JP2001223261A - Electrostatic chuck and electrostatic attraction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic chuck and an electrostatic adsorption device in which there is no warping, cracking nor peeling even if the temperature varies due to heating or cooling. SOLUTION: In this electrostatic chuck, a composite material which contains cuprous oxide (Cu2O) by 20-80 vol.% and copper (Cu) and inevitable impurities in the remainder, and whose thermal expansion coefficient from room temperature to 300 deg.C is 5×10-6-14-×10-6/ deg.C and heat conductivity is 30-325 W/m.K, is used for an electrode plate 12, a stress relaxation layer or a base plate 14. As a result difference in thermal expansion coefficient between an insulation layer 11 and the electrode plate 12 or between the insulation layer and the base plate is made small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching apparatus and a CVD apparatus for forming a film on a semiconductor substrate such as a semiconductor wafer, and more particularly to an electrostatic chuck and an electrostatic suction apparatus for holding a semiconductor substrate such as a semiconductor wafer by suction. .

[0002]

2. Description of the Related Art Conventionally, in a semiconductor manufacturing process, a plasma CVD (Chemical Vapor Depo) using a reactive plasma has been used to process a semiconductor substrate such as a semiconductor ware.
sition) apparatus, plasma etching apparatus and the like are used. In these plasma processing apparatuses, an electrostatic suction apparatus is widely used. As a first prior art, an adsorption chuck having an electrostatic chuck formed by directly or indirectly spraying an insulating layer such as alumina on the surface of an electrode plate for a low temperature, and a base plate having the electrostatic chuck fixed and having a cooling mechanism are provided. An apparatus is known, and aluminum is usually used as an electrode and a base plate.

[0003] On the other hand, in a second prior art, for example, for high temperature use, an electrostatic chuck is provided on a ceramic substrate by W, M
An aluminum base plate having a cooling or heating mechanism is known, including a film-shaped electrode layer made of o and the like, an insulating layer formed thereon, an electrode layer incorporated inside an insulating substrate, and the like. They are joined by brazing or the like.

[0004]

In the above-mentioned prior art, the electrostatic chuck has a thermal cycle in which the temperature rises and falls due to heat input through a semiconductor wafer during plasma processing and cooling by a circulator for suppressing overheating of the wafer. Receive. Then, due to the difference in the thermal expansion coefficient between the insulating layer and the electrode, thermal stress of repeated tension or compression is generated on the bonding surface, and there is a problem that the bonding surface is peeled off or the insulating layer is broken.

In order to solve this problem, in the first prior art, the electrode material is made of a thermal expansion coefficient of 7 × 1 of alumina of the insulating layer.
It is necessary to use expensive materials such as W and Mo close to 0 ⁻⁶ / ° C., and there is a disadvantage that the electrodes become very expensive.
In the second prior art, a film-like electrode layer made of W, Mo, or the like is formed, and the reliability of the insulating layer is high. The problem of thermal stress similar to that described in the first prior art is pointed out due to the fact that the heat transfer is inhibited and the difference in the thermal expansion coefficient between the electrostatic chuck and the base plate.

On the other hand, in Japanese Patent Application Laid-Open No. 10-41377, in order to prevent generation of thermal stress due to a difference in thermal expansion between the electrostatic chuck and a base plate made of aluminum or an aluminum alloy, the electrostatic chuck and the base are interposed between the electrostatic chuck and the base. A method of providing a composite material composed of aluminum and alumina, aluminum nitride, or silicon carbide in the stress relaxation layer has been proposed, but disadvantageously, the composite material is expensive and difficult to process.

On the other hand, in the plasma processing, the semiconductor substrate is heated by being irradiated with the plasma particles, so that the temperature rises and adversely affects the quality of the processed film. Therefore, in order to suppress a rise in the temperature of the semiconductor substrate and keep it at a constant temperature, a means for providing a cooling and heating device on the electrode plate or the base plate is usually adopted. However, when aluminum is used for the electrode plate or the base plate, the thermal conductivity of the material is not sufficient, and it is difficult to accurately control the temperature of the semiconductor substrate such as a wafer. Materials having both expandability and high thermal conductivity have been demanded.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent an insulating layer from peeling, warping, and cracking and to efficiently cool or heat an article to be treated even when there is a temperature change due to heating and cooling. An object of the present invention is to provide a chuck and an electrostatic chuck.

