JPH10102242A - Vacuum deposition device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously produce plural substrates having the same optical characteristics. SOLUTION: The inside of a vacuum chamber 10 is held to a prescribed vacuum state by a vacuum pump connected to a discharge port. In the case magnesium fluoride charged in a crucible 12 is irradiated with electron beams from an electron gun 13 simultaneously with the rotary movement of a shutter 15, vapor deposition onto substrates at the substrate placing parts of six substrate holders 30 arranged at the ceiling part of the vacuum chamber 10 and monitor glass 24 is started. The coating forming rate per substrate is detected by a coating thickness sensor provided at each substrate holder 30, and a control unit L1 regulates the distance from magnesium fluoride to the substrate per substrate based on the detected value and holds the coating forming rate of each substrate to certain one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vacuum deposition apparatus for forming a multilayer film such as a dielectric layer on a substrate such as an optical member by, for example, a vacuum deposition method.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for forming an optical thin film such as an antireflection film, a reflection increasing film, an optical filter film, etc. on a substrate,
2. Description of the Related Art A vacuum evaporation apparatus is known in which a plurality of substrates are set in a single holder disposed at the top of a device in a vacuum atmosphere, and a thin film is formed on each substrate by evaporating an evaporation source, which is a dielectric material, from the bottom of the device. Have been. The optical thin film formed on each substrate is a multilayer film composed of a plurality of dielectric layers, and is required to give each substrate the same optical characteristics. That is, the thickness of each layer constituting the thin film formed on each substrate must be formed uniformly so as not to vary on each substrate. As an apparatus for forming such a uniform film thickness, an apparatus for rotating a dome-shaped substrate holder on which a large number of substrates are set on an evaporation source to form a uniform film thickness in the circumferential direction of the substrate holder, An apparatus or the like is known which fixes a film thickness correction plate between a substrate holder and an evaporation source to make the film thickness in the radial direction of the substrate holder uniform.

However, in these apparatuses, conditions for forming a thin film on a substrate are influenced by factors such as the vacuum atmosphere in the apparatus, the degree of evaporation of an evaporation source, the degree of setting of a substrate holder, and the like. It is difficult to keep all the substrates set in the substrate holder in the same state, and thus it has been difficult to form a thin film having a uniform thickness on all the substrates.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a vacuum capable of obtaining the same optical characteristics by accurately controlling the thickness of thin films formed on a large number of substrates. It is intended to provide a vapor deposition device.

[0005]

SUMMARY OF THE INVENTION A vacuum deposition apparatus according to the present invention includes a plurality of substrate holders provided in a vacuum chamber and capable of holding a substrate, and evaporating means provided in the vacuum chamber. In a vacuum deposition apparatus for forming a thin film on a substrate by means, each of a plurality of substrate holders,
A film forming speed measuring means for measuring a film forming speed of a thin film, and a film forming speed controlling means for controlling a film forming speed based on a measurement result of the film forming speed measuring means are provided.

[0006] For example, the film forming speed control means controls the film forming speed by controlling the distance between the substrate holder and the vapor deposition means.

[0007] Preferably, the film forming speed control means has a first end on which a substrate mounting portion for holding the substrate is fixed, and a first end on the opposite side to the end on which the substrate mounting portion is fixed. , A second gear meshing with the first gear, and a motor for driving the second gear. The first and second gears are rotated by rotating the motor. To move the shaft in the longitudinal direction thereof to control the distance between the substrate and the evaporating means.

For example, the first gear is a linear gear disposed along the longitudinal direction of the shaft, the second gear is a rotating gear, and the motor is a stepping motor.

Preferably, the second gear and the motor are located outside the vacuum chamber, the substrate mounting portion is located inside the vacuum chamber, and the film forming speed control means is provided so that the shaft passes through one side of the vacuum chamber. It is arranged.

Preferably, the vacuum evaporation apparatus further includes a transmittance measuring means, and operates the evaporating means until the transmittance measuring means detects a predetermined transmittance.

