JP2008285715A - Vapor deposition boat and vapor deposition apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To deposit a thin film having excellent film thickness uniformity by an vapor deposition process. <P>SOLUTION: The vapor deposition boat EB is used for evaporating a vapor deposition material in an vapor deposition apparatus, and the vapor deposition boat is equipped with: a resistance heating element having in its upper face TS a recessed part RS formed by a nonmetallic material and to be supplied with the vapor deposition material; a pair of electrodes ED1 and ED2 arranged so as to sandwich the recessed part RS of the resistance heating element HR; and a coating body CB formed by a metallic material and arranged between the recessed part RS and at least either electrode ED1 in the upper face TS of the resistance heating element HR. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vapor deposition boat and a vapor deposition apparatus, and more particularly to a vapor deposition apparatus for forming a thin film constituting a display element and a vapor deposition boat provided in the vapor deposition apparatus.

Vapor deposition apparatuses are used to form various thin films such as organic layers and inorganic layers. For example, Patent Document 1 describes that a light emitting layer of an organic electroluminescence (EL) element is formed by a vapor deposition method.
JP 2003-157773 A

  By the way, when forming a metal layer by a vapor deposition method, a wire can be formed with a vapor deposition material. As a vapor deposition method using such a wire, there is a method in which a wire is supplied toward a vapor deposition boat for evaporating the vapor deposition material, and the vapor deposition material evaporated from the vapor deposition boat is vapor-deposited on an object to be processed.

  The objective of this invention is providing the vapor deposition apparatus which can form the thin film excellent in film thickness uniformity by the vapor deposition method, and the vapor deposition boat with which this vapor deposition apparatus is equipped.

The vapor deposition boat according to the first aspect of the present invention comprises:
A vapor deposition boat used to evaporate vapor deposition material in a vapor deposition apparatus,
A resistance heating element formed of a non-metallic material and provided with a recess on the upper surface to which a vapor deposition material is to be supplied;
A pair of electrodes arranged to sandwich the recess of the resistance heating element;
A covering formed of a metal material and disposed between the recess and at least one electrode on the upper surface of the resistance heating element;
It is provided with.

The vapor deposition apparatus according to the second aspect of the present invention comprises:
A vacuum chamber;
A vapor deposition boat disposed in the vacuum chamber for evaporating vapor deposition material;
A feeder for supplying a wire as a vapor deposition material to the vapor deposition boat;
A holder for holding an object to be deposited on the vapor deposition material evaporated from the vapor deposition boat in the vacuum chamber,
The vapor deposition boat is
A resistance heating element formed of a non-metallic material and provided with a recess on the upper surface to which a deposition material is to be supplied by the feeder;
A pair of electrodes arranged to sandwich the recess of the resistance heating element;
A covering body that is formed of a metal material and covers an upper surface of the resistance heating element that is between the recess and one of the electrodes and faces the wire supplied toward the recess;
It is provided with.

  According to the present invention, it is possible to provide a vapor deposition apparatus capable of forming a thin film having excellent film thickness uniformity by a vapor deposition method and a vapor deposition boat provided in the vapor deposition apparatus.

  Hereinafter, a vapor deposition boat and a vapor deposition apparatus according to an embodiment of the present invention will be described with reference to the drawings. In each figure, the same or similar components are denoted by the same reference numerals, and redundant description is omitted.

  First, an example of components of a flat display provided with a thin film that can be formed by the present vapor deposition apparatus will be described. Here, an organic EL element will be described particularly as a constituent element of a flat display.

  As shown in FIG. 7, the array substrate 100 constituting the organic EL display device includes a plurality of organic EL elements 40 arranged on the main surface side of the wiring substrate 120. The wiring board 120 includes a pixel switch, a driving transistor, a storage capacitor element, various wirings (scanning lines, signal lines, power supply lines, etc.) on an insulating support substrate such as a glass substrate or a plastic sheet. It shall be configured.

