JP2012107303A - Sputtering film deposition device and solar battery manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sputtering film deposition device that can efficiently form a thin film having appropriate characteristics, and to provide a solar battery manufacturing apparatus.SOLUTION: The sputtering film deposition device includes a substrate 10 as a film deposition object, a target 23 as a cathode electrode that is arranged opposite to the substrate 10, and an anode electrode 24 arranged between the substrate 10 and target 23, in a reaction chamber 21, wherein the anode electrode 24 has a comb-teeth-like shape and is arranged in such a manner that comb-teeth-like gaps are projected to the deposition surface. The solar battery manufacturing apparatus is equipped with the sputtering device.

Description

  The present invention relates to a sputtering film forming apparatus and a solar cell manufacturing apparatus.

  Sputtering, which is one of thin film formation techniques, is widely used for forming metal thin films, transparent conductive films, semiconductor films, and the like. In the sputtering method, argon gas, helium gas, neon gas, nitrogen gas, etc. are introduced into the evacuated reaction chamber, and a DC high voltage is applied between the substrate and the target to cause ionized atoms (such as Ar atoms) to collide with the target. In this method, the target constituent atoms (sputtered particles) that are blown off are attached to the substrate to form a thin film. As one of sputtering methods, there is a magnetron sputtering method. The magnetron sputtering method is a method in which a magnetic field is generated on the surface of a target to perform sputtering. The plasma density is increased by the effect of capturing electrons by the magnetic field, and the sputtering rate can be increased.

  FIG. 4 is a schematic configuration diagram of a conventionally used sputtering apparatus. In this sputtering apparatus, a substrate holder 3 for placing a substrate 2 to be deposited is placed in a reaction chamber 1. Further, a target 5 serving as a cathode electrode is disposed opposite to the substrate 2 placed on the substrate holder 3, and an anode electrode 4 is disposed between the substrate 2 and the target 5. A magnetic field generating means 6 is disposed on the back surface of the target 5.

  As the anode electrode 4 of the sputtering apparatus, as shown in FIG. 5, one obtained by connecting a pair of rod-like anode bars 4a via a connecting shaft 4b is widely used.

  Patent Documents 1 and 2 disclose a sputtering film forming apparatus in which an anode electrode is meshed.

JP 63-121653 A JP-A-5-209265

  In the sputtering film forming apparatus, by disposing the anode electrode between the target and the substrate, plasma discharge between the anode electrode and the target is stabilized, and furthermore, the substrate is not easily exposed to plasma during film formation. Therefore, a thin film with good characteristics can be formed. However, since some of the sputtered particles from the target are blocked by the anode electrode, there are problems that the loss of the target increases, the film formation time increases, and the film formation efficiency is inferior.

  Accordingly, an object of the present invention is to provide a sputtering film forming apparatus and a solar cell manufacturing apparatus capable of efficiently forming a thin film having good characteristics.

  In achieving the above object, a sputtering film forming apparatus of the present invention includes a substrate to be formed in a reaction chamber, a target to be a cathode electrode disposed opposite to the substrate, the substrate and the target. And an anode electrode disposed between the anode electrode and the anode electrode, the anode electrode has a comb-like shape, and the comb-like gap portion is arranged to be projected onto the film-forming surface. It is characterized by.

  The sputtering film forming apparatus of the present invention is preferably a magnetron sputtering film forming apparatus.

  The sputtering film forming apparatus of the present invention has a magnetic field generating means on the opposite side of the target from the anode electrode, and a moving table for reciprocating the anode electrode and the magnetic field generating means in parallel with the substrate surface is provided. It is preferable that

  Moreover, the solar cell manufacturing apparatus of this invention is equipped with the said sputtering film-forming apparatus, It is characterized by the above-mentioned.

  According to the present invention, the reaction chamber includes a substrate to be deposited, a target to be a cathode electrode disposed to face the substrate, and an anode electrode disposed between the substrate and the target. In the sputtering film forming apparatus, the anode electrode has a comb-like shape, and the comb-like gap portion is arranged in the reaction chamber so as to be projected onto the film-forming surface. The film formation surface can be reached through the interdigital gap without being blocked by the anode electrode. For this reason, the loss of the target is reduced, and a thin film with good film quality can be formed in a short time.

It is the schematic of the solar cell manufacturing apparatus provided with the sputtering film-forming apparatus of this invention. It is the schematic of the sputtering film-forming apparatus of this invention. It is the schematic of the anode electrode of the sputtering film-forming apparatus of this invention. It is the schematic of the conventional sputtering film-forming apparatus. It is the schematic of the anode electrode of the sputtering film-forming apparatus.

