TW201731013A - Member for semiconductor manufacturing apparatus, method for producing the same, and heater including shaft - Google Patents

Abstract

A member for a semiconductor manufacturing apparatus according to the present invention is a member that is to be joined to an aluminum nitride base member. The member is composed of a composite material including principal constituent phases that are aluminum nitride and a pseudopolymorph of aluminum nitride which includes silicon, aluminum, oxygen, and nitrogen. The pseudopolymorph of aluminum nitride has at least one periodic structure selected from a 27R phase and a 21R phase or an X-ray diffraction peak at least at 2[Theta]=59.8 DEG to 60.8 DEG. The composite material has a thermal conductivity of 50 W/mK or less at room temperature.

Description

Element for semiconductor manufacturing apparatus, method of manufacturing the same, and heater having the shaft

The present invention relates to an element for a semiconductor manufacturing apparatus, a method of manufacturing the same, and a heater having a shaft.

Conventionally, a heater having a shaft includes a ceramic wafer holding portion having a resistance heating element and a support for supporting the wafer holding portion. As such a heater having a shaft, it is proposed that the thermal conductivity of the support is lower than that of the wafer holding portion (refer to Patent Document 1). Specifically, it is disclosed that a wafer holding portion made of AlN having a thermal conductivity of 170 W/mK is bonded to a support made of AlN having a thermal conductivity of 80 W/mK or a mullite having a thermal conductivity of 4 W/mK. A heater having a shaft for the support. The difference in thermal expansion coefficient between the wafer holding portion and the support is 0.1 to 0.5 ppm/° C. With respect to such a holder, it is described that the uniformity of the entire surface of the holding wafer is measured to be within ±0.5%.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1 Japanese Patent No. 4311910

However, a support body made of AlN having a thermal conductivity of 80 W/mK was bonded to a wafer holding portion glass made of AlN having a thermal conductivity of 170 W/mK. The heater of the shaft is difficult to be said to be sufficiently high. Further, a heater having a shaft made of a mullite support having a thermal conductivity of 4 W/mK is bonded to a wafer holding portion glass made of AlN having a thermal conductivity of 170 W/mK, which is excellent in soaking property but rich in The problem of low corrosion resistance of the mullite support. In particular, the antimony component contained in the mullite has extremely low corrosion resistance to a halogen gas, and is etched during use, and is a source of generation of particles.

The present invention has been made to solve such a technical problem. The main object of the present invention is to provide an element for a semiconductor manufacturing apparatus, which can improve the soaking property of the aluminum nitride-based element when bonded to an aluminum nitride-based device. It is sufficiently high and excellent in corrosion resistance.

The element for a semiconductor manufacturing apparatus according to the first aspect of the invention is a device for a semiconductor manufacturing device bonded to an aluminum nitride-based device, and a composite material containing aluminum nitride and pseudopolymorphs as a main constituent phase is used as a material. Wherein the foregoing aluminum nitride pseudopolymorph comprises bismuth, aluminum, oxygen and nitrogen, and the aluminum nitride pseudopolymorph has a periodic structure of at least one of a 27R phase and a 21R phase, and the heat conduction at room temperature of the composite material The rate is 50 W/mK or less.

The aluminum nitride pseudopolymorph contained in the element for semiconductor manufacturing apparatus is a low thermal conductivity 27R phase and/or a 21R phase, and the room temperature thermal conductivity is as low as 50 W/mK or less. Therefore, when the element for semiconductor manufacturing apparatus is bonded to the aluminum nitride-based element, heat dissipation of the aluminum nitride-based element can be suppressed to the element for a semiconductor manufacturing apparatus. Therefore, the element for semiconductor manufacturing apparatus can sufficiently increase the soaking property of the aluminum nitride-based element. Or can be from aluminum nitride Thermal insulation of the components. Further, since the thermal expansion coefficient of the pseudopolymorph is similar to that of the aluminum nitride-based element, the thermal expansion coefficient of the composite material is also close to that of the aluminum nitride-based element. Further, the element for a semiconductor manufacturing apparatus is superior in corrosion resistance to an element containing a large amount of a ruthenium component such as mullite. Furthermore, aluminum nitride and aluminum nitride pseudopolymorphs are the main constituent phases, and the constituent phases confirmed by the X-ray diffraction pattern (XRD profile) are observed in the order of high peak intensity, indicating aluminum nitride and nitriding. One of the aluminum pseudopolymorphs is the highest and the other is the second highest. Further, the periodic structure is an Al-containing layer or a layer containing Al and Si in a hexagonal layered structure, and is laminated in a predetermined order with the N-containing layer or the N-containing and O-containing layers.

The second semiconductor manufacturing apparatus element of the present invention is a device for a semiconductor manufacturing device bonded to an aluminum nitride-based device, and a composite material containing aluminum nitride and an aluminum nitride pseudopolymorph as a main constituent phase is used as a material. The aluminum nitride pseudopolymorph includes bismuth, aluminum, oxygen and nitrogen, and the X-ray diffraction peak of the aluminum nitride pseudopolymorph exhibits at least 2θ=59.8~60.8°, and the thermal conductivity of the composite material is 50 W at room temperature. Below mK.

This semiconductor device manufacturing element has an aluminum nitride pseudopolymorph having a low thermal conductivity of at least 2θ=59.8 to 60.8° with an X-ray diffraction peak, and the thermal conductivity at room temperature is as low as 50 W/mK or less. Therefore, when the element for semiconductor manufacturing apparatus is bonded to the aluminum nitride-based element, heat dissipation of the aluminum nitride-based element can be suppressed to the element for a semiconductor manufacturing apparatus. Therefore, the element for semiconductor device manufacturing can sufficiently increase the soaking property of the aluminum nitride-based element. Or it is possible to thermally insulate the heat from the aluminum nitride-based element. Furthermore, since the thermal expansion coefficient of the pseudopolymorph is similar to that of the aluminum nitride component, the thermal expansion coefficient of the composite is also close to that of aluminum nitride. System component. Further, the element for a semiconductor manufacturing apparatus is superior in corrosion resistance to an element containing a large amount of a ruthenium component such as mullite.

