Film forming apparatus for forming a film by sputtering through inductively coupled plasma

Abstract

A film forming apparatus includes a film forming chamber in which a sputtering target is installed, a plasma diffusion prevention plate that covers the sputtering target and has an opening at a position overlapping the surface of the sputtering target, an antenna for discharging that is disposed adjacent to the sputtering target and protrudes inward into the region surrounded by the plasma diffusion prevention plate, and a gas introduction pipe that is disposed inside the plasma diffusion prevention plate and introduces gas into the film forming chamber. The antenna includes an insulating member having a U-shaped groove shape that protrudes inward of the plasma diffusion prevention plate, and an antenna body disposed on the atmosphere side of the insulating member, wherein the antenna body can protrude inward of the film forming chamber from the surface of the sputtering target.

Description

Technical Field

[0001] One embodiment of the present invention relates to a film forming apparatus using inductively coupled plasma (ICP). Background Art

[0002] Sputtering is a physical vapor deposition method (PVD) for forming a thin film. As is well known, sputtering is a technique in which plasma is generated in a vacuum, ions in the plasma collide with a sputtering target at high speed, thereby generating sputtering, and particles (atoms or molecules) of a film forming material constituting the target are deposited on the surface of a substrate to form a thin film.

[0003] As a sputtering apparatus, a magnetron method in which a magnetron is disposed on the back surface of a sputtering target is well known. In addition, a sputtering apparatus using inductively coupled plasma (ICP) has also been disclosed (for example, see Patent Document 1). An antenna structure for generating inductively coupled plasma has also been disclosed (see Patent Document 2).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-065299

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2016-072168 Summary of the Invention

[0008] Technical Problem to be Solved by the Invention

[0009] In the magnetron sputtering method, since the magnetic field (magnetic field intensity) generated by the magnet is non-uniform, the erosion of the sputtering target is non-uniform. Therefore, there are problems such as low effective utilization rate of the target material and easy generation of nodules. In addition, since the magnetic field concentrates the plasma locally, the target material is easily subjected to thermal stress, and there is a problem that cracks are easily generated in the target material.

[0010] In addition, when forming a metal film by magnetron sputtering, if the magnetic field intensity generated by the magnet is strong, densification of the deposited film can be achieved. However, when forming an oxide material film (for example, an oxide semiconductor film and an oxide conductive film), oxygen is decomposed only in a region where the magnetic field intensity is strong near the sputtering target, and unreacted oxygen molecules (O2) are adsorbed on the deposition surface and absorbed into the film in the state of oxygen molecules, resulting in a problem of a decrease in the density of the deposited film.

[0011] In addition, in a conventional sputtering apparatus using inductively coupled plasma (ICP), in order to efficiently generate inductively coupled plasma, an antenna body and an insulating cylinder tube covering the antenna are arranged inside the film formation chamber. However, in the case of dealing with large-scale film formation chambers larger than 3 meters, it becomes very difficult to stably hold the antenna body and the insulating cylinder tube covering the antenna.

[0012] In addition, in the inductively coupled plasma (ICP) sputtering apparatus disclosed in Patent Document 1, the generated inductively coupled plasma diffuses throughout the inside of the film formation chamber, and the plasma cannot be confined near the sputtering target like in a magnetron sputtering apparatus. Therefore, compared with a magnetron sputtering apparatus, there is a fundamental problem that moisture (H2O), oxygen (O2), and hydrocarbons adsorbed on the inner wall of the film formation chamber are largely detached from the inner wall of the film formation chamber at the start of film formation and easily enter the coating being formed. In order to increase the plasma density near the sputtering target, only the current flowing to the antenna body can be increased, which instead increases the amount of contaminant gas detached from the inner wall of the film formation chamber and becomes the main cause of the reduction in the reproducibility of the film quality of the deposited film.

[0013] In view of these problems, an object of one embodiment of the present invention is to provide a film formation method and apparatus capable of forming a high-quality thin film with good reproducibility and high efficiency in film formation by sputtering.

[0014] Means for Solving the Problem

[0015] The film formation apparatus according to one embodiment of the present invention includes: a film formation chamber provided with a sputtering target, a plasma diffusion prevention plate covering the sputtering target and having an opening at a position overlapping the surface of the sputtering target, an antenna for generating inductively coupled plasma provided adjacent to the sputtering target and protruding inwardly into the region surrounded by the plasma diffusion prevention plate, and a gas introduction tube provided inside the plasma diffusion prevention plate and for introducing gas into the film formation chamber, wherein a negative pulse voltage is applied to the sputtering target.

[0016] Effects of the Invention

[0017] According to one embodiment of the present invention, a plasma diffusion prevention plate is provided to cover the antenna for generating inductively coupled plasma and the sputtering target, so that the inductively coupled plasma can be prevented from diffusing in the entire internal space of the film formation chamber, and impurities can be prevented from entering the formed thin film. In addition, since the plasma density near the sputtering target can be increased, the sputtering rate can also be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Shows the overall structure of the film formation apparatus according to one embodiment of the present invention.

[0019] Figure 2The figure showing the structure of the film forming apparatus according to an embodiment of the present invention shows the main components provided or connected to the pretreatment chamber, transfer chamber, and film forming chamber other than the loading / unloading chamber.

[0020] Figure 3 The partial cross-sectional schematic view shows the film forming chamber of the film forming apparatus according to an embodiment of the present invention when viewed from the upper surface.

[0021] Figure 4 The detailed cross-sectional structure of the antenna used for generating inductively coupled plasma in the film forming apparatus according to an embodiment of the present invention is shown.

[0022] Figure 5 The detailed cross-sectional structure of the antenna used for generating inductively coupled plasma in the film forming apparatus according to an embodiment of the present invention is shown.

[0023] Figure 6 The schematic view shows the plasma diffusion prevention plate provided in the film forming chamber of the film forming apparatus according to an embodiment of the present invention when viewed from the front.

[0024] Figure 7 The schematic view shows the plasma diffusion prevention plate provided in the film forming chamber of the film forming apparatus according to an embodiment of the present invention when viewed from the front.

[0025] Figure 8A The figure is for explaining the influence of the antenna for generating inductively coupled plasma provided in the film forming chamber on the substrate surface, showing the case without the plasma diffusion prevention plate.

[0026] Figure 8B The figure is for explaining the influence of the antenna for generating inductively coupled plasma provided in the film forming chamber on the substrate surface, showing the case with the plasma diffusion prevention plate.

[0027] Figure 9 The figure is for explaining the influence of the antenna for generating inductively coupled plasma provided in the film forming chamber on the substrate surface, and is a figure for explaining the problem of uneven deposition film that may occur in the case without the plasma diffusion prevention plate.

[0028] Figure 10A The example of the film forming target installed on the film forming apparatus according to an embodiment of the present invention is shown, and the case of using two target materials is shown.

[0029] Figure 10B The example of the film forming target installed on the film forming apparatus according to an embodiment of the present invention is shown, and the case of using three target materials is shown.

[0030] Figure 11A diagram showing the structure of an antenna for generating inductively coupled plasma disposed in a film formation chamber of a film formation apparatus according to an embodiment of the present invention.

[0031] Figure 12 A cross-sectional structure of an antenna connection region of an antenna body of an antenna for generating inductively coupled plasma used in a film formation apparatus according to an embodiment of the present invention is shown.

[0032] Figure 13 A diagram showing waveforms of an alternating current voltage applied to an antenna for generating inductively coupled plasma disposed in a film formation chamber of a film formation apparatus according to an embodiment of the present invention and a pulse voltage applied to a film formation target.

[0033] Figure 14 The mode shows the relationship between the target voltage and the film density when forming an InGaZnO film as an oxide semiconductor film.

[0034] Figure 15 A cross-sectional schematic diagram showing the structure of a pretreatment chamber of a film formation apparatus according to an embodiment of the present invention is shown.

[0035] Figure 16A A front view of an antenna for generating inductively coupled plasma disposed in a film formation chamber of a film formation apparatus according to an embodiment of the present invention is shown.

[0036] Figure 16B A cross-sectional view of an antenna for generating inductively coupled plasma disposed in a film formation chamber of a film formation apparatus according to an embodiment of the present invention is shown, and the cross-sectional structure corresponding to that between A1 - A2 shown is shown. Figure 16A The cross-sectional structure between A1 - A2 shown is shown.

[0037] Figure 17A A front view of an antenna for generating inductively coupled plasma disposed in a film formation chamber of a film formation apparatus according to an embodiment of the present invention is shown.

[0038] Figure 17B A cross-sectional view of an antenna for generating inductively coupled plasma disposed in a film formation chamber of a film formation apparatus according to an embodiment of the present invention is shown, and the cross-sectional structure corresponding to that between B1 - B2 shown is shown. Figure 17A The cross-sectional structure between B1 - B2 shown is shown.

[0039] Figure 18A An example of an element manufactured using a film formation apparatus according to an embodiment of the present invention is shown.

[0040] Figure 18B A detailed structure of an oxide semiconductor layer in an element manufactured using a film formation apparatus according to an embodiment of the present invention is shown.

[0041] Figure 18C Shows the detailed structure of the oxide semiconductor layer in an element manufactured using the film forming apparatus according to an embodiment of the present invention.

[0042] Figure 19 Shows the overall structure of the film forming apparatus according to an embodiment of the present invention.

[0043] Figure 20 It is a diagram showing the structure of the film forming apparatus according to an embodiment of the present invention, and shows the main components provided or connected to the pretreatment chamber, transfer chamber, and film forming chamber other than the loading / unloading chamber.

[0044] Figure 21 Shows an example of an element manufactured using the film forming apparatus according to an embodiment of the present invention.

[0045] Figure 22A Shows a partial cross-sectional schematic view when the film forming chamber of the film forming apparatus according to an embodiment of the present invention is viewed from the upper surface.

[0046] Figure 22B Shows for Figure 22A A front view of the ceramic component of the film forming chamber shown.

[0047] Figure 23A Shows a partial cross-sectional schematic view when the film forming chamber of the film forming apparatus according to an embodiment of the present invention is viewed from the upper surface.

[0048] Figure 23B Shows for Figure 23A A front view of the ceramic component of the film forming chamber shown. Detailed embodiments

[0049] Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. However, the present invention includes many different aspects and is not limited to the embodiments described in the following examples. For clearer explanation, the attached drawings in this specification may schematically show the width, thickness, shape, etc. of each part compared to the actual way, but this is only an example and does not necessarily limit the content of the present invention. In addition, in the present invention, when a specific element described in one drawing has the same or corresponding relationship with a specific element described in another drawing, the same symbol (or a symbol such as a, b, etc. added after the number described as a symbol) can be used to mark it, and repeated explanations are appropriately omitted. In addition, the words "first" and "second" attached to each element are convenient signs for distinguishing each element and have no more meaning unless otherwise specified.

[0050] In this specification, when a member or region is "above (or below)" another member or region, unless otherwise specifically restricted, this includes not only the case where it is directly above (or directly below) another member or region, but also the case where it is above (or below) another member or region. It also includes the case where another component is included between a member or region above (or below) another member or region and a certain member or region.

[0051] First Embodiment

[0052] Figure 1 The overall structure of a film forming apparatus 100 for performing sputtering film formation according to an embodiment of the present invention is shown. The film forming apparatus 100 includes a load / unload chamber 102 for accommodating a substrate before and after film formation, a pretreatment chamber 104 for performing pretreatment of the substrate, a first transfer chamber 106a provided with a transfer robot 116, a second transfer chamber 106b provided with a chuck mechanism 118, a first film forming chamber 108a and a second film forming chamber 108b for performing sputtering film formation. These chambers are connected by gate valves, and a vacuum exhaust device (not shown) is provided.

