JPH07161803A - Method of bonding aluminum member to poly-benzimidazole member, electrode structure of electrostatic chuck and its manufacture - Google Patents

Abstract

PURPOSE:To form an airtight bonded face by a method wherein an aluminum member is immersed in a polybenzimidazole solution and, when it is bonded to a molded product, it is heated while the solution is being dropped. CONSTITUTION:A power-supply pin 80 for an aluminum susceptor 6 is immersed in a polybenzimidazole solution, the power-supply pin 80 is then inserted into a polybenzimidazole insulating member 83, a power-supply hole 82 is coated with the polybenzimidazole solution, and the insulating member 83 is inserted. The susceptor 6 is put into a temperature-raising furnace in a state that its bonding face is nearly vertical, its temperature is raised gradually up to 150 to 220 deg.C while the polybenzimidazole solution is being dropped into gaps 84, 86. Polybenzimidazole is cross-linked and hardened, and a polymer layer which is uniform and strong is formed. After that, the upper end part and the lower end part are polished so as to become nearly the same face as the surface and the rear surface of the susceptor 6, and the assembly of a power-supply structure for an electrostatic chuck is completed. Since the airtightness of a bonded face is enhanced, it is possible to prevent the crack of the bonded part due to a temperature change, the leak of a gas and a drop in a high- voltage-resistant characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining an aluminum member and a polybenzimidazole member, an electrode structure for an electrostatic chuck, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, in a semiconductor manufacturing process, for example, a plasma processing apparatus is used to perform various kinds of processing such as plasma etching on an object to be processed such as a semiconductor wafer. In this type of processing apparatus, a holding means for holding and fixing a semiconductor wafer to be processed at the time of processing, for example, a mechanical clamp or an electrostatic chuck sheet using electrostatic force is used.

The structure of a conventional electrostatic chuck will now be described with reference to FIGS. 5 to 7. The electrostatic chuck 2 has an insulating electrostatic chuck sheet 4 made of, for example, a polyimide resin and a circle made of, for example, aluminum. It is composed of a column-shaped mounting table (susceptor) 6. The electrostatic chuck sheet 4 has a thin conductive film 8 such as copper foil or silver foil inside.
Is formed into a circular sheet shape as a whole by being enclosed by the insulating film 5 over substantially the entire surface, and is fixed to the upper mounting surface of the susceptor 6 with an adhesive or the like, and a high DC voltage is applied to the conductive film 8. Thus, the semiconductor wafer W can be suction-held on the upper surface of the sheet by the generated electrostatic force.

An electrode structure for applying a high DC voltage to the conductive film 8 of the electrostatic chuck sheet 4 is formed by penetrating a power supply slit 10 having a length of about 1 cm in the thickness direction of the susceptor 6 made of aluminum. Then, similarly to the electrostatic chuck sheet 4, a power feeding sheet 14 in which a power feeding film 12 such as a copper foil is enclosed in an insulating state by an insulating film 13 is inserted into the slit 10. And this power feeding sheet 1
The upper and lower ends of 4 are bent in the surface direction of the susceptor to form a U shape as a whole, and the insulating film 5 of the electrostatic chuck sheet 4 and the insulating film 13 of the power feeding sheet 14 facing the electrostatic chuck sheet 4 are partially removed, Here, for example, a connecting conductor 1 made of a conductive paste
6, the conductive film 8 of the electrostatic chuck sheet 4 and the power feeding film 12 of the power feeding sheet 14 are electrically connected (see FIG. 5).

In the lower part of the power feeding sheet 14, a part of the insulating film is likewise removed and a connecting conductor 18 made of a conductive paste is embedded therein, and an elastic member such as a spring is attached to the connecting conductor 18 from the side of the susceptor support 20. A power supply contact 24 biased upward by the member 22 is in contact with the power supply contact 24, and is configured to supply electric power from a DC high voltage source (not shown).

The wafer processing temperature is -1 depending on the processing content.
The temperature is changed from a low temperature of 50 ° C. to a high temperature of about + 100 ° C., but cold or warm heat for that purpose is usually supplied from the susceptor support 20 side. At this time, in order to enhance the heat transfer efficiency, a predetermined pressure, for example, atmospheric pressure or 10 Torr, is applied between the susceptor support 20 and the susceptor 6.
A degree of heat transfer gas, for example helium gas, is provided. Further, this helium gas is used as the electrostatic chuck sheet 4
Is also supplied to the interface between the semiconductor wafer W and the interface between the susceptor 6 and the susceptor support 20, and acts to enhance the heat transfer efficiency therebetween.

