JP4503574B2 - Inductively coupled plasma processing equipment - Google Patents

Description

  The present invention relates to an inductively coupled plasma processing apparatus for subjecting a substrate to be processed such as a liquid crystal display (LCD) substrate to plasma processing such as dry etching by inductively coupled plasma.

  For example, in an LCD manufacturing process, plasma processing such as etching, sputtering, and CVD (chemical vapor deposition) is frequently used for an LCD glass substrate as a substrate to be processed.

  Various plasma processing apparatuses for performing such plasma processing are used. Among them, an inductively coupled plasma (ICP) processing apparatus is known as one that can generate high-density plasma. It has been.

  In an inductively coupled plasma processing apparatus, typically, the ceiling of a processing chamber for performing plasma processing that can be maintained in a vacuum is configured by a dielectric wall, and a radio frequency (RF) antenna is disposed thereon. By supplying high-frequency power to the high-frequency antenna, an induction electric field is formed in the processing chamber, and the processing gas introduced into the processing chamber is turned into plasma by the induction electric field, and the processing gas thus formed Plasma processing such as etching is performed by plasma.

  By the way, in the LCD manufacturing process, the LCD glass substrate, which is a substrate to be processed, has such a dimension that a plurality of LCD panel products can be obtained from one. Recently, from the viewpoint of improving throughput, there is a strong demand for an LCD glass substrate having a large size with a side exceeding 1 m. Due to the increase in the size of the processing apparatus, a dielectric wall is required. Must be enlarged. When the dielectric wall becomes large in this way, it is necessary to increase its thickness in order to maintain sufficient strength to withstand the pressure difference between the inside and outside of the processing chamber and its own weight. Since the distance between the high-frequency antenna and the plasma region is increased, energy efficiency is lowered and plasma density is lowered. Further, when the thickness of the dielectric wall is increased in this way, the dielectric wall becomes extremely expensive.

As a technique for avoiding this, the main body container of the inductively coupled plasma processing apparatus is divided into an upper antenna chamber and a lower processing chamber by a partition structure, and the partition structure includes a dielectric wall. There has been proposed a technique that employs a structure in which a body wall is supported by a cross-shaped support beam and the support beam is suspended by a suspender fixed to the ceiling of the antenna chamber (Patent Document 1). Thereby, since the load concerning a dielectric wall is reduced significantly, a dielectric wall can be made thin.
JP 2001-28299 A

  However, in the technique disclosed in Patent Document 1, since the dielectric wall is supported by the support beam and the support beam is suspended by the suspender, the support beam that is a part of the partition structure is not bent. Although it is necessary to increase the width of the support beam, if the width of the support beam is increased, the effective area of the dielectric wall is reduced and the energy efficiency is lowered.

  The present invention has been made in view of such circumstances, and without increasing the support portion of the dielectric wall, and without increasing the thickness of the dielectric wall, the processing chamber and the antenna chamber including the dielectric wall are provided. An object of the present invention is to provide an inductively coupled plasma processing apparatus capable of suppressing the bending of the partition structure that partitions the spaces.

In order to solve the above-described problems, the present invention provides a processing chamber that is kept airtight and performs plasma processing on a substrate to be processed, a processing gas supply system that supplies a processing gas into the processing chamber, and an exhaust of the processing chamber. An exhaust system for depressurizing the processing chamber, a dielectric wall constituting an upper wall of the processing chamber, and an induction system provided above the dielectric wall and supplied with high-frequency power to the processing chamber a high frequency antenna to form an electric field, provided above the processing chamber, said bottom wall by a dielectric wall is formed, and an antenna chamber that houses the high-frequency antenna, so that partitions the antenna chamber into a plurality of chambers It said extending perpendicularly from the bottom wall of the antenna room to the ceiling wall, is supported on the side wall of the antenna room, comprising a vertical wall formed of aluminum or an aluminum alloy, the dielectric wall Is divided into multiples corresponding to the plurality of small chambers, the respective segments of the dielectric wall is supported by the side wall and the vertical wall of said antenna chamber, the high frequency antenna is housed respectively in said plurality of chambers An inductively coupled plasma processing apparatus including an antenna is provided.

