JP2009054512A - Mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask which can hardly reduce aligning accuracy between the mask and a deposited substrate. <P>SOLUTION: An opening 3 corresponding to a thin-film pattern formed on a depositied substrate and a mask alignment section 4 used for aligning with the deposited substrate are formed on a plate-shaped mask substrate 2. The mask alignment section 4 is a recessed section with an end face of the opening facing a deposited surface of the deposited substrate, wherein roughness of a bottom face is different from roughness of an upper surface of the mask substrate 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mask used for vapor deposition, for example.

In recent years, development of light-emitting panels using organic EL (Electroluminescence) has been actively conducted. In such a light emitting panel, that is, an organic EL device, for example, a vapor deposition mask is used when vaporizing low molecular materials separately for each RGB.
An alignment mark for performing mutual alignment is formed on each of the vapor deposition mask and the deposition target substrate. The alignment of the mask and the film formation substrate is performed, for example, by irradiating illumination light toward the mask and the film formation substrate from above in the overlapping direction in a state where the mask and the film formation substrate are overlapped. This is performed by relatively moving the mask and the film formation substrate while detecting each alignment mark by the imaging means (see, for example, Patent Document 1). The alignment mark is constituted by, for example, a through hole formed in the mask.
JP-A-11-158605

  However, the following problems remain in the conventional mask. That is, in the above conventional mask, the vapor deposition is deposited on the deposition target substrate through the through hole of the alignment mark during vapor deposition. For this reason, when depositing a deposition object using a deposition mask on the deposition target substrate on which the deposition object is deposited, it may be difficult to detect the alignment mark due to the deposition material deposited via the alignment mark. Accordingly, there is a problem that the alignment accuracy between the mask and the deposition target substrate is lowered.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a mask in which the alignment accuracy between the mask and the deposition target substrate is not easily lowered.

  The present invention employs the following configuration in order to solve the above problems. That is, in the mask according to the present invention, an opening corresponding to a thin film pattern formed on the film formation substrate and an alignment unit used for alignment with the film formation substrate are formed on the plate-shaped mask substrate. The alignment unit has an opening end surface facing the film formation surface of the film formation substrate, and a roughness of the bottom surface is a surface roughness of at least a peripheral region of the alignment unit on a surface of the mask substrate facing the film formation substrate. It is characterized by being a different recessed part.

In this invention, since the alignment portion is formed as a recess to prevent the thin film forming material from being deposited on the film formation substrate via the mask, the alignment accuracy between the mask and the film formation substrate is unlikely to decrease.
That is, at the time of film formation using the mask, the thin film forming material directed to the mask is deposited on the film formation surface through the opening to form a thin film pattern. However, since the thin film forming material is deposited on a region corresponding to the formation region of the alignment portion on the mask substrate, it is not deposited on the deposition target substrate via the alignment portion. Therefore, the alignment accuracy between the deposition target substrate using the alignment unit and the mask does not decrease.
Further, by making the roughness of the bottom surface different from the surface roughness of the mask substrate, the contrast of the alignment portion with respect to the mask substrate can be obtained at the time of alignment, and the position of the alignment portion on the mask substrate can be detected. When the bottom surface of the alignment unit is rougher than the surface of the mask substrate, the alignment unit is detected darker than the mask substrate. On the other hand, when the bottom surface of the alignment unit is flatter than the surface of the mask substrate, the alignment unit is detected brighter than the mask substrate.

Further, in the mask according to the present invention, the surface roughness of the surface facing the film formation substrate at least in the peripheral region of the alignment portion of the mask substrate is such that the roughness of the bottom surface of the recess and the film formation substrate are the same. It is preferable to be between the surface roughness in the other alignment portion that is formed and used for alignment.
In this invention, it becomes easier to detect the two alignment portions by setting the surface roughness of the mask substrate to a value between the roughness of the bottom surface of the alignment portion and the surface roughness of the other alignment portions. That is, as described above, for example, when the bottom surface of the alignment unit is rougher than the surface of the mask substrate, the alignment unit is detected darker than the mask substrate. At this time, since the surface of the other alignment unit is flatter than the surface of the mask substrate, the other alignment unit is detected brighter than the mask substrate. In this way, one of the two alignment portions is detected brighter than the mask substrate, and the other is detected darker than the mask substrate, thereby improving the contrast of the two alignment portions. Therefore, the alignment accuracy between the mask and the deposition target substrate is further improved.

