JPH10140340A - Sputtering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute continuous film formation by a granular target without breaking the vacuum in a chamber. SOLUTION: Plural rings 14 are piled on a magnetron cathode 11, a granular target 15 is filled into the rings 14, and sputtering is executed. Every time the sputtering finishes, the ring is taken out from the upper side, and the used target within the ring is dropped into a clean storage equipment 3. Since the new surface of the target within the ring 14 at the lower side exposes, continuous film formation can be executed without breaking the vacuum in the chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus used for producing an optical thin film such as an antireflection film or a half mirror used for an optical component.

[0002]

2. Description of the Related Art Excellent film adhesion without heating a substrate
Benefits, such as the ability to be automated and ease of automation?
Et al. Technology for forming optical thin films by sputtering
Is being considered. In this sputtering method,
The get material is SiO 2 as a low refractive index material._TwoOr S
iO_TwoAnd other substances, Ti as high refractive index material
O _Two, Ta_TwoO_Five, ZrO_Two, In_TwoO_Three, SnO_Two,
Nb_TwoO_FiveOr Yb_TwoO_ThreeOr a mixture of these
It is used. Using these, high transparent substrates
Alternating refractive index material and low refractive index material by sputtering
To obtain, for example, an anti-reflection film
Can be. These target materials are usually bonded to a copper plate.
Plated material is used. Continuous spatter
For example, Japanese Patent Application Laid-Open No. 5-39567 discloses a
As shown in Japanese Patent Publication No.
And the position facing the substrate.
Position to flip 180 degrees from the position
The chamber can be replaced by using
Enables replacement without breaking vacuum of (film forming equipment)
I have.

[0003] By the way, the present inventor, when sputtering is performed using MgF ₂ as a plate material while maintaining the vacuum in such a chamber without breaking, the deposited MgF ₂ is formed.
_It was found that it was difficult to use it as an optical thin film for optical components because visible light was absorbed in the thin film of No. ₂ . Also,
At the same time, it was found that when MgF ₂ was used as a target material as granules, the formed MgF ₂ thin film suppressed absorption of visible light.

[0004]

However, when a granular material is used as the target material, Japanese Unexamined Patent Application Publication No. 5-395
The position changing means for reversing the target material described in No. 67 cannot be employed. This is because continuous sputtering cannot be performed because the granules fall from the disposition position when the target material is inverted. Further, since the erosion occurs in the granule target material used once, fluorine atoms on the surface of the material are lost at a portion to be sputtered, and the target material is deteriorated. Therefore, when sputtering is performed using the same material again, light absorption occurs and the film becomes inhomogeneous, and stable optical characteristics cannot be obtained. From the above, in order to expose the unused material, it is necessary to break the vacuum of the chamber when supplying the granular target material. Therefore, evacuation time is required again, and the productivity is reduced.

The present invention has been made in view of such a conventional problem. Even in sputtering using a granular material as a target, an unused material can be exposed without breaking the vacuum of the chamber. An object of the present invention is to provide a sputtering apparatus that can form a new film and does not cause a change in optical characteristics due to deterioration of a material.

[0006]

In order to achieve the above object, an object of the present invention is to provide an apparatus for forming a thin film on a substrate by sputtering a granular target provided in a chamber. It is characterized in that a means for removing the used portion to expose a new surface and for holding the removed used portion in the chamber is provided.

[0007] In this apparatus, since a used portion of the target used for sputtering is removed to expose a new surface of the target, sputtering can be performed using a new target. Can be prevented. Further, since the exposure of the new target and the holding of the used portion of the removed target are performed in the chamber, continuous film formation can be performed without breaking the vacuum of the chamber.

According to a second aspect of the present invention, a closed chamber to which a substrate is intermittently supplied, an electrode provided in the chamber, a plurality of rings stacked on the electrode, and a ring are formed. And a take-out means for sequentially taking out the granulated target filled in the space, the stacked rings together with the internal target from the upper layer side, and a storage provided in the chamber for accommodating the ring taken out by the take-out means. And a storage.

[0009] In this apparatus, since the removing means sequentially removes the ring from the upper side, the used portion of the target used for sputtering can be removed together with the ring, and can be stored in the storage.

Further, when the ring is taken out, a new target in the lower ring is exposed. Therefore, continuous film formation can be performed without breaking the vacuum of the chamber.

