Art In recent years, a technology of forming a transistor typified by a thin film transistor (TFT) on an insulating surface, arranging pixels combined with the transistor and an EL (electroluminescence) element or the like in a matrix to form a screen for displaying information. Is being developed. This pixel is formed by an element having a thin film, an electrode, and the like formed by a sputtering method, a CVD method, or the like.

  In order to form a high-quality thin film using a sputtering method, a reaction chamber, a hydrogen cylinder, a vacuum pump, a substrate holder and a semiconductor target are included, and the semiconductor target and the substrate holder face each other at a distance of 90 mm or more. (See, for example, Patent Document 1).

JP-A-2001-144017 (pages 2 and 3)

  When a chemical or physical reaction is performed using plasma, such as a conventional plasma CVD method or a sputtering method, a thin film having poor characteristics is formed due to various causes such as generation of dust during a film forming process. As a result, the product yield has been reduced.

  When the film formed by the sputtering method was analyzed, impurities such as iron (Fe), nickel (Ni), and chromium (Cr) were detected. The reasons for the detection of these impurities are as follows: (1) Micro arc (local and instantaneous abnormal discharge in plasma) occurs between the target and the target shield, and between the target and the deposition-preventing plate, and deposits on the wall surface in the chamber. Fine dust (particles) may be generated due to peeling of the thin film, (2) plasma may be generated in the vicinity of the target shield and the protection plate, and (3) environmental pollution may be generated. In particular, silicon, which plays a role as an active layer in a TFT, affects the characteristics of the TFT, so that a high-quality film containing no impurities has been required.

  In view of the above circumstances, an object of the present invention is to provide a sputtering apparatus that can form a high-quality thin film containing no impurities. Another object is to provide a method for manufacturing a high-quality thin film using the sputtering apparatus.

The present invention is intended to suppress impurities generated from a target shield, a surface of a deposition-preventing plate (hereinafter collectively referred to as a shield), a backing plate, a surface of a substrate holder and a shutter, a wall surface in a chamber, and the like. Provided is a sputtering apparatus in which a wall surface is coated with the same material as a target material, and a thermal spray made of oxide or nitride of the target material. For example, there is provided a sputtering apparatus in which a semiconductor material typified by silicon is used as a target material, and the surface or the wall surface of the component is coated with the semiconductor material, or a spray of the oxide or nitride of the semiconductor material.
Note that the entire surface of the component need not be coated with the thermal spray, and only the portion exposed to the plasma may be coated with the thermal spray. In addition, the surface of only the target shield, only the deposition-preventing plate, or only the target shield and the deposition-preventing plate may be coated with the sprayed material.
The present invention also provides a target material and a component coated with a sprayed material, wherein a thin film formed on a substrate provided opposite to the target material is made of the same material, oxide or nitride as the sprayed material. Is provided. For example, a semiconductor material typified by silicon is used as a target material, and the surface of the shield is covered with the semiconductor material, or an oxide or nitride of the semiconductor material. In addition, a thin film formed on the substrate provided opposite to the target material is provided with a sputtering device which is the same material as the semiconductor material, or an oxide or nitride of the semiconductor material.
Further, the present invention uses a target material typified by a semiconductor material and a sputtering apparatus including a component coated with a sprayed material of the same material as the target material, and applying high-frequency power in an atmosphere containing a rare gas. Accordingly, a method for producing a thin film made of the same material as the target material, an oxide of the target material, or a nitride of the target material is provided.
When the thin film to be formed is a semiconductor, the target material and the sprayed material need to be the same material (semiconductor). When the thin film to be formed is an oxide of a semiconductor material, the target material and the sprayed material need to be a semiconductor material or an oxide of a semiconductor material. When the thin film to be formed is a nitride of a semiconductor material, the target material and the sprayed material need to be a semiconductor material or a nitride of a semiconductor material.

