JP4281029B2 - Evaporation source - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to an evaporation source, and more particularly, to an evaporation source that is used in a film forming apparatus for forming a thin film on a substrate by evaporating a high vapor pressure material in a vacuum vessel, and is applied to a production apparatus and applying the principle of resistance heating. Regarding the source.
[0002]
[Prior art]
A conventional evaporation source used in a film formation apparatus (evaporation apparatus) that forms a film on a substrate by evaporating a high vapor pressure material (organic material for organic EL, etc.) includes a resistance heating evaporation source using a resistor, a crucible Is roughly divided into cell-type evaporation sources with heating wires around them. A conventional resistance heating evaporation source and cell type evaporation source will be described with reference to the drawings.
[0003]
FIG. 6 shows a typical configuration of a resistance heating evaporation source. As shown in FIG. 6, a resistance heating evaporation source 72 is provided at a lower position in a vacuum vessel 71 forming a film forming apparatus, and a substrate 74 supported by a holder 73 is arranged at an upper position. The holder 73 has a ring shape, and the lower surface of the substrate 74 faces downward, and a high vapor pressure material that evaporates and arrives from below is formed on the lower surface. In the vicinity of the substrate 74, a detector 76 of a quartz vibrator type film thickness meter 75 that outputs a detection signal for controlling the evaporation amount of the material in the resistance heating evaporation source 72 is disposed. The evaporated particles emitted from the resistance heating evaporation source 72 as indicated by the arrow 77 adhere to the detector 76 of the film thickness meter 75 in addition to the lower surface of the substrate 74. The resistance heating evaporation source 72 includes a lower boat-like resistor 78, an upper lid-like resistor 79, and a plate-like resistor 80 interposed therebetween, and the three resistors are illustrated. The two end portions are sandwiched and fixed by the electrode portions 81 and 82. The boat-like resistor 78 functions as a container for filling the evaporation material 83. The lid-like resistor 79 and the plate-like resistor 80 are formed with blowing holes 79a and 80a through which the evaporated particles of the evaporation material 83 pass. A current is supplied from the power source 84 via the electrode portions 81 and 82 to the resistors 78, 79, and 80 of the resistance heating evaporation source 72, and the resistors generate heat. The amount of current supplied from the power supply 84 is controlled based on the detection signal from the film thickness meter 75. When the resistors 78, 79, and 80 generate heat, the evaporation material 83 filled in the boat-like resistor 78 starts to evaporate at a temperature specific to the material. The evaporated particles of the evaporation material 83 are discharged into the space around the resistance heating evaporation source 72 through the blowing holes 80a and 79a formed in the resistors 80 and 79. The evaporated particles thus discharged are deposited on the lower surface of the substrate 74 and the lower surface of the detector 76 as described above. The quartz vibrator type membrane pressure meter 75 is a device that controls the evaporation amount by utilizing the fact that the oscillation frequency changes due to the evaporation particles adhering to the detector 76. The film thickness meter 75 sends a signal to the power source 84 via a signal cable so as to obtain a desired evaporation amount while monitoring the amount of evaporated particles adhering to the detector 76, and changes the output of the power source 84 to change the resistance. The amount of heat generated by the bodies 78 to 80 is changed, and the amount of evaporation of the evaporation material 83 is controlled.
[0004]
Next, FIG. 7 shows a typical configuration of a cell type evaporation source. In FIG. 7, elements that are substantially the same as those described in FIG. 6 are given the same reference numerals. As shown in FIG. 7, in the vacuum vessel 71 forming the film forming apparatus, a cell type evaporation source 85 is provided at a lower position, and a substrate 74 supported by a holder 73 is arranged at an upper position. The lower surface of the substrate 74 faces downward through the holder 73, and a high vapor pressure material that evaporates and arrives from below is formed on this lower surface. The cell type evaporation source 85 is composed of a crucible 86 and a heating wire 87 wound around the lower portion of the crucible 86. When the current is passed from the power source 88 to the heating wire 87, the heating wire 87 generates heat, and the radiant heat generates the crucible. By raising the temperature of 86, the material 83 filled in the crucible 86 starts to evaporate at a temperature specific to the material. When the material of the crucible 86 is made of a substance that easily transmits infrared wavelengths, such as quartz, the material 83 is directly heated by radiant heat from the heating wire 87. The evaporated particles are discharged from the opening 86a of the crucible 86 into the space around the evaporation source as indicated by an arrow 89. Part of the emitted evaporated particles reaches the surface of the substrate 74. The amount of evaporation is controlled by monitoring the crucible temperature with a temperature controller 90 using a thermocouple installed outside the crucible 86 and changing the output of the power supply 88.