For example, the film forming speed measuring means has a quartz oscillator.

Preferably, one substrate is held in each of the substrate holders.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the vacuum evaporation apparatus according to the present embodiment. The inside of the vacuum chamber 10
A predetermined vacuum state is maintained by a vacuum pump (not shown) connected to the exhaust hole 11. At approximately the center of the bottom surface inside the vacuum chamber 10, a crucible 12 is rotatably disposed on the bottom surface by a rotating column 12a. The crucible 12 is filled with MgF ₂ (magnesium fluoride) as a first evaporation material and ZrO ₂ (zirconium dioxide) as a _second evaporation material. A cover 14 is provided above the crucible 12 to prevent one of the evaporating materials filled in the crucible 12 from being mixed into another evaporating material when evaporating. An electron gun 13 is fixed to the bottom of the vacuum chamber 10 near the crucible 12 by a fixture 13a. Shutter 15
Is supported by a supporting column 15b, and the supporting column 15b is rotatably disposed on the bottom surface of the vacuum chamber 10 by a rotating column 15a. Accordingly, the shutter 15 is rotatable about the support column 15b, and is set at a position where the evaporation material is not blocked from evaporating during the vacuum deposition on the substrate. Positioned to block the evaporative material from flying upwards.

A window 21 is formed at the edge of the bottom of the vacuum chamber 10 near the exhaust hole 11. Further, a window 22 is provided in a portion of the ceiling of the vacuum chamber 10 facing the window 21. A monitor glass holder 23 for holding a monitor glass 24 is provided below the window 22. The monitor glass holder 23 is fixed to the ceiling of the vacuum chamber 10. A light source 25 is provided near the window 21 outside the vacuum chamber 10, and a photodetector 26 is provided near the window 22. The light source 25 is connected to a control device L2 outside the vacuum chamber 10. The light emitted from the light source 25 under the control of the control device L2 passes through the window 21 and passes through the transparent monitor glass 24.
The light transmitted through the monitor glass 24 passes through the window 22 and reaches the light detector 26. The photodetector 26 is connected to the control device L2, and a signal indicating the transmittance of the monitor glass 24 is transmitted to the control device L2. Further, six substrate holders 30 (K) are provided on the ceiling of the vacuum chamber 10.
1, K2, K3, K4, K5, K6), and each substrate holder is connected to the control device L1 by cords i1 and i2.

FIG. 2 is a sectional view of the substrate holder 30 of the present embodiment. The substrate holder 30 includes a substrate mounting portion 31, a shaft 32, a support 33, a fixing portion 34, and a rotating gear support 3.
5. It has a stepping motor 37. Fixed part 34
A support 33 is mounted on the upper surface of the device, and a rotating gear support 35 and a stepping motor 37 are mounted on the upper surface of the support 33. A rotating gear 36 is provided inside the rotating gear support 35. The rotating shaft 36a of the rotating gear 36 is inserted through the side surface of the rotating gear support 35, and is connected to a stepping motor 37 provided outside the rotating gear support 35, and the rotation of the stepping motor 37 is applied to the rotating gear 36. Is transmitted. The stepping motor 37 is connected to the control device L1 by a code i2.

A substrate mounting portion 31 is fixed to one end of the shaft 32, and extends straight along the longitudinal direction of the shaft 32 on the opposite side of the substrate mounting portion 31 across the center of the shaft 32. A dynamic gear 38 is provided. Shaft 3
2 is disposed so that the fixed portion 34, the support 33, and the rotary gear support portion 35 are inserted, the linear motion gear 38 meshes with the rotary gear 36, and the substrate mounting portion 31 faces the lower surface of the fixed portion 34. Have been. Therefore, when the stepping motor 37 rotates, the shaft 32 can move in the vertical direction via the rotary gear 36 and the linear motion gear 38. A fluorine rubber O (not shown) is provided between the support 33 and the shaft 32.
A ring-shaped vacuum seal is provided.

