TWI579255B - A ceramic material, a laminated body, a member for a semiconductor manufacturing apparatus, and a sputtering ring target member - Google Patents

Description

Ceramic material, laminate, member for semiconductor manufacturing apparatus, and sputter ring target member

The present invention relates to a ceramic material, a laminate, a member for a semiconductor manufacturing apparatus, and a sputtering ring target member.

In a semiconductor manufacturing apparatus used for a dry process or a plasma film at the time of semiconductor manufacturing, a halogen-based plasma such as fluorine or chlorine having high reactivity is used for etching or cleaning. Therefore, a member to be mounted in such a semiconductor manufacturing apparatus is required to have high corrosion resistance, and generally, a highly corrosion-resistant metal or ceramic member such as aluminum or HASTELLOY alloy treated with an aluminum oxide film is used. In particular, electrostatic chucks or heating devices that support fixed silicon wafers are required to have high corrosion resistance and low dust generation, and therefore high corrosion resistant ceramic members such as aluminum nitride, aluminum oxide, and sapphire are used. Since these materials are gradually used as a cause of dusting due to long-term use, materials with higher corrosion resistance are expected. In order to satisfy such a demand, it is considered to use a higher corrosion-resistant magnesium oxide or spinel (MgAl ₂ O ₄ ) or a composite material thereof as a material (for example, Patent Document 1).

Further, due to the miniaturization of the wiring, members supporting the fixed silicon wafer such as an electrostatic chuck or a heater are required to have excellent heat uniformity. The material having a high thermal conductivity is preferably used for the improvement of the soaking property, and examples thereof include aluminum nitride, aluminum oxide, and cerium oxide. Among them, aluminum nitride has excellent thermal conductivity and is excellent in high yield. It is uniform in heat, but its plasma corrosion resistance is known to be low compared to alumina and yttria.

In addition, magnesium oxide can be used as various additives or electronic component applications, phosphor materials, various target materials, raw materials for superconducting film substrates, and magnetic tunnel junction elements (MJT devices). The use of a tunnel barrier, a protective film for a color plasma display (PDP), and a raw material for a crystalline magnesium oxide layer for a PDP has been attracting attention as a material having an extremely wide range of applications. In addition, it can be used as a sputtering ring target, and can be used for the fabrication of a tunnel barrier of an MJT device using a tunnel magnetic resistance effect, a protective film for an electrode of a PDP, and a dielectric. The magnetic resistance effect of the tunnel is in the MTJ element in which the two magnetic layers sandwich a very thin insulator having a thickness of several nm, and the relative directions of magnetization of the two magnetic layers are parallel or anti-parallel. A magnetic head applied to a hard disk or the like by utilizing a change in resistance caused by the magnetization state.

Leading patent documents:

[Patent Literature]

[Patent Document 1] Japanese Patent No. 3559426

However, since magnesium oxide reacts with moisture or carbon dioxide in the atmosphere to form a hydroxide or a carbonate, the surface of the magnesium oxide gradually deteriorates (a problem of moisture resistance). Therefore, when it is applied to a member for a semiconductor manufacturing apparatus, there is a gas generated by decomposition of a hydroxide or a carbonate, or a phenomenon in which a semiconductor element is contaminated by particle formation or dust generation of the magnesium oxide. Applications are not universal.

On the other hand, although spinel has no problem of moisture resistance, it is said that it has high corrosion resistance to halogen plasma compared to alumina, but it cannot be said to be very full. Minute.

Further, in the composite material of magnesium oxide and spinel, when the amount of the magnesium oxide is large, the moisture resistance is a problem, and when the amount is small, the degree of the problem of the moisture resistance is small, but the corrosion resistance is close to that of the spinel. Therefore, the superiority with respect to alumina or the like is small.

In general, as a material having high corrosion resistance to a halogen-based plasma, magnesium oxide, followed by spinel, alumina, aluminum nitride, or the like can be given. Among them, the thermal conductivity of aluminum nitride is excellent overwhelming, and it is the best material for the discovery of soaking heat. Therefore, in order to achieve both corrosion resistance and conductivity, it is preferable to laminate a structure of aluminum nitride and a highly corrosion-resistant material, but since the thermal expansion difference between the aluminum nitride and the high corrosion-resistant material is large, the sintering of both layers is generated. The problem of cracks.

The present invention has been made to solve such a problem, and is intended to provide a ceramic material having a corrosion resistance equivalent to or higher than that of a spinel for a halogen-based plasma. Further, it is one of the objects to provide a ceramic material having corrosion resistance equivalent to that of spinel but having a linear thermal expansion coefficient lower than that of spinel and similar to aluminum nitride having high homogenization.

Further, in recent years, magnetoresistive random access memories (hereinafter referred to as MRAMs) using the above-described MTJ elements have been reviewed. For example, many MRAM devices are equipped with MTJ components, and their respective magnetizations are arranged as an information carrier. They are characterized by non-volatility, high speed, and high write endurance. Therefore, as a memory, the development of the MRAM is superior to the conventional semiconductor. So far, memory with a memory capacity of several to several tens of millions of bits (Mbit) has been tried, but in order to replace, for example, DRAM, a larger capacity of a gigabit (Gbit) level is necessary.

As a tunnel barrier material for MTJ components from the past to the present, generally use single crystal or high purity magnesium oxide, using sputter ring of magnesium oxide It is common for the target to form a tunnel barrier film. However, for greater capacity, since the resistance of the MTJ element is low, a high magnetoresistance ratio is desired in order to obtain a large output signal.

