JP2004084043A - Mask for thin film deposition and thin film deposition system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask for thin film deposition which never cause deformation even if sandblast treatment is repeated, and to provide a thin film deposition system provided with the same. <P>SOLUTION: The tip part of the mask for thin film deposition is formed of a hard material, so that deformation hardly occurs even if sandblast treatment is performed, and the service life of the mask can be elongated. Further, the body part of the mask for thin film deposition is formed of a material having satisfactory thermal conductivity such as Cu (copper), so that its heat radiability from a substrate of polycarbonate or the like is secured, and the problem as for the deformation of the substrate caused by heating can be solved as well. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thin-film deposition mask and a thin-film deposition apparatus, and more particularly to a thin-film deposition mask suitable for use in manufacturing an optical disc, an optical component, and the like, and a thin-film deposition apparatus having the same.
[0002]
[Prior art]
2. Description of the Related Art In recent years, thin film deposition techniques in a vacuum or reduced-pressure atmosphere have been rapidly developed, and are being adopted in a wide range of industrial fields in manufacturing processes of various products. When depositing these thin films, there are cases where the thin films should be deposited with a part of the substrate on which the thin film is to be deposited covered by a "mask".
[0003]
For example, when manufacturing a CD (Compact Disk) or a DVD (Digital Versatile Disk), a central portion and a peripheral portion of a disc-shaped polycarbonate (PC) substrate are respectively covered with a mask, and only in a predetermined region. The optical thin film is deposited by sputtering.
[0004]
As a document which discloses a thin film deposition apparatus for continuously depositing such an optical thin film, for example, JP-A-2000-64042 can be cited.
[0005]
FIG. 9 is a conceptual diagram showing the entire configuration of the thin film deposition apparatus. That is, the apparatus illustrated in the figure is a sputtering apparatus for depositing a thin film on a disk-shaped substrate such as a CD, and has a configuration in which a substantially cylindrical substrate transfer chamber 312 and a substantially cylindrical sputter chamber 311 are connected. Have. The disk substrate 301, which is an object to be processed, is placed on a susceptor 302 of a disk, and the rotating mechanism 303 is rotated in a direction of an arrow C in a state where the disk substrate 301 is placed on a transfer table 310, thereby The substrate is transferred in the substrate transfer chamber 312.
[0006]
The loading and unloading of the disk substrate 301 is performed through the opening 306 of the transfer chamber. At this time, the disk substrate 301 is lifted in the direction of arrow B by the susceptor pusher 308 together with the susceptor 302. Then, the disk substrate 301 is shielded from the transfer chamber 312 by the seal mechanism 320 provided between the transfer chamber 312 and the susceptor 302 and the seal mechanism 322 provided between the susceptor 302 and the susceptor pusher 308. State. That is, the substrate 301 can be taken in and out of the atmosphere through the opening 306 while the transfer chamber 312 is kept in a vacuum state. At this time, vacuum breakage and vacuum roughing of the space below the opening 306 can be appropriately performed via a gate valve (not shown).
[0007]
On the other hand, during sputtering, the disk substrate 301 is transported below the sputtering chamber 311 by the rotating mechanism 303 and lifted in the direction of arrow D by the pusher 309. Then, the substrate 301 is pressed against the center mask 330 and the outer mask 340, and the vicinity of the center and the periphery of the substrate 301 are masked. By operating the sputtering source 307 in this state, a thin film can be deposited only on a predetermined region of the substrate 301. Note that these masks 330 and 340 are formed of Cu (copper) having good thermal conductivity in order to suppress heating of the substrate during sputtering.
[0008]
The apparatus shown in FIG. 9 can realize extremely high productivity when an optical thin film is deposited on a disk substrate such as a CD or DVD.
[0009]
[Problems to be solved by the invention]
By the way, in the case of the apparatus illustrated in FIG. 9, since a thin film is deposited on the surface of the center mask 330 and the outer mask 340 provided in the sputtering chamber 311, it is necessary to clean these at predetermined intervals.
