WO2021020502A1 - Gas nozzle and plasma processing device using same - Google Patents

Abstract

A gas nozzle according to the present disclosure includes a supply port to which a plasma generation gas is supplied, a discharge port through which the plasma generation gas is discharged toward a plasma space in which plasma is generated, and a flow path provided between the supply port and the discharge port. A cutting level difference Rδc₁ on a roughness curve of an end face located on a plasma space side is less than the cutting level difference Rδc₂ on a roughness curve of the outer peripheral surface connected to the end surface. The cutting level difference is the difference between the cutting level at a load length rate of 25% on the roughness curve and the cutting level at a load length rate of 75% on the roughness curve.

Description

Gas nozzle and plasma processing equipment using it

The present disclosure relates to a gas nozzle and a plasma processing apparatus using the gas nozzle.

Conventionally, in the manufacture of semiconductors, liquid crystals, etc., the object to be processed is treated using plasma in processes such as etching and film formation. In such a step, a corrosive gas containing a highly reactive halogen element (for example, fluorine, chlorine, etc.) is used. Therefore, high corrosion resistance is required for members that come into contact with corrosive gas or plasma used in manufacturing equipment such as semiconductors and liquid crystals. As such a member, for example, Patent Document 1 includes a columnar main body made of a ceramic sintered body having through holes through which gas flows, and a gas discharge port in the through holes is formed on one end surface of the main body. The gas nozzle is described. In the gas nozzle described in Patent Document 1, the average length (Rsm) of the contour curve element on one end surface is five times or more the average crystal grain size in the ceramic sintered body.

Japanese Patent No. 586591

The gas nozzle according to the present disclosure is between a supply port to which a plasma generation gas is supplied, a discharge port in which the plasma generation gas is discharged toward a plasma space in which plasma is generated, and a supply port and the discharge port. Includes a flow path provided in. The cutting level difference Rδc ₁ in the roughness curve of the end face located on the plasma space side is smaller than the cutting level difference Rδc ₂ in the roughness curve of the outer peripheral surface connected to the end face. The cutting level difference is the difference between the cutting level at a load length rate of 25% on the roughness curve and the cutting level at a load length rate of 75% on the roughness curve.

Further, the plasma processing apparatus according to the present disclosure includes the above gas nozzle.

(A) is an explanatory view showing a gas nozzle according to an embodiment of the present disclosure, (B) is an explanatory view seen from the arrow X direction of (A), and (C) is the arrow Y direction of (A). It is an explanatory diagram seen from.

In the gas nozzle used for the plasma processing apparatus, the end face exposed to plasma on the plasma space side of the outer surface of the gas nozzle is required to have higher corrosion resistance to plasma than other outer surfaces.

In the gas nozzle according to the present disclosure, as described above, the cutting level difference Rδc ₁ on the roughness curve of the end face located on the plasma space side is based on the cutting level difference Rδc ₂ on the roughness curve of the outer peripheral surface connected to the end face. Is also small. If the cutting level difference Rδc ₁ of the end face located on the plasma space side exposed to the space with high plasma density is small, it is difficult to deteriorate and the commercial value can be maintained for a long period of time. The cutting level difference (Rδc) is the difference in the height direction of the cutting levels C (Rrm1) and C (Rrm2) corresponding to the load length ratios Rmr1 and Rmr2 in the roughness curve defined by JIS B0601: 2001, respectively. Is. When the cutting level difference (Rδc) is large, the unevenness of the surface to be measured becomes large, and when it is small, the unevenness of the surface becomes small.

When the cutting level difference Rδc _{1 in} the roughness curve of the end face located on the plasma space side is smaller than the cutting level difference Rδc ₂ in the roughness curve of the outer peripheral surface connected to the end face, the end face located on the plasma space side The number of steep protrusions generated is relatively small. Therefore, the shedding generated from the tip of the convex portion is reduced, and the possibility that the shed particles are suspended in the plasma space is suppressed. In this case, the number of steep recesses generated in the end face located on the plasma space side is relatively small. Therefore, the shedding generated from the recesses is reduced, and the possibility that the shed particles float in the plasma space is suppressed. As a result, the possibility that the space having a high plasma density is contaminated is reduced, so that plasma processing such as film formation on a semiconductor wafer can be easily and high quality.

