Evaporation source for vacuum deposition apparatus
The vacuum deposition source uses a shutter with annular damping plates to attenuate deposition material reflections, addressing mixing issues and simplifying the mechanism, thereby enhancing film quality and reducing costs.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- ULVAC INC
- Filing Date
- 2022-05-26
- Publication Date
- 2026-06-01
AI Technical Summary
Existing vacuum deposition apparatuses face issues with deposition material mixing due to reflection and adhesion, leading to changes in film characteristics, and require complex mechanisms for shutter movement, increasing costs and complexity.
A vacuum deposition source with a shutter having an annular first damping plate and a second damping plate around the crucible, forming a space between them to attenuate deposition material reflections, reducing its arrival on the substrate by multiple reflections and controlled energy loss.
The solution effectively suppresses deposition material reaching the substrate, minimizing film characteristic changes and simplifies the shutter mechanism, reducing costs and complexity.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an evaporation source for a vacuum evaporation apparatus that is disposed in a vacuum chamber and evaporates onto a deposition target.
Background Art
[0002] For example, in the manufacturing process of an organic EL element, there is a process of continuously forming (laminating) an organic material or a metal material (evaporation material) on one surface (film formation surface) of a glass substrate as a deposition target. For such a process, for example, an inline vacuum evaporation apparatus is used (see, for example, Patent Document 1). This apparatus includes a vacuum chamber to which a vacuum pump is connected. In the vacuum chamber, a plurality of evaporation sources are arranged in a row at a predetermined interval in one direction, and substrate transfer means for transferring a substrate along the arrangement direction of each evaporation source is provided. The evaporation source includes a crucible that accommodates an evaporation material and has a discharge opening formed on its upper surface, heating means for heating the evaporation material in the crucible, and a shutter that selectively blocks the scattering path of the evaporation material vaporized or sublimated by heating the evaporation material in the crucible and discharged from the discharge opening to the film formation surface of the substrate.
[0003] The shutter has a shutter body and a drive source that rotates the shutter body between a shielding position that is spaced above the discharge opening and blocks the scattering path and an open position that is separated from above the discharge opening and opens the discharge opening. As the shutter body, generally, one having an inverted dish-shaped contour having a base plate portion (base end portion) and a skirt portion hanging from the outer peripheral edge portion of the lower surface of the base plate portion is used. Then, while the substrate is continuously (or intermittently) transferred from the upstream side to the downstream side by the substrate transfer means, when the substrate passes through a position facing any one of the evaporation sources, only the shutter body is moved to the open position, and the evaporation material discharged from the discharge opening is attached and deposited on the film formation surface of the substrate, thereby forming a laminated film.
[0004] However, it has been found that with the shutter configuration described above, when depositing a film on the substrate surface while passing it to a position opposite one deposition source (crucible), vaporized or sublimated deposition material from other deposition sources (crucibles) may adhere to (become mixed in). This is thought to be because some of the deposition material (atoms and molecules) emitted from the release opening at the shielding position is reflected off the inner surface of the shutter body, and this reflected material bounces out from inside the shutter body, where it is further reflected off the surface of components such as anti-adhesion plates arranged around the crucible and heads towards the film surface. The mixing of deposition material can cause problems such as changes in film characteristics (device performance), so it is necessary to suppress this as much as possible. In such cases, for example, it is conceivable to configure the pivot axis that rotates the shutter body to move up and down freely, rotate the shutter body to the shielding position, and then lower the shutter body so that its inner surface comes into contact with the crucible and closes the inside of the crucible. In this configuration, in addition to the mechanism for rotating the shutter's pivot axis, a mechanism for vertical movement is required. This not only increases the number of parts and complicates the device, but also leads to increased costs. [Prior art documents] [Patent Documents]
[0005] [Patent Document 1] Patent No. 6179908 [Overview of the project] [Problems that the invention aims to solve]
[0006] In view of the above, the object of the present invention is to provide a deposition source for a vacuum deposition apparatus having a structure that can suppress as much as possible the reach of the deposition material discharged from the discharge opening to the object to be deposited at the shielded position. [Means for solving the problem]
[0007] To solve the above problems, the present invention provides a deposition source for a vacuum deposition apparatus that is arranged in a vacuum chamber for deposition on an object to be deposited, comprising: a crucible that contains a deposition material and has an outlet opening on its upper surface; a heating means for heating the deposition material in the crucible; and a shutter that selectively blocks the scattering path of the deposition material discharged from the outlet opening, wherein the shutter comprises a shutter body having a base end and a skirt portion hanging down from the base end, an annular first damping plate portion extending in a circumferential direction perpendicular to the vertical direction is provided at the lower end of the skirt portion, and a second damping plate portion is arranged around the crucible with an opening facing the upper end of the crucible, and forms a circumferential space between itself and the first damping plate portion.
