JP7695533B2 - Plasma Processing Equipment - Google Patents

Description

The present invention relates to a plasma processing device.

Patent Document 1 discloses a plasma processing apparatus that includes a metal plate with a slit formed therein, a dielectric plate that is supported in contact with the metal plate and closes the slit, and an antenna that is provided outside the processing chamber facing the metal plate and generates a high-frequency magnetic field. The plasma processing apparatus disclosed in Patent Document 1 can efficiently supply the high-frequency magnetic field generated by the antenna to the processing chamber.

JP 2020-198282 A

When the size of a plasma processing device is increased to expand the processing area for plasma processing, as in the plasma processing device disclosed in Patent Document 1, when a dielectric plate is supported in contact with a metal plate, there is a problem that the dielectric plate becomes difficult to handle.

One aspect of the present invention aims to make the dielectric plate easier to handle and to reduce the possibility of the dielectric plate being damaged due to thermal expansion.

In order to solve the above problems, a plasma processing apparatus according to one aspect of the present invention includes a vacuum vessel that houses an object to be processed therein, an antenna that is provided outside the vacuum vessel and generates a high-frequency magnetic field, and a magnetic field introduction window provided on a wall surface of the vacuum vessel that introduces the high-frequency magnetic field into the interior of the vacuum vessel to generate plasma inside the vacuum vessel, the magnetic field introduction window having a metal plate with multiple slits formed therein and bridging portions formed between the multiple slits, and multiple rectangular dielectric plates arranged in a line covering the multiple slits, and the multiple dielectric plates are arranged so that adjacent sides of each of the adjacent dielectric plates that face each other are located on the bridging portions.

According to one aspect of the present invention, it is possible to facilitate the handling of the dielectric plate and reduce the possibility of the dielectric plate being damaged due to thermal expansion of the dielectric plate.

1 is a cross-sectional view showing a cross-sectional configuration of a plasma processing apparatus according to a first embodiment of the present invention. FIG. 2 is a plan view of the plasma processing apparatus shown in FIG. 3 is an enlarged view of a portion surrounded by a dotted line DL shown in FIG. 2 . 4 is a cross-sectional view showing the vicinity of side 51A and the vicinity of side 52A of the dielectric plate shown in FIG. 3. FIG. 11 is a diagram showing a configuration of a plasma processing apparatus according to a second embodiment of the present invention.

[Embodiment 1]
<Configuration of Plasma Processing Apparatus 1>
Fig. 1 is a cross-sectional view showing a cross-sectional configuration of a plasma processing apparatus 1 according to a first embodiment of the present invention. In Fig. 1, the direction in which an antenna 6 extends is the X-axis direction, the direction from a vacuum vessel 2 toward the antenna 6 is the Z-axis direction, and the direction perpendicular to both the X-axis direction and the Z-axis direction is the Y-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. Fig. 2 is a plan view of the plasma processing apparatus 1 shown in Fig. 1. The antenna 6 and the high-frequency power source 7 are omitted in Fig. 2.

As shown in FIG. 1, the plasma processing apparatus 1 performs plasma processing on a workpiece W1 such as a substrate using an inductively coupled plasma P1. Here, the substrate is, for example, a substrate for a flat panel display (FPD) such as a liquid crystal display or an organic electroluminescence display, or a flexible substrate for a flexible display. The workpiece W1 may also be a semiconductor substrate used for various applications. Furthermore, the workpiece W1 is not limited to a substrate-like form, such as a tool. The processing performed on the workpiece W1 is, for example, film formation by a plasma CVD (Chemical Vapor Deposition) method or a sputtering method, plasma etching, ashing, coating film removal, etc.

The plasma processing apparatus 1 comprises a vacuum vessel 2, a magnetic field introduction window 3, an antenna 6, a high-frequency power supply 7, and a holding unit 8. Inside the vacuum vessel 2, a processing chamber 21 is formed which is evacuated and into which gas is introduced. The vacuum vessel 2 is, for example, a metal vessel. An opening 23 is formed in a wall surface 22 of the vacuum vessel 2, penetrating in the thickness direction. The vacuum vessel 2 is electrically grounded.