[0009]

According to the present invention, there is provided an electrode plate provided with an insulating layer on an upper surface on which an article to be processed such as a semiconductor substrate is electrostatically attracted and mounted, and a cooling or heating structure for holding the electrode plate and for cooling. An electrostatic chuck comprising: a base plate having the electrode plate or the electrode plate and the base plate are made of a composite material containing copper (Cu) and cuprous oxide (Cu ₂ O). I do.

According to the present invention, in the above-mentioned electrostatic chuck,
The electrode plate and the base plate are composed of a composite material having copper (Cu) and cuprous oxide (Cu ₂ O), and the electrode plate is from a bonding surface side with the insulating layer to the base plate side. (Cu) so that the coefficient of thermal expansion gradually increases toward
Characterized by a composite material in which the mixing ratio of cuprous oxide (Cu ₂ O) is reduced.

The present invention provides the above-mentioned electrostatic chuck,
A stress relaxation layer for adjusting a difference in thermal expansion between the electrostatic chuck and the base plate is provided, and the relaxation layer and the base plate are made of copper (Cu) and cuprous oxide (Cu ₂ O). An electrostatic attraction device characterized by being composed of a composite material.

The present invention provides the above-mentioned electrostatic chuck,
A stress relaxation layer is provided between the chuck portion and the base plate for adjusting a difference in thermal expansion between the chuck portion and the base plate, and the relaxation layer and the base plate include copper (Cu) and cuprous oxide (Cu ₂ O). The first copper oxide (Cu) with respect to copper (Cu) is composed of a composite material, and the relaxation layer gradually increases in coefficient of thermal expansion from the bonding surface side with the insulating layer toward the base plate side. It is characterized by comprising a composite material in which the mixing ratio of ₂ O) is reduced.

[0013] The composite material of the present invention comprises copper ( _II) oxide (Cu ₂
O) in an amount of 20 to 80% by volume, the balance being composed of copper (Cu) and unavoidable impurities, having a structure in which the Cu ₂ O phase and Cu phase are dispersed, and having a thermal expansion coefficient of 5 × from room temperature to 300 ° C. 10 ^{−6 to} 14 × 10 ⁻⁶ / ° C. and thermal conductivity of 30
It is preferably ｍ325 W / m · k.

The composite of the present invention is produced by a melting method and a powder metallurgy method. A preferred production method is to prepare a pre-formed body by press-molding a mixed powder containing preferably cuprous oxide (Cu ₂ O) in an amount of 20 to 80% by volume and a balance of copper (Cu) and unavoidable impurities. Thereafter, the preformed body is sintered at a temperature of preferably 800 to 1050 ° C. in an argon gas atmosphere.

The composite material according to the present invention uses Cu, Al, and Ti having high electrical conductivity as a metal, and Cu is most excellent in that it has high thermal conductivity. Also, the particles constituting the composite material are not compounds such as conventional SiC and Al ₂ O ₃ having extremely different hardnesses from the base metal.
It is a relatively soft particle, stable after sintering, and preferably has an average coefficient of thermal expansion in the range of 20 to 150 ° C. of 5.0 × 10 ⁻⁶ / ° C.
It is more preferably at most 3.5 × 10 ⁻⁶ / ° C. and the Vickers hardness is at most 300. By using soft particles as described above, high plastic workability by hot and cold after sintering can be obtained. Copper oxide (Cu ₂ O), tin oxide, lead oxide, nickel oxide and the like can be considered as composite particles. However, copper oxide (Cu ₂ O), which has the smallest coefficient of thermal expansion and is soft, is particularly preferable.

Further, the composite material of the present invention is made of SiC, Al ₂
Hard ceramic particles having a Vickers hardness of 1000 or more and a mean particle size of 3 μm or less such as O ₃ and SiO ₂
It is preferable that the content is not more than 10% by volume to strengthen the steel.

