Composite structures and semiconductor manufacturing apparatus equipped with composite structures

Abstract

To provide a composite structure used as a member of a semiconductor manufacturing apparatus, and the semiconductor apparatus including the same, the semiconductor manufacturing apparatus being capable of enhancing a low-particle generation.SOLUTION: A composite structure includes a base material and a structure that is arranged on the base material and has a surface. The structure includes Y4Al2O9 as a main component and has a nano-indentation hardness of 6.0 GPa or more. The composite structure has an excellent particle resistance, and is preferably used as a member of a semiconductor manufacturing apparatus.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a composite structure with excellent particle resistance (low-particle generation), which is preferably used as a component for semiconductor manufacturing equipment, and to a semiconductor manufacturing equipment equipped therewith. [Background technology]

[0002] A technique is known in which ceramics are coated onto the surface of a substrate to impart functionality to it. For example, components for semiconductor manufacturing equipment used in plasma irradiation environments, such as semiconductor manufacturing equipment, have a highly plasma-resistant coating formed on their surface. The coating can be made of oxide ceramics such as alumina (Al2O3) or yttria (Y2O3), or fluorides such as yttrium fluoride (YF3) or yttrium oxyfluoride (YOF).

[0003] Furthermore, oxide-based ceramics include erbium oxide (Er2O3) or Er3Al5O 12 , gadolinium oxide (Gd2O3) or Gd3Al5O 12 Yttrium aluminum garnet (YAG:Y3Al5O 12 Alternatively, proposals have been made to use a protective layer made of Y4Al2O9 or the like (Patent Documents 1 and 2). With the miniaturization of semiconductors, higher levels of particle resistance are required for various components within semiconductor manufacturing equipment. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Special Publication No. 2016-528380 [Patent Document 2] Special Publication No. 2017-514991 [Overview of the project] [Problems that the invention aims to solve]

[0005] The inventors have now discovered a correlation between the hardness of a structure containing yttrium and aluminum oxide Y4Al2O9 (hereinafter abbreviated as "YAM") as the main component and its particle resistance, which is an indicator of particle contamination associated with plasma corrosion. As a result, they have succeeded in creating a structure with excellent particle resistance.

[0006] Therefore, the present invention aims to provide a composite structure with excellent particle resistance (low-particle generation). Furthermore, it aims to provide this composite structure as a component for semiconductor manufacturing equipment, and semiconductor manufacturing equipment using it. [Means for solving the problem]

[0007] Furthermore, the composite structure according to the present invention is a composite structure comprising a base material and a structure provided on the base material and having a surface, characterized in that the structure contains Y4Al2O9 as a main component and has an indentation hardness greater than 6.0 GPa.

[0008] Furthermore, the composite structure according to the present invention is intended for use in environments where particle resistance is required.

[0009] Furthermore, the semiconductor manufacturing apparatus according to the present invention is equipped with the composite structure according to the present invention described above. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view of a member having a structure according to the present invention. [Figure 2] This graph shows the relationship between the depth from the surface of the structure and the fluorine atom concentration after standard plasma test 1. [Figure 3] This graph shows the relationship between the depth from the surface of the structure and the fluorine atom concentration after standard plasma test 2. [Figure 4] These are SEM images of the surface of the structure after standard plasma tests 1 and 2.

Best Mode for Carrying Out the Invention

[0011] composite structure The basic structure of the composite structure according to the present invention will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view of a composite structure 10 according to the present invention. The composite structure 10 is composed of a structure 20 provided on a base material 15, and the structure 20 has a surface 20a.

[0012] The structure 20 included in the composite structure according to the present invention is a so-called ceramic coat. By applying the ceramic coat, various physical properties and characteristics can be imparted to the base material 15. In this specification, the structure (or ceramic structure) and the ceramic coat are used synonymously unless otherwise specified.

[0013] [[ID=!!!!]]