The gas nozzle according to the embodiment of the present disclosure will be described with reference to FIGS. 1 (A) to 1 (C). The gas nozzle 1 according to the embodiment shown in FIG. 1A has a supply port 2a to which the plasma generation gas is supplied and a discharge port 3a to discharge the plasma generation gas toward the plasma space where the plasma is generated. And a flow path provided between the supply port 2a and the discharge port 3a.

Of the supply ports 2a, the supply port 2a located on the inner peripheral side communicates with the discharge port 3a opened at the end face located on the plasma space side. The supply port 2a located on the outer peripheral side communicates with a discharge port (not shown) having four openings on the outer peripheral surface.

The gas nozzle 1 according to the embodiment has a substantially cylindrical shape in which a part of the outer peripheral surface is constricted. The size of the gas nozzle 1 according to the embodiment is not limited, and is formed in a desired size depending on the plasma processing apparatus provided. Specifically, the gas nozzle 1 according to the embodiment has a length of about 50 mm to 60 mm and a diameter of about 60 mm to 70 mm.

The gas nozzle 1 according to one embodiment is made of ceramics. Ceramics as a material is not limited, for _example, Y ₂ O 3 -ZrO ₂ system _ceramics, Y 2 _{O 3} system, like YAG-based ceramic. Among these, further improved corrosion resistance (the plasma resistance) with respect to the plasma, the mechanical strength because it can be more improved, may be used Y ₂ O ₃ -ZrO ₂ system ceramics. The ceramics in the present disclosure include polycrystalline bodies and single crystal bodies.

Examples of the Y ₂ O _3- ZrO ₂ type ceramics include ceramics such as (I) and (II) below.
(I) Ceramics containing yttrium zirconate as the main component.
(II) Ceramics having an yttrium oxide solid solution in which yttrium oxide is dissolved in yttrium oxide and a zirconium oxide solid solution in which yttrium oxide is dissolved in zirconium oxide as a main crystal phase.

The composition formula of yttrium zirconate is shown as, for example, YZrO ₃ , Zr ₃ Y ₄ O ₁₂ . Ceramics containing yttrium zirconate as a main component can be obtained, for example, by firing a mixture of yttrium oxide and zirconium oxide. The mixing ratio of yttrium oxide and zirconium oxide is not limited. For example, yttrium oxide contributes to the improvement of plasma resistance, and zirconium oxide contributes to the improvement of mechanical strength. Therefore, when the proportion of yttrium oxide is large, ceramics having plasma resistance superior to mechanical strength can be obtained. When the proportion of zirconium oxide is increased, ceramics having better mechanical strength than plasma resistance can be obtained.

In the semiconductor manufacturing apparatus member according to the embodiment, ceramics containing yttrium zirconate as a main component can be obtained, for example, by the following procedure. First, ceramics are obtained by firing a mixture of yttrium oxide and zirconium oxide. Additives generally contained in ceramics may be added to the mixture of yttrium oxide and zirconium oxide, if necessary.

Yttrium oxide solid solution of zirconium oxide in yttrium oxide solid solution, the ceramic yttrium oxide zirconium oxide to the zirconium oxide solid solution in which a solid solution as a main crystalline phase, and yttrium oxide composition formula is represented as Y ₂ O _3, The crystal structure is similar to that of zirconium oxide whose composition formula is represented as ZrO ₂ . Therefore, even if an X-ray diffractometer is used, the main diffraction peaks overlap, and it is difficult to identify each of them. Therefore, when a peak shift from the diffraction peak caused only by Y ₂ O _{3 in} which the diffraction angle 2θ appears at 20.5 ° to the high angle side is confirmed using an X-ray diffractometer, zirconium oxide is added to yttrium oxide. It can be considered that a solid solution of yttrium oxide is present.

On the other hand, the solid solution of zirconium oxide in which yttrium oxide is dissolved in zirconium oxide may be confirmed by using a scanning electron microscope (SEM) and an energy dispersive analyzer (EDS). As the ceramics containing yttrium aluminum composite oxide as a main component, for example, at least one of YAG, YAM and YAP is the main component.

YAG is shown as Al ₅ Y ₃ O ₁₂ , YAM is shown as Al ₂ Y ₄ O ₉ , and YAP is shown as Al YO ₃ . The main component in the present disclosure refers to a component that occupies 50% by mass or more of the total 100% by mass of the components constituting the ceramics, and is particularly preferably 60% by mass or more. Each component constituting the ceramics can be identified by using an X-ray diffractometer (XRD), and the mass ratio of each component can be determined by the Rietveld method using XRD.