In the present invention, the composite material is made of a Cu—Cu ₂ O alloy having low thermal expansion and high thermal conductivity, and is applied to an electrode material and a base plate as an example, and to a stress relaxation layer and a base plate as another example. The difference in the coefficient of thermal expansion between the members in the above example can be reduced, and problems such as warpage or cracking of the electrostatic chuck or peeling of the joint surface due to thermal stress can be prevented. Further, since the electrode plate, the base plate or the stress relaxation layer has high thermal conductivity, the temperature control of the semiconductor substrate is easy.

That is, the composite material is made of cuprous oxide (Cu ₂
O 2) in an amount of 20 to 80% by volume, with the balance being copper (Cu) and inevitable impurities, having a coefficient of thermal expansion from room temperature to 300 ° C. of 5 × 10 ^{−6 to} 14 × 10 ⁻⁶ / ° C. and thermal conductivity Can be arbitrarily set in the range of 30 to 325 W / m · k, so that the thermal expansion coefficients of the insulating layer or the base material to be joined can be easily adjusted.

The composite material according to the present invention is preferably made of the following sintered alloy or a plastically worked material obtained by hot or cold forging or rolling.

(1) Copper and copper oxide particles having a smaller coefficient of thermal expansion than copper, wherein the number of copper oxide particles alone is 100 or less in a 100 μm square cross section, and The particles are dispersed as a mass of a complex shape connected to each other.

(2) Copper and copper oxide particles having a smaller coefficient of thermal expansion than copper, the particles having a Vickers hardness of 30
0 or less.

(3) Increasing the average coefficient of thermal expansion at 20 to 150 ° C. per 1 W / m · k of thermal conductivity at 20 ° C. comprising copper and copper oxide particles having a smaller coefficient of thermal expansion than copper. Rate 0.02
5 to 0.035 ppm / ° C.

(4) Copper and copper oxide particles having a smaller coefficient of thermal expansion than copper, wherein the compound particles are connected to each other and dispersed as a lump, and the lump is oriented in a direction elongated by plastic working. Extending.

(5) Copper and copper oxide particles are provided, and the copper oxide particles are dispersed in the form of a complex shape in which 95% or more of the whole particles in terms of cross-sectional area are connected to each other.

Further, the composite material according to the present invention is preferably made of the following cast alloy or a plastically worked material obtained by hot or cold forging or rolling.

(1) Copper and preferably copper oxide having a smaller coefficient of thermal expansion than copper, and most of the copper oxide is preferably formed in the form of particles having a particle size of 50 μm or less and dendrites.

It is preferable that the copper oxide is formed in a dendrite shape in which a bar-shaped trunk is formed with particulate branches.

(2) It has copper and copper oxide, and the copper oxide is mostly formed in a granular form and a dendritic form having a particle size of 5 to 50 μm or less, and 1 to 10% of the whole copper oxide has a particle size. Fine particles of 1 μm or less are formed.

(3) It has copper and copper oxide, and has a coefficient of thermal expansion or thermal conductivity that is larger in a solidification direction than in a direction horizontal to that direction.

(4) Particularly preferred is a composite material containing copper and copper oxide.

(5) It has copper and rod-shaped copper oxide having a diameter of 5 to 30 μm. Preferably, the copper oxide has a cross-sectional area ratio of 90% or more with respect to the whole of 5 to 30 μm in diameter.
Is a bar shape.

(6) It has copper and copper oxide and is plastically processed.

(7) Copper and copper oxide and unavoidable impurities. The copper oxide forms a dendrite at 10 to 55% by volume, and has a linear expansion coefficient of 5 × 10 ⁻⁶ from room temperature to 300 ° C.
~ 17 × 10 ^-6 / ° C and room temperature thermal conductivity of 100-38
It is 0 W / mk and has anisotropy.

(8) Copper, copper oxide, preferably copper oxide (Cu ₂ O) and unavoidable impurities. The copper oxide preferably has 10 to 55% by volume, and has a rod shape oriented in one direction. Has a linear expansion coefficient of 5 × 10 from room temperature to 300 ° C.
^{-6 to} 17 × 10 ^-6 / ° C. and room temperature thermal conductivity of 100 to 3
80 W / m · k, and the thermal conductivity in the orientation direction is higher than the thermal conductivity in the direction perpendicular to the orientation direction, preferably the difference is 5 to 100 W / m · k.

