JP4238643B2 - Electrode support structure for thin film forming equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrode support structure of a thin film forming apparatus using plasma CVD for uniformly forming a thin film of silicon or the like on a substrate.
[0002]
[Prior art]
Although solar cells are attracting attention and expected as a clean energy source, cost reduction is indispensable in order to achieve their widespread use. For this reason, a silicon film with a uniform film thickness can be formed on a large substrate with high efficiency. There is a strong demand for a thin film forming apparatus capable of mass production by forming silicon films on a plurality of substrates by a single operation. For the formation of thin films such as silicon films, parallel plate type (capacitive coupling type) plasma CVD devices have been put into practical use, but they are usually low in efficiency because only one substrate can be processed. There is a problem that the apparatus becomes very large when trying to process them simultaneously. In addition, there is a problem that the uniformity of the thickness of the thin film formed with the increase in the size of the substrate is remarkably lowered, and a solar cell having desired characteristics cannot be obtained.
[0003]
In order to produce a thin film with high film thickness uniformity, it is necessary to form plasma with a uniform density over the entire substrate, and various studies have been made for this purpose. However, in the parallel plate electrode system, it is not easy to form a uniform density plasma when the substrate is enlarged. That is, in the parallel plate type electrode, in order to form plasma with a uniform density, it is necessary to maintain the distance between the two electrodes with high precision over the entire substrate, but this is not easy, and the size of the substrate increases. It becomes even more difficult. In the parallel plate type electrode system, a self-bias potential is generated in the electrode due to the discharge between the electrode to which a high frequency is applied and the counter electrode and the film formation chamber wall at the ground potential, and thus the plasma density is distributed. There is a problem. Furthermore, when the electrode becomes large, a standing wave is generated on the surface thereof, and thus plasma may be distributed.
[0004]
Therefore, the plasma maintenance mechanism is completely different from that of the parallel plate type electrode method, and there are no problems such as inter-electrode distance accuracy and electrode self-bias inherent to the parallel plate type electrode method, and VHF is advantageous for high-speed film formation. A plasma CVD method using an inductively coupled electrode that can generate a high plasma density using a high frequency band has been proposed.
[0005]
However, for example, when the inductively coupled electrode having a ladder shape or a zigzag shape is enlarged in response to an increase in the size of the substrate, the current path is less likely to be uniform, and the current is partially localized in an unexpected place. There is a problem in that waves are generated, which makes it difficult to make the plasma density uniform, and it is difficult to cope with a large-area substrate with a conventional electrode structure.
[0006]
Therefore, a thin film forming apparatus that can efficiently form a silicon film having a uniform thickness on a large substrate without increasing the size of the apparatus, and can simultaneously improve the productivity by forming silicon films on a plurality of substrates simultaneously. As shown in FIGS. 5 and 6, this thin film forming apparatus has a plurality of rows (three rows in the example of FIG. 6) of inductively coupled electrode groups 3 </ b> A inside the partition walls 2 of the film forming chamber 1. They are arranged (in FIG. 5, six inductive coupling type electrodes 3 constitute a single row of inductive coupling type electrode group 3A).
[0007]
Each of the inductively coupled electrodes 3 is formed in a substantially U shape by a power feeding portion 3a and a grounding portion 3b, and the substantially U-shaped surfaces are arranged in the same plane with a predetermined interval. Thus, an electrode row corresponding to the width of the substrate 4 is formed.