[0008] According to this, when the deposition material inside the crucible is heated, it vaporizes or sublimes, and a portion of the deposition material (atoms and molecules) released from the release opening is reflected by the inner surface of the shutter body in the shielding position. When this reflected deposition material bounces out of the shutter body, it always enters the space between the first and second damping plates at a predetermined angle of inclination in the vertical direction and passes through that space. At this time, the energy of the deposition material is attenuated by the multiple reflections of the deposition material by the first and second damping plates, and combined with the fact that the end of the space (exit) faces in a direction perpendicular to the substrate, the amount of deposition material heading towards the substrate is reduced to begin with, thereby suppressing the arrival of the deposition material on the object to be deposited as much as possible. In this case, the mechanism for moving the shutter body up and down to close the inside of the crucible in the shielding position becomes unnecessary. In this invention, the length (vertical height) of the skirt portion may be set to be long so that the vapor-deposited material is reflected multiple times and attenuated on the inner surface of the shutter body, and the inner edge of the first attenuation plate portion may be set to extend further inward than the skirt portion.
[0009] In the present invention, a configuration may be adopted in which a protrusion is formed on at least one of the first damping plate portion and the second damping plate portion, thereby creating a labyrinth space. This further suppresses the deposition material from splashing out into the vacuum chamber through the space between the first damping plate portion and the second damping plate portion. Furthermore, if the upper surface of the second damping plate portion is set at a height equal to or lower than the upper surface of the crucible, it is advantageous that when the deposition material is discharged from the discharge opening in the open position, the discharged deposition material is less likely to adhere to the surface of the second damping plate. [Brief explanation of the drawing]
[0010] [Figure 1] A schematic cross-sectional view showing an in-line vacuum deposition apparatus equipped with the deposition source of this embodiment. [Figure 2] (a) is a magnified view of the vapor deposition source shown in Figure 1, and (b) is a plan view thereof. [Figure 3] A cross-sectional view showing a magnified portion of the vapor deposition source related to a modified example. [Modes for carrying out the invention]
[0011] The following describes an embodiment of the present invention using a vacuum deposition apparatus as an example, where the material to be deposited is a glass substrate (hereinafter referred to as "substrate Gs"), and the substrate Gs is transported while attached to a carrier Cs, and multiple thin films are deposited on one side (deposition surface) of the substrate Gs by vacuum deposition.
[0012] Referring to Figure 1, the in-line film deposition apparatus Dm includes a vacuum chamber 1 that is elongated in the left-right direction and defines the film deposition chamber 1a. Although not specifically illustrated and described, an exhaust pipe from a vacuum pump is connected to the vacuum chamber 1, allowing it to be evacuated from atmospheric pressure to a predetermined pressure and maintained. The substrate Gs is then attached to the carrier Cs in a load lock chamber (not shown), and in this state, the substrate is transported at a constant speed in one direction (left-right direction in Figure 1) in the space above the vacuum chamber 1 by the substrate transport means Ts. Note that known methods can be used for the carrier Cs and the attachment and removal of the substrate Gs from the carrier Cs, and known substrate transport means Ts, such as those using transport rollers or transport belts, can also be used, so a detailed explanation is omitted here. Below the vacuum chamber 1, multiple deposition sources ES1, ES2, ES3 are arranged in a row at predetermined intervals in the left-right direction (Figure 1 illustrates the case of three sources).
[0013] Referring also to Figure 2, each deposition source ES1, ES2, and ES3 has the same configuration. For example, the first deposition source ES1, located at the upstream end in the transport direction, includes a crucible 2 that contains the deposition material Em and has a circular discharge opening 21 on its upper surface, a heating means 3 for heating the deposition material Em in the crucible 2, and a shutter Sh that selectively blocks the scattering path of the deposition material Em discharged from the discharge opening 21 toward the substrate Gs. The deposition material Em is appropriately selected according to the composition of each thin film to be laminated on the film deposition surface (bottom surface) of the substrate Gs. Furthermore, known resistance heating or induction heating types can be used as the heating means 3.
