WO2002058127A1

WO2002058127A1 - Plasma treatment device, baffle plate, and method of manufacturing the baffle plate

Info

Publication number: WO2002058127A1
Application number: PCT/JP2002/000430
Authority: WO
Inventors: Takashi Kobayashi
Original assignee: Tokyo Electron Limited
Priority date: 2001-01-22
Filing date: 2002-01-22
Publication date: 2002-07-25

Abstract

A plasma treatment device (1) of parallel flat plate type, wherein a baffle plate (24) for enclosing plasma in a plasma generating area above a chamber is formed of a plurality of plate members (25) stuck on each other, the plate members (25) are bent in a specified pattern, and, for example, hexagonal holes (24a) are formed between the plate members (25) adjacent to each other, whereby the baffle plate (24) can have a large number of honeycomb-shaped holes (24a) on the entire area thereof.

Description

TECHNICAL FIELD The present invention relates to a plasma processing apparatus, a paffle plate and a method for manufacturing the same.

The present invention relates to a plasma processing apparatus for performing a predetermined plasma processing on an object to be processed, a paffle plate, and a method for manufacturing the same. Background art

In the manufacturing processes of semiconductor devices, liquid crystal display devices, and the like, plasma processing apparatuses that use plasma to process the surfaces of these substrates are used. Examples of the plasma processing apparatus include a plasma etching apparatus for etching a substrate and a plasma CVD apparatus for performing chemical vapor deposition (CVD). Among them, flat plate type plasma processing apparatuses are widely used because of their excellent processing uniformity and relatively simple apparatus configuration.

The parallel plate type plasma processing apparatus includes a champer, a susceptor 7 ° which is provided in the champ and constitutes a lower electrode, and an upper electrode which is provided in parallel to the susceptor and faces the susceptor and constitutes a processing gas outlet. And power. During processing, the object to be processed is placed on the susceptor, and the processing gas is supplied from the upper electrode to the object to be processed. By applying high-frequency power to the upper and lower electrodes, plasma of a processing gas is generated, and a predetermined processing is performed on the surface of the object to be processed.

The plasma processing apparatus includes a paffle plate for closing the plasma in a space between the lower electrode and the upper electrode. The paffle plate is formed of a ring-shaped disk-shaped member having an opening at the center, in which a number of narrow openings are formed. The paffle plate is arranged so that a cylindrical susceptor passes through the opening. The paffle plate is formed by cutting, punching, or the like a narrow opening having a shape such as a slit or a round hole on an aluminum plate or the like. The narrow mouth allows gas to pass, but prevents the passage of plasma. As a result, the plasma density above the paffle plate (in the vicinity of the object to be processed) is increased, and the plasma use efficiency is increased. Here, during the plasma processing, the inside of the champer is evacuated by an exhaust device and maintained at a pressure of about a vacuum. When the pressure is exhausted through the baffle plate, a pressure difference is generated above and below the baffle plate in the chamber. Such pressure differences have an unfavorable effect on processing and reduce reliability. For example, when embedding an insulating film in a wiring groove, if the pressure difference is large, a void is formed in the insulating film, so that the so-called embedding characteristic is reduced. For this reason, it is important to increase the conductance of the paffle plate and reduce the pressure difference.

To increase the conductance of the baffle plate, the aperture of the baffle plate (the ratio of the total area of the narrow mouth to the total area of the surface of the baffle plate) may be increased. For this purpose, the slit length may be increased or the number of round holes may be increased. However, the higher the aperture, the lower the mechanical strength of the paffle plate, and the more easily the deformation occurs. This reduces the reliability of the process, such as uneven plasma density distribution. In addition, to prevent this, the frequency of baffle plate replacement is increased, and the productivity is reduced. Since the plate is also a flow path for high-frequency current, if the slit length is increased, the loss of high-frequency power increases and the processing characteristics deteriorate.

As described above, the conventional Paffuru plate, high conductance, and not having a high mechanical strength, both, high processing reliability and productivity ^ ¹ production there is a risk that not performed. Disclosure of the invention

In view of the above circumstances, an object of the present invention is to provide a plasma processing apparatus, a paffle plate, and a method for manufacturing the same, which can perform processing with high reliability and high productivity.