The gas introduced into the processing chamber 21 may be selected according to the processing contents to be performed on the workpiece W1 accommodated in the processing chamber 21. For example, when a film is formed on the workpiece W1 by plasma CVD, the gas is a raw material gas or a gas obtained by diluting the raw material gas with a dilution gas such as _H2 . More specifically, when the raw material gas is _SiH4 , a Si film can be formed on the workpiece W1; when the raw material gas is _SiH4 + _NH3 , a SiN film can be formed; when the raw material gas is _SiH4 + _O2 , a _SiO2 film can be formed; and when the raw material gas is _SiF4 + _N2 , a SiN:F film (fluorinated silicon nitride film) can be formed.

<Configuration of magnetic field introduction window 3>
The magnetic field introduction window 3 has a metal plate 4 and a plurality of dielectric plates 5. The magnetic field introduction window 3 introduces a high-frequency magnetic field generated from an antenna 6 into the processing chamber 21 in order to generate plasma in the processing chamber 21. The metal plate 4 and the dielectric plate 5 are arranged in this order along the Z-axis direction.

The metal plate 4 is provided on the wall surface 22 of the vacuum vessel 2 so as to cover the opening 23. The metal plate 4 is formed with a plurality of slits 41 penetrating the metal plate 4 in the Z-axis direction. As shown in FIG. 2, the plurality of slits 41 extend in the Y-axis direction and are aligned in the X-axis direction. The metal plate 4 is disposed so as to be substantially parallel to the surface of the workpiece W1. The metal plate 4 also has a plurality of bridging portions 42. By forming the plurality of slits 41 in the metal plate 4, the bridging portions 42 are formed between the plurality of slits 41.

The multiple dielectric plates 5 are arranged side by side on the metal plate 4 so as to cover the multiple slits 41, and each dielectric plate 5 has a rectangular shape in a plan view. The multiple dielectric plates 5 are arranged in the X-axis direction, but not in the Y-axis direction. If the multiple dielectric plates 5 were arranged in the Y-axis direction, the boundary between adjacent dielectric plates 5 in the Y-axis direction would be positioned on the slits 41, making it difficult to maintain a vacuum state in the processing chamber 21.

The width WD1 of one dielectric plate 5 along the X-axis direction is greater than the width WD2 of one slit 41 along the X-axis direction so that one dielectric plate 5 can cover one or more slits 41. The width WD1 of the dielectric plate 5 is, for example, 42.5 mm or more and 524.5 mm or less, and the width WD2 of the slit 41 is, for example, 5 mm or more and 30 mm or less.

In addition, the width WD3 of one dielectric plate 5 along the Y-axis direction is greater than the width WD4 of one slit 41 along the Y-axis direction so that one dielectric plate 5 can cover one or more slits 41. The width WD3 of the dielectric plate 5 is, for example, 40 mm or more and 70 mm or less, and the width WD4 of the slit 41 is, for example, 30 mm or more and 60 mm or less. In this case, the widths WD3 and WD4 are determined so that the width WD3 is greater than the width WD4. The width WD1 is greater than the width WD3, and the width WD2 is smaller than the width WD4.

Furthermore, when the plasma processing apparatus 1 is viewed in the negative direction of the Z axis, the area of one dielectric plate 5 is smaller than the area of the region in which the multiple slits 41 are formed. The dielectric plate 5 is provided in contact with the metal plate 4 from the outside of the vacuum vessel 2 and overlaps the metal plate 4. The dielectric plate 5 is also provided on the surface of the metal plate 4 on the antenna 6 side so as to block the multiple slits 41 from the outside of the vacuum vessel 2.

The entire dielectric plate 5 is made of a dielectric material and has a flat plate shape. The material constituting the dielectric plate 5 may be an inorganic material such as ceramics such as alumina, silicon carbide or silicon nitride, quartz glass or non-alkali glass, or a resin material such as a fluororesin such as Teflon (registered trademark).

The high-frequency magnetic field generated by the antenna 6 is supplied to the processing chamber 21 through the dielectric plate 5 and the multiple slits 41. The vacuum state of the processing chamber 21 is maintained by the metal plate 4 that covers the opening 23 and the dielectric plate 5 that covers the multiple slits 41.

