CN115735268A

CN115735268A - Film forming apparatus for performing sputtering film formation by inductively coupled plasma

Info

Publication number: CN115735268A
Application number: CN202180044881.5A
Authority: CN
Inventors: 田中荣
Original assignee: Mikuni Electron Co Ltd
Current assignee: Mikuni Electron Co Ltd
Priority date: 2020-06-23
Filing date: 2021-06-22
Publication date: 2023-03-03
Also published as: WO2021261484A1; KR20230008774A; JPWO2021261484A1

Abstract

A film forming apparatus includes a film forming chamber in which a sputtering target is mounted, a plasma diffusion preventing plate covering the sputtering target and having an opening at a position overlapping with a surface of the sputtering target, an antenna for discharge provided adjacent to the sputtering target and protruding toward an inner side of a region surrounded by the plasma diffusion preventing plate, and a gas introduction pipe provided inside the plasma diffusion preventing plate and introducing gas into the film forming chamber. The antenna has an insulating member having a U-shaped groove shape protruding to the inside of the plasma diffusion prevention plate, and an antenna body arranged on the atmospheric side of the insulating member, wherein the antenna body can protrude from the sputtering target surface to the inside of the film forming chamber.

Description

Film forming apparatus for performing sputtering film formation by inductively coupled plasma

Technical Field

One embodiment of the present invention relates to a film formation apparatus using Inductively Coupled Plasma (ICP).

Background

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

As a sputtering apparatus, a magnetron system is known in which a magnetron is disposed on the rear surface of a sputtering target, and a sputtering apparatus using Inductively Coupled Plasma (ICP) is also disclosed (for example, see patent document 1). An antenna structure for generating inductively coupled plasma is also disclosed (see patent document 2).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-065299

Patent document 2: japanese patent laid-open publication No. 2016-072168

Disclosure of Invention

Technical problem to be solved by the invention

In the magnetron sputtering method, the magnetic field (magnetic field intensity) generated by the magnet is not uniform, and the erosion of the sputtering target is not uniform, so that the effective utilization rate of the target material is low, and nodules are likely to occur. In addition, since the magnetic field concentrates the plasma locally, the target is easily subjected to thermal stress, and there is a problem that the target is easily cracked.

In addition, when a metal film is formed by magnetron sputtering, if the magnetic field intensity generated by the magnet is strong, the density of the deposited film can be increased. However, when an oxide material is formed into a film (for example, an oxide semiconductor film and an oxide conductive film), oxygen is decomposed only in a region having a strong magnetic field strength in the vicinity of a sputtering target, and unreacted oxygen molecules (O) are generated ₂ ) Adsorbed on the deposition surface and absorbed into the film in the state of oxygen molecules, thereby causing a problem of a decrease in the density of the deposited film.

Further, in the conventional sputtering apparatus using Inductively Coupled Plasma (ICP), in order to efficiently generate inductively coupled plasma, an antenna main body and an insulator cylindrical tube covering an antenna are arranged inside a film forming chamber, but in a case of coping with an increase in size as the film forming chamber is larger than 3 meters, it becomes very difficult to stably hold the antenna main body and the insulator cylindrical tube covering the antenna.

In the Inductively Coupled Plasma (ICP) sputtering apparatus disclosed in patent document 1, the generated inductively coupled plasma spreads over the entire inside of the film forming chamber, and the plasma cannot be confined in the vicinity of the sputtering target as in the magnetron sputtering apparatus. Therefore, compared with the magnetron sputtering apparatus, there is moisture (H) adsorbed on the inner wall of the film forming chamber ₂ O), oxygen (O) ₂ ) And a coating layer in which hydrocarbons are released from the inner wall of the film forming chamber in a large amount at the start of film formation and easily enter the film formation. In order to increase the plasma density in the vicinity of the sputtering target, the amount of the contaminant gas released from the inner wall of the film forming chamber is increased by increasing the current flowing to the antenna body, which in turn causes a decrease in the reproducibility of the film quality of the deposited film.

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.

Means for solving the problems

A film deposition apparatus according to an embodiment of the present invention includes: the plasma processing apparatus includes a film forming chamber provided with a sputtering target, a plasma diffusion preventing plate covering the sputtering target and provided with an opening at a position overlapping with a surface of the sputtering target, an antenna provided adjacent to the sputtering target and protruding toward an inner side of a region surrounded by the plasma diffusion preventing plate for generating inductively coupled plasma, and a gas introduction pipe provided inside the plasma diffusion preventing plate for introducing gas into the film forming chamber, wherein a negative pulse voltage is applied to the sputtering target.

ADVANTAGEOUS EFFECTS OF INVENTION

According to one embodiment of the present invention, the plasma diffusion prevention plate is provided to cover the antenna for generating the 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 forming chamber, and impurities can be prevented from entering the film to be formed. Further, since the plasma density in the vicinity of the sputtering target can be increased, the sputtering rate can also be increased.

Drawings

Fig. 1 shows an overall configuration of a film deposition apparatus according to an embodiment of the present invention.

Fig. 2 is a diagram showing a configuration of a film forming apparatus according to an embodiment of the present invention, and shows main components provided in or connected to a pretreatment chamber, a transfer chamber, and a film forming chamber other than a loading/unloading chamber.

Fig. 3 is a schematic partial cross-sectional view of a deposition chamber of a deposition apparatus according to an embodiment of the present invention, as viewed from the top.

Fig. 4 shows a detailed cross-sectional structure of an antenna for generating inductively coupled plasma used in a film deposition apparatus according to an embodiment of the present invention.

Fig. 5 shows a detailed cross-sectional structure of an antenna for generating inductively coupled plasma used in a film deposition apparatus according to an embodiment of the present invention.

Fig. 6 is a schematic view of a plasma diffusion preventing plate provided in a film forming chamber of a film forming apparatus according to an embodiment of the present invention, as viewed from the front.

Fig. 7 is a schematic view of a plasma diffusion preventing plate provided in a film forming chamber of a film forming apparatus according to an embodiment of the present invention, as viewed from the front.

Fig. 8A is a diagram illustrating the influence of an antenna for generating inductively coupled plasma provided in a film forming chamber on the surface of a substrate, showing a case where a plasma diffusion preventing plate is not provided.

Fig. 8B is a diagram illustrating an influence of an antenna for generating inductively coupled plasma provided in a film forming chamber on a surface of a substrate, showing a case where a plasma diffusion preventing plate is provided.

Fig. 9 is a diagram illustrating an influence of an antenna for generating an inductively coupled plasma provided in a film forming chamber on a surface of a substrate, and is a diagram illustrating a problem of non-uniformity of a deposited film that may occur without a plasma diffusion preventing plate.

Fig. 10A shows an example of a film formation target mounted on a film formation apparatus according to an embodiment of the present invention, and shows a case where two kinds of target materials are used.

Fig. 10B shows an example of a film formation target mounted on the film formation apparatus according to the embodiment of the present invention, and shows a case where three kinds of target materials are used.

Fig. 11 is a diagram showing a configuration of an antenna for generating inductively coupled plasma provided in a film forming chamber of a film forming apparatus according to an embodiment of the present invention.

Fig. 12 shows a cross-sectional structure of an antenna connection region of an antenna main body of an antenna for generating inductively coupled plasma used in a film deposition apparatus according to an embodiment of the present invention.

Fig. 13 is a diagram showing waveforms of an ac voltage applied to an antenna for generating inductively coupled plasma provided in a film deposition chamber of a film deposition apparatus according to an embodiment of the present invention and a pulse voltage applied to a film deposition target.

Fig. 14 schematically shows the relationship between the target voltage and the film density when an InGaZnO film is formed as an oxide semiconductor film.

Fig. 15 is a schematic cross-sectional view showing the structure of a pretreatment chamber of a film forming apparatus according to an embodiment of the present invention.

Fig. 16A is a front view of an antenna for generating inductively coupled plasma provided in a film deposition chamber of a film deposition apparatus according to an embodiment of the present invention.

Fig. 16B is a cross-sectional view of an antenna for generating inductively coupled plasma provided in a film forming chamber of a film forming apparatus according to an embodiment of the present invention, and shows a cross-sectional structure corresponding to a portion between A1 and A2 shown in fig. 16A.

Fig. 17A is a front view of an antenna for generating inductively coupled plasma provided in a film deposition chamber of a film deposition apparatus according to an embodiment of the present invention.

Fig. 17B is a cross-sectional view of an antenna for generating inductively coupled plasma provided in a film forming chamber of a film forming apparatus according to an embodiment of the present invention, and shows a cross-sectional structure corresponding to a portion between B1 and B2 shown in fig. 17A.

Fig. 18A shows an example of an element manufactured by using the film formation device according to the embodiment of the present invention.

Fig. 18B shows a detailed structure of an oxide semiconductor layer in an element manufactured by using the film formation apparatus according to the embodiment of the present invention.

Fig. 18C shows a detailed structure of an oxide semiconductor layer in an element manufactured by using the film formation apparatus according to the embodiment of the present invention.

Fig. 19 shows an overall configuration of a film deposition apparatus according to an embodiment of the present invention.

Fig. 20 is a diagram showing a configuration of a film forming apparatus according to an embodiment of the present invention, and shows main components provided in or connected to a pretreatment chamber, a transfer chamber, and a film forming chamber other than a loading/unloading chamber.

Fig. 21 shows an example of an element manufactured by using the film formation device according to the embodiment of the present invention.

Fig. 22A is a schematic partial cross-sectional view of a film forming chamber of a film forming apparatus according to an embodiment of the present invention, as viewed from the top surface.

FIG. 22B shows a front view of a ceramic member used in the film forming chamber shown in FIG. 22A.

Fig. 23A is a schematic partial cross-sectional view of a film forming chamber of a film forming apparatus according to an embodiment of the present invention, as viewed from the top surface.

FIG. 23B shows a front view of a ceramic member used in the film forming chamber shown in FIG. 23A.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings and the like. The invention, however, comprises many different aspects and is not to be construed as being limited to the embodiments exemplified below. For the sake of clarity, the drawings attached 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 the present invention, when a specific element shown in one drawing is identical to or corresponds to a specific element shown in another drawing, the specific element may be denoted by the same reference numeral (or a reference numeral such as a or b is added to a reference numeral shown as a reference numeral), and redundant description thereof may be appropriately omitted. In addition, the words "first" and "second" attached to each element are used as a convenient label for distinguishing between the elements, and do not mean anything more unless otherwise specified.