[0014] Base material It should be noted that there seems to be an error in the original text where the line break tag is repeated as in the translation. I have corrected it as best as possible based on the rules. If this is not what you intended, please double-check the original text.In the present invention, the substrate 15 is not particularly limited as long as it is used for its intended purpose, and is composed of, for example, alumina, quartz, anodized aluminum, metal, glass, etc., and is preferably composed of alumina. According to a preferred embodiment of the present invention, the arithmetic mean roughness Ra (JIS B0601: 2001) of the surface of the substrate 15 on which the structure 20 is formed is, for example, less than 5 micrometers (μm), preferably less than 1 μm, more preferably less than 0.5 μm.

[0015] structure In the present invention, the structure contains YAM as a main component. Also, according to one embodiment of the present invention, YAM is a polycrystal.

[0016] In the present invention, the main component of the structure refers to a compound that is relatively more contained than other compounds contained in the structure 20 by quantitative or semi-quantitative analysis by X-ray diffraction (XRD) of the structure. For example, the main component is the compound most contained in the structure, and the ratio occupied by the main component in the structure is greater than 50% in terms of volume ratio or mass ratio. The ratio occupied by the main component is more preferably greater than 70%, and also preferably greater than 90%. The ratio occupied by the main component may be 100%.

[0017] In the present invention, components that the structure may contain in addition to YAM include oxides such as yttrium oxide, scandium oxide, europium oxide, gadolinium oxide, erbium oxide, ytterbium oxide, and fluorides such as yttrium fluoride and yttrium oxyfluoride, and may contain two or more of these.

[0018] In the present invention, the structure is not limited to a single-layer structure and may be a multi-layer structure. It is also possible to have a plurality of layers having different compositions and having YAM as a main component, and another layer, for example, a layer containing Y2O3, may be provided between the substrate and the structure.

[0019] Indentation hardness In the present invention, the structure containing YAM as the main component has an indentation hardness greater than 6.0 GPa. This improves particle resistance. In a preferred embodiment of the present invention, the indentation hardness is 9 GPa or higher, more preferably 10 GPa or higher, and even more preferably 11 GPa or higher. The upper limit of the indentation hardness is not particularly limited and may be determined by the required characteristics, but for example, it is 20 GPa or less.

[0020] Here, the indentation hardness of the structure is measured by the following method. Specifically, the hardness measurement is performed by a micro-indentation hardness test (nanoindentation) on the surface of the structure containing YAM as the main component on the substrate. The indenter is a Berkovich indenter, and the indentation depth is fixed at 200 nm, and the indentation hardness (indentation hardness) H IT Measure the H on the surface. IT Select a surface that excludes scratches and dents as the measurement point. More preferably, the surface should be a polished smooth surface. The number of measurement points should be at least 25. The 25 or more measured points H IT The average value of these values ​​shall be defined as the hardness in this invention. Other test and analytical methods, procedures for verifying the performance of the test equipment, and conditions required for standard reference samples shall conform to ISO 14577.

[0021] In semiconductor manufacturing equipment, highly corrosive fluorine-based plasmas using CF-based gases or SF-based gases are employed. Structures containing YAM as the main component according to the present invention exhibit minimal changes in crystal structure even when exposed to such fluorine-based plasmas and fluorinated. Therefore, it is believed that changes in the crystal structure of the structure surface can be suppressed even when used in a corrosive plasma environment, making it possible to achieve even lower particle levels.

[0022] According to one aspect of the present invention, when the YAM contained in the structure is polycrystalline, its average crystallite size is, for example, less than 100 nm, preferably less than 50 nm, more preferably less than 30 nm, and most preferably less than 20 nm. A small average crystallite size makes it possible to reduce the size of particles generated by the plasma.

[0023] In this specification, "polycrystalline material" refers to a structure formed by the bonding and accumulation of crystalline particles. Preferably, the crystalline particles constitute a crystal substantially by themselves. The diameter of the crystalline particles is, for example, 5 nanometers (nm) or larger.

[0024] In this invention, crystallite size is measured, for example, by X-ray diffraction. The average crystallite size can be calculated using Scherrer's formula as follows. D = Kλ / (βcosθ) Here, D is the crystallite size, β is the peak full width at half maximum (in radians (rad)), θ is the Bragg angle (in rad), and λ is the wavelength of the characteristic X-ray used in the XRD.