In the gas nozzle 1 according to the embodiment, the supply port 2a is formed on the end face 2 on the side where the plasma generation gas is supplied when the gas nozzle 1 according to the embodiment is provided in the plasma processing apparatus. On the other hand, the discharge port 3a is formed on the end face 3 located on the plasma space side when the gas nozzle 1 according to the embodiment is provided in the plasma processing apparatus. The portion through which the plasma generation gas flows from the supply port 2a to the discharge port 3a serves as a flow path. Examples of the plasma generation gas include fluorine-based gases such as SF ₆ , CF ₄ , CHF ₃ , ClF ₃ , NF ₃ , C ₄ F ₈ , and HF, and chlorine such as Cl ₂ , HCl, BCl ₃ , and CCl _4. Examples include system gas.

The inner diameters of the supply port 2a and the discharge port 3a are set to a desired size according to the plasma processing device provided with the gas nozzle 1 according to the embodiment. Specifically, the supply port 2a and the discharge port 3a have an inner diameter of about 1 mm to 4 mm.

In the gas nozzle 1 according to the embodiment, the cutting level difference Rδc ₁ on the roughness curve of the end surface 3 located on the plasma space side is based on the cutting level difference Rδc ₂ on the roughness curve of the outer peripheral surface 4 connected to the end surface 3. Is also formed to be small. If the cutting level difference Rδc ₁ of the end face 3 exposed to the space with high plasma density is smaller than the cutting level difference Rδc ₂ in the roughness curve of the outer peripheral surface 4, it is less likely to deteriorate and the commercial value is maintained for a long period of time. Can be done.

As used herein, the term "cutting level difference" means the difference between the cutting level at a load length rate of 25% on the roughness curve and the cutting level at a load length rate of 75% on the roughness curve. .. The smaller the cutting level difference, the smoother the surface. In order to reduce the difference in cutting level, for example, surface irregularities may be reduced by polishing. In the gas nozzle 1 according to one embodiment, the end surface 3 is smoother than the outer peripheral surface 4.

If the cutting level difference Rδc ₁ on the roughness curve of the end surface 3 is smaller than the cutting level difference Rδc ₂ on the roughness curve of the outer peripheral surface 4, the difference between the cutting level difference Rδc ₁ and the cutting level difference Rδc ₂ is not limited. The difference between the cutting level difference Rδc ₁ and the cutting level difference Rδc ₂ may be 0.8 μm or more, and 1 μm or more and 1.4 μm or less in terms of further improving plasma resistance and further suppressing deterioration. May be good. The cutting level difference Rδc ₂ in the roughness curve of the outer peripheral surface 4 is, for example, 1 μm or more and 1.5 μm or less.

Further, in the gas nozzle 1 according to the embodiment, the root mean square height Rq ₁ of the end face 3 located on the plasma space side is formed to be smaller than the root mean square height Rq _{2 of the} outer peripheral surface 4 connected to the end face 3. It may have been. The smaller the root mean square height, the smoother the surface. When the root mean square height Rq _{1 of the} end face 3 is smaller than the root mean square height Rq _{2 of the} outer peripheral surface 4, plasma resistance can be further improved and deterioration can be further suppressed.

If the root mean square height Rq _{1 of the} end face 3 is smaller than the root mean square height Rq _{2 of the} outer peripheral surface 4, the difference between the root mean square height Rq ₁ and the root mean square height Rq ₂ is not limited. The difference between the root mean square height Rq ₁ and the root mean square Rq ₂ may be 0.8 μm or more, and 0.9 μm or more 1 in terms of further improving plasma resistance and suppressing deterioration. It may be 0.5 μm or less. The root mean square height Rq ₂ of the outer peripheral surface 4 is, for example, 0.9 μm or more and 1.5 μm or less.

If the root mean square slope RΔ _q1 of the end face 3 is smaller than the root mean square slope RΔ _{q2 of} the outer peripheral surface 4, the difference between the root mean square slope RΔ _q1 and the root mean square slope RΔ _q2 is not limited. The difference between the root mean square RΔ _q1 and the root mean square RΔ _q2 may be 0.5 or more, and 0.55 or more and 0.8 or less in terms of further improving plasma resistance and suppressing deterioration. There may be. Root mean square slope Aruderuta _q2 of the outer peripheral surface 4 is, for example, 0.6 or more and 1 or less.

