JP5013591B2 - Vacuum deposition equipment - Google Patents

Description

  The present invention relates to a vacuum deposition apparatus.

In order to manufacture various semiconductor elements and organic EL (electroluminescence) elements, vacuum deposition apparatuses are widely used. The vacuum deposition apparatus forms a deposition material evaporated from an evaporation source in a vacuum chamber on a substrate to be a deposition target.
However, there is a problem in that the vapor deposition material from the evaporation source adheres to other parts of the vacuum chamber before reaching the substrate, and the utilization efficiency of the vapor deposition material decreases. Therefore, a technique is disclosed in which the path from the evaporation source to the substrate is surrounded by a wall, and the wall surface is heated so that the vapor deposition material does not accumulate (see Patent Document 1). In addition, a technique is disclosed in which a distribution correction plate is provided in the wall (cylindrical body) described above to control the deposition distribution of the vapor deposition material (see Patent Document 2).

  On the other hand, a technique is disclosed in which a vapor deposition material from a crucible (deposition source) is introduced into a pressure buffer chamber through a valve, and the vapor deposition material is attached to the substrate from the pressure buffer chamber via a long slit-shaped molecular discharge port. (See Patent Document 3). According to this technique, the vapor deposition material from the crucible (deposition source) is not directly emitted but is introduced into a predetermined space (pressure buffer chamber), and after adjusting the vapor pressure to a stable equilibrium pressure, it is discharged from the slit. . For this reason, it is said that the uniformity of film thickness becomes high over a wide range of the substrate.

JP 2002-80961 A JP 2003-129231 A JP 2004-307877 A

  By the way, in recent years, the required characteristics of the deposited film tend to be high, and it is necessary to control the orientation state of the film. However, a vacuum deposition apparatus that can easily adjust the incident angle of the deposition material to the substrate has not been developed. In particular, as described above, no technique has been developed that can obtain a uniform film thickness over a wide range of the substrate without reducing the utilization efficiency of the vapor deposition material.

  The present invention has been made to solve the above-described problems, and can easily adjust the incident angle of the vapor deposition material to the substrate, has high utilization efficiency of the vapor deposition material, and has a uniform film thickness over a wide range of the substrate. An object of the present invention is to provide a vacuum deposition apparatus that can obtain the above.

  In order to achieve the above object, a vacuum vapor deposition apparatus according to the present invention includes a crucible containing a vapor deposition material, a first heating mechanism for heating the vapor deposition material in the crucible, and one end connected to the opening of the crucible. And a tube-shaped diffusion chamber having a nozzle for discharging the gas, and the diffusion chamber is configured to rotate about a central axis. One end is rotatably supported by the other end of the conduit, the nozzle protrudes along the axial direction of the diffusion chamber, and the tip opens in the form of a long slit, and the conduit, the diffusion chamber, and the nozzle A second heating mechanism for preventing adhesion of the vapor deposition material is provided outside.

With such a configuration, the nozzle rotates as the diffusion chamber 10 rotates about the central axis, and the incident angle of the vapor deposition material gas on the substrate facing the nozzle changes. Thereby, the orientation angle of the deposited film to the substrate can be controlled, and the orientation film can be formed or the quality of the coating film can be made constant.
Furthermore, by heating the second heating mechanism to about the melting point of the vapor deposition material, the vaporized material adhering to the inner wall of the conduit, the diffusion chamber, and the nozzle is re-evaporated and scattered, so that the yield is improved.

It is preferable that a porous plate is disposed in the opening of the crucible.
With such a configuration, when the vapor deposition material heated in the crucible bumps due to non-uniform heat transfer, the vapor deposition material is prevented from scattering, and the path after the introduction (diffusion chamber, nozzle) is accompanied by bumping. To reduce pressure fluctuations.

It is preferable that a minute outlet is opened in a part of the conduit, and a quartz crystal vibrator for measuring the amount of the gas flowing out from the outlet is arranged in the vicinity of the outlet.
With such a configuration, it is possible to calculate the amount of the vapor deposition material flowing through the conduit, and it becomes easy to control the deposition amount of the vapor deposition material.