[0025] In Scherrer's equation, β is calculated as β = (βobs - βstd). βobs is the full width at half maximum (FMAX) of the X-ray diffraction peak of the sample being measured, and βstd is the FMAX of the X-ray diffraction peak of the standard sample. K is Scherrer's constant.

[0026] In YAM, the X-ray diffraction peaks that can be used to calculate the crystallite size are the peak around the diffraction angle 2θ = 26.7° attributed to Miller index (hkl) = (013), the peak around the diffraction angle 2θ = 29.6° attributed to Miller index (hkl) = (122), and the peak around the diffraction angle 2θ = 30.6° attributed to Miller index (hkl) = (211), among others, in the monoclinic form of YAM.

[0027] Alternatively, crystallite size may be calculated from images obtained by observation using a transmission electron microscope (TEM). For example, the average value of the equivalent circle diameter of the crystallites can be used as the average crystallite size.

[0028] In embodiments where YAM is polycrystalline, the spacing between adjacent crystallites is preferably 0 nm or more and less than 10 nm. The spacing between adjacent crystallites refers to the closest spacing between crystallites and does not include voids formed by multiple crystallites. The spacing between crystallites can be determined from images obtained by observation using TEM.

[0029] Fluorine penetration depth According to a preferred embodiment of the present invention, a composite structure comprising the present invention exhibits preferable particle resistance if, when exposed to a specific fluorine-based plasma, the fluorine atom concentration at a predetermined depth from the surface is less than a predetermined value. The composite structure according to this embodiment of the present invention satisfies the fluorine atom concentration at each of the depths from the surface shown below after being exposed to a fluorine-based plasma under the following two conditions. In the present invention, the tests of exposure to a fluorine-based plasma under the two conditions will be referred to as standard plasma tests 1 and 2, respectively.

[0030] Standard plasma tests 1 and 2 simulate various conditions expected within semiconductor manufacturing equipment. Standard plasma test 1 is a test condition in which bias power is applied, and the structure is used as a component such as a focus ring located around the silicon wafer inside the chamber, and is exposed to a corrosive environment due to radical and ion collisions. Standard plasma test 1 evaluates performance against SF6 plasma. On the other hand, standard plasma test 2 is a test condition in which no bias is applied, and the structure is used as a side wall component located approximately perpendicular to the silicon wafer inside the chamber, or as a top plate component facing the silicon wafer, and is exposed to a corrosive environment with few ion collisions and mainly due to radicals. According to a preferred embodiment of the present invention, the composite structure according to the present invention satisfies a predetermined value for fluorine concentration in at least one of these tests.

[0031] (1) Plasma exposure conditions For structures containing YAM as the main component on a substrate, the surface is exposed to a plasma atmosphere using an inductively coupled reactive ion etching (ICP-RIE) apparatus. The plasma atmosphere formation conditions are as follows:

[0032] Standard plasma test 1: The process gas used is SF6100 sccm, and the power output consists of a 1500W coil output for the ICP and a 750W bias output.

[0033] Standard plasma test 2: The process gas is SF6100 sccm, the power output is 1500W for the ICP coil, and the bias output is OFF (0W). In other words, no high-frequency power is applied to the electrostatic chuck bias.

[0034] Common to Standard Plasma Tests 1 and 2, the chamber pressure is 0.5 Pa and the plasma exposure time is 1 hour. The member for the semiconductor manufacturing apparatus is placed on a silicon wafer adsorbed by an electrostatic chuck provided in the inductively coupled reactive ion etching apparatus so that the surface of the structure is exposed to the plasma atmosphere formed under this condition.

[0035] (2) Method for measuring the fluorine atom concentration in the depth direction on the surface of a structure For the surface of the structure after Standard Plasma Tests 1 to 2, using X-ray photoelectron spectroscopy (XPS), the atomic concentration (%) of fluorine (F) atoms with respect to the sputtering time was measured by depth-direction analysis using ion sputtering. Subsequently, in order to convert the sputtering time into depth, the step (s) between the sputtered portion and the non-sputtered portion by ion sputtering was measured with a stylus surface profiler. The depth (e) per sputtering unit time was calculated as e = s / t from the step (s) and the total sputtering time (t) used for the XPS measurement, and the sputtering time was converted into depth using the depth (e) per sputtering unit time. Finally, the depth from the surface 20a and the atomic concentration (%) of fluorine (F) atoms at that depth position were calculated.