Cut level difference Aruderutashi, root mean square height Rq and root mean square slope Aruderuta _q is, JIS B 0601: conforms to 2001, a laser microscope (KEYENCE manufactured, ultra-deep color 3D profile measuring microscope (VK-X1000 or It can be measured using the successor model)). The measurement conditions are coaxial epi-illumination for illumination, 240 times for measurement magnification, no cutoff value λs, 0.08 mm for cutoff value λc, correction of termination effect, and end face 3 and outer peripheral surface 4 to be measured. The measurement range per location is 1404 μm × 1053 μm. For each measurement range, four lines to be measured are drawn along the longitudinal direction at approximately equal intervals, and line roughness is measured for each of these lines. Calculated cut level difference Rδc obtained from each line, a mean value for each measurement range of root mean square height Rq and root mean square slope Aruderuta _q, may be compared average.

Hereinafter, an example of the gas nozzle manufacturing method according to the present disclosure will be described. Specifically, first, a mixture of a powder containing yttrium oxide as a main component and a powder containing zirconium oxide as a main component (hereinafter, a powder containing yttrium oxide as a main component and a powder containing zirconium oxide as a main component is referred to as "ceramic powder". After adding pure water and a dispersant, the mixture is pulverized and mixed with a bead mill to obtain a slurry. The ceramic powder includes a powder containing yttrium oxide as a main component and a powder containing zirconium oxide as a main component, and a powder containing zirconium oxide as a main component and a powder containing yttrium oxide as a main component, for example. It is mixed in a mass ratio of 5 to 3.1. With this mass ratio, ceramics can be obtained in which plasma resistance and mechanical strength are exhibited in a well-balanced manner.

After adding an organic binder to the obtained slurry and stirring it, the slurry is sequentially spray-dried and deironed to obtain granules. After filling the granules in a molding die, a molded product is obtained by pressure molding into a columnar shape using a molding method such as a uniaxial pressure molding method or a cold hydrostatic pressure molding method (CIP molding method). Next, the molded product is cut to obtain a precursor. By sequentially degreasing and firing this precursor, ceramics (sintered body) containing yttrium zirconate as a main component can be obtained.

The firing atmosphere is an atmospheric atmosphere, the firing temperature is 1640 ° C. or higher and 1880 ° C. or lower, the holding time is 1.5 hours or more and 5 hours or less, and natural cooling may be performed in the temperature lowering process.

In order to obtain a ceramic (sinter) having a main crystal phase of an yttrium oxide solid solution in which zirconium oxide is dissolved in yttrium oxide and a zirconium oxide solid solution in which yttrium oxide is dissolved in zirconium oxide, for example, in the above temperature lowering process. It may be annealed. The annealing treatment may be performed, for example, at a temperature of 1300 ° C. or higher and 1500 ° C. or lower for 3 hours or more and 5 hours or less.

Ceramics (single crystal) containing yttrium aluminum composite oxide as a main component can be obtained, for example, by the following procedure. First, a powder containing yttrium oxide as a main component and a powder containing aluminum oxide as a main component are heated and melted in a crucible made of molybdenum, and then the EFG method, Czochralski method, Cairoporous method, TGT method or HEM method. A columnar or cylindrical ingot is obtained by crystallization with. Here, the atmospheric gas in the melting may be argon gas, the melting temperature may be 1550 ° C. to 1850 ° C., and the pressure of the argon gas may be 0.02 to 0.06 MPa.

Grinding such as honing is performed along the axial direction of the obtained sintered body or ingot to form a flow path. When honing is used, diamond abrasive grains having a particle size number of # 3000 or more described in JIS R 6001-2: 2017 may be used as the abrasive grains. By polishing the end face of the sintered body or ingot with diamond abrasive grains having an average particle size (D ₅₀ ) of 1 μm or more and 3 μm or less, an end face located on the plasma space side can be obtained, and the gas nozzle of the present disclosure can be obtained. Can be obtained.

To obtain a gas nozzle in which the difference between the cutting level difference Rδc ₁ and the cutting level difference Rδc ₂ is 1 μm or more, for example, the following procedure is obtained. First, a flow path is formed by honing using diamond abrasive grains having a particle size number of # 3000 or more and # 6000 or less. Next, an end face located on the plasma space side is formed by a polishing process using diamond abrasive grains having an average particle size (D ₅₀ ) of 1 μm or more and 3 μm or less.