[0014] The shutter Sh comprises a shutter body 4 made of a metal such as alumina or stainless steel. The shutter body 4 consists of a circular base plate portion 41 as a base end that has a larger contour than the discharge opening 21 and faces the discharge opening 21 directly at the shielding position described later, a skirt portion 42 hanging down from the outer peripheral edge of the lower surface of the base plate portion 41, and an annular first damping plate portion 43 provided at the lower end of the skirt portion 42. The lower end opening of the skirt portion 42 is set to have a larger area than the base plate portion 41, and the inner end edge of the first damping plate portion 43 protrudes inward from the lower end of the skirt portion 42. In this case, the opening area of the first damping plate portion 43 is set to be larger than the discharge opening 21. Furthermore, the lower surface of the first damping plate portion 43 is positioned above the upper surface of the crucible 2, and the length (vertical height) of the skirt portion 42 is appropriately set, as described later, so that the vapor-deposited material Em emitted from the crucible 2 is reflected multiple times on the inner surface of the shutter body 4 (including the portion protruding inward from the first damping plate portion 43).
[0015] Furthermore, the shutter Sh is equipped with a drive source 5 that rotates the shutter body 4. The drive source 5 comprises a motor 51 located outside the vacuum chamber 1, a pivot shaft 52 connected to the motor 51 and protruding into the vacuum chamber, and a pivot arm 53 connected to the upper end of the pivot shaft 52, with the tip of the pivot arm 53 joined to the upper surface of the base plate 41. When the motor 51 rotates the pivot arm 53 around the pivot shaft 52, the shutter body 4 rotates between a shielding position (shown by a solid line in Figure 2(b)) that blocks the scattering path of the deposition material Em emitted from the discharge opening 21 to the substrate Gs, and an open position (shown by a dashed line in Figure 2(b)) that moves away from the top of the discharge opening 21 and opens the discharge opening 21. The pivot shaft 52 and pivot arm 53 are formed with a refrigerant circulation passage 54 that can circulate refrigerant from a chiller unit (not shown), and the shutter body 4 can be cooled by circulating the refrigerant through the refrigerant circulation passage 54.
[0016] Furthermore, within the vacuum chamber 1, there are protective plates 6 arranged around the crucibles 2, each having an opening 61 that faces the upper end of each crucible 2. The protective plates 6 are supported by a support 62 erected within the vacuum chamber 1, and the upper surface of the protective plates 6 is positioned at or below the height of the upper surface of the crucibles 2. This minimizes the adhesion of the deposited material Es to the upper surface of the protective plates 6 or to the lower surface of the protective plates 6 when the deposited material Em is released from the discharge opening 21 in the open position. In this embodiment, the protective plates 6 function as a second damping plate portion, forming a circumferentially extending space 44 between them and the first damping plate portion 43. When depositing multiple thin films continuously on the underside (deposition surface) of a substrate Gs attached to a carrier Cs in a vacuum deposition chamber 1a using vacuum deposition, the heating means 3 of each deposition source ES1, ES2, and ES3 are activated with the shutter body 4 of each shutter Sh in the shielding position to start heating of each deposition material Em. Once the amount of each deposition material Em released from the discharge opening 21 stabilizes, the substrate transfer means Ts transfers the carrier Cs with the substrate Gs attached from right to left in one direction and at a constant speed in Figure 1. In conjunction with this, the first deposition source ES1 rotates the pivot axis 52 of the drive source 5 to move the shutter body 4 to the open position. As a result, the first thin film is deposited on the deposition surface of the substrate Gs as it passes through the space above the deposition source ES1.
[0017] As the first deposition source ES1 passes through the space above it, the first deposition source ES1 rotates the pivot axis 52 of the drive source 5 to move the shutter body 4 to the shielding position, and the adjacent second deposition source ES2 rotates the pivot axis 52 of the drive source 5 to move the shutter body 4 to the open position. As a result, a second thin film is formed on the surface of the first thin film deposited on the substrate Gs while passing through the space above the second deposition source ES2. At this time, the operation of the heating means 3 is not stopped in the first deposition source ES1, and a stable state is maintained in the release amount of the deposition material Em. In this state, the shutter body 4 may be cooled by circulating the refrigerant in the refrigerant circulation passage 54. By repeating the above operations, as shown in Figure 1, a third thin film is deposited on the surface of the second thin film deposited on the substrate Gs while passing through the space above the third deposition source ES3. The third deposition source ES3 rotates the pivot axis 52 of the drive source 5 to move the shutter body 4 to the shielding position, and then the deposited substrate Gs with a multilayer film formed on its deposition surface is collected.