According to a third aspect of the present invention, there is provided a closed chamber to which a substrate is intermittently supplied, an electrode provided in the chamber, a ring placed on the electrode, and a ring in the chamber. A moving means for taking out from the electrode and returning it to the electrode, a supply means for filling the ring with a granular target in the chamber, and a storage provided on the moving path of the ring by the moving means for accommodating the target in the ring. And characterized in that:

In this apparatus, the moving means operates to remove and return the ring from above the electrode, and the target in the ring used for sputtering can be stored in the storage by removing the ring. The supply means fills a new target in the ring returned on the electrode. Therefore, continuous film formation can be performed without breaking the vacuum of the chamber.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) Figs. 1 to 4 show Embodiment 1 of the present invention. Fig. 1 is a cross-sectional view of a continuous RF sputtering apparatus.
FIG. 2 is a cross-sectional view near the target material, and FIG. 3 is a partial plan view of the apparatus. In this apparatus, a thin film is formed by sputtering while the substrate 7 is intermittently transferred in the direction of arrow A. A transfer toy 5 is provided above a chamber 4 in which a film forming chamber is formed. The transporting toy 5 intermittently moves in the direction of arrow A while supporting the plurality of substrates 7.

In the moving path of the transporter 5, gate valves 6 and 8 for partitioning between the chamber 4 and the chamber lid 9 are arranged. These gate valves 6, 8
Are performed alternately, the gate valve 8 on the downstream side in the direction of arrow A is opened, and the transport gate 5 is moved by one substrate 7, and then the gate valve 6 on the upstream side is opened. The next substrate 7 is carried into the upper part of the chamber 4.

A partition plate 10 is laid inside the chamber 4, and a magnetron cathode 11 as an electrode is mounted on the partition plate 10.
The target member 1 is laminated on the upper side via a plate 12.

As shown in FIG. 2, the target member 1 has a copper petri dish 13 placed on a plate 12, a plurality of rings 14 laminated on the petri dish 13, and a space formed by these. Granular target 1
And 5. In this embodiment, the ring 14 is a copper ring having a height of 3 mm and a diameter of 15 inches, and ten such rings 14 are stacked on a petri dish 13.
Using the gF ₂ granules. Note that the target 15 is evened out so that the surface becomes flat.

Each of the rings 14 is positioned by two positioning guides 16 erected from the petri dish 13 so that the rings 14 are stacked without misalignment. A hook receiver 17 is provided on an outer surface of each of the rings 14 to be engaged with a hook 21 of a take-out means 20, which will be described later.

A storage 3 is formed in a portion of the partition plate 10 adjacent to the target member 1. Storage 3
Is formed by recessing a partition plate 10 in the vicinity of a portion where the target member 1 is provided as shown in FIG. I have. The storage 3 houses the ring 14 and has a larger volume than the ring 14.

Further, a take-out means 20 is arranged at a position close to the target member 1 and the storage 3. The take-out means 20 includes an air cylinder 22 arranged below the chamber 4 as shown in FIG. 1, a vertically movable shaft 23 inserted into the chamber 4 from the air cylinder 22,
A vacuum motor 24 attached to the upper end of the shaft 23 and provided at a position close to the ring 14 of the target member 1. A hook 21 is attached to the vacuum motor 24, and the hook 21 is attached to the outer surface of the ring 14. Hook holder 17
Engage with. The shaft 23 is engaged with two guide rods 25 suspended from the bottom surface of the chamber 4. When the air cylinder 22 operates, the shaft 23 descends by one thickness (3 mm) of one ring 14. This lowering causes the uppermost ring 14 to sequentially face the lowermost ring 14. In FIG. 1, reference numeral 18 denotes a gas introduction pipe attached to a side surface of the chamber 1, and reference numeral 19 denotes a high-frequency power supply provided outside the chamber 4 for supplying power to the magnetron cathode 11.

Next, the film formation according to this embodiment will be described. The film is formed by introducing Ar into the chamber 4 from the gas introduction pipe 18.
After the gas is introduced, 500 W of electric power is supplied from the high-frequency power supply 19 to the target member 1 set on the magnetron cathode 11 via the plate 12 to generate plasma, thereby generating MgF ₂ granules (target) in the target member 1. By sputtering 15)
A film is formed on the substrate 7.

