JP4817443B2 - Plasma mask CVD equipment - Google Patents

Description

  The present invention relates to a plasma type mask CVD apparatus.

  An organic EL (electroluminescence) element is manufactured by forming an electrode film or an RGB organic light emitting layer on a substrate. Therefore, usually, the exposed portions of the electrode and the organic layer are sealed with a protective film. As such a protective film, a film in which various inorganic films (silicon nitride films) are formed by a plasma CVD method is generally used. The plasma CVD method is a method in which a voltage is applied to the discharge space between the cathode electrode and the anode electrode facing each other, and the source gas is turned into a plasma to form a film on the substrate. There is an advantage of being.

As a plasma CVD apparatus, a deposition down (or face up) system in which a substrate is disposed on a lower electrode of the apparatus is generally known (see Patent Documents 1 and 2). On the other hand, the present inventors have proposed a deposition-up type CVD apparatus in which a substrate is disposed on the lower surface of the upper electrode of the apparatus (see Patent Document 3).
Further, since the protective film needs to be formed on a predetermined portion of the organic EL layer, the CVD film formation is usually performed using a mask.

JP 2005-339828 A (FIGS. 4 and 6) JP 2006-164543 A (FIG. 2) JP 2006-45583 A (FIG. 2)

However, in the case of the above-described deposition down type plasma CVD apparatus, the mask disposed on the substrate may thermally expand during film formation, which may cause poor adhesion with the substrate or impair mask accuracy. In the case of the deposition down method, there is also a problem that particles (dust particles) fall and adhere to the film formation surface (device surface).
On the other hand, in the case of a deposition CVD plasma CVD apparatus, the problem of particles does not occur, and the film formation quality can be improved. However, in the case of the technique described in Patent Document 3, since the mask frame (frame body that holds the periphery of the mask) protrudes below the electrode surface (substrate), the shape of the plasma discharge space in the vicinity between the upper and lower electrodes is There is a case where the plasma discharge space is not uniform (the plasma discharge space is curved as the distance from the opposed region of the upper and lower electrodes to the mask frame).

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a plasma type mask CVD apparatus that has high uniformity of film formation and can prevent the influence of particles.

In order to achieve the above object, a plasma type mask CVD apparatus of the present invention comprises a vacuum chamber, a lower cathode electrode and an upper anode electrode arranged in parallel in the vacuum chamber, and a lower surface of the upper anode electrode, respectively. And a mask frame for supporting a peripheral edge of the mask disposed through the substrate, and applying a voltage to the discharge space between the lower cathode electrode and the upper anode electrode to supply a source gas in the discharge space The plasma mask CVD apparatus for forming a film on the substrate by converting the plasma into a plasma, wherein a lower surface of the mask frame is flush with a lower surface of the mask in the vicinity of the discharge space, and the inner surface of the mask frame There is a space for accommodating the upper anode electrode and the substrate, and the mask, the substrate, and the upper anode electrode can be overlaid in this state.
With this configuration, the lower surface of the mask frame is flush with the lower surface of the upper anode electrode (the lower surface of the mask), and the discharge space in the vicinity of each electrode has a uniform shape (when separated from the opposing area of the upper and lower electrodes to the mask frame) However, the plasma discharge space extends in parallel with the surfaces of the upper and lower electrodes and is uniform, and the space is not curved. Therefore, the plasma state in the vicinity of the substrate is stabilized, and the film thickness distribution is uniform regardless of the position of the substrate.

Preferably, the mask is a tension mask, and the deflection due to the thermal expansion during film formation and the weight of the mask itself (hereinafter referred to as self-weight deflection) is smaller than the self-weight deflection during film formation of the substrate.
With such a configuration, the self-weight deflection of the mask during film formation can be suppressed by adjusting the tension of the mask to a predetermined strength or more. In addition, by making the self-weight deflection of the mask at the time of film formation smaller than the self-weight deflection at the time of film formation of the substrate, the mask deflection acts dominantly in the deflection when the mask and the substrate are superposed. Thus, the close contact state between the substrate and the mask can be satisfactorily maintained by utilizing the self-weight bending of the substrate. Accordingly, deformation of the superposed mask can be suppressed and the adhesion between the mask and the substrate can be improved, and the uniformity of the film formation rate on the substrate and the mask accuracy can be improved.