[0053] The substrate on which a thin film is to be formed is stored in the load / unload chamber 102 while being held in a cassette. The substrate is, for example, a glass substrate. The substrate accommodated in the load / unload chamber 106 is transferred to the pretreatment chamber 104 by the transfer robot 116 provided on the first transfer chamber 102a. The pretreatment chamber 104 performs pretreatment on the substrate on which a thin film is to be formed. The pretreatment chamber 104 includes a high-frequency discharge electrode connected to a high-frequency power supply 120. As pretreatment, the substrate is degassed by a stage provided with a heating mechanism and high-frequency discharge plasma generated by the high-frequency discharge electrode. Figure 1 The state where two pretreatment chambers 104 are provided across the first transfer chamber 106a is shown, but the number of pretreatment chambers 104 is not limited. As Figure 1 shown, when two pretreatment chambers 104 are provided in the film forming apparatus 100, sputtering film formation can be continuously performed with sufficient time while sufficiently performing degassing treatment. In addition, the film forming apparatus 100 is not limited to Figure 1 the form shown, and the number of pretreatment chambers 104 can be one, or three or more.

[0054] The substrate pretreated by the pretreatment chamber 104 is transferred to the second transfer chamber 106b by the transfer robot 116. The substrate is transferred from the load / unload chamber 102 to the pretreatment chamber 104 in a horizontal state. The second transfer chamber 106b is provided with a chuck mechanism 118, and the substrate carried in in a horizontal state is Figure 1 held by a transfer carrier (not shown) in the form of being erected in a vertical state or in a state within a range of about 20 degrees from the vertical.

[0055] The first film forming chamber 108a and the second film forming chamber 108b are provided with an antenna 126 for generating inductively coupled plasma, and a sputtering target 124 is installed. In the first film forming chamber 108a and the second film forming chamber 108b, sputtering film formation is performed by inductively coupled plasma (ICP) generated by the antenna 126 for generating inductively coupled plasma. A pulse power supply 123 is connected to the sputtering target 124, and the acceleration energy of ions can be controlled. In the film forming apparatus 100, the density of the thin film deposited on the substrate can be controlled by such a mechanism.

[0056] In the first film forming chamber 108a and the second film forming chamber 108b, sputtering targets 124 of different materials (composition, constitution, density) can be installed, and thin films of different compositions can be continuously deposited in a vacuum. In addition, in the first film forming chamber 108a and the second film forming chamber 108b, sputtering targets 124 of the same kind (composition, constitution, density) can be installed, so that different film forming conditions can be applied to deposit thin films of different film qualities. Figure 1 Two film forming chambers 108 are shown, but the film forming apparatus 100 is not limited to such a structure, and the number of film forming chambers 108 can be appropriately changed according to the structure and type of the thin film to be produced. For example, in the case of forming a single-layer thin film in the film forming apparatus 100, the number of film forming chambers 108 can be one, and in the case of forming a multi-layer thin film, three or more film forming chambers 108 can also be connected.

[0057] Figure 2 The figure showing the structure of the film forming apparatus 100 shows the main components provided or connected to the pretreatment chamber 104, the first transfer chamber 106a, the second transfer chamber 106b, the first film forming chamber 108a, and the second film forming chamber 108b other than the loading / unloading chamber. A vacuum exhaust system 110 is connected to each chamber. The vacuum exhaust system 110 is composed of vacuum pumps such as a turbo molecular pump (TMP) and a dry pump (DRP). The structures of the vacuum exhaust systems 110 of the first transfer chamber 106a and the second transfer chamber 106b and the first film forming chamber 108a and the second film forming chamber 108b may be different or the same. In the first film forming chamber 108a and the second film forming chamber 108b, a conduction valve for pressure control can be provided. In addition, a gas supply system 112 is connected to the pretreatment chamber 104, the first film forming chamber 108a, and the second film forming chamber 108b. The gas supply system 112 is composed of a mass flow controller, a filter, and the like.

[0058] The pretreatment chamber 104 is provided with a substrate stage 114 and a high-frequency discharge electrode 115. The high-frequency discharge electrode 115 is connected to a high-frequency power supply 120. In the pretreatment chamber 104, pretreatment of the substrate is performed by high-frequency discharge plasma generated by the substrate stage 114 and the high-frequency discharge electrode 115.

[0059] Between the pretreatment chamber 104 and the first film forming chamber 108a, the apparatus is provided with a first transfer chamber 106a for a transfer robot 116 and a second transfer chamber 106b for a chuck mechanism 118. The substrate that has undergone the desorption process of adsorbed molecules in the pretreatment chamber 104 is not in contact with the atmosphere and is transferred to the first film forming chamber 108a via the first transfer chamber 106a and the second transfer chamber 106b. The substrate pretreated by the pretreatment chamber 104 is transferred to the second transfer chamber 106b by the transfer robot 116 in the first transfer chamber 106a. The transfer robot 116 transfers the substrate while maintaining the substrate in a horizontal state. The substrate transferred to the second transfer chamber 106b is erected by the chuck mechanism 118 in a vertical state or inclined within a range of about 20 degrees from the vertical direction and is transferred to the first film forming chamber 108a.

[0060] It is generally considered that film formation by sputtering is preferably carried out with the substrate erected rather than in a horizontal state to avoid forming pinholes in the deposited film. However, for example, in the case of display applications, as the substrate size increases (for example, the eighth-generation glass substrate for the liquid crystal process is 2200 mm × 2400 mm), it bends due to its own weight, so it is difficult to always transfer the substrate in a vertically erected state. In addition, in a film forming apparatus such as a cluster single-wafer sputtering apparatus that forms a film while maintaining the substrate in a horizontal state, as the substrate size increases, the floor area of the apparatus increases (that is, the floor area of the clean room increases), which is a problem. In view of such problems, the film forming apparatus 100 is provided with a chuck mechanism 118 in the middle of the substrate transfer path, so that the substrate is horizontally processed until the early stage of film formation, and the substrate is erected in a vertical state or within a range inclined about 20 degrees from the vertical during the film formation stage, so that the substrate processing becomes easy. In addition, the film forming apparatus 100 has the advantage of being able to reduce the floor area required for installation.

[0061] The first film forming chamber 108a is provided with an antenna 126 for generating inductively coupled plasma and a sputtering target 124 is installed. The antenna 126 for generating inductively coupled plasma is connected to a high-frequency power supply 120 that outputs high frequency in the megahertz band. In addition, an AC power supply 122 can be connected so that an AC voltage in the kilohertz band can be applied, so that the antenna 126 for generating inductively coupled plasma overlaps with the high-frequency power. The pulse power supply 123 is connected to the sputtering target 124 as described above. In the first film forming chamber 108a, a heater 127 for heating the substrate may also be provided.

[0062] Although the detailed description is omitted, the second film forming chamber 108b also has the same structure as the first film forming chamber 108a. Although not shown in Figure 2 , a transfer mechanism for transporting the substrate in a vertical state or within a range inclined 20 degrees from the vertical is provided in the first film forming chamber 108a and the second film forming chamber 108b.

[0063] Figure 3 This is a schematic cross-sectional view of a partial section when the film-forming chamber 108 (the first film-forming chamber 108a and the second film-forming chamber 108b) is observed from the upper surface. The film-forming chamber 108 is configured to form a closed space with an internal space isolated from the atmosphere. Figure 3 It shows a schematic structure between two wall surfaces (the first chamber wall 109a and the second chamber wall 109b).

[0064] The film-forming chamber 108 includes a plasma diffusion prevention plate 140 provided to cover the sputtering target 124, an antenna 126 (the first antenna 126a and the second antenna 126b) for generating inductively coupled plasma provided so as to protrude into the region surrounded by the plasma diffusion prevention plate 140, and a gas introduction pipe 138 for introducing a sputtering gas. The film-forming apparatus 100 is used in a state where the sputtering target 124 is installed in the film-forming chamber 108. However, the sputtering target 124 can be said to be a consumable item, not a constituent component fixed to the film-forming apparatus 100, but an accessory component that is appropriately replaced. Although components such as the sputtering target 124 and the antenna 126 for generating inductively coupled plasma are attached to the film-forming chamber 108, sealing components such as O-rings and gaskets are attached to the attachment portions of each component.

[0065] The sputtering target 124 includes a target material 132 and a backing plate 130. The target material 132 is joined to the backing plate 130 formed of a metal such as copper (Cu), titanium (Ti), etc. using a joining material such as an indium alloy. The target material 132 is preferably an integrally formed product. The sputtering target 124 is installed on the first chamber wall 109a of the film-forming chamber 108. A first through-hole 128a is provided in the first chamber wall 109a, and the sputtering target 124 is installed in such a manner that the backing plate 130 is inserted into the first through-hole 128a. In order to apply a bias voltage to the sputtering target 124, an insulating member 136 is provided between the backing plate 130 and the first chamber wall 109a.

[0066] When viewed from the front, the sputtering target 124 is rectangular and the length direction is parallel to the vertical direction. The target material 132 can be installed with various sputterable materials. For example, as the target material 132, a sintered body of a metal oxide for forming a transparent conductive film and an oxide semiconductor film can be applied. The temperature of the target material 132 rises due to ion collisions during sputter film formation. Therefore, the film-forming apparatus 100 is provided with a mechanism for cooling the backing plate 130 to suppress the temperature rise of the target material 132. As an example thereof, Figure 3 It shows a structure in which a water flow hole for flowing cooling water is provided in the backing plate 130.

[0067] When the sputtering target 124 is mounted on the first chamber wall 109a, the target material 132 is exposed to the internal space of the film formation chamber 108. The film formation chamber 108 is provided with a shielding plate 134 to cover the peripheral portion of the target material 132. The shielding plate 134 covers the surface of the backing plate 130 in the region exposed between the target material 132 and the first chamber wall 109a. With this structure, the backing plate 130 can be protected from being sputtered due to exposure to inductively coupled plasma.

[0068] The film formation chamber 108 is provided with an antenna 126 (first antenna 126a, second antenna 126b) for generating inductively coupled plasma. The antenna 126 for generating inductively coupled plasma is configured to sandwich the sputtering target 124 along the longitudinal direction of the sputtering target 124. That is, the first antenna 126a and the second antenna 126b, which are the antennas 126 for generating inductively coupled plasma, are configured to sandwich the sputtering target 124.

[0069] The first antenna 126a and the second antenna 126b, which are the antennas 126 for generating inductively coupled plasma, include an antenna body 148 (first antenna body 148a, second antenna body 148b) for generating inductively coupled plasma and insulating members 146 (first insulating member 146a, second insulating member 146b) formed in a U-shaped groove shape. The first antenna body 148a is disposed in the first insulating member 146a, and the second antenna body 148b is disposed in the second insulating member 146b. The antenna 126 for generating inductively coupled plasma is disposed such that the insulating member 146 is inserted into the second through hole 128b of the first chamber wall 109a and protrudes to both sides of the sputtering target 124. In this way, by disposing the antenna body 148 for generating inductively coupled plasma in the insulating member 146, it is possible to prevent the material sputtered from the target material 132 from adhering to the antenna body 148 for generating inductively coupled plasma. In addition, the antenna body 148 for generating inductively coupled plasma can be prevented from being exposed to inductively coupled plasma.

[0070] The antenna 126 for generating inductively coupled plasma is disposed such that the antenna body 148 for generating inductively coupled plasma protrudes to a position higher than the surface of the target material 132 (a position closer to the center in the film formation chamber 108 or a position on the substrate 200 side). For example, the antenna body 148 for generating inductively coupled plasma is disposed to protrude a length D2 from the surface of the target material 132. As described above, by protruding the antenna body 148 for generating inductively coupled plasma from the surface of the target material 132, the plasma density at the surface of the target material 132 can be increased.

