Film deposition device

Abstract

To reduce quality dispersion by restraining reduction of a non-defective rate of products due to flatness deterioration of a mask frame in an organic EL film deposition device.SOLUTION: A film deposition device fixes a mask having plural openings to a mask frame, and deposits a film on a substrate via the plural openings. The film deposition device comprises: a support part, which supports the mask frame and on which plural magnets are arranged; plural coils arranged at positions opposite to the plural magnets; plural sensors measuring the position of the mask or the mask frame; and a control part deforming the support part and the mask frame by controlling a current applied to each of the plural coils according to a measurement value of each of the plural sensors.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a film forming apparatus, and more particularly to a method for floating and aligning a mask in a mask film forming apparatus for an organic electroluminescence display. [Background technology]

[0002] A known method for manufacturing organic EL displays is the mask deposition method, in which a predetermined pixel pattern is formed by depositing an organic thin film on a substrate by vacuum deposition through a mask with openings formed in a predetermined pattern. In the mask deposition method, the mask and substrate are aligned, and then the mask and substrate are brought into close contact with each other to deposit the film.

[0003] Generally, masks for OLED displays are often thin foils that cannot maintain their shape by themselves, so the mask is fixed in place by applying tension to a metal frame called a mask frame.

[0004] In recent years, substrates have tended to become larger in size to improve productivity, and a technique using an electrostatic chuck in a substrate gripping mechanism to suppress bending of the substrate is known. In addition, in terms of improving alignment accuracy and suppressing dust generation, a technique is known in which the mask side is driven using a magnetic levitation stage in order to align the mask and substrate. The magnetic levitation stage has a simple structure and can be driven in XYΘ directions, so that alignment can be easily performed even if the substrate side is tilted for some reason. Patent Document 1 discloses a technique for correcting the tilt of a levitation body (mask) relative to a workpiece (substrate). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 05-276608 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, the trend towards larger substrates has led to corresponding larger masks. In particular, mask frames have a problem of poor flatness due to residual internal stress in the metal when manufacturing large metal frames and machining precision.

[0007] When the flatness of the mask frame deteriorates, the flatness of the attached mask also deteriorates. When the flatness of the mask deteriorates, a gap occurs between the substrate and the mask, which causes film blurring during film formation and reduces the yield rate. In addition, because the mask is periodically replaced within the device, if there is a difference in flatness between different masks, the product quality will vary due to the above-mentioned reason.

[0008] The present invention has been made in view of the above problems, and aims to suppress a decrease in the yield rate of products caused by deterioration of the flatness of a mask frame in an organic EL film forming apparatus, and to reduce the quality variation of products. [Means for solving the problem]

[0009] The present invention employs the following configuration. A film forming apparatus that fixes a mask having a plurality of openings to a mask frame and forms a film on a substrate through the plurality of openings, a support portion supporting the mask frame and having a plurality of magnets arranged thereon; A plurality of coils arranged in positions facing the plurality of magnets; a plurality of sensors for measuring the position of the mask or mask frame; a control unit that controls a current applied to each of the coils in response to measurement values ​​of the respective sensors to deform the support unit and the mask frame; The film forming apparatus is characterized by comprising: Effect of the Invention

[0010] According to the present invention, in an organic EL film forming apparatus, it is possible to suppress a decrease in the yield rate of products caused by deterioration in the flatness of a mask frame, and reduce the variation in product quality. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic perspective view of a film forming apparatus according to a first embodiment; [Diagram 2] Cross-sectional view of the inside of the chamber of the film forming apparatus [Diagram 3] 1 is a cross-sectional view of the inside of the chamber of the film forming apparatus in a different direction. [Figure 4] Cross-sectional view of the inside of the chamber when the mask frame is deformed [Diagram 5] 1 is a cross-sectional view of the inside of the chamber after the mask frame has been corrected. [Figure 6] 11 is a cross-sectional view of the inside of a chamber of a film forming apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. The following embodiments do not limit the invention according to the claims. Although the embodiments describe a plurality of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the accompanying drawings, the same or similar configurations are given the same reference numbers, and duplicated descriptions are omitted. That is, the following embodiments merely exemplify preferred configurations of the present invention, and the scope of the present invention is not limited to these configurations. Furthermore, the hardware and software configurations, processing flows, manufacturing conditions, dimensions, materials, shapes, and the like of the devices in the following description are not intended to limit the scope of the present invention to these configurations alone, unless otherwise specified.

