JPH1183445A - Film thickness monitor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film thickness monitor device capable of monitoring the film thickness of a large number of thin films accurately. SOLUTION: The film thickness monitor device is fixed in a vacuum vessel of a thin film formation device. The thin film monitor device is provided with a high speed rotation disk 16, a slit unit 18 covering the whole area of the bottom face of the disk 16 and having a slit S formed along the orthogonal direction to a disk 16 radius direction and movable in the disk 16 radius direction, and a photo reflector unit 35 movable in the disk 16 radius direction, irradiating light on a ring-like monitoring thin film formed on the disk 16 bottom face by material substance passed the slit S, and receiving reflection light from the monitoring thin film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film thickness monitor for monitoring the thickness of a thin film formed on a substrate in a thin film forming apparatus.

[0002]

2. Description of the Related Art A thin film forming apparatus is an apparatus for forming an extremely thin thin film in a vacuum chamber according to a vacuum evaporation method or a sputtering method. When the substrate on which a thin film is formed by such a thin film forming apparatus is, for example, an optical member or a semiconductor, the thickness of the thin film greatly affects the performance of the substrate. Therefore, the amount of thin film formation must be controlled by accurately monitoring the thickness of the thin film being formed.

[0003] For this reason, various thin film monitoring devices for monitoring the thickness of a substrate in a vacuum chamber in a non-contact manner have been proposed. FIG. 11 shows an example in which a monitor glass on which a thin film is formed in the same manner as a substrate is installed in a vacuum evaporation apparatus, and the reflectance of the monitor glass surface is optically measured from outside the vacuum chamber (evaporation pot). 1 shows a configuration of a thin film monitor device.

[0004] In FIG. 11, air in a vacuum chamber (evaporation pot) 50, which is a substantially cylindrical closed container, is sucked by a vacuum pump 62 through an exhaust pipe 61 opened and closed by a valve 60. A crucible 54 for evaporating the evaporation material is provided on the bottom surface of the vacuum tank (evaporation pot) 50. An umbrella-shaped rack 51 having a through hole (not shown) for inserting a large number of optical members (lenses L) is rotatably mounted on the upper portion of the vacuum chamber (vaporization pot) 50. ing.

[0005] In the vacuum evaporation apparatus having the above-described basic configuration, the thin film monitoring apparatus is configured as follows. That is, in the middle of the vacuum chamber (evaporation pot) 50 (space below the rack 51), a flat circular flat tray-shaped tray 52 is provided.
It is supported by the book support rod 52b. On an upper surface of the receiving tray 52, a monitor glass 53 made of an annularly cut flat glass is placed. A through hole 52 a exposing a part of the lower surface of the monitor glass 53 toward the crucible 54 is formed at a position offset from the center of the tray 52. On the other hand, a vacuum tank (vaporization pot) 5
An observation window 50a in which a transparent glass 55 is inserted is formed beside the crucible 54 on the bottom surface of 0. Outside the observation window 50a, a light source lamp 56 that emits white light B toward the through hole 52a of the tray 52, and a through hole 52a
White light B transmitted through and reflected by the lower surface of the monitor glass 53
The mirror 57 that reflects the reflected light R of the side toward the side is disposed side by side. Then, the reflected light R reflected by the mirror 57 is extracted by the spectroscope 58 only at the used wavelength and detected by the detector 59.

With the above configuration, as the thin film formation on the optical member (lens L) proceeds in the vacuum evaporation apparatus, a thin film is also formed on the lower surface of the monitor glass 53 exposed through the through hole 52a of the tray 52. Is done. The thickness of the thin film formed on the monitor glass 53 is proportional to the thickness of the thin film formed on the optical member (lens L). Then, as the thin film formed on the monitor glass 53 becomes thicker, the reflectance of the lower surface of the monitor glass 53 with respect to the white light B emitted from the light source lamp 56 changes. Therefore, the thickness of the thin film formed on the optical member (lens L) can be measured by performing a predetermined operation on the output change amount of the detector 59 that has received the reflected light R.

If another thin film is to be formed after the formation of one thin film, the monitor glass 53 is rotated in the receiving tray 52 to form an area on the lower surface of the monitor glass 53 where the thin film has not yet been formed. Through hole 5 in receiving pan 52
2a. In this way, by rotating the monitor glass 53 each time one layer of thin film is formed, the thickness of the multilayer thin film can be monitored by one monitor glass 53.

[0008]

However, in the conventional film thickness monitor, the monitor glass 53 and the light source 56 are not provided.
Since the distance between the tray 52 and the detector 59 is long, the through-hole 52a of the tray 52 has to be enlarged. As a result, the ratio of the area of the through-hole 52a to the area of the monitor glass 53 increases, so that the rotation angle of each monitor glass 53 when rotating each time a thin film is formed increases. The number of thin film layers that can be monitored by the monitor glass 53 is limited. In order to increase the number of thin films that can be monitored with a single monitor glass 53, it is conceivable to simply increase the diameter of the monitor glass 53. The mechanism of the above becomes large, and the formation of the thin film on the optical member (lens L) is affected.

