KR19980032475A - Plasma Processing Equipment - Google Patents

Abstract

The present invention relates to a plasma processing apparatus, and more particularly, to an inductively coupled plasma processing apparatus for exciting an induction plasma in a processing chamber by applying a high frequency power to a high frequency antenna.

The high frequency inductively coupled plasma etching apparatus for an LCD substrate has a processing container 102 defining an airtight processing chamber 102a, and a mounting base 106 for supporting the LCD substrate L is installed in the processing chamber 102a. In addition, a vacuum pump 136a for exhausting the inside of the processing chamber 102a and setting it to a vacuum is provided, and an antenna block 118 having a plurality of dielectric layers is provided to face the mounting table 106, and an antenna block ( In one layer 118c of 118, a high frequency antenna 120 for forming an electric field is embedded, and a power source 126 for applying a high frequency voltage is connected to the high frequency antenna 120, and the antenna block 118 is connected. Bottom layer 202 is formed as a shower head and a processing gas is supplied into the processing chamber 102a at a position between the high frequency antenna 120 and the mounting table 106, and at least a portion of the processing gas is urged to the electric field to plasma. Softens, and in the layer 202 of the showerhead The flow passage 212 is characterized in that which is set such that the projected area ratio of 15-25% in the plane outer contour of the placement surface of the mounting table 106.

Description

Plasma Processing Equipment

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus, and more particularly, to an inductively coupled plasma processing apparatus for exciting induction plasma in a processing chamber by applying high frequency power to a high frequency antenna.

In recent years, with the ultra-high integration of semiconductor devices and LCDs, there is a need for ultra-fine processing of sub-micron units and sub-half micro-units. In order to perform such a process by a plasma processing apparatus, it is important to control a high density plasma with high precision in a low pressure atmosphere (for example, 1-50 mTorr). In addition, the plasma needs to be large and uniform in order to cope with large diameter wafers and large LCD substrates.

To address this technical need, new plasma sources have to be established, and many applications are being made. For example, EP-A-0, 379, 828 discloses a high frequency inductively coupled plasma processing apparatus using high frequency antenna. As shown in FIG. 12, the high frequency induction plasma processing apparatus 10 includes one surface (ceiling surface) of the processing chamber 16 facing the mounting table 14 on which the object 12 is to be placed. 18) consists of. On the outer wall surface of the dielectric 18, a high frequency antenna 20 made of, for example, a vortex coil is provided. An electric field is formed in the processing chamber 16 by applying a high frequency power to the high frequency antenna 20 from the high frequency power supply 22 through the matching circuit 24. Plasma is generated by ionizing the gas by colliding electrons flowing in the electric field with neutral particles of the processing gas.

On the mounting table 14, a high frequency power for bias is applied from the high frequency power supply 26 to promote the incidence of plasma on the processing surface of the object to be processed 12. In addition, an exhaust port 28 communicating with an exhaust means (not shown) is provided at the bottom of the process chamber 16 so that the inside of the process chamber 16 has a predetermined pressure atmosphere. A process gas introduction port 30 for introducing a predetermined process gas into the process chamber 16 is provided at the central portion of the dielectric agent 18 forming the ceiling surface of the process chamber 16.

In the conventional high frequency inductively coupled plasma processing apparatus as described above, the dielectric provided with the high frequency antenna constitutes a ceiling of the processing chamber held in a low pressure atmosphere. Therefore, it is necessary to increase the thickness of the dielectric to counteract the pressure difference in the outside air and the processing chamber. As a result, there is a problem that the utilization efficiency of the input energy from the high frequency power supply is deteriorated. This problem is particularly noticeable in large plasma processing apparatus for processing large diameter wafers and large area LCD substrates.

In addition, unlike the gas inlet 30 of the apparatus shown in FIG. 12, a high frequency inductively coupled plasma processing apparatus that uses a shower head for supplying a processing gas into a processing chamber in combination with a high frequency antenna to cope with an increase in size of a target object has already been provided. Known. Normally, the showerhead is configured to eject the processing gas introduced from the gas inlet to the shower from the plurality of small holes through the diffusion chamber into the processing chamber. Therefore, in the high frequency inductively coupled plasma processing apparatus having the shower head, the diffusion chamber of the shower head is interposed between the high frequency antenna and the plasma generating space in the processing chamber. For this reason, a part of the high frequency energy supplied from the antenna is consumed to generate plasma in the diffusion chamber, so that the high frequency energy supplied into the processing chamber is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to increase the utilization efficiency of energy input from a high frequency power source in a high frequency inductively coupled plasma processing apparatus so that a higher density and uniform plasma can be generated even under low pressure conditions.

Another object of the present invention is to provide a high-frequency inductively coupled plasma processing apparatus having a showerhead so as to accurately control the dissociation of the processing gas by uniformly plasmalizing the processing gas.

According to a first aspect of the present invention, there is provided an apparatus for treating a substrate to be processed using plasma.

A treatment vessel defining a confidential treatment chamber,

A mounting table provided in the processing chamber and having a mounting surface for supporting the substrate to be processed;

A main exhaust machine for evacuating the processing chamber and simultaneously setting the processing chamber in a vacuum;

A high frequency antenna for forming an electric field in the processing chamber from above the placing surface;

A power supply unit for applying high frequency power to the high frequency antenna;

A main supply system for supplying a processing gas into the processing chamber, at least a portion of the processing gas is prompted by the electric field to soften the plasma, and the main supply system is located between the mounting surface and the high frequency antenna. And a shower head facing the placing surface, the shower head having a gas flow passage formed substantially parallel to the placing surface and a plurality of gas supply holes opening with respect to the placing surface;

The shower head is defined by a dielectric panel substantially consisting of a dielectric part and a hollow part including the gas flow path, and the solid part and the hollow part in a planar outer contour of the mounting surface. A2 / (A1 + A2) is set to less than 0.4 when the negative projection areas are set to A1 and A2, respectively.