The present invention has been made to solve such a problem, and is intended to provide a sputter ring target having a lower electrical resistance than magnesium oxide. By using this target to fabricate a magnetic tunnel junction element, it is expected that the resistance is lowered.

The present inventors examined the corrosion resistance of a ceramic powder obtained by firing a mixed powder of magnesium oxide and aluminum oxide and aluminum nitride, and found that the magnesium-aluminum having a peak of XRD at a specific position was examined after the corrosion resistance of the ceramic material obtained by firing. The ceramic material of the oxynitride main phase exhibits a very high corrosion resistance, and the present invention has been completed.

That is, the ceramic material of the present invention is a ceramic material mainly composed of magnesium, aluminum, oxygen and nitrogen, wherein a peak of XRD when CuKα rays are used occurs at a magnesium-aluminum oxide of at least 2θ=47 to 50°. Nitride is the main phase.

The laminate of the present invention has a first structure in which the ceramic material is laminated or bonded, and a second structure in which at least one of aluminum nitride, cerium oxide, and aluminum oxide is a main phase. Structured things.

Further, the member for a semiconductor manufacturing apparatus of the present invention is a material formed of such a ceramic material or a laminate.

Further, the sputter ring target member of the present invention is formed of such a ceramic material.

The ceramic material of the present invention has corrosion resistance equal to or higher than that of spinel. Therefore, the member for a semiconductor manufacturing apparatus formed of the ceramic material can withstand long-term use of a halogen-based plasma such as fluorine or chlorine which is highly reactive in the production of a semiconductor, and can reduce the amount of dust generated from the member. Moreover, in the ceramic material of the present invention, the linear thermal expansion coefficient of the material of the spinel can be made equivalent to the corrosion resistance. The spinel is low. Therefore, it is possible to easily obtain a laminate of a material such as aluminum nitride having a high heat build-up or a low coefficient of thermal expansion.

Further, the ceramic material of the present invention has a lower electrical resistance than magnesium oxide. Therefore, when the sputtering ring target member formed of the ceramic material is used as a tunnel barrier of a magnetic tunnel junction element, magnesium, aluminum, oxygen, and nitrogen are contained in the tunnel barrier layer, and magnesium oxide is expected to be obtained. Low resistance magnetic tunneling element. Moreover, there is a possibility of obtaining a magnetic tunnel junction element having a high magnetoresistance ratio.

Fig. 1 is an XRD analysis chart of Example 1.

Figure 2 is an EPMA element control image of Examples 1 and 4.

Figure 3 is an XRD analysis chart of Example 7.

Fig. 4 is an XRD analysis chart of Example 10.

The ceramic material of the present invention is a ceramic material mainly composed of magnesium, aluminum, oxygen and nitrogen, and the peak of XRD when CuKα ray is used appears as a main phase of magnesium-aluminum oxynitride at least at 2θ=47~50°. . Since the corrosion resistance of the magnesium-aluminum oxynitride to the halogen-based plasma is equal to or higher than that of the spinel, the corrosion resistance of the ceramic material of the present invention in which the oxynitride is the main phase is also considered to be high. Further, the magnesium-aluminum oxynitride may be a material having corrosion resistance equivalent to that of spinel but having a lower coefficient of thermal expansion than that of spinel.

The ceramic material of the present invention may contain a crystal phase of a magnesium oxide-aluminum nitride solid solution in which aluminum nitride is solid-dissolved in magnesium oxide as a subphase. Due to this oxygen Since the magnesium-aluminum nitride solid solution has high corrosion resistance, it is also a problem as a secondary phase. The magnesium oxide-aluminum nitride solid solution is a 2θ between the peak of the magnesia cubic crystal and the peak of the aluminum nitride cubic crystal at the peak of the XRD of the (200) plane and the (220) plane when the CuKα ray is used. =42.9~44.8°, 62.3~65.2° is also possible. Moreover, the XRD peak of the (111) plane appears between the peak of the magnesia cubic crystal and the peak of the aluminum nitride cubic crystal. 2θ=36.9 Also between ~39°. Since the peak of the (111) plane and the peak of other crystal phases are difficult to discriminate, only the XRD peak of the (200) plane and the (220) plane may appear in the above range. Similarly, it is difficult to determine the peak of the (200) plane or the (220) plane and the peak of other crystal phases.

In the ceramic material of the present invention, in order to obtain corrosion resistance equivalent to spinel or higher, since the aluminum nitride crystal phase as a secondary phase tends to have low corrosion resistance, the aluminum nitride crystal phase is less. Better, not containing better. Further, since the spinel is more resistant to corrosion than alumina or aluminum nitride crystals, it may contain a small amount. However, since the spinel is less in corrosion resistance than the magnesium-aluminum oxynitride phase of the present invention and the magnesium oxide-aluminum nitride solid solution, it is preferably less. On the other hand, in order to make it equivalent to the spinel corrosion resistance and to have a low coefficient of linear thermal expansion, a small amount of spinel or aluminum nitride crystal phase may be contained.

The ceramic material of the present invention preferably has a magnesium/aluminum molar ratio of 0.20 or more and 2 or less in order to obtain spinel or higher corrosion resistance, and the magnesium/aluminum molar ratio is 0.75 or more and 2 or less. Better. When the amount of the magnesium/aluminum molar ratio is less than 0.2, the amount of formation of any of aluminum nitride, spinel, and alumina increases, and there is a tendency to lose high corrosion resistance. If the magnesium/aluminum molar ratio exceeds 2, the magnesium oxide-aluminum nitride solid solution easily becomes the main phase. On the other hand, to have The corrosion resistance of the spinel is equivalent to that of the spinel, and the coefficient of thermal expansion of the wire is low. The magnesium/aluminum molar ratio in the raw material powder is preferably 0.05 or more and 1.5 or more, and the magnesium/aluminum molar ratio is preferably 0.1 or more and 1 or less.