In the mask according to the present invention, the mask substrate includes a lower substrate and an upper substrate bonded to each other, and the opening is formed in the first opening formed in the lower substrate and the upper substrate. It is preferable that the second opening and the second opening communicate with the first opening.
In the present invention, the alignment portion can be formed more easily by bonding the lower substrate and the upper substrate.

In the mask according to the present invention, it is preferable that the alignment portion is formed by the lower substrate covering an opening end surface of a through hole formed in the upper substrate.
In the present invention, the degree of freedom in designing the upper substrate is improved, for example, the upper substrate can be made sufficiently thinner than the lower substrate.

In the mask according to the present invention, the surface roughness of the lower substrate is preferably different from the surface roughness of the upper substrate.
In this invention, since the bottom surface of the alignment part becomes the surface of the lower substrate, the roughness of the bottom surface of the alignment part is made different from the roughness of the surface of the upper substrate by making the surface roughnesses of the upper substrate and the lower substrate different. be able to. Therefore, the alignment part can be easily formed.

In the mask according to the present invention, the upper substrate and the substrate described above are preferably formed of different materials.
In the present invention, it is not necessary to separately perform a process for making the surface roughness of the upper substrate and that of the lower substrate different, so that the alignment portion can be formed more easily.

In the mask according to the present invention, the lower substrate is preferably made of a magnetic material.
According to the present invention, the mask and the deposition target substrate can be easily held by aligning the mask and the deposition target substrate and then attracting the mask with the magnetic force through the deposition target substrate. Thereby, positional deviation between the mask and the deposition target substrate can be suppressed.

In the mask according to the present invention, the lower substrate is preferably thicker than the upper substrate.
In this invention, the rigidity of the mask substrate can be increased and the mechanical strength of the mask can be increased.

In the mask according to the present invention, it is preferable that the first opening is larger than the second opening.
In the present invention, even if the thin film forming material flies from an oblique direction with respect to the mask, it is prevented from being obstructed by the wall of the opening. Thereby, the perpendicularity of the deposited thin film pattern can be improved.

[First Embodiment]
Hereinafter, a first embodiment of a mask according to the present invention will be described with reference to the drawings. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size. Here, FIG. 1 is a plan view showing a mask, and FIG. 2 is a schematic sectional view of FIG.

The mask 1 is a mask used, for example, when forming a pixel pattern constituting an organic EL device. As shown in FIGS. 1 and 2, the mask 1 is formed using a plate-shaped mask substrate 2 having a substantially rectangular shape in plan view. Has been.
The mask substrate 2 is made of, for example, a metal material, and an opening 3 and a mask alignment part (alignment part) 4 are formed. The thickness of the mask substrate 2 is, for example, 40 μm or more and 1 mm or less.

The opening 3 is a through-hole formed in the mask substrate 2 and has a shape corresponding to a thin film pattern on the deposition target substrate 10 to be described later. The opening 3 is formed by performing an etching process on the mask substrate 2.
The mask alignment unit 4 is a recess formed in the mask substrate 2 and is used for alignment between the mask 1 and the deposition target substrate 10. The opening end surface of the mask alignment unit 4 is formed on the upper surface facing the deposition target substrate 10 when vapor deposition using the mask 1 is performed. The mask alignment unit 4 is formed at each of two opposing corners of the mask substrate 2 and has a circular shape in plan view. The mask alignment unit 4 is formed by performing an etching process on the mask substrate 2.