After forming a film of 130 nm on a glass substrate 7 having a diameter of 50 mm and a refractive index of 1.75, the reduced target 1
Remove 5 That is, as shown in FIG. 3, the hook 21 provided on the vacuum motor 24 at the top of the shaft 23 of the air cylinder 22 starts rotating from the origin position by the rotation accompanying the operation of the vacuum motor 24, and the uppermost ring 14 is fitted with a hook 17. When the hook 21 rotates 180 ° in the direction of arrow B from the origin position, the uppermost ring 14 and the used material 15 on the uppermost ring 14 are dropped from the slope 42 into the storage 3.

As described above, the engagement between the hook 21 and the ring 14 provided on the vacuum motor 24 and the discharging operation of the ring enable the new material in the lower ring 14 of the next stage without exposing the chamber 4 to the atmosphere. Can be exposed, and the MgF ₂ film can be formed on a large number of substrates 7 continuously transferred on the chamber 4 by the new material.

The hook 21 further rotates and returns to the home position. On the other hand, the shaft 23 supporting the vacuum motor 24 is provided with two guides 2 provided at the bottom of the chamber 4.
5 is moved down by 3 mm at a time, and is lowered by one ring to reach the lower ring 14 of the next stage. Then, the target 15 is converted into a new material by fitting the hooks 17 provided on each of the ten rings 14 and sequentially dropping the rings 14 into the storage 3.

In such an embodiment, the target 1
Since the material of No. 5 is a granule having low thermal conductivity, the temperature is the same even if the height of the material is different, so that the deposition rate does not change regardless of which of the ten rings 14 is at the top. Does not occur.

FIG. 4 shows that after forming nine batches, the tenth batch has an optical thickness of 13 on the substrate 7 having a refractive index of 1.75.
It is an absorption characteristic of a film formed with a thickness of 0 nm. The absorption is 0.5% or less in the visible region (wavelength 400 to 700 nm), which is a level having no optical problem.

(Embodiment 2) FIGS. 5 to 9 show Embodiment 2 of the present invention. In this embodiment, the substrate 7
This shows application to a multi-layer RF sputtering apparatus for forming a multi-layer film. By providing a partition wall 31 in the chamber 4, two types of target members 32 and 33 are arranged in the chamber 4 in a partitioned state. .

Each of the target members 32 and 33 is
It is laminated via a plate 12 on a magnetron cathode 11 mounted thereon. As shown in FIG. 6, each of the target members 32 and 33 is a plate 1
A petri dish 34 made of quartz and a petri dish 3
It is composed of a single quartz ring 35 stacked on 4 and a granular target 36 filled in the space formed by them. As shown in FIG. 7, a chuck 37 protrudes from the outer surface of the ring 35.
In this embodiment, the Petri dish 34 has a depth of 5 mm, a rectangular frame with a bottom of 5 inches on each side, and a ring 35 having a height of 5 m.
m, 5 inches on each side. Further, SiO ₂ granules are used as the target 36 of the target member 32, and Z ₂ is used as the target 36 of the target member 33.
rO ₂ granules are used.

The storages 3 are respectively formed in the vicinity of the positions where the target members 32 and 33 are provided by recessing the partition plate 10, and the slopes 2 are formed in the respective storages 3. I have.

Each of the target members 32, 3
For 3, a supply means 40 for supplying the granular material is arranged. As shown in FIG. 7, the supply means 40 is connected to a transfer motor 41 disposed outside the chamber 4, a transfer arm 42 inserted into the chamber 4 from the transfer motor 41, and a tip of the transfer arm 42. Feeder 4
3 is provided. The transfer arm 42 advances and retreats along the guide 44 to move the feeder 43 forward and backward. The movement of the feeder 43 is guided by a rail plate 45 provided on the lower surface side. The feeder 43 has a nozzle 46 extending in the direction of the ring 35, and supplies the granular material from the nozzle 46 to the target members 32 and 33 by vibrating.

Further, a vacuum motor 46 is arranged at a position close to each of the target members 32 and 33, and the vacuum motor 46 is provided with a chuck 47 which is detachably engaged with the chuck 37 of the ring 35. Have been. The vacuum motor 46, the chuck 47, and the chuck 37 on the side of the ring 35 constitute moving means for reciprocating the ring 35 between the magnetron cathode 11 and the storage 3. In order to position the target members 32 and 33,
The plate 12 is provided with a positioning guide 48.