[0007]

By the way, in such a conventional electrostatic chuck electrode structure, as described above, the temperature of the susceptor 6 is changed from as low as -150 ° C to + 100 ° C depending on the processing content. When it is repeatedly changed over a wide range up to a high temperature of, for example, the adhesive portion between the susceptor 6 made of aluminum and the power insulating film made of polyimide, for example, peels off due to the difference in linear expansion coefficient of both materials,
As described above, leakage of heat transfer gas such as helium enclosed in the joint of each member occurs, or the insulating film itself becomes fragile due to repeated temperature changes, and the insulating film becomes vulnerable when a high DC voltage is applied. This has been a problem because the withstand voltage characteristic is deteriorated or dielectric breakdown occurs, which makes the operation of the processing device unstable.

Further, as a component of the semiconductor processing apparatus,
Aluminum members are widely used from the viewpoints of their workability, economic efficiency, and electrical conductivity. However, in processing equipment, there are many places where electrical insulation is required. An airtight bond with is required. Therefore, even at these joints, problems such as leakage of the enclosed gas, deterioration of withstand voltage characteristics of the insulating member, and dielectric breakdown occur as described above. Especially, in the half-micron era, and even in the quarter-half-micron era, ultrafine etching is performed. When the treatment is carried out in a low temperature environment to realize the above, it becomes a more serious problem.

The present invention has been made in view of the above problems, and an object of the present invention is to make it of aluminum even if the temperature change from low temperature to high temperature is repeatedly performed. A new and improved electrostatic that maintains the airtightness between the susceptor member or the power supply pin and the insulating member and does not cause dielectric breakdown even if a high voltage is applied and the withstand voltage characteristics of the insulating part do not deteriorate. An object is to provide an electrode structure of a chuck and a manufacturing method thereof.

Still another object of the present invention is, more generally, that an aluminum member and a polybenzimidazole member, which is an electrically insulating material, are hermetically joined to each other, and a temperature change from a low temperature to a high temperature is repeatedly performed. Even if it is, the airtightness of the polybenzimidazole member is not impaired and the withstand voltage characteristic of the polybenzimidazole member is not deteriorated, and a new and improved aluminum member is joined to the polybenzimidazole member which is an electrically insulating material. Is to provide a method.

[0011]

In order to solve the above problems, a method for joining an aluminum member and a polybenzimidazole member according to claim 1 is such that the joining surface of the aluminum member is immersed in a polybenzimidazole solution. And a step of joining the aluminum member and the polybenzimidazole member, holding the joining surface in a substantially vertical direction, and dropping the polybenzimidazole solution onto the upper end of the minute gap formed in the joining surface to form a solvent. And heating to above the boiling point temperature to cure the polybenzimidazole solution.

Further, a voltage is applied to the electrostatic chuck, which holds the object to be processed on the mounting surface of the susceptor by electrostatic force, from the back surface of the mounting surface of the susceptor through the power supply pin. The electrode structure includes a power feeding hole formed by penetrating in the thickness direction of an aluminum susceptor, a polybenzimidazole insulating member inserted into the power feeding hole with a first minute gap, and the insulating member. Made of aluminum for penetrating in the thickness direction, and made of aluminum for electrically connecting the electrostatic chuck and the feeder line by inserting a second minute gap into the feeder pin insertion hole. It is characterized by comprising a power supply pin and an adhesive layer formed by curing the polybenzimidazole solution introduced into the first and second minute gaps.

According to a third aspect of the present invention, in the electrode structure of the electrostatic chuck according to the second aspect, the thickness of the adhesive layer formed in each of the first and second minute gaps is 0.1 mm or less. It is characterized by

Further, according to a fourth aspect of the invention, a voltage is applied from the back surface of the mounting surface of the susceptor to the electrostatic chuck that attracts and holds the object to be processed on the mounting surface of the susceptor by a power supply pin. And an insulating member made of polybenzimidazole that is inserted through the aluminum susceptor through the aluminum susceptor in the thickness direction and is inserted with a first minute gap in between. And a feed pin insertion hole formed by penetrating the insulating member in the thickness direction, and a second minute gap is inserted into the feed pin insertion hole to electrically connect the electrostatic chuck and the feed line. In manufacturing an electrode structure including a power supply pin made of aluminum to be connected, the inner wall surface of the power supply hole and the joint surface of the power supply pin are immersed in a polybenzimidazole solution, and then the insulating member is provided in the power supply hole. The power supply pin is inserted into the power supply pin insertion hole, and the power supply hole and the inner wall surface of the power supply pin insertion hole are held in a substantially vertical direction, and a polybenz is provided at the upper end of the first and second minute intervals. It is characterized in that the polybenzimidazole solution is cured by heating it to a temperature above the boiling point of the solvent while dropping the imidazole solution.