The surface roughness of the upper surface of the mask substrate 2 is smaller than the roughness of the bottom surface of the mask alignment unit 4. That is, the upper surface of the mask substrate 2 is flatter than the bottom surface of the mask alignment unit 4.
A magnetic film (not shown) is formed on the upper surface of the mask substrate 2 by a sputtering method or the like.

Next, a method of manufacturing the mask 1 having the above configuration will be described with reference to FIG.
First, resist layers 5 and 6 are formed on the upper and lower surfaces of the mask substrate 2 by using a photolithography technique or the like (FIG. 3A). Here, the resist layer 5 covers the upper surface of the mask substrate 2, and an opening 5 a is formed in a region where the opening 3 and the mask alignment part 4 are formed. The resist layer 6 covers the lower surface of the mask substrate 2, and an opening 6 a is formed in the region where the opening 3 is formed.

  Then, wet etching is performed on the mask substrate 2 using the resist layers 5 and 6 as a mask (FIG. 3B). Here, an acid-based etchant is used. At this time, since the openings 5a and 6a of the resist layers 5 and 6 are formed on the upper and lower surfaces of the mask substrate 2 in the region where the opening 3 is formed, the etching proceeds from both the upper and lower surfaces of the mask substrate 2. As a result, the opening 3 is formed in the mask substrate 2. In the region where the mask alignment portion 4 is formed, the opening 5 a of the resist layer 5 is formed only on the upper surface of the mask substrate 2, and the lower surface of the mask substrate 2 is covered with the resist layer 6. Therefore, etching proceeds from the upper surface of the mask substrate 2. Thereby, the mask substrate 2 is half-etched and the mask alignment part 4 is formed. Further, the bottom surface of the mask alignment unit 4 becomes rougher than the upper surface of the mask substrate 2 by the wet etching process.

Next, a film formation substrate on which a thin film pattern is formed using the mask 1 having the above configuration will be described with reference to FIG. Here, FIG. 4 is a plan view showing a film formation substrate.
The deposition target substrate 10 is substantially rectangular in plan view, and is mainly formed of a light-transmitting material such as glass. For example, the deposition target substrate 10 is a transparent substrate for an organic EL device. Then, substrate alignment portions (other alignment portions) 11A and 11B for aligning with the mask 1 are formed at two corner portions facing each other on the surface of the deposition target substrate 10, respectively.

The substrate alignment portions 11 </ b> A and 11 </ b> B are convex portions formed on the film formation substrate 10, and are formed by patterning the surface of the film formation substrate 10. The substrate alignment portions 11A and 11B are respectively formed at two opposing corner portions of the deposition target substrate 10. The substrate alignment portion 11A has a cross shape in plan view, and the substrate alignment portion 11B has a circular shape in plan view.
The surface roughness of each of the substrate alignment portions 11 </ b> A and 11 </ b> B is smaller than the surface roughness on the upper surface of the mask substrate 2. That is, the surface of each of the substrate alignment portions 11 </ b> A and 11 </ b> B is flatter than the upper surface of the mask substrate 2. Therefore, among the surfaces of the substrate alignment portions 11A and 11B, the upper surface of the mask substrate 2, and the bottom surface of the mask alignment portion 4, the surfaces of the substrate alignment portions 11A and 11B are the flattest and the bottom surface of the mask alignment portion 4 is the roughest. It has become.

Next, a film forming apparatus 20 that forms a thin film pattern on the film formation substrate 10 using the mask 1 will be described with reference to FIG.
As shown in FIG. 5, the film forming apparatus 20 controls a chamber 21, a frame 22, a vapor deposition source 23, a permanent magnet 24, an imaging unit 25, an illumination unit 26, a moving mechanism 27, and these. And control means 28.
The frame 22 is configured to hold the outer peripheral edge of the mask 1. The vapor deposition source 23 is formed of a film forming material to be deposited on the film formation substrate 10. The permanent magnet 24 is configured to hold the mask 1 and the deposition target substrate 10 by an attractive force generated between the permanent magnet 24 and the magnetic film formed on the upper surface of the mask substrate 2.