The film is formed by introducing an Ar gas into the chamber 4 through a gas introducing pipe 18 and then depositing the magnetron cathode 11
The high-frequency power supply 19 is connected to the target member 33 set above.
To 500 W, and generate plasma to sputter ZrO ₂ granules to form a film on the substrate 7. Similarly, when a film is formed by the target member 32, similarly, after introducing Ar gas from the gas introduction pipe 18, 450 W of power is supplied from the high frequency power supply 19 to the target member 32 set on the magnetron cathode 11 to generate plasma. Then, the SiO ₂ granules are sputtered to form a film on the substrate 7.

In this embodiment, four multilayer antireflection films are formed on a glass substrate 7 having a diameter of 50 mm and a refractive index of 1.52. At this time, every time one layer is formed, when the other material is formed, for example, during the film formation of the SiO ₂ granules, the material surface of the reduced ZrO ₂ granules is removed.

That is, the chuck 47 provided on the vacuum motor 46 installed near the target member 33
The rotation starts from the clockwise origin position and engages with the chuck 37 provided on the ring 35 at the clamping position. As a result, the ring 35 moves the chuck 47 180 ° from the origin position.
While rotating, it passes over the slope 2 and moves onto the storage 3. Thereby, only the granules used for film formation are excluded. Thereafter, the chuck 47 rotates in the counterclockwise direction, the ring 35 returns to the holding position, and contacts the positioning guide 48 implanted on the plate. At this time, the holding and the engagement are released, and the original position is maintained.

Next, since the feeder 43 of the supply means 40 provided in the vicinity of the target 33 is connected by the transport motor 41 and the transport arm 42, the feeder 43 is sent out on the rail plate 45 along the guide 42, and The nozzle 46 moves from the position D indicated by a chain line in FIG. Then, the feeder 43 vibrates and starts supplying the granular material to the ring 35. The feeder 43 that sends out the granular material by vibration returns to the origin after the material is supplied from E to D. Similarly, the material is also converted to the target member 32 by a material removing device (not shown) and a supply unit that sends out the SiO ₂ granular material.

As a result, a stable film-forming rate can be obtained, and the material can be supplied without exposing the inside of the chamber 4 to the atmosphere. Can be. Therefore, as compared with the first embodiment, it is possible to form a film with a continuous batch number. The absorption characteristics of the first batch and the tenth batch after the start of the multilayer film are shown in FIGS. The absorption is 0.3% or less in the visible region (wavelength 400 to 700 nm), which is a level having no optical problem.

(Third Embodiment) FIGS. 10 and 11 show a third embodiment. The difference from the second embodiment is that two vacuum motors 46 are stacked. A chuck 47 is attached, and a metal (for example, stainless steel) fan-shaped plate 51 is attached to the lower vacuum motor 46. That is, the lower vacuum motor 46 can move independently of the hook 47 at the same height as the ring lower end 52 corresponding to the boundary surface between the quartz petri dish 34 and the quartz ring 35 of the second embodiment. 180 °
Is provided with a plate 51 having a fan shape and a thickness of 0.5 mm.

In the third embodiment, each ridge of the outer peripheral surface at the contact portion between the petri dish 34 and the ring 35 is chamfered, and a wedge shape is formed on the outer periphery of the boundary surface by the chamfered portion. I have. The lower vacuum motor 46 is actuated to rotate the plate 51, insert the plate 51 from the wedge-shaped portion, lift the ring and the granules 36 in the ring 35, and make the used portion and the unused portion of the material exactly divided. Then, the upper vacuum motor 46 is operated to hold the hook 37 by the chuck 47, and then the plate 51 and the chuck 47 are simultaneously rotated and carried to the upper part of the storage 3. After the plate 51 is located at the upper part of the storage 3, the material of the used part is dropped into the storage 3 at one time as the plate 51 returns to the origin before the chuck 47. Thereafter, when the chuck 47 returns to the holding position and the ring 35 hits the positioning guide 48, the holding and the engagement are released,
Retained in its original position. In the same manner as in the second embodiment, a material is supplied, and a film can be formed with a new material. In addition,
The thickness of the plate 51 is preferably about 0.2 to 0.5 mm.

COMPARATIVE EXAMPLE 1 In a continuous binary RF sputtering apparatus having two targets as shown in FIG. 12, granules of MgF ₂ and ZrO ₂ were each deposited at a depth of 5 m.
m, formed flat on a rectangular quartz petri dish with a bottom of 5 inches on each side to obtain targets 61 and 62. Then, a multilayer antireflection film of four layers is formed on the glass substrate 7 having a diameter of 50 mm and a refractive index of 1.52.