[0013] The present invention is suitable for a film formation apparatus that forms a thin film of a film formation material on a surface of a film formation target such as a substrate. The present invention can be understood as a film formation method using such a film formation apparatus, or a control method for such a film formation apparatus. The present invention can also be understood as an electronic device manufacturing apparatus, a control method thereof, and a manufacturing method for an electronic device. The present invention can also be understood as a program for causing a computer to execute the control method, or a storage medium storing the program. The storage medium may be a non-transitory storage medium readable by a computer.

[0014] The substrate material in the present invention may be any of glass, resin, metal, silicon, etc. The film-forming material may be any of organic materials, inorganic materials (metal, metal oxide), etc. The present invention is particularly suitable for inspecting and evaluating organic films formed from organic materials. In the following description, the term "substrate" includes substrate materials on whose surfaces one or more films have already been formed. The technology of the present invention is typically applied to manufacturing equipment for electronic devices and optical components. In particular, the technology is suitable for organic electronic devices such as organic EL displays equipped with organic EL elements and organic EL display devices using the same. The present invention can also be used in thin-film solar cells and organic CMOS image sensors.

[0015] [First embodiment] (Device configuration) 1, 2 and 3 are schematic diagrams showing the overall configuration of a film forming apparatus and a mask floating method according to the present invention. FIG. 1 is a schematic perspective view of a film forming apparatus 100 (the chamber is omitted). FIG. 2 is a cross-sectional view of the inside of the chamber as viewed from the direction of the arrow A in FIG. 1. FIG. 3 is a cross-sectional view of the inside of the chamber as viewed from the direction of the arrow B in FIG. 1. 1 is a cross-sectional view of the inside of the chamber as viewed from the front.

[0016] The film forming apparatus 100 has a chamber 1 which is a film forming chamber. The film forming apparatus 100 may have a plurality of film forming chambers. By having a plurality of film forming chambers, different types of films can be formed in each film forming chamber, and film forming can be performed on a plurality of lines to improve tact time. A mechanism using magnetic levitation as described later can be suitably used as a transport mechanism for transporting the substrate between the film forming chambers. In addition, a transport mechanism such as a robot arm may be used in combination. The film forming apparatus 100 may further include a transport chamber used for transporting and transferring the substrate, a rotation chamber for inverting the substrate, a substrate stock chamber for stocking the substrate, a mask stock chamber for stocking the mask, an evaluation chamber for evaluating the film formation status of the substrate, and the like.

[0017] The deposition apparatus 100 preferably further includes a control unit 101 that performs electrical and mechanical control related to transportation and deposition, and functions as an interface with a user. The control unit 101 is preferably a computer or control circuit equipped with a processor, memory, etc.

[0018] In the figure, reference numeral 1 denotes a chamber, reference numeral 2 denotes an electrostatic chuck which holds the substrate, reference numeral 3 denotes a sensor which measures the position of the mask or frame, reference numeral 4 denotes a substrate, reference numeral 5 denotes a coil, reference numeral 6 denotes a mask stage which is a support part for supporting the mask frame, reference numeral 7 denotes a mask, reference numeral 8 denotes a mask frame, reference numeral 9 denotes a magnet, reference numeral 10 denotes a seating base for the mask stage, and reference numeral 11 denotes an evaporation source. The mask 7 which has minute apertures arranged in a predetermined pattern is fixed to the mask frame 8.

[0019] The chamber 1 is maintained in a high vacuum state during the manufacturing process. The electrostatic chuck 2 is a substrate holder that comes into contact with one of the two surfaces of the substrate 4 opposite to the surface that comes into contact with the mask 7, and attracts and holds the substrate 4 by electrostatic attraction. The electrostatic chuck 2 has a structure in which an electric circuit such as a metal electrode is embedded in a plate-shaped base material made of ceramic or the like, and any type of electrostatic chuck can be used, such as a gradient force type, a Coulomb force type, or a Johnsen-Rahbek force type.