In this specification, when one member or region is located "on (or under)" another member or region, unless otherwise specified, this includes not only the case where it is located directly above (or under) another member or region but also the case where it is located above (or under) another member or region. Also included is a case where another component is included between the upper side (or lower side) of another component or region and a certain component or region.

First embodiment

Fig. 1 shows an overall configuration of a film deposition apparatus 100 for performing sputtering film deposition according to an embodiment of the present invention. The film forming apparatus 100 includes a loading/unloading chamber 102 for storing a substrate before film formation 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 platen mechanism 118, and a first film forming chamber 108a and a second film forming chamber 108b for performing sputter film formation. These chambers are connected by a gate valve, and a vacuum exhaust device not shown is provided.

The substrate on which the thin film is formed is stored in the loading/unloading chamber 102 in a state of being held in a cassette. The substrate is, for example, a glass substrate. The substrate received in the loading/unloading chamber 106 is carried to the pre-processing chamber 104 by a carrier robot 116 provided on the first carrier chamber 102 a. The pretreatment chamber 104 pretreats the substrate on which the thin film is formed. The pretreatment chamber 104 includes a high-frequency discharge electrode connected to a high-frequency power supply 120. As the pretreatment, the substrate is degassed by a stage provided with a heating mechanism and high-frequency discharge plasma generated by a high-frequency discharge electrode. Fig. 1 shows a state where two pretreatment chambers 104 are provided with the first transfer chamber 106a therebetween, but the number of pretreatment chambers 104 is not limited. As shown in fig. 1, when two pretreatment chambers 104 are provided in the film forming apparatus 100, it is possible to continuously perform sputter film formation with sufficient time while sufficiently performing the degassing process. The film forming apparatus 100 is not limited to the form shown in fig. 1, and the number of the pretreatment chambers 104 may be one, or may be three or more.

The substrate pretreated by the pretreatment chamber 104 is carried to the second carrier chamber 106b by the carrier robot 116. The substrate is carried from the loading/unloading chamber 102 to the pre-processing chamber 104 in a horizontal state. The second transfer chamber 106b includes a platen mechanism 118, and stands up in a vertical state or in a state of being inclined from the vertical by about 20 degrees so that the substrate carried in a horizontal state is held by a transfer carrier not shown in fig. 1.

The first film formation chamber 108a and the second film formation chamber 108b are provided with an antenna 126 for generating inductively coupled plasma, and a sputtering target 124 is mounted. 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 an antenna 126 for generating inductively coupled plasma. The pulsed power supply 123 is connected to the sputtering target 124 and is capable of controlling the acceleration energy of the ions. In the film formation apparatus 100, the density of the thin film deposited on the substrate can be controlled by this mechanism.

In the first film forming chamber 108a and the second film forming chamber 108b, sputtering targets 124 of different materials (composition, density) can be installed, and thin films of different compositions can be successively deposited in vacuum. In addition, the sputtering targets 124 of the same kind (composition, density) can be installed in the first film forming chamber 108a and the second film forming chamber 108b, so that thin films of different film qualities can be deposited by applying different film forming conditions. Fig. 1 shows two film forming chambers 108, but the film forming apparatus 100 is not limited to such a structure, and the number of film forming chambers 108 may be appropriately changed according to the structure and type of a thin film to be produced. The film forming apparatus 100 may be configured such that, for example, when a single-layer thin film is formed, the number of film forming chambers 108 is one, and when a plurality of thin films are formed, three or more film forming chambers 108 are connected.

Fig. 2 is a diagram showing the configuration of the film forming apparatus 100, and shows 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, except for the loading/unloading chamber. A vacuum exhaust system 110 is connected to each chamber. The vacuum exhaust system 110 is constituted by vacuum pumps such as a Turbo Molecular Pump (TMP) and a dry pump (DRP). The first and

second transfer chambers

106a and 106b and the first and second

film formation chambers

108a and 108b may have different or the same vacuum exhaust system 110. The first film forming chamber 108a and the second film forming chamber 108b may be provided with a conduction valve for pressure control. 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 constituted by a mass flow controller, a filter, and the like.

The pre-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.

Between the pretreatment chamber 104 and the first film forming chamber 108a, the apparatus is provided with a first conveyance chamber 106a of a conveyance robot 116 and a second conveyance chamber 106b provided with a platen mechanism 118. The substrate subjected to the desorption process of adsorbed molecules in the pretreatment chamber 104 is transferred to the first film formation chamber 108a via the first transfer chamber 106a and the second transfer chamber 106b without being in contact with the atmosphere. The substrate pretreated by the pretreatment chamber 104 is transferred to the second transfer chamber 106b by the transfer robot 116 of the first transfer chamber 106 a. The transfer robot 116 transfers the substrate while keeping the substrate horizontal. The substrate transferred to the second transfer chamber 106b is vertically or obliquely inclined in a range of 20 degrees from the vertical direction by the platen mechanism 118, and is transferred to the first film forming chamber 108a.

It is considered that film formation by sputtering is preferable to form a film with the substrate standing upright rather than horizontal, in order to avoid the formation of pinholes in the deposited film. However, for example, in a display application, the size of a substrate becomes large (for example, 2200mm × 2400mm in the eighth generation glass substrate of a liquid crystal process), and the substrate is bent by its own weight, so that it is difficult to always convey the substrate in a vertically upright state. Further, in an apparatus for forming a film while keeping a substrate horizontal, such as a cluster-type single-wafer sputtering apparatus, there is a problem that the size of the substrate increases and the footprint of the apparatus increases (that is, the footprint of a clean room increases). In order to solve such a problem, the film deposition apparatus 100 is provided with the platen mechanism 118 in the middle of the substrate conveyance path, and processes the substrate horizontally until the early stage of film deposition, and performs the substrate in a state of standing in a vertical state or being inclined by about 20 degrees from the vertical at the film deposition stage, so that the substrate processing becomes easy. Further, the film formation apparatus 100 has an advantage that the floor space required for installation can be reduced.

The first film forming chamber 108a is provided with an antenna 126 for generating inductively coupled plasma, and is mounted with a sputtering target 124. An antenna 126 for generating inductively coupled plasma is connected to the high frequency power supply 120 outputting a high frequency in the megahertz band. In addition, the ac power supply 122 may be connected to enable application of ac voltage in the kilohertz band so that the antenna 126 for generating inductively coupled plasma overlaps with high frequency power. The pulsed 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 be provided.

Although 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 fig. 2, the first film formation chamber 108a and the second film formation chamber 108b are provided with a transfer mechanism for transferring the substrate in a state of being vertical or inclined from the vertical by about 20 degrees.

Fig. 3 is a schematic partial cross-sectional view of the film forming chamber 108 (the first film forming chamber 108a and the second film forming chamber 108 b) as viewed from the top surface. The film forming chamber 108 is configured to form a closed space whose inner space is isolated from the atmosphere, and fig. 3 shows a schematic structure between two wall surfaces (a first chamber wall 109a and a second chamber wall 109 b).

The film formation chamber 108 includes a plasma diffusion preventing plate 140 provided to cover the sputtering target 124, antennas 126 (a first antenna 126a and a second antenna 126 b) provided to protrude toward a region surrounded by the plasma diffusion preventing plate 140 and used for generating inductively coupled plasma, and a gas introduction pipe 138 for introducing a sputtering gas. The film deposition apparatus 100 is used with the sputtering target 124 installed in the film deposition chamber 108, however, the sputtering target 124 can be said to be a consumable part, and is not fixed to a component of the film deposition apparatus 100, but is an accessory part that is appropriately replaced. Although members such as the sputtering target 124 and the antenna 126 for generating inductively coupled plasma are attached to the film forming chamber 108, sealing members such as O-rings and gaskets are attached to the attached portion of each member.

The sputtering target 124 includes a target material 132 and a backing plate 130. The target 132 is bonded to the backing plate 130 formed of a metal such as copper (Cu), titanium (Ti), or the like with a bonding material such as an indium alloy or the like. The target 132 is preferably an integrally formed product. The sputtering target 124 is mounted on the first chamber wall 109a of the film forming chamber 108. The first through hole 128a is provided in the first chamber wall 109a, and the sputtering target 124 is attached so that the backing plate 130 fits into the first through hole 128a. To bias the sputtering target 124, an insulating member 136 is disposed between the backing plate 130 and the first chamber wall 109 a.

The sputtering target 124 is rectangular when viewed from the front and has a length direction parallel to the vertical direction. The target 132 may mount various sputterable materials. For example, as the target 132, a sintered body of metal oxide for forming a transparent conductive film and an oxide semiconductor film can be applied. The target 132 is increased in temperature due to ion collision during sputter film formation. Therefore, the film formation apparatus 100 is provided with a mechanism for cooling the backing plate 130 to suppress a temperature rise of the target 132. As an example thereof, fig. 3 shows a structure in which water flow holes through which cooling water flows are provided in the back plate 130.

In the case where the sputtering target 124 is mounted on the first chamber wall 109a, the target material 132 is exposed to the inner space of the film forming chamber 108. The film forming chamber 108 is provided with a shield plate 134 to cover the peripheral edge portion of the target 132. The shield plate 134 covers the surface of the back plate 130 in the region exposed between the target 132 and the first chamber wall 109 a. With this structure, the backplate 130 can be protected from being sputtered by exposure to inductively coupled plasma.

The film forming chamber 108 is provided with antennas 126 (a first antenna 126a and a second antenna 126 b) for generating inductively coupled plasma. The antenna 126 for generating inductively coupled plasma is arranged to sandwich the sputtering target 124 in the longitudinal direction of the sputtering target 124. That is, the first antenna 126a and the second antenna 126b as the antenna 126 for generating the inductively coupled plasma are arranged so as to sandwich the sputtering target 124.