[0005]
[Problems to be solved by the invention]
The conventional resistance heating evaporation source has a small heat capacity of the resistor, has a good responsiveness to a temperature change of the material with respect to a change in the current value of the resistor, and has excellent controllability of the evaporation amount. On the other hand, since the form of the boat-like resistor 78 filled with the evaporation material is determined from the viewpoint of exhibiting such features, it is difficult to fill the evaporation material for a long time, and it is difficult to evaporate for a long time. It has the disadvantage that it is not suitable for the device.
[0006]
On the other hand, the conventional cell-type evaporation source has a feature that it is suitable for a production apparatus because it can structurally fill a large amount of evaporation material. However, since the amount of evaporation material is large, the heat capacity is large, and the evaporation of the material is controlled by heat radiation from the outside of the crucible, so that the response of the temperature change of the material to the change of the current value flowing through the heating wire 87. However, it is difficult to control at a particularly high evaporation rate. Further, since the temperature change of the outer peripheral portion of the crucible 86 is monitored, there is a disadvantage that the temperature of the material is different and the evaporation amount is different with the change of the amount of the material in the crucible.
[0007]
At present, the cell type is mainly used as the evaporation source from the viewpoint of the filling amount of the material suitable for the production apparatus. However, due to the above disadvantages, an evaporation source with higher controllability of evaporation rate is desired.
[0008]
An object of the present invention is to solve the above-described problem, and is an evaporation source that can be filled with a large amount of evaporation material and is suitable for a film forming apparatus for production, and that is excellent in controlling the evaporation amount with a high vapor pressure material such as an organic material. Is to provide.
[0009]
[Means and Actions for Solving the Problems]
The evaporation source according to the present invention is configured as follows to achieve the above object.
The first evaporation source (corresponding to claim 1) has a resistance heating container made of a resistor, and causes the current controlled by the detection signal from the film thickness meter to flow through the resistor to generate heat to evaporate the evaporation material. The resistance heating container includes an insulating material container filled with the evaporation material, and the material container has a lower opening. The lower opening is located inside the resistance heating container, and a gap is formed between the lower opening and the resistor.
The evaporation source according to the present invention has a configuration suitable as a production apparatus because a larger amount of evaporation material can be evaporated than a large-volume material container provided on the basis of the configuration of the resistance heating type evaporation source. Further, when a large amount of the evaporating material filled in the material container goes out of the material container, a part of the material comes into contact with the resistor and partially evaporates. This makes it possible to evaporate a large amount of evaporation material without bias. Furthermore, since the structure of the resistance heating evaporation source is utilized, it is possible to perform high control on the evaporation amount.
The second evaporation source (corresponding to claim 2) is that, in the first configuration, the resistance heating container is composed of a plate-shaped resistor and an upper lid resistor, and the upper lid resistor is provided with a material container and has an outlet hole. The lower opening of the material container is formed so as to be close to the plate resistor. The material container filled with the evaporation material is arranged upside down, and the lower opening of the material container is provided close to the plate resistor. The evaporating material in the material container moves downward, and the evaporating material located on the lowermost side contacts the plate resistor.
