JP7695087B2 - Method for manufacturing deposition source - Google Patents

Description

The present invention relates to a method for manufacturing a deposition source.

In recent years, devices that allow users to experience virtual worlds such as AR, VR, or MR have been actively developed. For monitors that play video content on such devices, organic EL displays have been attracting attention because of their wide viewing angle, and organic EL displays are required to have a resolution of, for example, 2000 ppi or higher. As one method for manufacturing such organic EL displays, it is known to deposit organic light-emitting layers that emit red (R), green (G), and blue (B) fluorescence on the surface of a substrate to be processed by vacuum deposition with high resolution. The substrate to be processed is usually partitioned into minute deposition areas by PDL (generally, the size of a unit element composed of each RGB organic light-emitting layer is 1 inch square, and the so-called pixel pitch is about 12 μm), and each organic light-emitting layer is deposited in each of these partitioned deposition areas to suppress RGB bleeding, uneven brightness, and color mixing within each element.

A vacuum deposition apparatus that can be used for the above-mentioned purposes is known, for example, from Patent Document 1. This apparatus is equipped with a vacuum chamber, and multiple deposition sources are provided in the vacuum chamber. The deposition source has a long storage box in one direction, which is filled with a solid deposition material (organic material) corresponding to the fluorescence, and on the upper surface of the storage box facing the substrate to be processed, multiple cylindrical emission nozzles (emission parts) are arranged at intervals and protrude outward (so-called linear source). When the deposition material in the storage box is heated by a heating means in a vacuum chamber in a vacuum atmosphere, the sublimated or vaporized deposition material is emitted from the emission nozzle according to a predetermined cosine law. When an organic light-emitting layer is deposited in a partitioned deposition region using such a deposition source, if the interval between the emission nozzles is large, the number of emission nozzles that inject the deposition material and the incidence angle will change for each deposition region. For this reason, there is a problem that the film thickness of the organic light-emitting layer in each deposition region is likely to vary, which makes the performance of each element unstable. In such cases, multiple discharge nozzles can be installed close to each other on the top surface of the storage box, but when considering installation space and strength, there is a limit to the number of discharge nozzles with a given diameter that can be installed.

JP 2014-77193 A

In view of the above, the present invention aims to provide a method for manufacturing a deposition source that can form a large number of emission parts closely spaced on the surface facing the substrate to be processed.

In order to solve the above problems, the method for manufacturing an evaporation source of the present invention includes a step of forming a plurality of emission portions in a predetermined pattern on the upper surface of a storage box filled with an evaporation material, the emission portions allowing the passage of the evaporation material vaporized or sublimated by heating the storage box. The method is based on the premise that the method further includes a first step of providing a mask on the upper surface of the storage box to limit the etching range, with each emission portion formed in the predetermined pattern being an etching range, and a second step of etching the etching range of the storage box through the mask to form a plurality of through holes reaching the space within the storage box.

According to the present invention, for example, when the container is placed in the vacuum chamber of the vacuum deposition apparatus, the upper surface of the container box facing the substrate as the film formation target is constituted by through holes formed by etching, so that by simply selecting an appropriate mask pattern, a large number of discharge parts having a fine aperture and a smallest possible interval between adjacent ones can be densely formed on the upper surface of the container box. Here, the etching in the second step includes not only dry etching but also wet etching. In addition, in the present invention, the first step includes a step of forming a mask material layer on the upper surface of the container box, a step of applying a resist to the surface of the mask material layer, patterning it by lithography, and forming an opening leading to the upper surface of the container box in the mask material layer by etching using the patterned resist as a mask, and is characterized in that after the second step, the resist pattern is removed while the mask material layer is left on the upper surface of the container box without being removed. This makes it possible to lengthen the discharge part by the thickness of the mask material layer , which is advantageous in improving the linearity of the deposition material discharged from the discharge part.