[0018] According to the above embodiment, when the amount of vapor deposition material Em released is kept stable with the shutter body 4 in the shielding position for each vapor deposition source ES1, ES2, and ES3, as shown by the thin line in Figure 2(a), by setting the length (vertical height) of the skirt portion 42 to be long and setting the inner edge of the first damping plate portion 43 to extend further inward than the skirt portion 42, a portion of the vapor deposition material Em (atoms and molecules) released from the release opening 21 is reflected multiple times on the inner surface of the shutter body 4. When this reflected vapor deposition material Em bounces out of the shutter body 4, it always enters the space 44 between the first damping plate portion 43 and the second damping plate portion 6 at a predetermined inclination angle with respect to the vertical direction and passes through the space 44. As the deposition material Em is reflected multiple times in this manner, its energy is attenuated. Combined with the fact that the end of the space (exit 44a) faces a direction perpendicular to the substrate Gs, thus reducing the amount of deposition material Em heading towards the substrate Gs, the arrival of the deposition material Es on the substrate Gs can be suppressed as much as possible.
[0019] Although embodiments of the present invention have been described above, various modifications are possible as long as they do not deviate from the technical concept of the present invention. In the above embodiments, an example was given in which the second damping plate portion 6 is also used as an anti-adhesion plate, but the invention is not limited to this, and the second damping plate portion 6 can be provided separately. Also, although the first damping plate portion 43 and the second damping plate portion 6 were described as flat plates, the invention is not limited to this. For example, when the shutter body 4 is rotated between the open position and the shielded position, protrusions 430a and 60a may be formed on the lower surface of the first damping plate portion 430 and the upper surface of the second damping plate portion 60 to prevent the shutter body 4 from interfering with other parts, and the space 440 may be made into a labyrinth space to more reliably suppress the arrival of the deposition material Es on the substrate Gs (see Figure 3). Furthermore, although the above embodiments were described in which the shutter body 4 is rotated, the present invention can also be applied to a system in which the shutter body 4 is moved horizontally in one direction. Furthermore, in the above embodiment, the shutter body 4 was described as having an inverted dish shape with a plate portion 41, but the shutter body 4 is not limited to this as long as it can reflect the vapor-deposited material Em multiple times on its inner surface, for example, it may have a bell-shaped contour.
[0020] Incidentally, for example, after heating of the deposition material Em by the heating means 3 at the shielding position of the shutter body 4, an instrument for measuring the deposition rate, such as a quartz crystal film thickness monitor, may be placed on the anti-deposition plate 6 in order to confirm the stability of the deposition rate. In such cases, a slit opening (not shown) facing the film thickness monitor is provided so as to span the first damping plate portion 43 and the skirt portion 42, and the deposition rate is measured from the deposition material Em emitted through the slit opening. For this reason, the "annular" first damping plate portion referred to in the present invention also includes cases in which, for example, a slit opening is formed in a part thereof. When a slit opening is formed, the deposition material Em will be emitted toward the substrate Gs through the slit opening, so it is preferable to provide another shielding plate to suppress the arrival of the deposition material Em on the substrate Gs as much as possible. [Explanation of symbols]
[0021] ES1 to ES3... Evaporation sources for a vacuum evaporation apparatus, Em... Evaporation material, 2... Crucible, 21... Discharge opening, 3... Heating means, Sh... Shutter, 4... Shutter body, 41... Base plate portion (base end portion), 42... Skirt portion, 43... First attenuation plate portion, 6... Anti-deposition plate (second attenuation plate portion), 61... Opening, 430a, 60a... Protrusions.
Claims
1. A deposition source for a vacuum deposition apparatus, which is placed inside a vacuum chamber and used for depositing material onto a material to be deposited, The device comprises a crucible for containing a deposition material and having an outlet opening on its upper surface, a heating means for heating the deposition material inside the crucible, and a shutter for selectively blocking the scattering path of the deposition material released from the outlet onto the object to be deposited. The shutter comprises a shutter body having a base end and a skirt portion hanging down from the base end, and a drive source that rotates the shutter body without vertical movement between a shielding position that blocks the scattering path and an open position that releases the discharge opening. A vapor deposition source for a vacuum deposition apparatus, characterized in that an annular first damping plate portion is provided at the lower end of the skirt portion, extending at least outward in a circumferential direction perpendicular to the vertical direction, and the first damping plate portion is configured to form a circumferentially extending space with a second damping plate portion positioned around the crucible within the vacuum chamber.
2. The deposition source for a vacuum deposition apparatus according to claim 1, characterized in that a protrusion is formed on at least one of the first damping plate portion and the second damping plate portion, and the space is made a labyrinth space.
3. The deposition source for a vacuum deposition apparatus according to claim 1 or 2, characterized in that the upper surface of the second damping plate portion is set to a height position equal to or lower than the upper surface of the crucible.