According to a third evaporation source (corresponding to claim 3), in the first configuration, the resistance heating container includes an upper lid resistor including a material container, a boat-shaped resistor having a blowout hole, and an upper lid resistor. It consists of a plate-like resistor provided between the boat-like resistors and having a passage hole for evaporated particles, and is configured such that the lower opening of the material container is provided close to the plate-like resistor. According to this configuration, an evaporation source having a deposition down structure suitable for a production apparatus is realized, which includes a material container that can be filled with a large amount of evaporation material.
Fourth evaporation source (corresponding to claim 4) has a resistance heating vessel comprising a resistor, in the evaporation source emitting vapor particles from the outlets provided in the resistance heating vessel further resistive heating vessel evaporation comprising an insulating material container to be filled with material, the material container has a top opening, the upper opening is provided inside the resistance heating vessel, and the resistance heating vessel upper lid resistor having a blow hole Body, a boat-like resistor having a material container, and a plate-like resistor provided between the upper lid resistor and the boat-like resistor and having a passage hole for evaporated particles, the upper opening of the material container being a plate The heat generating line is provided in the material container so as to generate heat by the current controlled by the detection signal from the temperature controller and evaporate the evaporation material. This evaporation source combines a resistance heating structure and a cell type structure, prepares a large amount of evaporation material, is suitable for a production apparatus, and can increase the control of the evaporation amount of the evaporation material.
In the fifth evaporation source (corresponding to claim 5 ), the material container is preferably an insulating crucible in each of the above configurations.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[0011]
1 to 3 show a first embodiment of an evaporation source according to the present invention. FIG. 1 shows the appearance of the container portion as viewed obliquely from above, FIG. 2 shows the internal structure, and FIG. 3 shows a cross-sectional view taken along line AA in FIG. The evaporation source according to this embodiment has a configuration in which a resistance heating evaporation source is applied. The evaporation source container 11 is a resistance heating container including a plate-like resistor 12 that forms the bottom and an upper lid resistor 13. In the plate resistor 12, a partition wall 14 is formed at the center. The upper lid resistor 13 is provided with a long material container 15 that has the same form as a lid-like resistor of a conventional resistance heating evaporation source and that stands up on one side in the longitudinal direction. Yes. The plate resistor 12 and the upper lid resistor 13 are made of a refractory metal (tungsten, molybdenum, etc.) that generates heat when an electric current is passed, and the material container 15 is made of, for example, insulating quartz. As shown in FIG. 2, the upper end of the material container 15 is closed and the lower end is open. The opening at the lower end is used as an opening for filling the material container 15 with the evaporating material 16 and as an opening for taking out the evaporating material 16 when evaporating. The plate resistor 12 and the upper lid resistor 13 are used as overlapped as shown in FIG. The material container 15 provided in the upper lid resistor 13 has an opening at the lower end thereof approaching the plate resistor 12 so that a desired gap is formed when they are overlapped. The length of the material container 15 is determined in accordance with the amount of the evaporation material 16 to be filled. When the plate resistor 12 and the upper lid resistor 13 are overlapped to form the evaporation source container 11, the material container 15 is positioned on one side (left side in FIG. 2) of the partition wall 14 of the plate resistor 12. Is configured to do. In addition, the upper lid resistor 13 has, for example, one blowout hole 17 for discharging particles evaporated from the evaporation material 16 to the surrounding space of the container 11 at a portion opposite to the material container 15 with the partition wall 14 as a boundary. Is formed. A gap 18 is formed between the partition wall 14 of the plate resistor 12 and the upper lid resistor 13. The evaporated particles move as indicated by the arrow 19 and are discharged from the blowout hole 17. The reason why the partition plate 14 is provided is that the conductance of the passage of the evaporated particles is reduced to create a pressure gradient. When a pressure gradient is applied, the diffusion of evaporated particles becomes significant.
[0012]
As shown in FIG. 2, the overlapped plate resistor 12 and upper lid resistor 13 are overlapped at both ends and fixed by the electrode portions 20 and 21. Each of the electrode portions 20 and 21 has a structure in which two plate members are stacked and fixed with screws or the like, whereby the both ends are sandwiched and fixed. As shown in the figure, the plate resistor 12 and the upper lid resistor 13 are held in contact with their peripheral portions, but the evaporation material 16 that melts and evaporates on the plate resistor 12 does not leak to the outside. Thus, both are held in a sealed state. In order to make this sealed state, it is also preferable to provide a folded portion at the edge of the plate resistor 12 or the upper lid resistor 13.