According to a second aspect of the present invention, in the apparatus for processing a substrate using a plasma,

A treatment vessel defining a confidential treatment chamber,

A mounting table provided in the processing chamber and having a mounting surface for supporting the substrate to be processed;

A main exhaust machine for evacuating the processing chamber and simultaneously setting the processing chamber to a vacuum;

An antenna block facing the placing surface and installed to contact the inner surface of the processing chamber;

A high frequency antenna installed in the antenna block for forming an electric field in the processing chamber above the mounting surface;

A power supply unit for applying high frequency power to the high frequency antenna;

A main supply system for supplying a processing gas into the processing chamber, at least a portion of the processing gas is prompted by the electric field to soften the plasma, and the main supply system is located between the mounting surface and the high frequency antenna. And a shower head defined by an opposing wall made of a dielectric material of the antenna block facing the placing surface, wherein the shower head has a gas flow passage formed substantially parallel to the placing surface, It is provided with the some gas supply hole opening with respect to it.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the etching apparatus for LCD board | substrates which is application of the plasma processing apparatus concerning embodiment of this invention.

FIG. 2 is a schematic plan view showing a high frequency antenna embedded in a dielectric of the etching apparatus shown in FIG.

3 is a plan view showing a process gas supply layer of the etching apparatus shown in FIG.

4 is a plan view showing a modification of the processing gas supply layer of the etching apparatus shown in FIG.

5 is a cross-sectional view showing an etching apparatus for an LCD substrate which is an application of a plasma processing apparatus according to another embodiment of the present invention.

6 is a schematic plan view showing a high frequency antenna of the etching apparatus shown in FIG.

Fig. 7 is a sectional view showing an etching apparatus for an LCD substrate which is an application of a plasma processing apparatus according to still another embodiment of the present invention.

8 is a plan view showing a relationship between a high frequency antenna and a processing gas flow path of the etching apparatus shown in FIG.

9 is a cross-sectional view showing a relationship between a high frequency antenna and a processing gas flow path of the etching apparatus shown in FIG.

FIG. 10 is a plan view showing a modification of the process gas supply layer of the etching apparatus shown in FIG.

FIG. 11 is a schematic diagram showing the intensity distribution of electric field energy by a high frequency antenna of the etching apparatus shown in FIG.

12 is a schematic cross-sectional view showing a conventional high frequency inductively coupled plasma processing apparatus.

※ Explanation of symbols for main parts of drawing

10: plasma processing apparatus 12: target object

14, 106: Base 16: Processing Room

18: dielectric 20, 120, 162: high frequency antenna

22, 126: high frequency power supply 30: process gas inlet

100: plasma etching apparatus 102: processing container

108: bellows 114: cooling jacket

115: gas supply pipe 116: clamp frame

118: antenna block 124: matching circuit

128, 212: gas flow path 130: source of treated gas

134: process gas supply pipe 138: gate valve

160: antenna chamber 172: processing gas supply hole

190: controller 216, 226: manifold

218, 228: Branch 224: Innet

1 shows an etching apparatus for an LCD substrate which is an application of a plasma processing apparatus according to an embodiment of the present invention.

The plasma etching apparatus 100 shown in FIG. 1 has a processing container 102 molded into a cylindrical or rectangular angular cylinder made of a conductive material, for example, aluminum or stainless steel, which has been subjected to anodizing on its surface. The predetermined etching treatment is performed in the processing chamber 102a formed in the processing container 102.

The processing vessel 102 is grounded through line 102c. At the bottom of the processing container 102, a substantially rectangular mounting table 106 for mounting a target object, for example, an LCD substrate L, is provided. The mounting base 106 is made of, for example, an electrode portion 106a made of a conductive material such as aluminum or stainless steel, which has been subjected to anodizing on its surface, and ceramics for covering portions other than the mounting surface of the electrode portion 106a. It consists of the electrode protection part 106b which consists of an insulating material. The mounting base 106 is attached to the lifting shaft 106c drilled into the bottom of the processing container 102. The lifting shaft 106a is free to move up and down by a lifting mechanism (not shown), and can raise and lower the whole mounting base 106 as needed. Moreover, the bellows 108 which is free of shrinkage for keeping the inside of the process chamber 102a airtight is provided in the outer peripheral part of the lifting shaft 106a.

The high frequency power supply 112 is electrically connected to the electrode portion 106a of the mounting table 106 through the matching circuit 110. At the time of plasma treatment, a predetermined high frequency, for example, 2 MHz high frequency power is applied to the electrode portion 106a to generate a bias potential and effectively attract the plasma excited in the processing chamber 102a to the processing surface of the substrate L. have. In addition, although the structure shown in FIG. 1 showed the structure which applies the high frequency power for bias to the mounting base 106, the structure which grounds the mounting base 106 can also be employ | adopted.

