Method for manufacturing an evaporation source

Abstract

To provide a method for manufacturing a vapor deposition source, capable of densely forming a lot of discharge parts on a surface facing a substrate to be processed to each other.SOLUTION: A method for manufacturing a vapor deposition source EV comprises: a step of forming a plurality of discharge parts allowing the passage of the vapor deposition material evaporated or sublimated by heating a storage box Sb for charging a vapor deposition material Em with a predetermined pattern in the lid plate part 12 of the storage box; a first step of providing a mask 2 using each discharge part formed with the predetermined pattern as an etching range and restricting the etching range in the lid plate part of the storage box; and a second step of etching the etching range of the storage box through the mask to form a plurality of through-holes 14 reaching a space in the storage box.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a vapor deposition source.

Background Art

[0002] In recent years, devices capable of experiencing virtual worlds such as AR, VR, or MR have been actively developed. For monitors that reproduce video content in such devices, organic EL displays having advantages such as a wide viewing angle have attracted attention. At this time, for organic EL displays, a fineness of, for example, 2000 ppi or more is required. As one of the manufacturing methods for such organic EL displays, it is known to vapor-deposit an organic light-emitting layer that emits red (R), green (G), and blue (B) fluorescence on the surface of a substrate to be processed with high fineness by dividing them separately. The substrate to be processed is usually partitioned into minute vapor deposition regions by a PDL (generally, the size of a unit element composed of each organic light-emitting layer of RGB is 1 inch square, and the so-called pixel pitch is about 12 μm). By vapor-depositing each organic light-emitting layer on the partitioned vapor deposition regions, bleeding of RGB within each element is suppressed, and uneven brightness and color mixing are suppressed.

[0003] The vacuum deposition apparatus that can be used for the above applications is known, for example, from Patent Document 1. This apparatus includes a vacuum chamber, and a plurality of evaporation sources are provided inside the vacuum chamber. As the evaporation source, it has a housing box that is longitudinally long in one direction and filled with a solid evaporation substance (organic material) corresponding to fluorescence. On the upper surface of the housing box facing the substrate to be processed, a plurality of cylindrical discharge nozzles (discharge portions) that protrude outward are arranged in a row at intervals (so-called linear source). When the evaporation substance in the housing box is heated by heating means in a vacuum chamber with a vacuum atmosphere, the sublimated or vaporized evaporation substance is discharged from the discharge nozzles according to a predetermined cosine law. When using such an evaporation source to deposit an organic light-emitting layer in a partitioned evaporation region, if the distance between the discharge nozzles is large, the number and incident angle of the discharge nozzles for injecting the evaporation substance will change for each evaporation region. For this reason, there is a problem that the film thickness of the organic light-emitting layer in each evaporation region is likely to vary, and in this case, the performance of each element will not be stable. In such a case, a large number of discharge nozzles may be provided close to each other on the upper surface of the housing box. However, considering the installation space and strength, there is a limit to the number of discharge nozzles having a predetermined diameter.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above points, an object of the present invention is to provide a method for manufacturing an evaporation source in which a large number of discharge portions can be formed densely on the surface facing the substrate to be processed.

Means for Solving the Problems

[0006] In order to solve the above problems, a method for manufacturing a vapor deposition source of the present invention includes a step of forming a plurality of discharge portions that allow the passage of a vapor deposition material vaporized or sublimated by heating the storage box on the upper surface of the storage box filled with the vapor deposition material in a predetermined pattern. The method further includes a first step of using each discharge portion formed in the predetermined pattern as an etching range and providing a mask on the upper surface of the storage box to limit the 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 inside the storage box. Premise It is like this.