When the conductance of the diffusion chamber is C1, and the conductance of the nozzle is C2, the ratio represented by C1 / C2 is preferably 12 or more.
With such a configuration, the vapor deposition material gas is sufficiently diffused into the diffusion chamber, the pressure in the vicinity of the nozzle is constant, and the release of the vapor deposition material is stabilized, so that the vapor deposition of the vapor deposition material becomes uniform.

It is preferable that a plurality of louver blades that are rotatable around a rotation axis parallel to the short direction of the slit-shaped opening are arranged in parallel along the longitudinal direction of the opening on the inner side of the nozzle tip.
With such a configuration, since the ejection of gas from the nozzle opening can be adjusted, the difference in the adhesion amount in the width direction of the substrate can be reduced by adjusting the angle of the louver blade.

On the outside of the nozzle tip, a pair of protection plates are arranged along the longitudinal direction of the slit-like opening and sandwiching the opening, and the tip of each protection plate protrudes from the opening. Preferably it is.
With such a configuration, the vapor deposition material gas popping out from the nozzle tip is regulated by the deposition preventive plate, so that the vapor deposition range is narrowed and the incident angle to the substrate is limited. Therefore, the quality of the film is improved. Further, since the deposition preventing plate blocks the radiation of heat from the nozzle tip opening to the substrate, it prevents an adverse effect on an organic film or the like previously formed on the substrate, for example.

Of the pair of deposition preventing plates, it is preferable that at least the deposition preventing plate close to the substrate has a cooling mechanism.
With such a configuration, it is possible to prevent the temperature of the deposition preventing plate from rising when the deposition preventing plate blocks the radiation of heat from the nozzle tip opening.

  According to the present invention, the yield in vacuum vapor deposition is high, and the uniformity of film formation can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of a vacuum evaporation apparatus according to an embodiment of the present invention. In this figure, the vacuum vapor deposition apparatus is arranged in a vacuum chamber (not shown), a crucible 2 for accommodating the vapor deposition material, a first heating mechanism (heater) 4 for heating the vapor deposition material in the crucible 2, and one end 6 a at the crucible 2. And a diffusion chamber 10 having a nozzle 8. The conduit 6 rises vertically from the opening 2a of the crucible 2, and is then bent by 90 ° in the lateral direction to reach the other end 6b.
As the crucible 2, metal, ceramic or the like can be used, and as the first heating mechanism 4, a sheath heater, induction heating, infrared heating or the like can be used.

The diffusion chamber 10 has a cylindrical shape with both ends closed, the center of the end surface 10a is opened in a circular shape, and the cylindrical surface of the diffusion chamber 10 is opened in a long slit shape and connected to the nozzle 8. The other end face opposite to the end face 10 a is connected concentrically with the drive mechanism (stepping motor) 20, and the center opening edge of the end face 10 a is rotatably supported by the other end 6 b of the conduit 6. The diffusion chamber 10 rotates about its central axis.
The diffusion chamber 10 is supported on the conduit 6 by inserting the other end 6b of the conduit 6 from the center opening of the end surface 10a of the diffusion chamber 10 into the inside, and an O-ring between the other end 6b and the opening edge of the end surface 10a. , Bearings, bearings and the like. When a bearing, a bearing, or the like is used, it is preferable to seal these gaps with a sealing material or an O-ring so that the vapor deposition material gas does not leak from the gap between the other end 6b and the end face 10a.

  The nozzle 8 is a rectangular tube having a long rectangular cross section, and the bottom of the nozzle 8 is connected to the slit-shaped opening edge of the cylindrical surface of the diffusion chamber 10 so that the long cross section extends along the axial direction of the diffusion chamber 10. Has been. The nozzle 8 protrudes along the axial direction of the diffusion chamber 10, and its tip is opened in a long slit shape. Then, the gas of the vapor deposition material flows into the diffusion chamber 10 from the crucible 2 through the conduit 6 through the central opening of the end face 10 a, is discharged from the tip of the nozzle 8 through the slit-like opening on the cylindrical face, and enters the nozzle 8. It vapor-deposits on the surface of the board | substrate 50 which opposes.