[0013]
The evaporation source having the above configuration is used in an apparatus similar to the conventional film forming apparatus described with reference to FIG. That is, a current is supplied from the power source 22 to the plate resistor 12 and the upper lid resistor 13 as the evaporation source through the electrode portions 20 and 21. When a current flows through the plate resistor 12 and the upper lid resistor 13, of the large amount of evaporation material 16 filled in the material container 15, the material is melted from the portion of the evaporation material located at the lowest position in contact with the plate resistor 12. Then evaporate. The evaporated particles move as indicated by an arrow 19 and are discharged from the blowout hole 17 to the surrounding space. Evaporated particles discharged from the blowout holes 17 of the upper lid resistor 13 of the container 11 rise, adhere to the lower surface of the substrate 74 and form a film as shown in FIG. The amount of evaporation of the evaporation material 16 in the evaporation source is controlled in the same manner as before, and is controlled by adjusting the amount of current flowing through the resistor based on the detection signal from the quartz crystal thin film meter. According to the evaporation source according to the present embodiment, since a large amount of evaporation material can be filled and the evaporation material is gradually evaporated from the lower evaporation material, continuous film formation for a long time becomes possible, and the production apparatus In addition to being usable, it is possible to appropriately control the evaporation amount and to perform evaporation with low power.
[0014]
In the above embodiment, it is also possible to provide a structure in which the upper portion of the material container 15 is opened and the evaporation material 16 can be appropriately supplied.
[0015]
A second embodiment of the evaporation source according to the present invention will be described with reference to FIG. This embodiment is a modification of the first embodiment, and FIG. 4 corresponds to FIG. The evaporation source according to this embodiment has a deposition down structure that emits evaporated particles downward. In FIG. 4, the same elements as those described in the above embodiment are denoted by the same reference numerals. The evaporation source container (resistance heating container) 31 includes an upper lid resistor 32, a boat-like resistor 33 that forms a lower portion of the container, and a plate-like resistor 34 located in the middle thereof. . The basic form of the upper lid resistor 32 and the plate resistor 34 is similar to that of the first embodiment. The basic form of the boat-like resistor 33 is similar to that of the prior art. The upper lid resistor 32 is provided with the material container 15 described above at a substantially central position. At least two holes 35 as passages for the evaporated particles are formed on both sides of the plate resistor 34. At least one blowing hole 36 is formed in the approximate center of the boat-like resistor 33. The point that the material container 15 is filled with a large amount of the evaporation material 16 and the point that the material container 15 partially evaporates from the lower part of the evaporation material 16 are the same as in the first embodiment. Other configurations are the same as those described in the first embodiment.
[0016]
According to the present embodiment, a resistance heating evaporation source having a deposition down structure can be realized, and further, the same effect as that of the first embodiment can be exhibited. That is, it can be filled with a large amount of evaporation material, can be continuously formed for a long time, can be used in a production apparatus, and the evaporation amount can be controlled appropriately.
[0017]
The structures according to the first and second embodiments described above are particularly effective for sublimable substances such as organic materials. Further, by adjusting the gap between the material container 15 and the plate-like resistor 12 or the gap between the material container 15 and the plate-like resistor 34, the molten material 16 is the same without flowing out due to the effect of surface tension. An effect is obtained.
[0018]
Next, a third embodiment of the evaporation source according to the present invention will be described with reference to FIG. The evaporation source according to this embodiment is configured by combining the structure of the resistance heating evaporation source and the structure of the cell type evaporation source. FIG. 5 shows the configuration of the evaporation source and the configuration of the system for controlling evaporation. In FIG. 5, elements that are substantially the same as those described in the above-described embodiments are denoted by the same reference numerals.