A substrate 40 and a film thickness sensor 41 are provided on the substrate mounting portion 31. The film thickness sensor 41 has a crystal oscillator, and the resonance frequency of the crystal oscillator is transmitted to an external control device L1 by a code i1.

As shown in FIG. 1, the substrate holder 30 is disposed such that the shaft 32 passes through the ceiling of the vacuum chamber 10 and the lower surface of the fixing portion 34 contacts the outer surface of the ceiling of the vacuum chamber 10. Therefore, the substrate mounting part 31 of the substrate holder 30 is located inside the vacuum chamber 10, and the fixing part 34, the support 33, and the gear supporting part 35 are located outside the vacuum chamber 10. A vacuum seal (not shown) is provided between the bottom surface of the fixing portion 34 and the outer surface of the ceiling portion.

Next, the operation of the vacuum deposition apparatus of the present embodiment will be described. In FIG. 1, gas in a vacuum chamber 10 is exhausted from an exhaust hole 11 by an external vacuum pump, and the degree of vacuum in the vacuum chamber 10 is maintained at 1 × 10 ⁻³ Pa. Next, when a control signal is transmitted from the control device L2 to the crucible rotation shaft 12a via the code i3, the crucible rotation shaft 12a rotates around the axis according to the control signal. The crucible 12 also rotates with the rotation of the crucible rotation shaft 12 a, and MgF _2, which is the first evaporation material, loaded in the crucible 12 is set at the irradiation position of the electron beam emitted from the electron gun 13.

Next, when a control signal is transmitted from the control device L2 to the electron gun 13 via the code i4, the electron beam is emitted from the electron gun 13 along a trajectory indicated by a dashed line and is loaded into the crucible 12. It is irradiated on the MgF _2, MgF ₂
Is melted. At this time, a cover 14 is disposed above ZrO ₂ as the second evaporation material, and the molten Mg
Incorporation of F ₂ is prevented. In this state, a control signal is transmitted from the control device L2 to the shutter rotation shaft 15a of the shutter 15 via the code i5, and the rotation shaft 15a rotates a predetermined amount around the axis. The rotation of the rotation shaft 15a is
b, the shutter 15 is accordingly moved to the supporting column 15
b from the position covering MgF ₂ from above.
Move to a position where gF ₂ does not block deposition on the substrate and stop. As a result, a thin film of MgF ₂ starts to be formed on the substrate 40, the film thickness sensor 41, and the monitor glass 24 provided on each substrate holder 30.

In the film thickness sensor 41, the resonance frequency of the crystal oscillator changes with an increase in the film thickness to be formed, and the resonance frequency signal is transmitted to the control device L1 via the code i1. The control device L1 calculates the film thickness forming speed from the change amount of the resonance frequency. On the other hand, in the control device L1, 0.8 nm / sec is preset as a default value of the film formation average speed of each substrate, and the film formation speed calculated based on the resonance frequency signal of the film thickness sensor 41 and the default value are set. When the film forming speed is higher than a predetermined value, the stepping motor moves the substrate mounting portion 31 of the substrate holder 30 away from the crucible 12 of the evaporation source, and when the film forming speed is lower than the predetermined value, moves the substrate mounting portion 31 closer to the evaporation source. The drive amount of the motor 37 is determined and transmitted to the stepping motor 37 via the code i2. Substrate mounting part 3
1 moves away from the evaporation source, the film formation speed of the film formed on the substrate 40 disposed on the substrate mounting portion 31 decreases, and the substrate mounting portion 31 approaches the evaporation source, thereby reducing the substrate 4.
The formation speed of the film formed at 0 is increased. As described above, the film formation speed is calculated based on the resonance frequency signal detected by the film thickness sensor 41, and the distance from the crucible 12 of the evaporation source to the substrate 30 is adjusted so that the film formation speed always keeps a constant value. I do.