  As described above, in the present invention in which a sprayed material is provided, it is possible to prevent the shield material from scattering from the surface of a component such as a shield. Further, in the present invention, even if the shielding material is mixed in the thin film to be formed, the thin film does not have any adverse effect. Therefore, according to the present invention, a sputtering apparatus for forming a high-quality thin film containing no impurity can be provided. Further, a method for manufacturing a high-quality thin film using the sputtering apparatus of the present invention can be provided. Furthermore, according to the present invention, a high-quality thin film can be formed with a high yield, and the productivity of an element using the thin film can be improved.

  According to the present invention, a sputtering apparatus which forms a high-quality thin film containing no impurity element can be provided. Further, a method for manufacturing a high-quality thin film using the sputtering apparatus of the present invention can be provided. Further, according to the present invention, a high-quality thin film can be formed with a high yield, and the productivity of an element using the thin film can be improved.

  The configuration of the sputtering apparatus of the present invention will be described with reference to FIG.

The target 19 is cooled (water-cooled) by the refrigerant 24 via the backing plate. The permanent magnet 18 makes it possible to form a film with uniform film thickness on the opposing substrate surface by making a circular motion or a linear motion in a direction parallel to the target surface. The shutter 14 opens and closes before and after the start of film formation, and prevents the formation of a film when the plasma at the beginning of discharge is in an unstable state.
The substrate holding means 11 places the substrate on the holder 25 up and down and fixes it to the back plate 13. A sheath heater is embedded in the back plate 13 as the heating means 12, and further, a heated rare gas is introduced from the back side of the substrate 22 to increase the uniformity of heat. A gas suitable for the film to be formed is introduced from the gas introduction means 10 via the gas introduction pipe 26 in addition to the rare gas, and the pressure in the chamber is controlled by the conductance valve 20. The rectifying plate 21 is provided for the purpose of rectifying the flow of the sputtering gas in the room. The target 19 is connected to a high-frequency power supply, and sputtering is performed by applying high-frequency power. The gate valve 15 is used when connecting to another film forming chamber when the gate valve 15 is incorporated in a multitasking type manufacturing apparatus having a plurality of processing chambers.

The deposition-preventing plate 16 and the target shield 17 are disposed near the substrate 22 and the target 19 and prevent the sputtered particles of the sputtered target 19 from scattering and contaminating the inner wall in the chamber. Generally, stainless steel or the like is often used for the deposition-preventing plate 16 and the target shield 17.
In the present invention, the surfaces of components such as the backing plate, the shutter 14, the deposition-preventing plate 16, the target shield 17, and the inner wall of the chamber are coated with a sprayed material. Specifically, the coating is performed to a thickness of 10 to 300 μm (preferably 50 to 150 μm) using a known thermal spraying method such as a plasma spraying method. It is not necessary to cover the entire surface of the component with the sprayed material, and only the portion exposed to the plasma may be coated with the sprayed material. In addition, the surface of only the target shield, only the deposition-preventing plate, or only the target shield and the deposition-preventing plate may be coated with the sprayed material.

  In the present invention, a high-frequency power is applied in an atmosphere containing a rare gas to form a film by a sputtering method. For example, a silicon oxide film is formed by applying high-frequency power in an atmosphere containing oxygen or an oxygen and a rare gas, using silicon as a target and a shield covered with a sprayed material of silicon. The silicon nitride film is formed by applying high-frequency power to nitrogen or an atmosphere containing nitrogen and a rare gas, using silicon as a target and a shield covered with a sprayed material of silicon.

  In addition, since the target is silicon having a high specific resistance as compared with metal, it is desirable to apply a high-frequency power to generate and maintain a discharge at a low voltage, and a power frequency to be applied is 1 MHz or more and 120 MHz or less, preferably The frequency is 10 MHz to 60 MHz. As the frequency increases, the chemical reaction of the film formation mechanism becomes more preferential, and it is possible to expect the formation of a dense film with less damage to the base. The substrate 22 may be formed at a heating temperature of room temperature without heating. However, in order to further enhance the adhesion to the base, it is preferable that the substrate 22 is heated to 100 to 300 ° C., preferably 150 to 200 ° C. Adhesion is obtained.