[0008]
The tip of the power feeding portion 3a of each of the substantially U-shaped inductively coupled electrodes 3 is connected to a power feeding inner conductor of a power feeding connector 5 provided on the partition wall 2 in the upper part of the film forming chamber 1, and the power feeding inner conductor is a high frequency. The coaxial cable 7 connected to the power source 6 is connected to the core body side that supplies high-frequency power. The tip of the ground portion 3 b of each inductively coupled electrode 3 is grounded to the partition wall 2 by the ground conductor of the ground side connector 8 provided on the partition wall 2. Further, the outer conductor of the power supply side connector 5 is grounded to the partition wall 2, and this outer conductor is connected to the outer body side covering the core body of the coaxial cable 7, thereby providing a ground potential and a shield ground for high frequency power. Is supposed to do. At this time, a phase shifter (not shown) is arranged between the power supply side connector 5 and the high frequency power source 6 in order to supply the high frequency of the opposite phase to the power supply part 3a of the adjacent inductively coupled electrodes 3 and 3. Further, there is a type in which a waveform generator (not shown) is connected to the high frequency power source 6 so that desired AM modulation is applied to the high frequency power output from the high frequency power source 6.
[0009]
In the thin film forming apparatus, as shown in FIG. 5, an electrode array (inductive coupling electrode group 3A) in which inductive coupling electrodes 3 are arranged corresponding to the width of the substrate 4 is spaced at a predetermined interval as shown in FIG. A plurality of rows (three rows in the example of FIG. 6) are arranged, and the substrates 4 are arranged on both sides of each inductive coupling type electrode 3. With this configuration, a large number of substrates 4 (six in the example of FIG. 6) It is possible to improve the productivity by simultaneously forming a thin film thereon. The front wall 2a (the left side wall in FIG. 5) of the film forming chamber 1 is configured to be openable and closable. By opening the front wall 2a, the substrate 4 can be carried onto the substrate support base 9 or the substrate support base. 9 Can be taken out from the top.
[0010]
Further, the inside of the film forming chamber 1 is connected to a vacuum suction device 10 so that the inside of the film forming chamber 1 is vacuum sucked. For this reason, the film forming chamber 1 is configured to be airtight.
[0011]
Further, a gas supply source 11 is connected to the outside of the ground side connector 8, and a film of silane or the like is formed in the film forming chamber 1 through the inside of the ground portion 3 b formed by the pipe of the inductively coupled electrode 3. Therefore, the raw material gas 12 can be supplied.
[0012]
In the thin film forming apparatus shown in FIG. 5 and FIG. 6, the substrate 4 is disposed on both sides of the inductively coupled electrodes 3 arranged in a plurality of rows, the inside of the film forming chamber 1 is kept in vacuum by the vacuum suction device 10, and the gas When a source gas 12 such as silane is supplied from a supply source 11 and a high-frequency power is supplied from the high-frequency power source 6 to the inductively coupled electrode 3 in this state to generate plasma between the power supply unit 3a and the ground unit 3b, A uniform silicon thin film is formed on the surface of the substrate 4.
[0013]
As an example of the thin film forming apparatus as described above, there is Patent Document 1, for example.
[0014]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-69653 [0015]
[Problems to be solved by the invention]
However, in the conventional thin film forming apparatus as described above, since the lower end portion of the inductive coupling type electrode 3 is simply suspended and is not supported, the inductive coupling type electrode 3 does not fit within the same plane, but varies. Due to the difference in elongation in the longitudinal direction due to the difference in thermal expansion between the power feeding portion 3a and the grounding portion 3b of the electrode 3, it becomes difficult to maintain the respective intervals, leading to discharge unevenness and the like. It was.
[0016]
In view of such a situation, the present invention can eliminate variation by placing the electrodes in the same plane, and can maintain a constant distance between the power feeding portion and the grounding portion of the electrode, thereby preventing discharge unevenness and the like. An object of the present invention is to provide an electrode support structure for a thin film forming apparatus.