  The organic EL element 40 includes a first electrode 60 disposed on the wiring substrate 120, a second electrode 66 disposed to face the first electrode 60, and the first electrode 60 and the second electrode 66. And a photoactive layer 64 disposed therebetween.

  More specifically, the first electrode 60 is formed using a light-transmitting conductive material such as indium tin oxide (ITO) in the configuration employing the bottom emission type. Moreover, the 1st electrode 60 contains the reflection layer which has light reflectivity, such as aluminum (Al), in the structure which employ | adopted the top emission type. In this case, the first electrode 60 may be formed as a single layer having a function as an electrode and a function as a reflective layer using a light-reflective conductive material. A two-layer structure in which a transmissive layer formed using a reflective layer formed using a light-reflective material may be stacked.

  The photoactive layer 64 is disposed on the first electrode 60 and includes at least the light emitting layer 64A. The photoactive layer 64 can include functional layers other than the light emitting layer 64A. For example, the photoactive layer 64 includes functional layers such as a hole injection layer, a hole transport layer, a blocking layer, an electron transport layer, an electron injection layer, and a buffer layer. Can do. The photoactive layer 64 may be composed of a single layer in which a plurality of functional layers are combined, or may have a multilayer structure in which the functional layers are stacked. In the photoactive layer 64, the light emitting layer 64A may be an organic material, and layers other than the light emitting layer 64A may be an inorganic material or an organic material. The light emitting layer 64A is formed of an organic compound having a light emitting function that emits red, green, or blue light.

  The second electrode 66 is disposed on the photoactive layer 64. The second electrode 66 is formed using a light-transmitting conductive material such as ITO, magnesium (Mg), silver (Ag), or the like.

  Next, a vapor deposition apparatus for forming a thin film constituting a display element such as an organic EL element (that is, a thin film constituting at least one of the first electrode, the photoactive layer, and the second electrode) will be described. .

  FIG. 1 is a partially cut-away plan view schematically showing a vapor deposition apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II of the vapor deposition apparatus shown in FIG. FIG. 3 is a plan view schematically showing the structure of a vapor deposition boat provided in the vapor deposition apparatus shown in FIGS. 1 and 2. FIG. 4 is a cross-sectional view when the vapor deposition boat shown in FIG. 3 is cut along line IV-IV. FIG. 5 is a plan view schematically showing another structure of the evaporation boat provided in the evaporation apparatus shown in FIGS. 1 and 2. FIG. 6 is a cross-sectional view when the vapor deposition boat shown in FIG. 5 is cut along the line VI-VI. 1 to 6, the Z direction is a vertical direction, the X direction is a direction perpendicular to the Z direction, and the Y direction is a direction perpendicular to the X direction and the Z direction.

  As shown in FIGS. 1 and 2, the vapor deposition apparatus includes a vacuum chamber VC, a vapor deposition boat EB, a feeder WF, and a holder HLD. The vapor deposition apparatus also includes a power source PS, a drive mechanism (not shown), a controller (not shown), and the like.

  The vacuum chamber VC is connected to a vacuum exhaust system. The vacuum chamber VC is typically incorporated into a multi-chamber single wafer apparatus that sequentially forms thin films in a plurality of vacuum chambers. The vapor deposition boat EB, the feeder WF, and the holder HLD are disposed in the vacuum chamber VC.

  The vapor deposition boat EB is used to evaporate the vapor deposition material. The vapor deposition boat EB is disposed below the workpiece SUB on which the vapor deposition material is to be deposited. Typically, the vapor deposition boat EB is not disposed directly under the object to be processed SUB, but below the object to be processed SUB and at a position shifted in the X direction and / or Y direction from directly below the object to be processed SUB. Has been placed.

