JP2015074804A - Evaporation source, and vapor deposition apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oxidation and nitridation of metal materials that constitute a reflector and a crucible of an evaporation source, and to provide the reflector that keeps a high reflectance against infrared radiation of the evaporation source and the crucible that keeps a stable absorptivity of infrared radiation even after long time operation of the evaporation source.SOLUTION: An evaporation source includes: a crucible to store a deposition material; a nozzle connected with the crucible through which the vapor of the deposition material passes; a heater to heat the crucible; a plurality of side and back reflectors surrounding the crucible and the heater; and a plurality of front reflectors disposed around the nozzle. The side and back reflectors, the front reflectors, the crucible, and the nozzle each include a substrate and a film on a surface of the substrate. The film contains silicon, silicon oxide or silicon nitride or a complex compound thereof, or a compound of a metal element constituting the substrate and silicon.

Description

  The present invention relates to an evaporation source and a vapor deposition apparatus using the evaporation source.

  In recent years, organic devices have attracted attention as a new industrial field. For example, an organic EL has been developed as a display device and a lighting device, an organic transistor as a driving element such as organic EL, electronic paper, and RFID, and an organic thin film solar cell as a solar cell.

  In particular, organic EL is required to increase the size of the manufacturing substrate size along with the increase in size of the display device and lighting device, the substrate size from the current 4.5th generation manufacturing line (glass substrate dimensions: 730 mm × 920 mm), Expanded to 5.5th to 6th generation production lines (glass substrate dimensions are 1300 mm x 1500 mm to 1500 mm x 1800 mm), which is more than 2.9 times the substrate dimensions, and further to the 8th generation production line (glass substrate dimensions: 2200 mm) × 2500 mm). Also, production of organic thin-film solar cells using roll-to-roll (R2R) is beginning. In the production of these organic devices, vapor deposition apparatuses for organic materials and metal materials are mainly used, and the size of the vapor deposition apparatus is increasing.

  Along with the increase in the size of the vapor deposition apparatus, the size of the evaporation source used therein is also increasing. For example, a large linear evaporation source or a surface evaporation source has been used for vapor deposition of organic materials. In addition, as a metal evaporation source for electrode materials such as magnesium, silver, and aluminum, a plurality of point evaporation sources including a large linear evaporation source and a large crucible have been used.

  As a new problem accompanying the increase in the size of the evaporation source, there is an increase in heat radiation from the evaporation source. When thermal radiation increases, for example, a metal mask used for patterning of an organic material during organic vapor deposition thermally expands due to thermal radiation, resulting in a problem that patterning position accuracy decreases. Moreover, since metal deposition at the time of electrode formation has a higher deposition temperature than organic deposition, there is a problem that the organic film itself on the substrate is thermally deteriorated due to high-temperature heat radiation. In addition, the power consumption of the evaporation source becomes too large, leading to an increase in apparatus costs such as a power source and an increase in running costs such as electricity bills.

  Therefore, a heating unit such as a crucible of the evaporation source is designed to be confined in the evaporation source by a reflector that reflects infrared rays of heat radiation, except for a nozzle unit through which the evaporation material passes. As a reflector that reflects infrared rays, a stainless steel plate (hereinafter also referred to as a “stainless steel plate”) such as a stainless steel plate (hereinafter also referred to as a “stainless steel plate”) for organic deposition at a relatively low temperature of about 250 to 400 ° C. is high. A metal plate such as a melting point metal molybdenum plate is often used.

  Patent Document 1 discloses an infrared reflector that reflects infrared rays generated by an evaporation source and includes at least a multilayer structure formed in the order of an Au film or a Pt film, a dielectric film, and a base material from the heated object side. Yes.

JP 2008-227001 A

  In the case of the infrared reflector described in Patent Document 1, since an inactive Au (gold) film or the like is used, there is generally a problem that the adhesion of the reflector to the base material is very low, and that it is easy to diffuse into the base material. It is. Therefore, a complicated coating technique such as a multilayer film in which a thin Au film is sandwiched between dielectric films as described in Patent Document 1 is required.

  An object of the present invention is to provide a reflector that prevents oxidation and nitridation of a metal material that constitutes a reflector of an evaporation source, and maintains a high reflectance with respect to the radiation infrared rays of the evaporation source even if the evaporation source is operated for a long time. Another object of the present invention is to realize an evaporation source and an evaporation apparatus that can stably deposit for a long period of time.

  Another object of the present invention is to provide a crucible that prevents the progress of oxidation and nitridation of a heating part such as a crucible or nozzle of an evaporation source and maintains a constant emissivity even when the evaporation source is operated for a long time. It is to realize an evaporation source and an evaporation apparatus that can stably deposit for a long period of time.

  The present invention relates to a crucible for storing a vapor deposition material, a nozzle connected to the crucible through which vapor of the vapor deposition material passes, a heater for heating the crucible, a plurality of side and back reflectors surrounding the crucible and the heater, and a nozzle In the evaporation source including a plurality of front surface reflectors disposed around the side surface / back surface reflector and the front surface reflector include a base material and a coating provided on the surface of the base material. It is characterized by containing a compound of silicon alone, silicon oxide or silicon nitride, or a metal element constituting the substrate and silicon.

  The present invention also provides a crucible for storing a vapor deposition material, a nozzle connected to the crucible through which vapor of the vapor deposition material passes, a heater for heating the crucible, and a plurality of side and back surface reflectors surrounding the crucible and the heater, In the evaporation source including a plurality of front surface reflectors arranged around the nozzle, the crucible and the nozzle include a base material and a film provided on the surface of the base material. It contains silicon or silicon nitride, or a compound of a metal element constituting a base material and silicon.

  ADVANTAGE OF THE INVENTION According to this invention, the evaporation source and vapor deposition apparatus which can be vapor-deposited stably for a long period of time are realizable.