[0007] According to the present invention, for example, when disposed in a vacuum chamber of a vacuum vapor deposition apparatus, each discharge portion is constituted by a through hole formed by etching on the upper surface of the storage box facing the substrate as the film formation target object. Therefore, by simply appropriately selecting the mask pattern, a large number of discharge portions having a fine diameter and having the interval between adjacent ones as small as possible can be densely formed on the upper surface of the storage box. Here, the etching in the second step includes not only dry etching but also wet etching. Also, in the present invention In , the first step includes forming a mask material layer on the upper surface of the storage box, applying a resist on the surface of the mask material layer, patterning it by lithography, and using this patterned resist as a mask to form an opening leading to the upper surface of the storage box in the mask material layer by etching, After the second step, while removing the resist pattern and leaving the mask material layer It is characterized in that it is left on the upper surface of the storage box without being removed. Thereby, since the discharge portion can be lengthened by the thickness of the mask, the straightness of the vapor deposition material discharged from the discharge portion can be improved, which is advantageous. material layer

[0008] In the present invention, when the storage box is composed of a box portion filled with the vapor deposition material and a cover plate portion detachably attached to the upper end of the box portion, it is preferable that the cover plate portion is a silicon substrate. The first step includes a step of forming a mask material layer on the upper surface of the silicon substrate, applying a resist on the mask material layer, patterning it by lithography, and using the patterned resist as a mask to perform etching on the upper surface of the silicon substrateIt may include a step of forming an opening communicating with the through hole. According to this, a mask material generally used in the manufacturing process of a so-called semiconductor device, an etching solution, or an etching gas can be used, which is advantageous. Moreover, when heating the box part of the storage box to vaporize or sublime the deposited substance filled therein, since the silicon substrate has a relatively high thermal conductivity, it is heated to a high temperature and held by heat transfer from the box part. Thereby, even if each through hole as a discharge part is formed with a fine diameter, it is possible to prevent as much as possible the deposited substance from clogging there. 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 preferably used.

[0009] On the other hand, in the present invention, the first step includes a step of using the silicon substrate as a first silicon substrate, bonding a second silicon substrate to the upper surface of the first silicon substrate, and heating and bonding these two bonded silicon substrates at a predetermined temperature, and a step of applying a resist on the second silicon substrate and patterning it by lithography. The second step can include a step of forming through holes communicating with each other in the vertical direction by etching using the patterned resist as a mask. According to this, since each discharge part is constituted by through holes communicating the first silicon substrate and the second silicon substrate, the discharge part can be lengthened by the thickness of each silicon substrate, which is advantageous. In this case, a plurality of silicon substrates may be further bonded.

[0010] Further, in the present invention, it is preferable that the upper surface of the storage box is partitioned into a plurality of areas, and the discharge parts are provided in these partitioned areas with different patterns. According to this, a vapor deposition source capable of selectively using the discharge parts according to the type of the substrate to be processed can be manufactured. In this case, the unused discharge parts may be configured to be shielded by, for example, a shutter mechanism.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0012] Hereinafter, with reference to the drawings, a first embodiment of a method for manufacturing an evaporation source of the present invention used for evaporation (film formation) by a vacuum evaporation method will be described. In the following, terms indicating directions such as "up" and "down" are based on FIG. 1.

[0013] Referring to FIG. 1, the evaporation source EV includes a storage box Sb and a heating means Ht. The storage box Sb as a component of the evaporation source EV is composed of a box portion 11 filled with an evaporation substance 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 formed in a rectangular parallelepiped shape or a cylindrical shape with an open upper surface. Inside the box portion 11, an inner container 13 that can freely enter and exit through the upper surface opening is stored. 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 formed 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, a leg piece (not shown) that abuts against the lower surface of the box portion 11 is provided at the lower end of the inner container 13, and the inner container 13 is supported by the leg piece.

[0014] A sheath heater as a heating means Ht is attached to the inner surface of the box portion 11 so that the inner container 13 can be heated by the sheath heater. The cover plate portion 12 attached to close the upper surface openings of the box portion 11 and the inner container 13 is composed of a silicon substrate having a predetermined plate thickness. On the silicon substrate 12, a large number of through holes 14 as discharge portions having a fine diameter and having the smallest possible interval between adjacent ones are densely formed. Hereinafter, with reference to FIG. 2, a manufacturing method of the cover plate portion 12 as a component of the vapor deposition source EV according to the first embodiment will be specifically described.

[0015] As shown in FIG. 2(a), a single silicon substrate 12 having a predetermined plate thickness (for example, 200 to 800 μm) is prepared, and a mask material layer 2 is formed on one surface of the silicon substrate 12. The mask material layer 2 is not particularly limited as long as it functions as a mask for restricting the etching range during the etching described later. However, similar to 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. For the formation of the mask material layer 2, known vacuum film formation processes such as CVD method and reactive sputtering method can be used. In particular, the CVD method is advantageous because of its high film formation speed. Note that, as the film formation conditions, for example, those known in the manufacturing process of semiconductor devices can be used, and thus detailed description is omitted here.

