WO2011145430A1

WO2011145430A1 - Plasma device

Info

Publication number: WO2011145430A1
Application number: PCT/JP2011/059923
Authority: WO
Inventors: 敦史庄司
Original assignee: シャープ株式会社
Priority date: 2010-05-18
Filing date: 2011-04-22
Publication date: 2011-11-24
Also published as: JP2013152960A

Abstract

A plasma device is provided with: a housing, and an electrode part that contains a pair of electrodes (150, 160), between which a substrate (200) is sandwiched, said electrodes being disposed so as to face each other with a space therebetween. The housing has a window (380) on a side through which at least the substrate between the pair of electrodes (150, 160) of the electrode part can be viewed from the outside. The window (380) is impermeable to ultraviolet rays generated by plasma. With this configuration, the release of ultraviolet rays outside of the device can be minimized, and the substrate (200) being processed between the electrodes can be viewed.

Description

Plasma device

The present invention relates to a plasma apparatus for plasma processing a workpiece such as a substrate.

Japanese Patent Application Laid-Open No. 2009-48882 (Patent Document 1) is a prior art document that discloses the presence or absence of plasma discharge and a plasma apparatus that can monitor discharge abnormality. In the plasma apparatus described in Japanese Patent Laid-Open No. 2009-48882 (Patent Document 1), a window portion for visually confirming the inside of the processing chamber is provided.

FIG. 5 is a perspective view showing an external appearance of a conventional plasma apparatus. As shown in FIG. 5, in a plasma CVD (Chemical Vapor Deposition) apparatus 100 that is a conventional plasma apparatus, a casing including an opening / closing part 110 and a main body part 120 is placed on a base 140. A window portion (not shown) is provided on the back surface 130 of the housing. The opening / closing part 110 is opened and closed in the direction indicated by the arrow, and the substrate as the object to be processed is taken in and out.

FIG. 6 is a cross-sectional view showing a configuration of a conventional plasma apparatus. As shown in FIG. 6, an electrode portion including a pair of electrodes is arranged in a processing chamber 190 inside the housing. The electrode unit includes a lower electrode 150 on which the substrate 200 is placed on an upper surface, and an upper electrode 160 disposed to face the lower electrode 150 with a predetermined distance L therebetween.

The lower electrode 150 is placed so as to straddle the shelf 151 formed of a plurality of pins attached to the inner wall of the main body 120 of the housing. A heater 170 is provided inside the lower electrode 150. The lower electrode 150 is grounded.

The upper electrode 160 has openings (not shown) formed in the inside and the lower surface, and plasma generating gas is discharged from the openings. A gas pipe 161 to which a plasma generating gas is supplied is connected to the side surface of the upper electrode 160. The upper electrode 160 is connected to a wiring (not shown) to which high frequency power is supplied. The upper electrode 160 is placed so as to straddle the shelf 162 made of a plurality of pins attached to the inner wall of the main body 120 of the housing.

The plasma generation gas is discharged from the upper electrode 160 while the inside of the processing chamber 190 is exhausted by an exhaust unit (not shown), so that the pressure inside the processing chamber 190 is kept constant. Plasma is generated between the upper electrode 160 and the lower electrode 150 by applying a voltage between the upper electrode 160 and the lower electrode 150 while being heated by the heater 170.

In order to process the substrate 200 uniformly, the distance L between the upper electrode 160 and the lower electrode 150 needs to be constant over the entire surface of the electrode. When the interval L varies, plasma may not be generated in a part between the electrodes. In this case, the processing of the substrate 200 becomes uneven, and the processed substrate 200 becomes a defective product.

As one of the causes of the variation in the interval L, there is a breakage such as deformation or breakage in a part of the plurality of pins constituting the shelf 151 or the shelf 162. Since the inside of the plasma CVD apparatus 100 is exposed to plasma at a high temperature, the pins may be broken during the processing of the substrate 200. In that case, the fixing of the upper electrode 160 or the lower electrode 150 becomes unstable, and the distance L between the upper electrode 160 and the lower electrode 150 changes locally.