[0071] Figure 22A Another structure of the film formation chamber 108 (first film formation chamber 108a, second film formation chamber 108b) is shown. Figure 22AShows a partial cross-sectional schematic view when observing the film deposition chamber 108 from above in the same way. Figure 3 The structure of the film deposition chamber 108 shown is such that a part of the first chamber wall 109a on which the antenna 126 (first antenna 126a, second antenna 126b) for generating inductively coupled plasma and the sputtering target 124 are installed is formed of a ceramic component 180a. Figure 22A Shows a front view of the ceramic component 180a. Figure 22B

[0072] As Figure 22A and Figure 22B shown, a first through hole 128a for installing the sputtering target 124 is provided in the ceramic component 180a. Since the ceramic component 180a has insulating properties, the sputtering target 124 can be directly installed. That is, when the sputtering target 124 is installed in the film deposition chamber 108, the insulating component 136 shown in Figure 3 can be omitted. In addition, a second through hole 128b for installing the antenna 126 (first antenna 126a, second antenna 126b) for generating inductively coupled plasma is provided in the ceramic component 180a. The U-shaped groove-shaped insulating component 146 (first insulating component 146a, second insulating component 146b) is inserted from the second through hole 128b and vacuum-sealed on the back side of the ceramic component 180a by an O-ring. Furthermore, since the ceramic component 180a is insulating, the shielding plate 134 covering the peripheral portion of the target 132 can be integrated.

[0073] Figure 23A Shows a structure in the film deposition chamber 108 (first film deposition chamber 108a, second film deposition chamber 108b) where a part of the first chamber wall 109a is integrated with a U-shaped groove-shaped insulating component 146 (first insulating component 146a, second insulating component 146b) covering the antenna body 148 (first antenna body 148a, second antenna body 148b) for generating inductively coupled plasma on the ceramic component 180b. Figure 23B Also shows a front view of the ceramic component 180b. As Figure 23A and Figure 23B shown, by integrally forming the U-shaped groove-shaped insulating component 146 (first insulating component 146a, second insulating component 146b) with a part of the first chamber wall 109a, the number of components can be reduced and leakage (vacuum airtight leakage) can be prevented. A glass layer can also be formed on the atmosphere side (the side where the antenna body 148 for generating inductively coupled plasma is provided) of the ceramic component 180b corresponding to the part formed as the U-shaped groove-shaped insulating component (first insulating component 146a, second insulating component 146b). The setting of the glass layer can further reduce leakage from the atmosphere side.

[0074] ​The ceramic components 180a and 180b not only have excellent insulation properties, but also have a high heat-resistant temperature, a small coefficient of thermal expansion, can be precisely machined, and have a small gas release amount. Therefore, they can be suitably used as the wall material of the film formation chamber 108. By using the ceramic components 180a and 180b as the wall material near the antenna 126 for generating inductively coupled plasma, the power loss of the antenna 126 for generating inductively coupled plasma can be reduced. As a result, the plasma density near the surface of the target 132 can be increased.

[0075] As Figure 22A and Figure 23A shown, by forming the first chamber wall 109a on which the sputtering target 124 is mounted with the ceramic components 180a and 180b, the outgassing amount from the inner wall of the chamber can be reduced and the plasma density can be increased. In addition, since the peripheral portion of the target 132 is composed of the ceramic components 180a and 180b as insulating components, the generation region of the vertical electric field with respect to the surface of the target 132 can be expanded, and thus a film with a higher density can be manufactured.

[0076] Figure 4 The detailed cross-sectional structure of the antenna 126 for generating inductively coupled plasma is shown. The antenna body 148 for generating inductively coupled plasma is formed by a hollow metal tube 150. For example, the antenna body 148 for generating inductively coupled plasma is formed by a hollow metal tube 150 such as copper (Cu), brass, or aluminum (Al). The antenna body 148 for generating inductively coupled plasma is formed into a rod-shaped antenna by such a metal tube, and a cooling water flow passes through the hollow portion. A conductive layer 151 formed by a coating film of nickel (Ni) or tin (Sn) is preferably formed on the inner surface of the metal tube 150 to prevent corrosion. The insulating member 146 is made of ceramics such as quartz, alumina, yttrium oxide (Y2O3), forsterite (Mg2SiO4), or talc (MgO·SiO2). The insulating member 146 is a member having a U-shaped groove shape in which the antenna body 148 for generating inductively coupled plasma is arranged, and is arranged to separate the vacuum and the atmosphere. Preferably, a glass layer 147 is provided on the surface (especially the surface on the atmosphere side) of the insulating member 146 to increase the airtightness (prevent leakage). The antenna body 148 for generating inductively coupled plasma is arranged on the atmosphere side by passing through the insulating member 146. In this way, by arranging the antenna body 148 for generating inductively coupled plasma on the atmosphere side, the accuracy of its installation position can be improved, and the uniformity of the plasma density near the target 132 can be improved. In addition, the holding mechanism of the antenna body 148 for generating inductively coupled plasma can also be freely designed.

[0077] In addition, as Figure 5As shown, the antenna 126 for generating inductively coupled plasma can be composed of a plurality of antenna bodies 148 for generating inductively coupled plasma. That is, the antenna body 148 for generating inductively coupled plasma can be composed of a plurality of antenna bodies 148 for generating inductively coupled plasma and is arranged on the atmospheric side of the insulating member 146. In the metal tube 150 that constitutes the antenna body 148 for generating inductively coupled plasma, due to the skin effect, as the frequency increases, the AC resistance increases. For example, in the case where high-frequency power of 13.56 MHz is applied to the antenna body 148 for generating inductively coupled plasma, even if the wall thickness of the metal tube 150 is 5 mm, the current only flows in the region at a depth of about 17.7 μm from the surface of the metal tube 150. To prevent power loss caused by the skin effect, as Figure 5 shown, the antenna 126 for generating inductively coupled plasma can be configured in parallel with a plurality of antenna bodies 148 for generating inductively coupled plasma.

[0078] As Figure 3 shown, the gas introduction tube 138 is provided in the inner region of the plasma diffusion prevention plate 140 and is adjacent to the first antenna 126a. The gas introduction tube 138 is provided to introduce the sputtering gas into the film forming chamber 108. The gas introduction tube 138 is arranged along the longitudinal direction of the sputtering target 124, similar to the antenna 126 for generating inductively coupled plasma. The gas introduction tube 138 can have a structure in which a shower nozzle is provided on the metal tube, but is preferably formed of an insulating porous body, such as a tube of a ceramic porous body. By using a porous body in the gas introduction tube 138, the sputtering gas can be uniformly introduced along the longitudinal direction of the sputtering target 124.

[0079] The plasma diffusion prevention plate 140 is arranged to surround the region where the sputtering target 124 is arranged. The plasma diffusion prevention plate 140 is a box-shaped member and is arranged inside the film forming chamber 108 to form a space surrounded by the first chamber wall 109a and the plasma diffusion prevention plate 140. The plasma diffusion prevention plate 140 has a first surface 142 that is substantially parallel to the surface of the first chamber wall 109a and a second surface 143 that faces the first chamber wall 109a from the first surface 142. In addition, in the region surrounded by the plasma diffusion prevention plate 140, a deposition prevention plate 141 is provided so as to cover the surface of the first chamber wall 109a. On the first surface 142 of the plasma diffusion prevention plate 140, a first opening 144 is provided. The first opening 144 is provided at a position overlapping the target 132.

[0080] Figure 6The structural schematic diagram when observing the plasma diffusion prevention plate 140 from the front is shown. The sputtering target 124 is disposed in the region surrounded by the plasma diffusion prevention plate 140. When observing the sputtering target 124 from the front, the target material 132 is exposed from the first opening 144 of the plasma diffusion prevention plate 140.

[0081] The antennas 126 (the first antenna 126a and the second antenna 126b) for generating inductively coupled plasma are arranged at positions covered by the plasma diffusion prevention plate 140. The first antenna body 148a has a structure in which the first metal tube 150a and the second metal tube 150b are connected by the first capacitor 152a, and the second antenna body 148b has a structure in which the third metal tube 150c and the fourth metal tube 150d are connected by the second capacitor 152b.

[0082] On the plasma diffusion prevention plate 140, slit-shaped second openings 154 are provided from the second surface 143 to the first surface 142. The second openings 154 extend elongately in a direction crossing the length direction of the antennas 126 for generating inductively coupled plasma, and a plurality of them are provided. The second openings 154 are sputtering gas ejection holes and have a function of controlling the flow of the sputtering gas supplied to the space surrounded by the plasma diffusion prevention plate 140. That is, the second openings 154 have a function of controlling the conductance of the air flow so that the sputtering gas stays in the space surrounded by the plasma diffusion prevention plate 140 for a specified time to form a uniform gas pressure in the film formation region. In addition, the slit-shaped second openings 154 have a function of preventing the induced current generated in the plasma diffusion prevention plate 140 by the antennas 126 for generating inductively coupled plasma, and can improve the energy transfer efficiency from the antennas 126 for generating inductively coupled plasma to the inductively coupled plasma.

[0083] The plasma diffusion prevention plate 140 is preferably formed of a material having a secondary electron emission rate greater than 1. For example, the plasma diffusion prevention plate 140 is preferably formed of a magnesium alloy, a barium alloy, or a calcium alloy mainly composed of aluminum. In addition, preferably, in the plasma diffusion prevention plate 140 formed of these metal materials, the inner surface facing the sputtering target 124 is anodized. By forming an anodic oxidation film of a magnesium alloy, a barium alloy, or a calcium alloy on the inner surface of the plasma diffusion prevention plate 140, the secondary electron emission ratio can be greater than 1. Therefore, the surface of the anodic oxidation film has positive electrical resistivity and can prevent argon ions (positive ions) from incident and colliding with the plasma diffusion prevention plate 140. That is, it is possible to prevent argon ions (positive ions) from sputtering the plasma diffusion prevention plate 140 and reduce the impurities entering the thin film formed in the film formation chamber 108.

[0084] When precisely controlling the carrier concentration of an n-type oxide semiconductor film by sputtering, it is necessary to prevent the incorporation of impurities that cause an electron-killing effect. As a countermeasure, preferably, the inner surface of the plasma diffusion prevention plate 140 exposed to inductively coupled plasma is covered with an insulating film that does not cause an electron-killing effect. As an insulating film that does not cause an electron-killing effect, for example, silicon oxide (SiO2), magnesium oxide (MgO), and aluminum oxide (Al2O3) are exemplified. In particular, magnesium oxide (MgO) having a high secondary electron emission rate is preferably used as the insulating film, and silicon oxide, aluminum oxide, etc. containing magnesium oxide (MgO) are preferably used to cover the surface of the plasma diffusion prevention plate 140.

[0085] A plasma diffusion prevention plate 140 is provided to prevent the inductively coupled plasma formed by the antenna 126 for generating inductively coupled plasma from diffusing throughout the film deposition chamber 108. By forming a physical wall called the plasma diffusion prevention plate 140, the unnecessary diffusion of inductively coupled plasma in the film deposition chamber 108 can be prevented. That is, the film deposition chamber 108 has a structure in which inductively coupled plasma is generated in the region surrounded by the plasma diffusion prevention plate 140 and the deposition plate 141, and the inductively coupled plasma does not diffuse to other regions. An anodic oxidation film is formed on the surfaces of the plasma diffusion prevention plate 140 and the deposition plate 141, which may enhance the plasma confinement effect and increase the plasma density.