  According to the present invention, the antenna chamber in which the bottom wall is formed by the dielectric wall is divided into a plurality of small chambers by the vertical wall supported by the side wall of the antenna chamber, and the dielectric wall is divided into a plurality corresponding to the plurality of small chambers. In addition, since each of the divided pieces of the dielectric wall is supported by the side wall of the antenna chamber and the vertical wall, and the support element is a vertical wall, the support portion of the dielectric wall is widened. Without bending the dielectric wall and without increasing the thickness of the dielectric wall, it is possible to prevent the partition structure including the dielectric wall from being bent between the processing chamber and the antenna chamber.

In the present invention, a gas flow path that guides the processing gas from the processing gas supply system into the processing chamber through a gas discharge port formed at the bottom of the vertical wall is provided inside the vertical wall. May be. In this case, the gas flow path includes a flow path formed at a portion where the two vertical walls intersect, a plurality of horizontal flow paths that are branched from the flow path and formed in a horizontal direction, and each horizontal flow path. You may make it have a some vertical flow path which further branches from the flow path, and is connected to the said several gas discharge port, respectively.
Further, high frequency power may be supplied from a single high frequency power source to the antennas accommodated in the plurality of small chambers, or high frequency power may be supplied to the antennas accommodated in the plurality of small chambers, respectively. A plurality of high frequency power supplies may be provided.

  A typical example is that the vertical wall partitions the antenna chamber into a cross and divides the antenna chamber into four small chambers.

  According to the present invention, the antenna chamber in which the bottom wall is formed by the dielectric wall is divided into a plurality of small chambers by the vertical wall supported by the side wall of the antenna chamber, and the dielectric wall is divided into a plurality corresponding to the plurality of small chambers. In addition, since each of the divided pieces of the dielectric wall is supported by the side wall of the antenna chamber and the vertical wall, and the support element is a vertical wall, the support portion of the dielectric wall is widened. Without bending the dielectric wall and without increasing the thickness of the dielectric wall, it is possible to prevent the partition structure including the dielectric wall from being bent between the processing chamber and the antenna chamber.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a vertical sectional view showing an inductively coupled plasma etching apparatus according to an embodiment of the present invention, and FIG. 2 is a horizontal sectional view showing an antenna chamber thereof. This apparatus is used for etching a metal film, an ITO film, an oxide film or the like when forming a thin film transistor on an LCD glass substrate in the manufacture of an LCD, for example.

This plasma etching apparatus has an airtight main body container 1 having a rectangular tube shape made of a conductive material, for example, aluminum or aluminum alloy whose inner wall surface is anodized. The main body container 1 is assembled so as to be disassembled, and is grounded by a ground wire 1a. The main body container 1 is divided into an antenna chamber 3 and a processing chamber 4 by a dielectric wall 2 in the vertical direction. Therefore, the dielectric wall 2 constitutes the ceiling wall of the processing chamber 4. The dielectric wall 2 is made of ceramics such as Al ₂ O ₃ , quartz, or the like.

  In the antenna chamber 3 of the main body container 1, two vertical walls 5 are provided so as to form a cross so as to be supported by two pairs of opposing side walls 3a. Therefore, the antenna chamber 3 is divided into four small chambers 6 by the two vertical walls 5. A support shelf 7 is provided at the bottom of the side wall 3 a and the vertical wall 5, and a divided piece 2 a obtained by dividing the dielectric wall 2 into four parts is placed on the support shelf 7 of each small chamber 6. A seal ring 8 is interposed between each divided piece 2 a of the dielectric wall 2 and the support shelf 7 to be hermetically sealed, and these are fixed by bolts 9. The vertical wall 5 is formed of, for example, aluminum or aluminum alloy whose surface is anodized in the same manner as the main body container 1.