The present invention has been made to solve the above problems. That is, an object of the present invention is to provide a film thickness monitoring device capable of accurately monitoring the film thickness of a large number of thin films using one disk.

[0010]

The present invention has the following features to attain the object mentioned above. That is, claim 1
A film thickness monitor for monitoring a film thickness of a thin film in a thin film forming apparatus for forming a thin film by attaching a material diffused from a diffusion source to a surface of a substrate disposed in a vacuum chamber. A monitor device, a disk rotatably installed in a plane perpendicular to the center axis of the vacuum chamber, a rotation mechanism for rotating the disk, and a flat surface on the diffusion source side of the disk. A shielding member formed along a direction orthogonal to the radial direction of the disk and having a slit configured to be movable in the radial direction of the disk, and a shielding member of the disk facing a plane on the diffusion source side of the disk. When irradiating a thin film formed on the plane of the disk with the material passed through the slit of the shielding member and provided so as to be movable in the radial direction, A photo reflector for receiving the light reflected by the thin film, and a moving mechanism for moving said photo-reflector and the slit so that the same distance from the central axis of said disk, characterized by comprising.

With this configuration, the moving mechanism positions the slit and the photoreflector unit at the same distance from the center axis of the disk. The material diffused from the diffusion source passes through the slit and adheres and condenses on a portion of the disk plane facing the slit. Since the disk is rotated by a rotating mechanism in a plane perpendicular to the center axis, the material condensed on the disk plane forms a ring-shaped thin film having a uniform film thickness. The photo reflector irradiates the thin film with light and receives the reflected light, and outputs a reflected light amount signal used for calculating the reflectance of the thin film. Since the photo reflector is located at a position facing the plane of the disk, even if the thin film for monitoring is thin, it can accurately receive the reflected light from the thin film. Therefore, the slit can be made thinner to make the thin film for monitoring thin, so that a large number of thin films for monitoring can be formed on the disk plane. Further, since the optical path of the light reciprocating between the photoreflector and the disk has a short optical path, other light does not enter as noise.

According to a second aspect of the present invention, the thickness of the thin film is monitored in a thin film forming apparatus for forming a thin film by depositing a material diffused from a diffusion source on a surface of a substrate disposed in a vacuum chamber. A disk mounted in the vacuum chamber so as to be rotatable in a plane perpendicular to the center axis thereof, a rotation mechanism for rotating the disk, and the diffusion source side of the disk. And a shielding member having at least two slits formed along a direction perpendicular to the radial direction of the disk and configured to be movable in the radial direction of the disk, and passed through the first slit. A photo-irradiating light through the second slit to the thin film formed on the plane of the disk by the material and receiving reflected light And Furekuta, a moving mechanism for moving the respective slits so that the same distance from the central axis of said disk, characterized by comprising.

[0013] With this configuration, the slits are arranged at the same distance from the center axis of the disk by the moving mechanism. The material diffused from the diffusion source passes through the first slit and adheres and condenses on a portion of the disk plane facing the slit. Since the disk is rotated by a rotating mechanism in a plane perpendicular to the center axis, the material condensed on the disk plane forms a ring-shaped thin film having a uniform film thickness. The photo reflector irradiates the thin film with light through the second slit and receives the reflected light, and outputs a reflected light amount signal used for calculating the reflectance of the thin film. Since the photo reflector faces the disk with the second slit interposed, even if the thin film for monitoring is thin,
The reflected light from the thin film can be accurately received.
Therefore, the slit can be made thinner to make the thin film for monitoring thin, so that a large number of thin films for monitoring can be formed on the disk plane.

According to a third aspect of the present invention, the thickness of the thin film is monitored in a thin film forming apparatus for forming a thin film by attaching a material diffused from a diffusion source to a surface of a substrate arranged in a vacuum chamber. A disk mounted in the vacuum chamber so as to be rotatable in a plane perpendicular to the center axis thereof, a rotation mechanism for rotating the disk, and the diffusion source side of the disk. A shielding member formed along a direction perpendicular to the radial direction of the disk and having at least two slits configured to be movable in the radial direction of the disk; and the disk with the shielding member interposed therebetween. The first side is provided movably in the radial direction of the disk on the side opposite to the first side.
A photoreflector that irradiates light through a second slit to a thin film formed on the plane of the disk by the material passing through the slit and receives reflected light, A moving mechanism for moving the photoreflector so as to be at the same distance from the center axis of the disc.

With this configuration, the slits and the photoreflectors are arranged at the same distance from the center axis of the disk by the moving mechanism. The material diffused from the diffusion source passes through the first slit and adheres to a portion of the disk plane facing the slit.
Congeal. Since the disk is rotated by a rotating mechanism in a plane perpendicular to the center axis, the material condensed on the disk plane forms a ring-shaped thin film having a uniform film thickness. The photo reflector irradiates the thin film with light through the second slit and receives the reflected light, and outputs a reflected light amount signal used for calculating the reflectance of the thin film. The photo reflector is the second
Since the disk is opposed to the disk with the slit interposed therebetween, even if the thin film for monitoring is thin, the reflected light from the thin film can be accurately received. Therefore, the slit can be made thinner to make the thin film for monitoring thin, so that a large number of thin films for monitoring can be formed on the disk plane.