[0019]
In a vacuum container 41 forming a film forming apparatus, an evaporation source 42 according to the present embodiment is provided at a lower position, and a substrate 44 supported by a ring-shaped holder 43 is disposed at an upper position. The lower surface of the substrate 44 on the holder 43 faces downward, and a high vapor pressure material is deposited on this lower surface. In the vicinity of the substrate 44, a detector 46 of a quartz vibrator type film thickness meter 45 that outputs a detection signal for controlling the amount of evaporation of the material in the evaporation source 42 is disposed. The evaporated particles emitted from the evaporation source 42 adhere to the lower surface of the substrate 44 and the detection surface of the detector 46.
[0020]
The resistance heating container of the evaporation source 42 includes an upper lid resistor 47, a lower boat resistor 48, and a plate resistor 49 interposed therebetween, and the three resistors are illustrated. They are overlapped as they are, and both end portions are sandwiched and fixed by the electrode portions 20 and 21 described above. The boat-like resistor 48 is provided with a material container 15 that can be filled with a large amount of the evaporation material 16 at a substantially central position. The material container 15 is used so that the opening is located on the upper side. The upper lid resistor 47 and the plate-like resistor 49 are formed with blowout holes 50 and 51 through which evaporated particles from the evaporation material 16 pass. A current is supplied from the power source 52 to the resistors 47, 48, and 49 of the evaporation source 42 through the electrode portions 20 and 21, and heat is generated. The amount of current supplied from the power source 52 is controlled based on the detection signal from the film thickness meter 45. A desired gap is formed between the upper end opening of the material container 15 and the plate resistor 49 in a state where the resistors 47, 48 and 49 are assembled as shown in the figure.
[0021]
The material container 15 has a sufficient volume to accommodate the required evaporation material 16 and is made of, for example, quartz. A configuration of a cell type evaporation source is further added to the configuration related to the material container 15. That is, the material container 15 functions as a crucible, and a heating wire 53 is wound around the lower portion. The heating wire 53 is connected to a power source 54. When a current flows from the power source 54 to the heating wire 53, the heating wire 53 generates heat, and the material container 15 is filled by raising the temperature of the material container 15 by the radiant heat. The evaporated material 16 evaporates at a temperature specific to the material. Further, since the material container 15 is made of quartz that easily transmits infrared wavelengths, the evaporation material 16 is directly heated by radiant heat from the heating wire 53. The evaporated particles are discharged from the upper end opening of the material container 15. The amount of evaporation from the material container 15 is controlled by monitoring the temperature with a temperature controller 55 using a thermocouple installed outside the material container 15 and changing the output of the power supply 54.
[0022]
Further, the evaporated particles discharged from the upper end opening of the material container 15 pass through the blowing hole 51 of the plate resistor 49 and the blowing hole 50 of the upper lid resistor 47 as shown by the arrow 56 and are discharged to the external surrounding space. The At this time, the resistors 47, 48 and 49 are in a heat generating state. The evaporated particles thus released are deposited on the lower surface of the substrate 44 and the detection surface of the detector 46 of the film thickness meter 45 as described above. The quartz vibrator type membrane pressure gauge 45 controls the evaporation amount by utilizing the fact that the oscillation frequency changes due to the evaporation particles adhering to the detector 46. The film thickness meter 45 sends a signal to the power source 52 so as to achieve a desired evaporation amount while monitoring the amount of evaporated particles adhering to the detector 46, and changes the output of the power source 52 to change the resistances 47 and 48. , 49 is changed, and the evaporation amount of the evaporation material 16 is controlled.