To obtain a gas nozzle in which the root mean square height Rq ₁ of the end face located on the plasma space side is smaller than the root mean square height Rq _{2 of the} outer peripheral surface connected to the end face, for example, is obtained by the following procedure. First, a flow path is formed by honing using diamond abrasive grains having a particle size number of # 3000 or more and # 6000 or less. Next, an end face located on the plasma space side is formed by a polishing process using diamond abrasive grains having an average particle size (D ₅₀ ) of 1 μm or more and 2 μm or less.

To obtain a gas nozzle in which the difference between the root mean square height Rq ₁ and the root mean square height Rq ₂ is 0.8 μm or more, for example, the following procedure is obtained. First, a flow path is formed by honing processing using diamond abrasive grains having a particle size number of # 4000 or more and # 6000 or less. Next, an end face located on the plasma space side is formed by a polishing process using diamond abrasive grains having an average particle size (D ₅₀ ) of 1 μm or more and 2 μm or less.

The gas nozzle according to the present disclosure is provided in the plasma processing apparatus. Specifically, the gas nozzle according to the present disclosure is used, for example, as a nozzle for supplying plasma generation gas to the plasma space (space in the chamber) of the plasma processing apparatus.

The gas nozzle according to the present disclosure is not limited to the above-described embodiment. For example, the gas nozzle 1 described above has a substantially cylindrical shape in which a part of the outer peripheral surface is constricted. However, the shape of the gas nozzle according to the present disclosure is not limited to a columnar shape. The gas nozzle according to the present disclosure may have, for example, an elliptical columnar column, a prismatic columnar column (for example, a triangular columnar column, a square columnar column, a pentagonal columnar column, a hexagonal columnar column, etc.) in addition to the columnar column, depending on the plasma processing apparatus. ..

1 Gas nozzle 2 End face on the side where plasma generation gas is supplied 2a Supply port 3 End face located on the plasma space side 3a Discharge port 4 Outer surface

Claims (10)

1. The supply port to which the plasma generation gas is supplied and
   The discharge port where the plasma generation gas is discharged toward the plasma space where plasma is generated, and
   A flow path provided between the supply port and the discharge port,
   Including
   The cutting level difference Rδc ₁ in the roughness curve of the end face located on the plasma space side is smaller than the cutting level difference Rδc ₂ in the roughness curve of the outer peripheral surface connected to the end face.
   The cutting level difference is the difference between the cutting level at a load length rate of 25% on the roughness curve and the cutting level at a load length rate of 75% on the roughness curve.
   Gas nozzle.
2. The gas nozzle according to claim ₁ , wherein the difference between the cutting level difference Rδc ₁ and the cutting level difference Rδc ₂ is 0.8 μm or more.
3. The gas nozzle according to claim 1 or 2, wherein the root mean square height Rq ₁ of the end face located on the plasma space side is smaller than the root mean square Rq _{2 of the} outer peripheral surface connected to the end face.
4. The gas nozzle according to claim 3, wherein the difference between the root mean square height Rq ₁ and the root mean square Rq ₂ squared is 0.8 μm or more.
5. The gas nozzle according to any one of claims 1 to 4, wherein the root mean square slope RΔ _q1 of the end face located on the plasma space side is smaller than the root mean square RΔ _{q2 of the} outer peripheral surface connected to the end face.
6. The gas nozzle according to claim 5, wherein the difference between the root mean square slope RΔ _q1 and the root mean square slope RΔ _q2 is 0.5 or more.
7. The gas nozzle according to any one of claims 1 to 6, wherein the ceramic contains a ceramic containing yttrium zirconate as a main component.
8. The ceramics according to any one of claims 1 to 6, which include ceramics containing an yttrium oxide solid solution in which zirconium oxide is dissolved in yttrium oxide and a zirconium oxide solid solution in which zirconium oxide is dissolved in zirconium oxide as a main crystal phase. The described gas nozzle.
9. The gas nozzle according to any one of claims 1 to 6, wherein the ceramic contains a ceramic containing yttrium aluminum composite oxide as a main component.
10. A plasma processing apparatus including the gas nozzle according to any one of claims 1 to 9.

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