[0017]
[Means for Solving the Problems]
In the present invention, a plurality of electrodes each having a power feeding portion and a grounding portion extending through a partition wall and extending into a film forming chamber are arranged side by side so as to be aligned in the same plane, a substrate surface is opposed to an electrode array, and a thin film is formed on the substrate surface. An electrode support structure of a thin film forming apparatus for forming
Provided at the tip of the electrode is a restraining means for bundling the power feeding part and the grounding part of the electrodes arranged side by side while keeping the respective intervals and insulating so as to be slidable in the longitudinal direction of the electrode ,
The restraining means is
A stopper fitted to the tip of the electrode located at both ends of the electrode array;
A rail member disposed on both sides of the electrode array so as to extend in the electrode alignment direction and supported by the stopper;
An electrode support member disposed so as to be spanned between the rail members and supporting the power feeding portion and the grounding portion of the electrode slidably in the longitudinal direction of the electrode;
A spacer that is inserted between the electrode support members adjacent to each other and that keeps a distance between the power feeding portion and the grounding portion of the electrode;
The present invention relates to an electrode support structure of a thin film forming apparatus.
[0018]
According to the above means, the following operation can be obtained.
[0019]
When configured as described above, the tip of the inductively coupled electrode is not simply suspended, but a stopper fitted to the tip of the electrode located at both ends of the electrode row, and both sides of the electrode row. A rail member arranged to extend in the electrode alignment direction and supported by the stopper, and arranged to be spanned between the rail members and to support the power feeding portion and the ground portion of the electrode slidably in the electrode longitudinal direction. Since the electrode support member is supported by the restraining means that is inserted between the electrode support members adjacent to each other and that holds the gap between the electrode power supply portion and the ground portion , the same plane is provided. Even if there is a difference in expansion in the longitudinal direction of the electrode due to the difference in thermal expansion between the power feeding part and the grounding part of the inductive coupling type electrode, the force is applied to the inductive coupling type electrode. Act Each interval it is possible to hold constant, it becomes possible to prevent the discharge unevenness.
[0020]
In the electrode support structure of the thin film forming apparatus, the electrode supporting member, formed in the longitudinal direction to the bisected halves of the rail member, fixing one of the half body between the rail members, the other half The split body is slidably disposed in the longitudinal direction of the rail member, and a spacer is fitted between the electrode support members adjacent to each other so that the other half body is integrated with the one half body. It may be configured to sandwich the electrode.
[0021]
In this way, the restraining means can be easily attached and removed without using a special tool or the like, and maintenance and inspection of the inductively coupled electrode can be easily performed.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described together with illustrated examples.
[0023]
1 to 4 show an example of an embodiment of the present invention. In the figure, the same reference numerals as those in FIGS. 5 and 6 denote the same components, and the basic configuration is shown in FIGS. 6 is the same as the conventional one shown in FIG. 6, but the feature of this example is that it is arranged in parallel at the tip (lower end) of the inductively coupled electrode 3 as shown in FIGS. This is in that a restraining means 13 is provided for bundling the power feeding portion 3a and the grounding portion 3b of the inductively coupled electrode 3 while keeping the distance L and insulating them so as to be slidable in the electrode longitudinal direction Y.
[0024]
In the case of the illustrated example, the restraining means 13 includes a stopper 14 fitted to the tip of the grounding portion 3b of the inductively coupled electrode 3 located at both ends of the electrode row, and an electrode alignment direction on both sides of the electrode row. A rail member 15 that extends to X and is supported by the stopper 14, and a power supply portion 3 a and a grounding portion 3 b of the inductively coupled electrode 3 that are arranged so as to be spanned between the rail members 15 and electrodes An electrode support member 16 that is slidably supported in the longitudinal direction Y, and a spacer 17 that is fitted between the electrode support members 16 adjacent to each other and that maintains a distance L between the power feeding portion 3a and the grounding portion 3b of the inductively coupled electrode 3 It has the structure provided with.
[0025]
As shown in FIG. 3, a square hole portion 18 extending in a direction perpendicular to the electrode alignment direction X is formed at the tip of the grounding portion 3b of the inductively coupled electrode 3, and the stopper 14 is formed of the square hole portion. 18 and a stepped square bar-shaped member having stepped portions 22 formed on the upper surfaces of both ends. The stopper 14 is fitted into the square hole portion 18, and in this state, as shown in FIGS. As shown, the rail member 15 is placed on the upper surface of the stopper 14, and the lower end edge of the rail member 15 is engaged with the step portion 22.