In the ceramic material of the present invention, the open porosity is preferably 5% or less. Here, the open porosity is a value measured by the Archimedes method using pure water as a medium. If the open porosity is more than 5%, there is a risk that the strength may be lowered or the material itself may be degranulated to cause dusting, and even when the material is processed, the dusting component may be easily accumulated in the pores. Also, the open porosity is preferably as close as possible to zero. Therefore, there is no special lower limit.

The ceramic material of the present invention can be used for a laminate having a structure in which a first structure using the ceramic material and a second structure in which at least one of aluminum nitride, cerium oxide, and aluminum oxide is a main phase is used. . Further, the first structure and the second structure may have a structure after lamination or bonding. As described above, the first structure having high corrosion resistance and the second structure having characteristics different from those of the first structure (for example, heat transferability, mechanical strength, etc.) can improve other characteristics in addition to corrosion resistance. Here, the first structure may be a film, a plate-like body or a layered body formed of the ceramic material. Further, the second structure may be a film, a plate-like body or a layered body in which aluminum nitride, cerium oxide, and aluminum oxide are the main phases. Further, the bonding may be performed in any manner, for example, by sintering bonding or by bonding with an adhesive.

In this case, in the laminate of the present invention, the first structure and the second structure may be joined to each other through the intermediate layer. In this way, by the intermediate layer, for example, peeling of the first structure body and the second structure body due to the difference in the coefficient of thermal expansion can be suppressed. The intermediate layer may be a layer having a property intermediate between the first structure and the second structure. The intermediate layer may be, for example, a main phase and a second structure in which the first structure is mixed. The layer of the main phase of the creation. Further, the intermediate layer may be a component containing a plurality of layers or a plurality of components having different composition ratios. In this way, it can be a material-like property.

Further, in the laminate of the present invention, the linear thermal expansion coefficient difference between the first structural body and the second structural body is 0.3 ppm/K or less, and the first structural body and the second structural body may be directly joined. As described above, since the difference between the linear thermal expansion coefficients of the first structure and the second structure is small, when the two structures are joined at a high temperature (for example, by sintering) or when the use of the laminate is repeated at a high temperature and a low temperature, There is no risk of cracking or peeling.

The ceramic material of the present invention can be used for a member for a semiconductor manufacturing apparatus. As a member for a semiconductor manufacturing apparatus, for example, an electrostatic chuck or a carrier disk used for a semiconductor manufacturing apparatus, a heater, a thin plate, an inner wall material, a monitor window, a microwave introduction window, a microwave coupling antenna, and the like can be given. These are considered to have excellent corrosion resistance to a plasma containing a halogen-containing corrosive gas, and therefore it is suitable to use the ceramic material of the present invention.

In the ceramic material of the present invention, the magnesium-aluminum oxynitride as the main phase has a thermal expansion coefficient of 40 to 1000 ° C of 6 to 7 ppm/k, and the magnesium oxide-aluminum nitride solid solution of the subphase component is changed. (12~14ppm/k), or the ratio of spinel (8~9ppm/k) and aluminum nitride (5~6ppm/k), and the coefficient of linear thermal expansion can be controlled at 5.5~ while maintaining high corrosion resistance. 10ppm/k. However, since spinel or aluminum nitride has lower corrosion resistance than magnesium-aluminum oxynitride or magnesium oxide-aluminum nitride solid solution, it is less preferable. By such adjustment of thermal expansion, alumina, yttria, aluminum nitride, or the like can be used as a thermal expansion of a material used for a member for a semiconductor manufacturing apparatus, or a difference in thermal expansion is small. Thereby, it is also possible to laminate or bond the ceramic material of the present invention with the prior material. In this way, you can only make the table The surface (first structure) is a ceramic material having high corrosion resistance of the present invention, and the substrate of the lower portion (second structure) is a prior material. In particular, such a layer structure and thermal expansion adjustment are effective in integral sintering. Further, by using a material mainly composed of aluminum nitride in the base material of the second structure, high heat conduction can be maintained, and the surface temperature of the highly corrosion-resistant ceramic magnetic material can be kept uniform. Such a configuration is effective particularly in a heater-built semiconductor manufacturing apparatus.

Further, the ceramic magnetic material of the present invention can be used for sputtering a ring target member member. That is, the sputter ring target member of the present invention may be a ceramic material mainly composed of magnesium, aluminum, oxygen and nitrogen, and the XRD peak when using CuKα rays appears at at least 2θ=47~50°. Magnesium-aluminum oxynitride is a material formed by a ceramic material of a main phase. The ceramic material of the present invention is preferably used as a target member of a sputter ring because it has a lower electrical resistance than magnesium oxide. As a sputter ring target member, for example, a tunnel barrier for a magnetic tunnel junction element can also be fabricated. In this case, it is preferable that the ceramic material of the present invention is used for a magnetic tunnel junction element of at least one of a magnetic head of a hard disk and a magnetoresistive random access memory. These are considered to be very suitable for use of the ceramic material of the present invention because it is considered to require a low electrical resistance or a high magnetic reluctance ratio.