Further, the pseudopolymorph is a group of materials having a crystal structure of AlN (2H) as a matrix, a portion of intrinsic Si of Al, and a structure of O in a part of N, and a periodic structure of AlN. A group of materials that change gradually. The pseudopolymorph has 27R phase (SiAl ₈ O ₂ N ₈ ), 21R phase (SiAl ₆ O ₂ N ₆ ), 12H phase (SiAl ₅ O ₂ N ₅ ), and 15R phase (SiAl ₄ O) from the side of the AlN. ₂ N ₄ ) and so on. The first and second semiconductor manufacturing apparatus elements of the present invention are not particularly limited as long as they are joined to the aluminum nitride-based element in the semiconductor manufacturing apparatus, and are, for example, a susceptor or a plate material such as a heater or an electrostatic chuck. . In addition, the aluminum nitride-based element is an element mainly composed of aluminum nitride (for example, 70% by mass or more based on the total mass of aluminum and nitrogen).

In the first and second semiconductor device manufacturing apparatuses of the present invention, it is preferable that at least one element of tantalum and oxygen is dissolved in the aluminum nitride of the composite material. In this case, the thermal conductivity of the aluminum nitride crystal itself can be made small, and the proportion of the pseudopolymorph introduced as the composite phase can be reduced. When the proportion of the pseudopolymorph is small, there is an advantage that the thermal expansion coefficient of the composite material is smaller from the aluminum nitride. Moreover, in the corrosion resistance of halogen plasma, the pseudopolymorph is also slightly worse than aluminum nitride. Therefore, since the ratio of the pseudopolymorph is small, high corrosion resistance can be obtained, which is preferable.

In the first and second semiconductor manufacturing apparatus elements of the present invention, when the total mass of Al, N, Si, and O is 100, the mass ratio of Al, N, Si, and O of the composite material is preferably Al. :N:Si:O=59~63:29~34:1~5:2~8. When the mass ratio of each element is within this range, the thermal conductivity of the element for a semiconductor manufacturing apparatus can be surely 50 W/mK or less. When using Al, N, Si, O When the total mass is 100, the mass ratio of Al, N, Si, and O of the composite material is more preferably Al: N: Si: O = 59.6 - 62.7: 29.9 - 33.1: 1.5 - 4.5: 2.7 - 7.1.

In the first and second semiconductor device manufacturing apparatus according to the present invention, the composite material contains at least one of an oxide of a rare earth metal and an oxynitride of a rare earth metal, and an element other than the rare earth metal When the total mass is 100, the mass ratio of the rare earth metal is preferably more than 0 and 3.0 or less. In this case, since the rare earth metal element-containing component promotes sintering of the composite material, a dense composite material can be produced at normal pressure. Further, regardless of the presence or absence of a rare earth metal element, sintering is carried out under a pressure such as hot pressing or hot pressing (HIP), and there is no problem in obtaining a dense composite material.

In the first and second semiconductor manufacturing device elements of the present invention, the thermal conductivity of the composite material at 550 ° C is preferably 30 W/mK or less. In this case, it is particularly effective for an element used for a heater element or the like at a high temperature.

In the first and second semiconductor manufacturing apparatus elements of the present invention, the composite material preferably has a thermal expansion coefficient of from 40 to 1000 ° C of 5.5 to 6.0 ppm/° C. In this case, since the difference in thermal expansion coefficient from aluminum nitride is small, the stress due to the mismatch of the thermal expansion coefficient when the aluminum nitride-based device is bonded is reduced, and the bonding state can be favorably maintained. In particular, an element that repeatedly heats and cools like a heater can be an element that is less likely to cause cracks.

In the first and second semiconductor manufacturing device elements of the present invention, the opening ratio of the composite material is preferably 0.5% or less. In this case, the surface of the element can be finished to be smooth, and gas leakage in the vicinity of the joint portion of the composite material itself with other materials can be prevented from occurring. Further, it becomes an element which is highly resistant to particles caused by contact with the halogen plasma.

In the first and second semiconductor manufacturing apparatus elements of the present invention, the four-point bending strength of the composite material is preferably 250 MPa or more. In this case, the strength of the ceramic element used in the existing semiconductor manufacturing apparatus is equal to or higher than that of the ceramic element used in the conventional semiconductor manufacturing apparatus.

A method of manufacturing an element for a semiconductor manufacturing apparatus of the present invention is It is mixed so that the aluminum nitride is 81 to 95% by mass, the alumina is 3 to 13% by mass, and the tantalum nitride is 2 to 9% by mass with respect to the total mass of aluminum nitride, aluminum oxide, and tantalum nitride. The powder is blended, and the blended powder is molded to form a molded body, and the molded body is fired at 1750 to 1850 ° C to obtain an element for a semiconductor manufacturing apparatus as described above.

According to this manufacturing method, the element for a semiconductor manufacturing apparatus of any of the above can be manufactured relatively easily. For example, in the case of normal pressure firing, after the blended powder is subjected to uniaxial press forming, pressure equalization press forming, extrusion molding or cast molding, the formed body is placed in a firing furnace in an inert atmosphere (nitrogen gas, Under argon, etc., it is fired at a normal temperature of 1750~1850 °C. Further, in the case of hot-pressing, the blended powder may be formed into a molded body by uniaxial press molding or the like, and the molded body may be stored in a film for firing and in a vacuum atmosphere or an inert atmosphere. It is fired at a pressure of 100 to 400 kgf/cm ² and a temperature of 1750 to 1850 °C. In the case where the shape of the element for a semiconductor manufacturing apparatus is complicated, it is preferable to use normal pressure firing. The blended powder is preferably a total mass of aluminum nitride, aluminum oxide and tantalum nitride, and is 81.4 to 94.2% by mass of aluminum nitride, 3.0 to 12.6% by mass of alumina, and 2.8 to 8.2% by mass of tantalum nitride. The way to mix.