[0010]
In manufacturing a conventional CD, Al (aluminum) is often deposited on a substrate. In this case, a method of removing the masks 330 and 340 from the apparatus and cleaning with a predetermined etching solution (such as a sodium hydroxide solution). Has been widely used.
[0011]
On the other hand, in the case of a DVD whose demand is rapidly increasing in recent years, it is necessary to deposit Si (silicon). However, since there is no suitable etchant for removing the silicon film, the cleaning of the masks 330 and 340 needs to be performed exclusively by “sand blast”. “Sand blasting” is a method of spraying fine particles of, for example, aluminum oxide having a particle diameter of about 1 mm onto the surface of a processing object at a pressure of about several kgf / cm ² .
[0012]
However, as a result of the study of the present inventor, it has been found that deformation of the mask of the thin film deposition apparatus, particularly the outer mask 340, is often caused by sandblasting.
[0013]
FIG. 10A is a schematic view showing a cross-sectional structure of an outer mask and a blast jig thereof which are prototyped by the inventor in the process leading to the present invention. That is, the outer mask 340 and the mask retainer 360 for fixing the outer mask 340 are removed from the thin film deposition apparatus and attached to the blast jig 400. Here, the outer mask 340 and the mask retainer 360 are each formed of Cu (copper) having good thermal conductivity.
[0014]
When cleaning them, sandblasting is performed in a state where the screws 420 are inserted into the screw holes 360M provided in the mask retainer 360 and fixed to the blast jigs 400A and 400B.
[0015]
However, when the sandblasting process is repeated in this state, the portion near the tip of the mask 340 tends to “warp” in the direction indicated by the arrow A, and the tip thereof tends to “stretch” in the direction indicated by the arrow B. It turned out that there is.
[0016]
FIG. 10B is a schematic diagram for explaining deformation of the mask tip. As illustrated in the figure, the portion near the tip of the outer mask 340 is entirely lifted in the direction of arrow A by sandblasting, and the tip is further extended in the direction of arrow B, so that "the neck is lifted." As if ".
[0017]
When the mask 340 is deformed in this manner, the area to be masked on the substrate 301 expands, so that the position and size of the thin film formation area deviate from the DVD standard. In order to prevent this, the mask 340 needs to be renewed frequently, and there is a problem that the life of the mask 340 is short.
[0018]
By the way, in order to extend the life of the mask 340, an attempt was made to lower the pressure of sandblasting or to reduce the particle size of blasting.
[0019]
However, when the pressure is reduced, the processing time required for blasting tends to be accelerated, and it has been difficult to effectively suppress the deformation of the mask.
[0020]
When the particle size of the blast was reduced, the silicon film tended to peel off from the mask surface before reaching a predetermined mask life. This is considered to be a phenomenon corresponding to the surface state of the mask due to the blast processing. Therefore, the life of the mask is rather shortened.
[0021]
On the other hand, in order to suppress the deformation of the mask 340, it is conceivable to increase the thickness of the tip. However, when the thickness of the tip of the mask 340 is increased, the so-called “shadowing effect” tends to decrease the film thickness of the thin film formation region adjacent thereto, and the film thickness distribution satisfying the DVD standard is satisfied. The problem of disappearing occurs.
[0022]
As described above, when an optical thin film such as a DVD is deposited using a conventional thin film deposition mask, the mask is deformed by sandblasting, and there is no effective means to eliminate the deformation.
[0023]
The present invention has been made based on the recognition of such a problem, and an object of the present invention is to provide a thin film deposition mask that does not deform even when sandblasting is repeated, and a thin film deposition apparatus including the same.
[0024]
[Means for Solving the Problems]
To achieve the above object, a thin film deposition mask of the present invention is a thin film deposition mask for masking a predetermined region of the substrate when depositing a thin film on the substrate,
In the thin film deposition mask, a mask tip for masking the predetermined region is made of a first material having a hardness equal to or higher than stainless steel.
[0025]
According to the above configuration, it is possible to prevent deformation of the tip of the mask even if the sandblasting process is repeated, thereby extending the life of the mask and improving the production efficiency.