  According to the present invention, when performing plasma CVD using a mask, the uniformity of film formation on a substrate is high, and the influence of particles can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The plasma-type mask CVD apparatus according to the embodiment of the present invention can be the same as the apparatus described in Japanese Patent Application Laid-Open No. 2006-45583 except for the configuration peculiar to the present invention. These parts are denoted by the same reference numerals, and the description is appropriately cited (or omitted).

  FIG. 1 is an overall configuration diagram of a plasma type mask CVD apparatus according to an embodiment of the present invention. In this figure, a plasma mask CVD apparatus includes a vacuum chamber 1, a lower cathode electrode 3 and an upper anode electrode 2 arranged in parallel in the vacuum chamber, and a substrate 5 on the lower surface of the upper anode electrode 2. And a mask frame 50 having a rectangular frame shape that is coupled to the periphery of the mask 4. The mask frame 50 has a function of maintaining the shape of the mask 4 and reinforcing it.

A rotation mechanism 24 (consisting of a rotation drive source and a rotation shaft), an alignment mechanism 7, a camera unit 13, and a correction drive mechanism 26 are provided on the outer top of the vacuum chamber 1. The operation of these mechanisms is the same as that described in JP-A-2006-45583.
Then, two arm-like connecting portions 23 are connected to the mask frame 50 and extend upward, and the connecting portions 23 are connected to each other by a horizontal rod-like portion. One central axis extends upward from the center of the lateral bar-shaped portion of the continuous portion 23, the central axis is connected to the center of the rotating mechanism 24, and the mask frame 50 is suspended in the vacuum chamber 1.
Similarly, two arm-like connecting portions 29 extend upward from the upper surface of the upper anode electrode 2, and the connecting portions 29 are connected to each other by a horizontal bar-like portion. One central axis extends upward from the center of the lateral bar-shaped portion of the continuous portion 29, the central axis is connected to the center of the rotating mechanism 24, and the upper anode electrode 2 is suspended in the vacuum chamber 1.

Then, using the alignment mechanism 7 and the correction drive mechanism 26 as appropriate, first, the glass substrate 5 is positioned on the mask 4 attached to the mask frame 50 to superpose them, and then the upper anode electrode 2 is placed on the substrate 5 side. The upper anode electrode 2 and the mask frame 50 are fixed by a clamp (not shown) in a pressed (or close) state. As a result, the mask, the substrate, and the upper anode electrode are polymerized to enable film formation.
Note that the alignment of the substrate and the mask can also be performed in an alignment chamber provided as a separate chamber from the film formation chamber. In this case, the film can be formed in the same manner as described above by disposing the polymer at the fixed position of the mask frame in the film forming chamber in a state where the substrate and the mask are polymerized.
On the other hand, the support tube 19 extends downward from the lower surface of the lower cathode electrode 3 to hold the lower cathode electrode 3 in the vacuum chamber 1. A film-forming material gas (discharge gas) introduction tube (not shown) is arranged in the support tube 19, and a film-forming material gas (if necessary, further in the discharge space between the lower cathode electrode 3 and the upper anode electrode 2). Discharge gas) can be introduced. An exhaust port 22 connected to an evacuation system composed of a vacuum pump or the like is disposed below the vacuum chamber 1.
An oil circulation path (heating mechanism), which will be described later, is disposed above the upper anode electrode 2, and the temperature of the upper anode electrode 2 (and the substrate 5) is controlled by the heating oil introduced from the oil circulation unit 18.