In the method for producing an element for a semiconductor manufacturing apparatus of the present invention, a rare earth oxide may be added as a sintering aid component to the blended powder. Examples of the rare earth oxides include Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Dy ₂ O ₃ , Ho ₂ O ₃ , and Er. ₂ O ₃ , Yb ₂ O ₃ and the like. Among them, Y ₂ O ₃ and Yb ₂ O _{3 are} preferred. When the amount of the rare earth oxide added is too large, the thermal expansion coefficient of the composite material is high, and the amount of addition is preferably 3% by mass or less based on the mass of the entire blended powder.

The heater having a shaft according to the present invention includes a shaft which is an element for any of the above semiconductor manufacturing apparatuses, and a wafer supporting heater which is joined to the shaft and which uses an aluminum nitride-based material as a material.

According to this, the heater having the shaft can sufficiently increase the heat uniformity of the wafer supporting heater. Further, the shaft itself can be shortened by the low thermal conductivity of the shaft portion, and the heater having the shaft can be made small. Further, the corrosion resistance is more excellent.

In the heater having a shaft according to the present invention, the difference in thermal expansion coefficient between the shaft and the wafer supporting heater of 40 to 1000 ° C is preferably 0.3 ppm / ° C or less. In this case, since no thermal stress is generated in the joint portion or even if it is generated, it is possible to suppress the occurrence of cracks by repeating heating and cooling.

In the heater having a shaft according to the present invention, preferably, the bonding layer for bonding the shaft and the wafer supporting heater comprises aluminum nitride, spinel, and rare earth oxyfluoride. The rare earth oxyfluoride is preferably YOF, LaOF, CeOF, NdOF, TbOF, YbOF, LuOF or the like, and particularly preferably YOF or YbOF.

10‧‧‧With shaft heater

20‧‧‧ Wafer Support Heater

22‧‧‧ Impedance heating body

22a‧‧‧End

22b‧‧‧The other end

23‧‧‧Table electrode

24‧‧‧1 hole

26‧‧‧2nd hole

30‧‧‧Cylinder shaft

32‧‧ ‧ paragraph difference

34‧‧‧Great Path Department

34a, 36a‧‧ ‧ flange

36‧‧‧Little Trails Department

38‧‧‧Power pole

40‧‧‧ joint layer

Fig. 1 is a cross-sectional view showing the heater 10 having a shaft.

Fig. 2 is a perspective view of the cylindrical shaft 30.

Fig. 3 is a view showing the XRD topography of the sintered body material of Experimental Example 1.

Fig. 4 is a view showing the XRD topography of the sintered body material of Experimental Example 2.

Fig. 5 is a view showing the XRD topography of the sintered body material of Experimental Example 3.

Fig. 6 is a view showing the XRD topography of the sintered body material of Experimental Example 5.

Fig. 7 is a view showing the XRD topography of the sintered body material of Experimental Example 11.

Fig. 8 is a view showing the XRD topography of the sintered body material of Experimental Example 18.

Fig. 9 is a view showing an electron microscopic analyzer (EPMA) image of the sintered body material of Experimental Example 7.

Fig. 10 is a view showing an EPMA image of the sintered body material of Experimental Example 7.

Figure 11 is a perspective view of the laminated structure.

Preferred embodiments of the present invention are described below. 1 is a cross-sectional view of the heater 10 having a shaft, and FIG. 2 is a perspective view of the cylindrical shaft 30.

The heater 10 having a shaft is used to heat a wafer subjected to heat treatment such as plasma vapor deposition (CVD) engineering, and is provided in a vacuum chamber (not shown). The shaft heater 10 includes a wafer supporting heater 20 on which a wafer is placed and in which the impedance heating element 22 is embedded, and a cylindrical shaft 30 joined to the back surface of the wafer supporting heater 20.

The wafer supporting heater 20 is a circular plate element (aluminum nitride element) made of aluminum nitride. An example of the wafer-supporting heater 20 is a sintered body in which a sintering aid is added to the aluminum nitride powder, and the thermal conductivity at room temperature is 150 W/mK or more, and the thermal conductivity at 550 ° C is 80 W/mK or more, and the coefficient of thermal expansion is 5.7 ppm / ° C. The wafer supporting heater 20 is embedded with a molybdenum resistance heating body as the impedance heating body 22. Further, the first hole 24 and the second hole 26 are opened near the center of the back surface of the wafer supporting heater 20. The impedance heating body 22 is wired by the one end 22a of the wafer support heater 20 at a substantially central position, and is routed over the entire surface of the wafer support heater 20, and then reaches the center of the wafer support heater 20. The other end 22b. One end 22a and the other end 22b of the impedance heater 22 are individually exposed from the first hole 24 and the second hole 26 of the wafer support heater 20 to the outside. Further, the wafer supporting heater 20 is also embedded with the plate electrode 23 as a high frequency electrode.