[0026]
Here, if stainless steel, Ti (titanium), W (tungsten), Ta (tantalum), Mo (molybdenum), or an alloy of these as a main component is used as the first material, deformation due to sandblasting can be caused. This is advantageous in that it hardly occurs and degassing is small even in a vacuum.
[0027]
In addition, if a mask body made of a second material having higher thermal conductivity than the first material is further provided, heat radiation from the substrate can be ensured, and heat generated by sputtering or the like can be obtained. Deformation of the substrate can be effectively prevented.
[0028]
Further, it is advantageous to use a material containing Cu (copper) as a main component as the second material in that heat conductivity is high.
[0029]
Further, if a screw hole is provided at the mask tip, it becomes possible to fix the mask tip to the blast jig at the time of sandblasting using the screw hole, and the deformation of the mask tip is more effectively achieved. Can be deterred.
[0030]
Further, when the thin film deposition mask is used as an outer mask for DVD production, the silicon thin film can be stably formed based on the DVD standard that requires a high level of film thickness uniformity without frequently changing the mask. It can be deposited, which is very advantageous.
[0031]
On the other hand, the thin film deposition apparatus of the present invention is configured to include any one of the above masks for thin film deposition, has a long mask life, and is suitable for manufacturing DVDs and the like.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0033]
FIG. 1 is a conceptual diagram schematically illustrating a cross-sectional configuration of a main part of a thin film deposition mask according to an embodiment of the present invention.
[0034]
That is, the thin-film deposition mask 140 of the present embodiment has a substantially donut shape in order to mask the peripheral portion of the disk-shaped disk substrate 301. And it has a mask tip part 140A provided on the inner peripheral side and a main body part 140B provided on the outer peripheral side.
[0035]
The tip 140A is formed of a relatively hard material such as stainless steel, for example, and the main body 140B is formed of a material having good heat conductivity such as Cu (copper).
[0036]
Such a mask 140 is incorporated in, for example, a sputtering chamber of a thin film deposition apparatus as illustrated in FIG. 9, and its tip 140A has a role of masking a part of the substrate.
[0037]
According to the present invention, since the tip portion 140A of the mask is formed of a hard material, deformation is small even when sand blasting is performed, and the life of the mask can be extended. As a material for forming the tip portion 140A, a material that is hard, has little degassing in vacuum, and is easy to process is desirable. Specifically, stainless steel or a material having a hardness or tensile strength equal to or higher than that of stainless steel is desirable. These alloys can be used.
[0038]
On the other hand, by forming the main body portion 140B from a material such as Cu (copper) having good thermal conductivity, heat radiation from a substrate such as polycarbonate is secured, and problems such as deformation of the substrate due to heating are eliminated. Can be.
[0039]
Joining of the mask tip 140A and the mask body 140B can be performed by welding or the like. For example, when the distal end portion 140A is formed of stainless steel and the main body portion 140B is formed of Cu (copper), the joining can be reliably performed by electron beam welding or brazing.
[0040]
On the other hand, according to the present invention, by providing a screw hole 140M for fixing to the blast jig at the tip of the mask, deformation such as “warping” of the tip of the mask can be more effectively suppressed.
[0041]
FIG. 2 is a cross-sectional view schematically illustrating a state in which the outer mask of the present invention is fixed to a blast jig. That is, in the case of the outer mask 140 of the present invention, the fixing screw holes 140M are provided at the mask tip 140A. Then, it is fixed to the blast jigs 400A and 400B by the screws 420. When sandblasting is performed in this state, the tip portion of the mask 140 is securely fixed to the blast jig 400, and "warping" of the mask tip portion 140A can be suppressed extremely effectively.
[0042]
Furthermore, according to the present invention, by providing the screw hole 140M in the mask tip 140A made of a hard material such as stainless steel, deformation of the screw hole can be suppressed, and from this point, the life of the mask can be extended. That is, in the case of the conventional outer mask 340 illustrated in FIG. 10, a screw hole 360M for fixing is formed in a mask retainer 360 made of a soft material such as Cu (copper), and a screw 420 such as stainless steel is screwed into the blast. The jig 400 was fixed. However, in this case, in order to form the screw hole 360M, it is necessary to use a component such as "Helisert", and the life of the screw hole 360 cannot be extended much.