  The feeder WF feeds the wire EM made of a vapor deposition material and supplies it to the vapor deposition boat EB. In the present embodiment, the feeder WF accommodates a wire EM wound around a roll, and continuously or intermittently feeds the wire EM toward the vapor deposition boat EB. Further, in order to make the volume of the vacuum chamber VC as small as possible, the feeder WF is arranged so that the rotation axis of the roll is substantially parallel to the X direction. The vapor deposition material is, for example, a metal or an alloy. Here, the vapor deposition material is, for example, aluminum which is an electrode material of the organic EL element, and the diameter of the wire EM made of the vapor deposition material is 2 mm.

  The holder HLD detachably holds the workpiece SUB. In the present embodiment, the object to be processed SUB is a substrate, and the holder HLD is arranged so that the main surface of the object to be processed SUB (that is, the surface on which the vapor deposition material is deposited facing the vapor deposition boat EB) is substantially horizontal. That is, it is held so as to be substantially perpendicular to the Z direction.

  Further, a film thickness sensor (not shown) is disposed in the vacuum chamber VC. This film thickness sensor includes, for example, a structure in which electrodes are arranged on both sides of a quartz plate, and constitutes a quartz film thickness meter together with a controller. The film thickness sensor is disposed adjacent to the workpiece SUB in the X direction and / or the Y direction.

  The drive mechanism moves the holder HLD in a direction perpendicular to the Z direction with respect to the vapor deposition boat EB. In the present embodiment, the drive mechanism rotates the holder HLD so that the rotation axis thereof is parallel to the Z direction.

  The controller is connected to the drive mechanism, the film thickness sensor, the power source PS, and the feeder WF. The controller controls the operation of the drive mechanism. In addition, the controller controls the magnitude of the power output from the power source PS and the operation of the feeder WF based on the output from the film thickness sensor.

  As shown in FIGS. 3 and 4, the vapor deposition boat EB includes a resistance heating element HR and a pair of electrodes ED1 and ED2.

  The resistance heating element HR is formed of a non-metallic material, for example, ceramics including a conductive base material and an insulating layer covering the conductive base material. For example, carbon can be selected as the conductive base material. Further, the resistance heating element HR has a concave portion RS that is provided on the upper surface TS and to which a vapor deposition material is to be supplied.

  The resistance heating element HR has an elongated shape. In the present embodiment, the resistance heating element HR has a rectangular parallelepiped shape elongated in the Y direction. As an example, the dimension W1 in the X direction of the resistance heating element HR is 16 mm, and the dimension L1 in the Y direction is 100 mm. In addition, the recess RS is located substantially at the center of the resistance heating element HR and has a shape elongated in the Y direction. In the present embodiment, the recess RS has a forward tapered shape in which the opening diameter decreases from the upper surface TS of the resistance heating element HR toward the bottom surface BS of the recess RS. That is, the concave portion RS is configured by a wall portion WP that is inclined in all directions. As an example, the dimension W2 in the X direction of the opening of the recess RS is 9.6 mm, and the dimension L2 in the Y direction is 37.2 mm.

  The pair of electrodes ED1 and ED2 are arranged so as to sandwich the recess RS. In the present embodiment, the respective electrodes ED1 and ED2 are disposed at both ends of the resistance heating element HR on the upper surface TS of the resistance heating element HR. These electrodes ED1 and ED2 are made of, for example, a metal material. Note that an insulating layer is not formed on the portion of the resistance heating element HR that is in contact with the electrodes ED1 and ES2, and the electrodes ED1 and ED2 are in contact with the conductive base material.

  The electrodes ED1 and ED2 are connected to the power source PS. The resistance heating element HR generates heat when energized between the electrodes ED1 and ED2. The recess RS is provided on a conductive path that electrically connects the pair of electrodes ED1 and ED2. Further, the cross section perpendicular to the Y direction of the resistance heating element HR is small at the position of the recess RS. Therefore, when the resistance heating element HR is energized, the resistance heating element HR becomes high temperature. In particular, in the concave portion RS having a small cross-sectional area, the temperature becomes higher than that of the end portion of the resistance heating element HR. In this state, the vapor deposition material supplied to the recess RS is heated, melted, and evaporated to deposit the vapor deposition material on the workpiece SUB.