It is a schematic cross section which shows the structure of a typical linear evaporation source. It is a graph which shows the wavelength dependence of the spectral diffuse reflectance before and after long-term use of the conventional stainless steel base material. It is a graph which shows the wavelength dependence of the spectral diffuse reflectance before and after long-term use of the conventional molybdenum base material. It is sectional drawing which shows the structure of the reflector which provided the film on both surfaces of the base material. It is sectional drawing which shows the structure of the reflector which provided the film on the single side | surface of a base material. It is a graph which shows the wavelength dependence (measurement result) of the specular regular reflection factor of the reflector which sputtered the film which consists of silicon on the base material of a stainless steel plate, and the radiance (approximate with black body radiation) of 300 ° C thermal radiation. . It is a graph which compares and shows the result of having calculated | required the spectral reflectance by the optical interference of the Si thin film on a metal substrate, and the radiance (approximate with black body radiation) of 250 degreeC and 400 degreeC thermal radiation. Changes in spectroscopic reflectance on the short wavelength side (measurement results) and radiance of thermal radiation at 300 ° C. when a reflector made by forming a silicon film on a stainless steel substrate is baked in an air atmosphere (measurement result) It is a graph which shows (approximated by black body radiation). Changes in spectral diffuse reflectance (measurement results) when a reflector produced by forming a silicon film on a stainless steel substrate is baked in an air atmosphere, and radiance of thermal radiation at 250 ° C. and 400 ° C. ( It is a graph showing a comparison with (approximate black body radiation). A graph showing the results of measuring the specular reflectance of a reflector made by sputtering a silicon film on a molybdenum substrate, and the radiance of 1000 ° C. thermal radiation (approximate black body radiation). is there. It is a graph which compares and shows the result of having calculated | required the spectral reflectance by the optical interference of the Si thin film on a metal substrate, and the radiance (approximate with black body radiation) of 1000 degreeC thermal radiation. When the reflector produced by forming a silicon film on a molybdenum substrate is baked in a nitrogen atmosphere at 1000 ° C., the spectroscopic reflectance measurement results before and after the baking, and the radiance of the heat radiation at 1000 ° C. (black) It is a graph which shows (approximate by body radiation). Changes in spectral diffuse reflectance when a reflector made by forming a silicon film on a molybdenum substrate is baked in a nitrogen atmosphere, and the radiance of thermal radiation at 1000 ° C. (approximate with black body radiation) It is a graph to show. It is sectional drawing which shows the detailed structure of the film which passed through the state of high temperature. It is a top view which shows the example of the cluster type vapor deposition apparatus for organic EL manufacture provided with the organic linear evaporation source and metal evaporation source of this invention. It is a schematic diagram which shows an example of the organic vapor deposition chamber which comprises an organic cluster. It is sectional drawing which shows the structure of an organic linear evaporation source. It is a schematic diagram which shows an example of the metal vapor deposition chamber which comprises a metal cluster.

  The features of the present invention are as follows.

  1. On the reflector that reflects the radiant infrared of the evaporation source, or on the metal substrate that constitutes the crucible and nozzle that absorbs the radiant infrared, a surface that prevents oxidation and nitridation of the substrate and has high transmittance in the radiant infrared wavelength region Apply coating.

  2. The film (film) formed by the above surface coating has a diffusion rate of oxygen or nitrogen smaller than the diffusion rate of oxygen and nitrogen in the reflector substrate.

  3. The surface coating film has a higher free energy of formation of oxide or nitride than the free energy of formation of oxide or nitride of the reflector substrate.

  4). The surface coating film has an oxide film or nitride film whose evaporation source has a higher transmittance with respect to radiant infrared rays than the oxide film or nitride film of the reflector substrate.

  5. Silicon is mainly used as the material for the surface coating film.

  6). In the surface coating film, the surface layer may be an oxide or nitride of silicon or a composite compound thereof, and the interface layer with the base material of the reflector may be a silicide of a material constituting the base material. Here, the composite compound refers to a substance formed by chemical bonding of silicon (silicon), oxygen, nitrogen or the like.

  7). The film thickness of the surface coating film (there may be a surface layer and an interface layer) is 25 nm or more and 200 nm or less (25 to 200 nm).

  8). Between the surface coating film and the base material of the reflector, a metal film having a higher reflectance of radiant infrared rays than the reflector base material is inserted.

  9. Between the surface coating film and the base material of the crucible or nozzle, a film having a radiation infrared radiation rate (= absorption rate) higher than that of the base material is inserted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions. Various modifications by those skilled in the art are within the scope of the technical idea disclosed in this specification. Changes and modifications are possible. In all the drawings for explaining the present invention, components having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

  FIG. 1 shows a cross-sectional structure of a typical linear evaporation source.

  In this figure, the linear evaporation source includes a crucible 1 for storing a vapor deposition material (melt 6), a nozzle 2 connected to the crucible 1 and through which the vapor deposition material (vapor) passes, a heater 3 for heating the crucible 1, a crucible 1 and a heater. 3 includes a plurality of side surface / back surface reflectors 4 surrounding the substrate 3 and a plurality of front surface reflectors 5 arranged around the nozzle 2 to suppress thermal radiation to a substrate (not shown) to be deposited. Has been. Depending on conditions, a jacket (not shown) for water-cooling around the side / back surface reflector 4 may be provided. The side / back surface reflector 4 and the front surface reflector 5 have a base material made of a metal plate. In this description, the side surface / back surface reflector 4 is integrated, but the side surface reflector and the back surface reflector may be separated and combined.

  The metal plates of the side / back surface reflector 4 and the front surface reflector 5 are generally finished in a mirror shape having a metallic luster in order to increase the reflectance of infrared rays. As a result, it is possible to efficiently confine infrared rays in the evaporation source, reduce heat radiation from the evaporation source to the substrate, increase the heating efficiency of the crucible 1, and reduce the power consumption of the heater 3. On the other hand, the crucible 1 and the nozzle 2 are preferably blackened on the surface to increase the radiation rate (= absorption rate) in order to efficiently absorb the infrared rays emitted by the heater and the infrared rays reflected by the reflector.