The thin film monitoring device to which the present invention is applied is a vacuum evaporation device or a sputtering device. Further, the light-shielding member is composed of two members that slide with respect to each other, and a slit that is oblique to the relative sliding direction of the two members is formed in one member, and the slit that is oblique to the slit is formed. May be formed on the other member, and the intersection of both slits may be "a slit configured to be movable in the radial direction of the disk".

According to a fourth aspect of the present invention, the shielding member according to any one of the first to third aspects has a first shielding member having a slide slit extending in a radial direction of the disk, and a sliding member sliding with respect to the slide slit. It is specified by being constituted by a second shielding member which is fitted as much as possible and in which the slit is formed.

According to a fifth aspect of the present invention, in accordance with any one of the first to third aspects, the reflectivity of the thin film formed on the disk is measured based on the amount of reflected light received by the photoreflector. This is specified by further providing the measurement unit.

According to a sixth aspect of the present invention, in the fifth aspect, a monitor film thickness calculating section for calculating the film thickness of a thin film formed on the disk based on the reflectance measured by the reflectance measuring section. It is specified by having further provided.

According to a seventh aspect of the present invention, in the sixth aspect, the substrate thickness is calculated based on the thickness calculated by the monitor thickness calculating section. This is specified by further providing the calculation unit.

According to an eighth aspect of the present invention, in the seventh aspect, a comparison unit for determining whether or not the film thickness calculated by the substrate film thickness calculating means has reached a target film thickness is further provided. It is specified.

According to a ninth aspect of the present invention, in accordance with the eighth aspect of the present invention, there is provided a control as described in the eighth aspect, wherein the diffusion of the material from the diffusion source is stopped when the comparing section determines that the thickness of the thin film has reached a target thickness. It is specified by further providing the unit.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. (Configuration of Vacuum Deposition Apparatus and Film Thickness Monitoring Apparatus) FIG. 1 is a schematic sectional view of a vacuum evaporation apparatus (thin film forming apparatus) incorporating a film thickness monitoring apparatus according to an embodiment of the present invention. FIG.
, The evaporation pot 1 (vacuum pot) has a cylindrical shape with a bottom, and the upper end is sealed by a dome-shaped top plate 1a. The internal space of the evaporation pot 1 communicates with a vacuum pump 4 through an exhaust pipe 2 opened and closed by a valve 3. The vacuum pump 4 discharges air molecules inside the evaporation vessel 1 to the outside through the exhaust pipe 2 and can reduce the pressure inside the evaporation vessel 1 to a high vacuum.

A crucible 5 (diffusion source) is provided at the center of the bottom surface 1b of the evaporation vessel 1 for evaporating an evaporation material (material) by a resistance heating element (not shown) and diffusing its molecules. When a multilayer film is formed by the vacuum evaporation apparatus, a plurality (for example, four or five) of the crucibles 5 are provided according to the type of evaporation material to be evaporated.

At the center of the top plate 1a, a rotating shaft 6a which is driven to rotate by a drive motor (not shown) is provided.
It penetrates coaxially and airtightly with the inner surface. An umbrella-shaped holder 6 that extends toward the bottom surface 1b of the vapor deposition vessel 1 is integrally fixed to the tip of the rotary shaft 6a (the end that has entered the vapor deposition vessel 1). The holder 6 has a plurality of lens holding holes penetrating the upper surface (outer surface) and the lower surface (inner surface) thereof, and each having a lens L as an optical member inserted therein.

In the space just below the holder 6 on the central axis of the evaporation vessel 1, a film thickness monitor 7 is held via four support rods 8 extending from the inner surface of the evaporation vessel 1. I have. Although FIG. 1 schematically shows the film thickness monitor 7 large because of the schematic cross-sectional view, in actuality, the size of the thin film monitor 7 is very small, so that the vapor deposition material on the lens L mounted on the holder 6 is Is not hindered by the thin film monitoring device 7.

FIG. 2 is an enlarged sectional view showing a schematic configuration of the film thickness monitoring device 7, and FIG. 4 is a detailed perspective view showing the film thickness monitoring device 7 viewed obliquely from below. As shown in each of these drawings, the mechanism of the film thickness monitor 7 is a base 10 supported by the support rod 8 described above.
And an arm 11 fixed parallel to the base 10
Between, has been built. In addition, this base 10
It consists of a plane square plate. The arm 11 is formed of a narrow rectangular plate, and is fixed at a center of one side of the base 10 via a plate-like stay 12 fixed in a right angle direction. The tip of the arm 11 reaches just below the center of the base 10.