The polybenzimidazole used in the present invention is preferably poly-2,2 '-(m-phenylene) -5,5'-bibenzimidazole represented by the following structural formula.

[0016]

[Chemical 1]

The molecular weight of the polybenzimidazole used in the present invention is not particularly limited,
For example, it is preferable to use polybenzimidazole having a number average molecular weight of 2000 to 100,000.

Further, the solvent for preparing the polybenzimidazole solution used in the present invention may be a polar solvent which is generally used in the production of a dry spinning solution of polybenzimidazole. Preferably, the solvent is N, N-dimethylacetamide,
It is at least one solvent selected from the group consisting of N, N-dimethylformamide, dimethylsulfoxide and N-methyl-2-pyrrolidone, and a particularly preferable solvent is N, N-dimethylacetamide having a boiling point of 167 ° C.

Further, in the present invention, by adding terpenes such as kerosene and ketones such as methyl ethyl ketone as a mixed solvent to the solvent, polybenzimidazole can be obtained without impairing the solubility of the solvent. It is possible to improve the drying efficiency and so on.

[0020]

According to the invention as set forth in claim 1, the bonding surface of the aluminum member is once dipped in the polybenzimidazole solution to enhance the affinity of the aluminum member for the polybenzimidazole, and then the preformed polybenz Since it is joined to an imidazole member and heated to a temperature above the boiling point of the solvent while dropping the polybenzimidazole solution on the joint surface, the voids caused by the volatilization of the solvent and the shrinkage during curing of the polybenzimidazole are effectively filled. Therefore, it is possible to form an airtight joint surface.
Moreover, since the coefficient of linear expansion of polybenzimidazole is the same as that of aluminum, 23.6 × 10 ⁻⁶ / ° C., even if the temperature change is repeated, peeling of the joint surface due to the difference in the coefficient of linear expansion was formed. Does not occur on the joint surface.

According to the second aspect of the present invention, the electrical insulation between the susceptor made of aluminum and the feed pin is achieved by the polybenzimidazole material having the same linear expansion coefficient as aluminum, so that the temperature change is repeated. Even if it is applied, the insulating portion does not become brittle and the withstand voltage characteristics do not deteriorate. In addition, since the polybenzimidazole layer filled with the polybenzimidazole solution and cured is formed in the minute gap formed between the aluminum member and the preformed polybenzimidazole member, the joint surface is airtightly configured. . Further, there is no problem in the affinity between the polybenzimidazole layer and the polybenzimidazole member, and it is possible to form a stable joint surface that can withstand a temperature change.

According to the third aspect of the present invention, the minute interval filled with the polybenzimidazole solution is 0.1.
Since it is set to be equal to or less than mm, the polybenzimidazole solution dropped at the time of heating and curing stays within a minute interval, and it is possible to form an airtight and stable joint surface.

According to the third aspect of the present invention, the joining surfaces of the aluminum susceptor and the power feeding pin are once immersed in the polybenzimidazole solution, so that the joining surface of the aluminum susceptor and the power feeding pin is polybenz. After increasing the affinity for imidazole, it is joined to a preformed insulating member made of polybenzimidazole, and the polybenzimidazole solution is added dropwise to the minute gaps formed on the joint surface and heated above the boiling temperature of the solvent. Therefore, the voids caused by the volatilization of the solvent and the shrinkage of the polybenzimidazole during curing are effectively filled, so that an airtight joint surface can be formed. Moreover, since the coefficient of linear expansion of polybenzimidazole is the same as that of aluminum, 23.6 × 10 ⁻⁶ / ° C., even if the temperature change is repeated, peeling of the joint surface due to the difference in the coefficient of linear expansion was formed. Does not occur on the joint surface. Further, since the bonding surface between polybenzimidazole and aluminum is also stable, even when a high voltage is applied, the withstand voltage characteristic is not deteriorated and dielectric breakdown does not occur.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which an electrode structure of an electrostatic chuck constructed based on the method and apparatus of the present invention is applied to a plasma etching apparatus will be described in detail below with reference to the accompanying drawings.