  However, the metal plates of the side surface / back surface reflector 4 and the front surface reflector 5 are gradually discolored (blackened) as the evaporation source is used for a long time, and the infrared reflectance decreases. This is because the evaporation source is used at a high temperature, so that it reacts with a slight amount of oxygen remaining in the chamber to form an oxide film, or the evaporation source is cooled when the evaporation material is replaced. This is because a nitride film is formed on the surface by introducing nitrogen into the chamber while the temperature is still high. On the other hand, the crucible 1 and the nozzle 2 are often either a metal substrate as it is or the surface is previously blackened by oxidation or nitridation. However, since the evaporation source is used at a high temperature, the emissivity fluctuates because the oxide film or the nitride film is formed thicker. On the other hand, in the case of metals that form highly volatile oxides such as molybdenum, on the contrary, when used at high temperatures in a vacuum, the oxide film scatters and the metal surface has a low emissivity (= high reflectivity). It may be exposed and the thermal efficiency of the crucible 1 or the nozzle 2 may deteriorate.

  In the present specification, the side surface / back surface reflector 4 and the front surface reflector 5 are collectively referred to as a “reflector”.

  Fig. 2A shows the spectral radiance before and after long-term use of stainless steel used for reflectors, crucibles, and nozzles of organic evaporation sources, and the spectral radiance of thermal radiation (approximate black body radiation) at the evaporation source heating temperature (300 ° C). Is shown.

  As shown in the figure, the radiance at 300 ° C. (one-dot chain line) becomes a maximum near a wavelength of 5 μm. The stainless steel before use has a wavelength of 3 μm or more and a reflectance of 65% or more (solid line). On the other hand, the reflectance of stainless steel after use decreases particularly at a wavelength of 10 μm or less, and is about 40% at a wavelength of 5 μm (dashed line). Stainless steel is considered to be because a surface oxide film is formed by long-term use.

  FIG. 2B shows the spectral reflectance before and after the long-term use of molybdenum used in a reflector or crucible of a metal evaporation source, and the spectral radiance of thermal radiation (approximate black body radiation) at the evaporation source heating temperature (1000 ° C.). It is a thing.

  As shown in the figure, the radiance at 1000 ° C. (the one-dot chain line) becomes a maximum near a wavelength of 3 μm. Molybdenum before use has a wavelength of 3 μm or more and a reflectance of 80% or more (solid line). On the other hand, the reflectance of molybdenum after use particularly decreases at a wavelength of 10 μm or less, and is about 50% at a wavelength of 5 μm (broken line). Molybdenum is considered to be because a surface nitride film is formed by repeated nitrogen leaks.

  From FIGS. 2A and 2B, the wavelength range where the reflectance decreases and the wavelength range where the thermal radiation radiance is strong at the use temperature of the evaporation source coincide with each other. It can be seen that the infrared reflection performance is greatly reduced. On the other hand, crucibles and nozzles using stainless steel or molybdenum increase the amount of infrared absorption due to oxidation or nitridation, which can be a cause of temperature fluctuation.

  2A and 2B, the total reflectance in the measured entire wavelength region (1.6 to 25 μm) (the value obtained by dividing the integrated amount of reflection in the measured wavelength region by the integrated amount of radiation) is calculated at 300 ° C. The total reflectance of the heat radiation of the stainless steel used is 80.8% before use, but decreases to 59.4% after long-term use. Moreover, the total reflectance of the heat radiation of molybdenum used at 1000 ° C. is 87.3% before use, but decreases to 47.3% after long-term use. Therefore, heat loss at the evaporation source reflector increases at the same heater output. On the other hand, the heat absorption of crucibles and nozzles increases. When the loss exceeds, the evaporation source temperature decreases, so the deposition rate gradually decreases. When the heater output is feedback-controlled at a constant rate, the power consumption of the heater 3 gradually increases. When the absorption exceeds, the evaporation source temperature rises, and the deposition rate gradually increases.

  In addition, the total reflectance of the heat radiation by the stainless steel used at 400 ° C. is 75.9% before use, but decreases to 54.8% after long-term use.

  The decrease in the reflectance of the front reflector 5 causes an increase in heat radiation to the substrate on which the film is formed. That is, since the radiation rate has a relationship of (radiation rate) = 1− (reflectance) according to Kirchhoff's law, the front-surface reflector 5 having a reduced reflectivity, that is, the front-surface reflector 5 having an increased radiation rate, Become. The periphery of the nozzle portion through which the evaporation material of the evaporation source passes is surrounded by the front surface reflector 5 for confining heat radiation. However, since the emissivity of the front surface reflector 5 increases, the heat to the opposing substrate is increased. Radiation will increase. As a result, the temperature of the metal mask in contact with the substrate gradually rises, causing problems such as a decrease in positional accuracy due to thermal expansion and deterioration of the organic film on the substrate.

<Embodiment of the reflector of the evaporation source>
A metal plate is used for the base material 10 of the side surface / back surface reflector 4 and the front surface reflector 5 shown in FIG. Various materials can be used as the material of the base material 10, but those used for heating at a relatively low temperature (about 250 to 400 ° C.) such as an organic evaporation source have a relatively high temperature such as a metal evaporation source such as a stainless steel plate (400 A high melting point metal plate such as a molybdenum plate is used for heating to about 1000 ° C.). The plate thickness can be set variously, but a metal plate of about 0.1 to 0.3 mm is often used. These metal plates are preferably mirror-finished so as to have a metallic luster and are kept as high as possible in reflectance.

  FIG. 3 shows a cross-sectional structure of the reflector of the present invention.

  In this figure, the reflector has a film 11 (surface coating film) on both surfaces of the substrate 10. The coating 11 is formed by a sputtering method using silicon (silicon alone).