  A gas inlet 11 is formed at the center of the top wall 3 b of the antenna chamber 3. And as shown in FIG. 3, the gas flow path 12 which continues to the gas inlet 11 from the upper end of the cross | intersection part 5a where the two vertical walls 5 cross | intersect is extended below. The gas flow path 12 includes a horizontal flow path 12a extending horizontally and in a cross shape along the vertical wall at the lower portion of the intersection 5a, and a plurality of vertical flow paths 12b extending downward from the cross-shaped horizontal flow path 12a. The gas discharge port 13 is formed at the bottom of the vertical wall 5. Accordingly, the plurality of gas discharge ports 13 are arranged in a cross shape, from which a predetermined processing gas is discharged in a shower shape.

  On the other hand, the gas inlet 11 is provided with a gas supply pipe 14 so as to communicate with the gas flow path 12. The gas supply pipe 14 penetrates from the ceiling of the main body container 1 to the outside thereof, and is connected to a processing gas supply system 20 including a processing gas supply source and a valve system. Therefore, in plasma etching, the processing gas supplied from the processing gas supply system 20 is supplied to the gas flow path 12 through the gas supply pipe 14, and further passes through the horizontal flow path 12a and the vertical flow path 12b to reach the vertical wall 5. Is discharged into the processing chamber 4 from a gas discharge port 13 provided at the bottom of the substrate, and is used for etching a predetermined film formed on the LCD glass substrate G disposed in the processing chamber 4.

  A high frequency antenna 15 is disposed in the antenna chamber 3. Specifically, the high-frequency antenna 15 is divided into four antenna pieces 15 a, and these antenna pieces 15 a are arranged in the small chambers 6 of the antenna chamber 3 so as to face the dielectric wall 2. . These antenna pieces 15a are formed of a planar coil antenna having a substantially square spiral shape, and antenna wires of adjacent antenna pieces are wound in opposite directions. One end of each of these antenna pieces 15 a is connected to a feeding rod 16 that extends vertically from each small chamber 6 of the antenna chamber 3, and the other end is connected to the main body container 1 and grounded via the main body container 1. .

  On the top wall 3b of the antenna chamber 3, a matching unit 17 is provided for matching the impedance of the plasma to the high-frequency transmission line impedance, and the upper ends of the power feed rods 16 are connected to the matching unit 17. On the other hand, the matching unit 17 is provided with a high frequency power source 18 for generating an induction electric field, for example, having a frequency of 13.56 MHz.

  During the plasma processing, high-frequency power for supplying an induction electric field, for example, having a frequency of 13.56 MHz, is supplied from the high-frequency power source 18 to the high-frequency antenna 15. An induction electric field is formed in the processing chamber 4 by the high-frequency antenna 15 supplied with the high-frequency power in this way, and this induction electric field causes a gas discharge port from the processing gas supply system 20 through the gas supply pipe 14 and the gas flow path 12. The processing gas discharged from 13 is turned into plasma. At this time, the output of the high frequency power source 18 is appropriately set so as to have a value sufficient to generate plasma.

  A susceptor 22 as a mounting table for mounting the LCD glass substrate G is provided below the processing chamber 4 so as to face the high-frequency antenna 15 with the dielectric wall 2 interposed therebetween. The susceptor 22 is made of a conductive material, for example, aluminum whose surface is anodized. The LCD glass substrate G placed on the susceptor 22 is attracted and held on the susceptor 22 by an electrostatic chuck (not shown).

  The susceptor 22 is housed in an insulator frame 24 and is further supported by a hollow column 25. The support column 25 penetrates the bottom of the main body container 1 while maintaining an airtight state, is supported by an elevating mechanism (not shown) disposed outside the main body container 1, and the susceptor 22 is moved by the elevating mechanism when the substrate G is loaded and unloaded. It is driven in the vertical direction. A bellows 26 that hermetically surrounds the support column 25 is disposed between the insulator frame 24 that accommodates the susceptor 22 and the bottom of the main body container 1. Airtightness in the container 4 is guaranteed. The side wall 4a of the processing chamber 4 is provided with a loading / unloading port 27 for loading and unloading the substrate G. The loading / unloading port 27 can be opened and closed by a gate valve 27a.