As shown, the plasma etching apparatus 3
0 has a processing chamber 36 including an inner frame 32 and an outer frame 34 made of a material such as aluminum. The inner frame 32 includes a cylindrical wall portion 32A, and a bottom portion 32 provided at a slight distance above the lower end of the cylindrical wall portion 32A.
B, and an outer flange portion 32C provided on the outer periphery of the lower end of the cylindrical wall portion 32A. On the other hand, the outer frame 34 is composed of a cylindrical wall portion 34A and a ceiling portion 34B, and is placed on the outer flange portion 32C so as to cover the inner frame 32 in an airtight manner.

Above the cylindrical wall portion 34A of the outer frame 34, a gas can be introduced into the processing chamber 36 from a processing gas source (not shown) into the processing chamber 36 through a mass flow controller (not shown). A conduit 38 is provided. Further, a gas exhaust pipe line 40 is provided below the other side of the cylindrical wall portion 34A so that a vacuum pump (not shown) can evacuate the gas.

Above the ceiling portion 34B of the outer frame 34, a magnetic field generator for forming a horizontal magnetic field on the surface of an object to be processed, for example, a semiconductor wafer W, for example, a permanent magnet 42 is rotatably provided. The magnetron discharge is configured to be generated by forming a horizontal magnetic field by the magnet and an electric field orthogonal to the horizontal magnetic field.

In the processing chamber 36, a susceptor assembly 44 for mounting and fixing an object to be processed, for example, the semiconductor wafer W is arranged. This susceptor assembly 4
4 is mounted on the bottom portion 32B of the inner frame 32 via a plurality of insulating members 46, and at the same time, insulation is provided between the side surface of the susceptor assembly 44 and the cylindrical wall portion 32 of the inner frame 32. Since, for example, an O-ring 48 is inserted as a seal member, the susceptor assembly 44 is
It is configured to be held in an insulated state from the inner frame 32 and the outer frame 34 that are grounded externally.

The susceptor assembly 44 is made of, for example, aluminum and has a three-layer structure in the illustrated example. The susceptor 6 and the susceptor support base 20 for supporting the susceptor 6 are provided under the susceptor 6. It is composed of a jacket housing 50. And this susceptor 6
The electrostatic chuck sheet 4 is adhered to the mounting surface of the upper surface of the above with an adhesive or the like to form the electrostatic chuck 52. Then, the semiconductor wafer W as the object to be processed is suction-held on the electrostatic chuck sheet 4.

The susceptor support 20 is provided with a temperature adjusting device, such as a heater 54, for adjusting the temperature of the semiconductor wafer W. The heater 54 is connected to a heater controller (not shown), and is configured to perform temperature control according to a signal from a temperature sensor (not shown) that monitors the temperature of the susceptor 6.

The susceptor 6 is the susceptor support base 2
It is removably fixed to 0 by using a connecting member such as a bolt 56. With this configuration, the high frequency power source 58
Separately from the susceptor support 20 connected to
It becomes possible to replace only the above 6 parts of the susceptor,
Maintenance of the device becomes easy.

As described above, since the O-ring 48 is interposed between the side wall of the susceptor 6 and the inner surface of the cylindrical wall portion 32A of the inner frame 32, the processing gas introduced into the processing chamber is It does not reach below the susceptor support 20, and contamination of these parts is prevented.

Inside the cooling jacket accommodating table 50, a cooling jacket 62 for accumulating a coolant 60 such as liquid nitrogen is installed. The cooling jacket 62 is connected to a liquid nitrogen source 68 by a pipe 64 via a valve 66. A liquid level monitor (not shown) is arranged in the cooling jacket 62, and by opening and closing the valve 66 in response to a signal from the liquid level monitor, the refrigerant 60 in the cooling jacket 62, for example, the liquid. It is configured to control the supply amount of nitrogen. Further, the bottom surface of the inner wall of the cooling jacket 62 is formed, for example, in a porous form so that nucleate boiling can be caused.
For example, it can be maintained at -196 ° C.

The susceptor assembly 44 thus configured is insulated from the inner frame 32 and the outer frame 34 forming the processing chamber 36 by the insulating member 46 and the O-ring 48, and is electrically the same. The high frequency power supply 58 is connected to the susceptor support 20 via a matching device 69, which constitutes a polar cathode coupling. Thus, the susceptor assembly 8
The counter electrode is constituted by the ceiling portion 34B of the outer frame 34 that is grounded, and by applying high-frequency power, it is possible to generate plasma discharge between the electrodes, that is, in the processing chamber 36.