  FIG. 4 shows another example of the reflector of the present invention.

  In this figure, the reflector has a coating 11 on one side of the substrate 10.

  As the base material 10, a metal plate such as a stainless steel plate or a molybdenum plate is used. The material of these base materials 10 is an exemplification, and is composed of any element as long as it is a metal plate (including an alloy plate) that is heat resistant in the use temperature range (the melting point is sufficiently higher than the use temperature range). Also good.

  The coating 11 is preferably performed on both sides of the base material 10 as shown in FIG. 3, but it may be provided on only one side as shown in FIG. In the case of providing the coating 11 on only one side, the surface on which the coating 11 is provided is used toward the heating portion of the evaporation source. 3 and 4 show the case where the thickness of the coating 11 is 80 nm, but the thickness is not limited to this, and is preferably about 25 to 200 nm.

  The reason why the coating 11 is formed of silicon having a thickness of about 25 to 200 nm is as follows.

  1. Silicon is a semiconductor having a band gap of about 1.1 eV, has little absorption in the infrared region with a wavelength of about 1.4 μm or more (extinction coefficient ˜0), and is almost transparent to infrared rays with longer wavelengths. . That is, if silicon is used, the transmittance of the radiation infrared spectrum (approximated by blackbody radiation, peak wavelength is about 2.5 to 5 μm) generated in the temperature range (250 ° C. to 1000 ° C.) where the evaporation source operates. A high film 11 can be formed.

  2. Silicon forms a dense oxide film or nitride film in an oxidizing atmosphere and a nitriding atmosphere, and the rate of oxidation or nitridation decreases according to the parabolic law with respect to time. For this reason, the diffusion rate of oxidizing species and nitriding species is very slow. Silicon has a larger change in free energy of formation of oxides and nitrides than metals such as Fe, Cr and Mo, and silicon has a high ability to getter oxygen and nitrogen. Therefore, by using the silicon coating 11, oxidation and nitridation of the base material 10 of the side / back surface reflector 4 (front surface reflector 5) can be prevented. Further, since the rates of oxidation and nitridation are slow, the minimum required film thickness of the film 11 may be thin, and 25 nm or more is sufficient.

  3. Silicon oxide films and nitride films are wide-gap insulators and are almost transparent over a wide wavelength range from visible light to infrared light. Therefore, even if the surface of the silicon film 11 is oxidized or nitrided, the film 11 having a high transmittance with respect to the spectrum of radiant infrared rays can be maintained.

  4). When heated, the silicon causes a silicide reaction with the metal plate of the substrate 10 to form an interface layer of silicide. This silicide layer improves the adhesion between the silicon (film 11) and the substrate 10, and forms the film 11 that is difficult to peel off from the substrate 10. Further, the speed of oxidation and nitridation of silicide is not much different from that of silicon, and is effective in preventing the diffusion of oxidizing species and nitriding species into the substrate 10.

  5. By setting the thickness of the coating 11 to 25 to 200 nm, the reflectance in the thermal radiation spectrum region of the evaporation source caused by optical interference in the coating 11 is avoided, and the temperature range (250 ° C. to 1000 ° C.) at which the evaporation source operates. ), The coating film 11 having a high transmittance can be formed.

  FIG. 5 shows the spectral specular reflectance of a reflector obtained by sputtering a silicon (Si) coating on a mirror-finished stainless steel plate (SUS steel) at a wavelength of 400 nm to 2500 nm in a short wavelength range where optical interference easily occurs. The results are shown.

  In this figure, the case where the thickness of the film is 49 nm, 67 nm, and 109 nm (in the figure, for example, “Si 49 nm / SUS” is described when the thickness is 49 nm) is shown. For comparison, a mirror-finished stainless steel plate (noted as “SUS” in the figure) without a coating is also shown. Further, the radiance at 300 ° C. is indicated by a broken line.

  In the case of a stainless steel plate (SUS) that has only been mirror-finished, the reflectance increases monotonously as the wavelength increases. On the other hand, in the case of a stainless steel plate on which a silicon film is formed, the reflectance vibrates particularly in the short wavelength side in the region from visible light to near infrared rays due to optical interference in the silicon film. The wavelength of the low reflection peak at which the reflectivity is the lowest due to the influence of optical interference in the silicon film (the wavelength at which the reflectivity is minimized) is about 1200 nm (1.2 μm) when the film thickness is 49 nm, and the film thickness is 67 nm. In this case, the wavelength is about 1900 nm (1.9 μm), and when the film thickness is 109 nm, the wavelength is about 2500 nm (2.5 μm).

  On the other hand, for example, the bottom of the short wavelength side of the thermal radiation infrared ray at 300 ° C. is about 1400 nm (1.4 μm), and the reflectance can be most enhanced when the film thickness of silicon is 49 nm.

  FIG. 6 is a graph showing the results obtained by simulating the spectral reflectance due to optical interference of the Si thin film on the metal substrate and the radiance of thermal radiation at 250 ° C. and 400 ° C. In the figure, the reflectance is indicated by a solid line, and the radiance is indicated by a broken line. The display in nanometers is the film thickness. The Si film is assumed to be a single-layer film having a refractive index of 3.5, and the reflective characteristics are slightly different from the actual Si film due to the presence or absence of surface oxidation, but the general tendency is the same.

  From this figure, it can be seen that as the film thickness of Si increases, the value of the wavelength at which the reflectance is minimized tends to increase. When the film thickness is 200 nm, the wavelength at which the reflectance is minimized is 2100 nm. On the other hand, the radiance of thermal radiation at 250 ° C. and 400 ° C. is negligibly small at wavelengths of 2000 nm or less.