FIG. 7 is a perspective view showing a state of a substrate put into a conventional plasma apparatus. As shown in FIG. 7, the substrate 200 put into the plasma CVD apparatus 100 is covered with a substrate support plate made of ceramics.

Specifically, the upper substrate support plate 210 is disposed on the upper surface side of the substrate 200 and the lower substrate support plate 220 is disposed on the lower surface side of the substrate 200 on both opposing sides constituting the edge of the substrate 200. Is done. Upper substrate support plate 210 and lower substrate support plate 220 are fixed by bolts 250 and nuts (not shown).

Also, the upper substrate support plate 230 is disposed on the upper surface side of the substrate 200 and the lower substrate support plate 240 is disposed on the lower surface side of the substrate 200 in both of the other opposing sides constituting the edge of the substrate 200. Upper substrate support plate 230 and lower substrate support plate 240 are fixed by bolts 250 and nuts (not shown).

In order to process the substrate 200 uniformly in the plasma CVD apparatus 100, it is necessary to fix the substrate 200 horizontally. When the vertical position of the substrate 200 varies, the distance between the electrode and the substrate 200 varies, and the plasma reaction state cannot be made constant over the entire surface of the substrate 200.

When the substrate 200 is processed in the plasma CVD apparatus 100, the bolts and nuts fixing the substrate support plate may be damaged because they are exposed to plasma in a high temperature state. In this case, the substrate 200 is not sufficiently fixed, and the substrate 200 is displaced or deflected. As a result, the processing of the substrate 200 becomes uneven, and the processed substrate 200 becomes a defective product.

In the plasma processing apparatus, arcing may occur during plasma processing due to various factors such as insulation failure, voltage application failure, and vacuum degree failure. In this case, a by-product generated by arcing may adhere to the substrate 200 and become a defective product.

FIG. 8 is a side view of a conventional plasma apparatus as viewed from the back side. As shown in FIG. 8, a window portion 180 made of transparent glass for visually recognizing the processing chamber is provided on the lower surface 130 side of the conventional plasma CVD apparatus 100.

JP 2009-48882 A

As described above, in the plasma apparatus, a situation in which an abnormality can be confirmed by visually recognizing a positional deviation or the like occurs during plasma processing. However, since ultraviolet rays are generated from the plasma, the window portion made of transparent glass provided in the conventional plasma apparatus has a place other than between the electrodes in the processing chamber in order to suppress the ultraviolet rays emitted from the window portion to the outside. It could be visually recognized.

The present invention has been made in view of the above-described problems, and provides a plasma device that can visually recognize between electrodes on which an object to be processed is processed while suppressing ultraviolet rays from being emitted outside the device. The purpose is to provide.

The plasma apparatus according to the present invention is a plasma apparatus for plasma processing an object to be processed. The plasma apparatus includes a housing and an electrode portion including a pair of electrodes that are disposed to face each other with a workpiece interposed therebetween in the housing. The housing has a window part on the side surface, through which at least a pair of electrodes can be visually recognized from the outside. The window part is impermeable to ultraviolet rays generated from the plasma.

In one embodiment of the present invention, the window portion includes a transparent body that transmits visible light and an ultraviolet light transmission preventing member applied to the transparent body.

In one embodiment of the present invention, the window portion includes a transparent body that transmits visible light, and an ultraviolet transmission preventing member that is dispersed and contained in the transparent body.

Preferably, the transparent body includes fine ceramics.
In one form of this invention, a transparent body contains AlON.

In one embodiment of the present invention, the ultraviolet light transmission preventing member includes a photosensitive material that develops color upon receiving ultraviolet light.

Preferably, the photosensitive material is a photochromic compound.
In one form of this invention, the said ultraviolet-ray transmission prevention member contains the wavelength conversion material which light-emits visible light in response to an ultraviolet-ray.