The upper anode electrode 2 is grounded to form a ground electrode, and a power source 60 for supplying a high frequency voltage is capacitively connected to the lower cathode electrode 3 through an impedance matching circuit to form an RF electrode. Then, the substrate 5 is disposed on the lower surface of the upper anode electrode 2, a high frequency voltage is applied between the electrodes 2 and 3, and the film forming material gas introduced into the discharge space between the electrodes 2 and 3 is turned into plasma, CVD film formation is performed.
The film forming material is deposited on the substrate 5 through the opening of the mask 4 exposed on the lower surface of the mask frame 50, and the film formation along the mask pattern proceeds.

Next, a configuration around each electrode 2 and 3 will be described with reference to an enlarged view 2. The upper anode electrode 2 is composed of a rectangular lower member 2a and an upper member 2b, respectively, and the lower member 2a is exposed on the lower surface and functions as a substantial electrode. Inside the upper member 2b, oil circulation paths (heating mechanisms) 12 are arranged at equal intervals, and the entire upper anode electrode 2 is appropriately heated.
Here, the periphery of the lower member 2a is located inside the periphery of the upper member 2b, and a step is formed between the side end of the lower member 2a and the lower surface of the periphery of the upper member 2b. On the other hand, the mask frame 50 has a rectangular cross section, the inner diameter of the mask frame 50 is slightly larger than the outer diameter of the lower member 2a, and the thickness of the mask frame 50 is slightly smaller than the thickness of the lower member 2a. The mask 4 is coupled and attached by point welding using a laser beam such as YAG so that it is substantially flush with the lower surface of the mask frame 50 (on the same plane).
The mask frame 50 includes a mask frame main body 51 that is located on the inner side of the connecting portion 23 and holds the mask, and a mask frame side portion 52 that is located on the outer side of the connecting portion 23. The substantially functioning part is the mask frame main body 51, but these are collectively referred to as the mask frame 50 for convenience.

On the other hand, the upper surface of the lower cathode electrode 3 is provided with a gas blowing mechanism 11 in which a large number of holes 11a are arranged in a lattice pattern. Each hole 11a communicates with the inner space of the lower cathode electrode 3, and this inner space is supported by a support tube. 19 is connected to a film forming material gas (discharge gas) introduction pipe 15. In this way, the film forming material gas can be uniformly supplied onto the substrate 5.
An oil circulation path (heating mechanism) 12 similar to that in the case of the upper anode electrode 2 is disposed inside the lower cathode electrode 3, and heated oil flows in and out by the oil circulation portions 16 and 17. The temperature of the side cathode electrode 3 is controlled.

FIG. 3 shows the positional relationship between the mask frame 50, the upper anode electrode 2, and the substrate 5. In this figure, there is a space for accommodating the lower member 2a and the substrate 5 inside the mask frame 50. In this state, the mask, the substrate, and the upper anode electrode can be polymerized to form a film. At this time, the upper portion of the mask frame 50 is accommodated in the step portion described with reference to FIG.
In this way, the lower surface of the mask frame 50 is parallel to the lower surface of the electrode 2 (more precisely, the lower surface of the mask 4), and the discharge space 6 between the electrodes 2 and 3 becomes a uniform shape (from the upper and lower electrodes to the mask frame side). The plasma discharge space parallel to the surface of the upper and lower electrodes is uniformly formed and the plasma discharge space is not curved up and down), so that the plasma state in the vicinity of the substrate is stabilized, regardless of the position of the substrate. The film thickness distribution becomes uniform.

Returning to FIG. 2, it is preferable that the present invention also includes a plasma leakage prevention mechanism 8 similar to that described in Japanese Patent Laid-Open No. 2006-45583. The plasma leakage prevention mechanism 8 includes two insulating region forming bodies 9 that are parallel to the opposing surfaces of the electrodes 2 and 3, respectively.
The insulating region forming body 9 on the upper anode electrode 2 side is attached to the lower surface of the mask frame side portion 52 outside the connecting portion 23 and forms a frame surrounding the mask frame main body 51. Similarly, the insulating region forming body 9 on the lower cathode electrode 3 side forms a frame surrounding the lower cathode electrode 3.