At this time, as shown in FIG. 13, the reduced target materials 61 'and 62' were used as they were in two layers. For each target used, the rate of the second layer was slower than that of the first layer, and the refractive index of ZrO ₂ was reduced from 2.0 to 1.98. In the next stage substrate, the film forming speed and the refractive index further changed. Further, FIG. 14 shows the measurement results of the absorption characteristics of the four-layered multilayer antireflection film of the first batch represented by the characteristic curve F and the second batch represented by the characteristic curve G. The absorption in the visible region is 0.5%. Compared to the following films of the first batch, the films of the second batch have an increased absorption rate of 4% or more in the visible region. Therefore, there is a problem in productivity because variation occurs in quality.

(Comparative Example 2) A continuous R as shown in FIG.
In an F sputtering apparatus, AlF ₃ granules are formed flat on a circular quartz petri dish with a depth of 5 mm and a diameter of 5 inches and having a bottom, and the target 63 is obtained. Then, after forming a film of 130 nm on a glass substrate 7 having a diameter of 50 mm,
The chamber 4 was leaked, replaced with a new material together with the petri dish in the atmosphere, evacuated again, and then subjected to sputtering. However, as a result of the time required for the leak in the chamber 4, replacement of the petri dish, and evacuation, the film forming tact was increased. For this reason, the merit of the continuous type has disappeared.

[0041]

According to the first aspect of the present invention, a used portion of a target used for sputtering is removed in a chamber,
Since the new surface of the target is exposed, the tact time for continuous film formation can be reduced, and a film having uniform quality and stable characteristics can be formed. According to the second aspect of the present invention, since the rings in the stacked state are sequentially taken out from the upper side, the used portion of the target used for sputtering can be removed together with the ring to expose a new surface of the target. According to the third aspect of the present invention, the target used for sputtering is stored in a storage by removing the ring from the electrode, and the ring is returned to the electrode, so that a new target can be filled without breaking the vacuum in the chamber. In addition, continuous film formation is possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view of the vicinity of a target member according to the first embodiment.

FIG. 3 is a plan view of the first embodiment.

FIG. 4 is an absorption characteristic diagram of a film formed according to the first embodiment.

FIG. 5 is a sectional view of the second embodiment.

FIG. 6 is a cross-sectional view of the vicinity of a target member according to the second embodiment.

FIG. 7 is a plan view of the second embodiment.

FIG. 8 is an absorption characteristic diagram formed according to the second embodiment.

FIG. 9 is an absorption characteristic diagram formed according to the second embodiment.

FIG. 10 is a sectional view of a main part of a third embodiment.

FIG. 11 is a plan view of a main part of the third embodiment.

FIG. 12 is a sectional view of Comparative Example 1.

FIG. 13 is a cross-sectional view of a target of Comparative Example 1.

FIG. 14 is an absorption characteristic diagram of a film formed according to Comparative Example 1.

FIG. 15 is a sectional view of Comparative Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Target member 3 Storage 4 Chamber 7 Substrate 20 Conversion means 21 Vacuum motor

Continued on the front page (72) Inventor Noriaki Mitamura 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industrial Co., Ltd. (72) Inventor Toshiaki Shimizu 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Industry Co., Ltd.

Claims (3)

[Claims] In an apparatus for forming a thin film on a substrate by sputtering a granular target provided in a chamber, a used portion of the target used for sputtering is removed to expose a new surface, and the removed target is used. A sputtering apparatus, comprising: means for retaining a part in a chamber. 2. A closed chamber to which substrates are intermittently supplied, electrodes provided in the chamber, a plurality of rings stacked on the electrodes, and a space formed by the rings. And a take-out means for taking out the stacked rings together with the internal targets from the upper layer side together with the internal targets, and a storage provided in the chamber for accommodating the rings taken out by the take-out means. A sputtering apparatus. 3. A closed chamber to which substrates are intermittently supplied, an electrode provided in the chamber, a ring placed on the electrode, and a ring taken out of the electrode in the chamber. Moving means for returning on the electrode;
A sputtering apparatus, comprising: supply means for filling a ring with a granular target in a chamber; and a storage provided on a moving path of the ring by the moving means for storing the target in the ring.