Further, between the susceptor 6 in the upper layer of the susceptor assembly 8 according to the present embodiment and the susceptor support 20 in the middle layer provided with the heater 54, and between the susceptor support 20 and the lower cooling jacket accommodating portion 50. Gaps 70 and 72 are formed between
These gaps are formed by the sealing member 7 such as an O-ring.
4 and 76 are airtightly constructed,
It is also possible to supply an inert gas having a predetermined pressure, for example, 1 atm, such as helium or argon, through the gas supply line 78.

The gaps 70 and 72 are 1 to 100 μm.
m, and preferably about 50 μm. By the action of the medium enclosed in these gaps 70 and 72, the cooling heat from the cooling jacket 62 can be transferred with a minimum heat loss, and by avoiding the vacuum state, the discharge phenomenon at the feeding point can be effectively performed. It is possible to prevent it.

On the other hand, the electrostatic chuck 52 according to the present invention.
As shown in FIG. 2, is composed of an electrostatic chuck sheet 4 made of, for example, polyimide having an insulating property and a cylindrical susceptor 6 made of, for example, aluminum. The electrostatic chuck sheet 4 is formed by laminating a pair of polyimide resin films 4A and 4B, and a thin conductive film 8 such as a copper foil is enclosed in an insulating state in the electrostatic chuck sheet 4. A DC voltage is applied to the conductive film 8 by the electrode structure constructed according to the present invention, that is, via the power supply pin 80 provided through the susceptor 6 made of aluminum.

That is, the thickness L1 of the susceptor 6 made of aluminum is about 20 mm, and a power feeding hole 82 having a hollow cross section is formed in the thickness direction so as to penetrate therethrough. Then, an insulating member 83 made of polybenzimidazole, which is reduced to a shape substantially similar to the cross-sectional shape of the power feeding hole 82 by the method configured according to the present invention, covers the first gap 84 in the power feeding hole 82. Be inserted and fixed. Further, a power supply pin insertion hole 85 having a hollow circular cross section is formed at a substantially central portion of the insulating member 83 so as to penetrate in the thickness direction thereof. Then, in the power feeding pin insertion hole 85, a power feeding pin 80 made of, for example, aluminum, which is reduced to a shape substantially similar to the power feeding pin insertion hole 85 by the method configured according to the present invention, has a second gap 86. Be inserted and fixed.

Further, the thickness L2 of the insulating member 83 is set to a distance such as at least 1.0 mm or more so as to maintain a sufficient insulating property against a DC high voltage for the electrostatic chuck. The thickness of the first and second gaps 84 and 86 is 0.1 mm or less, preferably 0.02 mm or less. By setting the first and second gaps 84 and 86 to have such dimensions, the aluminum member and the polybenzimidazole member are accurately positioned in the manufacturing process described later, and the polybenzimidazole solution penetrates into the gap during heating. The vertical state can be maintained without interfering with the above, and an airtight polybenzimidazole layer can be formed.

The polybenzimidazole constituting the insulating member 83 in the present invention is preferably poly-2,2 '-(m-phenylene) -5, represented by the following structural formula.
5'-bibenzimidazole, and its molecular weight is not particularly limited, but for example, the number average molecular weight is 200.
It is preferred to use 0 to 100,000 polybenzimidazoles.

[0041]

[Chemical 2]

Further, this polybenzimidazole exhibits stable quality characteristics in a temperature range from ultra-low temperature of, for example, about -150 ° C. to room temperature or above, and its coefficient of linear expansion is 23.6 × 10 ^-6 / Since it is ℃, it is known that it has a high affinity for aluminum members that are joined in an electrically insulating state regardless of temperature changes.

Next, a method of manufacturing the electrode structure of the electrostatic chuck constructed according to the present invention will be described with reference to FIGS. 3 and 4. First, the aluminum power supply pin 80 is immersed in the polybenzimidazole solution, and the polybenzimidazole solution is applied to the inner wall surface of the power supply hole 82 formed in the susceptor 6. By such a treatment, as shown in FIG. 4A, a thin film of the polybenzimidazole solution is formed on the contact surface with the insulating member 83 made of polybenzimidazole, and the power feeding pin to the power feeding pin insertion hole 86 of the insulating member 83 is formed. It is possible to smoothly insert 80 and insert the insulating member 83 into the power supply pin 84 of the susceptor 6, and increase the affinity of the aluminum member for the polybenzimidazole member, so that the polybenzimidazole that is airtight at the joint portion is formed. It is possible to form layers.