The ceramic material of the present invention can be produced by molding and sintering a mixed powder of magnesium oxide and aluminum oxide and aluminum nitride. For example, in order to obtain corrosion resistance equivalent to or higher than that of spinel, magnesium oxide is added in an amount of 15% by mass or more and 66.2% by mass or less, alumina is 63% by mass or less, and aluminum nitride is mixed at 57.7% by mass or less. The powder may be fired after molding. Further, the powder may be formed by calcining the magnesia in an amount of 37% by mass or more and 66.2% by mass or less, alumina in an amount of 63% by mass or less, and aluminum nitride in an amount of 57.7 mass% or less. On the other hand, in order to have corrosion resistance equivalent to that of spinel and to have a linear thermal expansion coefficient and high heat homogenization, magnesium oxide is contained in an amount of 5 mass% or more and 60 mass% or less, and alumina is 60 mass% or less. The powder may be mixed at 90% by mass or less and then fired. Further, the firing temperature is preferably 1750 ° C or higher. If the firing temperature is less than 1750 ° C, the target magnesium-aluminum oxynitride cannot be obtained. Further, the upper limit of the firing temperature is not particularly limited, and may be, for example, 1850 ° C or 1900 ° C. Further, the firing is preferably carried out by hot press firing, and the pressure at the time of hot press firing is preferably 50 to 300 kgf/cm ² . The atmosphere at the time of firing is preferably an atmosphere which does not affect the firing of the oxide raw material, and is preferably, for example, a nitrogen atmosphere, an argon atmosphere, or an inert atmosphere such as a helium atmosphere. The pressure at the time of molding is not particularly limited, and may be appropriately set to a pressure at which the shape can be maintained.

[Examples]

Hereinafter, a preferred application of the present invention will be described. The magnesium oxide raw material, the alumina raw material, and the aluminum nitride raw material are commercially available products having a purity of 99.9% or more and an average particle diameter of 1 μm or less. Here, regarding the aluminum nitride raw material, since the content of oxygen of about 1% by mass is unavoidable, the purity of oxygen is subtracted from the impurity element. Moreover, even if the purity of the magnesium oxide raw material is 99% or more, a ceramic material equivalent to the case where the purity is 99.9% or more can be produced.

Ceramic material

First, a ceramic material containing magnesium, aluminum, oxygen, and nitrogen as a main component is explained (Experimental Examples 1 to 19). Further, Experimental Examples 1 to 3 and 6 to 16 correspond to the examples of the present invention, and Experimental Examples 4, 5 and 17 to 19 correspond to comparative examples.

[Experimental Examples 1~3]

. Blending

The magnesium oxide raw material, the alumina raw material and the aluminum nitride raw material are shown in Table 1. The mass % was weighed, and isopropyl alcohol was used as a solvent. In a bottle made of Nylon, a 5 mm diameter alumina grindstone was used and wet-mixed for 4 hours. After mixing, the suspension was taken out and dried at 110 ° C in a nitrogen gas stream. After that, it passed through a 30 mesh screen to become a blended powder. Further, the blended powder had a magnesium/aluminum molar ratio of 1.2.

. Forming

The blended powder was pressure-molded at a pressure of 200 kgf/cm ^{2 to} prepare a disk-shaped molded body having a thickness of about 35 mm and a disk-shaped molded body of about 10 mm, and was placed in a graphite model for firing.

. Burning

The disk-shaped formed body was fired by hot pressing to obtain a ceramic material. In the hot press baking, the pressure was 200 kgf/cm ² , and the firing was performed at the firing temperature (the highest temperature) shown in Table 1, and the argon atmosphere was obtained until the completion of the firing. The holding time at the firing temperature was 4 hours.

[Experimental Example 4]

A ceramic material was obtained in the same manner as in Experimental Example 1, except that the magnesium oxide raw material and the alumina raw material were weighed in the mass % shown in Table 1.

[Experimental Example 5]

A ceramic material was obtained in the same manner as in Experimental Example 1, except that the firing temperature was set to 1650 °C.

[Experimental Examples 6~12]

The magnesium oxide raw material, the alumina raw material, and the aluminum nitride were weighed in the mass % shown in Table 1, and the firing temperature was set to the temperature shown in Table 1, except that the firing atmosphere was nitrogen gas, and the same as Experimental Example 1. A ceramic material is obtained.

[Evaluation]

Each of the materials obtained in Experimental Examples 1 to 19 was processed into various evaluations. The following evaluation. The results of each evaluation are shown in Table 1. Further, in Experimental Examples 1 to 19, a sample having a diameter of 50 mm was also prepared, and the evaluation results similar to those in Table 1 were also obtained.

(1) Overall density. Open porosity

It is determined by the Archimedes method using pure water as a medium.

(2) Evaluation of crystal phase

The material was pulverized in a mortar and the crystal phase was investigated by an X-ray diffraction device. The measurement conditions were CuKα, 40 kV, 40 mA, 2θ=5 to 70°, and a sealed tubular X-ray diffraction device (D8 ADVANCE manufactured by Bruker AXS) was used.

(3) Etching rate

The surface of each material was ground to a mirror surface, and the corrosion resistance test was performed under the following conditions using an ICP plasma corrosion resistance test apparatus. The etching rate of each material was calculated by dividing the difference between the mask surface and the exposed surface measured by the step difference by the test time.

ICP: 800 W, bias voltage: 450 W, introduction gas: NF ₃ /O ₂ /Ar=75/35/100 sccm, 0.05 Torr (6.67 Pa), exposure time: 10 hours, sample temperature: room temperature.

(4) constituent elements

The EPMA was used to detect and determine the constituent elements and analyze the concentration of each constituent element.