The imaging means 25 is configured to image each of the mask alignment unit 4 and the substrate alignment units 11A and 11B. The imaging means 25 is composed of, for example, a CCD (Charge Coupled Device), and is formed at two corners of the mask alignment unit 4 and the deposition target substrate 10 formed at two corners of the mask 1. It is provided in two places so that each of board | substrate alignment part 11A, 11B may be imaged.
The illumination means 26 constitutes an epi-illumination system that irradiates illumination light onto the mask 1 and the deposition target substrate 10 from above in the overlapping direction. Note that since the deposition target substrate 10 is formed of a light-transmitting material, the illumination light irradiated toward the deposition target substrate 10 passes through the deposition target substrate 10 and is also irradiated to the mask 1. The
The moving mechanism 27 is configured to move the mask 1 relative to the deposition target substrate 10.
The control unit 28 is configured to detect the mask alignment unit 4 and the substrate alignment units 11 </ b> A and 11 </ b> B from the imaging result of the imaging unit 25 and align the mask 1 and the deposition target substrate 10 with the moving mechanism 27. .

  In the film forming apparatus 20 having such a configuration, the imaging unit 25 detects the mask alignment unit 4 and the substrate alignment units 11A and 11B in a state where the mask 1 and the deposition target substrate 10 are overlapped with a gap. . At this time, as described above, among the surfaces of the substrate alignment portions 11A and 11B, the upper surface of the mask substrate 2 and the bottom surface of the mask alignment portion 4, the surfaces of the substrate alignment portions 11A and 11B are the flattest, The bottom surface of 4 is the roughest. Therefore, in the image acquired by the imaging unit 25, the mask alignment unit 4 is displayed darker than the mask substrate 2 and the substrate alignment units 11A and 11B are displayed brighter than the mask substrate 2 as shown in FIG. .

  The control unit 28 detects the mask alignment unit 4 and the substrate alignment units 11A and 11B from the image acquired by the imaging unit 25 so that the mask alignment unit 4 and the substrate alignment units 11A and 11B are in a predetermined positional relationship. The moving mechanism 27 is controlled. At this time, since the mask alignment unit 4 is displayed darker than the mask substrate 2 and the substrate alignment units 11A and 11B are displayed brighter than the mask substrate 2, the space between the mask alignment unit 4 and the substrate alignment units 11A and 11B is displayed. Improves the contrast. Therefore, the control unit 28 can accurately detect the mask alignment unit 4 and the substrate alignment units 11A and 11B.

  The moving mechanism 27 moves the mask 1 with respect to the deposition target substrate 10. As described above, the mask 1 and the deposition target substrate 10 are aligned. Thereafter, the permanent magnet 24 holds the mask 1 and the deposition target substrate 10 by adsorbing the magnetic film formed on the mask 1. In this state, the film forming apparatus 20 deposits a thin film forming material on the deposition target substrate 10 from the vapor deposition source 23 through the opening 3 to form a thin film pattern. At this time, since the mask alignment portion 4 is formed by the concave portion, the thin film forming material generated from the vapor deposition source 23 is not deposited in a region other than the opening 3.

As described above, according to the mask 1 in the present embodiment, the mask alignment unit 4 is used as a recess to prevent the deposit from being deposited on the edge of the deposition target substrate 10 during deposition. Vapor deposition using the mask 1 can be performed a plurality of times without lowering the alignment accuracy with the substrate 10.
Further, the mask alignment unit 4 and the substrate alignment in the image acquired by the imaging means 25 are made by roughening the bottom surface of the mask alignment unit 4 with respect to the upper surface of the mask substrate 2 and flattening the surfaces of the substrate alignment units 11A and 11B. The contrast with the portions 11A and 11B is improved. Therefore, the detection accuracy of the mask alignment unit 4 and the substrate alignment units 11A and 11B by the control unit 28 is improved, so that the mask 1 and the deposition target substrate 10 are accurately aligned.