The solvent for preparing the polybenzimidazole solution used in the present invention may be a polar solvent which is generally used in the production of a dry spinning solution of polybenzimidazole. Preferably, the solvent is N, N-dimethylacetamide, N,
At least one solvent selected from the group consisting of N-dimethylformamide, dimethylsulfoxide and N-methyl-2-pyrrolidone, and a particularly preferred solvent is
It is N, N-dimethylacetamide having a boiling point of 167 ° C. Further, by adding terpenes such as kerosene or ketones such as methyl ethyl ketone as a mixed solvent to the solvent, the drying efficiency of polybenzimidazole can be improved without impairing the solubility of the solvent. Is possible.

Then, as shown in FIG. 4 (a), the susceptor 6 fitted with the power supply pin 80 and the insulating member 83 is placed in the temperature rising furnace with the joint surface held in a substantially vertical state,
As shown in FIG. 4 (b), while the polybenzimidazole solution is dropped on the upper ends of the first and second gaps 84 and 86, the temperature is gradually raised from room temperature to about 150 ° C. to 220 ° C. The final temperature depends on the boiling point of the solvent in which polybenzimidazole is dissolved. For example, polybenzimidazole may be added to N, N-dimethylacetamide (DMA).
When a solution dissolved in C) is used, 167 ° C or higher,
By heating to about 180 ° C,
It is possible to volatilize N, N-dimethylacetamide and crosslink and cure polybenzimidazole.
The rate of temperature increase depends on the thickness of the first and second gaps 84 and 86, that is, the thickness of the polybenzimidazole layer to be formed, but is generally performed at 20 ° C./minute or less, and the drying rate is In consideration of this, it is preferable that the heating is performed at more than 15 ° C / min to 20 ° C / min or less.

In order to form a uniform and strong polybenzimidazole layer, it is preferable to maintain the viscosity of the solvent at the time of heating and drying the polybenzimidazole solution at an appropriate value, and it is possible to prevent bubbles from being generated. It is preferable to volatilize and dry the solvent as quickly as possible. Therefore, it is preferable to preheat the susceptor 6, the insulating member 83, the power feeding pin 80, and the polybenzimidazole solution to 50 to 100 ° C., preferably 60 to 70 ° C.

In this way, the first and second gaps 8
While the polybenzimidazole solution was added dropwise to the upper ends of Nos. 4 and 86, the electrode structure constructed according to the present invention was dried and heated in a temperature rising furnace, so that the dropped polybenzimidazole solution contained the first and second polybenzimidazole solutions. Gap 84, 86
Penetrating into the inside, N, N-dimethylacetamide in the solution is evaporated at any time, the polybenzimidazole solution is dried and hardened, and a polybenzimidazole layer is formed between the first and second gaps 84 and 86. . Eventually, the polybenzimidazole solution no longer penetrates into the first and second gaps 84, 86, and then at a predetermined temperature, for example 180 ° C.
By continuing the heat treatment at the above temperature for a predetermined time, for example, for 1 hour, a more uniform and tougher high molecular weight polybenzimidazole layer is formed by thermal condensation and crosslinking of the polybenzimidazole, as shown in FIG. 4 (c). First
And the second gaps 84, 86.

The polybenzimidazole layer formed by drying and curing the polybenzimidazole solution as described above is integrated with the preformed insulating member 83 made of polybenzimidazole, and the power supply pin 80 and the susceptor. The aluminum-made joining surface forming 6 is also tightly joined to form an airtight joining surface. In addition, the coefficient of linear expansion of polybenzimidazole is almost equal to that of aluminum, so even if the temperature changes repeatedly, the joint surface will not be broken and the processing equipment will operate stably. Can be made.

In this way, the insulating member 8 is placed inside the susceptor 6.
3 and the power supply pin 80 are fitted and fixed, and then the upper and lower ends thereof are ground to be substantially flush with the upper and lower surfaces of the susceptor. Assembly of the power feeding structure is completed.

Referring again to FIG. 2, a part of the resin film 4A of the electrostatic chuck sheet at a portion facing the upper end of the power feeding pin 80 has a circular size with a diameter of about 2 mm, as shown in FIG. Only the conductive film 8 is removed so as to reach the conductive film 8, and the power supply pin 80 and the conductive film 8 of the electrostatic chuck sheet 4 are electrically connected to each other with the connecting conductor 18 made of, for example, a silver conductive paste interposed in this portion. There is.

At the bottom of the power supply pin 80, the power is urged upward, that is, toward the susceptor 6 side by an elastic member 22 such as a spring in a pin hole 88 formed in the susceptor support base 20 located below the power supply pin 80. The tips of the contacts 24 are in contact with each other, and the power feeding contact 24 and the power feeding pin 80 are electrically connected. This power supply contact 2
4 is connected to a high-voltage DC source 92 via a conductive wire 90 as shown in FIG. 1, and the conductive film 8 of the electrostatic chuck sheet 4 is connected.
Is configured so that a DC voltage of, for example, 2.0 KV can be applied.