  In the present invention, the “substrate to be deposited” is not particularly limited, and a conventionally known substrate can be used. For example, from materials such as polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polyarylate (PAR), polyamideimide (PAI), polybenzimidazole (PBI), polysulfone (PSF), etc. Examples thereof include a flexible substrate, a glass substrate, and a stainless steel substrate. As the type of substrate, a flexible substrate is preferable. By using a flexible substrate, film formation by a roll-to-roll method is possible, and film formation can be performed with high productivity. Hereinafter, the case where a flexible substrate is used as a substrate material will be described as an example.

  FIG. 1 is a schematic view showing an embodiment of a solar cell manufacturing apparatus provided with the sputtering film forming apparatus of the present invention.

  As shown in FIG. 1, this solar cell manufacturing apparatus includes an unwinding chamber 12 in which an unwinding roll 11 that winds up a substrate 10 is accommodated, and a winding chamber in which an unwinding roll 13 that winds up the substrate 10 is accommodated. 14 and a sputtering film forming apparatus 20 disposed between the unwinding chamber 12 and the winding chamber 14 along the transport direction of the substrate 10 (the arrow direction in the drawing).

  The unwinding chamber 12 and the winding chamber 14 are each provided with a plurality of guide rollers 15 and 16 (two in this embodiment) for guiding the substrate 10 and making the tension applied to the substrate 10 uniform. ing.

  In the sputtering film forming apparatus 20, a substrate holder 22 for installing the substrate 10 is disposed in a reaction chamber 21 in which a gas introduction port 21a and an exhaust port 21b are formed. A target 23 serving as a cathode electrode is disposed facing the substrate holder 22, and an anode electrode 24 is disposed between the substrate 10 and the target 23. That is, the anode electrode 24 and the target 23 are arranged in this order at a predetermined interval from the substrate holder 22.

  Referring to FIGS. 2 and 3, the anode electrode 24 is composed of a pair of anode bars 24 a and 24 a processed into a comb shape, and the ends of the anode bars 24 a are joined to each other via a connecting shaft 24 b. And integrated. A plurality of comb teeth 24c are protruded from the pair of anode bars 24a and 24a so as to face each other at a predetermined interval L. The anode electrode 24 can be reciprocated in parallel with the substrate 10 in synchronization with a magnetic field generator 25 described later by a movable means (not shown).

  The comb teeth 24c of the anode bar 24a are preferably 10 mm or more in length and are formed at intervals of 5 to 10 mm. The length of the comb teeth 24c is more preferably 20 to 40 mm. If the length of the comb teeth 24c is less than 10 mm, it is insufficient as an anode electrode, and it is necessary to design the length so as not to enter the magnetic field of the magnet. Further, when the interval between the comb teeth 24c is less than 5 mm, the sputtered particles may be blocked by the anode electrode 24. When the distance exceeds 10 mm, the sputter particles are insufficient as the anode electrode.

  The distance L between the comb teeth 24c of each anode bar 24a is designed so that the comb teeth do not enter the magnetic field of the magnet.

  The ratio of the area of the voids in the total area viewed from the planar direction of the anode electrode 24 (hereinafter referred to as “void ratio”) is preferably 40% or more. If the porosity is less than 40%, a sufficient effect cannot be obtained.

  A magnetic field generator 25 is disposed on the opposite side of the target 23 from the substrate 10.

  In the magnetic field generator 25, the first magnet 27a and the second magnet 27b are alternately arranged on the support plate 26 at a predetermined interval, and the target 23 of the first magnet 27a and the second magnet 27b. Each side facing is opposite in polarity. In this embodiment, the magnetic poles on the target 23 side of the first magnet 27a form an N pole, and the magnetic poles on the target 23 side of the second magnet 27b form an S pole. The movable means 28 allows the anode electrode 24 c and the magnetic field generator 25 to reciprocate in parallel with the target 23 in synchronization.

  Next, the operation when forming a film on the surface of the substrate 10 using this solar cell manufacturing apparatus will be described.

The substrate 10 is pulled out from the unwinding roll 11 and guided to the sputtering film forming apparatus 20.
In the sputtering film forming apparatus 20, after the inside of the reaction chamber 21 is evacuated, a sputtering gas such as argon gas, helium gas, neon gas, nitrogen gas or the like is introduced from the gas introduction port 21a, and the reaction chamber 21 has a constant gas pressure. Adjust to. The gas pressure in the reaction chamber 21 is preferably 0.01 to 5 Pa. When the gas pressure in the reaction chamber 21 is stabilized, a negative DC voltage or a high-frequency voltage is applied to the target 23 with the anode electrode 24 grounded. On the other hand, a magnetic field is generated from the first magnet 27 a to the second magnet 27 b through the target 23, and an arc-shaped magnetic field is formed on the surface side of the target 23. Then, plasma is generated between the anode electrode 24 and the target 23. As a result, the sputtering gas is ionized, the ionized atoms collide with the target 23, and the target constituent atoms (sputtered particles) blown off adhere to the substrate 10 through the comb-like gap portion of the anode electrode 24. As a result, a thin film is formed. Further, since plasma is generated between the anode electrode 24 and the target 23, the substrate 10 is not directly exposed to the plasma, so that a thin film with good film quality can be formed.