The surface of the base 10 on the arm 11 side (hereinafter referred to as the
In the center of the “lower surface”, a cylindrical stay 1
3 is vertically implanted, and a motor 14 as a rotating mechanism is fixed to the tip thereof. The drive shaft 14a of the motor 14 includes a washer 15 and a disc 1
6, extends coaxially with the stay 13 to the tip of the arm 11, and is rotatably supported at the tip of the arm 11. The disk 16 is mounted on the drive shaft 1
Since it is integrally fixed to 4a, it rotates in a plane orthogonal to the drive shaft 14a by driving the motor 14.
The surface of the disk 16 on the side of the arm 11 (hereinafter referred to as the “lower surface”
), A large number of concentric track grooves 16a around the drive shaft 14a are formed at a constant pitch. In FIG. 3, the area where the track groove 16a is formed on the lower surface of the disk 16 is shaded.

Immediately below the lower surface of the disk 16, a large number of disk-shaped slit units 18 are installed so as to pass through the outside of the disk 16 with a slight gap left between the disk 16 and the lower surface of the disk 16. It is suspended and fixed by a rod-shaped stay 17. The slit unit 18 as a shielding member has a function of covering the lower surface of the disk 16 (the flat surface on the side of the diffusion source) to prevent the deposition material from adhering to the entire lower surface of the disk 16. Also,
The slit unit 18 has a plurality of slits S formed in a direction perpendicular to the radial direction and configured to be movable in the radial direction, uniformly in the circumferential direction. The slit S exposes only one of the track grooves 16 a formed on the lower surface of the disk 16 to the crucible 5, and forms a thin film of a deposition material diffused by the crucible 5 in the track groove 16 a. At the same time, the reflectance of the thin film thus formed in the track groove 16a is measured by the optical unit 19 installed on the arm 11. Hereinafter, a detailed configuration of the slit unit 18 will be described.
This will be described with reference to FIGS.

FIG. 5 is an exploded view of the slit unit 18. As shown in FIGS. 5 and 4, the slit unit 18 has a disk-shaped first slit member in which a large number of radiation grooves 20a are formed on a surface on the disk 16 side (hereinafter, referred to as an “upper surface”). 20, a large number of second slit members 21 slidably fitted in the respective radiation grooves 20a, and outer edges of the upper surface of the first slit members 20 to prevent the respective second slit members 21 from dropping out of the radiation grooves 20a. An annular holding frame 23 screwed in the vicinity, and an annular gear 24 fitted on the outer periphery of the first slit member 20 for slidingly driving each of the second slit members 21,
Be composed. Hereinafter, these components will be described.

The first slit member 20 as the first shielding member is fixed concentrically with the disk 16 by the above-mentioned rod-shaped stay 17. FIG. 6 shows a top view of the first slit member 20. As shown in FIG. 6, the first
The drive shaft 14 of the motor 14 is
The through hole 20b through which a rotatably penetrates is formed.
Each of the above-mentioned radiation grooves 20a is formed in this through hole 20b.
Are formed around the through-hole 20b at a constant angular interval so as to reach the outer edge of the first slit member 20. Each of the radiation grooves 20a has a rectangular cross-sectional shape, and is slightly wider than the second slit member 21 so that the second slit member 21 can slide therein.

The bottom of each radiation groove 20a has a radiation groove 2
A sub-slit 20c as a slide slit is formed over the entire length, leaving a small width (step) between both side walls of the first slit member 0a and the outer edge of the first slit member 20 and the through hole 20b. . The width of the sub-slit 20c is set to prevent the second slit member 21 from dropping.
The width is smaller than the width of the second slit member 21.

The second slit member 21 as a second shielding member is an elongated plate-like member having the above-mentioned slit S formed near one end thereof. The slit S is formed along the short direction of the second slit member 21 (the direction perpendicular to the radial direction of the disk 16), and the width thereof is set to each track of the disk 16 as shown in FIG. Groove 1
The width is almost the same as 6a. The length of the second slit member 21 is the same as the sum of the total length of the radiation groove 20a of the first slit member 20 and the width of the ring gear 24. Each of the second slit members 21 has one of the radiation grooves 20a with its end (hereinafter, referred to as “inner end”) in which the slit S is formed in the vicinity thereof facing the through hole 20b of the first slit member 20. It is set inside. Therefore, at a position where the inner end matches the inner surface of the through hole 20 b, the other end of the second slit member 21 (hereinafter, referred to as “outer end”) is moved from the outer edge of the first slit member 20 to the annular gear 24. Protrude by the width. In addition, the rear surface of the second slit member 21 (the surface facing the sub slit 20c) forms a certain angle (preferably an acute angle close to a right angle) with respect to the longitudinal direction of the second slit member 21. The ridges 21a are formed to project at a constant pitch. The total thickness of the second slit 21 including the height of the ridge 21a is the same as the depth of each radiation groove 20a so that the second slit member 21 is completely fitted into each radiation groove 20a. I have.