Accordingly, the insulating region forming body 9 is opposed to and close to the opposing surfaces of the electrodes 2 and 3 and outside the discharge space 6, and an insulating region is formed at the outer peripheral position of the discharge space 6 so as to surround the space 6. The
Therefore, even if a voltage is applied to each of the electrodes 2 and 3, the film forming material gas is not converted into plasma in this insulating region, and leakage of plasma from the space 6 can be prevented. Further, the film forming material gas converted into plasma in the discharge space 6 is discharged to the alignment mechanism 7 side through the facing space 10 of the insulating region forming body 9 communicating with the space 6. At this time, the film forming material gas is discharged. The plasma disappears. Therefore, the plasma gas does not contaminate the alignment mechanism 7 or the like of the vacuum chamber 1.
Examples of materials that can be used for the insulating region forming body 9 include those described in JP-A-2006-45583.

<Tension mask>
It is preferable to use a tension mask as the mask 4, and it is more preferable that the self-weight deflection at the time of film formation is smaller than the self-weight deflection at the time of film formation of the substrate. The tension of the mask is not particularly limited as long as the mask can be prevented from being deformed by its own weight deflection. Preferably, the difference in distance between the surface of the substrate 5 and the upper surface of the lower cathode electrode 3 is a peripheral portion and a central portion ( 5% or less, and more preferably 3 to 2%. When the distance difference exceeds 5%, the film thickness of the deposited material varies depending on the position of the substrate. Here, since the difference in film thickness also affects the film quality, when the local sealing performance of the obtained element deteriorates or the film thickness is controlled based on the minimum film thickness portion, the film is formed. There is a problem that it is necessary to extend the time and the decrease in throughput becomes remarkable.
When the distance difference is 5% or less, the film formation rate on the substrate and the film quality uniformity, and hence the film quality uniformity and mask accuracy are improved. In particular, in the present invention, since the mask 4 is usually bonded and attached to the lower side of the mask frame 50, the mask is easily bent as compared with the case where the mask frame is supported from the lower side of the mask. It is. The tension applied to the mask can be determined by computer simulation, etc., taking into account the linear thermal expansion coefficient for the mask material, temperature during use, and mask size (thickness, weight, area). It is.
In the present invention, the self-weight deflection of the mask and the substrate during film formation can be a value determined by the above-described computer simulation. As a computer simulation method, for example, a material character can be input and calculated by a known CAE (Computer Aided Engineering: computer numerical analysis, simulation) analysis program or the like.

  Normally, after placing the substrate on the mask in the previous step of plasma CVD, the mask and the substrate are inverted and used for plasma CVD processing. According to the present invention employing the deposition method, such inversion is performed. Is no longer necessary.

1 is an overall configuration diagram of a plasma type mask CVD apparatus according to an embodiment of the present invention. It is the elements on larger scale of FIG. FIG. 4 is a diagram showing a positional relationship among a mask frame 50, an upper anode electrode 2, and a substrate 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Upper anode electrode 3 Lower cathode electrode 4 Mask 5 Substrate 50 Mask frame

Claims (2)

A vacuum chamber; a lower cathode electrode and an upper anode electrode arranged in parallel in the vacuum chamber; and a mask frame for supporting a peripheral edge of a mask arranged on a lower surface of the upper anode electrode through a substrate. And a plasma type mask CVD apparatus for forming a film on the substrate by applying a voltage to the discharge space between the lower cathode electrode and the upper anode electrode to convert the source gas in the discharge space into plasma. And
In the vicinity of the discharge space, the lower surface of the mask frame is flush with the lower surface of the mask and has a space for accommodating the upper anode electrode and the substrate inside the mask frame. A plasma-type mask CVD apparatus capable of overlaying a substrate and the upper anode electrode. 2. The plasma type mask CVD apparatus according to claim 1, wherein the mask is a tension mask, and the self-weight deflection at the time of film formation is smaller than the self-weight deflection of the substrate at the time of film formation.