(9) In a method for producing a composite material having copper and copper oxide, a step of casting after melting copper or copper and copper oxide in an atmosphere having an oxygen partial pressure of 10 ⁻² Pa to 10 ³ Pa. And a step of performing a heat treatment at 800 ° C. to 1050 ° C. and a step of performing plastic working cold or hot.

[0036]

(Embodiment 1) FIG. 1 shows a sectional view of an electrostatic chuck according to the present invention. The electrostatic chuck includes a base plate 14 provided with cooling or heating holes 13, an electrode plate 12 mounted on the base plate 14, and an insulating layer 11 made of ceramics such as alumina or aluminum nitride. Is supplied with power from the outside.

The electrode plate 12 and the base plate 14 contain 20 to 80% by volume of cuprous oxide (Cu ₂ O), and the balance is copper (C).
u) and unavoidable impurities, and composed of a copper composite material having a thermal expansion coefficient from room temperature to 300 ° C. of 5 × 10 ^{−6 to} 14 × 10 ⁻⁶ / ° C. and a thermal conductivity of 30 to 325 W / mk. Have been. Since the coefficient of thermal expansion of the copper composite material can be arbitrarily selected by adjusting the amount of Cu ₂ O, the insulating layer 1
It is possible to reduce the difference between the thermal expansion coefficients of the base plate 1 and the electrode plate 12 and between the chuck portion 15 and the base plate 14, thereby preventing the chuck portion 15 from being warped or cracking or peeling which may cause foreign matter.

The insulating layer 11 is formed by a method such as thermal spraying or vapor deposition, and the chuck portion 15 and the base plate 14 are joined by mechanical fastening or brazing. Hereinafter, a specific method for producing the copper composite material according to the present invention will be described.

(A) As raw material powder, electrolytic Cu powder having a particle size of 75 μm or less and Cu ₂ O powder having a purity of 3N and a particle size of 1 to ₂ μm were used. Cu powder and Cu ₂ O powder were mixed at a ratio shown in Table 2 to 140
After mixing 0 g, the mixture was mixed in a dry pot mill containing steel balls for 10 hours or more. 150 mixed powder
mm, and 400 to 1 depending on the Cu ₂ O content.
Cold pressed at a pressure of 000 kg / cm ² 150 mm in diameter
A preform having a height of 17 to 19 mm was obtained. Thereafter, the preform was sintered in an argon gas atmosphere and subjected to chemical analysis, structure observation, measurement of thermal expansion coefficient, thermal conductivity, and measurement of Vickers hardness. The sintering temperature was varied between 900 ° C. and 1000 ° C. in accordance with the content of Cu ₂ O, and kept at each temperature for 3 hours. The coefficient of thermal expansion was measured in a temperature range from room temperature to 300 ° C. using a TMA (Thermal Mechanical Analysis) device, and the thermal conductivity was measured by a laser flash method. The results are shown in Table 1.

As a result of chemical analysis, the composition of the sintered body was consistent with the composition. Table 1 shows the thermal expansion coefficient and thermal conductivity.
As is clear, it was found that by adjusting the composition ratio of Cu and Cu ₂ O, the composition varied over a wide range, and it was possible to control the thermal characteristics required for the heat sink.

[0041]

[Table 1]

On the other hand, as is clear from the microstructure, C
Although u ₂ O agglomerates in the mixing step and grows enlarged in the sintering step, the particle size is 50 μm or less, and the Cu phase and Cu
_It has a dense structure in which the 2O phase is uniformly dispersed.

As shown in the figure, it is apparent that the Cu ₂ O particles are dispersed as irregularly shaped masses in which 99% or more of the entire cross-sectional area ratio is continuous.

As a result of the hardness measurement, the Cu phase was Hv 75-8.
0, Cu ₂ O had a hardness of Hv 210 to 230. In addition, as a result of evaluating the machinability by lathe and drill processing,
It was found that the workability was very good, and that the shape was easily imparted.