The cylindrical shaft 30 is an element for a semiconductor manufacturing apparatus using a composite material containing aluminum nitride and an aluminum nitride pseudopolymorph as a main constituent phase as a material. The aluminum nitride pseudopolymorph contains ruthenium, aluminum, oxygen, and nitrogen, and has a periodic structure of at least one of a 27R phase and a 21R phase. Alternatively, the aluminum nitride pseudopolymorph is at least 2θ=59.8~60.8° for the X-ray diffraction peak. The room temperature thermal conductivity of the composite material is preferably 50 W/mK or less, more preferably 40 W/mK or less. The thermal conductivity of the operating temperature of the composite material (550 ° C) is preferably 30 W/mK or less, more preferably 25 W/mK or less, still more preferably 20 W/mK or less. The aluminum nitride of the composite material preferably dissolves at least one of lanthanum and oxygen. The mass ratio of the composite material is preferably Al:N:Si:O=59~63:29~34:1~5:2~8, more preferably Al:N:Si:O=59.6~62.7:29.9~33.1 : 1.5~4.5: 2.7~7.1. The thermal expansion coefficient (CTE) of the composite material at 40 to 1000 ° C is preferably 5.5 to 6.0 ppm / ° C, the opening ratio is preferably 0.5% or less, and the bending strength at 4 points is preferably 250 MPa or more. The composite material preferably contains at least one of an oxide of a rare earth metal and an oxynitride of a rare earth metal. In this case, when the total mass of the elements other than the rare earth metal is 100, the mass ratio of the rare earth metal is preferably more than 0 and 3.0 or less. The difference in thermal expansion coefficient between the cylindrical shaft 30 and the wafer supporting heater 10 of 40 to 1000 ° C is preferably 0.3 ppm / ° C or less.

The cylindrical shaft 30 has a step 32 on the way, and is formed as a large diameter portion 34 on the side of the wafer supporting heater 20 and a small diameter portion 36 on the opposite side of the wafer supporting heater 20 with the step 32 as a boundary. Flanges 34a and 36a are formed at the end of the large diameter portion 34 and the end portion of the small diameter portion 36, respectively. Then, the end of the large diameter portion 34 in the cylindrical shaft 30 is joined to the back surface of the wafer supporting heater 20. In the internal space of the cylindrical shaft 30, power supply rods 38 and 38 which are individually joined to one end 22a and the other end 22b of the resistance heating body 22 are provided along the axial direction. The impedance heating element 22 of the wafer supporting heater 20 supplies electric power via the power supply rods 38, 38.

One of the methods of manufacturing the cylindrical shaft 30 will be described below, for example. Here, since the shape of the cylindrical shaft 30 is slightly complicated as shown in Fig. 2, an example in which normal pressure firing is employed is shown. First, it is mixed in such a manner that aluminum nitride is 81 to 95% by mass, alumina is 3 to 13% by mass, and tantalum nitride is 2 to 9% by mass based on the total mass of aluminum nitride, aluminum oxide, and tantalum nitride. And become a blending powder. It is preferable that the aluminum nitride is mixed in an amount of 81.4 to 94.2% by mass, alumina is 3.0 to 12.6% by mass, and tantalum nitride is 2.8 to 8.2% by mass. Next, this blended powder was filled in a mold, and formed into a tubular molded body by cold equal pressure (CIP). The molded body of the shaft obtained in this manner was fired at 1750 to 1850 ° C using a normal pressure firing furnace, whereby a cylindrical shaft 30 was obtained. Further, a rare earth oxide (for example, Y ₂ O ₃ , Yb ₂ O _{3 ,} or the like) may be added as a sintering aid component to the blended powder. The amount of the rare earth oxide added is preferably 3% by mass or less based on the total mass of the blended powder. Further, if necessary, it is processed into a cylindrical shaft having a desired shape.

The cylindrical shaft 30 is joined to the wafer support heater 20 via the bonding layer 40. The bonding of the wafer supporting heater 20 to the cylindrical shaft 30 is performed, for example, as follows. Aluminum nitride powder (particle diameter: 0.8 μm, oxygen content: 4.8% by mass) was used as the aluminum nitride raw material. Then, the amount of the aluminum nitride raw material is 50 to 90% by mass, and the commercially available magnesium fluoride (purity of 99.9% or more) is added in an amount of 10 to 50% by mass to 100% by mass, and is mixed with alumina mash and joined. Material composition. The acrylic resin was dissolved in terpineol to form a 45 mass% solution as a binder, and was added in a mass ratio of 30% with respect to the bonding material composition, and mixed with an alumina mash to obtain a bonding material paste (paste). ). The bonding material paste is applied to at least one of the bonding surface of the wafer supporting heater 20 and the bonding surface of the cylindrical shaft 30 and dried, and the solvent of the bonding material paste is volatilized, thereby making the bonding material composition Fixed to the joint surface. Thereafter, the joint surface of the wafer support heater 20 and the joint surface of the cylindrical shaft 30 were superposed on each other, and held at a junction temperature (maximum temperature) of 1400 ° C for 2 hours in nitrogen gas. At this time, both of them are pressed in the direction of adhesion in a direction perpendicular to the joint surface, whereby the cylindrical shaft 30 is joined to the wafer support heater 20 via the bonding layer 40. The crystal phase of the bonding layer 40 contains AlN, MgAl ₂ O ₄ (spinel), and YOF (rare earth oxyfluoride). It is presumed that the O element contained in MgAl ₂ O ₄ and YOF is derived from an oxygen element in an aluminum nitride raw material or Y ₂ O ₃ added as a sintering aid, and the Y element contained in YOF is derived from a sintering aid. Added Y ₂ O ₃ .

Here, the amount of heat released from the cylindrical shaft 30 of the heater 10 having the shaft when the thermal conductivity of the cylindrical shaft 30 is changed is obtained by simulation. The thermal conductivity at room temperature of the cylindrical shaft 30 was 80 W/mK, and the thermal conductivity at the operating temperature (550 ° C) was 50 W/mK. The thermal conductivity at room temperature of the cylindrical shaft 30 was 40 W/mK, and the thermal conductivity at 550 ° C was 30 W/mK, and the amount of heat generation was reduced to 70% compared with the object to be compared. The thermal conductivity at room temperature of the cylindrical shaft 30 was 40 W/mK, and the thermal conductivity at 550 ° C was 25 W/mK, and the amount of heat generation was reduced to 65% compared with the object to be compared. The thermal conductivity at room temperature of the cylindrical shaft 30 40 W/mK, the thermal conductivity of 550 ° C is 20 W / mK, the heat release is reduced to 60% compared with the comparison object. Since the amount of heat release from the cylindrical shaft 30 is smaller than that of the comparison object, it is possible to prevent heat from being dissipated from the joint portion of the wafer supporting heater 20 and the cylindrical shaft 30, and this portion becomes a cool spot. As a result, the soaking property of the wafer supporting heater 20 is improved as compared with the comparison object.