Preferably, the wavelength conversion material is a nanoparticle phosphor.

According to the present invention, it is possible to visually recognize between the electrodes where the object to be processed is processed while suppressing the emission of ultraviolet rays to the outside of the apparatus.

It is the side view which looked at the plasma CVD apparatus which concerns on one Embodiment of this invention from the back side. It is sectional drawing which shows typically the structure of the window part of the embodiment. It is sectional drawing which shows typically the structure of the window part of the 1st modification of the embodiment. In the plasma CVD apparatus which concerns on the embodiment, it is the side view which looked at the state which is plasma-processing from the back side. It is a perspective view which shows the external appearance of the conventional plasma apparatus. It is sectional drawing which shows the structure of the conventional plasma apparatus. It is a perspective view which shows the state of the board | substrate thrown into the conventional plasma apparatus. It is the side view which looked at the conventional plasma apparatus from the back side.

Hereinafter, an embodiment of a plasma apparatus according to the present invention will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated. Note that a plasma CVD apparatus is described as a plasma apparatus; however, the plasma apparatus is not limited to this, and the present invention can be applied to a plasma apparatus that processes an object to be processed using plasma.

FIG. 1 is a side view of a plasma CVD apparatus according to an embodiment of the present invention as seen from the back side. As shown in FIG. 1, in the plasma CVD apparatus 300 according to one embodiment of the present invention, a window 380 is formed on the back surface 330 of the main body 320 of the housing. Since other configurations are similar to those of conventional plasma CVD apparatus 100, description thereof will not be repeated.

The plasma CVD apparatus 300 has a housing in which a processing chamber 390 in which a substrate 200 as an object to be processed is subjected to plasma processing is formed. The processing chamber 390 in the housing is provided with an electrode portion including a pair of the upper electrode 160 and the lower electrode 150 which are arranged to face each other with a space therebetween with the substrate 200 interposed therebetween. In the plasma CVD apparatus 300 of this embodiment, the electrode part includes a pair of electrodes, but the number of electrode pairs is not limited to this, and the electrode part may include a plurality of electrode pairs.

A window portion 380 that can visually recognize at least a pair of electrodes of the electrode portion from the outside is formed on the side surface on the back surface 330 side of the main body portion 320 constituting the housing. In the present embodiment, the window portion 380 is provided in the entire portion other than the peripheral portion of the back surface 330 in order to make the entire electrode portion visible.

However, the window portion 380 is provided at a position corresponding to the position between the upper electrode 160 and the lower electrode 150 so that only the region between the upper electrode 160 and the lower electrode 150 where the substrate 200 is processed can be visually recognized. May be.

The opening / closing part of the housing and the main body part 320 are made of metal such as iron. The window 380 is made of a material that is impermeable to ultraviolet rays generated from plasma and is transmissive to visible light. Moreover, the material which comprises the window part 380 has heat resistance which endures the high temperature during plasma processing.

FIG. 2 is a cross-sectional view schematically showing the configuration of the window portion 380 of the present embodiment. The window portion 380 of the present embodiment includes a transparent body 381 that transmits visible light, and an ultraviolet light transmission preventing member 382 applied to the transparent body 381. As the transparent body 381, a heat-resistant fine ceramic that can be used up to 1700 ° C. was used. Specifically, the transparent body 381 is made of fine ceramics containing AlON (aluminum oxynitride). With this configuration, since the window portion 380 has sufficient heat resistance and strength, it can be used as a part of the casing of the plasma CVD apparatus 300.

The transparent body 381 is a structure of the window portion 380, and an ultraviolet transmission preventing member 382 is applied to one main surface of the transparent body 381 disposed on the outer surface side of the housing. In this embodiment, a cinnamic acid derivative such as octyl methoxycinnamate that absorbs ultraviolet light is applied as the ultraviolet light transmission preventing member 382. The transparent body 381 is formed to have a predetermined thickness or more so as not to rise to a temperature at which the applied ultraviolet light transmission preventing member 382 is chemically decomposed. The window part 380 is not limited to the transparent body 381 coated with the ultraviolet light transmission preventing member 382.