The width direction W of the substrate 50 is parallel to the longitudinal direction of the nozzle 8, and the evaporation proceeds by relative movement in the L direction perpendicular to the width direction W. Since the nozzle 8 is long and the vapor deposition region is elongated, it is possible to uniformly vapor-deposit on a large and wide substrate.
The substrate 50 is usually supported by a substrate holder and is transported from another process into the vacuum deposition apparatus by a predetermined moving mechanism. Alternatively, the substrate 50 side may be fixed, and the vacuum evaporation apparatus may be moved in the L direction to advance the evaporation.

A pair of adhesion prevention plates 12a and 12b are arranged along the longitudinal direction of the opening of the nozzle 8 and spaced apart from each other on the outer part from the cylindrical surface of the diffusion chamber 10 to the tip of the nozzle 8. Yes. Further, the tips of the respective adhesion preventing plates 12 a and 12 b protrude from the opening of the nozzle 8. The operation of the adhesion preventing plates 12a and 12b will be described later.
On the outside of the conduit 6, the diffusion chamber 10, and the nozzle 8, second heating mechanisms (heating wires) 14, 16, and 18 for preventing the deposition material from adhering are wound.

As described above, the diffusion chamber 10 can rotate about the central axis Ax, and the nozzle 8 rotates accordingly, and the incident angle of the vapor deposition material gas 40v on the substrate 50 facing the nozzle 8 changes. Thereby, the orientation angle of the deposited film to the substrate can be controlled, and the orientation film can be formed or the quality of the coating film can be made constant.
Further, when the deposition preventing plates 12a and 12b are not provided, the vapor deposition material gas 40v spreads and is emitted from the tip of the nozzle 8 and is incident on the substrate over a wide range from various angles and directions, so that the film quality is not uniform. Tend to be. On the other hand, when the deposition preventing plates 12a and 12b are arranged at positions protruding from the tip of the nozzle 8 (toward the substrate 50 side), the vapor deposition material gas 40v jumping out from the tip of the nozzle 8 is regulated by the deposition preventing plates 12a and 12b. And the angle of incidence on the substrate is limited. Therefore, the quality of the film is improved.
As will be described later, the deposition preventing plate shields radiation of heat from the nozzle tip opening to the substrate, so that it is possible to prevent adverse effects on, for example, an organic film formed in advance on the substrate. In order to prevent the temperature of the deposition preventing plate from rising when the deposition preventing plate radiates heat from the nozzle tip opening, at least the deposition preventing plate on the side close to the substrate. (For example, the adhesion-preventing plate 12a in FIG. 1) preferably includes a cooling mechanism. Of course, you may provide a cooling mechanism in both a pair of adhesion prevention plates. An example of the cooling mechanism is a water cooling jacket.

  Further, by heating the second heating mechanism 14, 16, 18 to about the melting point of the vapor deposition material, the vaporized material adhering to the inner wall of the conduit 6, the diffusion chamber 10, and the nozzle 8 is re-evaporated and scattered. , Improve the yield.

In this embodiment, a small diameter pipe (orifice) 6c extending in the direction opposite to the bending direction is provided in the vicinity of the bent portion of the conduit 6, and the tip of the pipe 6c forms a minute outlet. . In the vicinity of the tip (outlet) of the pipe line 6c, a quartz crystal vibrator 22 is arranged opposite to measure the amount of vapor of the vapor deposition material flowing out from the outlet.
The amount of the vapor deposition material per unit time can be measured by the crystal oscillator 22, and the amount of the vapor deposition material flowing through the conduit 6 per unit time can be calculated. Note that the smaller the flow rate of the pipeline 6c, the better. However, if the pipeline 6c is too thin, clogging or the like occurs. Therefore, normally, the flow rate of the pipe 6c is preferably about 1% or less with respect to the flow rate of the conduit 6.