According to the present embodiment described above, since the thermal conductivity of the cylindrical shaft 30 is low, heat dissipation of the wafer supporting heater 20 as the aluminum nitride-based element can be suppressed to the cylindrical shaft 30. Therefore, the uniformity of the wafer supporting heater 20 can be made sufficiently high. Further, compared with the mullite used in Patent Document 1, the content of Si is small, and the corrosion resistance is also excellent.

Further, the present invention is not limited to the above-described embodiments, and as long as it is within the technical scope of the present invention, various aspects can be implemented.

For example, in the above-described embodiment, the cylindrical shaft 30 joined to the wafer supporting heater 20 is exemplified as an element for manufacturing a semiconductor device of the present invention, but is not particularly limited as long as it is bonded to nitriding. The element for manufacturing a semiconductor device of the aluminum element may be used.

In the above embodiment, the wafer supporting heater 20 and the cylindrical shaft 30 are bonded via the bonding layer 40 including AlN, spinel, and YOF, but are not particularly limited, and for example, brazing material can be used for bonding. Can be joined directly.

[Examples]

I. Experimental Example 1-21

Experimental Examples 5 to 20 correspond to Examples of the present invention, and Experimental Examples 1-4 and 21 correspond to Comparative Examples. Further, the following examples do not impose any limitation on the invention.

Manufacturing conditions

(raw material)

A commercially available high-purity fine particle powder (having an oxygen content of 0.9%, an impurity component content other than oxygen of 0.1% or less, and an average particle diameter of 1.1 μm) was used as the AlN raw material. A commercially available high-purity fine particle powder (purity: 99.99% or more, average particle diameter: 0.5 μm) was used as the Al ₂ O ₃ raw material. As the Si ₃ N ₄ raw material, a commercially available high-purity fine particle powder (having an oxygen content of 1.3%, an impurity component content other than oxygen of 0.1% or less, and an average particle diameter of 0.6 μm) was used. A commercially available high-purity fine particle powder (purity of 99.9% or more and an average particle diameter of 1 μm) was used as the Y ₂ O ₃ raw material.

(blending)

The AlN raw material, the Al ₂ O ₃ raw material, and the Si ₃ N ₄ raw material (including Y ₂ O ₃ as the case may be) are weighed in a ratio of the raw material composition shown in the first table, and a pot made of nylon is used. A 20 mm iron core of nylon round stone was mixed with alcohol as a solvent for 4 hours. After mixing, the slurry was taken out and dried at 110 ° C in a nitrogen stream. Thereafter, a 30-mesh sieve was used to prepare a blended powder.

(forming)

The blended powder is uniaxially pressure-molded at a pressure of 100 kgf/cm ² to produce A cylindrical molded body of 65 mm and a thickness of about 20 mm. Thereafter, cold pressure equalization was performed at a pressure of 2.5 ton/cm ² . Further, instead of the cylindrical shaft, a material used for the cylindrical molded body was produced, and various characteristics were evaluated.

(burning)

The molding body is placed in a BN-made crucible (sintering container), and the firing temperature (maximum temperature) shown in Table 1 and the holding temperature of the firing temperature are set in the environmental baking furnace made of a carbon heater. Perform baking. Further, vacuum was applied from room temperature to 900 ° C, and after reaching 900 ° C, nitrogen gas was introduced and fired at the highest temperature for a predetermined time, and then cooled to 1400 ° C to complete the firing. The pressure of nitrogen is 1.5 atmospheres, and the temperature rises. The cooling rate is 100~300°C/time.

2. Determination of basic characteristics

Various test pieces were prepared about the obtained sintered bodies of the respective experimental examples, and the following basic characteristics were measured. The results are shown in the second table and the third table.

(opening rate and bulk density)

Pure water was used as the medium and determined by the Archimedes method.

(4 point bending strength)

According to JIS-R1601.

(line thermal expansion coefficient)

Using a thermal mechanical analyzer TMA8310, a thermal expansion curve was measured under an argon atmosphere at a temperature of 20 ° C/min to 1000 ° C, and an average linear thermal expansion count (CTE) of 40 to 1000 ° C was calculated. Alumina was used for the standard sample. In the second table and the third table, ΔCTE indicates the difference in CTE between the CTE of the sintered body obtained in each experimental example and the aluminum nitride-based element (herein, the sintered body of Experimental Example 1).

Thermal conductivity (TE)

The specific heat is measured by a laser scanning method by a differential scanning thermal method (DSC), and is calculated by a thermal conductivity (TC) = specific heat × thermal diffusivity × bulk density. Calculated for TC at room temperature and 550 ° C, respectively.

(consistent with the constituent phase)

For the powder obtained by pulverizing the composite material in a mortar and adding a mixed internal standard (Si), the crystal phase was determined by an X-ray diffraction apparatus. The measurement conditions were CuKα, 40 kV, 40 mA, 2θ=5 to 70°, and a sealed tubular X-ray diffraction apparatus (D8 ADVANCE manufactured by Bruker AXS) was used.

(constituting element ratio)

Al, Y: after the sintered body is pulverized, after dissolution, acid decomposition, and solution, Quantitative by chelate titration or high frequency inductively coupled plasma luminescence spectrometry.

Si: The sintered body was pulverized and quantified by a gravimetric method (according to JIS R 1616). Further, in the case where the content is small, the same as Al and Y is measured by a high-frequency inductively coupled plasma luminescence spectrometry.

N: The sintered body was coarsely pulverized and then quantified by inert gas melting-thermal conductivity method.

O: The sintered body is roughly pulverized and then quantified by an inert gas melting-non-dispersive infrared absorption method.