The first antenna 126a and the second antenna 126b, which are the antennas 126 for generating the inductively coupled plasma, include an antenna main body 148 (a first antenna main body 148a, a second antenna main body 148 b) for generating the inductively coupled plasma and an insulating member 146 (a first insulating member 146a, a second insulating member 146 b) 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 146 b. The antenna 126 for generating inductively coupled plasma is provided 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 providing the antenna main body 148 for generating inductively coupled plasma in the insulating member 146, it is possible to prevent the substance sputtered from the target 132 from adhering to the antenna main body 148 for generating inductively coupled plasma. In addition, the antenna body 148 for generating the inductively coupled plasma can be not exposed to the inductively coupled plasma.

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 132 (a position near the center in the film forming chamber 108 or a position on the substrate 200 side). For example, the antenna body 148 for generating inductively coupled plasma is provided to protrude from the surface of the target 132 by a length D2. As described above, by providing the antenna body 148 for generating inductively coupled plasma protruding from the surface of the target 132, the plasma density at the surface of the target 132 can be increased.

Fig. 22A shows another structure of the film forming chambers 108 (the first film forming chamber 108a, the second film forming chamber 108 b). Fig. 22A is a partially schematic sectional view of the film forming chamber 108 as seen from above in the same manner as in fig. 3. The film forming chamber 108 shown in fig. 22A has a structure in which the antenna 126 (the first antenna 126a and the second antenna 126 b) for generating inductively coupled plasma and a part of the first chamber wall 109a on which the sputtering target 124 is mounted are formed of a ceramic member 180 a. Fig. 22B shows a front view of the ceramic member 180 a.

As shown in fig. 22A and 22B, the ceramic member 180a is provided with a first through hole 128a to which the sputtering target 124 is attached. Since the ceramic member 180a has an insulating property, the sputtering target 124 can be directly attached. That is, when the sputtering target 124 is attached to the film forming chamber 108, the insulating member 136 shown in fig. 3 may be omitted. The ceramic member 180a is provided with a second through hole 128b for mounting the antenna 126 (the first antenna 126a and the second antenna 126 b) for generating inductively coupled plasma. The U-shaped groove-shaped insulating member 146 (first insulating member 146a, second insulating member 146 b) is inserted through the second through hole 128b, and is vacuum-sealed by an O-ring on the back surface side of the ceramic member 180 a. Further, since the ceramic member 180a is insulating, the shield plate 134 covering the peripheral edge portion of the target 132 can be integrated.

Fig. 23A shows a structure in which, in the film forming chamber 108 (the first film forming chamber 108a, the second film forming chamber 108 b), the insulating member 146 (the first insulating member 146a, the second insulating member 146 b) having a U-shaped groove shape covering the antenna main body 148 (the first antenna main body 148a, the second antenna main body 148 b) for generating the inductively coupled plasma is integrated with the ceramic member 180b in a part of the first chamber wall 109 a. Fig. 23B also shows a front view of the ceramic member 180B. As shown in fig. 23A and 23B, the insulating member 146 (first insulating member 146a, second insulating member 146B) formed in a U-shaped groove shape is integrally formed with a part of the first chamber wall 109a, whereby the number of parts can be reduced and leakage (hermetic leakage of vacuum) can be prevented. A glass layer may be formed on the atmosphere side (the side where the antenna main body 148 for generating inductively coupled plasma is provided) of the portion of the ceramic member 180b corresponding to the insulating member (the first insulating member 146a and the second insulating member 146 b) formed in the U-shaped groove shape. The provision of the glass layer can further reduce leakage from the atmosphere side.

The

ceramic members

180a and 180b are excellent in insulation properties, have a high heat resistance temperature, a small thermal expansion coefficient, can be precisely processed, and have a small gas emission amount, and thus can be suitably used as a wall material of the film forming chamber 108. By using the

ceramic members

180a and 180b as a wall material near the antenna 126 for generating the inductively coupled plasma, the power loss of the antenna 126 for generating the inductively coupled plasma can be reduced. As a result, the plasma density near the surface of the target 132 can be increased.

As shown in fig. 22A and 23A, by forming the first chamber wall 109a on which the sputtering target 124 is mounted with the

ceramic members

180a and 180b, the amount of outgassing from the chamber inner wall can be reduced, and the plasma density can be increased. Further, since the peripheral portion of the target 132 is formed of the

ceramic members

180a and 180b as insulating members, the generation region of the vertical electric field with respect to the surface of the target 132 can be enlarged, and a film with higher density can be manufactured.

Fig. 4 shows a detailed sectional structure of the antenna 126 for generating inductively coupled plasma. The antenna body 148 for generating the inductively coupled plasma is formed of a hollow metal tube 150. For example, the antenna body 148 for generating the inductively coupled plasma is formed of a hollow metal tube 150 such as copper (Cu), brass, aluminum (Al), or the like. The antenna main body 148 for generating inductively coupled plasma is formed of such a metal pipe as a rod antenna, and cooling water flows through the hollow portion. A conductive layer 151 formed of a plated film of nickel (Ni) or tin (Sn) is preferably formed on the inner side surface of the metal pipe 150 to prevent corrosion. The insulating member 146 is made of quartz, alumina, or yttria (Y) ₂ O ₃ ) Forsterite (Mg) ₂ SiO ₄ ) Talc (MgO. SiO) ₂ ) And the like. The insulating member 146 is a U-shaped groove-shaped member in which an antenna body 148 for generating inductively coupled plasma is disposed, and is disposed to separate vacuum from the atmosphere. Preferably, a glass layer 147 is provided on the surface (particularly, the surface on the atmosphere side) of the insulating member 146 to increase airtightness (prevent leakage). An antenna body 148 for generating inductively coupled plasma is disposed on the atmosphere side by passing through the insulating member 146. Thus, by will be used forThe antenna main body 148 generating the inductively coupled plasma is disposed on the atmosphere side, the accuracy of the arrangement position thereof can be improved, and the uniformity of the plasma density in the vicinity of the target 132 can be improved. In addition, the holding mechanism of the antenna main body 148 for generating the inductively coupled plasma can also be freely designed.

In addition, as shown in fig. 5, the antenna 126 for generating the inductively coupled plasma may be composed of a plurality of antenna bodies 148 for generating the inductively coupled plasma. That is, the antenna body 148 for generating inductively coupled plasma may be composed of a plurality of antenna bodies 148 for generating inductively coupled plasma, and disposed on the atmosphere side of the insulating member 146. In the metal pipe 150 constituting the antenna main body 148 for generating inductively coupled plasma, the ac resistance increases with an increase in frequency due to the skin effect. For example, in the case where a high-frequency power of 13.56MHz is applied to the antenna body 148 for generating the inductively coupled plasma, even if the wall thickness of the metal pipe 150 is 5mm, the current flows only in a region of a depth of about 17.7 μm from the surface of the metal pipe 150. In order to prevent power loss due to the skin effect, as shown in fig. 5, the antenna 126 for generating the inductively coupled plasma may be configured with a plurality of antenna bodies 148 for generating the inductively coupled plasma in parallel.

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

The plasma diffusion prevention plate 140 is provided to surround the region where the sputtering target 124 is arranged. The plasma diffusion prevention plate 140 is a box-shaped member provided 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 face 142 substantially parallel to the face of the first chamber wall 109a and a second face 143 facing the first chamber wall 109a from the first face 142. Further, in the region surrounded by the plasma diffusion prevention plate 140, a landing plate 141 is provided so as to cover the surface of the first chamber wall 109 a. A first opening 144 is provided on the first surface 142 of the plasma diffusion preventing plate 140. The first opening 144 is provided at a position overlapping the target 132.

Fig. 6 shows a schematic configuration diagram when the plasma diffusion prevention plate 140 is viewed from the front. The sputtering target 124 is disposed in a region surrounded by the plasma diffusion prevention plate 140. When the sputtering target 124 is viewed from the front, the target material 132 is exposed from the first opening 144 of the plasma diffusion preventing plate 140.

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

The plasma diffusion prevention plate 140 is provided with a slit-shaped second opening 154 extending from the second surface 143 to the first surface 142. The second opening 154 is elongated and extends in a direction intersecting the longitudinal direction of the antenna 126 for generating inductively coupled plasma, and a plurality of openings are provided. The second opening 154 is a nozzle hole for the sputtering gas, and has 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 opening 154 has a function of controlling the conductance of the gas flow so that the sputtering gas stays in the space surrounded by the plasma diffusion prevention plate 140 for a predetermined time, and a uniform gas pressure is formed in the film formation region. The slit-shaped second opening 154 has a function of preventing an induced current from being generated in the plasma diffusion prevention plate 140 by the antenna 126 for generating inductively coupled plasma, and can improve the efficiency of energy transfer from the antenna 126 for generating inductively coupled plasma to inductively coupled plasma.

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 containing aluminum. Further, it is preferable that, in the plasma diffusion prevention plate 140 formed of these metal materials, the inner side surface facing the sputtering target 124 is anodized. The secondary electron emission ratio can be greater than 1 by forming an anodized film of a magnesium alloy, a barium alloy, or a calcium alloy on the inner side surface of the plasma diffusion prevention plate 140. Therefore, the surface of the anodized film has positive electric resistance, and argon ions (positive ions) can be prevented from being incident and colliding to the plasma diffusion prevention plate 140. That is, the argon ion (positive ion) sputtering plasma diffusion prevention plate 140 can be prevented, and the impurities entering into the thin film formed in the film forming chamber 108 can be reduced.

In the case where the carrier concentration of the n-type oxide semiconductor film is accurately controlled by sputtering, it is necessary to prevent impurities that generate an electron-killing effect from being mixed. As a countermeasure, it is preferable that the inner side surface of the plasma diffusion prevention plate 140 exposed to the inductively coupled plasma is covered with an insulating film that does not produce an electron killing effect. As the insulating film not causing the electron-killing effect, for example, silicon oxide (SiO) is exemplified ₂ ) Magnesium oxide (MgO), aluminum oxide (Al) ₂ O ₃ ). In particular, magnesium oxide (MgO) having a high secondary electron emission rate is preferable as the insulating film, and silicon oxide, aluminum oxide, or the like containing magnesium oxide (MgO) covers the surface of the plasma diffusion prevention plate 140.