In order to achieve the above object, a plasma processing apparatus (1) according to a first aspect of the present invention comprises:

Champa (2) and

An installation table (8) for installing an object to be processed in the champer (2);

A gas for processing is supplied onto the surface of the object to be processed, and is connected to a high frequency power source (22) to generate plasma of the gas by applying high frequency power from the high frequency power source (22). A diffusion electrode (16); A plate-like member (24) having a cylindrical hole (24a) extending substantially perpendicular to the main surface thereof, for confining the plasma in the vicinity of the object;

Is provided.

In the above configuration, for example, the plate member (24) has a surface perpendicular to the main surface of the plate member (24), and is configured by combining a plate material (25) bent in a predetermined pattern. ing.

In the above configuration, for example, the plate member (24) is configured by combining a plurality of annular plate members (25) having different diameters from each other.

In the above configuration, for example, the hole (24a) has a polygonal cross section. In the above configuration, for example, the ratio of the total area of the openings formed by the holes (24a) to the main surface of the plate-like member (24) is 50% to 100%.

In the above configuration, for example, the thickness of the plate (25) is 0.5 mm to 1.0 mm.

In the above configuration, for example, at least a portion of the plate-shaped member (24) that comes into contact with the plasma is made of any of aluminum, anodized aluminum, aluminum, and yttria.

In order to achieve the above object, a paffle plate (24) according to a second aspect of the present invention has a cylindrical hole (24) extending substantially perpendicular to the main surface thereof, which prevents the passage of plasma and allows the passage of gas. a) a plate-like member having

In the above configuration, for example, the puffing plate (24) has a surface perpendicular to a main surface thereof, and is configured by combining plate members (25) bent in a predetermined pattern.

In the above configuration, for example, the baffle plate (24) is configured by combining a plurality of annular plate members (25) having different diameters.

In the above configuration, for example, the hole (24a) has a polygonal cross section. In the above configuration, for example, a ratio of a total area of the opening formed by the hole (24a) to the main surface with respect to an area of the main surface of the paffle plate (24) is 50% to 100%. In the above configuration, for example, the thickness of the plate material (25) is 0.5 mm to 1.0 mm.

In the above configuration, for example, at least a portion of the puffing plate (24) that comes into contact with the plasma is made of any one of aluminum, anodized aluminum, aluminum, and yttria.

To achieve the above object, a method for manufacturing a baffle plate (24) according to a third aspect of the present invention includes:

A method for producing a paffle plate (24) that prevents the passage of plasma and allows the passage of gas,

A step of laminating a plurality of annular plate members (25) bent in a predetermined pattern and having different diameters from each other in a direction perpendicular to the main surface of the plate member (25); BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a configuration of a plasma processing apparatus according to the present embodiment.

FIG. 2A shows a plan view of the baffle plate shown in FIG. 1, and FIG. 2B shows an enlarged view of the baffle plate shown in FIG. 2A.

Fig. 3A shows the results of examining the pressures above and below the baffle plate when using a honeycomb-type baffle plate, and Fig. 3B shows the results when the slit-type baffle plate was used. The results of examining the pressures above and below are shown.

Fig. 4A shows the results of examining the pressure above the paffle plate by changing the aperture ratio of the honeycomb-type paffle plate. Fig. 4B shows the relationship between the pressure above the paffle plate and the formation of voids. The result of the examination is shown.

FIG. 5 shows the results of examining the relationship between the opening ratio of the honeycomb type, the slit type, and the round hole type baffle plate, and the deposition rate.

FIG. 6 shows a modification of the paffle plate. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a plasma processing apparatus according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a semiconductor wafer (hereinafter referred to as a wafer W) has a C VD (Chemi A parallel flat plate type plasma processing apparatus for forming a silicon dioxide (Si〇F) film by calvapor deposition will be described as an example.

FIG. 1 shows a configuration of a plasma processing apparatus 1 according to the present embodiment. The plasma processing apparatus 1 includes a cylindrical chamber 2 made of, for example, aluminum whose surface is anodized (anodized). Chamber 2 is grounded.