[0086] In a conventional magnetron sputtering device, in order to increase the film density of the oxide semiconductor film formation, the gas pressure during film formation is required to be maintained below 0.5 Pa. In addition, attention should be paid not only to the impurity gas detached from the inner wall of the film deposition chamber, but also to the components inside the film deposition chamber being sputtered and entering the film as impurities.

[0087] Since the conductivity of oxide semiconductors represented by InGaSnO x is n-type, when the film deposition chamber is made of stainless steel materials such as iron (Fe), chromium (Cr), and manganese (Mn) that have a large electron-killing effect, it is necessary to completely prevent the chamber wall from contacting the plasma. When forming an oxide semiconductor film, if the treatment for removing water (H2O), hydrocarbons, etc. adsorbed on the substrate surface is not performed, the film density will not increase, and a reliable thin film transistor cannot be manufactured.

[0088] Even before degassing the substrate surface and transporting it to the film-forming chamber, if the substrate temperature is not maintained above 150 °C, moisture (H2O) in the vacuum chamber will be adsorbed again, making it impossible to improve reproducibility. In addition, to increase the film density of the oxide semiconductor film that is still being formed, the substrate temperature needs to be raised above 200 °C to increase the crystallization rate. By adding a small amount of hydrogen gas (H2) to the sputtering gas (Ar + O2), contamination by impurity gases detached from the inner wall of the film-forming chamber can be reduced, and post-film heat treatment can be omitted. Since the heat treatment temperature after the completion of the device can be reduced to around 200 °C for thin-film transistors, the manufacturing cost is also greatly reduced.

[0089] Thus, since the film-forming chamber 108 has a structure that closes the inductively coupled plasma by the plasma diffusion prevention plate 140 and the anti-deposition plate 141, it is possible to prevent impurities (moisture (H2O), hydrogen (H2), hydrocarbons, etc.) adsorbed on the chamber wall 109 (the first chamber wall 109a, the second chamber wall 109b, etc.) from being absorbed by the film deposited on the substrate. Even if the film-forming chamber 108 is made of stainless steel (SUS304), contamination problems caused by iron (Fe), chromium (Cr), etc. can be prevented.

[0090] In addition, as Figure 7 shown, a grid 170 can also be provided at the first opening 144. By providing the grid 170, the closing effect on the inductively coupled plasma can be improved. The grid 170 is preferably formed of a metal material without an electron-killing effect. For example, the grid 170 is preferably formed of a metal material selected from titanium (Ti), tungsten (W), nickel (Ni), and tantalum (Ta). Therefore, plasma diffusion into the film-forming chamber 108 can be reliably prevented, and when depositing an oxide semiconductor film, it is possible to prevent electron-killing impurities from entering the film. By providing the grid 170, negative oxygen ions are likely to vertically incident on the substrate 200, and crystallization of the deposited oxide semiconductor film can be promoted.

[0091] The opening ratio of the grid 170 is preferably 70% or more. As Figure 7 shown, the wires (or grid patterns) forming the grid 170 are arranged to be inclined and cross within a range of 30 degrees to 60 degrees with respect to the moving direction (horizontal direction) of the substrate, so that the pattern of the grid 170 can be prevented from being transferred to the deposited film.

[0092] In addition, the plasma diffusion prevention plate 140 is preferably provided in a manner interposed between the antennas 126 (the first antenna 126a, the second antenna 126b) for generating inductively coupled plasma and the substrate 200. If there is no plasma diffusion prevention plate 140, then as Figure 8AAs shown, there is a problem that the film quality of the thin film deposited on the substrate 200 is affected by the antenna 126 (the first antenna 126a and the second antenna 126b) for generating an inductively coupled plasma. That is, since the surface 202 of the substrate 200 close to the antenna 126 (the first antenna 126a and the second antenna 126b) for generating an inductively coupled plasma is affected by the self-bias of the antenna 126 (the first antenna 126a and the second antenna 126b) for generating an inductively coupled plasma, the film quality of the deposited thin film is very different. In contrast, as Figure 8B shown, when a plasma diffusion prevention plate 140 is provided between the antenna 126 (the first antenna 126a and the second antenna 126b) for generating an inductively coupled plasma and the substrate 200, since the influence of the self-bias is shielded, the film quality of the thin film deposited on the substrate 200 can be kept constant. In addition, the antenna 126 for generating an inductively coupled plasma is a connection region (a region where two conductors are capacitively coupled, and the detailed content will be described later). By having the plasma diffusion prevention plate 140, the problem of plasma non-uniformity can be solved.

[0093] In addition, when the plasma diffusion prevention plate 140 is not provided, even in the mobile film formation method in which the substrate 200 moves in one direction in front of the first opening 144, as Figure 9 shown, there is also a problem that the film quality in the region overlapping with the capacitor 152 (the first capacitor 152a and the second capacitor 152b) connected to the metal tubes 150 (the first metal tube 150a and the second metal tube 150b, the third metal tube 150c and the fourth metal tube 150d) constituting the antenna main body 148 for generating an inductively coupled plasma is different.

[0094] That is, when the plasma diffusion prevention plate 140 is not provided, the plasma densities of the portions of the first capacitor 152a and the second capacitor 152b respectively provided on the first antenna 126a and the second antenna 126b are different, which affects the film quality of the thin film deposited on the antenna connection region 204 overlapping with this portion. Therefore, a uniform thin film cannot be formed on the entire surface of the substrate 200. On the contrary, when the plasma diffusion prevention plate 140 is provided, there is no region corresponding to the antenna connection region 204, and the influence of plasma non-uniformity is eliminated. Therefore, a uniform film can be formed on the entire surface of the substrate 200.

[0095] The film forming apparatus 100 is a mobile deposition method. As Figure 3 shown, the substrate 200 is mounted on the transfer tray 160 and transferred in front of the sputtering target 124. The substrate 200 is transferred at a position close to the plasma diffusion prevention plate 140. As Figure 3As shown, it is assumed that the distance from the surface of the target 132 to the surface of the substrate 200 is D1, and the interval between the surface of the substrate 200 and the surface of the plasma diffusion prevention plate 140 is D3. At this time, the plasma diffusion prevention plate 140 and the transfer tray 160 are arranged such that the interval D3 is 1 / 5 or less of the distance D1. For example, if the distance D1 is 55 mm, the interval D3 has a length of 5 mm.

[0096] In this way, by transferring the substrate 200 to a position close to the plasma diffusion prevention plate 140, the conductance when the sputtering gas supplied to the region surrounded by the plasma diffusion prevention plate 140 flows out into the film formation chamber 108 through the first opening 144 can be reduced. In addition, this structure has the effect of preventing impurities (such as moisture (H2O), hydrogen (H2), hydrocarbons, etc.) adsorbed on the chamber wall 109 from diffusing into the film formation region, and can exhibit the effect of improving the physical property reproducibility of the film to be formed.

[0097] Figure 10A and Figure 10B An example of a sputtering target 124 applicable to the moving deposition method is shown. Figure 10A A structure in which two target materials 132 (a first target material 132a and a second target material 132b) are fixed to the back plate 130 with a bonding material 131 is shown. Indium or an indium alloy is used as the bonding material 131.

[0098] The first target material 132a and the second target material 132b are composed of a combination of materials with different compositions or materials. For example, in the case where the target material is an oxide semiconductor, as the first target material 132a, a ternary oxide semiconductor target material containing indium (In), gallium (Ga), and tin (Sn) is used, and as the second target material 132b, an oxide semiconductor target material with a higher gallium (Ga) concentration than the first target material 132a is used. In this way, by arranging the two target materials in the transfer direction of the substrate, two layers with different compositions can be continuously deposited.

[0099] The first target material 132a and the second target material 132b are arranged on the back plate 130 at a prescribed interval to prevent breakage due to thermal expansion. The interval G1 is about 0.5 mm. In this case, the ends of the first target material 130a and the second target material 131b in the cross section are formed in a conical shape so that the support plate 132 or the bonding material 132 is not exposed in the interval part. Specifically, as Figure 10AAs shown, the first target 132a is formed with a conical surface in which the end portion on the upper surface side protrudes relative to the bottom surface in contact with the bonding material 131, and the second target 132b is formed with a conical surface in which the bottom surface protrudes relative to the upper surface side. By arranging the first target 132a and the second target 132b so that these two conical surfaces engage with each other, when observing the sputtering target 124 from a top view perspective, the backplate 130 and the bonding material 131 can be prevented from being exposed. That is, even when two types of targets are arranged on one backplate 130, sputtering of the backplate 130 and the bonding material 131 in the boundary region can be prevented, thereby preventing impurities from entering the deposited film.

[0100] In the film formation chamber 108, the substrate 200 is transported in a certain direction in front of the sputtering target 124 at a certain speed. Therefore, by reducing the width of the second target 132b relative to the first target 132a, the film thickness of the deposited thin film can be made different. For example, by reducing the width of the second target 132b relative to the width of the first target 132a, the film thickness of the thin film deposited by the first target 132a can be made thicker, and the film thickness of the thin film deposited by the second target 132b can be made thinner.

[0101] Figure 10B An example in which three targets 132 (the first target 132a, the third target 132c, and the second target 132b) are arranged is shown. In this case, Figure 10A the same as the example shown, the side end portions adjacent to each target are formed into a conical shape. Specifically, the third target 132c sandwiched between the first target 132a and the second target 132b has a trapezoidal cross-sectional shape. By arranging the first target 132a and the second target 132b with opposite conical surfaces on both sides of the third target 132c having such a cross-sectional shape, the sputtering target 124 has a structure in which the backplate 130 and the bonding material 131 are not exposed in a top view perspective.

[0102] Figure 11Details of the antenna 126 (first antenna 126a, second antenna 126b) for generating an inductively coupled plasma are shown. The first antenna 126a includes a first insulator 146a and a first antenna body 148a, and the second antenna 126b includes a second insulator 146b and a second antenna body 148b. The first antenna body 148a is a rod-shaped antenna in which a first metal tube 150a and a second metal tube 150b are connected by a first capacitor 152a formed on an antenna connection region 204, and the second antenna body 148b is a rod-shaped antenna in which a third metal tube 150c and a fourth metal tube 150d are connected by a second capacitor 152b formed on the antenna connection region 204. The first antenna body 148a and the second antenna body 148b have such a structure as to be able to reduce the impedance. Therefore, even when the antenna body 148 for generating an inductively coupled plasma is extended, an increase in impedance can be prevented, and a large potential difference can be prevented from being generated at both ends of the antenna body 148 for generating an inductively coupled plasma. As a result, it is also possible to cope with an increase in the size of the sputtering target 124.

[0103] Figure 12 A cross-sectional structure of the antenna connection region 204 of the antenna body 148 for generating an inductively coupled plasma is shown. The antenna connection region 204 has a structure in which a first metal tube 150a and a second metal tube 150b (or a third metal tube 150c and a fourth metal tube 150d) are embedded in a hollow tube 172 formed of an insulating material. An O-ring 153 is provided at a portion where the hollow tube 172 is fitted with the first metal tube 150a and the second metal tube 150b to maintain airtightness, and has a structure that does not leak even when cooling water flows. The O-ring 153 preferably has heat resistance, for example, a fluororubber-based one is used.

[0104] A conductive layer 174 serving as an electrode of the capacitor 152 is formed on the inner surface of the hollow tube 172. In the conductive layer 174, in order to achieve low resistance, a first conductive layer 174a is formed by copper plating, and in order to prevent corrosion of the copper plating film, a second conductive layer 174b is formed by nickel plating (Ni) or tin plating (Sn). In addition, as described above, a conductive layer 151 is also formed on the inner surfaces of the first metal tube 150a and the second metal tube 150b.