The plasma diffusion preventing plate 140 is provided to prevent the inductively coupled plasma formed by the antenna 126 for generating the inductively coupled plasma from diffusing into the entire film forming chamber 108. By forming a physical wall called a plasma diffusion prevention plate 140, it is possible to prevent the inductively coupled plasma from being unnecessarily diffused in the film forming chamber 108. That is, the film forming chamber 108 has the following structure: the inductively coupled plasma is generated in the region surrounded by the plasma diffusion preventing plate 140 and the landing preventing plate 141, and does not diffuse to other regions. The plasma diffusion preventing plate 140 and the plasma attachment preventing plate 141 may have an anodic oxide film formed on the surface thereof, which may improve the plasma confinement effect and the plasma density.

In a conventional magnetron sputtering apparatus, in order to increase the film density of oxide semiconductor film formation, it is required to keep the gas pressure at the time of film formation at 0.5Pa or less. In addition, attention is paid not only to the impurity gas released from the inner wall of the film forming chamber but also to the fact that the components inside the film forming chamber are sputtered and enter the film as impurities.

Since the catalyst is formed by InGaSnO _x Since oxide semiconductors typically have n-type conductivity, when a film forming chamber is made of a stainless material containing iron (Fe), chromium (Cr), manganese (Mn), or the like, which has a large electron killing effect, it is necessary to completely prevent the chamber wall from coming into contact with plasma. When the oxide semiconductor film is formed, if water (H) adsorbed on the surface of the substrate is not performed ₂ O), hydrocarbons, etc., the film density does not increase, and a reliable thin film transistor cannot be manufactured.

Even before the surface of the substrate is degassed and conveyed to the film forming chamber, if the substrate temperature is not kept above 150 ℃, the moisture (H) in the vacuum chamber ₂ O) will be adsorbed again, and reproducibility cannot be improved. In addition, in order to increase the film density of the oxide semiconductor film which is still formed, it is necessary to increase the substrate temperature to 200 ℃ or more to increase the crystallization rate. By applying a sputtering gas (Ar + O) ₂ ) Adding trace hydrogen (H) ₂ ) Contamination of impurity gas released from the inner wall of the film forming chamber can be reduced, and heat treatment after film formation can be omitted. The heat treatment temperature of the thin film transistor after the element is completed can be reduced to about 200 ℃, so the manufacturing cost is greatly reduced.

Since the film forming chamber 108 has a structure in which inductively coupled plasma is blocked by the plasma diffusion preventing plate 140 and the plasma shielding plate 141, impurities (moisture (H) adsorbed on the chamber walls 109 (the first chamber wall 109a, the second chamber wall 109b, and the like) can be prevented from being adsorbed on the chamber walls 109 (the first chamber wall 109a, the second chamber wall 109b, and the like) ₂ O), hydrogen (H) ₂ ) Hydrocarbon, etc.) is absorbed by the thin film deposited on the substrate. Even if made of stainless steel (SUS 304)The film forming chamber 108 can also prevent contamination problems caused by iron (Fe), chromium (Cr), and the like.

As shown in fig. 7, a mesh 170 may be provided in the first opening 144. By providing the mesh 170, the confinement effect of the inductively coupled plasma can be improved. The mesh 170 is preferably formed of a metal material having no electron killing effect. For example, the mesh 170 is preferably formed of a metal material selected from titanium (Ti), tungsten (W), nickel (Ni), tantalum (Ta). Therefore, the diffusion of plasma into the film forming chamber 108 can be reliably prevented, and when the oxide semiconductor film is deposited, entry of an impurity serving as an electron-killing substance into the film can be prevented. By providing the mesh 170, negative oxygen ions are easily vertically incident on the substrate 200, and crystallization of the film-formed oxide semiconductor film can be promoted.

The opening ratio of the mesh 170 is preferably 70% or more. As shown in fig. 7, the wires (or mesh pattern) forming the mesh 170 are arranged to be inclined and crossed in 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 mesh 170 can be prevented from being transferred onto the film to be formed.

In addition, the plasma diffusion prevention plate 140 is preferably provided so as to be interposed between the antenna 126 (the first antenna 126a, the second antenna 126 b) for generating inductively coupled plasma and the substrate 200. If the plasma diffusion preventing plate 140 is not present, there is a problem that the antenna 126 (the first antenna 126a, the second antenna 126 b) for generating inductively coupled plasma affects the film quality of the thin film deposited on the substrate 200, as shown in fig. 8A. That is, since the surface 202 of the substrate 200 close to the antenna 126 (the first antenna 126a, the second antenna 126 b) for generating the inductively coupled plasma is affected by the self-bias of the antenna 126 (the first antenna 126a, the second antenna 126 b) for generating the inductively coupled plasma, the film quality of the deposited thin film is greatly different. In contrast, as shown in fig. 8B, when the plasma diffusion preventing plate 140 is provided between the antenna 126 (the first antenna 126a and the second antenna 126B) for generating the inductively coupled plasma and the substrate 200, the influence of the self-bias is shielded, and thus the film quality of the thin film deposited on the substrate 200 can be kept constant. Further, the antenna 126 for generating inductively coupled plasma is a connection region (a region where two conductors are capacitively coupled, which will be described in detail later), and by having the plasma diffusion preventing plate 140, the problem of non-uniformity of plasma can be solved.

In addition, in the case where 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 shown in fig. 9, there is a problem that the film quality of the region overlapping with the capacitor 152 (the first capacitor 152a, the second capacitor 152 b) connected to the metal tube 150 (the first metal tube 150a and the second metal tube 150b, the third metal tube 150c, and the fourth metal tube 150 d) constituting the antenna main body 148 for generating the inductively coupled plasma is different.

That is, in the case where the plasma diffusion preventing plate 140 is not provided, the plasma density of the portions of the first capacitor 152a and the second capacitor 152b provided in the first antenna 126a and the second antenna 126b, respectively, is different, and the film quality of the thin film deposited on the antenna connection region 204 overlapping with the portions is affected, so that a uniform thin film cannot be formed over the entire surface of the substrate 200. In contrast to this, in the case where the plasma diffusion prevention plate 140 is provided, there is no region corresponding to the antenna connection region 204, and the influence of the plasma unevenness is eliminated, so that a uniform film can be formed over the entire surface of the substrate 200.

The film deposition apparatus 100 is a moving deposition method, and as shown in fig. 3, a substrate 200 is mounted on a transfer tray 160 and transferred in front of a sputtering target 124. The substrate 200 is carried at a position close to the plasma diffusion preventing plate 140. As shown in fig. 3, 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 conveyance tray 160 are disposed so that the distance D3 is equal to or less than 1/5 of the distance D1. For example, if the distance D1 is 55mm, the spacing D3 has a length of 5 mm.

Thus, by carrying the substrate 200 close to the plasma diffusion preventing plate 140In this position, the conductance of the sputtering gas supplied to the region surrounded by the plasma diffusion prevention plate 140 when it flows out into the film forming chamber 108 through the first opening 144 can be reduced. In addition, this structure has a function of preventing impurities (moisture (H) from being adsorbed on the chamber wall 109 ₂ O), hydrogen (H) ₂ ) Hydrocarbon, etc.) to diffuse into the film forming region, and can exhibit an effect of improving reproducibility of physical properties of the film formed.

Fig. 10A and 10B show an example of a sputtering target 124 applied to the shift deposition method. Fig. 10A shows a structure in which two targets 132 (a first target 132a and a second target 132 b) are fixed to the backing plate 130 with a bonding material 131. Indium or an indium alloy is used as the bonding material 131.

The first target 132a and the second target 132b are made of a combination of materials having different compositions or materials. For example, when the target is an oxide semiconductor, a ternary oxide semiconductor target containing indium (In), gallium (Ga), and tin (Sn) is used as the first target 132a, and an oxide semiconductor target having a higher gallium (Ga) concentration than the first target 132a is used as the second target 132 b. In this way, two kinds of targets are arranged in the substrate conveying direction, and two layers having different compositions can be successively deposited.

The first target 132a and the second target 132b are disposed on the back plate 130 at a predetermined interval to prevent damage due to thermal expansion. The gap G1 is about 0.5 mm. In this case, the end portions of the first target 130a and the second target 131b in cross section are formed in a tapered shape so that the support plate 132 or the bonding material 132 is not exposed at the space portion. Specifically, as shown in fig. 10A, the first target 132a is formed as a tapered surface whose upper surface side end portion protrudes with respect to the bottom surface that is in contact with the bonding material 131, and the second target 132b is formed as a tapered surface whose bottom surface protrudes with respect to the upper surface side. By disposing the first target material 132a and the second target material 132b so that the two tapered surfaces are engaged with each other, the backing plate 130 and the bonding material 131 are not exposed when the sputtering target 124 is viewed in a plan view. That is, even if two kinds of targets are arranged on one back plate 130, the back plate 130 and the bonding material 131 can be prevented from sputtering in the boundary area, so that impurities can be prevented from entering the deposited film.

In the film forming chamber 108, the substrate 200 is conveyed forward of the sputtering target 124 at a constant speed in one direction, and therefore, the thickness of the deposited thin film can be varied by reducing the width of the second target 132b with respect to the first target 132 a. For example, by reducing the width of the second target 132b with respect to the width of the first target 132a, the thickness of the thin film deposited by the first target 132a can be increased, and the thickness of the thin film deposited by the second target 132b can be decreased.

Fig. 10B shows an example in which three kinds of targets 132 (a first target 132a, a third target 132c, and a second target 132B) are arranged. In this case, as in the example shown in fig. 10A, the side end portions of the targets adjacent to each other are shaped into a tapered shape. Specifically, the third target 132c sandwiched between the first target 132a and the second target 132b has a trapezoidal sectional shape. By disposing the first target 132a and the second target 132b having the opposite tapered surfaces from both sides of the third target 132c having such a cross-sectional shape, the sputtering target 124 has a structure in which the backing plate 130 and the bonding material 131 are not exposed in a plan view.