An exhaust port 3 is formed on the bottom side of the champer 2. An exhaust device 4 is connected to the exhaust port 3. The exhaust device 4 is constituted by a vacuum pump such as a turbo-molecular pump, and evacuates the interior of the champer 2 to a predetermined reduced-pressure atmosphere, for example, a pressure of 0.01 Pa or less. Further, a gate pulp 5 is provided on a side wall of the champer 2, and while the gate pulp 5 is open, ノ and W are conveyed to and from an adjacent load lock chamber (not shown).

A substantially cylindrical susceptor support 6 for mounting a wafer W is provided at the center of the bottom of the chamber 2. A susceptor 8 is provided on the susceptor support 6 via an insulator 7 such as a ceramic. The susceptor 8 is made of a conductor such as aluminum and constitutes a lower electrode of the parallel plate electrode. The susceptor support 6 is connected to an elevating mechanism (not shown) provided below the champ 2 via a shaft 9 so that the susceptor can be raised and lowered.

The lower part of the susceptor support 6 is covered with bellows 1.0 made of stainless steel or the like. The bellows 10 has its upper end and lower end screwed to the lower portion of the susceptor support 6 and the bottom surface of the champer 2, respectively. The bellows 10 expands and contracts as the susceptor support 6 moves up and down, and maintains the airtight state in the chamber 2.

A lower refrigerant channel 11 is provided inside the susceptor support base 6, and the refrigerant circulates through the lower refrigerant channel 11 in the lower refrigerant channel 11. The cold heat of the refrigerant is transferred to the wafer W via the susceptor 8, and the processing surface of the Ueno and W is set to a desired temperature.

The susceptor support 6 is provided with lift pins 13 for transferring the wafer W. The lift pins 13 can be moved up and down by a cylinder (not shown). On the susceptor 8, an electrostatic chuck (not shown) having substantially the same diameter as the wafer W is provided. The electrostatic chuck fixes the wafer W placed on the susceptor 8 by Coulomb force.

The susceptor 8 is connected to a first high-frequency power supply 14 via a first matching unit 15. The first high-frequency power supply 14 has a frequency in the range of 0.1 to 13 MHz, and by applying a frequency in such a range, the wafer W to be processed is damaged. And an appropriate ionic action can be provided.

Above the susceptor 8, an upper electrode 16 is provided so as to face the susceptor 8 in parallel. The upper electrode is fixed to the upper part of the chamber 2 via the insulating material 17. The upper electrode 16 is made of a conductive material such as aluminum. An upper refrigerant passage 18 is provided inside the upper electrode 16. The refrigerant circulates through the upper refrigerant flow path 18 via the upper refrigerant introduction pipe 19, and the upper electrode 16 is controlled to a desired temperature.

Further, a gas supply pipe 20 is connected to the upper electrode 16, and is connected to a processing gas supply source 21 outside the champer 2. The processing gas from the processing gas supply source 21 is supplied to a hollow portion (not shown) formed inside the upper electrode 16 via a gas supply pipe 20. The processing gas supplied into the upper electrode 16 is diffused in the hollow portion, and is discharged to the wafer W from a gas discharge port 16 a provided on a surface of the upper electrode 16 facing the susceptor 8. The treatment gas, various of even the can employ conventionally used in the formation of S I_〇_F film, for _{example, S i F 4, S i} H 4, as a dilution gas and 〇 ₂ gas Ar gas can be used.

A second high-frequency power supply 22 is connected to the upper electrode 16 via a second matching device 23. The second high-frequency power source 22 has a frequency in the range of 13 to 150 MHz, and by applying such a high frequency, the dissociation state and the high density A plasma is formed.

A paffle plate 24 is provided on the side wall of the champer 2. The paffle plate 24 may be fixed to the susceptor support 6. The notch plate 24 has a large number of holes 24 a, and traps the plasma of the processing gas generated between the susceptor 8 and the upper electrode 16 in the upper part of the champer 2 (near the wafer W). Also, the paffle plate 24 It also has a function of flowing a return current of high-frequency power from the surface of the baffle plate 24 to the wall surface of the champ 2 and returning it to the upper electrode 16 side.