2 is a cross-sectional view taken along the line II-II in FIG. 1, and the line II-II is perpendicular to the axial direction of the diffusion chamber 10. In FIG. 2, the crucible 2 has a bottomed cylindrical shape and accommodates the vapor deposition material 40 inside the cylinder. A supply port for the vapor deposition material 40 may be provided at a predetermined position of the crucible 2.
A porous plate (baffle) 24 is disposed in the upper surface opening of the crucible 2, and the vapor deposition material 40 heated by the first heating mechanism (heater) 4 disposed outside the crucible 2 is porous from the upper surface opening of the crucible 2. It is led to the conduit 6 via the plate 24.
The perforated plate 24 prevents the vapor deposition material 40 from splashing when the vapor deposition material 40 heated in the crucible 2 is bumped due to non-uniform heat transfer. , Including the inside of the nozzle). Thereby, the discharge pressure of the vapor deposition material gas from the nozzle 8 can be kept constant, and uniform film formation can be performed.
The opening area of the perforated plate 24, the diameter and distribution of each hole, and the like can be determined as appropriate in accordance with the device environment used.

  Next, the shape of the nozzle 8 will be described. In the present invention, the opening of the nozzle 8 has a long slit shape. Therefore, the opening area of the nozzle tip is relatively small, the ratio of radiation heat from the inside of the nozzle being radiated to the substrate is small, and temperature rise on the substrate surface can be prevented. For example, when an organic film or the like is previously formed on the substrate, damage to the film due to thermal damage can be prevented. Furthermore, prevention of radiant heat from the nozzle tip can also be promoted by the above-described deposition preventing plate. Further, since the opening of the nozzle 8 is slit-shaped, the opening area is smaller than the inner volume of the diffusion chamber, and the vapor deposition material gas can be uniformly discharged in the longitudinal direction of the nozzle due to the difference in conductance with the diffusion chamber. Become.

As the pressure of the vapor deposition material gas in the diffusion chamber increases, the gas gradually changes from a molecular flow behavior to a viscous flow behavior, and the gas diffuses uniformly at each position of the nozzle. However, since the pressure inside the vacuum vessel is usually 10 ⁻³ to 10 ⁻⁵ Pa level, the vapor deposition material gas near the nozzle tip causes gas flow disturbance due to the pressure difference from the inside of the nozzle, and is sufficiently viscous and fluid. It may not behave. Therefore, when the louver described later is used, the above-described pressure disturbance can be corrected.
Here, when the mean free path is sufficiently longer than the diameter of the container, the collision frequency between the gas particles is small, and the collision with the inner wall becomes dominant as the movement of the gas particles, and the gas behaves like a molecular flow. On the other hand, when the gas particle density increases and the mean free path is shorter than the diameter of the container, the collision frequency between the gas particles increases, and the gas behaves like a viscous flow. If the flow is completely viscous, it is considered that the gas is distributed almost evenly in the nozzle portion due to the resistance of the diffusion chamber and the inner wall of the nozzle, and the distribution of the blowout from the nozzle tip is uniform to some extent.

In particular, the conductance when the central opening of the end surface 10a of the diffusion chamber is the inlet, the long slit-shaped opening of the cylindrical surface of the diffusion chamber 10 is the outlet is C1, and the conductance between the inlet and the outlet of the nozzle is C2. In this case, the ratio represented by C1 / C2 is preferably 12 or more.
C1 / C2 increases as the internal volume of the diffusion chamber increases and the cross-sectional area of the nozzle decreases. When C1 / C2 is less than 12, the vapor deposition material gas is not sufficiently diffused into the diffusion chamber, and the discharge from the nozzle is not stable, so that the vapor deposition of the vapor deposition material tends to be non-uniform. The value of C1 / C2 is more preferably 17 or more. However, since the size of the entire apparatus (diffusion chamber) is limited, the value is actually adjusted according to the shape and volume of the diffusion chamber and the nozzle.
Conductance can be calculated by actually measuring the flow rate at the inlet and outlet of the container.

Further, as shown in FIG. 3, it is preferable to provide a louver blade inside the tip of the nozzle 8 because the flow rate of the vapor deposition material gas can be adjusted in the longitudinal direction of the nozzle opening and the vapor deposition amount distribution can be made uniform. In FIG. 3, a plurality of plate-like louver blades 26 are juxtaposed along the longitudinal direction of the opening of the nozzle 8 (parallel to the W direction W). Each louver blade 26 is supported by a rotation shaft 28 parallel to the short direction of the opening of the nozzle 8 and is rotatable about the rotation shaft 28.
Now, in FIG. 3, the actual experimental result when the nozzle opening is closed with the louver blade 26 located on the right side (opposite the connecting portion with the conduit 6) from the center S of the nozzle 8 is based on FIG. I will explain.