Fig. 11 shows details of the antenna 126 (first antenna 126a, second antenna 126 b) for generating inductively coupled plasma. 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 main body 148a is a rod antenna in which the first metal tube 150a and the second metal tube 150b are connected by the first capacitor 152a formed on the antenna connection region 204, and the second antenna main body 148b is a rod antenna in which the third metal tube 150c and the fourth metal tube 150d are connected by the second capacitor 152b formed on the antenna connection region 204. The first antenna main body 148a and the second antenna main body 148b have such a structure, and thus impedance can be reduced. Therefore, even in the case of extending the antenna body 148 for generating the inductively coupled plasma, it is possible to prevent an increase in impedance and to prevent a large potential difference from being generated between both ends of the antenna body 148 for generating the inductively coupled plasma. As a result, it is possible to cope with the increase in size of the sputtering target 124.

Fig. 12 shows a cross-sectional structure of the antenna connection region 204 of the antenna body 148 for generating inductively coupled plasma. The antenna connection region 204 has a structure in which the first metal tube 150a and the second metal tube 150b (or the third metal tube 150c and the fourth metal tube 150 d) are embedded in the hollow tube 172 formed of an insulating material. The hollow pipe 172 is provided with an O-ring 153 at a portion where the first metal pipe 150a and the second metal pipe 150b are fitted, and has a structure that maintains airtightness and prevents leakage even when cooling water flows. The O-ring 153 is preferably heat-resistant, and for example, a fluororubber-based one is used.

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

The conductive layer 174 is formed by disposing the hollow tube 172 made of an insulating material so as to face the first metal tube 150a and the second metal tube 150b, thereby forming the capacitor 152. That is, the first metal pipe 150a and the second metal pipe 150b are inserted into the hollow pipe 172 having the conductive layer 174 formed on the inner surface thereof to be capacitively coupled, thereby forming the antenna main body 148 for generating the inductively coupled plasma. In this way, by disposing the hollow tube 172 made of an insulating material on the inner peripheral portions of the first metal tube 150a and the second metal tube 150b, it is possible to reduce the unevenness of the antenna main body 148 for generating the inductively coupled plasma, and to uniformize the inductively coupled plasma.

In addition, since the antenna main body 148 for generating the inductively coupled plasma is disposed on the atmosphere side, the variable capacitor 176 may be disposed in parallel in the capacitor 152. Therefore, the impedance of the antenna body 148 for generating the inductively coupled plasma can be adjusted accurately or widely. Therefore, the antenna 126 for generating the inductively coupled plasma is easily matched with the high frequency power supply 120.

Further, in the antenna main body 148 for generating the 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, it is possible to prevent malfunction and destruction caused by heat generation of the capacitor 152, and to increase the power of the high-frequency power applied to the antenna 126 for generating the inductively coupled plasma.

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

The antenna main body 148 for generating the inductively coupled plasma is connected to the high frequency power source 120 having an oscillation frequency of 13.56MHz or 27 MHz. Specifically, the first antenna main body 148a is connected to the first high-frequency power supply 120a, and the second antenna main body 148b is connected to the second high-frequency power supply 120 b. The phases of the high frequency power outputted from the first high frequency power supply 120a and the second high frequency power supply 120b may be the same, but are preferably shifted by a half wavelength (180 degrees). Therefore, the plasma density at the surface of the target 132 can be increased. In addition, the first antenna body 148a is also connected to a first variable capacitor 158a, and the second antenna body 148b is connected to a second variable capacitor 158b. The variable capacitors 158 (the first variable capacitor 158a and the second variable capacitor 158 b) are provided to adjust the impedance of the antenna main bodies 148 (the first antenna main body 148a and the second antenna main body 148 b) for generating the inductively coupled plasma so as to easily match the impedance of the high-frequency power supply 120 (the first high-frequency power supply 120a and the second high-frequency power supply 120 b).

The antenna bodies 148 (the first antenna body 148a, the second antenna body 148 b) for generating the inductively coupled plasma are also connected to the ac power supply 122 having a frequency of 10kHz to 1000 kHz. A coil 156 for cutting off high frequency is inserted between the antenna main body 148 (first antenna main body 148a, second antenna main body 148 b) for generating inductively coupled plasma and the ac power supply 122. In addition to the high-frequency power, by applying an alternating voltage to the antenna bodies 148 (the first antenna body 148a, the second antenna body 148 b) for generating the inductively coupled plasma, the plasma density of the surface of the target 132 can be increased.

Further, by superimposing an alternating voltage on the high-frequency power, deposits (products sputtered from the target 132) adhering to the insulating member 146 can be removed by a sputtering phenomenon. Therefore, the change of the discharge characteristic with time can be suppressed. In particular, in the case of forming a transparent conductive film having a low resistance value, the circuit structure of the antenna 126 for generating inductively coupled plasma shown in fig. 11 exerts an advantageous effect in obtaining stable discharge. Note that in the case of forming an oxide semiconductor film having a high resistance value, even if deposits adhere to the insulating member 146, they are not significantly affected, and therefore the alternating-current power supply 122 is not necessary. On the other hand, when the distance between the first antenna 126a and the second antenna 126b is increased to 300mm or more, the plasma density in the central region of the sputtering target 124 is reduced, and therefore, the plasma density can be made uniform by applying an ac voltage between the first antenna main body 148a and the second antenna main body 148b using the ac power supply 122.

The pulsed power supply 123 is connected to the sputtering target 124. The pulsed power supply 123 applies a negative pulsed voltage of about-100V to-600V to the sputtering target 124. As shown in fig. 13, by applying a negative pulse voltage at a timing when an alternating voltage applied to the antenna main body 148 for generating inductively coupled plasma becomes 0V, it is possible to emit sputtered particles in a direction perpendicular to the substrate. Thus, a dense film can be deposited.

Fig. 14 schematically shows the relationship between the target voltage and the film density when an InGaZnO film as an oxide semiconductor film is formed by sputtering. The sputtering method using inductively coupled plasma has an advantage in that two power sources, a power source for generating and maintaining plasma and a power source for controlling sputtering 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 plasma becomes non-uniform, and stable discharge cannot be maintained.

In contrast, when inductively coupled plasma is used, if the high-frequency power applied to an antenna for generating 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 function of confining plasma in the vicinity of the sputtering target by the magnetic field of the magnet, the plasma can be uniformly brought into contact with the surface of the substrate. Therefore, the oxidation reaction of the metal and the oxygen atom can be promoted.

In the sputtering method using inductively coupled plasma, when forming an InGaZnO film, the voltage applied to the sputtering target is set to about-200V, whereby the crystal yield can be improved while minimizing damage to the film deposited on the substrate surface. At this time, the film density of the InGaZnO film can be 6.30g/cm ³ . The film density is close to the theoretical value 6.378g/cm ³ 。

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

Fig. 15 shows the structure of the pretreatment chamber 104. The pre-chamber 104 is provided with a substrate stage 114 and a high-frequency discharge electrode 115. The substrate stage 114 is provided with an elevating mechanism 164 for raising the substrate 200 placed thereon upward. Substrate table 114 has the function of: pins 162 that contact the substrate 200 are provided at a plurality of positions, and the pins 162 protrude upward by a lifting mechanism 164, thereby lifting the substrate 200 to a floating state.

The substrate stage 114 is formed of a conductor to serve as a ground electrode, and is at the same potential as the chamber wall of the pre-chamber 104. In the substrate stage 114, a heater for heating a substrate not shown may be built inA heat apparatus. 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 were connected to a high-frequency power supply 120 having an oscillation frequency of 13.56MHz or 27 MHz. The pretreatment chamber 104 is also provided with a gas introduction pipe 166. Nitrogen gas (N), for example, is introduced from gas introduction pipe 166 ₂ ) Gas, oxygen (O) ₂ ) Gas or nitrous oxide (N) ₂ O) gas as pretreatment gas. In addition, instead of the gas introduction pipe 166, a high-frequency discharge electrode 115 formed of a shower plate may be used, and gas may be introduced therefrom. The pressure at which plasma is generated during pretreatment is preferably 10Pa to 10Pa ³ Pa, in the range of Pa.

In the pretreatment chamber 104, when a pretreatment gas is introduced and a 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 becomes a steady 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 so as to go around not only the front surface but also the back surface side of the substrate 200. Therefore, not only molecules of impurities or contaminants such as moisture adsorbed on the surface of the substrate 200 (the surface on which the thin film is deposited) but also molecules adsorbed on the back surface and the side surfaces can be removed. Since the pin 162 is exposed to plasma, it is preferably formed of an insulating ceramic to prevent impurities from being released.

Heretofore, as a pretreatment of the substrate 200, plasma treatment has been performed in vacuum. However, the plasma treatment is usually performed only on the front surface side of the substrate 200, and is performed in a state where the back surface side is not exposed to plasma. In this state, even if the front surface of the substrate 200 is cleaned, moisture adsorbed on the back surface side remains, and therefore, even after the substrate 200 is conveyed to the film forming chamber, the substrate continues to be degassed from the back surface. In particular, when the gas pressure during sputtering film formation is low as in the case of forming an oxide semiconductor film, it is not sufficient to perform only the degassing treatment on the surface side of the substrate 200. As a result, no matter how high the film forming chamber is evacuated, molecules (moisture (H) are adsorbed ₂ O), hydrogen (H) ₂ ) Hydrocarbon, etc.) continue to be released from the back side of the substrate 200, thusThe film quality near the center and near the periphery of the substrate 200 is very different. For example, when the oxide semiconductor film is formed by a sputtering method, since a outgassing component emitted from the back surface of the substrate 200 cannot be controlled, carrier concentrations in the vicinity of the center and the vicinity of the periphery of the substrate 200 are greatly different. The larger the size of the substrate 200, the larger the problem.

As the degassing treatment of the substrate 200, heating at a temperature of 200 ℃ or higher in vacuum may be considered, but it takes several hours to completely remove adsorbed moisture, and it is not suitable for mass production. When film formation of the oxide semiconductor film is processed with a single wafer, it is not practical to perform heat treatment for several hours per substrate 200.

However, as shown in this embodiment, in the pretreatment chamber 104, by performing plasma treatment by floating the substrate 200, not only the front surface but also the back surface is exposed to plasma, so that degassing of the entire region can be performed, so that the entire substrate can be cleaned in a short time, and the carrier concentration can be accurately controlled.