[0016] Here, when the silicon compound film is used as the mask material layer 2, since the mask material layer 2 can also be a component of the discharge portion, the film thickness of the mask material layer 2 is set according to the length of the discharge portion to be formed, and can be set, for example, in the range of 50 to 500 μm. Then, a resist 3 is applied to one surface of the mask material layer 2. For the application of the resist 3, for example, a known spin coating method can be used. Note that, as the material and application conditions of the resist 3, those known as above can be used, and thus detailed description is omitted here.

[0017] Next, as shown in Fig. 2(b), the resist 3 is patterned according to the pattern of the emission part to be formed by lithography (technology), thereby forming a resist pattern 3a. As the lithography, known photolithography or EB lithography can be used. Note that, as the exposure apparatus, exposure conditions, and development conditions after exposure, known ones can be used as in the above, and thus further explanation is omitted. Then, by etching the mask material layer 2 using the resist pattern 3a as a mask, a plurality of openings 2a communicating with the through holes 14 are formed in the mask material layer 2 (first step). For the etching of 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, depending on the dry etching, since anisotropic etching is possible with good shape controllability, it is advantageous when the film thickness of the mask material layer 2 is increased. Also, for dry etching, a known reactive etching apparatus is used. When the mask material layer 2 is made of 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. For the removal of the resist pattern 3a, known ashing treatment or chemical solution treatment can be used. Note that, as the ashing apparatus, ashing conditions, and chemical solution, known ones can be used, and thus detailed explanation is omitted here.

[0018] Next, as shown in Fig. 2(d), the silicon substrate 12 is etched using the mask material layer 2 having the openings 2a formed therein as a mask. Thereby, a plurality of through holes 14 corresponding to the resist pattern 3a are formed in the silicon substrate 12 (second step). The pore diameter of the through holes 14 can be set, for example, in the range of 1 to 100 μm. For the etching of the silicon substrate 12, dry etching using an appropriately selected etching gas or wet etching using an etching solution can be used. As in the above, it is advantageous to use dry etching.

[0019] Note 、maAs the mask material layer 2, a so-called hard mask with a predetermined plate thickness can also be used. The hard mask is adhered to one surface of the silicon substrate 12, and after the formation of the through holes in the silicon substrate 12, the hard mask can also be used as it is.

[0020] According to the above, for example, when the evaporation source EV is arranged in the vacuum chamber of the vacuum evaporation apparatus, each discharge part composed of the through holes 14 formed by etching is formed in the cover plate part 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 discharge parts having a fine diameter and having the intervals between adjacent ones as small as possible can be densely formed in the cover plate part 12 of the storage box Sb. Moreover, since the mask material layer 2 is left as it is after the second step, and the discharge part is constituted by the opening 2a formed in the mask material layer 2 and the through hole 14 communicating therewith, the discharge part can be lengthened by only the thickness of the mask material layer 2. Therefore, the straightness of the deposited material Em discharged from each discharge part can be improved, which is advantageous.

[0021] Next, with reference to FIG. 3, a method for manufacturing the cover plate part as a component of the evaporation source according to the second embodiment will be specifically described. As shown in FIG. 3(a), two silicon substrates 120 having a predetermined plate thickness and having the same contour are prepared. After being subjected to a hydrophilic treatment, the two silicon substrates 120, 120 are bonded together. Then, after the two bonded silicon substrates 120, 120 are stored in a vacuum heating furnace, they are heated to a predetermined temperature and bonded through a silicon oxide layer (not shown).

[0022] Next, as shown in FIG. 3(b), in the same manner as in the first embodiment, a resist pattern 3a is formed on one surface of the upper silicon substrate (second silicon substrate) 120 in the figure. Then, as shown in FIG. 3(c), by continuously etching both silicon substrates 120, 120 using the resist pattern 3a as a mask, through holes 141, 142 communicating both silicon substrates 120, 120 are formed. As the etching method, the same method as in the first embodiment can be used. Finally, as shown in FIG. 3(d), the resist pattern 3a is removed in the same manner as in the first embodiment.