  A high frequency power source 29 is connected to the susceptor 22 via a matching unit 28 by a power feeding rod 25 a provided in the hollow column 25. The high frequency power supply 29 applies high frequency power for bias, for example, high frequency power having a frequency of 3.2 MHz to the susceptor 22 during plasma processing. The ions in the plasma generated in the processing chamber 4 are effectively drawn into the substrate G by the high frequency power for bias.

  Further, in order to control the temperature of the substrate G, a temperature control mechanism including a heating means such as a ceramic heater, a refrigerant flow path, and the like, and a temperature sensor are provided in the susceptor 22 (none is shown). . Piping and wiring for these mechanisms and members are all led out of the main body container 1 through the hollow support column 25.

  An exhaust mechanism 30 including a vacuum pump or the like is connected to the bottom of the processing chamber 4 via an exhaust pipe 31. The processing mechanism 4 is exhausted by the exhaust mechanism 30, and the inside of the processing chamber 4 is predetermined during plasma processing. A vacuum atmosphere (for example, 1.33 Pa) is set and maintained.

  Next, the processing operation when the plasma etching process is performed on the LCD glass substrate G using the inductively coupled plasma etching apparatus configured as described above will be described.

  First, after the gate valve 27a is opened, the substrate G is loaded into the processing chamber 4 from the loading / unloading port 27 by the transfer mechanism (not shown), placed on the placement surface of the susceptor 22, and then the electrostatic chuck ( The substrate G is fixed on the susceptor 22 by not shown). Next, the processing gas supplied from the processing gas supply system 20 into the processing chamber 4 is discharged from the gas discharge port 13 into the processing chamber 4 through the gas supply pipe 14 and the gas flow path 12 and is exhausted by the exhaust mechanism 30. By evacuating the inside of the processing chamber 4 through the pipe 31, the inside of the processing chamber 4 is maintained in a pressure atmosphere of about 1.33 Pa, for example.

  Next, a high frequency of 13.56 MHz is applied from the high frequency power source 18 to each antenna piece 15 a of the high frequency antenna 15 through the matching unit 17 and the power supply rod 16, and thereby uniform in the processing chamber 4 through the dielectric wall 2. An induced electric field is formed. Due to the induction electric field formed in this manner, the processing gas is turned into plasma in the processing chamber 4 to generate high-density inductively coupled plasma. The ions in the plasma thus generated are effectively drawn into the substrate G by the 3.2 MHz high frequency power applied from the high frequency power supply 29 to the susceptor 22, and the substrate G is uniformly etched. Is given.

  In this case, two vertical walls 5 are provided to form a cross so as to be respectively supported by two opposing side walls 3a of the antenna chamber 3 in which the bottom wall is formed by the dielectric wall 2. The wall 5 partitions the antenna chamber 3 into four chambers, the dielectric wall 2 is divided into a plurality of chambers corresponding to the plurality of chambers, and each divided piece 2 a of the dielectric wall 2 is separated from the side wall 3 a of the antenna chamber 3. Since the support element is a vertical wall so as to be supported by the vertical wall 5, the dielectric wall 2 does not have to be widened and the dielectric wall 2 is not thickened. The bending of the partition structure that partitions between the processing chamber 4 and the antenna chamber 3 can be prevented.

  The present invention can be variously modified without being limited to the above embodiment. For example, in the above-described embodiment, power is supplied to each antenna piece 15a of the high-frequency antenna 15 disposed in each small chamber 6 from one high-frequency power source through a matching unit. However, as illustrated in FIG. Independent high frequency antennas 15 ′ may be provided, and a plurality of matching units 17 ′ and high frequency power sources 18 ′ may be provided corresponding to the high frequency antennas 15 ′.