In the present invention, when the container box is composed of a box part filled with the deposition material and a cover plate part detachably attached to the upper end of the box part, it is preferable that the cover plate part is a silicon substrate, and the first step may include a step of forming a mask material layer on the upper surface of the silicon substrate, a step of applying a resist on the mask material layer, patterning the resist by lithography, and a step of forming an opening leading to the through hole on the upper surface of the silicon substrate by etching using the patterned resist as a mask. This is advantageous because it allows the use of mask materials, etching solutions, or etching gases that are generally used in the manufacturing process of so-called semiconductor devices. Moreover, when the box part of the container box is heated to vaporize or sublimate the deposition material filled therein, the silicon substrate is heated to a high temperature and maintained by heat transfer from the box part, since the silicon substrate has a relatively high thermal conductivity. This prevents the deposition material from clogging the through holes as much as possible, even if the through holes as the release parts are formed to have a fine diameter. As the mask material layer, a silicon compound layer such as a silicon oxide layer, a silicon nitride layer, or a silicon oxynitride layer can be suitably used.

On the other hand, in the present invention, the first step includes a step of bonding the silicon substrate as the first silicon substrate to the upper surface of the first silicon substrate and heating the bonded silicon substrates at a predetermined temperature to bond them together, and a step of applying resist onto the second silicon substrate and patterning it by lithography, and the second step includes a step of forming through holes that communicate with each other in the vertical direction by etching using the patterned resist as a mask. This is advantageous because each emission section is composed of through holes that communicate with the first silicon substrate and the second silicon substrate, and therefore the emission section can be made longer by the thickness of each silicon substrate. In this case, multiple silicon substrates may be further bonded together.

In the present invention, it is also preferable that the top surface of the container box is divided into a plurality of areas, and the emission sections are provided in different patterns in each of these divided areas. This makes it possible to manufacture a deposition source that can use different emission sections depending on the type of substrate to be processed. In this case, the emission sections that are not used can be configured to be shielded, for example, by a shutter mechanism.

FIG. 4 is a cross-sectional view illustrating a container box as a component of the deposition source. 5A to 5D are cross-sectional views illustrating a method for manufacturing a cover plate as a component of the deposition source according to the first embodiment. 6A to 6D are cross-sectional views illustrating a method for manufacturing a cover plate as a component of the deposition source according to the second embodiment. 1 is a cross-sectional view illustrating a vacuum deposition apparatus including a deposition source manufactured by the manufacturing method according to a first embodiment. 5 is a cross-sectional view for explaining the direction of incidence of a deposition material from a cover plate portion to a substrate to be processed. FIG. FIG. 13 is a diagram illustrating a modified example of the deposition source.

Hereinafter, a first embodiment of the method for manufacturing an evaporation source of the present invention, which is used for evaporation (film formation) by vacuum evaporation, will be described with reference to the drawings. In the following, terms indicating directions such as "up" and "down" are based on FIG. 1.

With reference to FIG. 1, the deposition source EV includes a storage box Sb and a heating means Ht. The storage box Sb, which is a component of the deposition source EV, is composed of a box portion 11 filled with a deposition material Em and a cover plate portion 12 detachably attached to the upper end of the box portion 11. The box portion 11 is made of a heat-resistant material such as stainless steel (SUS304, etc.), titanium, tantalum, tungsten, molybdenum, or carbon, and is molded into a rectangular parallelepiped or cylindrical shape with an open top. An inner container 13 that can be freely inserted and removed from the top opening is stored in the box portion 11. The inner container 13 is also made of a heat-resistant material such as stainless steel (SUS304, etc.), titanium, tantalum, tungsten, molybdenum, or carbon, and is molded to have the same contour as the box portion 11. When the inner container 13 is stored in the box portion 11, a predetermined gap is formed between the box portion 11 and the inner container 13. In this case, the lower end of the inner container 13 is provided with legs (not shown) that abut against the bottom surface of the box portion 11, and the inner container 13 is supported by the legs.

A sheathed heater is attached to the inner surface of the box portion 11 as a heating means Ht, so that the inner container 13 can be heated by the sheathed heater. The cover plate portion 12, which is attached to cover the top openings of the box portion 11 and the inner container 13, is made of a silicon substrate having a predetermined plate thickness, and the silicon substrate 12 is formed with a large number of closely spaced through holes 14 as emission portions, each having a fine diameter and with the spacing between adjacent holes as small as possible. Below, a method for manufacturing the cover plate portion 12 as a component of the deposition source EV of the first embodiment will be specifically described with reference to FIG. 2.