[0020] The sensor 3 is a measuring means for measuring the position of the mask 7 or the mask frame 8. The measurement position and measurement object of the sensor 3 are not particularly limited as long as it can measure the position of the mask 7 or the mask frame 8 and output a measurement value. The measurement method is also not particularly limited, and for example, an optical sensor method or a laser detection method can be adopted.

[0021] The substrate 4 is held by an electrostatic chuck 2 and fixed to the chamber 1 side. The mask 7 attached to a mask frame 8 is aligned with reference to the substrate 4 or the electrostatic chuck 2. The mask frame 8 and mask 7 are placed on a mask stage 6, on which a plurality of magnets 9 are arranged. A plurality of coils 5 fixed to the chamber side are arranged in positions facing the plurality of magnets 9. The magnetic force is controlled by controlling the current flowing through each of the plurality of coils 5, and the mask 7 and mask frame 8 are levitated together with the mask stage 6, and are slightly moved in the XYΘ directions.

[0022] The position of the mask relative to the substrate is observed by an alignment camera (not shown) and fed back to the coil currents for levitation and XYΘ fine movement to align the mask with respect to the substrate. The alignment camera is, for example, an optical camera arranged above the chamber 1, capturing an image of the downward direction through a peephole in the ceiling of the chamber, and acquires the relative positional relationship between the substrate alignment mark provided on the substrate 4 and the mask alignment mark provided on the mask 7 (or mask frame 8). Note that in this embodiment, an example has been shown in which the mask frame is levitated (raised and lowered) by a plurality of magnets and a plurality of coils arranged on the mask stage 6, but this is not limiting. For example, the mask stage may be supported by receiving claws, and the mask stage may be raised and lowered by a drive unit that raises and lowers the receiving claws. Note that an actuator (not shown) may be connected to the electrostatic chuck 2. In that case, the driving of the mask stage 6 and In addition, by moving the substrate 4 together with the electrostatic chuck 2 in the XY directions, the Θ rotation direction, the Z direction, and the like, the accuracy of alignment between the substrate 4 and the mask 7 can be improved.

[0023] After completing the alignment, the evaporation material is emitted from the evaporation source 11 toward the substrate 4. The evaporation material reaches the mask 7 through a large opening in the mask stage 6, and then reaches the substrate through small openings provided in a predetermined pattern on the mask 7, where it is deposited. The evaporation source 11 is a film forming means including a container such as a crucible for containing the evaporation material (film forming material), a heater, a shutter, a driving mechanism, an evaporation rate monitor, and the like. Note that the film forming source is not limited to an evaporation source, and may be a sputtering device.

[0024] (Mask frame deformation) Assume that the mask frame 8 is deformed during the series of film formation operations described above. Figure 4 is a schematic diagram. Reference numeral 13 denotes the mask frame that is deformed in the levitated state, reference numeral 12 denotes the mask stage that is deformed following the deformation of the mask frame, reference numerals 91 to 94 denote magnets, reference numerals 51 to 54 denote coils, and reference numerals 31 to 34 denote sensors that measure the distance from the electrostatic chuck 2 to the upper end of the mask frame 13. Here, it is assumed that the mask frame 13 and the mask stage 12 have the same rigidity, and that the shape of one can follow the shape of the other.

[0025] 4, if the mask frame 13 is deformed, when the mask 7 and the substrate 4 are brought into close contact with each other, a gap will be generated between the mask 7 and the substrate 4 according to the deformed shape of the mask frame 13. In such a place, film blurring will occur during film formation, which may result in product defects.

[0026] Furthermore, the mask 7 has a number of minute openings in a predetermined pattern according to the film formation pattern. During film formation, evaporated material adheres to the opening edges, causing the openings to gradually narrow. Therefore, during production, the mask 7 and mask frame 13 are replaced and cleaned at regular intervals. The deformation of the mask frame 13 varies from one mask to another, and the deformed shape also changes with each cleaning. Therefore, the state of film blurring may change each time the mask 7 is replaced.