The electrostatic chuck sheet 4 is firmly bonded to the mounting surface of the susceptor with, for example, an epoxy adhesive. Further, as described above, in the gap 70 formed between the lower surface of the susceptor 6 and the upper surface of the susceptor support base 20,
In order to improve the heat transfer characteristics of this portion and to suppress the discharge at the feeding point P2 of the feeding pin 24, an inert gas of about 1 atm, for example, helium gas is introduced. However, in the present embodiment, since the aluminum power supply pin 80 is airtightly fixed to the aluminum susceptor 6 by the polybenzimidazole insulating member 83, this heat transfer gas leaks upward. Therefore, no pressure is exerted on the electrostatic chuck sheet 4 side. Further, according to the present invention, since the aluminum member and the polybenzimidazole member having substantially the same linear expansion coefficient are tightly fixed, even if the temperature change is repeated, cracks or the like are generated in the fixed portion, and Leakage of hot gas or deterioration of withstand voltage characteristics does not occur.

Next, the overall operation of the etching processing apparatus configured as described above will be described. First, the semiconductor wafer W is housed in the processing chamber 36 by a transfer arm (not shown) via a gate valve (not shown), and is placed on the electrostatic chuck sheet 4 provided on the placement surface of the susceptor 6. A DC voltage of, for example, 2.0 KV is applied to the conductive film 8 of the electrostatic chuck sheet 4 from a high voltage DC source 92, and the semiconductor wafer W is adsorbed and held on the mounting surface of the susceptor 6 by the Coulomb force due to polarization. .

The inside of the processing chamber 36 has been evacuated in advance by a vacuum pump (not shown) connected to the gas exhaust pipe 40, and a processing gas such as HF gas is supplied through the gas supply pipe 38. Is supplied while controlling the flow rate, and a predetermined process pressure, for example, 10 ⁻² T is supplied to the inside of the processing chamber 36.
A high frequency power supply, for example, a high frequency of 13.56 MHz is simultaneously applied to the susceptor support 20 and the susceptor 6 which form the lower electrode while maintaining about orr. As a result, plasma is generated between the susceptor 6 and the ceiling portion 34B of the outer frame 34 that constitutes the upper electrode, and at the same time, the permanent magnet 42 provided above the ceiling portion 34B is rotated so that the semiconductor wafer W A magnetic field parallel to this plane can be formed in the vicinity to subject the semiconductor wafer W to highly anisotropic etching.

At the time of the etching process of the semiconductor wafer W, the cold heat from the cooling jacket 62 provided in the cooling jacket housing 50 is transferred to the susceptor support 20, the susceptor 6 and the semiconductor wafer W in sequence, and is transferred to the processing surface. On the other hand, low temperature etching can be performed. At this time, the processing temperature of the semiconductor wafer W is controlled by controlling the heat generation amount of the heater 54 provided on the susceptor support 20. In this case, the cooling jacket housing 50 and the susceptor support 2
0, the gap 72, the susceptor support 20 and the susceptor 6
A heat transfer gas such as helium gas is supplied to the gap 70 between and in order to improve heat transfer characteristics.

According to the present invention, the power supply pin 80 made of aluminum has the insulating member 83 made of polybenzimidazole.
The heat transfer gas does not leak to the back surface of the electrostatic chuck sheet 4 because it is airtightly fixed to the aluminum susceptor 6 via the. In addition, since the linear expansion coefficient of aluminum and that of polybenzimidazole are almost equal, even if the temperature of the electrode part of the electrostatic chuck is repeatedly changed, cracks may occur on the joint surface, heat transfer gas leakage, or insulation It is possible to avoid problems such as deterioration of high-voltage resistance characteristics and dielectric breakdown.

The preferred embodiment of the electrode structure of the electrostatic chuck constructed according to the present invention has been described as applied to the plasma etching apparatus, but the present invention is not limited to this embodiment. INDUSTRIAL APPLICABILITY The present invention can be applied to all processing devices such as an ashing device, a sputtering device, and a CVD device that need to adsorb and hold an object to be processed. Furthermore, although the above-described embodiments have been described by taking the case where the present invention is applied to the electrode structure of the electrostatic chuck as an example, the present invention is not limited to the electrode structure of the electrostatic chuck, and is broader. It will be understood that the present invention can be applied to all cases in which an aluminum member and a polybenzimidazole member having electrical insulation are to be hermetically joined.