As shown in FIG.
The code i2 connecting the control device L1 to the control device L1 and the code i1 connecting the film thickness sensor 41 to the control device L1 are K1 to K1.
K6 is independent for each substrate holder. That is, since the measurement of the film formation speed and the adjustment of the distance from the evaporation source to the substrate are performed independently for each substrate, a predetermined film formation speed is maintained for each substrate.

On the other hand, the light source 25 is turned on by a control signal transmitted from the control device L2 via the code i6 at the start of the vapor deposition operation described above. The light source 25 is a monochromatic light source having a wavelength of 550 nm. The light beam emitted from the light source 25 is
The light passes through the monitor glass 24 and the window 22 and reaches the light detector 26. The transmittance of the monitor glass 24 is detected by the photodetector 26, and the transmittance signal is transmitted to the control device L2 via the code i7.

A predetermined value of the transmittance determined as follows is set in the control device L2. Monitor glass 2
4 and the average optical film thickness of each substrate 40 are measured in advance, and MgF ₂ and Z
The optical thickness of each thin film to be formed on the monitor glass 24, that is, a predetermined thickness is obtained by multiplying the optical thickness of the rO ₂ thin film by this ratio. Furthermore, MgF is applied to the monitor glass 24.
The value of the transmittance of the monitor glass 24 when the film thickness ₂ is formed and reaches a predetermined film thickness, and the value of the transmittance of the monitor glass 24 when ZrO ₂ is formed thereon and the film thickness is a predetermined value. Is calculated based on the above formula, and is set in the control device L2 as a predetermined value of the transmittance.

When the transmittance indicated by the transmittance signal transmitted from the photodetector 26 via the code i7 reaches the predetermined value of the transmittance of MgF ₂ thus set, the control device L2 causes the shutter 15 to operate. A control signal for rotating to a position covering the upper portion of MgF ₂ and stopping is output, and the control signal is transmitted to the rotating column 15b via the code i5. At the same time, a control signal for terminating the electron beam irradiation to the electron gun 13 is transmitted to the electron gun 13 via the code i4, and the MgF ₂ vapor deposition processing ends.

The spectral reflectance of each substrate on which the MgF ₂ thin film was formed as described above was measured, and the result of calculating the optical film thickness of each substrate from the extreme value of the reflectance and the average of the film forming speed were calculated. It is shown in Table 1 of FIG. As is clear from Table 1, the optical film thickness of each substrate is in the range of 135.9 to 136.2 nm, and thin films having substantially the same film thickness are formed. Therefore, each substrate has the same optical characteristics when MgF ₂ is formed.

Next, a control signal is output from the control device L2 to the rotary column 12a of the crucible 12 via the code i3,
The rotating column 12a rotates around the axis in accordance with the control signal, and accordingly the crucible 12 rotates around the axis, and ZrO _{2 as} the second evaporation material is determined at the irradiation position of the electron beam emitted from the electron gun 13. Can be Thereafter the substrate 40 by the same procedure as MgF _2, thickness sensor 41, the monitor glass 24 Z
While the film of rO ₂ starts to be formed and until the transmittance of the monitor glass 24 reaches the predetermined value of the transmittance of ZrO ₂ calculated as described above, the film forming speed is maintained at a predetermined value while maintaining the predetermined value. A thin film having substantially the same thickness is formed on the substrate.

By depositing MgF ₂ and ZrO ₂ alternately with a predetermined thickness in the above-described vapor deposition operation, a thin film composed of a plurality of layers is formed on each substrate.

As described above, in the present embodiment, the adjustment of the film formation speed of the substrate 40 is performed independently for each substrate by the control device L1 based on the same reference value, and the film formation time is controlled. Since the respective substrates are commonly controlled by the apparatus L2, variations in the film thickness among the substrates due to the position of each substrate in the vacuum chamber 10 and the evaporation condition of the evaporation source are prevented, and the same optical characteristics are obtained. Can be simultaneously formed on a plurality of substrates.