3. Evaluation

(Experimental Example 1)

The sintered material of Experimental Example 1 was a material obtained by adding Y ₂ O ₃ as a sintering aid to AlN, and was composed of AlN, Al ₂ Y ₄ O ₉ (YAM), and YAlO ₃ (YAL). When the blended powder does not contain Al ₂ O ₃ or Si ₃ N ₄ , no pseudopolymorph is formed, and since the solid solution of Si and O to AlN is small, the thermal conductivity is high. The XRD topography of the sintered body material of Experimental Example 1 is shown in Fig. 3. * in the figure is a Si-derived person who is an internal standard for the measurement of a sintered body.

(Experimental Example 2)

The sintered body material of Experimental Example 2 is a material obtained by adding Si ₃ N ₄ and Y ₂ O ₃ to AlN, and is composed of AlN, Y ₂ Si ₃ O ₃ N ₄ and a trace amount of a 27R phase which is a pseudopolymorph. However, since a sufficient amount of pseudopolymorph cannot be formed without adding Al ₂ O _{3 to the} blended powder, the degree of solid solution of Si and O to AlN is also slight, and the decrease in thermal conductivity is insufficient. The XRD topography of the sintered body material of Experimental Example 2 is shown in Fig. 4.

(Experimental Example 3)

The sintered body material of Experimental Example 3 was a material obtained by adding Al ₂ O ₃ to AlN and baked, and was composed of AlN and Al ₅ O ₆ N. However, since Y ₂ O ₃ was not added to the blended powder and the sinterability was poor, it was a material produced by hot pressing (20 MPa). Since Si ₃ N _{4 is} not added to this material and no pseudopolymorph is formed, the solid solution of Si and O in AlN is small, and the decrease in thermal conductivity is insufficient. The XRD topography of the sintered body material of Experimental Example 3 is shown in Fig. 5.

(Experimental Example 4)

The sintered body material of Experimental Example 4 was a material obtained by adding Al ₂ O ₃ , Si ₃ N ₄ and Y ₂ O ₃ to AlN, and was composed of AlN, Al ₅ Y ₃ O ₁₂ (YAG) and 27R phases. The mass% of Si ₃ N ₄ and Al ₂ O ₃ in the blended powder of the present material is low, and the amount of formation of the pseudopolymorph is small, and the solid solution of Si and O of AlN is insufficient, and the decrease in thermal conductivity is considered. Not enough.

(Examples 5 to 20)

The sintered body materials of Examples 5 to 20 contain a pseudopolymorph of at least one of a 27R phase and a 21R phase in addition to AlN which is a constituent phase. That is, a periodic structure having at least one of a 27R phase and a 21R phase. Moreover, 2θ=59.8~60.8° was observed from the X-ray diffraction peak. In Experimental Examples 5, 7 to 9, 11 to 15, and 18 to 20, Y ₂ O ₃ was added to the raw material, and the constituent phase also contained YAG. Further, Experimental Examples ₆ , ₁₀ , ₁₆ , and ₁₇ are materials which are sintered by hot pressing (20 MPa) without adding Y ₂ O ₃ to the raw material. Since the mass ratio of AlN, Al ₂ O ₃ , and Si ₃ N ₄ in the blended powder of Experimental Examples 5 to 20 is appropriate, the mass ratio of Al, Si, N, and O in the obtained sintered body material is also appropriate, and the pseudopolymorph The formation and the solid solution of Si and O in AlN were also appropriate, and the thermal conductivity was sufficiently lowered. Further, compared with the mullite used in Patent Document 1, the content of Si is small, and the corrosion resistance to a halogen gas or the like is also excellent.

As a representative example, the XRD topography of the sintered body materials of Experimental Examples 5, 11, and 18 is shown in Figures 6-8. According to Figures 6-8, all of these contain AlN, 27R phase, and YAG as constituent phases, and Figures 7 and 8 also contain 21R phase. Moreover, 2θ=59.8~60.8° was observed from the X-ray diffraction peak. According to the sequence of experiments 5, 11, and 18, the mass % of AlN in the blended powder becomes low, and the mass % of Al ₂ O ₃ and Si ₃ N ₄ becomes high, and the mass % of O and Si in the sintered body material is also sequentially Becomes high. Observing the XRD morphology of the sintered body material, it is understood that the peak intensity of AlN or the peak intensity of the pseudopolymorph changes with the mass % of AlN in the blended powder or the mass % of O and Si in the sintered body material. That is, from the relationship between the peak intensities of the XRD topography, the AlN of the material of Experimental Example 5 was inferred as the main phase, the proportion of the pseudopolymorph of the material of Experimental Example 11 was increased, and the material of Experimental Example 18 was compared with AlN. The pseudopolymorph becomes the main phase. The thermal conductivity of each of these materials decreases as the ratio of the constituent elements of Si and O becomes higher, thereby estimating the content of the pseudopolymorphous phase and the amount of solid solution of Si and O in AlN, and the thermal conductivity. The lower it is. Further, the materials of Experimental Examples 5 to 20 can control the thermal expansion coefficient at 5.5 to 6.0 ppm/° C., and the difference in thermal expansion coefficient of the high thermal conductivity aluminum nitride material (5.7 ppm/° C.) shown in Experimental Example 1. It is very small below 0.3 ppm/°C. Further, any of them has a bending strength of 250 MPa or more, and is an element that is resistant to a sufficient structure as an element for a semiconductor manufacturing apparatus. That is, such materials are low thermal conductivity materials having a relatively high matching coefficient of thermal expansion coefficient with respect to a high thermal conductivity aluminum nitride material and having sufficient strength.