  FIG. 2 shows a multi-chamber in which first to third film forming chambers 31 to 33, an unloading chamber 34 for unloading a substrate, and a load chamber 36 are arranged around a transfer chamber 35. The sputtering apparatus shown in FIG. 1 is arranged in any of the first to third film forming chambers 31 to 33. The film forming chambers 31 to 33, the unloading chamber 34, and the transfer chamber 35 are installed through transfer ports 40a to 40e. During film formation, the multi-chamber is maintained in a reduced pressure state.

  In this embodiment, a magnetron sputtering apparatus is described as an example, but the present invention is not limited to this, and may be applied to a sputtering apparatus using an ion beam sputtering method.

  Fe concentration in each of a silicon nitride film formed by using a sputtering apparatus having a shield sprayed with silicon of the present invention and a silicon nitride film formed by using a sputtering apparatus having a shield not sprayed with silicon 3 and 4 will be described with reference to FIGS.

In this experiment, silicon was sprayed only on the target shield so as to have a thickness of 60 to 80 μm. As the thermal spraying method, a method was used in which Ar, He, and H ₂ gas were flowed between the electrodes, a voltage was charged to generate plasma, and silicon powder was sprayed on the target shield. The surface roughness was Ra 3.5 to 4 μm and Rz 21 to 24 μm.

3 and 4 are graphs in which data points are connected by a smooth line. The horizontal axis is depth (μm), the left vertical axis is Fe concentration (atoms / cm ³ ), and the right vertical axis is secondary ion intensity of silicon. (Counts / sec). FIG. 3 shows the present invention with silicon spraying, and FIG. 4 shows no silicon spraying.

3 and 4, the Fe concentration is particularly significantly different in the depth range of 0 to 0.02 μm. That is, it can be seen that the concentration of Fe is lower in the silicon nitride film formed by using the sputtering apparatus of the present invention having the shield sprayed with silicon, and the effect of the present invention is particularly remarkable.
Therefore, when a thin film is formed using the sputtering apparatus of the present invention, the concentration of impurities in the thin film is reduced. Therefore, a high-quality thin film can be formed.

  The method for manufacturing a thin film of the present invention is applied to manufacturing of a liquid crystal display device or a display device using a light-emitting element. FIG. 5 shows, as an example, a display device using a light-emitting element to which the present invention is applied.

The TFT is provided in a pixel portion 302 and a driving circuit portion 301 formed in a peripheral portion thereof. As a semiconductor layer forming a channel formation region of a TFT, amorphous silicon, polycrystalline silicon, or the like can be selected, and any of the present invention may be employed.
The present invention is applied to formation of a semiconductor layer functioning as an active layer.

As the substrate 101, a glass substrate or an organic resin substrate is employed. The organic resin material is lighter in weight than the glass material, and effectively acts to reduce the weight of the light emitting device itself. As a material that can be used for manufacturing a light-emitting device, an organic resin material such as polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), or aramid can be used. As the glass substrate, barium borosilicate glass or aluminoborosilicate glass, which is called non-alkali glass, is desirably used. A glass substrate having a thickness of 0.5 to 1.1 mm is adopted, but it is necessary to reduce the thickness for the purpose of weight reduction. In order to further reduce the weight, it is desirable to use glass having a density as small as 2.37 g / cm ³ .

  In FIG. 5, an n-channel TFT 303 and a p-channel TFT 304 are formed in a driver circuit portion 301, and an n-channel first TFT 305, a p-channel fourth TFT 306, and a capacitor portion 307 are formed in a pixel portion 302. The fourth TFT 306 is connected to the anode layer 126 of the light emitting element 309.

These TFTs include semiconductor layers 103 to 106, a gate insulating film 108, and gate electrodes 110 to 113 on a first inorganic insulator layer 102 made of silicon nitride or silicon oxynitride. A second inorganic insulator layer 114 made of silicon nitride or silicon oxynitride containing hydrogen is formed over the gate electrode, and impurities such as moisture and metal are added to the semiconductor layer in combination with the first inorganic insulator layer 102. Is functioning as a protective film for preventing diffusion and contamination.
The present invention is applied to the formation of the first inorganic insulator layer 102 and the second inorganic insulator layer 102.