In the present embodiment, cuprous oxide (Cu ₂ O) was used as a raw material powder. However, even when copper dioxide (CuO) was used, it was changed to Cu ₂ O by sintering in the air. The composite material has Cu ₂ O dispersed therein.

(B) Copper and Cu ₂ O powder having a purity of 2N are shown in Table 2.
The linear expansion coefficient, the thermal conductivity, and the hardness were measured for a composite material which was cast after dissolving the raw materials prepared in the ratios shown in Table 1 in the air. The coefficient of thermal expansion was measured in a temperature range from room temperature to 300 ° C. using a push-bar type measuring device using a standard sample as SiO ₂ . The thermal conductivity was measured by a laser flash method. The results are shown in Table 1. 720 × 9 as the field of view
As a result of observing 50 μm, copper oxide was formed in a dendrite shape, most of which had a particle diameter of 10 to 50 μm, and one lump having a diameter of 100 μm was observed. In addition, there are about 10 rod-shaped and dendrite-shaped ones having a diameter of 30 μm or less and a length of 50 μm or more.
There was a non-formation zone having a width of about 0.5 μm from the above-mentioned rod-like and dendrite-like part where the granular thing of 2 μm or less was dispersed, except for that part, and it was connected in a thread form. Things are also formed.

As is clear from Table 2, the thermal expansion coefficient and the thermal conductivity vary over a wide range by adjusting the composition ratio of Cu and Cu ₂ O. I found that I could control it.

[0048]

[Table 2]

On the other hand, from the microstructure, Cu ₂ O formed a dendrite, and had a dense structure in which the Cu phase and the Cu ₂ O phase were uniformly dispersed.

As a result of the hardness measurement, the Cu phase was Hv 75-8.
0, Cu ₂ O had a hardness of Hv 210 to 230. In addition, as a result of evaluating the machinability by lathe and drill processing,
It was found that the workability was very good, and that the shape was easily imparted.

(C) A cast obtained by unidirectionally solidifying an alloy consisting of 40% by volume of Cu ₂ O and the balance of Cu was hot-worked at 900 ° C. to a workability of 90%, and the workability was sound. The composite material of the present invention was found to be excellent in plastic workability. The orientation became remarkable as compared with the as-cast one, and the Cu ₂ O phase was elongated in the plastic working direction, elongated in one direction, and had a structure having an aspect ratio in the range of 1 to 20. The rod diameter is 20 μm or less,
0 μm is most common. Further, about 15 pieces have a length of 100 μm or more. Further, the fine particles of 0.2 μm or less at the time of casting grow into particles of about 2 to 5 μm and disappear. Further, as also shown in Table 3, more remarkable anisotropy was recognized in the linear expansion coefficient and the thermal conductivity of the sample. In particular, the thermal conductivity showed a value that was 1.22 times higher in the vertical direction along the rod shape than in the horizontal direction. The thermal expansion coefficient is slightly larger in the vertical direction than in the horizontal direction.

[0052]

[Table 3]

(Embodiment 2) FIG. 2 is a sectional view showing the configuration of an electrostatic chuck according to the present invention. The electrostatic chuck includes a base plate 24 provided with cooling or heating holes 23, an electrode plate 22 mounted on the base plate 24, and an insulating layer 21 made of ceramics such as alumina or aluminum nitride. Is supplied with power from the outside.

The electrode plate 22 and the base plate 24 contain 20 to 80% by volume of cuprous oxide (Cu ₂ O), and the balance is copper (C).
u) and inevitable impurities, and is composed of a composite material having a thermal expansion coefficient of 5 × 10 ^{−6 to} 14 × 10 ⁻⁶ / ° C. and a thermal conductivity of 30 to 325 W / m · k from room temperature to 300 ° C. ing. Then, the electrode plates 22 are formed so that the thermal expansion coefficients of both the insulating layer 21 and the base plate 24 match.
The layers are tilted by decreasing the amount of Cu ₂ O in the order of the b and 22c layers. That is, the mixing ratio of cuprous oxide (Cu ₂ O) to copper (Cu) is reduced so that the coefficient of thermal expansion increases stepwise from the bonding surface side with the insulating layer 21 toward the base plate 24 side. It is arranged. As a result, the insulating layer 21
And the electrode plate 22, and the thermal expansion coefficient difference between the electrode plate 22 and the base plate 24 can be reduced.
It is possible to prevent cracking and peeling which cause warpage and foreign matter. Further, since the base plate 24 is provided with low thermal expansion and high thermal conductivity as compared with aluminum or aluminum alloy, thermal deformation is suppressed, and in the case of cooling, the heat is efficiently radiated from the chuck portion 25, and conversely, the heater is heated. In the case where is incorporated, the wafer is efficiently heated.