Fig. 9 is a view showing an EPMA image of the sintered body material of Experimental Example 7. Figure 9 is a color scale showing the concentration, which is shown as black and white for convenience. In fact, the highest concentration is red, and thus the concentration becomes lower in orange, yellow, yellow-green, and light blue. The order of blue, dark blue is color-coded, and the lowest concentration is shown in black. Figure 9(a) shows the overall elemental distribution. Fig. 9(b) shows the distribution of N. The pixels of gray shade are dispersed in the whole by dot drawing, and the pixels of blue and yellow-green are actually dispersed throughout. Figure 9(c) shows the distribution of O. It can be seen that the blackish part is actually dark blue or black and there is AlN. The slightly bright gray columnar part is actually light blue and there is a pseudo polymorph. (27R phase). Columnar The further bright gray in the part is actually yellow-green to yellow, in which red is also punctiform and YAG is present. Fig. 9(d) shows the distribution of Al. Although the whole is bright gray, actually yellow-green, yellow, and red are dispersed throughout, and it is known that Al exists in the whole. The red part is AlN. Figure 9(e) shows the distribution of Si. It can be seen that the black-colored portion is actually dark blue or black and has less Si. The bright gray columnar portion is actually yellow-green to yellow and has pseudo-polymorphs. (27R phase). Figure 9(f) shows the distribution of Y. It can be seen that the blackish portion is actually dark blue or black, and the bright gray dot portion is actually yellow-green (partially red) and YAG is present. It is taught that the 27R phase of the pseudopolymorph in the matrix in which the dark gray portion is AlN coincides with the portion which is formed into a columnar shape, and the portion other than the portion where Y is YAG is dissolved in the 27R phase.

The 9th (c) or 9th (e) figure cannot fully judge whether or not O or Si is dissolved in the AlN matrix. Therefore, the 10th (c') diagram and the 10th (e') diagram are changed so that the concentration range of the color chart becomes a low concentration and can be distinguished. The figure 10(c') shows that the part of the AlN matrix is bright gray, actually blue, yellowish green, yellow, and there is O. It can also be seen from the 10th (e') diagram that the portion of the AlN matrix is bright gray, actually blue, yellowish green, yellow, and Si is present. From these images, it was found that O and Si were dissolved in AlN of the sintered material of Experimental Example 7. It is considered that the thermal conductivity of the AlN portion is lowered by solid solution of O or Si, and the combination of the low grain boundary phase of thermal conductivity equal to 27R is combined to contribute to the low thermal conductivity of the sintered body material of Experimental Example 7. In particular, since it is important to lower the thermal conductivity of the AlN portion, the coefficient of thermal expansion is maintained at the same level as that of AlN. Therefore, it is possible to reduce the amount of introduction of a phase having a low thermal conductivity other than AlN by solid solution.

(Experimental Example 21)

The sintered body material of Experimental Example 21 was further composed of a 21R phase and a 12H phase, in which the mass % of Al ₂ O ₃ and Si ₃ N ₄ of the blended powder was further increased. Since this Experimental Example 21 was not added with Y ₂ O _{3 as a} raw material, it was sintered at a hot press (20 MPa). Since the constituent phase of the present material does not contain AlN, the thermal conductivity is sufficiently low, but the thermal expansion coefficient is increased to 6.1 ppm/° C., and the difference in thermal expansion coefficient from aluminum nitride is 0.4 ppm/° C.

4. Corrosion resistance

A test piece corresponding to Experimental Example 11 of the Example of the present invention, a test piece (test piece made of aluminum nitride) corresponding to Experimental Example 1 of the comparative example, and a test piece made of mullite were prepared. The following test piece was used: A columnar body of 15 mm × 15 mm × 2 mm was prepared, and a test piece of a mirror-like shape was finished by polishing one surface of the 15 mm × 15 mm surface of the columnar body. The test piece made of mullite was cut out from the following sintered body: it was formed into a diameter of 50 mm and a thickness of 20 mm using a commercially available mullite powder (purity of 99.9% or more), and a pressurizing pressure of 200 kgf was used. /cm ² , 1600 ° C, sintered body obtained by sintering in an argon atmosphere for 5 hours. This mullite test piece has a bulk density of 3.15 g/cm ³ and an open cell ratio of 0.01% or less, and is sufficiently densified.

The corrosion resistance test was carried out in the following order. First, a part of the mirror-finished surface of the test piece was covered with an alumina sintered material to expose the residual portion. Then, the test piece used argon gas as a diluent gas and NF ₃ as a halogen gas at a test temperature of 550 ° C. The gas was exposed to a pressure of 0.1 Torr for 5 hours. Then, the step difference between the surface exposed to the halogen gas and the surface not covered with alumina was measured as the etching amount.

As a result, the test piece of Experimental Example 11 and the test piece of Experimental Example 1 had no significant step difference and the etching amount was 0. On the other hand, the test piece made of mullite was found to have a step of 0.2 μm, and corrosion resistance was found to be different. In other words, the corrosion resistance of the halogen gas corresponding to the test piece of the experimental example 1 of the embodiment of the present invention is sufficiently higher than that of the mullite, and it is confirmed that it is equivalent to the aluminum nitride material. The components for semiconductor manufacturing devices have high flexibility.

II. Experimental examples 22~25

In the experimental example 22, the first structure composed of the aluminum nitride sintered body of Experimental Example 1 and the second structure of the sintered body of Experimental Example 11 were individually processed into 50 mm, thickness 10 mm, the paste was applied to one of the structures and dried, laminated to another structure, and stored in a graphite mold at 1430 ° C for 5 hours by hot pressing (load 60 kgf / cm ² ) Further, a laminated structure is obtained in which the paste is composed of aluminum nitride (AlN), magnesium fluoride (MgF ₂ ), and alumina (Al ₂ O ₃ ) at a ratio of 67.3% by mass, 19.0% by mass, and 4.7% by mass. The mixed powder is obtained by mixing with a solvent and an organic binder in an arbitrary ratio. A perspective view of this laminated structure is shown in Fig. 11. In the experimental example 23, the sintered body of the experimental example 18 was used as the second structure, the experimental example 24 used the sintered body of the experimental example 21 as the second structure, and the experimental example 25 used the sintered body of the experimental example 9 as the second structure. The laminated structure was obtained in the same manner as in Experimental Example 22 except for the above.