(5) Average linear thermal expansion coefficient (40~1000°C)

It was measured in an argon atmosphere using a thermal dilatometer (manufactured by Bruker. AXS).

(6) bending strength

Determined by the bending strength test according to JIS-R1601,

(7) Volumetric impedance measurement

It was measured in the atmosphere at room temperature (25 ° C) according to the method of JIS-C2141. The shape of the test piece was 50 mm × (0.5 to 1 mm) in diameter, the main electrode was 20 mm in diameter, the protective electrode was 30 mm in inner diameter, 40 mm in outer diameter, and the electrode was 40 mm in diameter, and each electrode was formed of silver. The applied voltage was 2 kV/mm, and the current value was read 1 minute after the voltage application, and the room temperature volume resistivity was calculated from the current value. Further, Experimental Example 7 and Experimental Example 19 (magnesium oxide sintered body) were measured at 600 ° C under vacuum (0.01 Pa or less). The shape of the test piece was 50 mm × (0.5 to 1 mm) in diameter, the main electrode was 20 mm in diameter, the protective electrode was 30 mm in inner diameter, 40 mm in outer diameter, and the electrode was 40 mm in diameter, and each electrode was formed of silver. The applied voltage was 500 V/mm, and the current value was read 1 minute after the voltage application, and the volume resistivity was calculated from the current value. Further, in the volume resistivity of Table 1, "aEb" represents a × 10 ^b , and for example, "1E16" represents 1 × 10 ¹⁶ .

[Evaluation results]

Fig. 1 shows an XRD analysis chart of Experimental Example 1. Further, the XRD analysis charts of Experimental Examples 2 and 3 are almost the same as those of Experimental Example 1, and therefore the illustration thereof is omitted. Further, the crystal phases detected in the experimental examples 1 to 19 are shown in Table 1. As shown in Fig. 1, the XRD analysis chart of the ceramic materials in Experimental Examples 1 to 3 is a peak of a complex number which cannot be determined (in the first figure) and a magnesium oxide which is solid-dissolved in magnesium oxide-aluminum oxide- The peak of the aluminum nitride solid solution (○ in the first figure) is composed. The peak that cannot be set at the same time (□) has a peak of 2θ=47~49° (47~50°) which is inconsistent with any of magnesium oxide, spinel and aluminum nitride, and is presumed to be magnesium-aluminum oxynitride. Further, the peak of these magnesium-aluminum oxynitrides is, for example, as described in Reference 1 (J. Am. Ceram. Soc., 93 [2] 322-325 (2010)) or Reference 2 (JP-2008-115065). The peaks of MgAlON (or magnesium aluminoxide, magnesium aron) are inconsistent. In general. These MgAlONs are known to have a nitrogen component dissolved in a spinel, and are considered to have a crystal structure different from the magnesium-aluminum oxynitride of the present invention.

The XRD peaks at the (111), (200), and (220) planes of the magnesium oxide-aluminum nitride solid solution occur at 2θ between the peak of the magnesia cubic crystal and the peak of the aluminum nitride cubic crystal. =36.9~39°, 42.9~44.8°, 62.3~65.2°. Fig. 2 is a view showing a control image of the EPMA element of Experimental Example 1. 2, it can be confirmed that Experimental Example 1 consists of two phases of magnesium-aluminum oxynitride (x) and magnesium oxide-aluminum nitride solid solution (y) shown in Fig. 1 The main phase. Here, the main phase means a component having a volume ratio of 50% or more, and the subphase means a phase which is equal to the XRD peak other than the main phase. Since the area ratio in the cross-sectional observation is considered to reflect the volume ratio, the main phase is an area having an area of 50% or more in the EPMA element control image, and the sub-phase is a field other than the main phase. From Fig. 2, the area ratio of magnesium-aluminum oxynitride was about 66%, and it was found that magnesium-aluminum oxynitride was the main phase. Further, the x portion is specifically defined as a magnesium-aluminum oxynitride because it is composed of four components of magnesium, aluminum, oxygen, and nitrogen, and the magnesium and nitrogen portions thereof are compared with the spinel stone (z portion) of Experimental Example 4. The concentration is high, the aluminum concentration is the same, and the oxygen concentration is low. That is, the magnesium-aluminum oxynitride is characterized by containing more magnesium than the spinel. The same analysis was carried out for other experimental examples. For example, the area ratio of magnesium-aluminum oxynitride in Experimental Example 10 was about 87%, and it was found that magnesium-aluminum oxynitride was the main phase. Here, as an example, the determination method of the main phase and the subphase is performed by the EPMA element comparison, but other methods may be employed as long as it is a method of recognizing each volume ratio.

Further, the EPMA element control image is divided into red, orange, yellow green, green, cyan, blue, etc. according to the concentration, red is the highest concentration, blue is the lowest concentration, and black is 0. However, since the second drawing is shown in black and white, the following is a description of the original color of the second drawing. In Experimental Example 1, the x portion of magnesium is yellowish green, the y portion is red, the x portion of aluminum is orange, the y portion is cyan, and the x portion of nitrogen is Orange, y is cyan, x is oxygen blue, and y is orange. In Experimental Example 4, the entire (z) portion of the magnesium was green, the entire aluminum was orange, the entire nitrogen was black, and the entire oxygen was red.