FIG. 4 shows that the longitudinal length of the opening of the nozzle 8 is 360 mm, the short length is 8 mm, the vacuum during vapor deposition is kept at about 10 ⁻⁴ Pa, Alq ₃ is used as the vapor deposition material, and the crucible 2 The thickness distribution of the deposited film in the W direction of the substrate 50 when actual deposition is performed at a heating temperature of about 300 ° C. is shown.
The horizontal axis of FIG. 4 indicates the distance in the W direction from the center of the substrate, and the vertical axis indicates the ratio of the film thickness at each position in the width direction of the substrate when the maximum film thickness in the width direction of the substrate is 1. (Hereinafter referred to as “film thickness ratio”).

When all the louver blades were made vertical (same as the case where there was no louver blade) (curve T1 in FIG. 4), the film thickness was maximized at a portion slightly on the right side from the center S. This is presumably because the flow state differs in the left-right direction (W direction) of the nozzle 8 due to the conduit 6 being connected to the left side of the nozzle 8. In this case, the average value of the film thickness ratio at each position of the substrate is obtained, and the standard deviation of the film thickness ratio is obtained, and (standard deviation of the film thickness ratio) / (average value of the film thickness ratio at each position). The calculated rate of change was 0.94
It became.
On the other hand, when the louver blade on the right side of the center S is closed over a length of 60 mm in order to reduce the gas ejection to the portion with the maximum film thickness (curve T2 in FIG. 4), the portion with the maximum film thickness. Moved to the vicinity of the center of the substrate, the variation rate decreased to 0.59, and the variation of the film thickness in the width direction (W) of the substrate was greatly reduced. Thus, by adjusting the louver blade, the difference in film thickness in the width direction of the substrate can be reduced.

It is a whole lineblock diagram of the vacuum evaporation system concerning the embodiment of the present invention. It is sectional drawing which follows the II-II line | wire of FIG. It is sectional drawing which follows the III-III line of FIG. It is a figure which shows the film thickness distribution of the width direction of a board | substrate.

Explanation of symbols

2 crucible 2a crucible opening 4 first heating mechanism 6 conduit 6a one end of conduit 6b other end of conduit 8 nozzle 10 diffusion chamber 10a one end of diffusion chamber 14, 16, 18 second heating mechanism

Claims (7)

A crucible containing a vapor deposition material, a first heating mechanism for heating the vapor deposition material in the crucible, a conduit having one end connected to an opening of the crucible and passing a gas of the vapor deposition material generated from the crucible, A cylindrical diffusion chamber having a nozzle for discharging gas,
One end of the diffusion chamber is rotatably supported on the other end of the conduit so that the diffusion chamber rotates about a central axis;
The nozzle protrudes along the axial direction of the diffusion chamber, and its tip opens in the form of a long slit,
Vacuum deposition apparatuses each having a second heating mechanism for preventing adhesion of the deposition material on the outside of the conduit, the diffusion chamber, and the nozzle. The vacuum deposition apparatus according to claim 1, wherein a perforated plate is disposed in the opening of the crucible. 3. A crystal resonator for measuring a quantity of the gas flowing out from the outlet is disposed near the outlet, and a minute outlet is opened in a part of the conduit. Vacuum deposition equipment. The vacuum deposition apparatus according to any one of claims 1 to 3, wherein a ratio represented by C1 / C2 is 12 or more, where C1 is a conductance of the diffusion chamber and C2 is a conductance of the nozzle. 2. A plurality of louver blades that are rotatable about a rotation axis parallel to a short direction of the slit-shaped opening are arranged in parallel along the longitudinal direction of the opening on the inner side of the nozzle tip. The vacuum evaporation apparatus in any one of 4. On the outside of the nozzle tip, a pair of protection plates are arranged along the longitudinal direction of the slit-like opening and sandwiching the opening, and the tip of each protection plate protrudes from the opening. The vacuum evaporation apparatus according to any one of claims 1 to 5. The vacuum deposition apparatus according to claim 6, wherein at least one of the pair of deposition preventing plates on the side close to the substrate includes a cooling mechanism.

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