The laminate structure obtained in Experimental Examples 22 to 25 was visually recognized as having no cracks and was excellent in bonding. However, the laminated structure perpendicular to the joint surface was cut perpendicularly to each of the laminated structures, and the laminated structures of Experimental Examples 22, 23, and 25 were determined to be free of cracks, whereas the laminated structure of Experimental Example 24 was in the first structure. The end of the body is considered to be cracked (please refer to Table 4). Experimental Examples 22, 23, 25 The difference in thermal expansion coefficient (ΔCTE) between the first structure and the second structure of the laminated structure is 0.3 ppm/° C. or less, and it is considered that the difference in thermal expansion coefficient of Experimental Example 24 is as large as 0.4 ppm/° C. Thermal stress is generated at the time of joining, and cracking occurs due to opening of thermal stress during cutting processing. That is, in order to obtain a more stable or highly reliable bonded body, it is desirable that the difference in thermal expansion coefficient between the two structures is 0.3 ppm/° C. or less. Further, Experimental Examples 22, 23, and 25 correspond to the examples of the present invention, and Experimental Example 24 corresponds to Comparative Examples.

The present application is based on the priority of Japanese Patent Application No. 2015-214956, filed on Oct. 30, 2015, and the Japanese Patent Application No. 2016-189843, filed on Sep. The contents are all included in this specification.

10‧‧‧With shaft heater

20‧‧‧ Wafer Support Heater

22‧‧‧ Impedance heating body

22a‧‧‧End

22b‧‧‧The other end

23‧‧‧Table electrode

24‧‧‧1 hole

26‧‧‧2nd hole

30‧‧‧Cylinder shaft

32‧‧ ‧ paragraph difference

34‧‧‧Great Path Department

34a, 36a‧‧ ‧ flange

36‧‧‧Little Trails Department

38‧‧‧Power pole

40‧‧‧ joint layer

Claims (15)

An element for a semiconductor manufacturing apparatus bonded to an aluminum nitride-based element in which a composite material of aluminum nitride and an aluminum nitride pseudopolymorph as a main constituent phase is used as a material, wherein the aluminum nitride pseudopolymorph includes tantalum and aluminum And oxygen and nitrogen, the aluminum nitride pseudopolymorph has a periodic structure of at least one of a 27R phase and a 21R phase, and the thermal conductivity of the composite material at room temperature is 50 W/mK or less. An element for a semiconductor manufacturing apparatus bonded to an aluminum nitride-based element in which a composite material of aluminum nitride and an aluminum nitride pseudopolymorph as a main constituent phase is used as a material, wherein the aluminum nitride pseudopolymorph includes tantalum and aluminum And oxygen and nitrogen, the X-ray diffraction peak of the aluminum nitride pseudopolymorph exhibits at least 2θ=59.8~60.8°, and the thermal conductivity of the composite material is 50 W/mK or less at room temperature. The element for a semiconductor manufacturing apparatus according to the first aspect of the invention, wherein the aluminum nitride of the composite material has at least one element of tantalum and oxygen dissolved therein. The element for a semiconductor manufacturing apparatus according to claim 1 or 2, wherein when the total mass of Al, N, Si, and O is 100, the mass ratio of Al, N, Si, and O of the composite material is Al: N: Si: O = 59 ~ 63: 29 ~ 34: 1 ~ 5: 2 ~ 8. The element for a semiconductor manufacturing apparatus according to claim 1 or 2, wherein the composite material contains at least one of an oxide of a rare earth metal and an oxynitride of a rare earth metal, and the rare earth metal When the total mass of the outer elements is 100, the mass ratio of the rare earth metal is more than 0 and 3.0 or less. The element for a semiconductor manufacturing apparatus according to claim 1 or 2, wherein the composite material has a thermal conductivity of 550 ° C of 30 W/mK or less. The element for a semiconductor manufacturing apparatus according to claim 1 or 2, wherein the composite material has a thermal expansion coefficient of from 40 to 1000 ° C of from 5.5 to 6.0 ppm/°C. The element for a semiconductor manufacturing apparatus according to the first or second aspect of the invention, wherein the composite material has an opening ratio of 0.5% or less. The element for a semiconductor manufacturing apparatus according to the first or second aspect of the invention, wherein the composite material has a 4-point bending strength of 250 MPa or more. In a method for producing a device for a semiconductor manufacturing device, aluminum nitride is 81 to 95% by mass, alumina is 3 to 13% by mass, and tantalum nitride is used as a total mass of aluminum nitride, aluminum oxide, and tantalum nitride. 2 to 9 mass% of the mixture is blended to form a blended powder, and the blended powder is molded to form a molded body, and the molded body is fired at 1750 to 1850 ° C, thereby obtaining the method as described in claim 1 or 2. An element for a semiconductor manufacturing device. The method for producing a device for a semiconductor manufacturing device according to claim 10, wherein a rare earth oxide is added as a sintering aid component to the blended powder. A heater having a shaft, comprising: a shaft for an element for a semiconductor manufacturing apparatus according to claim 1 or 2; and a wafer supporting heater joined to the shaft and using an aluminum nitride-based material Make For materials. The heater having a shaft according to claim 12, wherein a difference in thermal expansion coefficient between the shaft and the wafer supporting heater of 40 to 1000 ° C is 0.3 ppm/° C. or less. The shaft heater according to claim 12, wherein the bonding layer joining the shaft and the wafer supporting heater comprises aluminum nitride, spinel, and rare earth oxyfluoride. The heater having a shaft according to claim 13, wherein the bonding layer joining the shaft and the wafer supporting heater comprises aluminum nitride, spinel, and rare earth oxyfluoride.