In the film formation apparatus 100 for forming an oxide semiconductor film, it is important to forcibly degas an adsorbed component (moisture (H)) adsorbed on the entire surface of the substrate 200 by using nitrogen plasma and oxygen plasma before sputtering film formation ₂ O), hydrogen (H) ₂ ) Hydrocarbon). Therefore, a homogeneous oxide semiconductor film having a constant carrier concentration over the entire surface of the substrate 200 can be manufactured.

The film forming chamber 108 of the film forming apparatus 100 is preferably formed of a metal material with little outgassing. For example, when an oxide semiconductor film for forming a thin film transistor is formed, it is necessary to increase film density to improve reliability. In order to increase the film density, the sputtering pressure at the time of sputtering film formation needs to be about 0.1Pa to 1.5 Pa. In such a pressure range, since the inductively coupled plasma diffuses throughout the film forming chamber 108, the inner wall is exposed to the plasma. When positive ions in the plasma collide with the inner wall of the film forming chamber, adsorbed molecules such as moisture (H) ₂ O), hydrogen (H) ₂ ) And hydrocarbons, etc. are largely eliminated. These impurities affect the characteristics of a transistor formed using an oxide semiconductor filmFor the reason.

In consideration of strength, stainless steel is used for the film forming chamber 108 of the film forming apparatus 100 shown in the present embodiment. However, elements such as iron (Fe), molybdenum (Mo), manganese (Mn), and the like as stainless steel components are not preferable because they are electron-killing impurities for n-type oxide semiconductors. That is, when stainless steel is exposed in the film forming chamber 108, the characteristics of a transistor using an oxide semiconductor film are adversely affected. In a conventional sputtering apparatus, since stainless steel is always in an exposed state in a film forming chamber, the manufacturing yield of a transistor using an oxide semiconductor film is reduced, which is a factor of reducing process reproducibility.

In order to solve such a problem, the film forming apparatus 100 according to the present embodiment is configured to provide a plasma diffusion preventing plate 140 made of metal such as magnesium (Mg), aluminum (Al), titanium (Ti), tungsten (W), or nickel (Ni) in the film forming chamber 108 and to block plasma. In order to improve electron density and discharge stability in plasma, a film of an oxide of an alkaline earth metal such as magnesium oxide (MgO), barium oxide (BaO), strontium oxide (SrO), or calcium oxide (CaO) having a high secondary electron emission rate, or an insulating film containing silicon oxide, aluminum oxide, or yttrium oxide is provided on the surface of the plasma diffusion prevention plate 140.

As shown in fig. 1 and 2, the film formation apparatus 100 includes a first film formation chamber 108a and a second film formation chamber 108b. With such a structure of the first film formation chamber 108a and the second film formation chamber 108b, two kinds of oxide semiconductor films different in film quality can be stacked. 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.

For example, a target of an oxide semiconductor can be used in the first film forming chamber 108a, only argon (Ar) or argon (Ar) and oxygen (O) can be used ₂ ) The film formation is performed using argon (Ar) and oxygen (O) in the second film formation chamber 108b as sputtering gases ₂ ) (at this time, the oxygen partial pressure is higher than the condition in the first film forming chamber 108 a) film formation is performed. In the sputtering film formation of the oxide semiconductor film, increasing the oxygen partial pressure can increase the oxygen anionDensity, which can increase the irradiation density of oxygen anions to the film deposition surface. Thus, the oxide semiconductor film deposited in the second film formation chamber 108b can have a lower carrier density and higher crystallinity than the oxide semiconductor film deposited in the first film formation chamber 108a.

Further, by applying a negative pulse voltage to the sputtering target 124, negative ions of oxygen generated during discharge reach the deposition surface of the oxide semiconductor film during application of the pulse voltage, thereby promoting densification of the film and making it easy to crystallize. In the present embodiment, the antenna 126 for generating the inductively coupled plasma may generate a large amount of oxygen radicals, and since the metal element is more easily reacted with oxygen due to the inductively coupled plasma contacting or approaching the surface of the substrate 200, unreacted oxygen (O) may be reduced ₂ ) Probability of molecules entering the membrane.

As described above, the film formation apparatus 100 according to the present embodiment employs a mobile film formation system and has a structure in which the plurality of first film formation chambers 108a and the plurality of second film formation chambers 108b are connected in series, so that carrier concentration can be accurately controlled when an oxide semiconductor film is deposited. Note that although this embodiment mainly describes an example in which the oxide semiconductor film is manufactured by the film formation apparatus 100, the film formation apparatus 100 is not limited to this, and can also be applied to manufacturing a transparent conductive film, other semiconductor films, and a metal film.

In the present embodiment, as shown in the front view of fig. 16A and the cross-sectional view of fig. 16B (corresponding to the cross-sectional structure between A1 and A2 shown in fig. 16A), the first antenna 126A and the second antenna 126B are rod antennas extending substantially the same length in the same direction as the longitudinal direction of the sputtering target 124. In this example, the first insulating member 146a and the second insulating member 146b having U-shaped grooves are provided so as to protrude inward of 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 so as to be surrounded by the first insulating member 146a and the second insulating member 146b having U-shaped grooves.

However, the first antenna 126A and the second antenna 126B are not limited to the embodiments shown in fig. 16A and 16B, and the first antenna 126A and the second antenna 126B may be arranged in a plurality of U-shaped antenna sections. For example, as shown in the front view of fig. 17A and the cross-sectional view of fig. 17B (corresponding to the cross-sectional structure between B1-B2 shown in fig. 17A), the plurality of first antenna bodies 148a _1to 148a _3and the plurality of second antenna bodies 148b _1to 148b _3may be divided along the length direction of the sputtering target 124. By arranging the first antenna 126a and the second antenna 126b, the plasma density can be similarly increased, and a dense film can be deposited. In addition, fig. 17A and 17B show an embodiment in which the antenna main body 148 for generating the inductively coupled plasma is divided into three in the longitudinal direction of the sputtering target 124, but the number of the divided antenna main bodies 148 for generating the inductively coupled plasma is not limited in the first antenna 126a and the second antenna 126B for generating the inductively coupled plasma, and an antenna main body 148 for generating the inductively coupled plasma may be divided into three or more antennas for generating the inductively coupled plasma.

The present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the gist. In addition, the respective embodiments may be combined as appropriate.

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

In more detail, 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 first conductive layer 212a forming a source electrode and a first conductive layer 212b forming a drain electrode are provided in pairs. The first

conductive layers

212a and 212b are formed of a transparent conductive film such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), or the like. In order to reduce the resistance, second

conductive layers

214a and 214b made of a metal material such as aluminum (Al) may be provided over the first

conductive layers

212a and 212 b.

The oxide semiconductor layer 216 is formed so as to cover the first

conductive layers

212a and 212b (and the second

conductive layers

214a and 214 b). A second insulating layer 218 which is a gate insulating layer is provided over the oxide semiconductor layer 216, and a gate electrode 220 is provided thereover so as to overlap with the oxide semiconductor layer 216.

The oxide semiconductor layer 216 may be formed of a plurality of layers having different compositions and crystallinities. For example, as shown in fig. 18B, a structure in which a first oxide semiconductor layer 216a and a second oxide semiconductor layer 216B are stacked may be provided. 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 high proportion of gallium (Ga) relative to the first oxide semiconductor layer 216a and also has high crystallinity. The second oxide semiconductor layer 216b is formed thinner than the first oxide semiconductor layer 216 a. Since the concentration of gallium (Ga) is high, the second oxide semiconductor layer 216b has wider band gap and lower carrier concentration than the first oxide semiconductor layer 216 a. For example, the first oxide semiconductor layer 216a is formed with a film thickness of 40nm to 60nm, and the second oxide semiconductor layer 216b is formed with a film thickness of about one tenth of 4nm to 6 nm.

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, that is, a so-called buried channel is formed in the first oxide semiconductor layer 216 a. That is, the transistor 230 can flow carriers through the channel region without being affected by defects formed on the interface between the second insulating layer 218 (gate insulating layer) and the oxide semiconductor layer 216. With such a structure, the transistor 230 can stabilize characteristics and reduce variations in characteristics.

As shown in fig. 18C, 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 216 b. The third oxide semiconductor layer 216c is a same ternary oxide semiconductor, but has a higher concentration of indium (In) than the first oxide semiconductor layer 216a and the second oxide semiconductor layer 216 b. By providing such a third oxide semiconductor layer 216c, the field-effect mobility of the transistor 230 can be improved.

According to the film formation device 100 of the present embodiment, the structure of the oxide semiconductor layer 216 shown in fig. 18B can be manufactured by using the sputtering target 124 shown in fig. 10A, and the structure of the oxide semiconductor layer 216 shown in fig. 18C can be manufactured by using the sputtering target 124 shown in fig. 10B. That is, oxide semiconductors having different compositions and different crystallinities can be formed continuously in vacuum.

The composite divided target shown in fig. 10A and 10B is likely to cause abnormal discharge in the divided portion and cannot be used in a conventional magnetron sputtering apparatus. On the other hand, in the system not using a magnet, since argon ions charged with a positive electrode are almost uniformly incident on the entire surface of the sputtering target, abnormal discharge hardly occurs. In addition, since the entire surface of the sputtering target is uniformly sputtered, heat generation on the surface of the sputtering target is also uniformly generated. Therefore, cracks are not easily generated by the thermal stress of the sputtering target.

InGaSnO capable of producing oxide semiconductor film having high electron mobility _x In the conventional magnetron sputtering apparatus, since fine cracks called hairline cracks are easily generated in the sputtering target, the target cannot be used in a mass production factory. In contrast, in the film deposition apparatus 100 according to the present embodiment, since a magnet is not used, plasma is not locally concentrated and local heat generation is not generated. Therefore, hair cracks caused by thermal stress are also difficult to occur.

As in the film forming apparatus 100 according to the present embodiment, the plasma diffusion prevention plate 140 prevents the Inductively Coupled Plasma (ICP) from diffusing to the entire internal region of the film forming chamber 108, and thus film formation can be performed without reducing the deposition rate even in a moving film forming method in which sputtering film formation is performed while moving a substrate.

Further, 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. Further, since the negative oxygen ions can be made to perpendicularly enter the substrate 200, even if the film formation gas pressure is close to 1.5Pa, the film density can be prevented from decreasing. For example, an eleventh generation glass substrate (3000 mm × 3320 mm) can also deposit an oxide semiconductor film with high mobility and high reliability by increasing the film density.