<Configuration of Adjacent Dielectric Plates 5>
Fig. 3 is an enlarged view of the portion surrounded by the dotted line DL shown in Fig. 2, and Fig. 4 is a cross-sectional view showing the vicinity of sides 51A and 52A of the dielectric plate 5A shown in Fig. 3. Reference numeral 101 in Fig. 4 indicates the vicinity of side 51A, and reference numeral 102 in Fig. 4 indicates the vicinity of side 52A.

2 and 3, multiple dielectric plates 5 are arranged on the metal plate 4 so that adjacent sides of adjacent dielectric plates 5 facing each other are positioned on the bridge portion 42. The side of the dielectric plate 5 refers to the side of a rectangle for a rectangular dielectric plate 5. Consider, for example, the case where dielectric plates 5B, 5A, and 5C are arranged in this order in the X-axis direction as the dielectric plates 5, as shown in FIG. 3.

The dielectric plate 5A has four sides 51A, 52A, 53A, and 54A. Of the four sides, sides 51A and 52A are a pair of short sides of a rectangle, and of the four sides, sides 53A and 54A are a pair of long sides of a rectangle. The dielectric plate 5B has side 51B as a short side of the rectangle, and the dielectric plate 5C has side 52C as a short side of the rectangle.

Sides 51A, 51B, 52A, and 52C extend in the Y-axis direction. Sides 53A and 54A extend in the X-axis direction. As indicated by reference numeral 101 in Figs. 3 and 4, sides 51A and 51B are located on bridge portion 42 and are supported by bridge portion 42. Sides 51A and 51B are adjacent to each other and face each other, and are located near the center of the width of bridge portion 42 along the X-axis direction. Sides 51A and 51B are in contact with each other.

As shown by reference numeral 102 in Figs. 3 and 4, sides 52A and 52C of adjacent dielectric plates 5A and 5C are adjacent and face each other, are located on bridge portion 42, and are supported by bridge portion 42. A gap SP is formed between sides 52A and 52C. Not limited to dielectric plates 5A and 5C, for each dielectric plate 5, a gap SP is formed between one short side and the short side of the adjacent dielectric plate 5, and the other short side contacts the short side of an adjacent dielectric plate 5 other than the adjacent dielectric plate 5.

This prevents adjacent edges from coming into strong contact with each other even if the dielectric plate 5 expands. This prevents strong stress from being applied to the dielectric plate 5, reducing the possibility of the dielectric plate 5 being damaged.

The adjacent sides of adjacent dielectric plates 5 that face each other are the short sides of the dielectric plate 5. In this case, two of the four sides of the dielectric plate 5 that face each other are located on the bridge portion 42. For example, sides 52A and 52C of adjacent dielectric plates 5A and 5C that face each other are the short sides and are located on the bridge portion 42.

As a result, when a gap SP is formed between the opposing short sides of adjacent dielectric plates 5A, 5C, the gap SP is formed on the bridge portion 42, so that the vacuum state of the processing chamber 21 can be maintained by the dielectric plate 5. In addition, as the temperature of the dielectric plate 5 rises with the generation of plasma, the dielectric plate 5 thermally expands more in the longitudinal direction than in the transverse direction, effectively reducing the possibility of the dielectric plate 5 being damaged.

Furthermore, only one short side region of the four sides of the dielectric plate 5 is fixed to the metal plate 4 on the bridge portion 42. The short side region refers to the area of the surface of the dielectric plate 5 facing the metal plate 4 near the short side. Also, for example, only the short side region of side 51A of the four sides of the dielectric plate 5A is fixed to the bridge portion 42 with an adhesive or a jig.

When the short side region of side 51A is fixed to bridging portion 42 by adhesive, adhesive is applied between the short side region of side 51A and bridging portion 42. In addition, adhesive is applied between end face E1 of dielectric plate 5A that contacts dielectric plate 5B, and end face E2 of dielectric plate 5B that contacts dielectric plate 5A.