FIG. 3 is a cross-sectional view schematically showing the configuration of the window portion of the first modification of the present embodiment. As shown in FIG. 3, the window portion 480 of the first modified example of the present embodiment is formed by dispersing and containing an ultraviolet transmission preventing member 483 in a transparent body 481 that transmits visible light. Even when such a window portion 480 is formed, it is possible to form a window portion 480 that is opaque to ultraviolet rays and transparent to visible light. Alternatively, the window portion may be formed only of a transparent body made of a material that is opaque to ultraviolet rays and transparent to visible light.

FIG. 4 is a side view of the plasma CVD apparatus according to the present embodiment as seen from the back side in a state where the plasma treatment is performed. In FIG. 4, a region 400 where plasma is generated is shown with hatching.

As shown in FIG. 4, when the plasma processing is performed by the plasma CVD apparatus 300, visible light and ultraviolet rays having specific colors are generated between electrodes where plasma is generated. The color of visible light varies depending on the atoms contained in the gas species used for plasma generation.

When a thin film solar cell is manufactured on the substrate 200, various plasma generating gases are used in a thin film forming process such as when forming a semiconductor layer and when forming an electrode layer. For example, when the plasma generating gas contains SiNx, silane and ammonia, and phosphorus, visible light having different colors is generated in each case.

Since the window 380 transmits visible light, visible light generated from the plasma can be visually recognized from the outside. Therefore, when an abnormality occurs in the support state of the electrode part or the substrate, it can be easily confirmed from the outside.

On the other hand, since the window 380 does not transmit ultraviolet rays, the ultraviolet rays generated from the plasma are not emitted to the outside. Therefore, a person in the vicinity of the plasma CVD apparatus 300 can be prevented from being exposed to ultraviolet rays generated from the plasma.

As described above, when the distance between the electrodes, the degree of vacuum, and the applied voltage are constant over the entire surface of the electrodes, plasma is uniformly generated between the electrodes. In that case, visible light is generated from the whole between the electrodes. In FIG. 4, there is a region where visible light is not emitted in a part of the electrode pair. In the region where no visible light is emitted, any of the conditions such as the distance between the electrodes, the degree of vacuum, and the applied voltage does not satisfy the predetermined condition.

By providing the window portion 380 so as to be visible between the pair of electrodes, it is possible to easily confirm that some abnormality has occurred in the region where the visible light is not emitted. When an abnormality is confirmed, the processing of the substrate 200 is immediately stopped and the plasma CVD apparatus 300 is inspected.

In the conventional plasma CVD apparatus 100, even when an abnormality occurs during the processing of the substrate 200, the abnormality occurs until the opening / closing part 110 is opened and the inside of the plasma CVD apparatus 100 is confirmed after the processing of the substrate 200 is completed. It was difficult to confirm that. Since the plasma CVD apparatus 100 at the end of the substrate processing is at a high temperature of about 300 ° C., a cooling time of half a day or more is required to take out the substrate 200. For this reason, the time lag from the occurrence of abnormality of the device to the discovery is large. In addition, when a discharge detection sensor as described in the prior art is used, a complicated control device is required and the device cost is greatly increased.

By providing the window portion 380, it is possible to detect and deal with the occurrence of an abnormality of the apparatus at an early stage, thereby improving the maintainability of the plasma CVD apparatus 300 and reducing the wasteful operation time of the plasma CVD apparatus 300. can do.

In the window portion of the second modification of the present embodiment, the ultraviolet light transmission preventing member includes a photosensitive material that develops color upon receiving ultraviolet light. Specifically, the ultraviolet light transmission preventing member contains a photochromic compound.