[0026]
Further, as shown in FIG. 4, the electrode support member 16 is divided into two in the longitudinal direction of the rail member 15 (electrode alignment direction X), and a groove portion 23 that engages with the outer peripheral surface of the tip of the inductively coupled electrode 3 is provided in a recessed manner. The halves 16a and 16b made of ceramics, etc. are formed, and the other halved body 16b is fixed with a fastening member 24 such as a bolt and a nut so as to hang one half body 16a between the rail members 15. The rail member 15 is slidably disposed in the longitudinal direction, and a spacer 17 is inserted between the electrode support members 16 adjacent to each other, whereby the other half body 16b is integrated with the one half body 16a. The outer peripheral surface of the tip of the inductively coupled electrode 3 is sandwiched.
[0027]
As shown in FIGS. 1 and 4, the spacer 17 has a T-shaped cross section, and its tip has a slightly sharpened shape so that it can be easily inserted between the electrode support members 16 adjacent to each other. In addition, the upper and lower corners of the halves 16a and 16b of the electrode support member 16 are chamfered.
[0028]
In addition, a closing member 27 is provided at one open end (right end in the example of FIG. 1) between the rail members 15 on which the other halved body 16b of the electrode support member 16 is disposed. The fastening member 28 is attached, and the spacer 17 can be inserted between the closing member 27 and the other half body 16b of the electrode support member 16 which is movable.
[0029]
Furthermore, as shown in FIGS. 1 and 2, the tips of the power feeding portion 3 a and the grounding portion 3 b of the inductively coupled electrode 3 are electrically connected by a metal connector 29, and the connector 29 Is connected between the mounting portion 30 and the mounting portion 30 that can be easily attached / detached by being hooked on the hole 25a formed in the power feeding portion 3a and the hole 25b formed in the grounding portion 3b. The flexible part 31 is configured.
[0030]
Next, the operation of the illustrated example will be described.
[0031]
When attaching the restraining means 13 to the inductively coupled electrode 3, first, as shown in FIG. 3, the stepped square bar-shaped stoppers 14 are provided at the corners of the grounding portion 3b of the inductively coupled electrode 3 positioned at both ends of the electrode array. Fit into the hole 18.
[0032]
Subsequently, as shown in FIG. 4, the groove portions 23 of the halves 16 a and 16 b of the electrode support member 16 are engaged with the outer peripheral surfaces of the power feeding portions 3 a and the grounding portions 3 b of the inductively coupled electrodes 3. The rail members 15 are arranged on both sides of the electrode rows so as to extend in the electrode alignment direction X, and one half member 16a is fixed with a fastening member 24 such as a bolt and a nut so as to span between the rail members 15, and the other The half member 16b is slidable in the longitudinal direction of the rail member 15, and in this state, the rail member 15 is supported on the stopper 14 as shown in FIGS. Furthermore, a closing member 27 such as a bolt and a nut is provided at one open end (the right end in the example of FIG. 1) between the rail members 15 on which the other halved body 16b that is movable of the electrode support member 16 is disposed. The fastening member 28 is used for attachment. As shown in FIG. 2, the rail member 15 and the electrode support member 16 are supported by the stopper 14 by supporting the weight of the rail member 15 and the electrode support member 16 and the like from the partition wall 2 above the film forming chamber 1. The lower end edge of the opposing rail member 15 is engaged with the step portion 22 of the stopper 14 so that the stopper 14 is sandwiched between the rail members 15 and does not fall off.
[0033]
Thereafter, the spacer 17 having a T-shaped cross section is placed between the other half-divided body 16b and the other half-divided body 16a of the electrode support members 16 adjacent to each other and the other half-position located at the end of the rail member 15. When the split member 16b is inserted between the closing member 27, the other half member 16b is integrated with the one half member 16a, and the power feeding part 3a and the grounding part 3b of each inductively coupled electrode 3 are integrated. The outer peripheral surface of the tip end part is slidably held in the longitudinal direction Y of the electrode by the halves 16a and 16b.