  Therefore, if the film thickness of Si is set to 200 nm or less, the wavelength of the low reflection peak at which the reflectivity is the lowest due to the influence of optical interference is set to a shorter wavelength side than the radiance tail of heat radiation at 250 to 400 ° C. Can do. Therefore, a preferable Si film thickness is 25 to 200 nm.

  FIG. 7 shows that when a reflector having a 49 nm-thick silicon film formed on a stainless steel substrate is heated and baked in an air atmosphere at 600 ° C. for 2 hours, the specular specular reflectance before and after baking is from 400 nm to 400 nm. Measured at 2500 nm and compared.

  The calcination treatment at 600 ° C. was an oxidative condition that was considerably more severe than the conditions for using an organic evaporation source (in vacuum, 250 to 400 ° C.), and was performed as an accelerated test.

  From this figure, it can be seen that the change in the specular regular reflectance of the reflector is small and that oxidation can be prevented. Moreover, the high reflectance close | similar only to a stainless steel plate (SUS steel) has been acquired especially in the long wavelength side where the thermal radiation spectrum from a crucible increases.

  FIG. 8 shows a case where a reflector having a 49 nm-thickness silicon film formed on a stainless steel substrate is heated and baked in an air atmosphere at 600 ° C. for 2 hours, and the spectral diffuse reflectance before and after baking is 1.6 μm in wavelength. Comparison is made at ˜25 μm. In the figure, the radiance at 250 ° C. and 400 ° C. is indicated by broken lines.

  The diffuse reflectance is measured using an integrating sphere. Compared with a reflector made only of a stainless steel plate, a reflector in which a silicon film having a film thickness of 49 nm is formed on a stainless steel plate substrate has a slightly lower reflectance on the short wavelength side, but it is 2 in an air atmosphere at 600 ° C. The reflectance hardly changes before and after the time heating and baking.

  When the total reflectance in the measured whole wavelength region (1.6 to 25 μm) shown in this figure is calculated, the total reflectance with respect to thermal radiation at 400 ° C. of the reflector of the stainless steel plate is 75.9%. On the other hand, the total reflectance before firing of the reflector formed by forming a 49 nm-thick silicon film on a stainless steel substrate is 72.5%, and the total reflection after heating and firing in an air atmosphere at 600 ° C. for 2 hours. The rate is 71.4%, and the decrease in reflectance is very slight.

  FIG. 9 shows the results of measuring the specular reflectance of a reflector obtained by sputtering a coating made of silicon on a mirror-finished molybdenum plate (Mo) substrate. In the figure, the reflectance is indicated by a solid line, and the radiance (1000 ° C.) is indicated by a broken line. The display in nanometers is the silicon film thickness. The range of the film thickness is 49 nm to 109 nm. The wavelength range is 400 nm to 2500 nm. The results of specular reflectance of a molybdenum plate that has been mirror-finished are also shown.

  In this figure, the molybdenum plate that has only been mirror-finished exhibits the characteristic that the reflectance increases monotonously as the wavelength increases. On the other hand, a reflector in which a silicon film is sputtered onto a molybdenum plate base material vibrates at a short wavelength side from the visible light to the near-infrared region due to optical interference in the silicon film. The wavelength of the low reflection peak at which the reflectance is most lowered due to the influence of optical interference in the silicon thin film is about 1300 nm (1.3 μm) when the film thickness is 49 nm, and about 1900 nm (1. 9 μm) and a film thickness of 109 nm, the wavelength is about 2200 nm (2.2 μm). The peak of the thermal radiation spectrum (approximated by blackbody radiation) from an evaporation source heated to 1000 ° C. is about 2200 nm (2.2 μm) according to the Wien's displacement law, and the tail on the high wavelength side of the thermal radiation spectrum is about It becomes 900 nm (0.9 μm). Therefore, it is possible to reflect heat radiation more efficiently by using a thin film.

  FIG. 10 shows the result of comparison of the spectral reflectance due to optical interference of the Si thin film on the Si film metal substrate by simulation and the radiance of thermal radiation at 1000 ° C. In the simulation, the Si film is assumed to be a single layer film with a refractive index of 3.5, and the reflection characteristics are slightly different from the actual Si film due to the presence or absence of surface oxidation, etc. It is the same.

  According to this simulation, when the Si film thickness is about 70 nm or less, the wavelength of the low reflection peak at which the reflectance decreases most due to the influence of optical interference is set to a shorter wavelength side than the bottom of the radiance of 1000 ° C. thermal radiation. can do. Therefore, considering the oxidation and nitridation rates of the Si film, the preferable Si film thickness is 25 to 70 nm.

  FIG. 11 shows the spectral regular reflectance before and after firing for 400 hours when a reflector plate in which a silicon film with a film thickness of 49 nm is formed on a base material of molybdenum plate is heated and fired in a nitrogen atmosphere at 1000 ° C. for 2 hours. Comparison is made at 2500 nm.

  The firing process (1000 ° C.) simulates a state in which a high-temperature evaporation source is rapidly cooled due to a nitrogen leak in a vacuum chamber during material exchange, and is an accelerated test at a temperature higher than the actual temperature.

  As can be seen from this figure, the specular reflectance of the reflector plate fired and fired in a nitrogen atmosphere at 1000 ° C. for 2 hours is improved in the reflectance on the short wavelength side as compared with that before firing. This is because the silicon nitridation proceeds at a high temperature of 1000 ° C., and a relatively large amount of silicon nitride is formed, so that the refractive index is lower than that of silicon (the refractive index is intermediate between silicon 3.5 and silicon nitride 1.9) This is because optical interference is suppressed. Further, the high reflectivity is obtained because nitridation of molybdenum of the base material does not occur, and the diffusion of nitrogen is sufficiently suppressed.

  FIG. 12 shows a mirror-finished base material of molybdenum plate, a reflector plate obtained by sputtering a 49 nm-thickness silicon film on the base material, and this reflector plate heated and fired in a nitrogen atmosphere at 1000 ° C. for 2 hours. The spectral diffuse reflectance of the product was measured at wavelengths of 1.6 μm to 25 μm and compared.