The cooling jacket 114 is built in the electrode part 106a of the mounting base 106. In the cooling jacket 114, for example, a refrigerant such as ethylene glycol, which has been warmed by a tiller, is introduced through the refrigerant introduction pipe 114a. The introduced ethylene glycol circulates in the cooling jacket 114 to generate cold heat. With this configuration, cold heat of ethylene glycol can be transferred from the cooling jacket 114 to the substrate L via the mounting table 106, and the temperature of the processing surface of the substrate L can be warmed to a desired temperature. Done. Ethylene glycol circulated through the cooling jacket 114 is discharged out of the container from the refrigerant discharge pipe 114b. Although omitted in the apparatus shown in FIG. 1, a heating means such as a heating heater may be provided on the mounting table 106 so that the surface of the substrate L may be heated.

On the mounting surface of the mounting table 106, a plurality of holes 115a are drilled and installed. The heat transfer efficiency can be increased by supplying a predetermined heat transfer gas, for example, helium gas, from the gas supply pipe 115 through the hole 115a between the mounting surface of the mounting table 106 and the inner surface of the substrate L. . This makes it possible to efficiently heat the substrate L even under a reduced pressure atmosphere.

In addition, a clamp frame 116 capable of clamping the outer frame portion of the substrate L is provided on the mounting table 106. The clamp frame 116 is supported by, for example, four support pillars 116a which are mounted upright around the mounting table 106. The substrate L can be remounted on the mounting table 106 by raising the mounting table 106 on which the substrate L is placed and bringing the clamp frame 116 into the outer frame portion of the substrate L. The pusher pin (not shown) is also provided in the mounting base 106, and the board | substrate L can be mounted on the mounting base 106 or lifted from the mounting base 106 by elevating this pusher pin.

In addition, an antenna block 118 in which the high frequency antenna 120 is embedded is provided so as to contact the ceiling plate portion 102b of the processing container 102 that substantially faces the mounting surface of the substrate L of the mounting table 106. The antenna block 118 has a laminated structure, and in the illustrated example, each has a four-layer structure made of a dielectric material. That is, the antenna buried layer 118c in which the high frequency antenna 120 is embedded in the compressed powdery dielectric material such as the Pyrex layer 118a, the quartz layer 118b, and the mica on the ceiling plate part 102b side is processed in the quartz. The gas path is constituted by the process gas supply layer 118b.

As the dielectric material to be laminated, when the high frequency antenna 120 is heated by application of high frequency power, it is preferable to use a material having an approximate thermal expansion coefficient so that a phenomenon such as peeling does not occur due to the heat. In the illustrated example, mica and pyrex are used in consideration of workability and cost, but the whole may be made of quartz. The number of layers to be laminated is not limited to four layers, and more dielectric layers may be stacked. Alternatively, a high frequency antenna may be embedded in the antenna block formed of a single dielectric layer without having a stacked structure.

The ceiling plate part 102b of the processing container 102 is free to be removed together with the antenna block 118 and the high frequency antenna 120. Accordingly, it is possible to easily manage the antenna block 118 and the high frequency antenna 120.

As shown in FIG. 2, the antenna buried layer 118c has a structure in which a band-shaped conductor, such as a copper plate, an aluminum plate, a stainless plate, or the like is sandwiched in a dielectric layer of a compressed powdery mica or the like as the high frequency antenna 120. As shown in FIG. Have By embedding the high frequency antenna 120 in the powdery dielectric material, the antenna buried layer 118c can absorb thermal expansion of the antenna 120, thereby preventing occurrence of peeling or the like.

When the high frequency antenna 120 is embedded in a general solid dielectric material such as quartz, when the high frequency power is applied to the high frequency antenna 120 and the high frequency antenna 120 and its surroundings are heated, the dielectric layer and the high frequency antenna 120 are thermally expanded. Due to the difference in the rates, deformation may occur due to thermal expansion of the high frequency antenna 120, and there is a concern that a phenomenon such as peeling may occur. Therefore, in such a case, as shown in FIG. 2, it is preferable to install cutouts 120a in various places of the high frequency antenna 120 to absorb the thermal expansion of the high frequency antenna 120.

In other words, if the incision 120a is provided on the high frequency antenna 120 at the same time as using the powdery dielectric material, the thermal expansion component of the high frequency antenna 120 is absorbed synergistically, so that deformation is less likely to occur, which is undesirable. It can prevent the occurrence of a phenomenon.

In the illustrated example, the high frequency antenna 120 is composed of several turns of vortex coils, and the high frequency antenna 120 may have a function indicating an antenna action for generating plasma, and may be a turn if the frequency is high.

Referring again to FIG. 1, a feed path 122a and a ground path 122b are provided to penetrate the Pyrex layer 118a and the quartz layer 118b, and to the high frequency antenna 120 in the mica layer 118c. . The high frequency power supply 126 is connected to the feed path 122a through the matching circuit 124. At the time of processing, a high frequency power of a predetermined frequency, for example, 13.56 MHz, may be applied to the high frequency antenna 120 from the high frequency power supply 126 to excite the induced plasma in the processing chamber 102a. In addition, the dielectric existing between the high frequency antenna 120 and the ceiling plate portion 102b of the grounded processing container 102 serves to prevent the capacitance component of the high frequency antenna 120 from increasing due to the influence of the grand. .

The process gas supply layer 118d is formed by forming a gas flow path 128 in a panel made of a dielectric material such as quartz. As shown in FIG. 3, a plurality of holes 128a communicating with the gas flow path 128 are formed in the surface of the processing gas supply layer 118d on the mounting base 106, and a shower head is formed. Predetermined process gas supplied to the gas flow path 128 from the process gas source 130 through the flow control device (MFC) 132, for example, CF ₄ gas (for SiO ₂ etching), BCl ₃ + Cl ₂ gas (For Al etching) is blown into the processing chamber 102a from the hole 128a onto the shower. As a result, the concentration of the processing gas in the processing chamber 102a is made uniform, and thus plasma of uniform density can be excited in the processing chamber 102a.