[0105] The conductive layer 174 forms a capacitor 152 by being disposed opposite to the first metal tube 150a and the second metal tube 150b through a hollow tube 172 formed of an insulating material. That is, the first metal tube 150a and the second metal tube 150b are capacitively coupled by being inserted into the hollow tube 172 having the conductive layer 174 formed on its inner surface, forming an antenna body 148 for generating inductively coupled plasma. Thus, by disposing the hollow tube 172 formed of an insulating material at the inner peripheral portion of the first metal tube 150a and the second metal tube 150b, unevenness of the antenna body 148 for generating inductively coupled plasma can be reduced, and homogenization of the inductively coupled plasma can be achieved.

[0106] In addition, since the antenna body 148 for generating inductively coupled plasma is provided on the atmosphere side, a variable capacitor 176 can be provided in parallel in the capacitor 152. Therefore, the impedance of the antenna body 148 for generating inductively coupled plasma can be adjusted precisely or over a wide range. Therefore, the antenna 126 for generating inductively coupled plasma can be easily matched with the high-frequency power supply 120.

[0107] Furthermore, in the antenna body 148 for generating inductively coupled plasma, since the capacitor 152 is provided in the flow path of the cooling water (the capacitor 152 is in contact with the cooling water), heat generation of the capacitor 152 can be effectively suppressed. With this configuration, failures and damages caused by heat generation of the capacitor 152 can be prevented, and the high-frequency power applied to the antenna 126 for generating inductively coupled plasma can be increased to a large power.

[0108] In addition, as Figure 11 shown, when applying high-frequency power of 13.56 MHz to the antenna 126 for generating inductively coupled plasma, if the length of the antenna body 148 for generating inductively coupled plasma exceeds 3 m, the problem of standing waves cannot be ignored. However, by dividing the antenna body 148 for generating inductively coupled plasma into two or more pieces, as shown in FIGS. 16 and 17, and connecting them in series through the variable capacitor 176 for resonance, the standing wave problem can be solved.

[0109] The antenna body 148 for generating an inductively coupled plasma is connected to a high-frequency power supply 120 with an oscillation frequency of 13.56 MHz or 27 MHz. Specifically, the first antenna body 148a is connected to the first high-frequency power supply 120a, and the second antenna body 148b is connected to the second high-frequency power supply 120b. The phases of the high-frequency power output by the first high-frequency power supply 120a and the second high-frequency power supply 120b may be the same, but it is more preferably staggered by half a wavelength (180 degrees). Thus, the plasma density on the surface of the target 132 can be increased. In addition, the first antenna body 148a is also connected to the first variable capacitor 158a, and the second antenna body 148b is connected to the second variable capacitor 158b. The variable capacitor 158 (the first variable capacitor 158a and the second variable capacitor 158b) is provided to adjust the impedance of the antenna body 148 (the first antenna body 148a and the second antenna body 148b) for generating an inductively coupled plasma, so as to easily achieve impedance matching with the high-frequency power supply 120 (the first high-frequency power supply 120a, the second high-frequency power supply 120b).

[0110] The antenna body 148 (the first antenna body 148a, the second antenna body 148b) for generating an inductively coupled plasma is also connected to an AC power supply 122 with a frequency of 10 kHz to 1000 kHz. A coil 156 for blocking high frequencies is inserted between the antenna body 148 (the first antenna body 148a, the second antenna body 148b) for generating an inductively coupled plasma and the AC power supply 122. In addition to the high-frequency power, by applying an AC voltage to the antenna body 148 (the first antenna body 148a, the second antenna body 148b) for generating an inductively coupled plasma, the plasma density on the surface of the target 132 can be increased.

[0111] Furthermore, by superimposing the AC voltage on the high-frequency power, the deposits (products sputtered from the target 132) attached to the insulating member 146 can be removed by the sputtering phenomenon. Thus, the change in discharge characteristics over time can be suppressed. In particular, in the case of forming a transparent conductive film with a low resistance value, Figure 11 the circuit structure of the antenna 126 for generating an inductively coupled plasma shown is advantageous in obtaining stable discharge. Note that in the case of forming an oxide semiconductor film with a high resistance value, even if deposits adhere to the insulating member 146, it is not significantly affected, so the AC power supply 122 is not necessary. On the other hand, when the interval between the first antenna 126a and the second antenna 126b is increased to more than 300 mm, the plasma density in the central region of the sputtering target 124 decreases. Therefore, by applying an AC voltage between the first antenna body 148a and the second antenna body 148b using the AC power supply 122, the plasma density can be made uniform.

[0112] The pulse power supply 123 is connected to the sputtering target 124. The pulse power supply 123 applies a negative pulse voltage of approximately -100V to -600V to the sputtering target 124. As Figure 13 shown, by applying the negative pulse voltage at the timing when the AC voltage applied to the antenna body 148 for generating the inductively coupled plasma becomes 0V, sputtering particles can be emitted in the direction perpendicular to the substrate. Therefore, a dense film can be deposited.

[0113] Figure 14 Schematically shows the relationship between the target voltage and the film density when an InGaZnO film, which is an oxide semiconductor film, is sputter-deposited. The advantage of the sputtering method using inductively coupled plasma is that the two power supplies, namely the power supply for generating and maintaining the plasma and the power supply for controlling the sputter film formation, can be separated and independently controlled. In the conventional DC magnetron method, if the voltage applied to the sputtering target is below -300V, the generation of the plasma becomes uneven and stable discharge cannot be maintained.

[0114] In contrast, in the case of using inductively coupled plasma, if the high-frequency power applied to the antenna for generating the inductively coupled plasma is increased to increase the plasma density, a large amount of negative oxygen ions and oxygen radicals can be generated. In the method using inductively coupled plasma, since there is no effect of confining the plasma near the sputtering target by the magnetic field of the magnet, the plasma can uniformly contact the substrate surface. Therefore, the oxidation reaction between the metal and oxygen atoms can be promoted.

[0115] In the sputtering method using inductively coupled plasma, when forming the InGaZnO film, by setting the voltage applied to the sputtering target to about -200V, the damage to the film deposited on the substrate surface can be controlled to a minimum, and at the same time, the crystallization rate can be increased. At this time, the film density of the InGaZnO film can reach 6.30 g / cm 3 ³. This film density is close to the theoretical value of 6.378 g / cm 3 ³.

[0116] In the conventional magnetron method, if the target voltage is not increased to above -300V, stable discharge cannot be maintained, so the damage to the film will increase and it is difficult to make the film density reach 6.25 g / cm 3 ³ or more. In contrast, the film-forming apparatus 100 using inductively coupled plasma according to the present embodiment can increase the film density of oxide semiconductor films including various compositions represented by the InGaZnO film, and can reduce the offset amount of the threshold voltage Vth of the thin film transistor. In other words, the film-forming apparatus 100 using inductively coupled plasma according to the present embodiment can improve the long-term reliability of the thin film transistor.

[0117] Figure 15The structure of the pretreatment chamber 104 is shown. The pretreatment chamber 104 is provided with a substrate stage 114 and a high-frequency discharge electrode 115. The substrate stage 114 is attached with a lifting mechanism 164 that floats the placed substrate 200 upward. The substrate stage 114 has the function of providing pins 162 that contact the substrate 200 at multiple positions, and the pins 162 project upward through the lifting mechanism 164 to lift the substrate 200 to a floating state.

[0118] The substrate stage 114 is formed of a conductor to be used as a ground electrode, and has the same potential as the chamber wall of the pretreatment chamber 104. In the substrate stage 114, a heater for heating a substrate (not shown) may also be incorporated. The high-frequency discharge electrode 115 is arranged to face the substrate stage 114. The high-frequency discharge electrode 115 and the substrate stage 114 are connected to a high-frequency power supply 120 with an oscillation frequency of 13.56 MHz or 27 MHz. The pretreatment chamber 104 is also provided with a gas introduction tube 166. As a pretreatment gas, for example, nitrogen (N2) gas, oxygen (O2) gas, or nitrous oxide (N2O) gas is introduced from the gas introduction tube 166. Additionally, instead of the gas introduction tube 166, a high-frequency discharge electrode 115 formed of a shower plate can be used, and gas can be introduced from there. The pressure during plasma generation in the pretreatment is preferably in the range of 10 Pa to 10 3 Pa.

[0119] In the pretreatment chamber 104, when the pretreatment gas is introduced and high-frequency power is applied to the high-frequency discharge electrode 115, a high-frequency discharge plasma 168 is generated. After the high-frequency discharge plasma 168 reaches a stable state, the substrate 200 is lifted by the pins 162 and set in a state of floating on the substrate stage 114. In this state, the high-frequency discharge plasma 168 is generated in such a way that it wraps around not only the surface of the substrate 200 but also the back side. Therefore, not only can molecules of impurities or contaminants such as moisture adsorbed on the surface (the surface of the deposited film) of the substrate 200 be removed, but also those adsorbed on the back and side surfaces can be removed. Since the pins 162 are exposed to the plasma, they are preferably formed of insulating ceramic to prevent the release of impurities.

[0120] So far, as a pretreatment of the substrate 200, plasma treatment has been performed in a vacuum. However, generally, only the surface side of the substrate 200 is subjected to plasma treatment, and the back side is not exposed to plasma. In this state, even if the surface of the substrate 200 is cleaned, due to the remaining moisture adsorbed on the back side, outgassing continues even after the substrate 200 is transferred to the film-forming chamber. In particular, like when forming an oxide semiconductor film, when the gas pressure during sputtering film formation is low, degassing treatment only on one surface side of the substrate 200 is not sufficient. As a result, no matter how high the vacuum of the film-forming chamber is evacuated, since adsorbed molecules (moisture (H2O), hydrogen (H2), hydrocarbons, etc.) continue to be released from the back side of the substrate 200, there is a large difference in film quality between the vicinity of the center and the vicinity of the periphery of the substrate 200. For example, when forming an oxide semiconductor film by sputtering method, since the degassing components released from the back side of the substrate 200 cannot be controlled, the carrier concentrations in the vicinity of the center and the vicinity of the periphery of the substrate 200 are very different. The larger the size of the substrate 200, the greater this problem becomes.

[0121] As a degassing treatment of the substrate 200, heating at a temperature of 200 °C or higher in a vacuum can be considered, but it takes several hours to completely remove the adsorbed moisture, which is not suitable for mass production. When forming an oxide semiconductor film using a single wafer, it is not practical to perform heat treatment on each substrate 200 for several hours.

[0122] However, as shown in this embodiment, in the pretreatment chamber 104, by floating the substrate 200 to perform plasma treatment, not only the surface but also the back side is exposed to plasma, so that degassing of the entire area can be performed, thereby enabling the entire substrate to be cleaned in a short time and enabling precise control of the carrier concentration.

[0123] Again, in the film-forming apparatus 100 for forming an oxide semiconductor film, it is important to forcibly degas the adsorbed components (moisture (H2O), hydrogen (H2), hydrocarbons) adsorbed on the entire surface of the substrate 200 with nitrogen plasma and oxygen plasma before sputtering film formation. Therefore, a homogeneous oxide semiconductor film having a constant carrier concentration on the entire surface of the substrate 200 can be manufactured.

[0124] The film formation chamber 108 of the above-described film forming apparatus 100 is preferably formed of a metal material with little outgassing. For example, when forming an oxide semiconductor film for a thin film transistor, it is necessary to increase the film density to improve reliability. To increase the film density, the sputtering pressure during sputter film formation needs to be around 0.1 Pa to 1.5 Pa. In this pressure range, since inductively coupled plasma diffuses throughout the film formation chamber 108, the inner wall is exposed to the plasma. When positive ions in the plasma collide with the inner wall of the film formation chamber, a large amount of adsorbed molecules such as moisture (H2O), hydrogen (H2), hydrocarbons, etc. are desorbed. These impurities cause problems in the transistor characteristics formed using the oxide semiconductor film.