  Compared to the base material of the molybdenum plate, the reflector formed with a 49 nm thick silicon film on the base material of the molybdenum plate has a slightly lower reflectivity on the short wavelength side, but the reflectivity is almost the same before and after firing. It has not changed. When the total reflectance in the measured whole wavelength region (1.6 to 25 μm) shown in this figure is calculated, it is 87.3% of the total reflectance with respect to 1000 ° C. thermal radiation of the base material of the molybdenum plate. On the other hand, the total reflectance before firing of the reflector in which the silicon film having a film thickness of 49 nm is formed on the substrate of the molybdenum plate is 83.3%, and the total reflection after heating and firing in a nitrogen atmosphere at 1000 ° C. for 2 hours. The rate is 83.7%, and the decrease in reflectivity is very slight.

  From the above results, it can be seen that the structure of the film used in the evaporation source and subjected to the high temperature state changes from the initial state of the film formation.

  Table 1 summarizes the effects of the silicon coating.

  In this table, after use (after heating), the reflector based on SUS steel was fired and fired at 600 ° C. for 2 hours in an air atmosphere, and the reflector based on molybdenum was in a nitrogen atmosphere. Heat-fired at 1000 ° C. for 2 hours.

  From this table, it can be seen that the reflectance of both SUS steel and molybdenum decreases by 20% or more by heating. On the other hand, when a silicon film is provided, the reflectance is almost the same before and after heating.

  FIG. 13 shows a more detailed structure of the coating that has undergone a high temperature state.

  As shown in this figure, the silicon film (coating 11) formed on the substrate 10 is oxidized by a maintenance in the atmosphere or a reaction with residual oxygen when heated in a vacuum chamber, or a high temperature. In this state, nitrogen is leaked and nitrided. Therefore, a surface layer 12 of an oxide or nitride of Si or a composite compound thereof is formed outside the coating 11. On the other hand, the interface layer 13 on the base material 10 side is a silicide layer formed by the reaction of the metal of the base material 10 and silicon when used at a high temperature. An intermediate layer 14 made of remaining silicon is formed between the surface layer 12 and the interface layer 13. As described above, the coating 11 is naturally formed with a structure of approximately three layers.

  In the above example, a stainless steel plate or a molybdenum plate is used as the reflector base material, but other metal plates may be used as long as the above conditions are satisfied. For example, tantalum, tungsten, niobium, titanium, nickel, chromium, and alloys thereof can be used.

  In addition, it is possible to further increase the reflectivity of the reflector by providing a metal thin film having a higher infrared reflectivity than the base metal such as copper between the metal plate of the base material of the reflector and the silicon film.

<Embodiment of crucible and nozzle of evaporation source>
A metal plate is used for the base material 10 of the crucible 1 and the nozzle 2 shown in FIG. Various materials can be used as the material of the substrate 10, but those used for heating at a relatively low temperature (about 250 to 400 ° C.) such as an organic evaporation source have a relatively high temperature such as a metal evaporation source such as stainless steel and titanium ( A high melting point metal such as molybdenum is used for the one heated to about 400 to 1000 ° C. Although the plate thickness can be set variously, a metal having a plate thickness of about 10 to 20 mm is often used. In some cases, not only plate materials but also metal blocks are cut out. These metals can be used as they are, but in order to absorb infrared rays efficiently, it is preferable to increase the radiation rate (= absorption rate) by blackening the surface. Specifically, it is effective to blacken the surface by oxidizing or nitriding the surface like stainless steel or molybdenum in FIGS. 2A and 2B.

  In the crucible 1 and the nozzle 2, the film 11 (surface coating film) is formed on the blackened stainless steel or molybdenum as in the first embodiment. The coating 11 is formed by a sputtering method using silicon (silicon alone). As described in Example 1, this film causes optical interference in the short wavelength range, but is almost transparent in the wavelength range of the radiant infrared, and the emissivity of the blackened stainless steel or molybdenum, for example, in FIGS. 2A and 2B. The emissivity shown can be substantially maintained.

  When calculating based on FIG. 2A and FIG. 2B, the relationship of total absorptivity = total emissivity = 1−total reflectivity is established, so that the emissivity of crucibles and nozzles when using stainless steel at 300 ° C. (= absorptivity) ) Is improved from 19.2% (100-80.8%) in the case of stainless steel as it is to 40.6% (100-59.4%) by blackening treatment. The emissivity (= absorption rate) of the crucible or nozzle when using molybdenum at 1000 ° C. is from 12.7% (100 to 87.3%) in the case of the molybdenum metal as it is, by performing blackening treatment. Improve to 7% (100-47.3%). That is, the crucible 1 and the nozzle 2 having a high absorption rate and high thermal efficiency can be obtained, and the power consumption of the evaporation source can be reduced. In addition, this coating prevents oxidation and nitridation of the underlying blackened film by the same oxidation and nitridation prevention effects as in Example 1, and suppresses fluctuations in emissivity. Can be obtained.

  In addition, a cermet film (an oxide film or a nitride film in which metal nanoparticles are dispersed), such as a cermet film, between the metal plate and the silicon film of the base material of the crucible 1 or the nozzle 2 is more infrared than a blackened film by oxidation or nitridation of the base material By providing a thin film having a higher emissivity (= absorption rate), the emissivity of the crucible or nozzle can be further increased.

  Moreover, although the present Example showed the example which performed the blackening process etc. to the crucible and the nozzle, even if it coat | covers directly on the metal base material which does not perform a blackening process etc., a radiation rate fluctuation | variation is carried out similarly to Example 1. It is possible to obtain a stable evaporation source with little change over time.

<Embodiment of vapor deposition apparatus>
FIG. 14 shows an example of a cluster type vapor deposition apparatus for producing an organic EL provided with an organic linear evaporation source and a metal evaporation source according to the present invention.