In addition, in the example shown in FIG. 3, the process gas supply layer 118d is part of the layer structure. Instead, as shown in FIG. 4, the process gas supply pipe 134 made of a dielectric material such as quartz is embedded in the antenna buried layer 118c. Can be installed on the mounting table 106 side. In this case, a plurality of holes 134a are drilled and installed in the mounting base 106 side of the processing gas supply pipe 134, and the processing gas is blown into the processing chamber 102a from the holes 134a.

The coolant may be circulated by installing a path through which coolant circulates in the antenna block 118. Accordingly, it is possible to cool the heated high frequency antenna 120 by applying high frequency power and to extend the lifespan of the high frequency antenna 120 and the antenna block 118.

The antenna block 118 and the high frequency antenna 120 of the etching apparatus 100 according to the present embodiment are integrally provided inside the processing container 102. Therefore, despite the atmospheric pressure and the pressure difference in the processing chamber, the thickness of the dielectric layer on the side of the target object can be made thinner than that of the high frequency antenna 120. Therefore, by the high frequency power applied from the high frequency power supply 126 to the high frequency antenna 120, a stronger electric field can be formed in the processing chamber 102a, and effective use of the high frequency energy can be achieved. In addition, since the thickness of the dielectric can be freely adjusted, it becomes possible to control the distribution and density of the induced plasma excited in the processing chamber with higher precision.

The exhaust pipe 136 connected to the exhaust means, for example the vacuum pump 136a, is connected to the bottom of the processing container 102. By discharging the atmosphere in the processing chamber 102a by the exhaust means, the atmosphere in the processing chamber 102a can be vacuumed to an arbitrary degree of reduced pressure.

The gate valve 138 is installed on the side of the processing container 102. The unprocessed LCD substrate L is brought into the processing chamber 102a from a load lock chamber (not shown) adjacent to the gate valve 138 by a conveying mechanism (not shown) such as a transfer arm. The substrate L can be carried out.

Next, the operation of the plasma etching apparatus shown in FIG. 1 will be described.

First, the substrate L is accommodated in the processing chamber 102a by a transfer arm (not shown) via the gate valve 138. At this time, the mounting table 106 is in the lower position and the pusher pin (not shown) is raised. The transfer arm evacuates the processing container 102 through the gate valve 138 with the substrate L on the pusher pin. Next, the pusher pin is lowered and the substrate L is placed on the mounting surface of the mounting table 106. Next, the mounting base 106 is raised by driving of the lifting mechanism, and the peripheral frame of the substrate L is pressed on the lower surface of the clamp frame 116 to fix the substrate L to the mounting base 106.

The processing chamber 102a is vacuumed by a vacuum pump 136a connected to the exhaust pipe 136. In addition, a predetermined process gas, for example, CF ₄ gas (for SiO ₂ etching), BCl ₃ + Cl ₂ gas (for Al etching), is processed from the process gas supply hole 128a of the process gas supply layer 118d. Is introduced. As a result, the process chamber 102a is maintained at a low pressure of about 30 mTorr, for example. High frequency power of, for example, 13.56 MHz is applied from the high frequency power supply 126 to the high frequency antenna 120 embedded in the antenna buried layer 118c of the antenna block 118. Then, an electric field is formed in the processing chamber 102a by the induction of the inductance component of the high frequency antenna 120. The high frequency antenna 120 is embedded in the antenna buried layer 118c of the antenna block 118 provided in contact with the ceiling 102b of the processing container 102. For this reason, the thickness of the dielectric layer on the opposite surface side to the object to be processed can be made thinner than that of the conventional one. Therefore, a stronger electric field is formed in the processing chamber 102a than in the conventional apparatus, and as a result, a higher density plasma can be generated in the processing chamber 102a.

The plasma excited in the processing chamber 102a moves in the direction of the substrate L on the mounting table 106 by the bias potential applied to the mounting table 106. In this way, a desired etching process can be performed on the processing surface using plasma. After the predetermined etching process is completed, the completed LCD substrate L is carried out to the load lock chamber through the gate valve 138 by the transfer arm, and the series of operations is completed.

According to the plasma processing apparatus which concerns on embodiment described with reference to FIGS. 1-4 which illustrate the etching apparatus, the outstanding effect as shown below can be achieved.

Since the dielectric in which the high frequency antenna is embedded is provided in contact with the processing container, the dielectric thickness can be made thin in spite of the atmospheric pressure and the pressure difference in the processing chamber. Therefore, it is possible to effectively use the high frequency energy applied to the high frequency antenna. In addition, since the thickness of the dielectric can be freely adjusted, it becomes possible to control the distribution and density of the induced plasma excited in the processing chamber with higher precision.

In addition, the processing gas is uniformly supplied into the processing chamber from a plurality of gas blowing holes provided in the side of the surface of the dielectric disposed in the plasma processing apparatus opposite to the target object. Therefore, even in the case of treating a large diameter wafer or a large area LCD substrate, the treatment can be performed by plasma excited at a uniform density in the processing chamber, thereby improving the in-plane uniformity of the treatment.

In addition, since the antenna block provided in the plasma processing apparatus is constituted by stacking a plurality of dielectric members, a structure in which a high frequency antenna or a processing gas supply path is built can be manufactured relatively easily. In addition, the antenna block formed in the laminated structure is robust and the member can be easily replaced.