  During sputtering, the movable electrode 28 causes the anode electrode 24 and the magnetic field generator 25 to reciprocate in the horizontal direction in conjunction with each other. Thereby, the target 23 is eroded as uniformly as possible, and a uniform thin film is formed on the substrate 10.

  In this way, after a thin film having a predetermined thickness is formed on the surface of the substrate 10, the film forming process is completed and the film is wound up by the winding roll 13.

  In this sputtering film forming apparatus, the anode electrode 24 has a plurality of comb teeth 24c, and a gap portion of the comb teeth 24c is projected onto the film formation surface (when the anode electrode 24 is viewed from the plane direction, the gap The sputtered particles from the target 23 are not easily blocked by the anode electrode 24 and reach the film formation surface through the gap portions of the comb teeth 24c. For this reason, the loss of the target is reduced, and a thin film with good film quality can be formed in a short time. Moreover, since the contamination by the sputtered particles of the anode electrode 24 can be suppressed, the maintenance cost can be reduced.

  Hereinafter, the effects of the present invention will be described using examples and comparative examples. In the following examples and comparative examples, Ar was used as the sputtering gas, a flexible plastic film was used as the substrate, and ITO was used as the target.

Example 1
The thin film was formed in the board | substrate 10 using the solar cell manufacturing apparatus shown in FIG. As shown in FIG. 3, the anode bar 24 a having 30 mm-long comb teeth 24 c formed at intervals of 5 mm is used as the anode electrode 24. What was connected by the connection shaft 24b so that it might be set to 150 mm (50% of porosity) was used.
The unwinding roll 11 and the winding roll 13 are operated, the film formation surface of the substrate 10 is disposed in the reaction chamber 21, the inside of the reaction chamber 21 is evacuated, a sputtering gas is supplied, and the gas pressure is 0.7 Pa. It was. Then, a 200 V DC voltage was applied to the target to generate plasma, and target constituent atoms were attached to the surface of the substrate, and sputtering was performed for 5 minutes. A uniform thin film having a thickness of 100 nm was formed on the substrate surface.

(Example 2)
In Example 1, as the anode electrode 24, an anode bar 24a in which comb teeth 24c having a length of 30 mm are formed at intervals of 5 mm is used, and an abutment interval L of the comb teeth 24c between the anode bars is 150 mm. Sputtering was carried out for 2 minutes in the same manner as in Example 1 except that a material connected by a connecting shaft (porosity 50%) was used. A uniform thin film having a thickness of 60 nm was formed on the substrate surface.

(Comparative Example 1)
In Example 1, as shown in FIG. 5, a plate-like anode bar 4a having a length of 1500 mm, a width of 10 mm, and a thickness of 2 mm is used as the anode electrode 4, and the connecting shaft is set so that the interval between the anode bars 4a is 150 mm. Sputtering was carried out for 5 minutes in the same manner as in Example 1 except that the one formed by connecting the above was used. A thin film having a thickness of 50 nm was formed on the substrate surface.

10: substrate 11: unwinding roll 12: unwinding chamber 13: winding roll 14: winding chamber 15, 16: guide roller 20: sputtering film forming apparatus 21: reaction chamber 21a: gas introduction port 21b: exhaust port 22: Substrate holder 23: target 24: anode electrode 24a: anode bar 24b: connecting shaft 25: magnetic field generator 26: support plate 27a, 27b: magnet 28: movable means

Claims (4)

In a sputtering film forming apparatus, comprising: a substrate to be deposited in a reaction chamber; a cathode electrode target disposed opposite to the substrate; and an anode electrode disposed between the substrate and the target. ,
The sputtering film-forming apparatus, wherein the anode electrode has a comb-like shape, and the comb-like gap portion is arranged to be projected onto the film-forming surface.   The sputtering film forming apparatus according to claim 1, wherein the sputtering film forming apparatus is a magnetron sputtering film forming apparatus.   3. The moving table according to claim 1, further comprising a magnetic field generating unit on a side opposite to the anode electrode of the target, and a moving table for reciprocating the anode electrode and the magnetic field generating unit in parallel with the substrate surface. The sputtering film-forming apparatus of description.   The solar cell manufacturing apparatus provided with the sputtering film-forming apparatus in any one of Claims 1-3.