[Second Embodiment]
Hereinafter, a second embodiment of the mask according to the present invention will be described with reference to the drawings. In the present embodiment, the description will focus on the differences from the first embodiment, and the same reference numerals are given to the components described in the above embodiment, and the description thereof is omitted. Here, FIG. 7 is a schematic sectional view of the mask.

As shown in FIG. 7, the mask 50 in this embodiment includes a plate-like lower substrate 52 having a substantially rectangular shape in plan view and an upper substrate 53 joined to the lower substrate 52.
The lower substrate 52 is formed of a magnetic metal material such as SUS430, and the first opening 54 is formed. Further, the thickness of the lower substrate 52 is, for example, 1 mm.

  The first opening 54 is a through hole formed in the lower substrate 52, and the opening end surface thereof has a shape corresponding to the thin film pattern on the deposition target substrate 10. The first opening 54 is formed by performing an etching process on the lower substrate 52. Further, the entire upper surface of the lower substrate 52 facing the upper substrate 53 is etched, and the surface roughness of the upper substrate 53 is larger than that of the upper surface spaced from the lower substrate 52.

  The upper substrate 53 is made of, for example, a metal material such as SUS304, and a second opening 55 and an alignment hole (through hole) 56 are formed. Further, the thickness of the upper substrate 53 is 0.1 mm, for example, and is thinner than the lower substrate 52. The upper surface of the upper substrate 53 is rougher than the surfaces of the substrate alignment portions 11A and 11B.

The second opening 55 is a through-hole formed in the upper substrate 53 and has an opening end surface corresponding to the thin film pattern on the film formation substrate. The first and second openings 54 and 55 form an opening 57. Here, the first opening 54 is formed larger than the second opening 55.
The alignment holes 56 are through-holes formed in the upper substrate 53 and are respectively formed at two opposing corners of the upper substrate 53 and are circular in plan view. The alignment hole 56 is covered with the lower substrate 52 at the opening end face on the lower substrate 52 side. A mask alignment portion 58 is formed by the alignment hole 56 and the lower substrate 52 that closes the alignment hole 56. Therefore, the mask alignment portion 58 has an opening end surface formed on the upper surface of the upper substrate 53, and the lower substrate 52 is exposed on the bottom surface.
As described above, among the surfaces of the substrate alignment portions 11A and 11B, the upper surface of the upper substrate 53, and the bottom surface of the mask alignment portion 58, the surfaces of the substrate alignment portions 11A and 11B are the flattest, and the bottom surface of the mask alignment portion 58 is the most. It is rough.

Even with the mask 50 having the above-described configuration, the same operations and effects as described above can be achieved. However, the configuration in which the lower substrate 52 and the upper substrate 53 are joined increases the degree of freedom in designing the upper substrate 53.
Further, by making the surface roughness of the lower substrate 52 and the upper substrate 53 different, the mask alignment portion 58 can be easily formed.
By forming the lower substrate 52 from a magnetic material, it is not necessary to separately form a magnetic film on the mask 50 when the mask 50 and the deposition target substrate 10 are held and fixed using the permanent magnet 24. The manufacturing process can be simplified.
Furthermore, by making the lower substrate 52 thicker than the upper substrate 53, the mechanical strength of the mask 50 increases.
Further, by making the first opening 54 larger than the second opening 55, it is possible to prevent the lower substrate 52 from inhibiting the thin film forming material flying from the oblique direction toward the deposition target substrate 10 during the deposition. The perpendicularity of the thin film pattern formed on the deposition target substrate 10 is improved.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, the mask substrate only needs to have a surface roughness at least in the vicinity of the mask alignment portion that is different from the roughness of the bottom surface of the mask alignment portion.
Further, the bottom surface of the mask alignment portion is made rougher than the surface of the mask substrate and the surface of the substrate alignment portion is made flatter than the surface of the mask substrate, but the bottom surface of the mask alignment portion is made flatter than the surface of the mask substrate. At the same time, the surface of the substrate alignment portion may be made rougher than the surface of the mask substrate. Even if it does in this way, at the time of detection of each alignment part, since the mask alignment part is displayed brighter than the mask substrate and the substrate alignment part is displayed darker than the mask substrate, the contrast of each alignment part is improved. Detection accuracy is improved.
If the detection accuracy of each alignment unit can be maintained, both the bottom surface of the mask alignment unit and the surface of the substrate alignment unit may be rougher or flatter than the surface of the mask substrate.