  In the above embodiment, the vertical wall is provided in a cross shape. However, as shown in FIG. 5, only one vertical wall 5 may be provided to divide the antenna chamber 3 into two parts. As shown in FIG. 4, the antenna chamber 3 may be divided by arranging a plurality of vertical walls 5 in parallel.

  Furthermore, although the case where the present invention is applied to an etching apparatus has been described in the above embodiment, the present invention is not limited to the etching apparatus, and can be applied to other plasma processing apparatuses such as sputtering and CVD film formation. Furthermore, although the LCD substrate is used as the substrate to be processed, the present invention is not limited to this, and can be applied to processing other substrates such as a semiconductor wafer.

1 is a vertical sectional view showing an inductively coupled plasma etching apparatus according to an embodiment of the present invention. The horizontal sectional view which shows the antenna chamber of the inductively coupled plasma etching apparatus of FIG. The perspective view which shows the vertical wall of the inductively coupled plasma etching apparatus of FIG. The schematic perspective view which shows the antenna part of the inductively coupled plasma etching apparatus which concerns on other embodiment of this invention. The horizontal sectional view which shows the other example of the partition state by the vertical wall of an antenna room. The horizontal sectional view which shows the further another example of the partition state by the vertical wall of an antenna room.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Main body container 2; Dielectric wall 2a; Divided piece 3; Antenna room 3a; Side wall 4; Processing room 5; Vertical wall 5a; Intersection part 6; ; Gas discharge port 14; gas supply pipe 15, 15 '; high-frequency antenna 15a; antenna piece 18; high-frequency power source 20; processing gas supply system 22; susceptor 30;

Claims (6)

A processing chamber which is kept airtight and performs plasma processing on a substrate to be processed;
A processing gas supply system for supplying a processing gas into the processing chamber;
An exhaust system for exhausting the processing chamber and depressurizing the processing chamber;
A dielectric wall constituting an upper wall of the processing chamber;
A high-frequency antenna provided above the dielectric wall and for forming an induction electric field in the processing chamber by being supplied with high-frequency power;
An antenna chamber that is provided above the processing chamber, has a bottom wall formed by the dielectric wall, and houses the high-frequency antenna;
A vertical wall formed of aluminum or an aluminum alloy that extends vertically from the bottom wall of the antenna chamber to the top wall so as to partition the antenna chamber into a plurality of small chambers, and is supported by the side wall of the antenna chamber;
The dielectric wall is divided into a plurality corresponding to the plurality of small chambers, and each divided piece of the dielectric wall is supported by a side wall of the antenna chamber and the vertical wall ,
The inductively coupled plasma processing apparatus , wherein the high-frequency antenna has an antenna housed in each of the plurality of small chambers .   A gas flow path is provided in the vertical wall to guide the processing gas from the processing gas supply system into the processing chamber through a gas discharge port formed at the bottom of the vertical wall. The inductively coupled plasma processing apparatus according to claim 1.   The gas flow path includes a flow path formed at a portion where the two vertical walls intersect, a plurality of horizontal flow paths that are branched from the flow path and formed in a horizontal direction, and a horizontal flow path. 3. The inductively coupled plasma processing apparatus according to claim 2, further comprising a plurality of vertical flow paths that branch and communicate with the plurality of gas discharge ports, respectively. 4. The inductively coupled plasma processing apparatus according to claim 1, wherein high-frequency power is supplied from one high-frequency power source to the antennas respectively accommodated in the plurality of small chambers . 4. The inductively coupled plasma processing apparatus according to claim 1, further comprising: a plurality of high-frequency power supplies that respectively supply high-frequency power to the antennas respectively accommodated in the plurality of small chambers .   The inductively coupled plasma processing apparatus according to any one of claims 1 to 5, wherein the vertical wall partitions the antenna chamber into a cross and divides the antenna chamber into four small chambers.

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