  The organic EL manufacturing apparatus generally has a configuration in which an organic cluster 20 for forming various organic layers and a metal cluster 40 are connected. The organic cluster 20 is centered on a cassette 21 and a load chamber 22, and a robot chamber 24 connected to the load chamber 22 via a substrate relay chamber 23, and a hole injection layer deposition chamber 25 and a hole transport are provided on both sides of the robot chamber 24. A configuration in which a layer deposition chamber 26, a red light emitting layer deposition chamber 27, a green light emitting layer deposition chamber 28, a blue light emitting deposition chamber 29, a hole blocking layer deposition chamber 30, an electron transport layer deposition chamber 31, and an electron injection layer deposition chamber 32 are arranged. It is said.

  Each chamber is partitioned by a gate valve 33, and the substrate is transferred by the transfer robot 34. In each organic vapor deposition chamber, there are two substrate transfer portions 35, and an organic linear evaporation source 36 capable of scanning left and right and up and down allows one to perform alignment of the mask while the other is during deposition, The tact can be doubled.

  The substrate formed up to the electron transport layer on the TFT substrate in the organic cluster 20 is sent to the substrate relay chamber 23, and Mg in the metal deposition chamber 41 of the metal cluster 40 using the metal linear evaporation source 42 and the metal point evaporation source 43. -Ag alloy etc. are formed into a film. Thereafter, the substrate is transferred from the substrate relay chamber 23 to the unload chamber 44 and transferred to the sealing step.

  FIG. 15 schematically shows an example of an organic vapor deposition chamber (also referred to as a “deposition chamber”) constituting the organic cluster 20 of FIG.

  This figure shows an example of a side deposition method in which a film is formed with the substrate 51 standing substantially vertically.

  In general, the organic vapor deposition chamber 50 includes a gate valve 33, a substrate transfer unit 35, a substrate for maintaining a vacuum with a processing vacuum chamber 52 (also simply referred to as “vacuum chamber”) and a robot chamber (not shown). A drive unit 53 for standing 51 substantially vertically, a metal mask 54, an organic linear evaporation source 36 disposed in the horizontal direction, and the like are included. The organic linear evaporation source 36 is a scanning method in which the organic linear evaporation source 36 is arranged in series longer than the horizontal side of the substrate 51 and forms a film on the entire surface of the substrate 51 by scanning in the height direction of the substrate 51. In some cases, the organic linear evaporation source 36 may be combined in multiple stages so as to perform co-evaporation or stacked vapor deposition (not shown).

  FIG. 16 shows a cross-sectional structure of the organic linear evaporation source 36 of FIG.

  Since the vapor deposition temperature of the organic linear evaporation source 36 is about 250 to 400 ° C., a stainless steel plate (SUS) is used for the base material 10 of the side surface / back surface reflector 4 and the front surface reflector 5, and silicon having a film thickness of 50 nm is used. Coating 11 was used. This prevents the side / back reflector 4 and the front reflector 5 from being oxidized due to long-time deposition in long-term production activities and repeated exposure to the atmosphere for material exchange, and the fluctuation in deposition rate is small. Stable production can be done. Further, the infrared radiation from the heater 3 is confined in the organic linear evaporation source 36 and the heat radiation from the front reflector 5 is also suppressed, so that the heat radiation from the organic linear evaporation source 36 to the substrate and the metal mask is reduced. As a result, the thermal expansion of the metal mask can be suppressed, and highly accurate patterning deposition can be performed stably.

  FIG. 17 schematically shows a metal deposition chamber (also referred to as “deposition chamber”) in the metal cluster 40 of FIG.

  This figure shows an example of a side deposition method in which a film is formed with the substrate 51 standing substantially vertically.

  The metal vapor deposition chamber 41 generally includes a gate valve 33, a substrate transfer unit 35, a substrate for maintaining a vacuum between the processing vacuum chamber 52 (also simply referred to as “vacuum chamber”) and a robot chamber (not shown). 51, a drive unit 53 for standing substantially vertically, a frame mask 57 for patterning a metal film for each panel, a metal linear evaporation source 58 arranged in a horizontal direction, and a metal point evaporation in which a plurality of point evaporation sources are arranged in a horizontal direction The source 59 is configured.

  The metal linear evaporation source 58 is a scanning method in which a film is formed on the entire surface of the substrate 51 by being arranged longer than the horizontal side of the substrate 51 and scanning in the height direction of the substrate 51. The metal point evaporation source 59 is a scanning method in which a plurality of point evaporation sources are arranged side by side longer than the horizontal side of the substrate 51, and a film is formed on the entire surface of the substrate 51 by scanning in the height direction of the substrate 51. The metal linear evaporation source 58 and the metal point evaporation source 59 may have, for example, a combination of upper and lower stages so that magnesium and silver can be co-evaporated or silver can be deposited on the layer.

  The cross-sectional structure of the metal linear evaporation source 58 is basically the same as that shown in FIG. Also, the metal point evaporation source 59 has a cross-sectional structure as shown in FIG. 17, but has a structure in which the depth direction of the paper surface is short and a plurality of metal point evaporation sources 59 are arranged in the depth direction.

  The metal linear evaporation source 58 is used, for example, when vapor-depositing magnesium, and since the vapor deposition temperature is about 400 ° C., a stainless steel plate (SUS) is used as the base material of the side surface / back surface reflector and front surface reflector. A silicon film having a thickness of 50 nm is used. On the other hand, the metal point evaporation source 59 is used for, for example, silver vapor deposition, and the vapor deposition temperature exceeds 1000 ° C. Therefore, a molybdenum plate (Mo) is used for the base material of the side surface / back surface reflector and front surface reflector, A silicon film with a thickness of 50 nm is used. This prevents the side and back reflectors and front reflectors from being oxidized due to long-term deposition during long-term production activities and repeated exposure to the atmosphere for material replacement, and is stable with little fluctuation in deposition rate. Can do production.