As shown in FIG. 2(a), a silicon substrate 12 having a predetermined thickness (e.g., 200 to 800 μm) is prepared, and a mask material layer 2 is formed on one surface of the silicon substrate 12. There are no particular limitations on the mask material layer 2, so long as it functions as a mask to limit the etching range during etching, which will be described later. However, like the silicon substrate 12, a silicon compound layer such as a silicon oxide layer, a silicon nitride layer, or a silicon oxynitride layer having a relatively high thermal conductivity can be used. To form the mask material layer 2, a known vacuum film formation process such as a CVD method or a reactive sputtering method can be used, and the CVD method is particularly advantageous because of its high film formation speed. Note that the film formation conditions can be those known in the manufacturing process of semiconductor devices, and therefore a detailed description will be omitted here.

When the silicon compound film is used as the mask material layer 2, the mask material layer 2 can also be a component of the emission section, so the film thickness of the mask material layer 2 is set according to the length of the emission section to be formed, and can be set in the range of 50 to 500 μm, for example. Then, resist 3 is applied to one side of the mask material layer 2. For example, a known spin coating method can be used to apply the resist 3. As with the above, the material and application conditions of the resist 3 can be known, so a detailed explanation is omitted here.

Next, as shown in FIG. 2(b), the resist 3 is patterned by lithography (technology) according to the pattern of the emission portion to be formed, to form a resist pattern 3a. As the lithography, known photolithography or EB lithography can be used. As the exposure device, exposure conditions, and development conditions after exposure, known ones can be used as above, so further explanation is omitted. Then, the mask material layer 2 is etched using the resist pattern 3a as a mask, so that a plurality of openings 2a communicating with the through holes 14 are formed in the mask material layer 2 (first step). For etching the mask material layer 2, dry etching using an etching gas appropriately selected according to the material of the mask material layer 2 or wet etching using an etching solution can be used. In this case, dry etching is advantageous when the film thickness of the mask material layer 2 is increased, since anisotropic etching with good shape control is possible depending on the dry etching. In addition, a known reactive etching device is used for dry etching, and when the mask material layer 2 is silicon oxide, at least one selected from _CF4 gas, _CHF3 gas, and _COF2 gas is used as the etching gas. Then, as shown in FIG. 2(c), the resist pattern 3a is removed. A known ashing process or chemical treatment can be used to remove the resist pattern 3a. Note that since known ashing devices, ashing conditions, and chemicals can be used, detailed explanations are omitted here.

Next, as shown in FIG. 2(d), the silicon substrate 12 is etched using the mask material layer 2 with the openings 2a formed therein as a mask. This forms a plurality of through holes 14 in the silicon substrate 12 according to the resist pattern 3a (second step). The diameter of the through holes 14 can be set in the range of 1 to 100 μm, for example. The silicon substrate 12 can be etched by dry etching using an appropriately selected etching gas or wet etching using an etching solution. As above, it is advantageous to use dry etching.

In addition , a so-called hard mask of a predetermined thickness can also be used as the mask material layer 2. The hard mask can be adhered to one surface of the silicon substrate 12, and after the through holes are formed in the silicon substrate 12, the hard mask can be used as it is.

According to the above, for example, when the deposition source EV is placed in the vacuum chamber of the vacuum deposition device, each emission section composed of the through hole 14 formed by etching is formed on the cover plate section 12 of the storage box Sb facing the substrate to be processed. Therefore, by simply appropriately selecting the pattern of the openings 2a formed in the mask material layer 2, a large number of emission sections having a fine diameter and with the distance between adjacent ones as small as possible can be densely formed on the cover plate section 12 of the storage box Sb. Moreover, since the mask material layer 2 is left as it is after the second process, and the emission section is composed of the openings 2a formed in the mask material layer 2 and the through hole 14 communicating therewith, the emission section can be lengthened by the thickness of the mask material layer 2, which is advantageous in improving the linearity of the deposition material Em emitted from each emission section.

Next, referring to FIG. 3, a method for manufacturing the cover plate portion as a component of the deposition source of the second embodiment will be specifically described. As shown in FIG. 3(a), two silicon substrates 120 having a predetermined thickness and the same outline are prepared, and after a hydrophilic treatment, the two silicon substrates 120, 120 are bonded together. The two bonded silicon substrates 120, 120 are then stored in a vacuum heating furnace and heated to a predetermined temperature to be bonded via a silicon oxide layer (not shown).