  The resistance heating element HR is formed of a nonmetallic material for the following reason. That is, when the vapor deposition material is a metal, when a metal resistance heating element HR is applied, the wettability of the melted vapor deposition material and the resistance heating element HR increases as the vapor deposition process continues, so that it exceeds the recess RS. It can happen that it extends outward and reaches the electrodes ED1 and ED2. In this case, since the electrical resistivity of the metal material is small, current flows through the spread deposition material. For this reason, the heating of the vapor deposition boat EB becomes insufficient, resulting in a problem that vapor deposition becomes impossible. Moreover, since the vapor deposition material that has reached the electrodes ED1 and ED2 is cured without melting, there is a problem that it is difficult to remove the vapor deposition boat EB. In order to solve such a problem, it is desirable to apply a vapor deposition boat EB made of a non-metal material having low wettability with respect to a metal material in order to suppress the spread of the vapor deposition material melted in the recess RS.

  The vapor deposition boat EB further includes a covering body CB disposed between the recess RS and at least one electrode on the upper surface TS of the resistance heating element HR. The cover CB is formed of a metal material and can be formed by a vapor deposition method or a CVD method. The arrangement direction of the recesses RS and the cover CB is parallel to the Y direction and parallel to the direction in which the elongated resistance heating element HR extends.

  The covering CB reduces the amount of radiant heat from the upper surface TS of the resistance heating element HR, and covers the resistance heating element HR exposed between the recess RS and the electrode. In particular, when the current is passed between the electrodes ED1 and ED2, the concave portion RS becomes high temperature. Therefore, it is desirable to dispose the covering body CB at least near the concave portion RS.

  In the example shown in FIGS. 3 and 4, the cover CB is disposed between the electrode ED1 and the recess RS. As an example, the dimension in the X direction of the cover CB is equal to the dimension W2, the dimension L3 in the Y direction is 8.1 mm, and the distance D between the cover CB and the recess RS is 4.2 mm.

  In the example shown in FIGS. 5 and 6, the covering CB1 is disposed between the electrode ED1 and the recess RS, and the covering CB2 is disposed between the electrode ED2 and the recess RS. The dimension examples of these coverings CB1 and CB2 may be the same as the examples shown in FIGS.

  According to the vapor deposition boat having such a configuration, the vapor deposition material supplied by the wire can be evaporated at a uniform rate. Moreover, according to the vapor deposition apparatus of such a structure, it becomes possible to form the thin film excellent in film thickness uniformity. This will be described with reference to FIGS. 3 and 4 and FIG.

  FIG. 8 is a plan view schematically showing a vapor deposition boat of the vapor deposition apparatus according to the comparative example.

  The vapor deposition apparatus which concerns on a comparative example has the structure similar to the vapor deposition apparatus of FIG.1 and FIG.2 except using the vapor deposition boat EB shown in FIG. Further, the vapor deposition boat EB shown in FIG. 8 has the same structure as the vapor deposition boat EB of FIGS. 3 and 4 except that the covering CB is omitted.

  The wire EM passes above the portion of the resistance heating element HR located between the one electrode ED1 and the recess RS until it reaches the recess RS after being fed out of the feeder WF. When the vapor deposition boat EB of FIG. 8 is used, since the covering CB is not provided, the wire EM is affected by the radiant heat from the upper surface TS of the resistance heating element HR before reaching the recess RS. In particular, when the resistance heating element HR formed of a non-metallic material is applied for the above-described reason, the heat radiation rate is higher than that of the metal material, so that the radiant heat received by the wire EM in the vicinity of the concave portion RS that becomes high is also large. Become. And the metal material which comprises the wire EM, ie, vapor deposition material, fuse | melts by receiving the radiant heat more than the melting | fusing point. As a result, a sphere having a diameter larger than the diameter of the wire EM may be formed at the tip of the wire EM.