FIG. 2A is a plan view of the puff hole plate 24. FIG. As shown in the figure, the paffle plate 24 is composed of a disc-shaped member having an opening 24 b at the center. The outer circumference of the paffle plate 24 has substantially the same diameter as the inner circumference of the cylindrical chamber 2, and the opening 24 b has substantially the same diameter as the outer circumference of the susceptor support 6. Therefore, the paffle plate 24 is formed so as to surround the susceptor support 6 and substantially cover the space between the side wall of the chamber 2 and the susceptor support 6.

The baffle plate 24 is configured by laminating a plurality of annular plate members 25 having different diameters so that the main surface thereof is substantially perpendicular to the main surface of the paffle plate 24. Fig. 2B shows an enlarged view of a part of the paffle plate 24. As shown in the figure, the plate member 25 is formed of a band-shaped aluminum plate having a predetermined width and bent into a pattern in which a substantially trapezoidal shape is repeated.

The paffle plate 24 is configured such that adjacent plate members 25 are adhered to each other at the trapezoidal bottom of the pattern. As a result, in the space between the adjacent plate members 25, a hexagonal hole 24 a is formed in the horizontal direction on the main surface of the plate member 25, and a large number of The hole 24a is formed in a honeycomb shape or a honeycomb shape. Here, for example, the plate member 25 has a thickness of 0.5 mm to 1.0 mm, and the hole 24a is configured to have a hexagonal cross section with a side of about 4 mm. Is done. Further, the aperture ratio of the baffle plate 24 (total cross-sectional area of the hole 24 a Z cross-sectional area of the baffle plate 24 X 100) is, for example, 60%. Here, all the holes 24a have substantially the same diameter, and are formed so that the cross-sectional area of each 24a is substantially constant.

The honeycomb-type paffle plate 24 described above has relatively low mechanical strength. That is, since the plurality of plate members 25 are bonded together, the mechanical strength in the direction perpendicular to the main surface of the baffle plate 24 (the direction horizontal to the main surface of the plate member 25) is relatively high. . For example, it is apparent that higher resilience and mechanical strength can be obtained as compared with a case where holes are formed by punching or the like in a plate such as an annealed miniature.

Further, since the holes 24 a are formed between the adjacent plate members 25, the interval between the holes 24 a is equal to that of the two plate members 25 in any part of the paffle plate 24. Thickness That's it. Therefore, the baffle plate 24 should have a desired aperture ratio of approximately 100% while maintaining high mechanical strength by changing the thickness and the like of the plate member 25. Can be.

As described above, by using the paffle plate 24 formed by laminating the plurality of plate members 25, a desired conductance in the champ 2, particularly, above the puffing plate 24, is obtained, and the reliability is improved. High processing becomes possible. Furthermore, even if the aperture ratio of the paffle plate 24 is increased to obtain a desired conductance, the mechanical strength is high, so that the baffle plate 24 is unlikely to be deformed and the processing reliability is improved. Sexual decline is prevented.

(Examples) 'The results of examining the processing characteristics and the like in the case of using the honeycomb type paffle plate 24 are shown below.

Fig. 3A shows the results of examining the difference in pressure between the upper and lower parts of the paffle plate 24 when nitrogen (N ₂ ) gas was flowed into the champer 2 equipped with the honeycomb-type paffle plate 24. Show. The aperture ratio of the baffle plate 24 was 60%. Fig. 3B shows the results when a slit-type paffle plate was used. The aperture ratio of the slit-type paffle plate was set to 16%, at which the best processing characteristics were obtained.

As shown in Fig. 3A, when the honeycomb type is used, the pressure difference above and below the baffle plate is small even if the flow rate of nitrogen is increased. In particular, when the gas flow rate is less than 500 sccm, there is almost no pressure difference.

On the other hand, as shown in Fig. 3B, when the slit type is used, the pressure difference above and below the baffle plate increases as the nitrogen flow rate increases. In particular, when the gas flow rate is more than 200 sccm, a large pressure difference occurs.

From the above, it can be seen that when a honeycomb-type baffle plate 24 having an aperture ratio of 60% is used, sufficient conductance is ensured, and a large pressure difference does not occur above and below the baffle plate 24.