[0023]
According to the third embodiment, the evaporating material 16 filled in the material container 15 starts to evaporate at its own temperature based on the heat generating action of the heating wire 53. The evaporated particles from the evaporation material 16 adhere to the surface of the boat-like resistor 48 and the plate-like resistor 49 on the upper side of the material container 15, but are evaporated again by receiving heat from these resistors, It moves like this and is discharged from the blowing hole 50 of the upper lid resistor 47 to the outside space. The emitted evaporated particles adhere to the substrate 44 and the detector 46. The quartz vibrator type membrane pressure gauge 45 sends a signal to the power source 52 based on the obtained information and changes its output, thereby changing the heat generation amount of the resistors 47, 48 and 49 and controlling the evaporation amount. Since the evaporation amount is controlled by the temperature change caused by direct current flow through the resistor, the responsiveness to the change in the evaporation rate is good, and more material can be filled in the material container 15, so that it can be used in production equipment. Suitable for
[0024]
【The invention's effect】
As is apparent from the above description, according to the present invention, a resistance heating container made of a resistor and a material container that can be filled with a large amount of evaporation material are combined. Since it is configured to come into contact with the resistor, the evaporation material can be stably evaporated for a long time, and the evaporation amount can be controlled effectively. Therefore, an evaporation source suitable for the production apparatus can be realized. Furthermore, an evaporation source having a deposition down structure can be obtained.
[Brief description of the drawings]
FIG. 1 is an external view of a container portion according to a first embodiment of an evaporation source according to the present invention, viewed obliquely from above.
FIG. 2 is a longitudinal sectional view showing the internal structure of the evaporation source according to the first embodiment.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a longitudinal sectional view showing an internal structure of an evaporation source according to a second embodiment of the present invention.
FIG. 5 is a block diagram showing the overall structure and apparatus of an evaporation source according to a third embodiment of the present invention.
FIG. 6 is a configuration diagram of a conventional resistance heating evaporation source.
FIG. 7 is a configuration diagram of a conventional cell type evaporation source.
[Explanation of symbols]
11 Container (resistance heating container)
12 Plate Resistor 13 Upper Lid Resistor 15 Material Container 16 Evaporating Material 17 Blowout Holes 20 and 21 Electrode Unit 31 Container (Resistance Heating Container)
32 Upper lid resistor 33 Boat resistor 34 Plate resistor 41 Vacuum container 42 Evaporation source 44 Substrate 46 Detector 47 Upper lid resistor 48 Boat resistor 49 Plate resistor 53 Heating wire

Claims (5)

Having a resistance heating container made of a resistor, a current controlled by a detection signal from a film thickness meter is caused to flow through the resistor to generate heat, evaporate the evaporation material, and evaporate particles from a blowout hole provided in the resistance heating container In the evaporation source that emits
Further, the resistance heating container includes an insulating material container filled with an evaporation material, and the material container has a lower opening,
The lower opening is located inside the resistance heating container, and a gap is formed between the lower opening and the resistor. The resistance heating container, a plate-shaped resistor and the upper lid resistor, said upper lid resistor, together with the material container is provided, wherein the outlet and the hole is formed, the lower opening of the material container, wherein The evaporation source according to claim 1, wherein the evaporation source is provided close to the plate resistor. The resistance heating container includes an upper lid resistor provided with the material container, a boat-like resistor having the blowout hole, and a passage hole for the evaporated particles provided between the upper lid resistor and the boat-like resistor. evaporation source composed of a plate-shaped resistor, the lower opening of the material container, characterized in that it is provided close to the plate shaped resistor claim 1 Symbol placement with. In an evaporation source having a resistance heating container made of a resistor and discharging evaporated particles from a blow-out hole provided in the resistance heating container,
Further, the resistive heating vessel comprising an insulating material container filling the evaporation material, said material container has an upper opening, the front SL upper opening, provided inside the resistance heating vessel,
The resistance heating container includes an upper lid resistor having the blowout hole, a boat-like resistor having the material container, and a passage hole for the evaporated particles provided between the upper lid resistor and the boat-like resistor. The upper opening of the material container is provided close to the plate resistor, and the material container generates heat with a current controlled by a detection signal from a temperature controller. An evaporation source, wherein a heating line for evaporating the evaporation material is provided .   The evaporation source according to any one of claims 1 to 4, wherein the material container is a crucible having insulating properties.

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