The holding frame 23 is formed in an annular shape having the same outer diameter as the first slit member 20, and is fixed to the upper surface of the first slit member 20 by four screws 22. The vertical section of the holding frame 23 is a rectangle that is wide in the radial direction of the holding frame 23 itself. For the purpose of preventing the second slit member 21 from falling off, the width of the holding frame 23 is desirably as wide as possible within a range that does not hinder the formation of the thin film via the slit S.

The annular gear 24 is fitted on the outer peripheral surface of the first slit member 20 so as to be rotatable with respect to the first slit member 20. Therefore, the inner diameter of the ring gear 24 is formed slightly larger than the outer edge of the first slit member 20. The prevention of the ring gear 24 from dropping toward the disk 16 is performed by the second slit members 21 positioned by the holding frame 23. Also,
This ring gear 24 is prevented from dropping to the arm 11 side as shown in FIG.
As shown in FIG. 5 and FIG. Each holding bracket 25 is a screw 28
The first slit member 20 is fixed to a surface of the first slit member 20 on the arm 11 side (hereinafter, referred to as a “lower surface”).
The ring-shaped gear 24 is prevented from falling off at the tip bent at a right angle according to the shape of.

The second slit member 21 of the ring gear 24
On the surface (hereinafter, referred to as “upper surface”) opposed to the second slit member 21, a plurality of feed grooves 24 a are formed.
It is formed at the same pitch as a. In addition, each feed groove 24a
Is at the same angle as the angle formed by each ridge 21a with respect to the longitudinal direction of the second member 21, and intersects the radial direction of the ring gear 24 itself. Therefore, the feed groove 24a is a spiral groove as a whole. Each of the feed grooves 24a fits with each of the ridges 21a of each of the second slit members 21. However, in order to avoid backlash with each of the ridges 21a due to rotation of the ring gear 24 itself, each of the ridges 21a is Is also wide.

On the outer peripheral surface of the ring gear 24, the gear 2
4b is cut. The gear 24b meshes with a pinion 27 that is driven to rotate by a motor 26 installed on the arm 11. Therefore, the motor 26 is connected to the pinion 2
7, the ring gear 24 meshing with the pinion 27 rotates around the first slit member 20 and the feed groove 24a of the ring gear 24
The second slit member 21 in which a is fitted is slid in the radial direction of the first slit member 20. As a result, the slit S moves in the radial direction of the disk 16. The relative position of all the second slit members 21 with respect to the ring gear 24 (that is, the ridge 21 with respect to the feed groove 24a)
a) is all slits S with respect to the center of rotation of the disk 16 (ie, the drive shaft 14a of the motor 14).
Are set to be the same distance from each other. The motor 26, the pinion 27, and the ring gear 24 constitute a moving mechanism.

A specific one of the second slit members 21 (hereinafter, referred to as a "monitor second slit member 21 '")
Are located above the center line of the arm 11. The optical unit 19 is provided on the center line of the arm 11 in parallel with the second slit member 21 'for monitoring. The internal configuration of the optical unit 19 is shown in FIG.
Is shown in an enlarged perspective view. In this enlarged perspective view, in addition to the optical unit 19, the arm 11, the drive shaft 14a of the motor 14, the disk 16, and the second slit member 21 'for monitoring are illustrated. The illustration of other members is omitted.

As shown in FIG. 9, the optical unit 19
Pulleys 30 and 31 are attached to the inner and outer ends of the bottom surface 19a of the optical unit 19, respectively, so as to be rotatable around an axis oriented in the short direction of the optical unit 19 in parallel with the disk 16. One of these pulleys 31 is rotationally driven by a motor 33 via a belt 32. A belt 34 extends between the pulleys 30 and 31. Accordingly, the belt 34 can be moved from one pulley 30 to the other pulley 31 or in the opposite direction by the motor 33 rotating the pulley 31 in a desired direction.

A photoreflector unit 35 slidable only in the longitudinal direction of the optical unit 19 (in the radial direction of the disk 16) is fixed to the belt 34. The photoreflector unit 35 includes a light emitting diode 351, a collimator lens 352 that emits light emitted from the light emitting diode 351 toward the disk 16, a condenser lens 353 that collects reflected light from the disk 16, and a condenser lens. Phototransistor 354 that receives light condensed by 353
Built-in.

The photoreflector unit 35 is controlled by a motor 33 so as to move together with the second slit plate 21 'for monitoring and to always be located below the slit S (second slit). That is, the motor 33, the two pulleys 30, 31, and the belt 34 constitute a moving mechanism. Therefore, the photoreflector unit 35 is connected to the track groove 16a located on the slit S through the slit S, and
Light is irradiated by the collimator lens 51 and the collimator lens 352, and the reflected light from the track groove 16a is received by the condenser lens 353 and the phototransistor 354. In other words, the photoreflector unit is movable in the radial direction of the disk, facing the lower surface of the disk 16 via the slit S of the second slit plate 21 'for monitoring.