[0125] In consideration of strength, the film formation chamber 108 of the film forming apparatus 100 shown in this embodiment uses stainless steel. However, elements such as iron (Fe), molybdenum (Mo), manganese (Mn), etc. as components of stainless steel are electron-killing impurities for n-type oxide semiconductors, and thus are not preferred. That is, when stainless steel is exposed in the film formation chamber 108, the characteristics of the transistor using the oxide semiconductor film are adversely affected. In a conventional sputtering apparatus, since stainless steel has always been exposed in the film formation chamber, the manufacturing yield of the transistor using the oxide semiconductor film is reduced, which is the main cause of reducing process reproducibility.

[0126] To solve such problems, the film forming apparatus 100 according to this embodiment employs a structure in which a plasma diffusion prevention plate 140 formed of metals such as magnesium (Mg), aluminum (Al), titanium (Ti), tungsten (W), nickel (Ni), etc. is provided in the film formation chamber 108 to enclose the plasma. In addition, in order to increase the electron density and discharge stability in the plasma, a film of oxides of alkaline earth metals such as magnesium oxide (MgO), barium oxide (BaO), strontium oxide (SrO), calcium oxide (CaO), etc. having a high secondary electron emission rate, or an insulating film containing silicon oxide, aluminum oxide, yttrium oxide, etc. containing them is provided on the surface of the plasma diffusion prevention plate 140.

[0127] As Figure 1 and Figure 2 shown, the film forming apparatus 100 is provided with a first film formation chamber 108a and a second film formation chamber 108b. With this structure of the first film formation chamber 108a and the second film formation chamber 108b, two oxide semiconductor films having different film qualities can be laminated. For example, a first oxide semiconductor film can be deposited in the first film formation chamber 108a, and a second oxide semiconductor film can be deposited in the second film formation chamber 108b.

[0128] For example, a target material of an oxide semiconductor can be used in the first film formation chamber 108a, and film formation can be performed using only argon (Ar) or using argon (Ar) and oxygen (O2) as sputtering gases. In the second film formation chamber 108b, film formation is performed using argon (Ar) and oxygen (O2) (at this time, the oxygen partial pressure is higher than the condition in the first film formation chamber 108a). In the sputtering film formation of the oxide semiconductor film, increasing the oxygen partial pressure can increase the density of oxygen negative ions and can increase the irradiation density of oxygen negative ions on the film deposition surface. Thus, compared with the oxide semiconductor film deposited in the first film formation chamber 108a, the oxide semiconductor film deposited in the second film formation chamber 108b can reduce the carrier density and can also improve the crystallinity.

[0129] In addition, by applying a negative pulse voltage to the sputtering target 124, oxygen negative ions generated during the discharge process reach the deposition surface of the oxide semiconductor film during the application of the pulse voltage, thereby promoting the densification of the film and making it easier to crystallize. In the present embodiment, the antenna 126 for generating inductively coupled plasma can generate a large amount of oxygen radicals, and since the inductively coupled plasma contacts or approaches the surface of the substrate 200, metal elements are more likely to react with oxygen, so the probability of unreacted oxygen (O2) molecules entering the film can be reduced.

[0130] In this way, the film formation apparatus 100 according to the present embodiment employs a moving film formation method and has a structure in which a plurality of first film formation chambers 108a and second film formation chambers 108b are connected in series, so that when depositing an oxide semiconductor film, the carrier concentration can be precisely controlled. Note that although the present embodiment mainly describes an example of manufacturing an oxide semiconductor film by the film formation apparatus 100, it is not limited thereto, and the film formation apparatus 100 can also be applied to manufacturing a transparent conductive film, other semiconductor films, and metal films.

[0131] In the present embodiment, as shown in Figure 16A the front view and Figure 16B the cross-sectional view (corresponding to the cross-sectional structure between A1 - A2 shown in Figure 16A ), the first antenna 126a and the second antenna 126b are rod-shaped antennas extending in the same direction as the length direction of the sputtering target 124 with substantially the same length. In this example, the first insulating member 146a and the second insulating member 146b having a U-shaped groove shape are provided to protrude inwardly into the region surrounded by the first chamber wall 109a and the plasma diffusion prevention plate 140, and the first antenna main body 148a and the second antenna main body 148b are provided to be surrounded by the first insulating member 146a and the second insulating member 146b having a U-shaped groove shape.

[0132] However, the first antenna 126a and the second antenna 126b are not limited to Figure 16A and Figure 16BIn the manner shown, the U-shaped first antenna 126a and the second antenna 126b can also be divided into a plurality of parts and arranged. For example, as Figure 17A the front view of Figure 17B and the cross-sectional view of Figure 17A (corresponding to the cross-sectional structure between B1 - B2 shown in Figure 17A and Figure 17B show), a plurality of first antenna bodies 148a_1 to 148a_3 and a plurality of second antenna bodies 148b_1 to 148b_3 can be divided along the length direction of the sputtering target 124. With such an arrangement of the first antenna 126a and the second antenna 126b, the plasma density can also be increased, and a dense film can be deposited. In addition,

[0133] The present invention is not limited to the above-described embodiments and can be appropriately modified without departing from the gist. In addition, the respective embodiments can be appropriately combined.

[0134] Figure 18A An example of an element manufactured using the film-forming apparatus 100 is shown. An example of the element is a transistor, Figure 18A and the cross-sectional structure of the transistor 230 is shown. The transistor 230 includes an oxide semiconductor layer 216 formed on the substrate 200 by the film-forming device 100.

[0135] More specifically, the transistor 230 is formed on the first insulating layer 210 formed on the surface of the substrate 200. On the first insulating layer 210, a pair of first conductive layers 212a for forming a source electrode and first conductive layers 212b for forming a drain electrode are provided. The first conductive layers 212a, 212b are formed of a transparent conductive film such as indium tin oxide (ITO), indium zinc oxide (IZO), etc. In order to reduce the resistance, second conductive layers 214a, 214b formed of a metal material such as aluminum (Al) can be provided on the first conductive layers 212a, 212b.

[0136] The oxide semiconductor layer 216 is formed to cover the first conductive layers 212a, 212b (and the second conductive layers 214a, 214b). A second insulating layer 218 serving as a gate insulating layer is provided on the oxide semiconductor layer 216, and a gate electrode 220 is provided thereon so as to overlap with the oxide semiconductor layer 216.

[0137] The oxide semiconductor layer 216 may be formed of a plurality of layers having different compositions and crystallinities. For example, as Figure 18B shown, it may have a structure in which a first oxide semiconductor layer 216a and a second oxide semiconductor layer 216b are stacked. Preferably, the first oxide semiconductor layer 216a is a ternary oxide semiconductor containing indium (In), gallium (Ga), and tin (Sn), and the second oxide semiconductor layer 216b has a higher proportion of gallium (Ga) and higher crystallinity than the first oxide semiconductor layer 216a. The second oxide semiconductor layer 216b is formed thinner than the first oxide semiconductor layer 216a. Due to the high concentration of gallium (Ga), the second oxide semiconductor layer 216b has physical properties such as a wide bandgap and a low carrier concentration compared to the first oxide semiconductor layer 216a. For example, the first oxide semiconductor layer 216a is formed with a film thickness of 40 nm to 60 nm, while the second oxide semiconductor layer 216b is formed with a film thickness of about one-tenth, i.e., 4 nm to 6 nm.

[0138] In the transistor 230, by providing such a second oxide semiconductor layer 216b between the first oxide semiconductor layer 216a and the second insulating layer 218 (gate insulating layer), a channel region through which carriers flow is formed on the first oxide semiconductor layer 216a, that is, a so-called buried channel is formed. That is, the transistor 230 can allow carriers to flow through the channel region without being affected by defects formed at the interface between the second insulating layer 218 (gate insulating layer) and the oxide semiconductor layer 216. By having such a structure, the transistor 230 can achieve stabilization of characteristics and reduction of characteristic variations.

[0139] As Figure 18C shown, in the oxide semiconductor layer 216, a third oxide semiconductor layer 216c may be provided between the first oxide semiconductor layer 216a and the second oxide semiconductor layer 216b. Although the third oxide semiconductor layer 216c is the same ternary oxide semiconductor, the concentration of indium (In) is higher than that of the first oxide semiconductor layer 216a and the second oxide semiconductor layer 216b. By providing such a third oxide semiconductor layer 216c, the field-effect mobility of the transistor 230 can be improved.

[0140] According to the film-forming apparatus 100 according to the present embodiment, Figure 18B the structure of the oxide semiconductor layer 216 shown in Figure 10A can be manufactured by using the sputtering target 124 shown in Figure 18C and the structure of the oxide semiconductor layer 216 shown in Figure 10B can be manufactured by using the sputtering target 124 shown in

[0141] Figure 10A and Figure 10B For the composite split target shown, in a conventional magnetron sputtering apparatus, abnormal discharge easily occurs in the split portion and it cannot be used. On the other hand, in a method without using a magnet, since argon ions charged positively are incident almost uniformly on the entire surface of the sputtering target, abnormal discharge hardly occurs. In addition, since the entire surface of the sputtering target is sputtered uniformly, heat generation on the sputtering target surface also occurs uniformly. Therefore, cracks are not easily generated due to the thermal stress of the sputtering target.

[0142] InGaSnO target capable of preparing an oxide semiconductor film with high electron mobility x target, in a conventional magnetron sputtering apparatus, fine cracks called hairline cracks easily occur in the sputtering target, so it cannot be used in a mass production factory. On the contrary, the film forming apparatus 100 according to the present embodiment does not use a magnet, so plasma does not concentrate locally and local heating does not occur. Therefore, hairline cracks caused by thermal stress are also hardly generated.

[0143] As in the film forming apparatus 100 according to the present embodiment, by the plasma diffusion prevention plate 140, inductively coupled plasma (ICP) is prevented from diffusing to the entire internal region of the film forming chamber 108, and even in a moving film forming method of performing sputtering film formation while moving a substrate, film formation can be performed without reducing the deposition rate.

[0144] In addition, by applying a negative pulse voltage to the sputtering target 124, stable sputtering film formation can be performed even if the target material 132 is a high-resistance material. In addition, since negative oxygen ions can be made to vertically incident on the substrate 200, even when the film forming gas pressure is close to 1.5 Pa, a reduction in film density can be prevented. For example, an oxide semiconductor film having high mobility and high reliability can be deposited on an eleventh-generation glass substrate (3000 mm × 3320 mm) by increasing the film density.

[0145] It should be noted that Figure 18A the structure of the transistor 230 shown is an example, and the film forming device 100 according to the present embodiment can be used to manufacture oxide semiconductor transistors having various structures, whether top-gate type or bottom-gate type.

[0146] Second Embodiment

[0147] This embodiment shows an example of a film forming apparatus that can continuously perform sputtering and vacuum vapor deposition (and / or electron beam vapor deposition) using inductively coupled plasma. The film forming apparatus shown in this embodiment can be applied to the manufacture of an organic electroluminescent element (or an organic electroluminescent display device), for example. The following description will focus on the parts that are different from the film forming apparatus 100 shown in the first embodiment.