[0027] (Configuration of the present invention) In order to solve the above-mentioned problem, in the present invention, the deformation of the mask frame 13 is corrected by the following procedure. First, the state of deformation of the mask frame 13 is measured using sensors 31 to 34 that measure the distance from the electrostatic chuck 2 to the upper end of the mask frame 13. Since extremely high-order modes of the deformation of the mask frame 13 are difficult to observe in practice, in this embodiment, four sensors are provided per side to measure the deformation shape up to the second mode. The multiple sensors are arranged side by side on at least one side of the electrostatic chuck 2. Also, multiple sensors may be arranged side by side on each of two opposing sides of the electrostatic chuck 2. Also, sensors may be arranged on three or more sides. The number of sensors per side is not limited to four, and may be appropriately set according to the size of the mask frame 13 and the degree of deformation expected based on the composition.

[0028] While maintaining the levitated state, the control unit 101 changes the amount of current applied to each of the coils 51-54 in accordance with the difference in distance detected by the above sensors. At this time, the total amount (sum) of current flowing through the coils 51-54 is maintained. What is important here is that the positions of the sensors 31-34 that measure the distance from the electrostatic chuck to the upper end of the mask frame are close to the positions of the coils 51-54.

[0029] 4, the distance between the electrostatic chuck and the mask frame detected by the sensors 31 and 33 is relatively far, while the distance between the electrostatic chuck and the mask frame detected by the sensors 32 and 34 is relatively close. In response to this, the current flowing through the coils 51 and 53 is controlled to be large and the current flowing through the coils 52 and 54 is controlled to be small. At this time, the current flowing through the coils 51 to 54 is controlled to be large and the current flowing through the coils 51 to 54 is controlled to be small. The sum of the currents is not changed as much as possible, but this does not mean that a change within the margin of error is not allowed.

[0030] By performing the above control, it is possible to increase the magnetic attraction force acting between the coils 51 and 53 and the magnets 91 and 93. On the other hand, it is possible to decrease the magnetic attraction force acting between the coils 52 and 54 and the magnets 92 and 94. By changing the balance of the magnetic attraction forces acting on the mask stage 12 in this way, it is possible to deform the mask stage 12. If the mask stage 12 and the mask frame 13 have the same rigidity and the shape of one can imitate the shape of the other, it is possible to indirectly correct the deformation of the mask frame 13 by performing the above control.

[0031] On the other hand, when the mask frame 13 is raised and lowered by another means, the total current amount flowing through the magnets 91-94 and the coils 51-54 must be kept to a value at which the mask frame 13 does not levitate. Therefore, it may not be possible to completely suppress deformation depending on the mask frame 13. On the other hand, when the mask frame 13 is raised and lowered by the magnets 91-94 and the coils 51-54, it is preferable because control is easier since it is only necessary to change the amount of current flowing through each while maintaining the total amount of current (sum).

[0032] The above control is continued until the distances detected by the sensors 31 to 34 become equal and are allowed to settle. The result of performing the above control is shown in FIG. 5. In FIG. 5, reference numeral 15 denotes the mask frame after correction, and reference numeral 14 denotes the mask stage after correction. In the illustrated example, the detection distances by the sensors 31 to 34 do not exactly match, but are within a range that does not pose a problem in practice. In other words, it is sufficient that the detection distances by the sensors 31 to 34 are approximately equal to an extent that causes no problems in relation to alignment accuracy and film formation accuracy.

[0033] The above-described method makes it possible to correct the deformation of the mask frame, thereby making it possible to suppress film blurring caused by the deformation of the mask frame, as well as the resulting decrease in the yield rate of products and quality variations.

[0034] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to the drawings. The following mainly focuses on the differences from the first embodiment.

[0035] Here, the first embodiment will be considered. When the coils 51-54 are controlled in accordance with the detection distance of the sensors 31-34 that measure the distance from the electrostatic chuck 2 to the upper end of the mask frame, the larger the amplitude of the deformation of the mask frame, the larger the change in the current becomes. When the amount of current flowing through the coils increases, the heat generated by the coils increases, and ultimately, problems such as the coils burning out arise. Since the heat generated by the coils is proportional to the square of the amount of current, the amount of current ultimately determines the rate, and the range in which the mask frame deformation can be corrected is limited.

[0036] In such a case, it is effective to provide the coils 51 to 54 themselves with a mechanism for lifting in the z direction. Increasing the amount of current and lowering the position of the coils are equivalent in terms of changing the magnetic attractive force. Similarly, decreasing the amount of current and raising the position of the coils are also equivalent in terms of changing the magnetic attractive force.