Fig. 5 shows an etching apparatus for an LCD substrate which is an application of a plasma processing apparatus according to another embodiment of the present invention. In Fig. 5, parts common to those of the etching apparatus shown in Fig. 1 are denoted by the same reference numerals and detailed description thereof will be made only when necessary.

In the etching apparatus shown in FIG. 5, the antenna block, ie, the antenna chamber 160, which is hollow so as to be in contact with the ceiling plate portion 102b of the processing container 102 that substantially faces the mounting surface of the substrate L of the mounting table 106. ) Is installed. The antenna chamber 160 is defined by an airtight container made of, for example, a dielectric such as quartz glass or ceramic. In the antenna chamber 160, as shown in FIG. 6, a high frequency antenna 162 is formed in which a conductor, for example, copper, aluminum, stainless, or the like is formed in a vortex, a coil, or a loop. The high frequency antenna 162 shown in FIG. 6 is composed of two turns of vortex coils. The antenna 162 may have a function indicating an antenna action for generating plasma, and may be one turn if the frequency is high. The high frequency power supply 126 for plasma generation is connected between the both terminals of the high frequency antenna 162, that is, the terminals 162a and 162b through the matching circuit 124.

The antenna chamber 160 is configured such that the thickness of the wall 160a on the side facing the substrate L becomes thinner than the thickness of the wall 160b on the side contacting the ceiling portion 102b of the processing container 102 grounded. Thereby, the electric field by the high frequency energy applied to the high frequency antenna 162 from the high frequency power supply 126 can be concentrated on the board | substrate L side. For this reason, compared with the conventional apparatus, it becomes possible to produce a higher density plasma in the process chamber 102a.

The air supply pipe 166 is connected to the antenna chamber 160, and the antenna chamber gas for cooling and pressure adjustment, for example, an inert gas, is introduced into the antenna chamber 160. In addition, an exhaust pipe 167 connected to the vacuum pump 167a is connected to the antenna chamber 160. It is possible to extend the life of the high frequency antenna 162 by cooling the high frequency antenna 162 which is overheated when the high frequency energy is applied from the high frequency power supply 126 by the antenna chamber gas, that is, the inert gas.

As shown in FIG. 5, a coolant flow path 163 through which a coolant, for example, cold water, flows is formed in the wall of the antenna chamber 160. Cold water flows into the refrigerant passage 163 to prevent overheating of the antenna chamber 160 and to extend the life of the high frequency antenna 162.

According to the above configuration, the inside of the antenna chamber 160 can be adjusted to less than atmospheric pressure, preferably 100 Torr or more, by adjusting the flow rate of the gas introduced from the air supply pipe 166 to the antenna chamber 160 and the exhaust amount of the exhaust pipe 167. . On the other hand, in the conventional apparatus, since the high frequency antenna is placed in an atmospheric pressure atmosphere, it is necessary to increase the thickness of the dielectric across the atmosphere and the processing chamber so as to cope with the pressure difference between the atmospheric pressure and the processing chamber pressure, for example, several 10 mTorr. .

That is, according to the apparatus shown in FIG. 5, since the pressure in the antenna chamber 160 is adjusted to less than atmospheric pressure, the pressure difference between the antenna chamber 160 in which the high frequency antenna 162 is installed and the processing chamber 102a can be reduced. Therefore, the thickness of the wall 160a across the antenna chamber 160 and the processing chamber 102a can be made thinner. As a result, the electric field by the high frequency energy applied from the high frequency power supply 126 to the high frequency antenna 162 can be more concentrated in the processing chamber 102a than in the conventional apparatus, and a high density plasma can be obtained.

If necessary, as shown in FIG. 5, the vacuum pump 136a connected to the bottom of the processing chamber 102a and the vacuum pump 167a of the antenna chamber 160 are connected to the pressure controller 190 and the controller 190 is connected. By this, the displacement of the vacuum pump 167a can be controlled so that the pressure difference between the processing chamber 102a and the antenna chamber 160 is within a predetermined range. In this way, the thickness of the wall 160a across the antenna chamber 160 and the processing chamber 102a can be made thinner.

The process gas supply unit 168 is disposed on the lower surface of the antenna chamber 160. The process gas supply unit 168 is formed by forming a gas flow passage 172 in a panel made of a dielectric material such as quartz. On the surface of the mounting base 106 side of the processing gas supply unit 168, a plurality of holes 172a communicating with the gas flow passage 172 are drilled in the same shape as the holes 128a shown in FIG. Is composed. Therefore, a predetermined process gas supplied to the gas flow passage 172 from the process gas source 130 through the flow control device (MFC) 132, for example, CF ₄ gas (for etching SiO ₂ ), BCl ₃ + Cl ₂ (For Al etching) is blown into the processing chamber 102a from the hole 172a onto the shower. As a result, the concentration of the processing gas in the processing chamber 102a is made uniform, and thus plasma of uniform density can be excited in the processing chamber 102a.

Next, the operation of the plasma etching apparatus shown in FIG. 5 will be described.

First, when the board | substrate L is fixed to the mounting base 106 in the same procedure as the operation of the apparatus shown in FIG. 1, it is vacuum-pulled by the vacuum pump 136a connected to the exhaust pipe 136 in the process chamber 102a. At the same time, predetermined process gases, such as CF ₄ gas (for SiO ₂ etching) and BCl ₃ + Cl ₂ (for Al etching), are supplied from the process gas supply hole 172a of the process gas supply unit 168 into the process chamber 102a. Is introduced. As a result, the process chamber 102a is maintained at a low pressure of about 30 mTorr, for example. In the antenna chamber 160, the antenna chamber gas, that is, the inert gas, is supplied from the air supply pipe 166 and maintained at a pressure of less than atmospheric pressure, for example, about 100 Torr.