[0148] Figure 19 The overall structure of the film forming apparatus 101 according to the present embodiment is shown. The film forming apparatus 101 includes a loading / unloading chamber 102 for storing substrates before and after film formation, a pretreatment chamber 104 for performing pretreatment of substrates, a first transport chamber 106a provided with a transport robot 116, a second transport chamber 106b provided with a platen mechanism 118, a first film forming chamber 108a for performing sputtering film formation, a third transport chamber 106c provided with a platen mechanism 118, a fourth transport chamber 106d provided with a transport robot 116, a third film forming chamber 108c provided with an evaporation source 111, a fourth film forming chamber 108d, and a fifth film forming chamber 108e. These chambers are connected by gate valves and are provided with a vacuum exhaust device (not shown).

[0149] The structures of the pretreatment chamber 104, the first conveying chamber 106a, the second conveying chamber 106b, the third conveying chamber 106c and the fourth conveying chamber 106d are respectively the same as those of the first embodiment. The first film forming chamber 108a is a chamber for performing sputtering film formation by inductively coupled plasma, and performs film formation of the electron injection layer described later. The third film forming chamber 108c and the fourth film forming chamber 108d are provided with an evaporation source 111, and are chambers for performing vacuum vapor deposition, and are chambers for performing film formation of organic films such as the light-emitting layer and the hole transport layer described later. The fifth film forming chamber 106e is a chamber provided with an evaporation source 111, and performs film formation of the anode described later by vacuum vapor deposition (and / or electron beam vapor deposition).

[0150] exist Figure 19 In the film forming apparatus 101 shown, a chamber for sputtering film formation using inductively coupled plasma and a chamber for film formation using vacuum vapor deposition (and / or electron beam vapor deposition) are connected via a transfer chamber, so that inorganic films and organic films can be continuously deposited in a vacuum. In addition, a second transfer chamber 106b and a third transfer chamber 106c provided with a platen mechanism 118 are provided across a first film forming chamber 108a for sputtering film formation based on inductively coupled plasma, thereby sputtering film formation can be performed in a state where the substrate 200 is vertical or inclined by 20 degrees from the vertical, and in film formation based on vacuum vapor deposition (and / or electron beam vapor deposition), the substrate 200 can be maintained in a substantially horizontal state.

[0151] Note that the number of chambers for film formation by vacuum vapor deposition (and / or electron beam vapor deposition) is arbitrary and can be appropriately connected according to the number of layers of the vapor-deposited film and the film type.

[0152] Figure 20 A diagram showing the configuration of the film-forming apparatus 101 shows the main components provided or connected to the pretreatment chamber 104, the first transfer chamber 106a, the second transfer chamber 106b, the first film-forming chamber 108a, the third transfer chamber 106c, the fourth transfer chamber 106d, and the third film-forming chamber 108c, other than the load / unload chamber 102. The configurations of the other chambers are the same as those of the first embodiment, except for the third film-forming chamber 108c.

[0153] In the third film-forming chamber 108c where film formation is performed by vacuum vapor deposition (and / or electron beam vapor deposition), in addition to a turbo molecular pump and a dry pump, a cryopump is added as the vacuum exhaust system 110. High-vacuum exhaust is achieved by these vacuum exhaust systems 110, and moisture remaining in the chamber can be effectively removed. For film formation by vacuum vapor deposition, a moving deposition method in which the substrate moves in front of the linear evaporation source 111 or a scanning film-forming method in which the evaporation source 111 moves to scan the surface of the substrate can be employed.

[0154] Since the film-forming apparatus 101 employs a moving deposition method in film formation by sputtering and in film formation by vacuum vapor deposition (and / or electron beam vapor deposition), it can accommodate substrates of various sizes. For example, the film-forming apparatus 101 can be used for film formation on an 11th-generation glass substrate (3000 mm × 3320 mm).

[0155] Figure 21 An example of an element manufactured using the film-forming apparatus 101 is shown. Figure 21 The element shown shows a cross-sectional structure of an organic electroluminescent element 300. The organic electroluminescent element 300 has the following structure, in which a carrier injection amount control electrode 302, a first insulating layer 304, a first electrode (cathode) 306, an electron transport layer 308, a second insulating layer 310 having an opening 311, an electron injection layer 312, a light-emitting layer 314, a hole transport layer 316, a hole injection layer 318, and a second electrode (anode) 320 are stacked on a substrate 200. The organic electroluminescent element 300 has a region overlapping with the carrier injection amount control electrode 302, the first insulating layer 304, the electron transport layer 308, the electron injection layer 312, the light-emitting layer 314, the hole transport layer 316, the hole injection layer 318, and the second electrode (anode) 320 in the region where the opening 311 is provided.

[0156] The carrier injection amount control electrode 302 is insulated from the electron transport layer 308 and has a function of controlling the amount of carriers (electrons) injected from the electron transport layer 308 via the electron injection layer 312 into the light-emitting layer 314 and the light-emitting position in the light-emitting layer 314 by applying a positive bias voltage. Since the organic electroluminescent element 300 is a bottom emission type, the carrier injection amount control electrode 302 is formed of a transparent conductive film.

[0157] The electron transport layer 308 has a two-layer structure. The first electron transport layer 308a is provided on the first insulating layer 304 with an area larger than that of the carrier injection amount control electrode 302. The first electrode (cathode) 306 is provided outside the opening 311 (the region overlapping with the second insulating layer 310). The first electrode (cathode) 306 can be formed, for example, as a two-layer structure of a first conductive layer 306a and a second conductive layer 306b, and the end of the first conductive layer 306a overlaps with the carrier injection amount control electrode 302. The first conductive layer 306a is formed of a transparent conductive film such as ITO or IZO and has a function of forming an ohmic contact with the electron transport layer 308 and injecting electrons. The second conductive layer 306b is appropriately provided to reduce the resistance of the first electrode (cathode) 306.

[0158] The first electron transport layer 308a is formed of a metal oxide having semiconductor characteristics. As such a metal oxide, In2O3-Ga2O3-SnO2-ZnO-based oxide materials, In2O3-Ga2O3-SnO2-based oxide materials, In2O3-SnO2-ZnO-based oxide materials, In2O3-Al2O3-ZnO-based oxide materials, Ga2O3-SnO2-ZnO-based oxide materials, Ga2O3-Al2O3-ZnO-based oxide materials, SnO2-Al2O3-ZnO-based oxide materials, In2O3-ZnO-based oxide materials, SnO2-ZnO-based oxide materials, Al2O3-ZnO-based oxide materials, Ga2O3-SnO2-based oxide materials, Ga2O3-ZnO-based oxide materials, Ga2O3-MgO-based oxide materials, MgO-ZnO-based oxide materials, SnO2-MgO-based oxide materials, In2O3-MgO-based oxide materials, In2O3-based oxide materials, Ga2O3-based metal oxide materials, SnO2-based metal oxide materials, ZnO-based metal oxide materials, etc. can be used. Such a first electron transport layer 308a can be formed by a sputtering method using the film forming apparatus 100 shown in the first embodiment.

[0159] A second insulating layer 310 is provided on the first electron transport layer 308a. An opening 311 is provided on the second insulating layer 310 to expose the surface of the first electron transport layer 308a. The second electron transport layer 308b is formed of a metal oxide material having the same semiconductor characteristics as the first electron transport layer 308a. The second electron transport layer 308b can be formed by a sputtering method or can be formed in the area of the opening 311 by a coating method.

[0160] At this time, the second insulating layer 310 is preferably formed of an insulating film having polarity. Such a second insulating layer 310 can be formed using a linear fluorinated organic material. As the linear fluorinated organic material, for example, a fluoroalkylsilane (FAS)-based material is used. As the fluoroalkylsilane (FAS)-based material, for example, H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS), tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS), etc. can be used. The second insulating layer 310 is formed using a linear fluorinated organic material, thereby forming a hydrophobic surface. An opening 311 is formed on such a second insulating layer 310. The hydrophobicity of the second insulating layer 310 is stronger on the surface, and the side wall surface of the opening 311 becomes a hydrophilic state compared to the surface.

[0161] When manufacturing the second electron transport layer 308b by a coating method, a composition solution containing the above-mentioned quaternary oxide layer material, ternary oxide layer material, binary oxide layer material, monovalent oxide layer material, or their precursors is coated on the second insulating layer 310 having the opening 311, and then dried and sintered. As a specific example, aluminum (Al), indium (In), gallium (Ga), etc. are doped into zinc oxide (ZnO) as trivalent metal elements, and fired so that the resistivity is in the range of 102 Ω·cm to 105 Ω·cm. When the surface of the second insulating layer 310 has hydrophobicity, by appropriately adjusting the viscosity of the coated composition, the coating film is selectively formed on the opening 311. After firing, the second electron transport layer 308b has a hydrophilic side wall surface through the opening 311, the contact surface with the second insulating layer 310 bulges upward, and a cross-sectional shape with a gentle conical inclined surface is formed as it faces inward. The average film thickness of the second electron transport layer 308b may be 200 nm or more, preferably 400 nm or more. By making the second electron transport layer 308b have such a film thickness, the short-circuit defect of the organic electroluminescent element 300 can be sharply reduced, and the yield can be improved.

[0162] The organic electroluminescent device 300 can divide the light-emitting region by providing a second insulating layer 310 having an opening 311 formed therein to expose the upper surface of the first electron transport layer 308a before forming the light-emitting layer 314. In addition, since the end portion of the second electron transport layer 308b provided on the opening 311 has a tapered cross-sectional shape that gently slopes from the wall surface of the opening 311, the step coverage of the electron injection layer 312 and the light-emitting layer 314 formed in the next stage can be improved.

[0163] The electron injection layer 312 is formed of a material having a small work function in order to inject electrons into the light-emitting layer 314. For example, the electron injection layer 312 is formed of a material containing calcium (Ca) oxide and aluminum (Al) oxide. As an example, the electron injection layer 312 is formed of the electron compound C12A7 (12Ca·7Al2O3). The electron compound C12A7 has semiconductor characteristics, can be controlled from a high resistance to a low resistance, and has a work function of 2.4 eV to 3.2 eV, which is approximately the same as that of an alkali metal. Therefore, it can preferably be used as the electron injection layer 312.

[0164] As the electron injection layer 312, Zn 0.7 Mg 0.3 O, Zn 0.75 Si 0.25 O, etc. can also be used. These metal oxides have semiconductor characteristics and can inject electrons into the light-emitting layer 314 because their work functions are as small as 3.1 eV. The band gaps of these metal oxides are also as large as 3.9 eV to 4.1 eV, so they can prevent holes from flowing into the electron transport layer 308 through the light-emitting layer 314. A ternary metal oxide semiconductor material formed by mixing two metal oxides, Zn 0.7 Mg 0.3 O and Zn 0.75 Si 0.25 O, in a range of 1:4 to 1:10 can also be used as the electron injection layer 312.

[0165] The electron injection layer 312 is formed by a film-forming apparatus 101. That is, a polycrystal of the electron compound C12A7 is used as a sputtering target 124 and formed in the first film-forming chamber 108a. The electron injection layer 312 formed of the electron compound C12A7 has a film thickness of 1 nm to 100 nm. The electron injection layer 312 of the electron compound C12A7 is formed of an amorphous thin film, but may also have crystallinity. Since the electron compound C12A7 is stable even in the atmosphere, it has the advantages of easy operation and can be formed by sputtering compared with alkali metal compounds such as lithium fluoride (LiF), lithium oxide (Li2O), sodium chloride (NaCl), and potassium chloride (KCl) that have been used as electron injection layers.