  When the wire EM is sent to the recess RS in this state, more vapor deposition material is supplied to the recess RS than when the wire EM is sent to the recess RS without a sphere formed at the tip. Will be. As a result, the vapor deposition rate increases rapidly, and the vapor deposition material may bump into the recess RS. Then, due to such bumping, a convex portion may be formed on the thin film on the workpiece SUB. For this reason, when the vapor deposition boat EB of FIG. 8 is used, it is difficult to form a thin film with excellent film thickness uniformity.

  On the other hand, the vapor deposition boat EB of FIGS. 3 and 4 is formed on the upper surface TS of the resistance heating element HR with a metal material having a lower thermal emissivity than the nonmetallic material forming the resistance heating element HR. A covering CB is provided. For this reason, it becomes possible to reduce the radiant heat received although it is supplied toward the recessed part RS. Thereby, it can suppress that the front-end | tip of the wire EM melt | dissolves before reaching the recessed part RS, and it becomes difficult to form a spherical body at the front-end | tip of a wire. Therefore, a certain amount of vapor deposition material can always be supplied to the recess RS. Therefore, the probability of occurrence of bumping of the vapor deposition material can be reduced, and therefore a thin film having excellent film thickness uniformity can be formed.

  In this way, at least the upper surface TS of the resistance heating element HR facing the wire EM supplied toward the recess RS is covered with the covering CB (that is, from the electrode ED1 side in the example shown in FIGS. 3 and 4). By disposing the covering body CB at least between the electrode ED1 and the recess RS with respect to the supplied wire EM, it becomes possible to reduce the influence of the radiant heat from the resistance heating element HR on the wire EM.

  Further, as in the example shown in FIGS. 5 and 6, by disposing the coverings CB1 and CB2 between the pair of electrodes ED1 and ED2 and the recess RS, respectively, the electrode ED2 side as well as the electrode ED1 side is provided. It is also possible to supply the wire EM from. Thereby, it is possible to continuously supply the wire EM from the electrode ED2 side after the supply of the wire EM from the electrode ED1 side is completed. In addition, it is possible to prevent work mistakes when installing the vapor deposition boat EB in the vapor deposition apparatus.

  The effect mentioned above becomes so large that the distance D is short. That is, the vicinity of the recess RS becomes extremely high, and the wire EM supplied toward the recess RS is very close to the upper surface TS of the resistance heating element HR in the vicinity of the recess RS. For this reason, it is important to cover the upper surface TS close to the recess RS with the covering CB. According to the verification by the inventor, the distance D is preferably 6 mm or less, for example, and the distance D is preferably about 2 to 3 mm in consideration of the accuracy when forming the covering by vapor deposition or the like. preferable.

  However, when the distance D becomes zero, the vapor deposition material overflowing from the concave portion RS travels through the cover CB and spreads on the upper surface TS. For this reason, as for covering CB, it is desirable to arrange so that resistance heating element HR may be exposed between edge EG of crevice RS. That is, it is desirable that D> 0.

  Moreover, the effect mentioned above becomes so large that the dimension L3 is large. That is, it is desirable that the supplied wire EM pass over the covering CB. In particular, the upper surface TS that emits radiant heat equal to or higher than the melting point of the material constituting the wire EM is preferably covered with the covering CB, and according to the verification by the inventors, the dimension L3 is preferably 5 mm or more, for example. The dimension W2 is typically larger than the diameter of the wire EM.

  The above-described cover CB is formed of a metal material having a melting point higher than that of the vapor deposition material. When aluminum is selected as the vapor deposition material, a metal material having a melting point higher than that of aluminum, such as tungsten (W) or titanium (Ti), can be selected as the metal material for forming the cover CB.

  Naturally, tungsten has a lower thermal emissivity than a non-metallic material that forms the resistance heating element HR, such as carbon. That is, the thermal emissivity of carbon is 0.95, whereas the thermal emissivity of tungsten is 0.35. For this reason, the radiant heat which the wire EM receives is reduced to 37% compared with the case where the covering CB is not disposed.