Further, in Experimental Example 4, since aluminum nitride was not used, the above-described magnesium-aluminum oxynitride was not produced, and the ceramic material contained spinel (MgAl ₂ O ₄ ) as a main phase. In Experimental Example 5, since the firing temperature was low, the above-described magnesium-aluminum oxynitride was not formed, and the ceramic material contained magnesium oxide as a main phase and spinel and aluminum nitride as a secondary phase. Fig. 3 is an XRD analysis chart of Experimental Example 7, and Fig. 4 is an XRD analysis chart of Experimental Example 10. According to Fig. 3 and Fig. 4, it can be seen that the experimental examples 7 and 10 were all found to have a magnesium-aluminum oxynitride (in the figure □) having a peak of 2θ=47 to 49° (or 47 to 50°) as the main phase. In Experimental Example 7, spinel (Δ in the figure) was detected, and in Experimental Example 11, a magnesium oxide-aluminum nitride solid solution (○ in the figure) was detected as a subphase. Further, in Experimental Examples 6, 8, 9, 11, and 12, the XRD analysis chart was omitted, and the main phase and the sub-phase are shown in Table 1.

Then, the etching rates of the ceramic materials of Experimental Examples 1 to 3 and 6 to 8 were 80% or less of Experimental Example 4, and the etching rates of Experimental Examples 9 to 12 were lower than 90% of Experimental Example 4. The value is known to be a very high corrosion resistance. In Experimental Example 5, since the spinel or aluminum nitride having low corrosion resistance was contained, the etching rate became high. Further, the etching rate of the alumina shown in Experimental Example 18 was higher than that of the ceramic material (spinel) of Experimental Example 4. Further, in the ceramic materials of Experimental Examples 1 to 3 and 6 to 8, the bending strength or the volume resistivity were also sufficiently high.

Moreover, the etching rate at a high temperature was also measured. Here, for the ceramic materials of Experimental Example 2 and Experimental Example 10, the surface of each material was ground to a mirror surface, and corrosion resistance at a high temperature was performed using an ICP plasma corrosion resistance test apparatus under the following conditions. test. Then, the difference between the mask surface and the exposed surface was measured by a step difference meter divided by the test time to calculate the etching rate of each material. As a result, the etching rate of each material was 1/3 times or less of that of aluminum oxide and 1/5 times or less of that of aluminum nitride, and the plasma corrosion resistance at a high temperature was also good as much as the spinel.

ICP: 800 W, bias: none, introduction gas: NF _{3 /} Ar= _300/300 sccm, 0.1 Torr, exposure time: 5 hours, sample temperature: 650°.

In the ceramic materials of Experimental Examples 12 to 16, the etching rate was almost the same as that of the spinel of Experimental Example 4 (212 to 270 nm/h), and the linear thermal expansion coefficient was lower than that of the spinel (5.8 to 6.9 ppm/K). That is, the ceramic materials of the experimental examples 12 to 16 can be said to have the same corrosion resistance as the spinel but have a low coefficient of linear thermal expansion, and can be said to be an electrostatic chuck or a heating device, particularly as a heating device. useful. Further, in Experimental Example 17, the raw material composition was the same as that of Experimental Example 6. However, since the firing temperature was low, the main phase was not a magnesium-aluminum oxynitride but a spinel, and compared with Experimental Example 6. It has low corrosion resistance and high linear thermal expansion coefficient. Further, the ceramic materials of Experimental Examples 12 to 16 have a sufficiently high value in bending strength or volume resistivity.

Further, the volume resistivities at 600 ° C of Experimental Example 7 and Experimental Example 19 were 5 × 10 ⁸ Ωcm and 2 × 10 ¹² Ωcm, respectively, and it was found that the XRD peak appeared at least at 2θ = 47 to 49 ° (or 47 to 50 °). The magnesium-aluminum oxynitride-based ceramic material has a low electrical resistance compared to magnesium oxide.

From the above, the ceramic materials produced in Experimental Examples 1 to 3 and 6 to 16 were also predicted to have lower electrical resistance than magnesium oxide. Therefore, the material is used as a sputter ring target, for example, in the case of a magnetic tunnel junction element such as a magnetic head and a magnetoresistive random access memory, the characteristics of the resistance and the magnetic group ratio can be predicted.

2. Lamination sintering

Next, a description will be given of a laminate of the first structure and the second structure in which the ceramic material is used for the laminated sintering (Experimental Examples 20 to 26). Further, Experimental Examples 20 to 24 correspond to the examples of the present invention. Experimental examples 25 and 26 correspond to comparative examples.

[Experimental Examples 20, 21]

In the ceramic materials of Experimental Examples 4 and 6 to 12, the average linear thermal expansion coefficient at 40 to 1000 ° C was 7 to 9 ppm/K. In Experimental Examples 20 and 21, as shown in Table 2, the ceramic material of Experimental Example 10 was used as the first structure, and aluminum nitride was used as the second structure, and the first and second structures were laminated. The sample was formed into a sample having a diameter of 50 mm for lamination sintering. In the aluminum nitride, yttria is used as a sintering aid and an additional 5 mass% of the material is added (that is, it is added at a ratio of 5 parts by mass of cerium oxide to 100 parts by mass of aluminum nitride, It is called aluminum nitride [1]), or added with 50% by mass of material (that is, it is added at a ratio of 50 parts by mass of cerium oxide to 100 parts by mass of aluminum nitride, called aluminum nitride [2] ]). The aluminum nitride and cerium oxide raw materials are commercially available products having a purity of 99.9% or more and an average particle diameter of 1 μm or less. Here, regarding the aluminum nitride raw material, since the content of oxygen of about 1% by mass is unavoidable, the purity of oxygen is subtracted from the impurity element. Further, since the aluminum alloy [1] is 5.7 ppm/K and the aluminum nitride [2] is 6.2 ppm/K at an average linear thermal expansion coefficient of 40 to 1000 ° C, the first structure and the second structure are There is a difference in thermal expansion between them. Therefore, an intermediate layer in which aluminum nitride [1], aluminum nitride [2], and the raw material of Experimental Example 10 were mixed was provided between the first structure and the second structure. By this intermediate layer, the difference in thermal expansion can be moderated. In the intermediate layer, the experimental example 20 using aluminum nitride [1] was a three-layer mixture in which the mass ratio was 25:75, 50:50, and 75:25, and the mass of the experimental example 21 using aluminum nitride [2] was used for the mass. Than 40:60, 60:40 Mix 2 layers. Hereinafter, each project such as blending, forming, and baking will be described in detail.