[0036] In this aspect, the composite structure according to the present invention satisfies the fluorine atom concentration at the depth from each of the following surfaces after the above-mentioned Standard Plasma Tests 1 and 2.

[0037] After Standard Plasma Test 1: The fluorine atom concentration F1 at a depth of 10 nm from the surface 10nm is less than 3.0%, more preferably, F1 10nm is 1.5% or less, and even more preferably, F1 10nm is 1.0% or less.

[0038] After Standard Plasma Test 2: The fluorine atom concentration F3 at a depth of 10 nm from the surface 10nm is less than 3.0%, more preferably, F3 10nm is 1.0% or less, and even more preferably, F3 10nm is 0.5% or less.

[0039] Manufacturing of composite structures The composite structure according to the present invention may be manufactured by various purposeful manufacturing methods, as long as a structure having the above-described lattice constant can be realized on a substrate. That is, it may be manufactured by a method that can form a structure containing Y4Al2O9 as the main component and having the above-described lattice constant on a substrate, for example, the structure can be formed on the substrate by physical vapor deposition (PVD) or chemical vapor deposition (CVD). Examples of PVD methods include electron beam physical vapor deposition (EB-PVD), ion beam assisted deposition (IAD), electron beam ion assisted deposition (EB-IAD), ion plating, and sputtering. Examples of CVD methods include thermal CVD, plasma CVD (PECVD), organometallic CVD (MOCVD), mist CVD, laser CVD, and atomic layer deposition (ALD). Furthermore, according to another aspect of the present invention, it can be formed by arranging fine particles of a brittle material or the like on the surface of a substrate and applying a mechanical impact force to the fine particles. Methods for "applying mechanical impact force" include using high-speed rotating, high-hardness brushes or rollers, or pistons that move up and down at high speed, utilizing the compressive force produced by shock waves generated during an explosion, applying ultrasound, or a combination of these.

[0040] Furthermore, the composite structure according to the present invention can preferably be formed by the aerosol deposition method (AD method). The AD method involves injecting an aerosol, which is a mixture of fine particles containing brittle materials such as ceramics dispersed in a gas, from a nozzle toward a substrate. The fine particles collide with the substrate, such as metal, glass, ceramics, or plastic, at high speed. The impact of this collision causes deformation and fracture of the brittle material fine particles, thereby joining them together and directly forming a structure (ceramic coating) containing the constituent materials of the fine particles on the substrate, for example, as a layered or film-like structure. This method does not require heating or cooling means, and the structure can be formed at room temperature, and a structure with mechanical strength equal to or greater than that of a fired body can be obtained. In addition, by controlling the conditions for impacting the fine particles, the shape and composition of the fine particles, it is possible to vary the density, mechanical strength, and electrical properties of the structure in various ways. The composite structure according to the present invention can be manufactured by setting the various conditions described below so that the indentation hardness is satisfied in order to realize the composite structure according to the present invention.

[0041] In this specification, "fine particles" means particles with an average particle size of 5 micrometers (μm) or less, as identified by particle size distribution measurement or scanning electron microscopy, when the primary particles are dense particles. When the primary particles are porous particles that are easily broken by impact, it means particles with an average particle size of 50 μm or less.

[0042] Furthermore, in this specification, "aerosol" refers to a solid-gas mixed phase in which the aforementioned fine particles are dispersed in a gas (carrier gas) such as helium, nitrogen, argon, oxygen, dry air, or a mixture of these gases, and also includes cases where "aggregates" are present, but preferably refers to a state in which the fine particles are substantially dispersed individually. The gas pressure and temperature of the aerosol may be set arbitrarily considering the physical properties of the desired structure, but the concentration of fine particles in the gas is preferably in the range of 0.0003 mL / L to 5 mL / L at the time of injection from the discharge port, when the gas pressure is converted to 1 atmosphere and the temperature to 20 degrees Celsius.