In the present embodiment, the base plate 24 has a three-layer structure. However, the base plate 24 can be arbitrarily changed according to the size of the apparatus and operating conditions, and the inclination can be obtained by joining the respective layers by brazing or the like. More preferably, when the mixed powder of the raw materials is pressed to produce a preform, a method is preferred in which the mixed powders of the respective layers are laminated, pressed, integrated, and integrated by sintering. By doing so, the joining strength increases,
Thermal conductivity is also improved. The insulating layer 21 is formed by a method such as thermal spraying or vapor deposition, and the chuck portion 25 and the base plate 24 are joined by mechanical fastening, brazing, diffusion bonding, or the like.

(Embodiment 3) FIG. 3 is a sectional view showing the configuration of an electrostatic chuck according to the present invention. The electrostatic chuck has a structure in which an electrode plate is embedded inside an insulating layer. A base plate 34 provided with cooling or heating holes 33 is provided, and an electrode plate 32 is provided inside an insulating layer 31 made of ceramics such as alumina or aluminum nitride placed on the base plate 34. Further, a stress relaxation layer 36 for absorbing thermal stress generated due to a difference in thermal expansion coefficient between the insulating layer 31 and the base plate 34 is provided. The electrode plate 32 is made of molybdenum, tungsten, or the like, and is supplied with power from the outside.

The stress relieving layer 36 and the base plate 34 contain 20 to 80% by volume of cuprous oxide (Cu ₂ O), and the remainder consists of copper (Cu) and unavoidable impurities.
Thermal expansion coefficient at 5 × 10 ^{−6 to} 14 × 10 ⁻⁶ / ° C.
And a composite material having a thermal conductivity of 30 to 325 W / mk. The composite material can arbitrarily select the thermal expansion coefficient by adjusting the amount of Cu ₂ O.
1 and stress relaxation layer 36 and stress relaxation layer 36 and base plate 34
Can be reduced, and cracking and peeling, which cause warpage of the chuck portion 35 and generation of foreign matter, can be prevented.

The insulating layer 41 is formed by a method such as thermal spraying or vapor deposition.
6 is joined by mechanical fastening or brazing. (Embodiment 4) FIG. 4 is a sectional view showing the configuration of an electrostatic chuck according to the present invention. The electrostatic chuck has the same structure as that of the third embodiment, except that the stress relaxation layer is a composite structure and the thermal expansion coefficient is inclined. That is, the stress relaxation layer 46 contains 20 to 80% by volume of cuprous oxide (Cu ₂ O), and the remainder is made of copper (Cu) and unavoidable impurities.
Thermal expansion coefficient at 5 × 10 ^{−6 to} 14 × 10 ⁻⁶ / ° C.
And a composite material having a thermal conductivity of 30 to 325 W / mk. The stress relieving layer 46 has a thermal expansion coefficient matching that of both the insulating layer 41 and the base plate 44.
The amount of Cu ₂ O is graded by the layers a, b, c. That is, the compounding ratio of cuprous oxide (Cu ₂ O) to copper (Cu) is adjusted stepwise so that the coefficient of thermal expansion increases stepwise from the joint surface side with the insulating layer 41 toward the base plate 44 side. Are arranged in a reduced manner. as a result,
The difference in thermal expansion coefficient between the insulating layer 41 and the stress relaxation layer 46 and between the stress relaxation layer 46 and the base plate 44 becomes small,
Since cracking and peeling, which cause warpage and foreign matter, are prevented, the film can be formed at a higher temperature.