The monitor second slit member 21 '
Is always covered by the arm 11 and the optical unit 19, so that no thin film is formed in the track groove 16a of the disk 16 through the slit S, and the photoreflector unit 35 Only the reflected light measurement is performed. Therefore, the slit S (the second slit) formed in the second
May be larger than the slit S (first slit) formed in the other second slit member 21. A sub-slit 20 formed in the radiation groove 20a in which the second monitoring slit member 21 'is fitted.
If the deposition material does not adhere to any of the track grooves 16a via the second c, this second monitoring slit member 21 '
It may not be necessary.

Next, the motors 14, 26, 3
And a control circuit provided outside the evaporation tank 1 for controlling the photoreflector unit 35 and calculating the thickness of the thin film formed on the surface of the lens L based on the amount of reflected light received by the phototransistor 354. 40
Will be described with reference to FIG. As shown in FIG.
The control circuit 40 controls the motors 14, 26, 33, the light emitting diode 351 in the photoreflector unit 35, the phototransistor 354, and the resistance heater 5 in the crucible 5.
a (only one is shown in FIG. 10), main switch S1,
Reset switch S2, shift switch S3, and
Each is connected to the disk device 46.

When the main switch S1 is turned on, the control circuit 40 controls the disk device 4 serving as a program storage medium.
By executing the program stored in 6,
Motor control unit 41, reflectance measurement unit 42, film thickness calculation unit 4
3. The respective functions of the comparison unit 44 and the vapor deposition control unit 45 are respectively generated therein.

A motor control unit 41, which is a part of the rotating mechanism and the moving mechanism, constantly rotates the motor 14 to rotate the disk 16 at a constant speed in a constant direction at a constant speed. Further, when the reset switch S2 is turned on, the motor control unit 41 synchronously rotates the motor 26 and the motor 33 to move the slit S of each second slit member 21 to a position directly below the innermost track groove 16a. At the same time, the photo reflector unit 35 is moved directly below the slit S of the second monitoring slit member 21 '. Further, the motor control unit 41
When the shift switch S3 is turned on, the motor 26 and the motor 33 are rotated synchronously so that each of the second slit members 2
The one slit S is moved directly below the track groove 16a on the outer side, and the photoreflector unit 35 is moved right below the slit S of the second monitoring slit member 21 '.

The reflectivity measuring section 42 always causes the light emitting diode 351 to emit light and the phototransistor 3
54 monitors the amount of reflected light received. Then, based on the amount of reflected light, the reflectance of the bottom surface of the track groove 16a (the thin film formed on the surface) facing the phototransistor 354 via the slit S is calculated. The reflectance calculated by the reflectance measuring unit 42 in this way is notified to the film thickness calculating unit 43.

The film thickness calculating unit 43 calculates the film thickness of the thin film in the track groove 16a by performing a predetermined operation based on the reflectance notified from the reflectance measuring unit 42 (monitoring film thickness). The film thickness of the thin film on the lens L set in the rack 6 is calculated by integrating a predetermined proportionality constant with the calculated film thickness (corresponding to a substrate film thickness calculating unit). ). The above-mentioned proportionality constant is based on the film thickness of the thin film formed on the lens L when vapor deposition is actually performed in the vapor deposition chamber 1 and the reflectance of the thin film formed in any of the track grooves 16a. Is determined experimentally in advance. The value of the film thickness on the lens L calculated by the film thickness calculation unit 43 is notified to the comparison unit 44.

The comparing unit 44 compares the notified film thickness value with a target film thickness value arbitrarily set by the operator, and when the notified film thickness value reaches the target film thickness.
This is notified to the vapor deposition control unit 45.

Before the notification from the comparing section 44 (immediately after the start-up or after the reset switch S2 is turned on), the vapor deposition control section 45 performs the operation.
In, power is supplied to the resistance heating element 5a in any of the crucibles 5, but upon notification from the comparison unit 44, the power supplied to the resistance heating element 5a is cut off. (Operations of Vacuum Deposition Apparatus and Film Thickness Monitor) Next, operations of the vacuum evaporation apparatus and the film thickness monitor configured as described above will be described. [Formation of First Layer Thin Film] First, prior to the vapor deposition step, the operator removes top plate 1 a from vapor deposition chamber 1, fits lens L into each through hole formed in holder 6, and sets each crucible 5. A predetermined thin film forming substance is set in the inside as a vapor deposition material. Further, the desired target film thickness is determined by the comparing unit 4 of the control circuit 40.
Set to 4.

When the above preparation is completed, the operator seals the vapor deposition vessel 1 with the top plate 1a, opens the valve 3, and sucks the air in the vapor deposition vessel 1 by the suction pump 4. Then, when the pressure in the evaporation chamber 1 is reduced to about 1 × 10 ⁻⁵ (Torr) by the suction of the suction pump 4, the operator turns on the main switch S1 and the reset switch S2. Then, the slit S of each second slit member 21 is moved by the motor control unit 41 to just below the innermost track groove 16 a on the lower surface of the disk 16, and the photo-reflector unit 35 in the optical unit 19 is moved to the second position for monitoring. It is moved just below the slit S of the two slit member 21 '. At the same time, the motor control unit 4
1, the disk 16 is rotated at a high speed, and power is supplied by the vapor deposition control unit 45 to the resistance heating element 5a in any one of the crucibles 5 in which the first layer vapor deposition material is set.