. Blending

The raw material of the first structure was a blended powder prepared in the same manner as in the above Experimental Example 10. The raw material of the second structure is mainly composed of aluminum nitride, and is blended as follows. In the aluminum nitride [1] of the second structure, first, the aluminum nitride powder and the cerium oxide powder are weighed at a ratio of 100% by mass to 5.0% by mass, and isopropyl alcohol is used as a solvent in the bottle of Nylon. , using a nylon-resistant grindstone, wet mixing for 4 hours. After mixing, the suspension was taken out and dried at 110 ° C in a nitrogen gas stream. Thereafter, it passed through a 30 mesh screen to become a blended powder. Further, the obtained blended powder was heat-treated at 450 ° C in an air atmosphere for 5 hours or more, and the carbon component mixed in the wet mixing was burned and removed. The intermediate layer of the laminate using aluminum nitride [1] was blended as follows. First, the blended powder of Experimental Example 10 and the above aluminum nitride strip powder were at a mass ratio of 75:25 (intermediate layer 1), 50:50 (intermediate layer 2), and 25:75 (intermediate layer 3). Weigh the amount, use isopropanol as the solvent, use Nylon grindstone in the bottle of Nylon, and mix it in wet for 4 hours. After mixing, the suspension was taken out and dried at 110 ° C in a nitrogen gas stream. After that, it passed through a 30 mesh screen to become a blended powder. In the aluminum nitride [2] of the second structure, the aluminum nitride powder and the cerium oxide powder are weighed at a ratio of 100% by mass to 50% by mass, and the other is blended in the same manner as the aluminum nitride [1]. . Further, an intermediate layer of a laminate of aluminum nitride [2] was used, and the blended powder of Experimental Example 10 and the above-mentioned aluminum nitride were mixed at a mass ratio of 60:40 (intermediate layer 1), 40:60 (middle). The ratio of layer 2) is weighed, and the others are blended in the same manner as in the case of aluminum nitride [1].

. Forming

First, the aluminum nitride blended powder of the raw material of the second structure was filled in a mold having a diameter of 50 mm, and subjected to one-axis press molding at a pressure of 200 kgf/cm ² . The aluminum nitride formed body was not released from the mold, and the blended powder of the intermediate layer was sequentially filled in the order of the aluminum nitride ratio in the upper portion thereof, and press-molded at 200 kgf/cm ² . The laminate using aluminum nitride [1] is composed of 10 mm of the aluminum nitride layer of the second structure, 1 mm × 3 layers of the intermediate layer, and 10 mm of the layer 10 of the experimental example 10 of the first structure. 23 mm disc shaped body. Further, the laminate using aluminum nitride [2] is formed by 10 mm of the aluminum nitride layer of the second structure, 1 mm × 2 layers of the intermediate layer, and 10 mm of the layer 10 of the experimental example 10 of the first structure. In the case of a disk-shaped molded body of 22 mm, these stacked disk-shaped molded bodies were housed in a graphite model for firing.

. Burning

The disk-shaped descending body accommodated in the graphite model for firing is fired by hot pressing to obtain an integrally fired ceramic material. In the hot press baking, the pressure was 200 kgf/cm ² , and the mixture was fired at a firing temperature of 1800 ° C until the end of the firing. The holding time at the firing temperature was 4 hours. Further, in Experimental Examples 20 and 21, firing at a firing temperature of 1,750 ° C (Experimental Examples 20-1 and 21-1) was also carried out.

The sintered body obtained by the above production method was a laminate of aluminum nitride [1] (Experimental Examples 20 and 20-1) and a laminate using aluminum nitride [2] (Experimental Example) 21, 21-1) is the same as the sintered body in which the upper part is a high-corrosion-resistant magnesium-aluminum oxynitride, and the lower part of the sintered body is a high-heat-conducting aluminum nitride, and an intermediate layer is disposed therebetween. In the intermediate layer, the content of the aluminum nitride is increased as the first structure is close to the second structure, and the ratio is inclined. In these sintered bodies, there are no cracks, cracks, and the like between the layers. This is because the heat in the firing can be avoided by providing an intermediate layer between the first structure and the second structure. force. Further, by controlling the thermal expansion coefficient of the aluminum nitride of the substrate, the thermal stress generated between the substrate and the magnesium-aluminum oxynitride can be made small, and the intermediate layer can be made thin. Such a sintered body is, for example, suitably used as a member for a semiconductor manufacturing apparatus such as an electrostatic chuck or a carrier disk, a heater, a thin plate, an inner wall material, a monitor window, a microwave introduction window, and a microwave coupling antenna.