[0023] According to the above, since two silicon substrates 120, 120 are joined and the discharge portions are configured by the through holes 141, 142 that communicate the two silicon substrates 120, 120, the straightness of the deposited material Em discharged from each discharge portion can be improved, which is advantageous. Note that the number of silicon substrates 120 to be joined is not limited to two, and three or more substrates may be joined. Further, according to the length of each discharge portion to be formed, a step of polishing the second silicon substrate 120 to a predetermined plate thickness can be further included. Also, the joining method is not limited to the above, and for example, a known method of joining an SOI substrate can be used.

[0024] The vapor deposition source EV manufactured as described above can be applied to a vacuum vapor deposition apparatus as follows. That is, as shown in FIG. 4, a vacuum vapor deposition apparatus Dm including the vapor deposition source EV includes a vacuum chamber Cv that can be evacuated. Above the vacuum chamber Cv, a rotator 4 that holds the substrate to be processed Sw with its vapor deposition surface facing downward is provided. Although not particularly shown and described, an electrode for an electrostatic chuck is embedded in the rotator 4, and the substrate to be processed Sw can be adsorbed and held by the electrostatic force when a voltage is applied to the electrode. Further, the rotator 4 has a rotary shaft 41a that extends through the upper wall of the vacuum chamber Cv and rotates around the central axis Cl by a motor 41. Note that during vapor deposition on the substrate to be processed Sw, a mask plate Mp is attached to the vapor deposition surface so that the vapor deposition range is limited. And, the above-described vapor deposition source EV is provided below the vacuum chamber Cv so as to face the substrate to be processed Sw. The vapor deposition source EV is installed offset in the radial direction (left side in FIG. 4) from the central axis Cl. The offset amount d is appropriately set in consideration of the diameter of the cover plate portion 12 and the substrate to be processed Sw, the distance L between the vapor deposition source EV and the substrate to be processed Sw, and the like.

[0025] When depositing the organic light-emitting layer Le on each deposition region Rd in which the deposition surface of the substrate Sw to be processed is partitioned by PDL (Pd) by the above-described vacuum deposition apparatus 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 to be processed in accordance with a predetermined cosine law through each through hole 14 and each opening 2a (see FIG. 5). At this time, as indicated by the arrows in FIG. 5, since the deposition material Em enters the deposition region Rd from a plurality of discharge portions, the organic light-emitting layer Le can be deposited with a uniform film thickness. Moreover, since the number and the incident angle of the discharge portions for making the deposition material Em incident do not vary so much for each deposition region Rd, the variation in the film thickness of the organic light-emitting layer Le in each deposition region Rd can be suppressed as much as possible. Further, since the silicon substrate constituting the cover plate portion 12 and the silicon compound layer constituting the mask material layer 2 have relatively high thermal conductivities, they are heated to a high temperature and held by heat transfer from the box portion 11. Thereby, even if the through holes 14 and the openings 2a constituting each discharge portion are formed with a fine diameter, it is possible to prevent as much as possible the deposition material Em from clogging the through holes 14 and the openings 2a.

[0026] The embodiments of the present invention have been described above. However, various modifications are possible without departing from the scope of the technical idea of the present invention. In the above embodiment, the through-holes 14 as the discharge portions are formed with the same hole diameter and pitch over the entire surface of the cover plate portion 12. However, as shown in FIG. 6, the cover plate portion 12 is divided into a plurality of (two in this modified example) areas R1 and R2, and the discharge portions 14a and 14b are formed in each area R1 and R2 with different patterns (different hole diameters or pitches). For example, the discharge portions 14a and 14b can be selectively used according to the type of the substrate Sw to be processed. In this case, a shutter plate 5 is interposed between the cover plate portion 12 and the substrate Sw to be processed, and the piston rod 51a connected to the shutter plate 5 is driven by an actuator 51 to move the shutter plate 5 in one direction (the left-right direction in FIG. 6), so that the discharge portion 14b in the unused area R2 can be shielded. In FIG. 6, the discharge portions 14a and 14b are shown enlarged for easy understanding. Also, the number of areas may be three or more, and a shutter mechanism including a shutter plate may be configured according to the number and shape of the areas.