It is to be noted that the structure of the transistor 230 shown in fig. 18A is one example, and the film formation device 100 relating to the present embodiment mode can be used to manufacture oxide semiconductor transistors having various structures, whether it is a top gate type or a bottom gate type.

Second embodiment

This embodiment mode shows an example of a film formation apparatus capable of performing sputtering and vacuum vapor deposition (and/or electron beam vapor deposition) continuously using inductively coupled plasma. The film formation device described in this embodiment mode can be applied to, for example, manufacturing of an organic electroluminescence element (or an organic electroluminescence display device). Hereinafter, a description will be given mainly on the differences from the film formation apparatus 100 according to the first embodiment.

Fig. 19 shows an overall configuration of a film deposition apparatus 101 according to the present embodiment. The film forming apparatus 101 includes: a loading/unloading chamber 102 for storing substrates before and after film formation, a pretreatment chamber 104 for pretreating substrates, a first transfer chamber 106a provided with a transfer robot 116, a second transfer chamber 106b provided with a platen mechanism 118, a first film formation chamber 108a for performing sputter film formation, a third transfer chamber 106c provided with a platen mechanism 118, a fourth transfer chamber 106d provided with a transfer robot 116, a third film formation chamber 108c provided with an evaporation source 111, a fourth film formation chamber 108d, and a fifth film formation chamber 108e. These chambers are connected by a gate valve, and a vacuum exhaust device not shown is provided.

The pretreatment chamber 104, the first transfer chamber 106a, the second transfer chamber 106b, the third transfer chamber 106c, and the fourth transfer chamber 106d have the same structures as those of the first embodiment. The first film formation chamber 108a is a chamber for performing sputtering film formation by inductively coupled plasma, and performs film formation of an 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 forming organic films such as a light emitting layer and a hole transporting layer, which will be described later. The fifth film forming chamber 106e is a chamber provided with an evaporation source 111 and is configured to form a film of an anode, which will be described later, by a vacuum vapor deposition method (and/or an electron beam vapor deposition method).

In the film formation apparatus 101 shown in fig. 19, a chamber for performing sputtering film formation by inductively coupled plasma and a chamber for performing film formation by a vacuum vapor deposition method (and/or an electron beam vapor deposition method) are connected via a transfer chamber, and an inorganic film and an organic film can be continuously deposited in vacuum. Further, by providing the second transfer chamber 106b and the third transfer chamber 106c to which the platen mechanism 118 is attached, with the first film formation chamber 108a for forming a sputtering film by inductively coupled plasma interposed therebetween, the sputtering film formation can be performed in a state in which the substrate 200 is vertical or inclined by about 20 degrees from the vertical, and in a film formation by a vacuum vapor deposition method (and/or an electron beam vapor deposition method), the substrate 200 can be kept substantially horizontal.

Note that the number of chambers in which film formation is performed by the vacuum vapor deposition method (and/or the electron beam vapor deposition method) is arbitrary, and may be appropriately connected depending on the number of layers of the vapor deposition film, the type of film.

Fig. 20 is a diagram showing the configuration of the film forming apparatus 101, and shows main components provided or connected to the pretreatment chamber 104, the first conveyance chamber 106a, the second conveyance chamber 106b, the first film forming chamber 108a, the third conveyance chamber 106c, the fourth conveyance chamber 106d, and the third film forming chamber 108c, except for the loading/unloading chamber 102. The other chambers except for the third film forming chamber 108c are configured in the same manner as in the first embodiment.

In the third film formation chamber 108c in which film formation is performed by a vacuum vapor deposition method (and/or an electron beam vapor deposition method), a cryopump is added as the vacuum exhaust system 110 in addition to the turbo molecular pump and the dry pump. By implementing high vacuum exhaust through these vacuum exhaust systems 110, moisture remaining in the chamber can be effectively removed. Film formation by vacuum vapor deposition may be performed by a moving deposition method in which a substrate is moved in front of a linear evaporation source 111, or may be performed by a scanning film formation method in which the evaporation source 111 is moved to scan the surface of the substrate.

The film deposition apparatus 101 can be applied to substrates of various sizes because it employs a moving deposition method for film deposition by a sputtering method and film deposition by a vacuum vapor deposition method (and/or an electron beam vapor deposition method). For example, the film forming apparatus 101 can be used to form an eleventh generation glass substrate (3000 mm × 3320 mm).

Fig. 21 shows an example of an element manufactured using the film formation apparatus 101. The element shown in fig. 21 shows a cross-sectional structure of the organic electroluminescence element 300. The organic electroluminescent element 300 has the following structure, which is stacked on the substrate 200: the light-emitting device includes 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 in which an opening 311 is formed, 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. 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 a region where the opening 311 is provided.

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 to the light emitting layer 314 via the electron injection layer 312 and the light emitting position in the light emitting layer 314 by applying a positive bias voltage. Since the organic electroluminescent element 300 is of a bottom emission type, the carrier injection amount controlling electrode 302 is formed of a transparent conductive film.

The electron transport layer 308 has a two-layer structure. The first electron transport layer 308a is provided over the first insulating layer 304 in a larger area than the carrier injection amount controlling electrode 302. The first electrode (cathode) 306 is provided outside the opening 311 (in a region overlapping with the second insulating layer 310). The first electrode (cathode) 306 may be formed, for example, in a double-layer structure of a first conductive layer 306a and a second conductive layer 306b, and an end portion 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 of ITO, IZO, or the like, and has a function of forming ohmic contact with the electron transport layer 308 and injecting electrons. The second conductive layer 306b is provided as appropriate for lowering the resistance of the first electrode (cathode) 306.

The first electron transport layer 308a is formed of a metal oxide having semiconductor characteristics. As such a metal oxide, in can be used ₂ O ₃ -Ga ₂ O ₃ -SnO ₂ -ZnO-based oxide material, in ₂ O ₃ -Ga ₂ O ₃ -SnO ₂ Oxide-based material, in ₂ O ₃ -SnO ₂ -ZnO-based oxide material, in ₂ O ₃ -Al ₂ O ₃ -ZnO-based oxide material, ga ₂ O ₃ -SnO ₂ -ZnO-based oxide material, ga ₂ O ₃ -Al ₂ O ₃ -ZnO-based oxide material, snO ₂ -Al ₂ O ₃ -ZnO-based oxide material, in ₂ O ₃ -ZnO-based oxide material, snO ₂ -ZnO-based oxide material, al ₂ O ₃ -ZnO-based oxide material, ga ₂ O ₃ -SnO ₂ Oxide-based material, ga ₂ O ₃ -ZnO-based oxide material, ga ₂ O ₃ -MgO-based oxide material, mgO-ZnO-based oxide material, snO ₂ -MgO-based oxide material, in ₂ O ₃ -MgO-based oxide material, in ₂ O ₃ Oxide-based material, ga ₂ O ₃ Metal oxide material, snO ₂ Metal oxide-based materials, znO-based metal oxide materials, and the like. The first electron transport layer 308a can be formed by a sputtering method using the film formation apparatus 100 described in the first embodiment.

A second insulating layer 310 is disposed on the first electron transport layer 308 a. An opening 311 for exposing the surface of the first electron transport layer 308a is provided in the second insulating layer 310. The second electron transport layer 308b is formed of a metal oxide material having the same semiconductor characteristics as the first electron transport layer 308 a. The second electron transport layer 308b may be formed by a sputtering method or may be formed in the region of the opening 311 by an application method.

At this time, the second insulating layer 310 is preferably formed of an insulating film having polarity. Such a second insulating layer 310 may be formed using a linear fluorine-containing organic material. As the linear fluoro-organic material, for example, a Fluoroalkylsilane (FAS) -based material is used. As the Fluoroalkylsilane (FAS) material, H,1H, 2H-perfluorodecyltrichlorosilane (FDTS), tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS), and the like can be used, for example. The second insulating layer 310 is formed using a linear fluorine organic material, thereby forming a surface having hydrophobicity. An opening 311 is formed in the second insulating layer 310. The second insulating layer 310 exhibits high hydrophobicity on the surface, and the sidewall surface of the opening 311 is hydrophilic compared to the surface.

When the second electron transporting layer 308b is manufactured by a coating method, a composition solution containing the quaternary oxide layer material, the ternary oxide layer material, the binary oxide layer material, the monovalent oxide layer material, or a precursor thereof is coated on the second insulating layer 310 in which the opening 311 is formed, and is dried and sintered. Specifically, zinc oxide (ZnO) is doped with a trivalent metal element such as aluminum (Al), indium (In), or gallium (Ga), 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, a coating film is selectively formed on the opening part 311 by appropriately adjusting the viscosity of the composition to be coated. The second electron transport layer 308b after firing has hydrophilicity due to the side wall surface of the opening 311, and the contact surface with the second insulating layer 310 rises upward, and has a cross-sectional shape having a gently tapered inclined surface as it goes inward. The average film thickness of the second electron transport layer 308b may be 200nm or more, and preferably 400nm or more. By providing the second electron transport layer 308b with such a thickness, short-circuit defects in the organic electroluminescent element 300 can be drastically reduced, and the yield can be improved.

The organic electroluminescent element 300 can divide a light-emitting region by providing the second insulating layer 310 having the opening 311 formed to expose the upper surface of the first electron transport layer 308a before the light-emitting layer 314 is formed. Further, since the end portion of the second electron transport layer 308b provided in the opening 311 has a tapered cross-sectional shape gently inclined from the wall surface of the opening 311, the step coverage (step coverage) of the electron injection layer 312 and the light-emitting layer 314 formed in the next stage can be improved.

The electron injection layer 312 is made of a material having a small work function 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 or aluminum (Al) oxide. As an example, the electron injection layer 312 is made of an electron compound C12A7 (12 Ca.7 Al) ₂ O ₃ ) And (4) forming. The electron compound C12A7 has semiconductor characteristics, can be controlled from high resistance to low resistance, has a work function of 2.4eV to 3.2eV, and is substantially the same as that of an alkali metal, and thus can be preferably used as the electron injection layer 312.