High frequency energy of, for example, 13.56 MHz is applied from the high frequency power supply 126 to the high frequency antenna 162 in the antenna chamber 160 through the matching circuit 124. Then, a power source is formed in the processing chamber 102a by the induction action of the inductance component of the high frequency antenna 162. The antenna chamber 160 is installed in contact with the ceiling portion 102b of the installed processing vessel 102, and at the same time, the thickness of the wall 160a on the side opposite to the object to be processed in the antenna chamber 160 is thinner than that of the conventional apparatus. do. Therefore, a stronger electric field is formed in the processing chamber 102a than in the conventional apparatus, and as a result, a higher density plasma can be generated in the processing chamber 102a.

Thus, the desired etching process is performed with respect to a process surface using the plasma produced | generated in the process chamber 102a. The substrate L after the etching process is carried out to the load lock chamber in the same order as the operation of the apparatus shown in FIG. 1 and the series of operations is completed.

According to the plasma processing apparatus according to the embodiment described with reference to Figs. 5 and 6 illustrating the etching apparatus, it is possible to achieve excellent effect as shown below.

Since the hollow antenna lock, that is, the antenna chamber, which is maintained at a pressure atmosphere of less than atmospheric pressure, is installed in the processing chamber, the thickness of the sidewall of the antenna chamber is thinner compared to the thickness of the conventional dielectric that has isolated the atmospheric and low pressure processing chambers. can do. Therefore, the high frequency energy applied from the high frequency power source can be more efficiently propagated in the processing chamber. In addition, since the side wall of the antenna chamber is in contact with the side surface of the grounded processing chamber, an electric field due to high frequency can be concentrated on the opposite surface (that is, the surface opposite to the processing target object), whereby a higher density plasma can be generated.

Moreover, it is possible to cool the high frequency antenna heated by applying high frequency energy from the high frequency power supply with the antenna chamber gas. In addition, by adjusting the air supply amount and the exhaust amount of the antenna chamber gas, the pressure in the antenna chamber can be controlled to a desired pressure less than atmospheric pressure.

In addition, since the thickness of the side wall on the side of the antenna chamber that faces the object to be processed is thinner than the thickness of the side wall on the wall surface of the processing chamber, a high-density electric field at high frequency is formed in the direction of the object. Therefore, high-density plasma can be generated in the processing chamber by increasing the use efficiency of high frequency energy.

Further, by providing the processing gas supply means on the wall on the side of the antenna chamber facing the object to be processed, the processing gas can be supplied into the processing chamber from, for example, a plurality of processing gas supply holes formed on the side of the object facing surface. Thereby, the distribution density of a process gas can be made uniform, and the plasma density produced in a process chamber can be made uniform.

In addition, a coolant channel through which a coolant flows is provided on a wall on the side of the antenna chamber facing the object to be processed, and the inside of the heated antenna chamber can be cooled by flowing cold water through the coolant channel, for example.

Fig. 7 shows an etching apparatus for an LCD substrate which is an application of the plasma processing apparatus according to another embodiment of the present invention. This embodiment is different from the process gas supply layer 218d shown in FIG. 1 in that the process gas supply layer 210 for defining the showerhead that is the lowermost layer of the antenna block 118 is described later. And the same as the embodiment shown in FIG. Therefore, parts common to those of the etching apparatus shown in FIG. 1 are denoted by the same reference numerals and detailed description thereof will be made only when necessary.

The process gas supply layer 210 is made of a panel made of a dielectric material, such as quartz, similarly to the process gas supply layer 118d. Grooves for forming a gas flow path are formed in the surface of the processing gas supply layer 210 facing the antenna buried layer 118c. The layers 118c and 210 are joined to form a gas flow path 212 extending in parallel with the mounting surface of the mounting table 106 by the groove of the processing gas supply layer 210. A plurality of holes 212a are formed in the process gas supply layer 210 so as to open from the gas flow passage 212 with respect to the mounting surface of the mounting table 106. Therefore, predetermined process gas supplied to the gas flow path 212, for example, CF ₄ gas (for SiO ₂ etching), BCl ₃ + Cl ₂ gas (for Al etching), is showered from the hole 2122a into the process chamber 102a. Blown in). As a result, the concentration of the processing gas in the processing chamber 102a is made uniform, and thus plasma of uniform density can be excited in the processing chamber 102a.

More specifically, as shown in FIG. 8, the gas flow passage 212 has a symmetrical shape in the up, down, left, and right directions (in FIG. 8). The gas flow path 212 includes a pair of inlets 214 connected to the process gas source 130 through a flow control device (MFC) 132 and a pair of manifolds 216 connected to the inlet 214 at a right angle. ) And a plurality of branches 218 connecting the manifold 216 to traverse the process gas supply layer 210. The branch 218 has the same cross-sectional area, for example, which is substantially rectangular in cross section, and the gas supply holes 212a are equally distributedly connected.

Since the showerhead is defined by a process gas supply layer 210 made of a panel made of a dielectric, in other words, it consists of a combination of a hollow portion including a dielectric solid portion and a gas flow passage 212. Here, when the projection areas of the solid part and the hollow part in the plane outer contour of the mounting surface of the mounting table 106 are A1 and A2, respectively, A2 / (A1 + A2) is less than 0.4, preferably from 0.1 to 15 0. It is set to 25. The range of this projected area ratio is selected in consideration of the influence of the high frequency induction electric field by the gas flow path 212 and the high frequency antenna 120 and mutual effects.