FIG. 4A shows the pressure change above the baffle plate 24 when the film formation gas is flown into the champer 2 having the honeycomb-type paffle plate 24 and the aperture ratio is changed. Here, 'The film forming conditions are as follows: SiH ₄ / SiF 4 / O 2 / A r = 25/25/25 0/50 sccm, High-frequency power of 60 MHz, 2.7 kW and 2 MHz, 0.3 kW are applied to the upper electrode 16 and the susceptor (lower electrode) 8, the processing temperature is 380 ° C, and the gap between the electrodes is 25 mm.

As shown in the figure, as the aperture ratio of the baffle plate 24 increases, the pressure above the paffle plate 24, that is, the pressure in the plasma generation space, decreases. Also, it can be seen that when the aperture ratio is about 50% or more, the gradient of the pressure change becomes small. Therefore, when the aperture ratio is 50% or more, the pressure in the plasma generation space is stabilized at less than about 1 Pa. FIG. 4B shows the results of examining the pressure above the paffle plate 24 and the occurrence of voids when the film forming process (CVD process) was performed under the above conditions. Here, the void refers to a void formed in a concave portion when a predetermined film is formed on a wafer having an uneven surface, and the formation of a void indicates a so-called decrease in filling characteristics.

As shown in FIG. 4B, a poid is generated as the pressure is higher, and a poid is generated when the pressure is 1 Pa or more. Therefore, in addition to the results shown in FIG. 4A, it can be seen that the opening ratio should be about 50% or more in order to perform processing with no voids and good filling characteristics.

Fig. 5 shows the results of examining the relationship between the opening ratio and the deposition rate when using slit, round hole, and honeycomb type paffle plates. Here, film formation _{conditions, S iH 4 / S i F} 4/0 2 / A r = 25/25/250/50 sc cm, the upper electrode 16 60 M Hz, 2. 7 kW susceptor (lower electrode) A high-frequency power of 2 MHz and 0.3 kW was applied to 8, the processing temperature was 380 ° C, and the gap between the electrodes was 25 mm.

As shown in FIG. 5, when the slit type is used, when the aperture ratio is 20% or more, the film forming speed is significantly reduced. This is because the inner circumference of the slit becomes longer and the loss of high frequency power increases due to the increase in the slit length.

In addition, when the round hole type and the non-cam type are used, the film forming speed is slightly decreased with an increase in the aperture ratio, but the loss of the high frequency power is small, and the film forming speed is kept high. However, although the honeycomb type can be made up to 80% of the opening ratio, the round hole type cannot make the opening ratio more than 50% from the viewpoint of mechanical strength. From the results shown in FIGS. 4A and 4B, it is known that under these conditions, good processing characteristics can be obtained when the aperture ratio is 50% or more. Therefore, only when the honeycomb type is used, A film forming process with a high film forming rate and good embedding characteristics is possible.

As described above, the plasma processing apparatus 1 of the present embodiment includes the paffle plate 24 having a structure in which a plurality of plate members 25 are bonded. The aperture ratio of the paffle plate 24 can be up to about 80% while maintaining high mechanical strength. Therefore, a desired conductance (aperture ratio) can be realized, and a highly reliable process with good embedding characteristics and the like can be performed. In addition, since the mechanical strength is high, the frequency of replacement due to deformation or the like is low, and a decrease in productivity can be avoided.

The present invention is not limited to the above embodiment, and various modifications and applications are possible. Hereinafter, modifications of the above-described embodiment applicable to the present invention will be described.

In the above embodiment, the paffle plate 24 (the plate member 25) is made of aluminum. The material of the paffle plate 24 is not limited to this, and may be any conductive material having high plasma resistance, such as alumina, yttria, and the like. It may be composed of a material. In the above embodiment, the hole 24 a of the baffle plate 24 has a hexagonal shape. The shape is not limited to this, but may be any shape by changing the pattern of the plate members 25 to be bonded. For example, a polygon other than a hexagon or a waveform as shown in FIG. 6 may be used.

The hole 24a of the puff / drill plate 24 is formed to have a substantially constant cross-sectional area. However, the holes 24 a may be formed or arranged in any way on the main surface of the paffle plate 24 as long as the holes 24 a achieve a predetermined opening ratio as a whole. For example, in order to form a gas flow that can be processed with high uniformity, the cross-sectional area of the hole 24 a may be changed, for example, from the inside to the outside of the baffle plate 2.