In the second embodiment, the mask alignment portion is formed by covering the opening end surface of the alignment hole formed in the upper substrate with the lower substrate, but the roughness of the bottom surface of the mask alignment portion is that of the upper substrate. If it differs from the surface roughness, it may be formed by a recess formed in the upper substrate, or may be formed by a recess formed in the substrate as a through hole formed in the upper substrate.
The surface roughness of each substrate is made different by forming the upper substrate and the lower substrate with different materials. However, if the surface roughness of each substrate is made different by subjecting one of the substrates to surface roughening or plane processing. It may be allowed.
Furthermore, although the lower substrate is thicker than the upper substrate, the thickness of the lower substrate may be equal to or less than the thickness of the upper substrate.

The mask may have a configuration in which a plurality of plate-like mask chips each having an opening corresponding to the thin film pattern formed on a support substrate on the frame are fixed.
The mask is used for vapor deposition on the deposition target substrate, but may be used for depositing other thin film patterns such as sputtering or CVD (chemical vapor deposition).

It is a top view which shows the mask in the 1st Embodiment of this invention. It is a schematic sectional drawing of FIG. It is process drawing which shows the manufacturing process of a mask. It is a top view which shows a film-forming substrate. It is a block diagram which shows the thin film forming apparatus using a mask. It is explanatory drawing which shows the detection state of each alignment part. It is a schematic sectional drawing which shows the mask in 2nd Embodiment.

Explanation of symbols

1,50 mask, 2,51 mask substrate, 3,57 opening, 4,58 mask alignment unit (alignment unit), 10 deposition substrate, 11A, 11B substrate alignment unit (other alignment unit), 52 lower substrate 53 Upper substrate, 54 First opening, 55 Second opening, 56 Alignment hole (through hole)

Claims (9)

An opening corresponding to a thin film pattern formed on the film formation substrate and an alignment unit used for alignment with the film formation substrate are formed on the plate-shaped mask substrate,
The alignment unit has an opening end surface facing the film formation surface of the film formation substrate, and a roughness of the bottom surface is a surface roughness of at least a peripheral region of the alignment unit on a surface of the mask substrate facing the film formation substrate. A mask characterized by different concave portions.   In the mask substrate, the surface roughness of the surface facing the film formation substrate at least in the peripheral region of the alignment unit is different from the roughness of the bottom surface of the recess and the other surface formed on the film formation substrate and used for alignment. The mask according to claim 1, wherein the mask is between the surface roughness in the alignment portion. The mask substrate has a lower substrate and an upper substrate bonded to each other;
The opening is formed by a first opening formed in the lower substrate and a second opening formed in the upper substrate and communicating with the first opening. The mask according to 1 or 2.   The mask according to claim 3, wherein the alignment portion is formed by the lower substrate covering an opening end face of a through hole formed in the upper substrate.   The mask according to claim 4, wherein a surface roughness of the lower substrate is different from a surface roughness of the upper substrate.   The mask according to any one of claims 3 to 5, wherein the upper substrate and the above-described substrate are formed of different materials.   The mask according to claim 3, wherein the lower substrate is made of a magnetic material.   The mask according to claim 3, wherein the lower substrate is thicker than the upper substrate.   The mask according to any one of claims 3 to 8, wherein the first opening is larger than the second opening.

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