In the flow path 212 interposed between the high frequency antenna 120 and the processing chamber 102a, the processing gas easily discharges due to the influence of an electric field and is easily plasmalized. By generating this plasma, the electric field energy to be supplied from the high frequency antenna 120 to the processing chamber 102a is reduced, that is, the electric field energy is lost due to the presence of the gas flow path 212.

However, in the present invention, the hollow portion of the processing gas supply layer 210 has a projected area ratio in the out-of-plane contour of the mounting surface of the mounting table 106, as described above, preferably 15% to 25%. It is set to be. For this reason, as shown in FIG. 9, the solid dielectric portion of the processing gas supply layer 210 mainly exists between the high frequency antenna 120 and the processing chamber 102a. Therefore, the use efficiency of energy input through the high frequency antenna 120 from the high frequency power source can be improved. In addition, although the loss of the electric field energy due to the presence of the gas flow path 212 cannot be completely eliminated, sufficient electric field energy from the portion of the process gas supply layer 210 in which the gas flow path 212 does not exist in the process chamber 102a. Is supplied.

In addition, in the plane layout of the mounting surface of the mounting table 106, the gas flow path 212 and the high frequency antenna 120 are substantially linearly symmetrical with respect to the center of the mounting surface of the mounting table 206. Or point symmetrical. That is, due to the energy loss due to plasma formation of the processing gas in the gas flow passage 212, the gas flow passage 212 is supplied from the high frequency antenna 120 into the processing chamber 102a in the portion where the gas flow passage 212 is not present. The electric field energy is different. This causes the uniformity of the high frequency induction field formed in the processing chamber 102a by the high frequency antenna 120. Therefore, not only the projection area of the gas flow path 212 is reduced, but also the shape of the gas flow path 212 and the high frequency antenna 120 is centered on the substrate L on the mounting table 106 (and thus the center of the mounting surface). Substantially line symmetry or point symmetry with respect to) contributes to the uniformity of the plasma treatment.

The electric field energy supplied from the antenna 120 forms an intensity distribution as shown in FIG. As shown in FIGS. 8 and 11, the antenna 120 has an inner circumferential portion 120C and an outer circumferential portion 120S spaced apart from each other, and an intermediate portion 120M in which a coil portion is hardly present is formed therebetween. However, the electric field energy generated by the cooperation of the inner circumferential portion 120C and the outer circumferential portion 120S is the strongest in the intermediate portion 120M as shown in FIG. Therefore, if the gas flow path 212 is installed directly below the middle portion 120M, the electric field energy of the middle portion 120M passing therethrough may be reduced. As a result, the intensity of the electric field in the processing chamber 102a can be made uniform, and therefore, the processing gas can be made uniform.

FIG. 10 is a plan view showing a modification of the processing gas supply layer of the etching apparatus shown in FIG. 7.

In this modification, the process gas supply layer 220 is made of a panel made of a dielectric such as quartz, similarly to the process gas supply layer 118d. In the processing gas supply layer 220, a gas flow path 222 extending in parallel with the mounting surface of the mounting table 106 is formed. A plurality of holes 222a are formed in the process gas supply layer 220 so as to open from the gas flow path 222 to the mounting surface of the mounting table 106.

More specifically, the gas flow passage 222 has a shape that is point symmetrical with respect to the center of the placing surface of the placing table 106. The gas flow path 222 includes a pair of inlets 224 connected to the process gas source 130 through a flow control device (MFC) 132, and a pair of manifolds 226 connected to the inlet 224 at a right angle. ) And a plurality of branches 228 branching from the ends of the manifold 226. Inlet 224, manifold 226 and branch 228 have the same cross-sectional area, for example approximately rectangular in cross section. One gas supply hole 222a is provided only at one end of each branch 228. Each length from the inlet 224 of the gas flow path 222 to the gas supply hole 222a is set to be the same, so that each conductance from the inlet 224 to the gas supply hole 222a is the same. do. As a result, the processing gas can be uniformly branched into the processing chamber 102a.

In addition, the characteristics of the projected area and arrangement of the gas flow path 212 and the conductance of the gas flow path are characterized in that the high frequency antenna 120 is installed in the hollow antenna block as shown in FIG. 5, that is, the antenna chamber 160. The present invention can also be applied to an apparatus or an apparatus installed outside the processing vessel.

According to the plasma processing apparatus according to the embodiment described with reference to FIGS. 7 to 10 illustrating the etching apparatus, excellent effect as shown below can be achieved.

In the planar layout of the mounting surface of the mounting table, the gas flow path of the shower head can specify the ratio or the overlapping area of the high frequency antenna to suppress the adverse effects between the high frequency induction field and the high frequency induction field caused by the gas flow path and the high frequency antenna. have. Therefore, it is possible to control the progress of dissociation of the processing gas while simultaneously plasmaming the processing gas.

Further, by making the same conductance from the inlet of the gas flow path to the gas supply hole, the processing gas can be uniformly dispersed in the processing chamber.

In each of the above embodiments, the case where the LCD substrate is treated as the object to be processed has been described as an example. However, the present invention can also be applied to a processing apparatus having a semiconductor wafer as the object to be processed. Moreover, although each said embodiment showed the example which applied this invention to the etching apparatus, this invention is applicable also to the various apparatus using plasma, for example, an earthing apparatus and a plasma CVD apparatus.