In the above-described embodiment, a parallel plate type plasma processing apparatus formed by CVD for forming a SiOF film on a semiconductor wafer has been described. However, the type of film to be formed is not limited thereto, S I_〇 ₂ film, may be of any type CF film. Further, the plasma treatment performed on the object to be processed can be used for a film formation process other than CVD, an etching process, and the like. Further, the plasma processing apparatus is not limited to the parallel plate type, but may be a magnetron type, an inductively coupled type, an ECR (Electron Cyclotron Resonance). Any type, such as a mold, may be used. Further, the object to be processed is not limited to a semiconductor wafer, and may be used for a liquid crystal display device or the like. Industrial applicability.

INDUSTRIAL APPLICABILITY The present invention can be suitably applied to a processing apparatus that performs a plasma processing such as a film forming process and an etching process on a processing target such as a semiconductor wafer. -The present invention is based on Japanese Patent Application No. 2001-13573 filed on Jan. 22, 2001, and includes the description, the claims, the drawings, and the abstract. The disclosure in the above application is incorporated herein by reference in its entirety.

Claims

The scope of the claims

1. Champa (2),

A mounting table (8) for mounting an object to be processed in the champer (2);

A diffusion electrode that supplies a processing gas onto the surface of the object to be processed, is connected to a high-frequency power supply (22), and generates plasma of the gas by applying high-frequency power from the high-frequency power supply (22); (1 6) and

A plate-like member (24) having a cylindrical hole (24a) extending substantially perpendicular to the main surface thereof, for closing the plasma in the vicinity of the object;

A plasma processing apparatus (1), comprising:

2. The plate-like member (24) has a surface perpendicular to the main surface of the plate-like member (24), and is configured by combining plate members (25) bent in a predetermined pattern. The plasma processing apparatus (1) according to claim 1, wherein:

3. The plasma processing apparatus (1) according to claim 2, wherein the plate-shaped member (24) is configured by combining a plurality of annular plate members (25) having different diameters from each other. .

4. The plasma processing apparatus according to claim 2, wherein the hole (24a) has a polygonal cross section.

5. The ratio of the total area of the opening formed by the hole (24a) to the main surface with respect to the area of the main surface of the plate-like member (24) is 50% to 100%. The plasma processing apparatus (1) according to claim 2.

6. The plasma processing apparatus (1) according to claim 3, wherein the thickness of the plate (25) is 0.5 mm to 1.0 mm.

7. The plate-like member (24), wherein at least a portion of the plate-shaped member (24) that comes into contact with the plasma is made of aluminum, anodized aluminum, alumina or yttria, or any one of them. The described plasma processing apparatus (1).

8. It is composed of a plate-like member that has a cylindrical hole (24a) that extends substantially vertically on its main surface and that allows the passage of gas while preventing the passage of plasma. Paffle plate to be (24).

9. The paffle plate (24) has a surface perpendicular to the main surface thereof, and is configured by combining a plate material (25) bent in a predetermined pattern. Paffle plate as described (24).

10. The paffle plate (24) according to claim 8, wherein the paffle plate (24) is formed by combining a plurality of annular plate members (25) having different diameters from each other.

11. The paffle plate (24) according to claim 8, wherein the hole (24a) has a polygonal cross section.

12. The ratio of the total area of the opening formed by the hole (24a) to the main surface of the paffle plate (24) to the area of the main surface is 50% to 100%. The paffle plate (24) according to claim 8.

13. The paffle plate (24) according to claim 9, wherein the thickness of the plate (25) is 0.5 mm to 1.0 mm.

14. The paffle plate according to claim 8, wherein at least a portion of the paffle plate (24) that comes into contact with the plasma is made of any one of aluminum, anodized aluminum, alumina, and yttria. (twenty four) .

15. A method of manufacturing a baffle plate (24) that prevents the passage of plasma and allows the passage of gas,

A baffle plate comprising a step of laminating a plurality of annular plate members (25) bent in a predetermined pattern and having mutually different diameters in a direction perpendicular to a main surface of the plate member (25) and laminating them. (24) Manufacturing method.