[0027] In the above embodiment, the case where the substrate Sw to be processed held by the rotating body 4 is rotated has been described as an example. However, the present invention is not limited to this, and the present invention can also be applied to the case where the substrate Sw to be processed is conveyed in one direction. In this case, it is preferable to configure a substantially linear evaporation source by arranging a plurality of storage boxes Sb in parallel.

Explanation of Reference Numerals

[0028] EV... Evaporation source, Sb... Storage box, Em... Evaporation substance, Sw... Substrate to be processed, 11... Box portion, 12... Cover plate portion (upper surface of the storage box), silicon substrate, 120... Silicon substrate, 14, 141, 142, 14a, 14b... Through-holes (discharge portions), 120... Silicon substrate, 2... Mask, mask material layer, 2a... Opening (discharge portion), 3... Resist, 3a... Resist pattern (patterned resist), R1, R2... Areas.

Claims

1. A method for manufacturing an evaporation source, comprising a step of forming, in a predetermined pattern, a plurality of discharge portions on an upper surface of a storage box filled with an evaporation material, the discharge portions allowing passage of the evaporation material vaporized or sublimated by heating of the storage box. Further including a first step of providing, on the upper surface of the storage box, a mask for restricting an etching range, with each discharge portion formed in the predetermined pattern being an etching range, and a second step of etching through the mask the etching range of the storage box to form a plurality of through holes reaching the space inside the storage box. The first step includes a step of forming a mask material layer on the upper surface of the storage box, applying a resist on the surface of the mask material layer, patterning it by lithography, and using the patterned resist as a mask to form, by etching, an opening in the mask material layer that communicates with the upper surface of the storage box. A method for manufacturing an evaporation source, 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 storage box without being removed.

2. A method for manufacturing an evaporation source according to Claim 1, wherein in the case where the storage box is composed of a box portion for storing the evaporation material and a lid plate portion detachably attached to the upper end of the box portion, The method for manufacturing an evaporation source, characterized in that the lid plate portion is a silicon substrate.

3. A method for manufacturing an evaporation source, comprising a step of forming, in a predetermined pattern, a plurality of discharge portions on an upper surface of a storage box filled with an evaporation material, the discharge portions allowing passage of the evaporation material vaporized or sublimated by heating of the storage box. Further including a first step of providing, on the upper surface of the storage box, a mask for restricting an etching range, with each discharge portion formed in the predetermined pattern being an etching range, and a second step of etching through the mask the etching range of the storage box to form a plurality of through holes reaching the space inside the storage box. The storage box is composed of a box portion for storing the evaporation material and a lid plate portion detachably attached to the upper end of the box portion, and the lid plate portion is a silicon substrate. The first step includes a step of forming a mask material layer on the upper surface of a silicon substrate, applying a resist on the mask material layer, patterning it by lithography, and using this patterned resist as a mask to form an opening leading to the upper surface of the silicon substrate by etching. A method for manufacturing an evaporation source, characterized in that it comprises the steps.

4. A method for manufacturing an evaporation source, including a step of forming, in a predetermined pattern, a plurality of discharge portions that allow the passage of an evaporation substance vaporized or sublimated by heating the storage box on the upper surface of the storage box for filling the evaporation substance. Further including a first step of using each discharge portion formed in a predetermined pattern as an etching range and providing a mask for restricting the etching range on the upper surface of the storage box, 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 inside the storage box. The storage box is composed of a box portion for storing the evaporation substance and a cover plate portion detachably attached to the upper end of the box portion. The cover plate portion is used as a silicon substrate. The first step includes using the silicon substrate as a first silicon substrate, bonding a second silicon substrate to the upper surface of the first silicon substrate, heating and bonding these two bonded silicon substrates at a predetermined temperature, and applying a resist on the second silicon substrate and patterning it by lithography. The second step includes using the patterned resist as a mask and forming through holes that communicate with each other in the vertical direction by etching. A method for manufacturing an evaporation source, characterized in that it comprises the steps.

5. The method for manufacturing an evaporation source according to any one of claims 1 to 4, characterized in that the upper surface of the storage box is partitioned into a plurality of areas, and the discharge portions are provided in different patterns in these partitioned areas.

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