[0043] The aerosol deposition process is typically carried out at room temperature, and structures can be formed at a temperature well below the melting point of the particulate material, i.e., below several hundred degrees Celsius. In this specification, "room temperature" means a temperature significantly lower than the sintering temperature of the ceramics, and substantially refers to a room temperature environment of 0 to 100°C. In this specification, "powder" refers to the state in which the aforementioned particulate matter has naturally aggregated. [Examples]

[0044] The present invention will be further described by the following examples, but the present invention is not limited to these examples.

[0045] The materials used for the structures in the examples are shown in the table below. [Table 1]

[0046] In the table, the median diameter (D50 (μm)) is the diameter representing 50% of the cumulative particle size distribution for each raw material. The diameter of each particle was determined using a circular approximation.

[0047] Multiple samples were prepared by varying the combination of these raw materials and film formation conditions (type and flow rate of carrier gas, etc.) to create structures on substrates. The particle resistance of the obtained samples was evaluated after standard plasma tests 1 and 2. In this example, the aerosol deposition method was used to prepare the samples.

[0048] [Table 2]

[0049] As shown in the table, nitrogen (N2) or helium (He) is used as the carrier gas. The aerosol is obtained by mixing the carrier gas with the raw material powder (raw material fine particles) in the aerosol generator. The resulting aerosol is then injected from a nozzle connected to the aerosol generator towards the substrate placed inside the film-forming chamber due to the pressure difference. At this time, the air inside the film-forming chamber is exhausted to the outside by a vacuum pump.

[0050] sample Each of the structures obtained as described above contained polycrystalline YAM as its main component, and the average crystallite size in all of these polycrystalline structures was less than 30 nm.

[0051] XRD was used to measure the crystallite size. Specifically, the "X'PertPRO / Panalytical" XRD instrument was used. The XRD measurement conditions were as follows: characteristic X-ray CuKα (λ=1.5418Å), tube voltage 45kV, tube current 40mA, step size 0.0084°, and time per step 80 seconds or more. The average crystallite size was calculated using Scherrer's formula. A value of 0.94 was used for K in Scherrer's formula.

[0052] The main components of the crystalline phase of YAM on the substrate were measured by XRD. The XRD instrument used was "X'PertPRO / Panalytical". The XRD measurement conditions were: characteristic X-ray CuKα (λ=1.5418Å), tube voltage 45kV, tube current 40mA, step size 0.0084°, and time per step 80 seconds or more. The XRD analysis software "High Score Plus / Panalytical" was used to calculate the main components. The relative intensity ratio obtained by performing a peak search on the diffraction peak using the quasi-quantitative value (RIR = Reference Intensity Ratio) listed on the ICDD card was used. For polycrystalline YAM in the case of multilayer structures, it is desirable to use measurement results from a depth region of less than 1 μm from the outermost surface using thin-film XRD.

[0053] Standard plasma testing Furthermore, standard plasma tests 1 and 2 were performed on samples 1 to 5 under the conditions described above, and the particle resistance after these tests was evaluated using the following procedure. A "Muc-21 Rv-Aps-Se / Sumitomo Precision Products" ICP-RIE apparatus was used. For both standard plasma tests 1 and 2, the chamber pressure was 0.5 Pa and the plasma exposure time was 1 hour. The samples were placed on silicon wafers adsorbed by an electrostatic chuck provided in an inductively coupled reactive ion etching apparatus so that their surface was exposed to the plasma atmosphere formed under these conditions.

[0054] Measurement of indentation hardness The indentation hardness of structures on a substrate was evaluated using a nanoindentation test (micro-indentation) according to the following procedure. The "ENT-2100 / Elionix" nanoindenter was used. For the nanoindentation test, a Berkovich indenter was used, the test mode was set to a set indentation depth, and the indentation depth was set to 200 nm. Indentation hardness (indentation hardness) H IT H was measured. ITMeasurement points were randomly set on the surface of the structure, with at least 25 measurement points. The measurement points were determined from the 25 or more H IT The average value was used as the hardness. The results are shown in Table 2.