[0043]
On the other hand, according to the present embodiment, the screw hole 140M can be tapped on the mask tip 140A made of a hard material such as stainless steel, so that the screw hole 140M can be easily formed and the life can be greatly extended. .
[0044]
FIG. 3 is a schematic diagram illustrating a cross-sectional structure of an outer mask according to a second embodiment of the present invention. That is, the mask 140 of the present embodiment is formed not only of the tip portion but also of a hard material such as stainless steel as a whole. A screw hole 140M for fixing to a blast jig is provided near the tip.
[0045]
In the present embodiment, the material of the mask tip 140A in the first embodiment can be used as the material forming the mask 140. In this case, the thermal conductivity is lower than that of a mask using Cu (copper) or the like. However, depending on conditions such as sputtering conditions and the material of the substrate, heating of the substrate can be suppressed to an allowable range. For example, when the electric power supplied during sputtering is relatively small, the temperature rise of the substrate is small, so that an outer mask made of stainless steel or the like may be used in some cases.
[0046]
The present embodiment is advantageous in that the deformation of the mask can be reliably suppressed in such a case.
[0047]
The inventor prototyped the outer masks of the first and second embodiments described above and measured the amount of deformation by sandblasting together with the prototype masks for comparison.
[0048]
FIG. 4 and FIG. 5 are schematic diagrams showing a cross-sectional structure of the prototype mask. That is, FIG. 4A shows a state in which a conventional mask formed entirely of Cu (copper) is fixed to a blast jig 400 as in the case of FIG.
[0049]
FIG. 4B shows a state in which a conventional mask similar to that shown in FIG. 4A is fixed to an improved blast jig. That is, the blast jig of FIG. 9 is provided with an eave-shaped cover 410 on the mask tip, and is designed so that the mask tip is not directly exposed to the blast. However, this blast jig is for examining the effect of sandblasting at the tip of the mask, and has a disadvantageous structure in removing deposits at the tip of the mask.
[0050]
FIG. 5A shows a state in which the mask according to the second embodiment of the present invention is fixed to a blast jig. Here, the prototype mask was formed entirely of stainless steel (SUS304).
[0051]
FIG. 5B shows a state in which the mask according to the first embodiment of the present invention is fixed to a blast jig. In the mask manufactured here, the tip 140A was formed of stainless steel (SUS304), and the main body was formed of Cu (copper). Further, as these joining methods, two kinds of methods, ie, electron beam welding and brazing, were employed.
[0052]
Sand blasting was repeated 20 times for each of the masks described above, and the dimensions of each part were measured. The blast used was aluminum oxide particles having a particle size of ♯20 (about 1 mmφ), the ejection pressure was 4 kgf / cm ² , and the time of one blast treatment was 2 minutes.
[0053]
As shown in FIGS. 4 and 5, the dimensions measured for each mask are “height A” representing “warping” in the portion of arrow A, “height B” in the portion of arrow B, and the height of the mask. This is the “radius R” of the inner peripheral tip.
[0054]
FIG. 6 is a graph showing the change in height A due to the sandblasting process for each mask. That is, the horizontal axis in the figure represents the number of times of sandblasting, and the vertical axis in the figure represents the height A.
[0055]
Here, "Cu mask" is shown in FIG. 4A, "Improved jig" is shown in FIG. 4B, "SUS mask" is shown in FIG. 5A, and "Cu + SUS" is shown in FIG. 5B. Respectively. Further, “Cu + SUS-EB” indicates a result of electron beam welding between the mask tip and the main body, and “Cu + SUS-BR” indicates a result obtained by brazing the mask tip and the main body.
[0056]
In FIG. 6, first, when looking at a “Cu mask”, that is, a conventional mask formed entirely of Cu (copper), as the sandblasting process is repeated, the tip is lifted up in the direction of arrow A, and the deformation is increased. I understand.
[0057]
Also, when the "improved jig", that is, a jig in which the tip of the mask is covered with the eaves-shaped cover 410 is used, the tip of the mask is lifted in the direction of arrow A, and the deformation is progressing.