[0037] The film forming apparatus 100 of this embodiment includes an elevation mechanism for individually raising and lowering each coil in the z direction. As the elevation mechanism, for example, a configuration using a ball screw and an actuator can be used.

[0038] The above example is shown in FIG. 6. The state shown in FIG. 4 is the state before correction. While maintaining the levitated state of the mask stage, i.e., while maintaining the total amount (sum) of current flowing through the coils 51-54, the heightwise positions of the coils 51-54 are changed according to the distance between the electrostatic chuck and the mask frame detected by the sensors 31-34. In the example of FIG. 6, the distance detected by the sensors 31 and 33 is farther, and the distance between the electrostatic chuck and the mask frame detected by the sensors 32 and 34 is closer. Correspondingly, the heightwise positions of the coils 51 and 53 are changed in a direction approaching the mask stage. On the other hand, the heightwise positions of the coils 52 and 54 are changed in a direction away from the mask stage. At this time, the sum of the currents flowing through 51-54 may be either unchanged or changed.

[0039] In this embodiment, even if the deformation of the mask frame is large, the above-mentioned method makes it possible to correct the deformation by adjusting the height direction of the coil, thereby making it possible to suppress film blurring caused by the deformation of the mask frame and the resulting decrease in the yield rate and quality variation of the product.

[0040] As described above, according to the embodiment of the present invention, in an organic EL film forming apparatus, it is possible to suppress a decrease in the yield rate of products due to deterioration in the flatness of the mask frame and reduce the quality variation of products. In addition, by correcting the flatness of the mask frame caused by the increase in size of the mask and mask frame, it is possible to improve the yield rate of products and reduce the quality variation. [Explanation of symbols]

[0041] 1: chamber, 2: electrostatic chuck, 3: sensor, 4: substrate, 5: coil, 6: mask stage, 7: mask, 8: mask frame, 9: magnet

Claims

1. A film forming apparatus for fixing a mask having a plurality of openings to a mask frame and forming a film on a substrate through the plurality of openings, comprising: a support portion that supports the mask frame and has a plurality of magnets disposed thereon; a plurality of coils disposed at positions facing the plurality of magnets; a plurality of sensors for measuring the position of the mask or the mask frame; a control unit that deforms the support portion and the mask frame so as to correct the flatness of the mask frame by controlling the current applied to each of the plurality of coils according to the measurement values of each of the plurality of sensors; A film forming apparatus, characterized by comprising the above.

2. The plurality of magnets are arranged side by side on at least one side of the support portion. The film forming apparatus according to claim 1, characterized by the above.

3. At least four or more magnets are arranged per side of the support portion. The film forming apparatus according to claim 1 or 2, characterized by the above.

4. The plurality of sensors measure the distance between the substrate and the support portion or the distance between the substrate and the mask frame at the positions of the plurality of coils respectively. The film forming apparatus according to claim 1 or 2, characterized by the above.

5. The control unit increases the current applied to the coil at a position where the distance measured by the sensor is relatively far, and decreases the current applied to the coil at a position where the distance measured by the sensor is relatively close. The film forming apparatus according to claim 4, characterized by the above.

6. The control unit maintains the sum of the currents applied to the plurality of coils before and after changing the current applied to the plurality of coils. The film forming apparatus according to claim 5, characterized by the above.

7. The plurality of magnets and the plurality of coils are used to raise and lower the support portion. The film forming apparatus according to claim 1 or 2, characterized by the above.

8. It has a lifting mechanism for lifting each of the plurality of coils. The film forming apparatus according to claim 1 or 2, characterized by the above.

9. The lifting mechanism moves the coil in a direction away from the support portion at a position where the distance measured by the sensor is relatively far, and moves the coil in a direction approaching the support portion at a position where the distance measured by the sensor is relatively close. The film forming apparatus according to claim 8, characterized by the above.

10. A film forming method comprising forming a film on a substrate through a mask using the film forming apparatus according to Claim 1 or 2.

11. A manufacturing method comprising manufacturing an electronic device using the film forming method according to Claim 10.

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