[0166] By using Zn 0.7 Mg 0.3 O, Zn 0.75 Si 0.25 O, etc. as the polycrystal of the sputtering target 124, and by using the sputtering method of inductively coupled plasma, the electron injection layer 312 can be formed. By using Zn 0.7 Mg 0.3 O and Zn 0.75 Si 0.25 O as the polycrystal of the ternary metal oxide material mixed in the range of 1:4 to 1:10 as the sputtering target 124, and by performing sputtering film formation in the film formation apparatus 100 using inductively coupled plasma, the electron injection layer 312 can be formed. The electron compound C12A7 is stable in the atmosphere but is easily soluble in water. Therefore, when used as a target material, moisture-proof measures are required during storage and management. In contrast, the polycrystal target material of the ternary metal oxide composed of Zn 0.7 Mg 0.3 O and Zn 0.75 Si 0.25 O mixed in the range of 1:4 to 1:10 is not easily soluble in water and is easy to store and manage.

[0167] The resistivity of Zn 0.7 Mg 0.3 O and Zn 0.75 Si 0.25 O used as the electron injection layer 312 is very high. Therefore, sputtering cannot be performed with a conventional DC magnetron sputtering apparatus. It is also possible to consider using an AC dual magnetron sputtering apparatus in which the sputtering target is divided into two and sputtering is alternately performed on each target using an AC power supply. However, in order to increase the film density to improve the crystallization rate, the discharge pressure during sputtering must be 0.3 Pa or less. However, when the substrate size reaches G8.5 (2500 mm × 2200 mm) or more, it is difficult to perform stable discharge while maintaining in-plane uniformity at 0.3 Pa or less. In contrast, as shown in the present embodiment, in the method using inductively coupled plasma, a negative pulse voltage can be applied to the sputtering target 124 for film formation. Even if the pressure during sputtering film formation is increased to around 1.3 Pa, crystallization can be promoted and the film density can be increased.

[0168] Before forming the electron injection layer 312 in the first film formation chamber 108a, the substrate 200 formed to the electron transport layer 308 can be degassed in the pretreatment chamber 104. By performing pretreatment, impurities such as moisture entering the organic electroluminescent element 300 can be reduced.

[0169] After the electron injection layer 312 is formed in the first film formation chamber 108a, the substrate 200 returns to the horizontal state by the chuck mechanism 118 of the third transfer chamber 106c and is transferred to the third film formation chamber 108c by the fourth transfer chamber 106d. In the third film formation chamber 108c, the light-emitting layer 314 is formed by a vacuum vapor deposition method (and / or an electron beam vapor deposition method).

[0170] The light-emitting layer 314 is formed using a metal mask provided with through holes matching the arrangement of the opening portions 311. The light-emitting layer 314 is manufactured by a vacuum vapor deposition method using materials corresponding to each known light-emitting color. The film thickness of the light-emitting layer 314 is appropriately set, for example, to a film thickness of 10 nm to 100 nm. In the case where a white light-emitting layer is formed as the light-emitting layer 314, the light-emitting layer 314 can be formed over the entire surface of the element formation region without using a metal mask.

[0171] After the light-emitting layer 314 is formed, the substrate 200 is transferred to the fourth film formation chamber 108d by the fourth transfer chamber 106d, and the hole transport layer 316 and the hole injection layer 318 are formed. The hole transport layer 316 is formed by a vacuum vapor deposition method (and / or an electron beam vapor deposition method) using known materials such as arylamine compounds, amine compounds containing a carbazolyl group, amine compounds containing a fluorene derivative, and the like. In addition, the hole injection layer 318 is formed by a vacuum vapor deposition method (and / or an electron beam vapor deposition method) using metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, or phthalocyanine-based materials such as copper phthalocyanine. For example, the hole transport layer 316 is formed to a film thickness of 10 nm to 500 nm, and the hole injection layer 318 is formed to a film thickness of 1 nm to 100 nm.

[0172] In the present embodiment, an example of forming the hole transport layer 316 and the hole injection layer 318 in the same film formation chamber is shown. However, not limited to this example, the film formation apparatus 101 may include more film formation chambers, and may be formed in a film formation chamber different from the hole transport layer 316 and the hole injection layer 318.

[0173] After the hole transport layer 316 and the hole injection layer 318 are formed, the substrate 200 is transferred to the fourth film formation chamber 108d by the fourth transfer chamber 106d, and the second electrode (anode) 320 is formed. The second electrode (anode) 320 is formed of a metal film such as aluminum (Al), or a laminate of a transparent conductive film such as ITO or IZO and a metal film such as aluminum (Al). Such a second electrode (anode) 320 is manufactured by a vacuum vapor deposition method (and / or an electron beam vapor deposition method) in the fourth film formation chamber 108d.

[0174] As described above, the organic electroluminescent element 300 can be manufactured by the film forming apparatus 101. In the film forming apparatus 101, a chamber for sputtering film formation based on inductively coupled plasma and a chamber for film formation by vacuum vapor deposition (and / or electron beam vapor deposition) are connected by a transfer chamber 106, so that the electron injection layer 312, the light emitting layer 314, the hole transport layer 316, the hole injection layer 318, and the second electrode (anode) 320 can be continuously deposited in a vacuum. By using the film forming apparatus 101 having such a structure, an organic electroluminescent element 300 with excellent reproducibility and high reliability and a display panel having the organic electroluminescent element 300 can be manufactured.

[0175] Explanation of Reference Numerals

[0176] 100: Film forming apparatus, 101: Film forming apparatus, 102: Loading / unloading chamber, 104: Pretreatment chamber, 106; Transfer chamber, 108: Film forming chamber, 109: Chamber wall, 110: Vacuum exhaust system, 111: Evaporation source, 112: Gas supply system, 114: Substrate stage, 115: High-frequency discharge electrode, 116: Transfer robot, 118: Chuck mechanism, 120: High-frequency power supply, 122: AC power supply, 123: Pulse power supply, 124: Sputtering target, 126: Antenna for generating inductively coupled plasma, 127: Heater, 128: Through hole, 130: Backplane, 131: Bonding material, 132: Target material, 134: Shielding plate, 136: Insulating member, 138: Gas introduction pipe, 140: Plasma diffusion prevention plate, 141: Anti-deposition plate, 142: First surface, 143: Second surface, 144: First opening, 146: Insulating member, 147: Glass layer, 148: Antenna body for generating inductively coupled plasma, 150: Metal tube, 151: Conductive layer, 152: Capacitor, 153: O-ring, 154: Second opening, 156: Coil, 160: Transfer tray, 162: Pin, 164: Lifting mechanism, 166: Gas introduction pipe, 168: High-frequency discharge plasma, 170: Grid, 172: Hollow tube, 174: Conductive layer, 176: Variable capacitor, 180: Ceramic member, 200: Substrate, 202: Surface, 204: Antenna connection area, 210: First insulating layer, 218: Second insulating layer, 220: Gate electrode, 230: Transistor, 300: Organic electroluminescent element, 302: Carrier injection amount control electrode, 304: First insulating layer, 306: First electrode (cathode), 308: Electron transport layer, 310: Second insulating layer, 311: Opening, 312: Electron injection layer, 314: Light emitting layer, 316: Hole transport layer, 318: Hole injection layer, 320: Second electrode (anode)

Claims

1. A film forming apparatus, comprising: A film forming chamber, in which a sputtering target having a rectangular shape in a plan view is installed; A plasma diffusion prevention plate, which covers the sputtering target and has an opening at a position overlapping with the surface of the sputtering target; A gas introduction pipe, which is provided in a region surrounded by the plasma diffusion prevention plate and is used to introduce gas into the film forming chamber; An insulating member, which is located inside the region surrounded by the plasma diffusion prevention plate, adjacent to the sputtering target, and protrudes toward the inside of the film forming chamber, has a U-shaped groove shape in a cross-sectional view, and separates the internal space of the film forming chamber from the atmosphere side; And A rod-shaped antenna for generating inductively coupled plasma, which is located in the region surrounded by the plasma diffusion prevention plate, adjacent to the sputtering target, and is disposed in the groove portion of the U-shaped groove shape of the insulating member protruding toward the inside of the film forming chamber; Wherein, the insulating member is provided with a glass layer on its surface and is inserted into a through hole provided in the film forming chamber from the atmosphere side; The rod-shaped antenna does not contact the insulating member but is arranged on the atmosphere side; and The plasma diffusion prevention plate is covered with a material having a secondary electron emission rate greater than 1.

2. The film forming apparatus according to claim 1, wherein, The insulating member having a U-shaped groove shape and the rod-shaped antenna are arranged along the longitudinal direction of the sputtering target.

3. The film forming apparatus according to claim 1, wherein, The rod-shaped antenna includes a first antenna disposed on one side of the sputtering target and a second antenna disposed on the other side of the sputtering target, and the first antenna and the second antenna are separated and arranged in parallel.

4. The film forming apparatus according to claim 1, wherein, The rod-shaped antenna includes a first antenna disposed on one side of the sputtering target and a second antenna disposed on the other side of the sputtering target; A high-frequency power of 13.56 MHz or 27 MHz and an alternating voltage having a frequency overlapping with the high-frequency power and ranging from 10 kHz to 1000 kHz are applied to the first antenna and the second antenna, and a pulse voltage in the range of -100 V to -600 V is applied to the sputtering target when the alternating voltage becomes 0 V.

5. The film forming apparatus according to claim 1, wherein, The gas introduction pipe is formed of a pipe made of an insulating ceramic porous body and is arranged along the longitudinal direction of the sputtering target.

6. The film forming apparatus according to claim 1, wherein, The plasma diffusion prevention plate has a first surface parallel to the surface of the sputtering target and a second surface perpendicular to the surface of the sputtering target, The first surface is provided with the opening, and a plurality of slit-shaped openings having a width narrower than the opening are provided from the second surface to the first surface; The plurality of slit-shaped openings extend elongated in a direction intersecting with the length direction of the rod-shaped antenna.

7. The film forming apparatus according to claim 1, wherein, The insulating member is made of a ceramic material selected from alumina, yttrium oxide (Y2O3), forsterite (Mg2SiO4), and talc (MgO·SiO2).

8. The film forming apparatus according to claim 1, wherein, The rod antenna is composed of a plurality of rod antennas, and the plurality of rod antennas are connected in series by capacitors and arranged on the atmosphere side of the insulating member.

9. The film forming apparatus according to claim 1, wherein The plasma diffusion prevention plate is made of a magnesium alloy, a barium alloy or a calcium alloy mainly composed of aluminum, and an anodic oxidation film is formed on the surface of the plasma diffusion prevention plate.

10. The film forming apparatus according to claim 1, further comprising: A pretreatment chamber for removing adsorbed molecules on the surface of a substrate to be subjected to sputtering film formation by plasma discharge before sputtering film formation is performed in the film forming chamber; And A transfer chamber for connecting the film forming chamber and the pretreatment chamber.

11. The film forming apparatus according to claim 10, wherein The pretreatment chamber includes a plurality of insulating pins for lifting the substrate in a horizontal state and holding it in a horizontal state, and a first electrode and a second electrode for generating inductively coupled plasma; Nitrogen gas, oxygen gas or nitrous oxide gas is introduced into the pretreatment chamber, and plasma discharge occurs, so that the entire surface of the substrate including the front surface, the back surface and the side surfaces is exposed to the plasma discharge for degassing treatment while the substrate is lifted in a horizontal state.

12. The film forming apparatus according to claim 1, wherein The chamber wall of the portion of the film forming chamber provided with the sputtering target and the insulating member having a U-shaped groove shape are formed of the same ceramic member and constructed as an integrated chamber wall.

13. The film forming apparatus according to claim 3, wherein The chamber wall of the portion of the film forming chamber provided with the sputtering target and the insulating member having a U-shaped groove shape corresponding to the first antenna and the second antenna are made of a ceramic material selected from alumina, yttrium oxide (Y2O3), forsterite (Mg2SiO4) and talc (MgO·SiO2) and constructed as an integral member.

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