Further, in the present embodiment, between the support 33 of the substrate holder 30 and the shaft 32, and between the support 33 and the substrate holder 30
Since a vacuum seal is provided between the fixing portion 34 of the vacuum chamber 10 and the outer surface of the ceiling of the vacuum chamber 10, the shaft 32
The air is prevented from flowing into the vacuum chamber even if moves vertically, and the degree of vacuum during deposition is kept constant.

In the present embodiment, six substrate holders are provided on the ceiling of the vacuum chamber 10, but the present invention is not limited to this, and as many substrate holders as the space on the ceiling of the vacuum chamber permits. May be arranged.

In this embodiment, Mg is used as the evaporation material.
The crucible 12 is filled with F ₂ and ZrO _2, but the present invention is not limited to this, and the type and number of evaporating materials may be selected according to what optical characteristics a thin film is formed on the substrate. .

[0033]

As described above, according to the present invention, a plurality of substrates having the same optical characteristics can be manufactured simultaneously.

[Brief description of the drawings]

FIG. 1 is a sectional view of a vacuum evaporation apparatus of the present invention.

FIG. 2 is a cross-sectional view of the substrate holder of the present invention.

FIG. 3 is a correspondence table of an optical film thickness and an average film formation speed on each substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum chamber 11 Exhaust hole 12 Crucible 13 Electron gun 14 Cover 15 Shutter 21, 22 Window 24 Monitor glass 25 Light source 26 Photodetector 30 Substrate holder 31 Placement part 32 Shaft 33 Support body 34 Fixed part 35 Rotating gear support part 36 Rotation Gear 37 Stepping motor 38 Linear gear

Claims (10)

[Claims] 1. A vacuum chamber, comprising a plurality of substrate holders capable of holding a substrate, and a vapor deposition means provided in the vacuum chamber, wherein a thin film is formed on the substrate by the vapor deposition means. In the vacuum evaporation apparatus, a film formation speed measuring unit that measures a film formation speed of the thin film, and a film formation speed of the thin film is controlled based on a measurement result of the film formation speed measurement unit on each of the plurality of substrate holders. A vacuum deposition apparatus comprising a film formation speed control means. 2. The vacuum evaporation apparatus according to claim 1, wherein the film formation speed control means controls a film formation speed by controlling a distance between the substrate holder and the vapor deposition means. 3. The film forming speed control means includes a substrate mounting portion for holding the substrate fixed at one end, and a film mounting speed control means provided at an end opposite to the end to which the substrate mounting portion is fixed. Comprises a shaft provided with a first gear, a second gear that meshes with the first gear, and a motor that drives the second gear. First
The vacuum evaporation apparatus according to claim 2, wherein the shaft is moved in a longitudinal direction of the shaft via a second gear, and a distance between the substrate and the evaporation unit is controlled. 4. The vacuum deposition apparatus according to claim 3, wherein the first gear is a linear gear disposed along a longitudinal direction of the shaft. 5. The vacuum deposition apparatus according to claim 3, wherein the second gear is a rotating gear. 6. The vacuum deposition apparatus according to claim 3, wherein the motor is a stepping motor. 7. The second gear and the motor are located outside the vacuum chamber, the substrate mounting part is located inside the vacuum chamber, and the shaft passes through one side of the vacuum chamber. 4. The vacuum deposition apparatus according to claim 3, wherein said film forming speed control means is provided. 8. The vacuum evaporation apparatus according to claim 1, wherein the vacuum evaporation apparatus further includes a transmittance measurement unit, and activates the deposition unit until the transmittance measurement unit detects a predetermined transmittance. Vacuum evaporation equipment. 9. The vacuum deposition apparatus according to claim 1, wherein said film forming speed measuring means includes a quartz oscillator. 10. The vacuum evaporation apparatus according to claim 1, wherein one of the substrates is held in each of the substrate holders.