[0058]
On the other hand, in the case of the “SUS mask” according to the second embodiment of the present invention, it can be seen that the deformation amount A is reduced to about half as compared with the conventional “Cu mask”. However, the deformation amount A is larger than that of the mask according to the first embodiment described below. This is probably because the tip was not fixed to the blast jig 400 using the screw 420.
[0059]
On the other hand, in the case of the “Cu + SUS” mask according to the first embodiment of the present invention, the deformation amount A is extremely small in both the case where the electron beam welding is performed and the case where the mask is brazed, and the “warping” of the mask is almost eliminated. You can see that.
[0060]
FIG. 7 is a graph showing the change in height B associated with the sandblasting process for each mask. That is, the horizontal axis in the figure represents the number of times of sandblasting, and the vertical axis in the figure represents the height B. Also, the legend relating to FIG. 6 is the same as that described above with reference to FIG.
[0061]
From FIG. 7, the height B, that is, the lift amount of the mask tip is extremely large in the case of the conventional Cu mask, and the height B does not decrease so much even if the improved jig is used for this.
[0062]
In comparison with these, in the case of the “SUS mask” of the second embodiment of the present invention, the height B is suppressed to be small.
[0063]
Further, in the case of the “Cu + SUS” mask according to the first embodiment of the present invention, it can be seen that the deformation of the thin portion at the tip of the mask is almost eliminated.
[0064]
FIG. 8 is a graph showing the radius R of the inner peripheral end of each mask accompanying the sandblasting process. Here, the legend related to the figure is the same as that described above with reference to FIG.
[0065]
FIG. 8 shows that in the case of the conventional Cu mask, the radius R becomes smaller as the sandblasting process is repeated. This is because the thin portion at the tip of the mask extends toward the tip. As described above, when the radius R of the mask is reduced, the masking region is enlarged, and there arises a problem that requirements such as the DVD standard cannot be satisfied.
[0066]
On the other hand, when the improved jig provided with the eaves-shaped cover 410 is used, since the mask tip is protected from the blast, “elongation” is also suppressed. However, when this jig is used, the tip of the mask cannot be cleaned by blast.
[0067]
In comparison, in the case of the “SUS mask” according to the second embodiment of the present invention, the decrease in the radius R is suppressed to a very small amount. That is, the change of the masking region is suppressed, and the life of the mask can be extended.
[0068]
Similarly, in the case of the “Cu + SUS” mask according to the first embodiment of the present invention, the decrease in the radius R can be suppressed to a very small amount, and the mask life can be extended.
[0069]
As described above, according to the present invention, by forming at least the tip portion of the mask with a hard material such as stainless steel, it is possible to effectively suppress deformation accompanying sandblasting. As a result, it is possible to eliminate a decrease in the production yield such as DVD production due to the fluctuation of the masking region, and to prolong the mask life.
[0070]
Next, the inventor measured an increase in temperature when the mask of the first embodiment was used. Specifically, using the “Cu + SUS” mask illustrated in FIG. 5B, 500 DVD disks were continuously formed by sputtering, and the temperature at the tip of the mask was measured. The sputtering conditions are as follows: input power: 2.4 kW, sputtering time: 2.8 seconds, argon flow rate: 25.0 SCCM, and tact time: 3.8 seconds.
[0071]
As a result, the temperature of the mask tip 140A is less than 48 ° C. in both the case where the tip 140A and the main body 140B are welded by electron beam and the case where the tip 140A is welded to the main body 140B. It was confirmed that it was suppressed.
[0072]
The embodiment of the invention has been described with reference to the examples. However, the present invention is not limited to these specific examples.
[0073]
For example, the shape of the mask is not limited to the one shown in the drawings, and the shape of the mask is appropriately changed according to the structure of the thin film deposition apparatus, the shape of the object to be deposited, the pattern of the area to be deposited, and the like. Is done.
[0074]
Further, the balance between the mask tip and the main body is not limited to the illustrated one, and one appropriately determined in consideration of the deformation amount and the thermal conductivity is included in the scope of the present invention.