Next, as shown in Fig. 3(b), a resist pattern 3a is formed on one surface of the upper silicon substrate (second silicon substrate) 120 in the figure, in the same manner as in the first embodiment. Then, as shown in Fig. 3(c), the two silicon substrates 120, 120 are successively etched using the resist pattern 3a as a mask, thereby forming through holes ₁₄₁ , ₁₄₂ that communicate between the two silicon substrates 120, 120. The etching method may be the same as in the first embodiment. Finally, as shown in Fig. 3(d), the resist pattern 3a is removed by the same method as in the first embodiment.

According to the above, by bonding two silicon substrates 120, 120 and forming an emission section with through holes 14 ₁ , 14 ₂ communicating with both silicon substrates 120, 120, the linearity of the deposition material Em emitted from each emission section can be improved, which is advantageous. The number of silicon substrates 120 to be bonded is not limited to two, and three or more may be bonded. In addition, a step of polishing the second silicon substrate 120 to a predetermined plate thickness can be further included depending on the length of each emission section to be formed. In addition, the bonding method is not limited to the above, and for example, a known method for bonding SOI substrates can be used.

The deposition source EV manufactured as described above can be applied to a vacuum deposition apparatus as follows. That is, as shown in FIG. 4, the vacuum deposition apparatus Dm equipped with the deposition source EV includes a vacuum chamber Cv capable of evacuating, and a rotating body 4 is provided at the top of the vacuum chamber Cv to hold the substrate Sw to be processed with its deposition surface facing downward. Although not specifically shown or described, an electrode for electrostatic chuck is embedded in the rotating body 4, and the substrate Sw to be processed can be attracted and held by electrostatic force when a voltage is applied to the electrode. In addition, a rotating shaft 41a that extends through the upper wall of the vacuum chamber Cv and rotates around the central axis Cl by a motor 41 is connected to the rotating body 4. Note that, when depositing on the substrate Sw to be processed, a mask plate Mp is attached to the deposition surface to limit the deposition range. The deposition source EV is provided at the bottom of the vacuum chamber Cv facing the substrate Sw to be processed. The deposition source EV is installed offset radially (left side in FIG. 4) from the central axis Cl. The offset amount d is set appropriately taking into consideration the diameter of the cover plate portion 12 and the substrate Sw to be processed, the distance L between the deposition source EV and the substrate Sw to be processed, etc.

When the organic light-emitting layer Le is deposited in each deposition region Rd in which the deposition surface of the substrate Sw is partitioned by the PDL (Pd) using the vacuum deposition device Dm, the deposition material Em filled in the inner container 13 is heated by the heating means Ht in the vacuum chamber Vc in a vacuum atmosphere. Then, the deposition material Em vaporized or sublimated in the storage box is discharged toward the substrate Sw according to a predetermined cosine law through each through hole 14 and each opening 2a (see FIG. 5). At this time, as shown by the arrows in FIG. 5, the deposition material Em is incident on the deposition region Rd from multiple emission parts, so that the organic light-emitting layer Le can be deposited with a uniform film thickness. Moreover, since the number of emission parts that incident the deposition material Em and the incidence angle do not change much for each deposition region Rd, the film thickness variation of the organic light-emitting layer Le in each deposition region Rd can be suppressed as much as possible. Furthermore, since the silicon substrate constituting the cover plate portion 12 and the silicon compound layer constituting the mask material layer 2 have a relatively high thermal conductivity, they are heated and maintained at a high temperature by heat transfer from the box portion 11. This prevents the deposition material Em from clogging the holes 14 and openings 2a, even if the holes 14 and openings 2a constituting each release portion are formed with a fine diameter.

Although the embodiment of the present invention has been described above, various modifications are possible without departing from the scope of the technical concept of the present invention. In the above embodiment, the through holes 14 as the discharge parts are formed with the same hole diameter and pitch over the entire surface of the cover plate part 12, but as shown in FIG. 6, the cover plate part 12 may be divided into a plurality of areas R1 and R2 (two in this modification), and the discharge parts 14a and 14b may be formed with different patterns (different hole diameters or pitches) in each area R1 and R2, so that the discharge parts 14a and 14b can be used differently depending on the type of substrate Sw to be processed. In this case, a shutter plate 5 is interposed between the cover plate part 12 and the substrate Sw to be processed, and the piston rod 51a connected to the shutter plate 5 is driven by the actuator 51 to move the shutter plate 5 in one direction (left and right direction in FIG. 6), thereby blocking the discharge parts 14b of the unused area R2. Note that in FIG. 6, the discharge parts 14a and 14b are illustrated large for easy understanding. The number of areas may be three or more, and the shutter mechanism, including the shutter plate, may be configured according to the number and shape of the areas.