  On the second inorganic insulator layer 114, a first organic insulator layer 115 selected from polyimide, polyamide, polyimide amide, acrylic, and BCB is formed as a flattening film with a thickness of 0.5 to 1 μm. . The first organic insulator layer 115 is formed by applying the organic compound by a spin coating method and then firing. Organic insulator materials are hygroscopic and have the property of absorbing moisture. When the moisture is re-emitted, oxygen is supplied to the organic compound of the light emitting element formed in the upper layer, which causes deterioration of the organic light emitting element. In order to prevent occlusion and re-release of moisture, a third inorganic insulator layer 116 is formed on the first organic insulator layer 115 to a thickness of 50 to 200 nm. The third inorganic insulator layer 116 needs to be a dense film from the viewpoint of adhesion to the base and barrier properties, and is preferably formed by a sputtering method such as silicon nitride, silicon oxynitride, aluminum oxynitride, and aluminum nitride. Formed of an inorganic insulating material selected from the group consisting of:

The organic light emitting element 309 is formed on the third inorganic insulator layer 116. In a light-emitting device that emits light emitted through the substrate 101, an ITO (indium tin oxide) layer is formed as the anode layer 126 over the third inorganic insulator layer 116. Zinc oxide or gallium may be added to ITO for the purpose of planarization and low resistance. The wirings 117 to 125 are formed before the anode layer 126 and are overlapped on the third inorganic insulator layer 116 to form an electrical connection.
The present invention is applied to the formation of the third inorganic insulator layer 116.

  The second organic insulator layer (partition layer) 128 for separating each pixel is formed of a material selected from polyimide, polyamide, polyimide amide, acrylic, and benzocyclobutene (BCB). For these, a thermosetting or photocurable material can be applied. The second organic insulator layer (partition layer) 128 is formed by forming the organic insulator material over the entire surface to a thickness of 0.5 to 2 μm, and then forming an opening corresponding to the anode layer 126. In this case, the anode layer 126 is formed so as to cover the end, and the inclination angle of the side wall is 35 to 45 degrees. The second organic insulator layer (partition layer) 128 is formed so as to extend not only over the pixel portion 302 but also over the drive circuit portion 301, and functions as an interlayer insulating film when formed over the wirings 117 to 124. It also has.

  Organic insulator materials are hygroscopic and have the property of absorbing moisture. When the water is released again, the water is supplied to the organic compound of the light emitting element 309 to cause deterioration of the organic light emitting element. In order to prevent occlusion and re-release of moisture, a fourth inorganic insulator layer 129 is formed on the second organic insulator layer 128 to a thickness of 10 to 100 nm. The fourth inorganic insulator layer 129 is formed using an inorganic insulator material made of nitride. Specifically, it is formed using an inorganic insulating material selected from silicon nitride, aluminum nitride, and aluminum nitride oxide. The fourth inorganic insulator layer 129 is formed so as to cover the upper surface and side surfaces of the second organic insulator layer 128, and is formed so that the end overlapping the anode layer 126 has a tapered shape.

  The organic light-emitting element 309 includes an anode layer 126, a cathode layer 131 containing an alkali metal or an alkaline earth metal, and an organic compound layer 130 containing a light-emitting body formed therebetween. The organic compound layer 130 including the light emitting body is formed by laminating one or more layers. Each layer is referred to as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, or the like, depending on its purpose and function. These can be formed from any of a low molecular weight organic compound material, a medium molecular weight organic compound material, and a high molecular weight organic compound material, or a suitable combination of both. Further, a mixed layer in which an electron transporting material and a hole transporting material are appropriately mixed, or a mixed junction in which a mixed region is formed at each bonding interface may be formed.