  In addition, infrared radiation from the heater in the evaporation source is confined, and heat radiation from the front reflector is also suppressed, so that heat radiation from the evaporation source to the substrate 51 and the frame mask 57 is reduced. Thereby, it is possible to carry out stably while suppressing the deterioration of the organic film on the substrate 51.

  Further, since the metal linear evaporation source 58 and the metal point evaporation source 59 are operated at a higher temperature than the organic linear evaporation source, it takes much time for cooling for material replacement. If the side and back reflectors and front reflectors of the present invention are used, the metal linear evaporation source 58 and the metal point evaporation source 59 are still in a high temperature state just after the heater is turned off. Even so, the metal vapor deposition chamber 52 can be leaked with nitrogen. By introducing nitrogen gas, the heat transfer by heat conduction and convection conduction can greatly reduce the cooling time compared to heat radiation of the metal linear evaporation source 58 and the metal point evaporation source 59 with only heat radiation in a vacuum state. It can be. Therefore, it is possible to shorten the material exchange time and improve the productivity of the vapor deposition apparatus.

  According to the evaporation source and the evaporation apparatus of the present invention, even if the evaporation source is operated for a long time, an increase in heater power and an increase in heat radiation to the substrate can be prevented, and stable evaporation with a low power consumption can be performed for a long time. . Moreover, the cooling rate of the evaporation source at the time of material exchange can be increased, and productivity can be improved.

  1: crucible, 2: nozzle, 3: heater, 4: side and back reflector, 5: front reflector, 10: base material, 11: coating, 12: surface layer, 13: interface layer, 14: intermediate layer, 20: organic cluster, 21: cassette, 22: load chamber, 23: substrate relay chamber, 24: robot chamber, 25: hole injection layer deposition chamber, 26: hole transport layer deposition chamber, 27: red light emitting layer deposition chamber, 28 : Green light emitting layer deposition chamber, 29: Blue light emitting deposition chamber, 30: Hole blocking layer deposition chamber, 31: Electron transport layer deposition chamber, 32: Electron injection layer deposition chamber, 33: Gate valve, 34: Transfer robot, 35: Substrate delivery unit, 36: organic linear evaporation source, 40: metal cluster, 41: metal evaporation chamber, 42: metal linear evaporation source, 43: metal point evaporation source, 44: unload chamber, 50: organic evaporation chamber, 51: Substrate, 52 Processing vacuum chamber, 53: driver, 54: metal mask 57: the frame mask, 58: metal linear evaporation source, 59: a metal point evaporation source.

Claims (9)

  A crucible for storing a vapor deposition material, a nozzle connected to the crucible and through which the vapor of the vapor deposition material passes, a heater for heating the crucible, a plurality of side surface / back surface reflectors surrounding the crucible and the heater, A plurality of front surface reflectors arranged around the nozzle, the side surface / back surface reflector and the front surface reflector include a base material and a coating provided on the surface of the base material, An evaporation source comprising silicon, silicon oxide, silicon nitride, or a composite compound thereof, or a compound of a metal element and silicon constituting the substrate.   A crucible for storing a vapor deposition material, a nozzle connected to the crucible and through which the vapor of the vapor deposition material passes, a heater for heating the crucible, a plurality of side surface / back surface reflectors surrounding the crucible and the heater, A plurality of front surface reflectors arranged around the nozzle, wherein the crucible and / or the nozzle includes a base material and a coating provided on the surface of the base material, the coating comprising silicon alone, silicon oxide Alternatively, an evaporation source comprising silicon nitride or a composite compound thereof, or a compound of a metal element and silicon constituting the substrate.   The coating has a layer containing silicon oxide, silicon nitride, or a composite compound thereof, and a layer of silicon alone, and the surface layer of the coating is composed of a layer containing silicon oxide, silicon nitride, or a composite compound thereof. The evaporation source according to claim 1, wherein   The metal thin film with higher infrared reflectivity than the said base material is provided between the said base material and the said film | membrane of the said side surface / back surface part reflector and the said front surface part reflector. The source of evaporation.   The evaporation source according to claim 2, wherein a thin film having an infrared absorption rate higher than that of the base material is provided between the base material and the coating film of the crucible and / or the nozzle.   An interface layer containing a compound of the metal element or the element constituting the metal thin film and silicon is formed between the substrate and the layer of silicon alone, silicon oxide, silicon nitride, or a composite compound thereof. The evaporation source according to any one of claims 1 to 5, wherein:   The evaporation source according to claim 1, wherein the thickness of the coating is 25 nm to 200 nm.   A vacuum chamber, and an evaporation source installed inside the vacuum chamber. The evaporation source includes a crucible for storing a vapor deposition material, a nozzle connected to the crucible and through which the vapor of the vapor deposition material passes, and the crucible. A heater for heating, a plurality of side and back reflectors surrounding the crucible and the heater, and a plurality of front reflectors disposed around the nozzle, the side and back reflectors and the front part The reflector includes a base material and a coating provided on the surface of the base material, and the coating includes silicon alone, silicon oxide or silicon nitride, or a composite compound thereof, or a metal element and silicon constituting the base material. The vapor deposition apparatus characterized by including the compound of these.   A vacuum chamber, and an evaporation source installed inside the vacuum chamber. The evaporation source includes a crucible for storing a vapor deposition material, a nozzle connected to the crucible and through which the vapor of the vapor deposition material passes, and the crucible. A heater for heating, a plurality of side and back reflectors surrounding the crucible and the heater, and a plurality of front reflectors arranged around the nozzle, the crucible and / or the nozzle being a base And a coating provided on the surface of the base material, and the coating contains a simple substance of silicon, silicon oxide or silicon nitride, or a composite compound thereof, or a compound of a metal element constituting the base material and silicon. The vapor deposition apparatus characterized by the above-mentioned.

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