[0058]

As described above, according to the present invention,
For example, like an electrode structure of an electrostatic chuck, it is possible to hermetically bond an aluminum susceptor or an aluminum power supply pin to a polybenzimidazole member having an electrically insulating property. Moreover, even if the temperature changes repeatedly at the joint, cracks due to the difference in the linear expansion coefficient of both members do not occur, so it is possible to avoid gas leakage, Since problems such as deterioration in specific high voltage resistance and insulation breakdown due to deterioration of parts do not occur,
The processing device can be stably driven.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a plasma etching apparatus to which an electrode structure of an electrostatic chuck according to the present invention is applied.

FIG. 2 is an enlarged sectional view showing an electrode structure of the electrostatic chuck according to the present invention.

FIG. 3 is an exploded view of the electrode structure of the electrostatic chuck according to the present invention.

FIG. 4 is an explanatory view showing a process of manufacturing the electrode structure of the electrostatic chuck according to the present invention.

FIG. 5 is a sectional view showing a structure of a conventional electrostatic chuck.

6 is an enlarged view showing an electrode structure of the electrostatic chuck shown in FIG.

FIG. 7 is an explanatory diagram showing a state where heat transfer gas leaks in the electrode structure of the electrostatic chuck shown in FIG. 6 and the electrostatic chuck sheet swells.

[Explanation of symbols]

 4 Electrostatic Chuck Sheet 6 Susceptor 8 Conductive Film 16 Connection Conductor 22 Elastic Member 24 Feeding Contact 30 Plasma Etching Device 36 Processing Chamber 44 Susceptor Assembly 52 Electrostatic Chuck 58 High Frequency Power Supply 80 Feeding Pin 82 Feeding Hole 83 Insulating Member 84 First Gap 86 Second gap

Claims (4)

[Claims] 1. When joining an aluminum member and a polybenzimidazole member, a step of immersing a joining surface of the aluminum member in a polybenzimidazole solution, a step of joining the aluminum member and the polybenzimidazole member, and Holding the joining surface in a substantially vertical direction and heating the solution above the boiling point of the solvent while dropping the polybenzimidazole solution onto the upper end of the minute gap formed in the joining surface to cure the polybenzimidazole solution. A method for joining an aluminum member and a polybenzimidazole member, comprising: 2. An electrode structure for applying a voltage from a back surface of a mounting surface of a susceptor to a electrostatic chuck that attracts and holds an object to be processed on a mounting surface of a susceptor through a power supply pin, wherein aluminum is used. Feed hole formed by penetrating the susceptor made in the thickness direction, an insulating member made of polybenzimidazole inserted into the feed hole with a first minute gap, and a thickness direction of the insulating member. A power feed pin insertion hole formed so as to penetrate therethrough; a power feed pin made of aluminum that is inserted into the power feed pin insertion hole with a second minute gap to electrically connect the electrostatic chuck and a power feed line; An electrode structure of an electrostatic chuck, comprising: an adhesive layer formed by curing a polybenzimidazole solution introduced into the first and second minute gaps. 3. The electrode structure of the electrostatic chuck according to claim 2, wherein the adhesive layers formed in the first and second minute gaps each have a thickness of 0.1 mm or less. 4. An electrode structure for applying a voltage from the back surface of the mounting surface of the susceptor to the electrostatic chuck that attracts and holds the object to be processed on the mounting surface of the susceptor by a power supply pin. , A feed hole formed by penetrating in the thickness direction of an aluminum susceptor, a polybenzimidazole insulating member inserted into the feed hole with a first minute gap, and the thickness of the insulating member From a power feed pin insertion hole formed by penetrating in the direction, and a power feed pin made of aluminum which is inserted into the power feed pin insertion hole with a second minute gap and electrically connects the electrostatic chuck and the power feed line. In manufacturing the electrode structure, the inner wall surface of the power feed hole and the joint surface of the power feed pin are immersed in a polybenzimidazole solution, and then the insulating member is inserted into the power feed hole and the power feed pin is inserted. The insertion hole of the feeding pin is inserted into the feed holes and the feed pin inserting an inner wall surface of the hole and held substantially vertically the first and second
A method for manufacturing an electrode structure of an electrostatic chuck, characterized in that the polybenzimidazole solution is added dropwise to the upper ends of the minute intervals and heated to a temperature not lower than the boiling point of the solvent to cure the polybenzimidazole solution.