When the temperature in the crucible 5 rises due to the power supply to the resistance heating element 5a, the vapor deposition material set in the crucible 5 evaporates, and its molecules are diffused into the vaporization vessel 1. The molecules of the vapor deposition material diffused as described above are attached and condensed on each lens L set in the holder 6 at a predetermined probability to form a thin film, and through each slit S,
A thin film is also formed in the innermost track groove 16a on the lower surface of the disk 16.

At this time, since the disk 16 is rotating at a high speed, a ring-shaped thin film having a uniform thickness is formed in the track groove 16a. Further, since the growth rate of the thin film formed on each lens L set in the holder 6 and the growth rate of the thin film formed in the track groove 16a are respectively constant, the thickness ratio of the two thin films is constant. Is kept.

During such a deposition step, the track groove 16 is formed.
The reflectance of the thin film formed in a is measured by the photoreflector unit 35 and the reflectance measuring unit 42. Then, the film thickness calculating unit 43 calculates the film thickness of the thin film in the track groove 16a based on the measured reflectance of the thin film, and adds a predetermined proportional constant to the calculated film thickness of the thin film in the track groove 16a. By the integration, the thickness of the thin film on the lens L is calculated.

Since the reflectance has a periodic function relationship with the thickness of the thin film, the range of the thickness of the thin film in the track groove 16a that can be calculated based on the reflectance is not so wide. However, as described above, since the ratio of the thickness of the thin film in the track groove 16a to the thickness of the thin film on each lens L is extremely low, the thickness of the thin film on the lens L can be calculated based on the reflectance. The range of film thickness is very wide.

The film thickness of the thin film on the lens L calculated by the film thickness calculating section 43 is compared with the target film thickness by the comparing section 44. When the calculated film thickness reaches the target film thickness,
The vapor deposition control unit 45 stops supplying power to the resistance heating element 5a in the crucible 5, and ends the first-layer thin film forming process. [Formation of Second and Subsequent Thin Films] When forming the second and subsequent thin films on the lens L set in the holder 6, the operator turns on the shift switch S3. Then, each second slit member 2 is controlled by the motor control unit 41.
One slit S is moved to just below the outer track groove 16 a on the lower surface of the disk 16, and the photo reflector unit 35 in the optical unit 19 is moved to just below the slit S of the second monitoring slit member 21 ′. . At the same time, power is supplied by the vapor deposition control unit 45 to the resistance heating element 5a in any one of the crucibles 5 in which the vapor deposition material of the layer is set.

Then, in the same manner as in the case of the first layer described above, a thin film is formed in the track groove 16a where the slit S is located immediately below (one outer track groove 16a). The thickness of the lens L set in the holder 6 is calculated based on the reflectance of the thin film in the inside. Then, when this film thickness reaches the target film thickness, the thin film forming step of that layer is completed.

As a result of repeating the above thin film forming steps, when the outermost layer thin film forming step is completed, the operator stops the suction pump 4 and introduces outside air from the valve 3 into the vapor deposition vessel 1. The plate 1a is detached from the evaporation pot 1. [Replacement of Disk] As a result of repeating the thin film formation as described above, if a thin film is formed in all the track grooves 16a on the lower surface of the disk 16, the operator replaces the disk 16 with a new one. The reset switch S2 is turned on. Then, the slit S of each second slit member 21 is
Again, the disk moves to the position immediately below the innermost track groove 16a on the lower surface of the disk 16 and the photoreflector unit 3
5 moves directly below the slit S of the second slit member for monitoring 21 '.

As described above, according to the film thickness monitor of this embodiment, the thin film for monitoring (the thin film formed in the track groove 16a) is formed on the lower surface of the disk 16 which rotates at a high speed.
Is formed, the thickness of the thin film for monitoring becomes uniform, which contributes to accurate film thickness monitoring. Further, since the monitoring thin film formed on the lower surface of the disk 16 is measured by the photoreflector unit 35 movable in the radial direction of the disk 16, the width of the monitoring thin film does not need to be very wide.

Therefore, since a large number of monitoring thin films can be formed on the lower surface of one disk 16, the number of thin films that can be monitored on one disk 16 can be reduced without increasing the scale of the apparatus. You can do much. The number of layers whose film thickness can be monitored on one disk 16 can be, for example, about 100 layers. As described above, if the number of thin films whose thickness can be monitored is increased, the number of replacement operations of the disk 16 can be extremely small. Further, since the film thickness monitoring can be immediately resumed only by replacing the disk 16, the labor required for replacement can be reduced. Further, the size of the entire film thickness monitor 7 can be small, and the optical path length required for reflectance measurement can be short, so that noise can be prevented from being mixed in the measurement.

If the disk 16 is made of metal or glass, the disk 16 can be reused only by shaving off the thin film formed in each track groove 16a of the disk 16.