(Embodiment 5) FIG. 5 is a sectional view of an electrostatic chuck using the electrostatic chuck described in Embodiments 2 to 4.

As shown in the drawing, the present electrostatic chucking apparatus can be used as an electrostatic chuck of a sputtering apparatus for processing a workpiece 90 made of a conductor or a semiconductor in a reduced-pressure atmosphere inside a vacuum processing chamber 95. . The voltage (500 V) from the DC power supply 91 is applied to the base plate 94 of the electrostatic chuck.
When the degree is applied, the article to be processed 90 can be adsorbed on the surface of the chuck section 92.

Now, in actual sputtering,
After the article to be treated 90 is mounted on the electrostatic suction device, the exhaust pump connected to the gas exhaust port 97 is driven, so that the vacuum inside the vacuum processing chamber 95 is reduced to about 1 × 10 ⁻³ Pa. Exhaust. Thereafter, by opening a valve attached to the gas inlet 96, a reaction gas (argon gas or the like) is introduced into the vacuum processing chamber 95 by 10 SCC.
About M are introduced. At this time, the internal pressure of the vacuum processing chamber 95 is about 2 × 10 ⁻² Pa.

Thereafter, a high-frequency power (about 13.56 kW) of about 4 kW was supplied from the high-frequency power supply 93 of the base plate 94 of the present electrostatic chuck.
MHz), plasma is generated between the base plate 94 of the present electrostatic chuck and another electrode (not shown). In this case, the high frequency applied voltages _VDC and V
_PP is 2 kV and 4 kV. The matching box 98 inserted between the base plate 94 and the high-frequency power supply 93 of the present electrostatic suction device has an impedance matching with the vacuum processing chamber 95 so that the high-frequency power is efficiently supplied to the plasma. It is for taking.

As a result of actually using this sputtering apparatus, the temperature of the article to be processed 90 reached about 450 ° C. during processing, but the chuck portion 92 of the present electrostatic chuck apparatus has cracks which cause foreign matter to be generated. Was not recognized. This means that the use of the present electrostatic suction device is useful for improving processing reliability.

In addition to the sputtering apparatus, a processing apparatus for processing a workpiece made of a conductor or a semiconductor (for example, a silicon substrate) in a reduced-pressure atmosphere (so-called processing apparatus under reduced pressure), for example, a chemical vapor deposition apparatus, It goes without saying that the same effect of improving the reliability of processing can be achieved even when the present electrostatic chucking device is used as a chuck for a physical vapor deposition device, a milling device, an etching device, an ion implantation device and the like.

According to this embodiment, the heat resistance can be improved without lowering the dielectric breakdown strength of the chuck portion of the electrostatic chuck. Therefore, if the electrostatic suction device according to the present invention is used as a chuck for a processing device under reduced pressure, it is possible to reduce the generation of foreign matter due to cracks in the dielectric plate.

The electrostatic attraction device of the present invention is not limited to a sputtering device, but a processing device for processing a workpiece made of a conductor or a semiconductor (for example, a silicon substrate) in a reduced-pressure atmosphere (a so-called low-pressure processing device). For example, even if the present electrostatic chuck is used as a chuck for a chemical vapor deposition apparatus, a physical vapor deposition apparatus, a milling apparatus, an etching apparatus, an ion implantation apparatus, etc., the same effect of improving processing reliability is achieved. Needless to say.

[0067]

According to the present invention, the electrode plate, the stress relieving layer or the base plate has a low thermal expansion and high thermal conductivity.
By using a Cu ₂ O composite material and additionally adjusting the thermal expansion coefficient of the composite material, the difference in the thermal expansion coefficient between the insulating layer and the electrode plate or between the insulating layer and the base plate can be reduced. Cracks, which may cause warpage or foreign matter of the electro chuck,
Peeling can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional configuration view of an electrostatic chuck according to the present invention.

FIG. 2 is a sectional configuration diagram of the electrostatic chuck of the present invention.

FIG. 3 is a sectional configuration diagram of the electrostatic chuck of the present invention.

FIG. 4 is a sectional configuration diagram of the electrostatic chuck of the present invention.

FIG. 5 is a cross-sectional view of the electrostatic suction device of the present invention.