When the short side region of side 51A is fixed to the bridging portion 42 by a jig, the jig is fixed to the metal plate 4 so that the vicinity of sides 51A and 51B is pressed against the metal plate 4 by the jig. The short side region of side 52A is supported without being fixed to the bridging portion 42, and the long side regions of sides 53A and 54A are supported without being fixed to the metal plate 4. The long side region refers to the area near the long side of the surface of the dielectric plate 5 facing the metal plate 4. The short side region of side 51B of the dielectric plate 5B is also fixed to the bridging portion 42 by adhesive or a jig.

In this way, the areas of the dielectric plate 5 other than one short side are not fixed to the metal plate 4 but are simply supported. This reduces the stress applied to the dielectric plate 5 in the longitudinal direction when the dielectric plate 5 thermally expands, and reduces the possibility of the dielectric plate 5 being damaged.

As described above, multiple dielectric plates 5 are arranged on the metal plate 4, and the dielectric plate arranged on the metal plate 4 is divided into multiple dielectric plates 5. This allows the size of the dielectric plate 5 to be smaller than when a single dielectric plate is fixed to the metal plate 4. This reduces the possibility that the dielectric plate 5 will peel off from the metal plate 4 due to thermal expansion of the dielectric plate 5, and also reduces the possibility that the dielectric plate 5 will be damaged.

In addition, when the plasma processing apparatus 1 is enlarged to expand the processing area of the workpiece W1 to be plasma processed, the magnetic field introduction window 3 is also enlarged, and the area in which the multiple slits 41 are formed becomes larger. Therefore, when one dielectric plate 5 is fixed to the metal plate 4, the size of the dielectric plate 5 becomes large. In contrast, when multiple dielectric plates 5 are placed on the metal plate 4, the size of the dielectric plate 5 becomes smaller, and the above-mentioned possibility can be effectively reduced.

Furthermore, the cost of the dielectric plates 5 can be reduced by using multiple small dielectric plates 5 rather than using a single large dielectric plate 5. Since small dielectric plates 5 are used, it becomes easier to handle dielectric plates 5 made of easily breakable materials such as glass or ceramics.

Regarding the thermal expansion of the dielectric plate 5, consider the case where the dielectric plate 5 is made of, for example, quartz glass. The thermal expansion coefficient of quartz glass is 0.57×10 ⁻⁶ /K between 0° C. and 500° C. If the length of the dielectric plate 5 in the longitudinal direction is 1000 mm and the temperature of the dielectric plate 5 rises by 500° C., the length of the dielectric plate 5 in the longitudinal direction will expand by 0.285 mm.

It is not preferable that one of the adjacent dielectric plates 5 is fixed on one bridging portion 42 and the other dielectric plate 5 is supported without being fixed. This is because when multiple dielectric plates 5 are arranged on the metal plate 4, there is a possibility that a malfunction may occur due to misalignment of the dielectric plates 5. For this reason, as shown in FIG. 2, it is preferable that adjacent dielectric plates 5 are both fixed on one bridging portion 42, and that adjacent dielectric plates 5 are both supported without being fixed on another bridging portion 42. This improves the structural reliability of the dielectric plates 5.

The antenna 6 is linear, provided outside the vacuum vessel 2, and arranged so as to face the magnetic field introduction window 3. The length of the antenna 6 along the X-axis direction is approximately 2000 mm. The antenna 6 is arranged so as to be substantially parallel to the surface of the workpiece W1. When high-frequency power is applied from the high-frequency power source 7, the antenna 6 generates a high-frequency magnetic field. This generates an induced electric field in the space within the processing chamber 21, and an inductively coupled plasma P1 is generated in that space. The holder 8 is a stage housed within the processing chamber 21 and holds the workpiece W1.

The high-frequency magnetic field generated by the antenna 6 is supplied to the processing chamber 21 through the multiple dielectric plates 5 and the multiple slits 41. The vacuum state of the processing chamber 21 is maintained by the metal plate 4 that covers the opening 23 and the multiple dielectric plates 5 that cover the multiple slits 41.