[0055] Measurement of fluorine penetration depth For the surface of samples after standard plasma tests 1 and 2, the atomic concentration (%) of fluorine (F) atoms relative to sputtering time was measured using X-ray photoelectron spectroscopy (XPS) for depth profiling with ion sputtering. A K-Alpha / Thermo Fisher Scientific XPS instrument was used. Next, to convert sputtering time to depth, the step difference (s) between the sputtered and unsputtered areas was measured using a stylus-type surface profile analyzer. From the step difference (s) and the total sputtering time (t) used for XPS measurement, the depth per unit time (e) was calculated using the formula e = s / t, and the sputtering time was converted to depth using this depth per unit time (e). Finally, the depth from the sample surface and the fluorine (F) atomic concentration (%) at that depth were calculated.

[0056] The depth from the structural surface and the fluorine atom concentration after standard plasma tests 1 and 2 were as shown in the table below. After standard plasma test 1: [Table 3] After standard plasma test 2: [Table 4]

[0057] Furthermore, the above data can be shown as graphs in Figures 2 and 3.

[0058] SEM image SEM images of the structure surface after standard plasma tests 1 and 2 were taken as follows. Specifically, the corrosion state of the plasma-exposed surface was evaluated using a scanning electron microscope (SEM). The SEM used was a "SU-8220 / Hitachi, Ltd." The acceleration voltage was set to 3kV. The resulting images are shown in Figure 4.

[0059] Surface roughness (arithmetic mean height Sa) The surface roughness of the structure after standard plasma test 1 was evaluated using a laser microscope to determine the arithmetic mean height (Sa) as defined in ISO 25178. An Olympus OLS4500 laser microscope was used. An MPLAPON100XLEXT objective lens was used, with a cutoff value λc of 25 μm. The results are shown in the table below. [Table 5]

[0060] Evaluation of Results Based on the above results, in Table 2 above, the evaluation was as follows: "◎" if the effect of plasma corrosion was small in both Standard Plasma Test 1 and 2, "〇" if the effect of plasma corrosion was small in either Standard Plasma Test 1 or 2, and "×" if the effect of plasma corrosion was present in both conditions of Standard Plasma Test 1 and 2.

[0061] Embodiments of the present invention have been described above. However, the present invention is not limited to these descriptions. Modifications made by those skilled in the art to the above-described embodiments are also included within the scope of the present invention, as long as they retain the features of the present invention. For example, the shape, dimensions, material, and arrangement of structures, base materials, etc., are not limited to those exemplified and can be modified as appropriate. Furthermore, the elements of each of the above-described embodiments can be combined to the extent technically feasible, and combinations thereof are also included within the scope of the present invention, as long as they retain the features of the present invention. [Explanation of symbols]

[0062] 10... Composite structures, 15... Base materials, 20... Structures, 20a... Surfaces of structures

Claims

1. A composite structure for use in an environment where particle resistance to corrosive fluorine-based plasma is required, comprising a base material and a structure provided on the base material and having a surface, The aforementioned structure is Y ４ Al ２ O ９ It contains as its main component, and its indentation hardness is greater than 6.0 GPa. A composite structure obtained by using an inductively coupled reactive ion etching (ICP-RIE) apparatus, exposing it to a plasma atmosphere for 1 hour in an environment with SF6 100 sccm as the process gas, an ICP coil output of 1500 W as the power output, bias output OFF (0 W), and chamber pressure of 0.5 Pa, and having a fluorine atom concentration F3 10 nm at a depth of 10 nm from the surface less than 3.0%.

2. The composite structure according to claim 1, wherein the indentation hardness is 9.0 GPa or higher.

3. The composite structure according to claim 1, wherein the indentation hardness is 10 GPa or more.

4. The composite structure according to claim 1, wherein the indentation hardness is 11 GPa or more.

5. The composite structure according to any one of claims 1 to 3, wherein the average crystallite size of the structure is less than 50 nm.

6. A composite structure according to any one of claims 1 to 5, which is a component for semiconductor manufacturing equipment.

7. A semiconductor manufacturing apparatus comprising a composite structure according to any one of claims 1 to 5.

8. A method for operating a semiconductor manufacturing apparatus using a corrosive fluorine-based plasma, A method characterized by installing a composite structure according to any one of claims 1 to 5 at a location exposed to the corrosive fluorine-based plasma, thereby suppressing the generation of particles by suppressing the penetration of fluorine into the composite structure by the corrosive fluorine-based plasma.

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