[0075]
Further, the method of depositing a thin film is not limited to sputtering, but may be any of various other deposition methods such as electron beam evaporation, a reactive evaporation method performed in an oxidizing atmosphere, or the like, and a chemical vapor deposition method (Chemical Vapor Deposition). ) And those using various methods such as an ion plating method are included in the scope of the present invention.゜ [Effect of the invention]
The present invention is implemented in the form described above, and has the effects described below.
[0076]
First, according to the present invention, the tip of the thin film deposition mask is formed of a hard material, so that even if sand blasting is performed, there is little deformation and the life of the mask can be extended.
[0077]
Further, according to the present invention, the main body of the mask for thin film deposition is formed of a material such as Cu (copper) having good thermal conductivity, thereby ensuring heat radiation from a substrate such as polycarbonate, and Problems such as deformation of the substrate can also be solved.
[0078]
Furthermore, by providing a screw hole for fixing to the blast jig at the tip of the mask, deformation such as “warping” of the tip of the mask can be more effectively suppressed.
[0079]
Still further, according to the present invention, by forming the entire thin film deposition mask from a hard material such as stainless steel, there is no need for labor such as welding or brazing, and a thin film deposition mask having a long life and less deformation is provided. can do.
[0080]
As described above, according to the present invention, the life of a thin film deposition mask can be extended, thin film manufacturing processes for various products such as DVDs can be performed quickly and at low cost, and industrial advantages are great. is there.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically illustrating a main configuration of a thin film deposition mask according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view schematically illustrating a state in which the outer mask of the present invention is fixed to a blast jig.
FIG. 3 is a schematic diagram illustrating a cross-sectional structure of an outer mask according to a second embodiment of the present invention.
FIG. 4 is a schematic view illustrating a cross-sectional structure of a mask prototyped by the present inventors.
FIG. 5 is a schematic diagram illustrating a cross-sectional structure of a mask prototyped by the present inventors.
FIG. 6 is a graph showing a height A associated with sandblasting for each mask.
FIG. 7 is a graph showing height B associated with sandblasting for each mask.
FIG. 8 is a graph showing a radius R associated with sandblasting for each mask.
FIG. 9 is a conceptual diagram illustrating an entire configuration of a thin film deposition apparatus.
10A is a schematic diagram showing a cross-sectional structure of an outer mask and a blast jig thereof experimentally manufactured by the inventor in the process leading to the present invention, and FIG. 10B is a diagram illustrating deformation of a mask tip portion. FIG.
[Explanation of symbols]
140 Outer mask 140A Mask tip 140B Mask body 140M Screw hole 301 Disk substrate 301 Substrate 302 Susceptor 303 Rotation mechanism 306 Transport chamber opening 306 Opening 307 Sputter source 308 Susceptor pusher 309 Pusher 310 Transport table 311 Sputter chamber 311 Sputter chamber 312 Substrate transfer chamber 312 Transfer chamber 320 Seal mechanism 322 Seal mechanism 330 Center mask 340 Outer mask 360 Mask hold 360M Screw hole 400 Blast jig 400A, 400B Blast jig 410 Cover

Claims (7)

A thin film deposition mask for masking a predetermined region of the substrate when depositing a thin film on the substrate,
The thin-film deposition mask according to claim 1, wherein, of the thin-film deposition mask, a mask tip for masking the predetermined region is made of a first material having a hardness equal to or higher than stainless steel. 2. The thin film deposition apparatus according to claim 1, wherein the first material is mainly composed of stainless steel, Ti (titanium), W (tungsten), Ta (tantalum), Mo (molybdenum), or an alloy thereof. mask. 3. The thin film deposition mask according to claim 1, further comprising a mask main body made of a second material having a higher thermal conductivity than the first material. 4. The thin film deposition mask according to claim 3, wherein the second material is mainly composed of Cu (copper). The thin film deposition mask according to any one of claims 1 to 4, wherein a screw hole is provided at the tip of the mask. The thin film deposition mask according to any one of claims 1 to 5, wherein the thin film deposition mask is an outer mask for manufacturing a DVD. A thin film deposition apparatus comprising the thin film deposition mask according to claim 1.

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