As the electron injection layer 312, zn may be used _0.7 Mg _0.3 O、Zn _0.75 Si _0.25 O, and the like. These metal oxides have semiconductor characteristics, and have a work function as small as 3.1eV, and therefore can inject electrons into the light-emitting layer 314. These metal oxides also have a band gap as large as 3.9eV to 4.1eV, and therefore can prevent holes from flowing into the electron transport layer 308 through the light emitting layer 314. Zn may also be used _0.7 Mg _0.3 O and Zn _0.75 Si _0.25 A ternary system metal oxide semiconductor material in which two kinds of metal oxides, O, are mixed in a range of 1: 4 to 1: 10 is used as the electron injection layer 312.

The electron injection layer 312 is formed by the film forming apparatus 101. That is, a polycrystalline body of the electronic compound C12A7 is used as the sputtering target 124, and the film is formed in the first film forming chamber 108a. The electron injection layer 312 formed by the electron compound C12A7 has a film thickness of 1nm to 100 nm. The electron injection layer 312 of the electron compound C12A7 is formed of an amorphous thin film, but may have crystallinity. Since the electronic compound C12A7 is stable even in the atmosphere, it is compatible with lithium fluoride (LiF) and lithium oxide (Li) which have been conventionally used as an electron injection layer ₂ Compared with alkali metal compounds such as O), sodium chloride (NaCl) and potassium chloride (KCl), the method has the advantages of simple operation and capability of forming a film by a sputtering method.

By using Zn _0.7 Mg _0.3 O、Zn _0.75 Si _0.25 A polycrystalline material such as O is used as the sputtering target 124, and the electron injection layer 312 can be formed by a sputtering method using inductively coupled plasma. By using a pump composed ofZn _0.7 Mg _0.3 O and Zn _0.75 Si _0.25 A polycrystalline body of a ternary metal oxide material in which O is mixed in a range of 1: 4 to 1: 10 is formed as the sputtering target 124, and sputtering film formation is performed in the film formation apparatus 100 using inductively coupled plasma, whereby the electron injection layer 312 can be formed. Since the electronic compound C12A7 is stable in the atmosphere but is easily soluble in water, moisture-proof measures are required for storage and management when used as a target material. In contrast, zn is substituted by _0.7 Mg _0.3 O and Zn _0.75 Si _0.25 The polycrystalline target material of ternary metal oxide in which O is mixed in the range of 1: 4 to 1: 10 is not easily dissolved in water and is easy to store and manage.

Zn used as the electron injection layer 312 _0.7 Mg _0.3 O and Zn _0.75 Si _0.25 Since the resistivity of O is very high, sputtering cannot be performed by a conventional DC magnetron sputtering apparatus. An AC dual magnetron sputtering apparatus may be used in which two sputtering targets are divided and sputtering is performed alternately on the respective targets using an AC power supply, but in order to increase the film density and increase the crystallization rate, the discharge pressure during sputtering needs to be 0.3Pa 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 of 0.3Pa or less. On the contrary, as shown in the present embodiment, in the mode using the inductively coupled plasma, the film can be formed by applying the negative pulse voltage to the sputtering target 124, and even if the pressure at the time of the sputtering film formation is increased to the vicinity of 1.3Pa, the crystallization can be promoted and the film density can be increased.

Before the electron injection layer 312 is formed in the first film formation chamber 108a, the substrate 200 formed to the electron transport layer 308 may be subjected to a degassing process in the pretreatment chamber 104. By performing the pretreatment, impurities such as moisture entering the organic electroluminescence element 300 can be reduced.

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

The light-emitting layer 314 is performed using a metal mask provided with a through hole matching the arrangement of the opening portion 311. The light emitting layer 314 is manufactured by a vacuum vapor deposition method using a material corresponding to each known light emitting color. The film thickness of the light-emitting layer 314 is appropriately set, and is formed to a film thickness of, for example, 10nm to 100 nm. In the case of forming a white light-emitting layer as the light-emitting layer 314, the light-emitting layer 314 may be formed over the entire surface of the element formation region without using a metal mask.

After the light-emitting layer 314 is formed, the substrate 200 is transported to the fourth film forming chamber 108d by the fourth transport 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 a known material, for example, an aromatic amine-based compound, an amine-based compound containing a carbazole group, an amine-based compound containing a fluorene derivative, or the like. The hole injection layer 318 is formed by a vacuum vapor deposition method (and/or an electron beam vapor deposition method) using a metal oxide such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, or manganese oxide, or a phthalocyanine-based material such as copper phthalocyanine. For example, the hole transport layer 316 is formed to have a film thickness of 10nm to 500nm, and the hole injection layer 318 is formed to have a film thickness of 1nm to 100 nm.

In this embodiment mode, an example in which the hole transport layer 316 and the hole injection layer 318 are formed in the same film forming chamber is shown. However, without being limited to this example, the film formation device 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.

After the formation of the hole transport layer 316 and the hole injection layer 318, the substrate 200 is transported to the fourth film formation chamber 108d via the fourth transport chamber 106d, and a 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 fabricated in the fourth film forming chamber 108d by a vacuum vapor deposition method (and/or an electron beam vapor deposition method).

As described above, the organic electroluminescent element 300 can be manufactured by the film formation device 101. In the film formation apparatus 101, a chamber in which sputtering film formation by inductively coupled plasma is performed and a chamber in which film formation is performed by a vacuum vapor deposition method (and/or an electron beam vapor deposition method) are connected by the transfer chamber 106, and 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 successively deposited in vacuum. By using the film formation device 101 having such a configuration, the organic electroluminescence element 300 having excellent reproducibility and high reliability and the display panel having the organic electroluminescence element 300 can be manufactured.

Description of the reference numerals

100: film forming apparatus, 101: film forming apparatus, 102: load/unload chamber, 104: a pre-treatment 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: platen mechanism, 120: high-frequency power supply, 122: ac power supply, 123: pulsed power supply, 124: sputtering target, 126: antenna for generating inductively coupled plasma, 127: heater, 128: through-hole, 130: back sheet, 131: bonding material, 132: target, 134: shield plate, 136: insulating member, 138 gas introduction pipe, 140 plasma diffusion preventing plate, 141 plasma prevention plate, 142: first surface, 143: second face, 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 portion, 156: coil, 160: conveyance tray, 162: pin, 164: elevating mechanism, 166: gas introduction pipe, 168: high-frequency discharge plasma, 170: grid, 172: hollow tube, 174: conductive layer, 176: variable capacitor, 180: ceramic part, 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 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 with a surface of the sputtering target;

an antenna for generating an inductively coupled plasma, disposed adjacent to the sputtering target and protruding to the inside of a region surrounded by the plasma diffusion prevention plate;

a gas introduction pipe provided inside the plasma diffusion prevention plate and configured to introduce a gas into the film forming chamber.

2. The film forming apparatus according to claim 1,

the antenna is provided with: an insulating member having a U-shaped groove protruding inward of the plasma diffusion prevention plate, and an antenna main body disposed on the atmosphere side of the insulating member.

3. The film forming apparatus according to claim 2,

the antenna main body protrudes from the surface of the sputtering target to the inside of the film forming chamber.

4. The film forming apparatus according to claim 3,

the sputtering target has a rectangular shape in a plan view,

the antenna is arranged along a longitudinal direction of the sputtering target.

5. The film forming apparatus according to any one of claims 1 to 4,

the 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.

6. The film forming apparatus according to any one of claims 1 to 5,

a high-frequency power and an alternating voltage superimposed on the high-frequency power are applied to the antenna.

7. The film forming apparatus according to claim 1,

the gas introduction pipe is formed of a porous material.

8. The film forming apparatus according to claim 1 or 7, wherein,

the sputtering target has a rectangular shape in a plan view,

the gas introduction pipe is arranged along a longitudinal direction of the sputtering target.

9. The film forming apparatus according to claim 1, wherein,

the plasma diffusion preventing plate has a first surface parallel to the surface of the sputtering target and a second surface facing the wall surface of the film forming chamber from the first surface,

the first surface is provided with the opening portion, and the second surface is provided with a slit having a width narrower than the opening portion.

10. The film forming apparatus according to claim 9, wherein,

the plasma diffusion prevention plate is formed of a material having a secondary electron emissivity greater than 1.

11. The film forming apparatus according to claim 2,

the insulating member is selected from quartz, alumina, and yttria (Y) ₂ O ₃ ) Forsterite (Mg) ₂ SiO ₄ ) And talc (MgO. SiO) ₂ ) One kind of (1).

12. The film forming apparatus according to claim 2, wherein,

the antenna main body includes a first metal tube and a second metal tube, and a capacitor that capacitively couples the first metal tube and the second metal tube,

the capacitor includes an insulating hollow tube in which the first metal tube and the second metal tube are embedded, and a conductive layer provided inside the hollow tube.

13. The film forming apparatus according to claim 2,

the antenna body is composed of a plurality of antenna bodies and is disposed on the atmospheric side of the insulating member.

14. The film forming apparatus according to claim 10, wherein,

the plasma diffusion prevention plate is a magnesium alloy, a barium alloy, or a calcium alloy mainly composed of aluminum, and an anodic oxide film is formed on the surface thereof.

15. The film forming apparatus according to claim 9, wherein,

a carrying tray for carrying the substrate is arranged in the film forming chamber,

the distance between the substrate mounted on the carrier tray and the first surface of the plasma diffusion prevention plate is narrower than the distance between the sputtering target and the plasma diffusion prevention plate.

16. The film forming apparatus according to claim 1,

and a pretreatment chamber for pretreating the substrate formed in the film forming chamber.

17. The film forming apparatus according to claim 16,

the pretreatment chamber includes a pin for lifting the substrate in a horizontal state, and a first electrode and a second electrode for generating inductively coupled plasma on the front surface side and the back surface side of the substrate.

18. The film forming apparatus according to claim 17, wherein,

the first electrode is provided on the surface side of the substrate.

19. The film forming apparatus according to claim 1,

the chamber wall of the film forming chamber in the portion where the sputtering target is provided is formed of a ceramic member.

20. The film forming apparatus according to claim 2,

the chamber wall of the film forming chamber in the portion where the sputtering target is provided and the insulating member having a U-shaped groove shape are formed of a ceramic member.