  The cathode layer 131 is formed of an alkali metal or an alkaline earth metal having a small work function, and uses a material containing magnesium (Mg), lithium (Li), or calcium (Ca). Preferably, an electrode made of MgAg (a material in which Mg and Ag are mixed at a ratio of Mg: Ag = 10: 1) may be used. Other examples include a MgAgAl electrode, a LiAl electrode, and a LiFAl electrode. Alternatively, it may be formed by combining a fluoride of an alkali metal or an alkaline earth metal with a low-resistance metal such as aluminum. The cathode layer 131 is formed as a common electrode over a plurality of pixels, is connected to the wiring 120 outside the pixel portion 302 or between the pixel portion 302 and the driving circuit portion 301, and is led to an external terminal.

Further, as the upper layer, the fifth inorganic insulator layer 132 may be formed of a material selected from silicon nitride, diamond-like carbon (DLC), aluminum oxynitride, aluminum oxide, aluminum nitride, and the like. In particular, it is known that DLC films have high gas barrier properties against oxygen, CO, CO ₂ , H ₂ O, and the like. After the cathode 131 is formed, the fifth inorganic insulator layer 132 is preferably formed continuously without opening to the atmosphere. A buffer layer of silicon nitride may be provided below the fifth inorganic insulator layer 132 to improve adhesion.

  Although not shown, a sixth inorganic insulator layer may be formed at the interface between the anode layer 126 and the organic compound layer 130 including the luminous body with a thickness of 0.5 to 5 nm and a thickness such that a tunnel current flows. . This has an effect of preventing a short circuit due to unevenness on the surface of the anode and suppressing diffusion of an alkali metal or the like used for the cathode to the lower layer side.

  The second organic insulator layer 128 formed in the pixel portion 302 extends on the drive circuit portion 301, and the seal pattern 133 is formed on the fourth inorganic insulator layer 129 formed on the second organic insulator layer 128. It is formed. The seal pattern 133 is provided so as to partially or entirely overlap the driving circuit portion 301 and the wiring 117 connecting the driving circuit portion 301 to an input terminal, and reduces the area of a frame region (a peripheral region of a pixel portion) of the light-emitting device. Has been reduced.

  The sealing plate 134 is fixed via the seal pattern 133. Metal such as stainless steel or aluminum can be used for the sealing plate 134. Further, a glass substrate or the like may be used. A desiccant 135 such as barium oxide is sealed in the inside surrounded by the seal pattern 133 and the sealing plate 134 to prevent deterioration due to moisture. The thickness of the sealing plate may be made flexible by using an organic resin material having a thickness of about 30 to 120 μm. A film made of an inorganic insulator such as DLC or silicon nitride may be formed on the surface as a gas barrier layer. An example of a material used for the seal pattern is an epoxy-based adhesive. By covering the side surface with a coating made of an inorganic insulator, it is possible to prevent water vapor permeating from that portion.

  The input terminal portion 308 is formed using a wiring formed in the same layer as the gate electrode or a wiring formed over the third inorganic insulating layer 116. FIG. 5 shows an example in which the gate electrode is formed using the same layer as the gate electrode, which is formed using the conductive layers 109 and 127. The conductive layer 127 is formed at the same time as the anode layer 126, and is formed of an oxide conductive material. In practice, by covering the portion exposed on the surface with this oxide conductive material, an increase in surface resistance due to an oxidation reaction is prevented.

  As shown in FIG. 5, a first inorganic insulator layer 102 and a second inorganic insulator layer 114 are formed so as to surround the semiconductor layers 105 and 106. On the other hand, the organic light-emitting element 309 is surrounded by the third inorganic insulator layer 116, the fifth inorganic insulator layer 132, and the fourth inorganic insulator layer 129. That is, the semiconductor layer and the light emitting element of the TFT have a structure in which they are respectively covered with the inorganic insulator layer. The inorganic insulator layer is a silicon nitride or silicon oxynitride film, and uses a material having a barrier property against water vapor and ionic impurities.