  The surface of the cover CB is preferably a polished surface. That is, by polishing the surface of the cover CB, the reflectance is increased, and the action of reflecting mainly light rays such as infrared rays and far infrared rays is improved. That is, the absorption of light can be reduced, and as a result, the heat generation due to the light can be reduced, so that the thermal emissivity can be reduced as compared with the cover CB in which the metal material is simply formed. The thermal emissivity when tungsten is polished is 0.04 to 0.08. Thus, by applying the covering CB made of tungsten whose surface is polished, the radiant heat received by the wire EM is reduced to 8% as compared with the case where the covering CB is not disposed.

  In addition, this invention is not limited to the said embodiment itself, In the stage of implementation, it can change and implement a component within the range which does not deviate from the summary. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

FIG. 1 is a partially cutaway plan view schematically showing the configuration of a vapor deposition apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the vapor deposition apparatus shown in FIG. 1 cut along the line II-II. FIG. 3 is a plan view schematically showing the structure of a vapor deposition boat provided in the vapor deposition apparatus shown in FIGS. 1 and 2. FIG. 4 is a cross-sectional view of the vapor deposition boat shown in FIG. 3 cut along the line IV-IV. FIG. 5 is a plan view schematically showing another structure of the evaporation boat provided in the evaporation apparatus shown in FIGS. 1 and 2. FIG. 6 is a cross-sectional view of the vapor deposition boat shown in FIG. 5 cut along the line VI-VI. FIG. 7 is a cross-sectional view schematically showing the structure of an organic EL display element in which a part of the thin film is formed by the vapor deposition apparatus shown in FIG. FIG. 8 is a plan view schematically showing the structure of a vapor deposition boat applied to the vapor deposition apparatus according to the comparative example.

Explanation of symbols

  VC ... Vacuum chamber EB ... Vapor deposition boat WF ... Feeder HLD ... Holder PS ... Power source SUB ... Process target EM ... Wire TS ... Upper surface RS ... Recessed BS ... Bottom WP ... Wall CB ... Coating body HR ... Resistance heating element EG ... Edge ED ... electrode

Claims (6)

A vapor deposition boat used to evaporate vapor deposition material in a vapor deposition apparatus,
A resistance heating element formed of a non-metallic material and provided with a recess on the upper surface to which a vapor deposition material is to be supplied;
A pair of electrodes arranged to sandwich the recess of the resistance heating element;
A covering formed of a metal material and disposed between the recess and at least one electrode on the upper surface of the resistance heating element;
A vapor deposition boat characterized by comprising:   The vapor deposition boat according to claim 1, wherein the covering body is disposed so as to expose the resistance heating element between an edge of the concave portion.   The vapor deposition boat according to claim 1, wherein the covering is formed of a metal material having a melting point higher than that of the vapor deposition material.   The vapor deposition boat according to claim 1, wherein the surface of the covering is a polished surface.   The vapor deposition boat according to claim 1, wherein the resistance heating element has an elongated shape extending in an arrangement direction of the concave portion and the covering body. A vacuum chamber;
A vapor deposition boat disposed in the vacuum chamber for evaporating vapor deposition material;
A feeder for supplying a wire as a vapor deposition material to the vapor deposition boat;
A holder for holding an object to be deposited on the vapor deposition material evaporated from the vapor deposition boat in the vacuum chamber,
The vapor deposition boat is
A resistance heating element formed of a non-metallic material and provided with a recess on the upper surface to which a deposition material is to be supplied by the feeder;
A pair of electrodes arranged to sandwich the recess of the resistance heating element;
A covering body that is formed of a metal material and covers an upper surface of the resistance heating element that is between the recess and one of the electrodes and faces the wire supplied toward the recess;
A vapor deposition apparatus comprising:

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