[Explanation of symbols]

11, 21, 31, 41 ... insulating layers, 12, 22, 32,
42 ... electrode plate, 22a ... electrode plate a layer, 22b ... electrode plate b
Layer, 22c... Electrode plate c layer, 15, 25, 35, 45, 9
2: chuck part, 13, 23, 33, 43: cooling or heating hole, 14, 24, 34, 44, 94: base plate, 3
6, 46: stress relaxation layer, 46a: stress relaxation a layer, 46b
... stress relaxation b layer, 46c ... stress relaxation c layer, 90 ... article to be processed, 91 ... DC power supply, 93 ... high frequency power supply, 95 ...
Vacuum processing chamber, 96 gas inlet, 97 gas outlet, 9
8. Matching box.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Teruyoshi Abe 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Kazutaka Okamoto 7, Omikamachi, Hitachi City, Ibaraki Prefecture No. 1-1 Inside Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Noriyuki Watanabe 1-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Yasuhisa Aono Hitachi, Ibaraki Prefecture 7-1-1, Omika-cho, Hitachi F-term in Hitachi Research Laboratory, Hitachi, Ltd. 3C016 GA10 5F004 AA16 BB22 BB29 5F031 CA02 HA02 HA03 HA17 HA18 HA37 HA38 MA28 MA29 MA31 MA32 NA05 PA11 PA30 5F045 BB14 EM05 EM09

Claims (7)

[Claims] 1. An electrostatic chuck comprising: an electrode plate provided on an upper surface with an insulating layer for electrostatically attracting an article to be processed; and a base plate holding the electrode plate and having a cooling or heating structure. An electrostatic chuck, wherein the plate is made of a copper composite material having copper oxide. 2. An electrostatic chuck comprising: an electrode plate provided on an upper surface with an insulating layer for electrostatically adsorbing an article to be processed; and a base plate holding the electrode plate and having a cooling or heating structure. The board is made of a copper composite material having copper oxide,
An electrostatic chuck comprising a copper composite material in which the proportion of copper oxide is reduced so that the coefficient of thermal expansion increases from the insulating layer side toward the base plate side. 3. An electrostatic device comprising: an insulating layer for electrostatically adhering an article to be processed; an electrode plate embedded in the insulating layer; and a base plate holding the electrode plate and having a cooling or heating structure. An electrostatic chuck according to claim 1, wherein a stress relaxation layer is provided between the insulating layer and the base plate to reduce a difference in thermal expansion between the insulation layer and the base plate, and the relaxation layer is made of a copper composite material containing copper oxide. 4. An insulating layer for electrostatically adhering an article to be processed, an electrode plate embedded inside the insulating layer, and a base plate holding the electrode plate and having a cooling or heating structure. In the electrostatic chuck, a stress relaxation layer is provided between the insulating layer and the base plate to reduce a difference in thermal expansion between the insulating layer and the base plate,
The compounding ratio of the copper oxide is reduced so that the relaxation layer is formed of a copper composite material having copper oxide, and the coefficient of thermal expansion increases stepwise from the insulating layer side toward the base plate side. An electrostatic chuck characterized by: 5. The electrostatic chuck according to claim 1, wherein said base plate is made of a copper composite material. 6. The copper composite material according to claim 1, wherein the copper composite material contains 20 to 80% by volume of cuprous oxide (Cu ₂ O).
And the remainder consists of copper (Cu) and unavoidable impurities, has a structure in which the Cu ₂ O phase and the Cu phase are dispersed, and has a coefficient of thermal expansion from room temperature to 300 ° C. of 5 × 10 ^{−6 to} 14 × 1.
An electrostatic chuck characterized by having a thermal conductivity of 0 to ^-6 W / m and a thermal conductivity of 30 to 325 W / mk. 7. A vacuum processing chamber, a vacuum exhaust device for evacuating the vacuum processing chamber, an electrostatic chuck provided in the vacuum exhaust chamber for electrostatically adhering an article to be processed, and applying a voltage to the electrostatic chuck. An electrostatic chuck comprising an applied DC power supply, wherein the electrostatic chuck comprises the electrostatic chuck according to claim 1.