[Embodiment 2]
A second embodiment of the present invention will be described below. For ease of explanation, the same reference numerals are used for members having the same functions as those described in the first embodiment, and the explanations thereof will not be repeated. Fig. 5 is a diagram showing the configuration of a plasma processing apparatus 1A according to the second embodiment of the present invention. In Fig. 5, the antenna 6 and the high frequency power source 7 are omitted. As shown in Fig. 5, the plasma processing apparatus 1A differs from the plasma processing apparatus 1 according to the first embodiment in that a buffer material 9 is provided.

A buffer material 9 is provided between the adjacent opposing sides of each of the adjacent dielectric plates 5, which are fixed to the metal plate 4 on a specific bridge portion 42. For example, the buffer material 9 is provided between sides 51A and 51B of the adjacent dielectric plates 5A and 5B. The buffer material 9 is, for example, a resin material such as Teflon (registered trademark).

By providing the buffer material 9 between the edges fixed to the metal plate 4 on the bridge portion 42, it is possible to prevent adjacent edges from coming into strong contact with each other even if the dielectric plate 5 expands in the longitudinal direction. This prevents strong stress from being applied to the dielectric plate 5, reducing the possibility of the dielectric plate 5 being damaged.

〔summary〕
A plasma processing apparatus according to aspect 1 of the present invention comprises a vacuum vessel for accommodating an object to be processed therein, an antenna provided outside the vacuum vessel for generating a high-frequency magnetic field, and a magnetic field introduction window provided on a wall of the vacuum vessel for introducing the high-frequency magnetic field into the interior of the vacuum vessel in order to generate plasma inside the vacuum vessel, the magnetic field introduction window having a metal plate having a plurality of slits formed therein and having bridging portions formed between the plurality of slits, and a plurality of rectangular dielectric plates arranged in a row so as to cover the plurality of slits, and the plurality of dielectric plates are arranged so that adjacent sides of adjacent dielectric plates facing each other are positioned on the bridging portions.

The plasma processing apparatus according to aspect 2 of the present invention may be configured in such a way that, in the above-mentioned aspect 1, a gap is formed between the adjacent sides that face each other.

The plasma processing apparatus according to aspect 3 of the present invention may be configured in the above aspect 1 or 2 such that the adjacent sides facing each other are each a short side of the dielectric plate.

In the plasma processing apparatus according to aspect 4 of the present invention, in the above aspect 3, the dielectric plate may be configured such that only one short side region of the four sides of the dielectric plate is fixed to the metal plate on the bridge portion.

The plasma processing apparatus according to aspect 5 of the present invention may be configured in the above-mentioned aspect 4 such that a buffer material is provided between adjacent sides of the adjacent dielectric plates that are fixed to the metal plate on the specific bridge portion so as to face each other.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in different embodiments.

Reference Signs List 1, 1A Plasma treatment apparatus 2 Vacuum vessel 3 Magnetic field introduction window 4 Metal plate 5, 5A, 5B, 5C Dielectric plate 6 Antenna 9 Cushioning material 22 Wall surface 41 Slit 42 Bridge portion P1 Plasma SP Gap W1 Treatment object

Claims (3)

a vacuum vessel for accommodating an object to be treated therein;
an antenna provided outside the vacuum vessel and configured to generate a high-frequency magnetic field;
a magnetic field introduction window provided on a wall surface of the vacuum vessel for introducing the high frequency magnetic field into the vacuum vessel in order to generate plasma inside the vacuum vessel;
The magnetic field introduction window is
A metal plate having a plurality of slits formed therein and a bridge portion formed between the plurality of slits;
a plurality of rectangular dielectric plates arranged to cover the plurality of slits;
the plurality of dielectric plates are arranged such that adjacent sides of the adjacent dielectric plates facing each other are positioned on the bridge portion ;
the adjacent sides facing each other are short sides of the dielectric plate,
The plasma processing apparatus is characterized in that the dielectric plate is fixed to the metal plate on the bridge portion only in one short side region of four sides of the dielectric plate . The plasma processing apparatus according to claim 1, characterized in that a gap is formed between the adjacent sides that face each other. 3. The plasma processing apparatus according to claim 1, wherein a buffer material is provided between adjacent edges of each of the adjacent dielectric plates, which are fixed to the metal plate on a specific bridge portion, so as to face each other.

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