Claims (22)

In the apparatus for performing the treatment using a plasma to the substrate to be processed, A treatment vessel defining a confidential treatment chamber, A mounting table provided in the processing chamber and having a mounting surface for supporting the substrate to be processed; A main exhaust machine for evacuating the processing chamber and simultaneously setting the processing chamber in a vacuum; A high frequency antenna for forming an electric field in the processing chamber from above the placing surface; A power supply unit for applying high frequency power to the high frequency antenna; A main supply system for supplying a processing gas into the processing chamber, at least a portion of the processing gas is prompted by the electric field to soften the plasma, and the main supply system is located between the mounting surface and the high frequency antenna. And a shower head facing the placing surface, the shower head having a gas flow passage formed substantially parallel to the placing surface and a plurality of gas supply holes opening with respect to the placing surface; The shower head is defined by a dielectric panel substantially composed of a dielectric part and a hollow part including the gas flow path, and respectively defines a projection area of the solid part and the hollow part in a planar outer contour of the mounting surface. When A1 and A2 are set, A2 / (A1 + A2) is set to less than 0.4, The plasma processing apparatus characterized by the above-mentioned. The method of claim 1, Said A2 / (A1 + A2) is 0.15-0. Plasma processing apparatus, characterized in that set to 25. The method of claim 1, And said gas flow path and said high frequency antenna are arranged to be substantially line-symmetrical or point-symmetrical with respect to the center of said mounting surface in the planar layout with respect to said mounting surface. The method of claim 1, The gas flow path has a plurality of branches, the gas supply hole is provided only at the end of the branch, and each conductance from the inlet of the gas flow path to the gas supply hole is set substantially the same. Plasma processing apparatus characterized by. The method of claim 4, wherein And the cross-sectional area of the branch is substantially the same, and each length from the inlet of the gas flow path to the gas supply hole is set substantially the same. The method of claim 1, And an antenna block opposed to the mounting surface and provided to contact an inner surface of the processing chamber, wherein the high frequency antenna is provided in the antenna block. The method of claim 6, And said dielectric panel defining said shower head is positioned between said mounting surface and said high frequency antenna and constitutes an opposing wall of dielectric material of said antenna block facing said mounting surface. The method of claim 7, wherein And the antenna block includes a dielectric embedded layer separately from the opposing wall, and the high frequency antenna is embedded in the buried layer. The method of claim 8, And the antenna block is substantially solid between the inner surface of the processing chamber and the buried layer in contact with the antenna block. The method of claim 7, wherein And the antenna block forms a hollow and hermetic antenna chamber, and the apparatus includes an auxiliary machine for evacuating the antenna chamber and simultaneously setting the antenna chamber to a vacuum. The method of claim 10, And a pressure controller connected to the sub-discharge machine to maintain the differential pressure between the processing chamber and the antenna chamber below a predetermined value. The method of claim 1, And said processing vessel is made of a substantially conductive material. The method of claim 12, And a grounding means for grounding the processing vessel. In the apparatus for performing the treatment using a plasma to the substrate to be processed, A treatment vessel defining a confidential treatment chamber, A mounting table provided in the processing chamber and having a mounting surface for supporting the substrate to be processed; A main exhaust machine for evacuating the processing chamber and simultaneously setting the processing chamber to a vacuum; An antenna block facing the placing surface and installed to contact the inner surface of the processing chamber; A high frequency antenna installed in the antenna block for forming an electric field in the processing chamber above the mounting surface; A power supply unit for applying high frequency power to the high frequency antenna; A main supply system for supplying a processing gas into the processing chamber, at least a portion of the processing gas is prompted by the electric field to soften the plasma, and the main supply system is located between the mounting surface and the high frequency antenna. And a shower head defined by an opposing wall made of a dielectric material of the antenna block facing the placing surface, wherein the shower head has a gas flow passage formed substantially parallel to the placing surface, And a plurality of gas supply holes opening with respect to the plasma processing apparatus. The method of claim 14, The opposing wall substantially consists of a dielectric part and a hollow part including the gas flow path, and the projection areas of the solid part and the hollow part in the plane outer contour of the placing surface are A1 and A2, respectively. A2 / (A1 + A2) is set to less than 0.4, The plasma processing apparatus characterized by the above-mentioned. The method of claim 15, Said A2 / (A1 + A2) is 0.15-0. Plasma processing apparatus, characterized in that set to 25. The method of claim 14, And said gas flow path and said high frequency antenna are arranged to be substantially line-symmetrical or point-symmetrical with respect to the center of said mounting surface in the planar layout with respect to said mounting surface. The method of claim 14, The gas flow path has a plurality of branches, the gas supply hole is provided only at the end of the branch, and each conductance from the inlet of the gas flow path to the gas supply hole is set substantially the same. Plasma processing apparatus characterized by. The method of claim 18, And the cross-sectional area of the branch is substantially the same, and each length from the inlet of the gas flow path to the gas supply hole is set substantially the same. The method of claim 14, And the antenna block includes a dielectric embedding layer separately from the opposing inner wall, and the high frequency antenna is embedded in the buried layer. The method of claim 20, And the antenna block is substantially solid between the inner surface of the processing chamber and the buried layer in contact with the antenna block. The method of claim 14, And the antenna block forms a hollow and airtight antenna chamber, and the apparatus includes an exhausting machine for evacuating the antenna chamber and simultaneously setting the antenna chamber to a vacuum.