[0034]
As a result, the tip portion of the inductively coupled electrode 3 is not simply suspended, but is supported by the restraining means 13, so that it does not vary within the same plane, and the inductively coupled electrode 3 3, even if a difference in expansion in the electrode longitudinal direction Y occurs due to a difference in thermal expansion between the power feeding portion 3 a and the grounding portion 3 b, the respective distances L are set without applying an excessive force to the inductively coupled electrode 3. It becomes possible to keep it constant, and discharge unevenness can be prevented.
[0035]
Further, since the restraining means 13 can be easily attached and removed without using a special tool or the like, maintenance and inspection of the inductively coupled electrode 3 can be easily performed.
[0036]
In this way, the inductive coupling type electrode 3 can be accommodated in the same plane to eliminate variations, and the distance L between the power feeding part 3a and the grounding part 3b of the inductive coupling type electrode 3 can be kept constant. Can be prevented.
[0037]
In addition, the electrode support structure of the thin film forming apparatus of the present invention is not limited to the above-described illustrated examples, and it is needless to say that various changes can be made without departing from the gist of the present invention.
[0038]
【The invention's effect】
As described above, according to the electrode support structure of the thin film forming apparatus of the present invention, the electrodes can be accommodated in the same plane to eliminate variations, and the distance between the electrode power supply unit and the grounding unit can be kept constant. In addition, an excellent effect of preventing discharge unevenness and the like can be achieved.
[Brief description of the drawings]
FIG. 1 is a side sectional view of an example of an embodiment for carrying out the present invention.
2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a perspective view showing a stopper of a restraining means in an example of an embodiment for carrying out the present invention.
FIG. 4 is a perspective view showing a rail member and an electrode support member of a restraining means in an example of an embodiment for carrying out the present invention.
FIG. 5 is a side sectional view of an example of a conventional thin film forming apparatus.
6 is a front sectional view of an example of a conventional thin film forming apparatus, corresponding to the view taken along the line VI-VI in FIG. 5;
[Explanation of symbols]
1 Deposition chamber 2 Partition 3 Inductively coupled electrode (electrode)
3a Power feeding portion 3b Grounding portion 4 Substrate 13 Restraining means 14 Stopper 15 Rail member 16 Electrode support member 16a Half split body 16b Half split body 17 Spacer 23 Groove L interval X Electrode alignment direction Y Electrode longitudinal direction

Claims (2)

A thin film in which a plurality of electrodes each having a power feeding portion and a grounding portion extending through the partition wall and extending into the film formation chamber are aligned in the same plane, the substrate surface is opposed to the electrode row, and a thin film is formed on the substrate surface An electrode support structure of a forming apparatus,
Provided at the tip of the electrode is a restraining means for bundling the power feeding part and the grounding part of the electrodes arranged side by side while keeping the respective intervals and insulating so as to be slidable in the longitudinal direction of the electrode ,
The restraining means is
A stopper fitted to the tip of the electrode located at both ends of the electrode array;
A rail member disposed on both sides of the electrode array so as to extend in the electrode alignment direction and supported by the stopper;
An electrode support member disposed so as to be spanned between the rail members and supporting the power feeding portion and the grounding portion of the electrode slidably in the longitudinal direction of the electrode;
A spacer that is inserted between the electrode support members adjacent to each other and that keeps a distance between the power feeding portion and the grounding portion of the electrode;
Electrode support structure of the thin film forming apparatus characterized in that it comprises a. The electrode support member is formed of a half that is divided in the longitudinal direction of the rail member, one half is fixed between the rail members, and the other half is slidable in the longitudinal direction of the rail member. 2. The structure according to claim 1 , wherein a spacer is inserted between the electrode support members adjacent to each other so that the other half is integrated with the other half to sandwich the electrode. Electrode support structure for thin film forming apparatus.

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