[0061]

As described above, according to the film thickness monitoring apparatus of the present invention, a very thin ring-shaped monitoring thin film can be formed on a single disk with a uniform film thickness.
It is possible to accurately monitor the thickness of a large number of thin films using one disk.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a vacuum deposition apparatus incorporating a film thickness monitoring apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the film thickness monitor of FIG. 1;

FIG. 3 is a plan view of the disk shown in FIG. 2;

FIG. 4 is a perspective view showing a state in which the thin film monitoring device is viewed from obliquely below.

FIG. 5 is an exploded view of the slit unit of FIG. 4;

FIG. 6 is a plan view of a first slit member of FIG. 5;

FIG. 7 is a partially enlarged perspective view of a first slit member.

FIG. 8 is a partial perspective view of the second slit member of FIG. 5;

FIG. 9 is a perspective view of the optical unit of FIG. 2;

FIG. 10 is a block diagram showing a control circuit.

FIG. 11 is a cross-sectional view of a vacuum deposition apparatus incorporating a conventional film thickness monitoring apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Deposition pot 6 Holder 7 Film thickness monitor device 14, 26 Motor 18 Slit unit 19 Optical unit 20 First slit member 20a Radiation groove 20c Secondary slit 21 Second slit member 24 Ring gear 35 Photoreflector unit L Lens S Slit

Claims (9)

[Claims] An apparatus for monitoring the thickness of a thin film in a thin film forming apparatus for forming a thin film by attaching a material diffused from a diffusion source to a surface of a substrate disposed in a vacuum chamber. And a disk rotatably installed in a plane orthogonal to the center axis of the vacuum chamber, a rotation mechanism for rotating the disk, and a flat surface on the diffusion source side of the disk, A shielding member formed along a direction orthogonal to the radial direction of the disk and having a slit configured to be movable in the radial direction of the disk; and a diameter of the disk facing the plane of the disk on the diffusion source side. And irradiating light to a thin film formed on the plane of the disk by the material passing through the slit of the shielding member. A thin film monitor device comprising: a photo reflector for receiving light reflected by the thin film; and a moving mechanism for moving the slit and the photo reflector so as to be at the same distance from a center axis of the disk. . 2. A film thickness monitor for monitoring the thickness of a thin film in a thin film forming apparatus for forming a thin film by attaching a material diffused from a diffusion source to a surface of a substrate disposed in a vacuum chamber. And a disk rotatably installed in a plane orthogonal to the center axis of the vacuum chamber, a rotation mechanism for rotating the disk, and a flat surface on the diffusion source side of the disk, A shielding member formed along a direction orthogonal to the radial direction of the disk and having at least two slits configured to be movable in the radial direction of the disk; and a disk formed by the material passing through the first slit. A photoreflector that irradiates the thin film formed on the plane with light through the second slit and receives reflected light; The slit film monitoring apparatus characterized by comprising from the central axis and a moving mechanism that moves so that the distance of the disk. 3. A film thickness monitor for monitoring a film thickness of a thin film in a thin film forming apparatus for forming a thin film by attaching a material diffused from a diffusion source to a surface of a substrate disposed in a vacuum chamber. And a disk rotatably installed in a plane orthogonal to the center axis of the vacuum chamber, a rotation mechanism for rotating the disk, and a flat surface on the diffusion source side of the disk, A shielding member formed along a direction orthogonal to the radial direction of the disk and having at least two slits configured to be movable in the radial direction of the disk; and the opposite side to the disk with the shielding member interposed therebetween. The thin film formed on the plane of the disk by the material passed through the first slit is provided so as to be movable in the radial direction of the disk. A photoreflector that irradiates light through the second slit and receives the reflected light, and a moving mechanism that moves each of the slits and the photoreflector so as to be at the same distance from a center axis of the disk. And a thin film monitor device. 4. The shielding member has a first shielding member having a slide slit extending in a radial direction of the disk, and the slit is formed so as to be slidable with respect to the slide slit. The thin-film monitor device according to any one of claims 1 to 3, further comprising a second shielding member. 5. The apparatus according to claim 1, further comprising a reflectivity measuring unit for measuring a reflectivity of a thin film formed on said disk based on an amount of reflected light received by said photo reflector. The thin-film monitor device according to any one of the above. 6. A monitor film thickness calculation unit for calculating a film thickness of a thin film formed on the disk based on the reflectance measured by the reflectance measurement unit. Item 6. A thin film monitor according to item 5. 7. A substrate thickness calculating section for calculating a thickness of a thin film formed on the substrate surface based on the film thickness calculated by the monitoring film thickness calculating section. The thin film monitor according to claim 6. 8. A film thickness monitor according to claim 7, further comprising a comparing section for judging whether or not the film thickness calculated by said substrate film thickness calculating means has reached a target film thickness. . 9. A control unit for stopping diffusion of the material from the diffusion source when the comparison unit determines that the film thickness of the thin film has reached a target film thickness. Item 10. A film thickness monitor according to Item 8.