  The substrate 101 and the organic light emitting element 309 can be considered as a source of contamination of the first TFT 305 and the fourth TFT 306 with an alkali metal such as sodium. Can be. On the other hand, since the organic light emitting element 309 dislikes oxygen and moisture most, the third inorganic insulator layer 116, the fourth inorganic insulator layer 129, and the fifth inorganic insulator layer 132 are formed of an inorganic insulator material in order to prevent them. It prevents that pollution. These also have a function of keeping the alkali metal element included in the organic light-emitting element 309 from outside.

  As described above, the present invention is applied to formation of a semiconductor layer functioning as an active layer and an inorganic insulator layer. By applying the present invention, a high-quality thin film can be formed with high yield, and the productivity of an element using the thin film can be improved. Therefore, the productivity of a display device using the above element can be improved.

The figure which shows the sputtering device of this invention. The figure which shows a multi-chamber. The figure which shows experimental data. The figure which shows experimental data. 1 is a cross-sectional view of a display device to which the present invention is applied.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 ... Gas introduction means, 11 ... Substrate holding means, 12 ... Heating means, 13 ... Back plate, 14 ... Shutter, 15 ... Gate valve, 16 ... Deposition plate , 17 ... Target shield, 18 ... Permanent magnet, 19 ... Target, 20 ... Conductance valve, 21 ... Rectifier plate, 22 ... Substrate, 23 ... Sprayed material

Claims (13)

  A sputtering apparatus comprising: a target material; and a component coated with a sprayed material of the same material as the target material.   A sputtering apparatus, comprising: a semiconductor material as a target material; and a component coated with a sprayed material of the semiconductor material.   A sputtering apparatus, comprising: a component which is made of a semiconductor material as a target material and is coated with a sprayed material which is an oxide or a nitride of the semiconductor material. A target material, comprising a part coated with a sprayed material of the same material as the target material,
The thin film formed on the substrate provided opposite to the target material is the same material as the sprayed material, or an oxide of the sprayed material, or a nitride of the sprayed material, the sputtering apparatus . Using a semiconductor material as a target material, comprising a part coated with a sprayed material of the semiconductor material,
The thin film formed on the substrate provided opposite to the target material is the same material as the semiconductor material, or an oxide of the semiconductor material, or a nitride of the semiconductor material. . Using a semiconductor material as a target material, comprising a component coated with a spray that is an oxide or nitride of the semiconductor material,
A sputtering apparatus, wherein a thin film formed on a substrate provided opposite to the target material is an oxide of the semiconductor material or a nitride of the semiconductor material.   7. The sputtering apparatus according to claim 1, wherein the component is a target shield, a deposition-preventing plate, a backing plate, a rectifying plate, a substrate holder, a gas introduction pipe, or an inner wall of a chamber. .   7. The sputtering apparatus according to claim 2, wherein the semiconductor material is silicon. In a method for producing a thin film using a sputtering apparatus having a target material and a component coated with a sprayed material of the same material as the target material,
Applying high-frequency power in an atmosphere containing a rare gas to produce a thin film made of the same material as the target material, or an oxide of the target material, or a nitride of the target material. Method. A method for producing a thin film using a sputtering device having a semiconductor material as a target material and a component coated with a sprayed material of the same material as the semiconductor material,
A method for producing a thin film, comprising applying a high-frequency power in an atmosphere containing a rare gas to produce a thin film made of the semiconductor material, the oxide of the semiconductor material, or the nitride of the semiconductor material. A method for producing a thin film using a sputtering device having a semiconductor material as a target material and a component coated with a thermal spray that is an oxide or nitride of the semiconductor material,
A method for producing a thin film, comprising applying a high-frequency power in an atmosphere containing a rare gas to produce a thin film made of an oxide of the semiconductor material or a nitride of the semiconductor material.   The thin film according to any one of claims 9 to 11, wherein the component is a target shield, a deposition-preventing plate, a backing plate, a rectifying plate, a substrate holder, a gas introduction pipe, or an inner wall of a chamber. Production method. 12. The method according to claim 10, wherein the semiconductor material is silicon.

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