Photochromic compounds change color when exposed to ultraviolet rays and develop color. For this reason, the window portion of the portion that has received the ultraviolet rays generated from the plasma develops color, and the other window portions do not develop color. By visually recognizing this color difference from the outside, it can be confirmed whether or not an abnormality has occurred in the plasma CVD apparatus.

When the photochromic compound stops generating ultraviolet rays from the plasma, it returns to its original molecular structure due to its own thermal motion and becomes colorless. Thus, it can be confirmed that an abnormality has occurred at that location.

In the third modification of the present embodiment, the ultraviolet light transmission preventing member includes a wavelength conversion material that emits visible light upon receiving ultraviolet light. Specifically, the ultraviolet light transmission preventing member includes a nanoparticle phosphor.

Since the nanoparticle phosphor is less likely to scatter visible light when the particle diameter is 50 nm or less, the nanoparticle phosphor is almost transparent to visible light. The nanoparticle phosphor is excited by receiving ultraviolet rays and emits visible light having a wavelength longer than that of the ultraviolet rays. Therefore, the window part of the part which received the ultraviolet-ray generated from plasma emits light, and the other window part does not light-emit. By visually recognizing the difference in light emission from the outside, it can be confirmed whether or not an abnormality has occurred in the plasma CVD apparatus.

In addition, a monitor that constantly monitors changes in the window 380 during operation of the plasma CVD apparatus is installed, and a controller that automatically stops the plasma CVD apparatus when a change in the window 380 is detected when an abnormality occurs is provided. May be. In this case, since the monitor can be disposed outside the plasma CVD apparatus, an expensive discharge detection sensor having heat resistance attached to the plasma CVD apparatus itself is not required as described in the prior art. Therefore, a normal monitor having no heat resistance can be used as the monitor, and an increase in device cost can be suppressed.

In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It does not become the basis of a limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. In addition, meanings equivalent to the claims and all modifications within the scope are included.

100, 300 plasma CVD apparatus, 110 opening / closing part, 150 lower electrode, 160 upper electrode, 200 substrate, 120, 320 main body part, 330 rear surface, 380, 480 window part, 381, 481 transparent body, 382, 483 ultraviolet light transmission preventing member , 190,390 processing chamber, 400 plasma generating area.

Claims

A plasma apparatus (300) for plasma-treating an object (200) to be processed,
A housing,
An electrode unit including a pair of electrodes (150, 160) disposed to face each other with a space between the workpiece (200) in the casing;
The housing has, on the side surface, window portions (380, 480) that can visually recognize at least the pair of electrodes (150, 160) of the electrode portions from the outside.
The said window part (380,480) is a plasma apparatus which has an impermeability with respect to the ultraviolet-ray which generate | occur | produced from plasma.
The plasma device according to claim 1, wherein the window (380) includes a transparent body (381) that transmits visible light, and an ultraviolet light transmission preventing member (382) applied to the transparent body (381).
The plasma device according to claim 1, wherein the window (480) includes a transparent body (481) that transmits visible light, and an ultraviolet light transmission preventing member (483) dispersedly contained in the transparent body (481). .
The plasma device according to claim 2 or 3, wherein the transparent body (381, 481) contains fine ceramics.
The plasma apparatus according to claim 4, wherein the transparent body (381, 481) contains AlON.
The plasma apparatus according to any one of claims 2 to 5, wherein the ultraviolet light transmission preventing member (382, 483) includes a photosensitive material that develops color upon receiving ultraviolet light.
The plasma apparatus according to claim 6, wherein the photosensitive material is a photochromic compound.
The plasma apparatus according to any one of claims 2 to 5, wherein the ultraviolet light transmission preventing member (382, 483) includes a wavelength conversion material that emits visible light upon receiving ultraviolet light.
The plasma apparatus according to claim 8, wherein the wavelength conversion material is a nanoparticle phosphor.