[Examples 22 to 24]

In Example 22, as shown in Table 2, the ceramic material of Experimental Example 6 was used as the first structure, and alumina was used as the second structure. The laminate was sintered in a nitrogen atmosphere without an intermediate layer, and the same as the examples. 20 to get a laminate. In Experimental Example 23, as shown in Table 2, the ceramic material of Experimental Example 6 was used as the first structure, and cerium oxide was used as the second structure, and the layer was sintered in a nitrogen atmosphere except for the absence of the intermediate layer. 20 to get a laminate. In Example 24, as shown in Table 2, the ceramic material of Experimental Example 13 was the first structure, and aluminum nitride (aluminum nitride [1]) was used as the second structure, except for the absence of the intermediate layer in the nitrogen atmosphere. A laminate was obtained in the same manner as in Example 20 except for lamination sintering. In Experimental Examples 22 to 24, cracks and cracks were not observed between the layers. Further, in Examples 22 to 24, since the difference in linear thermal expansion coefficient between the first structure and the second structure is as small as 0.3 ppm/K or less, the occurrence of cracks, cracks, and the like can be prevented without the intermediate layer. These laminates, similarly to Experimental Examples 20 and 21, are presumably suitable for semiconductor manufacturing such as electrostatic chucks or carrier disks, heaters, sheets, inner wall materials, monitoring windows, microwave introduction windows, and microwave combining antennas. The device is used for components. Further, even in Experimental Examples 22 to 24, the intermediate layer may be provided as in Experimental Examples 20, 20-1, and 21-1.

[Experimental Examples 25, 26]

In Experimental Example 25, as shown in Table 2, alumina was used as the first structure, and nitrided. Aluminum (aluminum nitride [1]) was a second structure, and a laminate was obtained in the same manner as in Experimental Example 20 except that the layer was sintered in a nitrogen atmosphere. In Experimental Example 26, as shown in Table 2, spinel was used as the first structure, and aluminum nitride (aluminum nitride [1]) was used as the second structure, except that the layer was sintered in a nitrogen atmosphere. In Example 20, a laminate was obtained. In any of Experimental Examples 25 and 26, cracks occurred between the layers. This is considered to be because the difference in linear thermal expansion coefficient between the first structural body and the second structural body is excessively large. As a result, although the intermediate layer is provided, the crack due to the difference in thermal expansion cannot be completely prevented.

Japanese Patent Application No. 2010-239000, filed on October 25, 2010, and Japanese Patent Application No. 2011-135312, filed on Jun. 17, 2011, and on August 19, 2011 The division of the application (Application No.: 100136715) on the basis of the priority claim of the Taiwan Patent No. 100130886, the entire contents of which is incorporated herein by reference.

[Industrial Availability]

The ceramic material of the present invention can be used for a member for a semiconductor manufacturing apparatus such as an electrostatic chuck or a carrier disk, a heater, a thin plate, an inner wall material, a monitor window, a microwave introduction window, and a microwave coupling antenna. Alternatively, the ceramic material of the present invention can be used for a sputter ring target member for the production of a magnetic tunnel junction member such as a magnetic head of a hard disk and a magnetoresistive random access memory.

Claims (16)

A ceramic material mainly composed of magnesium, aluminum, oxygen and nitrogen, wherein a peak of XRD when CuKα ray is used occurs in a magnesium-aluminum oxynitride main phase of at least 2θ=47~50°, with a spinel The crystal phase of the stone (MgAl ₂ O ₄ ) and the crystal phase of the aluminum nitride (AlN) are the subphases. The ceramic material of claim 1, wherein the 2θ is 47 to 49°. The ceramic material according to claim 1 or 2, wherein the crystal phase of the magnesium oxide-aluminum nitride solid solution in which the aluminum nitride is solid-solved in the magnesium oxide is a subphase. The ceramic material according to claim 3, wherein the magnesium oxide-aluminum nitride solid solution exhibits a peak of XRD in the (200) plane and the (220) plane when CuKα ray is used. Between 2θ=42.9~44.8° and 62.3~65.2° between the peak of the cubic crystal of aluminum nitride. The ceramic material of claim 4, wherein the magnesium oxide-aluminum nitride solid solution exhibits a peak of the (111) plane XRD peak at the peak of the magnesia cubic crystal and the aluminum nitride when CuKα ray is used. The peak between the peaks of the cubic crystal is between 26.9 and 39°. The ceramic material according to claim 1 or 2, wherein the magnesium source in the starting material is MgO. The ceramic material according to claim 1 or 2, wherein the starting materials are MgO, Al ₂ O ₃ and AlN. The ceramic material according to claim 1 or 2, which is obtained by molding a mixed powder of a starting material and then baking it by hot pressing. For example, the ceramic material of claim 1 or 2 has an open porosity. 0.12% or less. A laminate comprising: a first structure in which a ceramic material according to any one of claims 1 to 9 is laminated or joined; and at least one of aluminum nitride, cerium oxide, and aluminum oxide is used The structure of the second structure of the main phase. The laminate according to claim 10, wherein the first structure and the second structure are joined by an intermediate layer. The laminate according to claim 10, wherein a difference in linear thermal expansion coefficient between the first structural body and the second structural body is 0.3 ppm/K or less, and the first structural body directly joins the second structural system . A member for a semiconductor manufacturing apparatus, which is formed of a ceramic material according to any one of claims 1 to 9. A sputter ring target member formed of the ceramic material of any one of claims 1 to 9. A sputter ring target member according to claim 14 of the patent application, wherein the sputter ring target member is used for making a tunnel barrier of a magnetic tunnel joint element. The sputter ring target member of claim 15, wherein the magnetic tunnel junction element is used for at least one of a hard disk head and a magnetoresistive random access memory.