In the above embodiment, the substrate Sw held by the rotor 4 is rotated, but the present invention is not limited to this and can also be applied to a case where the substrate Sw is transported in one direction. In this case, it is preferable to configure a substantially linear deposition source by arranging multiple storage boxes Sb side by side.

EV... deposition source, Sb... storage box, Em... deposition material, Sw... substrate to be processed, 11... box portion, 12... cover plate portion (upper surface of storage box), silicon substrate, 120... silicon substrate, ₁₄ , 141, ₁₄₂ , 14a, 14b... through hole (emission portion), 120... silicon substrate, 2... mask, mask material layer, 2a... opening (emission portion), 3... resist, 3a... resist pattern (patterned resist), R1, R2... area.

Claims (5)

1. A method for manufacturing a deposition source, comprising: forming a plurality of emission portions in a predetermined pattern on an upper surface of a container filled with a deposition material, the emission portions allowing passage of a deposition material vaporized or sublimated by heating the container;
The method further includes a first step of providing a mask on the upper surface of the container box to limit the etching range, the etching range being defined as each of the emission portions formed in a predetermined pattern, and a second step of etching the etching range of the container box through the mask to form a plurality of through holes reaching a space within the container box,
The first step includes a step of forming a mask material layer on the upper surface of the container box, a step of applying a resist to the surface of the mask material layer, patterning the resist by lithography, and a step of forming an opening communicating with the upper surface of the container box in the mask material layer by etching using the patterned resist as a mask;
A method for manufacturing an evaporation source, comprising the steps of : removing the resist pattern after the second step; and leaving the mask material layer on the upper surface of the container box without removing the mask material layer. 2. The method for manufacturing an evaporation source according to claim 1, wherein the storage box is composed of a box portion for storing the evaporation material and a cover plate portion removably attached to an upper end of the box portion,
The method for manufacturing an evaporation source, wherein the cover plate portion is a silicon substrate. 1. A method for manufacturing a deposition source, comprising: forming a plurality of emission portions in a predetermined pattern on an upper surface of a container filled with a deposition material, the emission portions allowing passage of a deposition material vaporized or sublimated by heating the container;
The method further includes a first step of providing a mask on the upper surface of the container box to limit the etching range, the etching range being defined as each of the emission portions formed in a predetermined pattern, and a second step of etching the etching range of the container box through the mask to form a plurality of through holes reaching a space within the container box,
The storage box is composed of a box portion for storing a deposition material and a cover plate portion removably attached to an upper end of the box portion, the cover plate portion being a silicon substrate,
A method for manufacturing an evaporation source, comprising the steps of: forming a mask material layer on an upper surface of a silicon substrate; applying a resist onto the mask material layer, patterning the resist by lithography, and using the patterned resist as a mask, forming an opening leading to the upper surface of the silicon substrate by etching. 1. A method for manufacturing a deposition source, comprising: forming a plurality of emission portions in a predetermined pattern on an upper surface of a container filled with a deposition material, the emission portions allowing passage of a deposition material vaporized or sublimated by heating the container;
The method further includes a first step of providing a mask on the upper surface of the container box to limit the etching range, the etching range being defined as each of the emission portions formed in a predetermined pattern, and a second step of etching the etching range of the container box through the mask to form a plurality of through holes reaching a space within the container box,
The storage box is composed of a box portion for storing a deposition material and a cover plate portion removably attached to an upper end of the box portion, the cover plate portion being a silicon substrate,
a first step including a step of using a silicon substrate as a first silicon substrate, bonding a second silicon substrate to an upper surface of the first silicon substrate, and heating the bonded silicon substrates at a predetermined temperature to bond them together; and a step of applying a resist onto the second silicon substrate and patterning the resist by lithography . A second step including a step of using the patterned resist as a mask to form through holes that communicate with each other in a vertical direction by etching. The method for manufacturing a deposition source according to any one of claims 1 to 4, characterized in that the upper surface of the container box is divided into a plurality of areas, and the emission parts are provided in different patterns in each of these divided areas.

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