JP2001189378A - Wafer-chucking heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve yield, when heating and treating a wafer by preventing a gap from being locally generated at the part between the wafer and a wafer installation surface due to warpage, distortion, or the like of the wafer, when heat-treating the wafer. SOLUTION: A resistance electrical heating element 3 is embedded inside a ceramic substrate 2, a film-shaped electrode 5 is formed on one main surface 2a of the ceramic substrate 2, and a ceramic dielectric layer 4 is formed at the side of one main surface 2a, so that the film-shaped electrode 5 can be covered. Coulombic fore is generated between a wafer W and the ceramic dielectric layer 4 by a DC power supply 12, the wafer W is attracted to a wafer- attracting surface 6, the resistance electrical heating element 3 is energized for generating heat from the wafer-attracting surface 6, and the attracted wafer W is heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer heating apparatus for a semiconductor manufacturing apparatus and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a semiconductor manufacturing apparatus requiring a super clean state, corrosive gases such as chlorine-based gas and fluorine-based gas are used as a deposition gas, an etching gas, and a cleaning gas. For this reason, when a conventional heater in which the surface of a resistance heating element is coated with a metal such as stainless steel or inconel is used as a heating device for heating a wafer in a state of being brought into contact with such corrosive gas, Exposure generates undesired particles such as chlorides, oxides and fluorides having a particle size of several μm.

[0003] Therefore, an infrared lamp is installed outside the container exposed to the deposition gas or the like, an infrared transmission window is provided on the outer wall of the container, and infrared rays are radiated to a heated body made of a material having good corrosion resistance such as graphite. A wafer heating apparatus of an indirect heating method for heating a wafer placed on an upper surface of an object to be heated has been developed. However, in this method,
The heat loss is large compared to the direct heating type, the temperature rise takes time, and the attachment of the CVD film to the infrared transmission window gradually impedes the transmission of infrared light, causing heat absorption in the infrared transmission window. There are problems such as heating of the window, and deterioration of uniformity and response due to the separation of the heating source and the wafer installation portion.

[0004]

In order to solve the above-mentioned problems, a heating device in which a resistance heating element is newly buried in a disk-shaped dense ceramic has been studied. As a result, it has been found that this heating device is an extremely excellent device that has eliminated the problems described above. However, further examination has revealed that problems remain in the method of holding and fixing the semiconductor wafer.

That is, as conventional semiconductor wafer fixing techniques, there are known mechanical fixing, a vacuum chuck, and an electrostatic chuck. For example, for transporting a semiconductor wafer, exposure, film formation, fine processing, cleaning, Used for dicing and the like.

On the other hand, in particular, in semiconductor wafer heating and temperature control in a film forming process such as CVD, sputtering, or epitaxial growth, if the temperature of the surface to be heated of the semiconductor wafer cannot be made uniform, the yield in semiconductor production is reduced. .
In this case, in mechanical fixing, the film formation becomes uneven due to the contact of the pins or rings with the surface of the semiconductor wafer, and even if the semiconductor wafer is placed on the wafer heating surface of a flat ceramic heater, Sometimes, the entire surface of the semiconductor wafer is not evenly suppressed, so that the semiconductor wafer is warped and distorted,
A gap is locally formed between a portion of the semiconductor wafer and the flat wafer heating surface. And, for example, in a medium-high vacuum of 10 ⁻³ Torr or less, since heat conduction due to convection of gas is very small, a portion of the semiconductor wafer that is in contact with the wafer heating surface and a portion where a gap is formed The temperature difference becomes very large.

That is, the behavior of gas molecules on the wafer installation surface is in a viscous flow region at a pressure of 1 torr or more, and there is heat transfer (heat transfer) by gas molecules. Therefore, the wafer temperature does not drop so much with respect to the heater temperature even in the portion where the above-mentioned gap occurs, and good followability is exhibited. However, when a medium-to-high vacuum is applied, the behavior of gas molecules shifts to the molecular flow region, and the heat transfer by the gas molecules is significantly reduced, so that the wafer temperature is reduced with respect to the heater temperature, resulting in deterioration of uniformity and response. It turns out.

Further, a so-called vacuum chuck cannot be used under conditions of medium and high vacuum such as sputtering and CVD equipment.

Further, there is a so-called electrostatic chuck in which a polyimide film or the like is used as a dielectric film, but the operating temperature range of the conventional electrostatic chuck is about 80 ° to 200 ° C. at the maximum. For this reason, it cannot be installed in a heating device for heating a sputtering or CVD device which can be used up to about 600 ° C.

[0010] In addition, the heater is usually used 200
In the high temperature range of ℃ or higher, the insulation resistance of the dielectric layer,
It has been found that the dielectric breakdown voltage changes significantly and that stable operation is difficult. SUMMARY OF THE INVENTION An object of the present invention is to provide a wafer heating apparatus capable of preventing problems such as contamination as in the case of a metal heater and deterioration of thermal efficiency as in the case of an indirect heating method, and improving uniformity of a heated wafer. It is to provide. Moreover, in a high-temperature region of 200 ° C. or higher, it is possible to suppress a change in the insulation resistance value and the dielectric breakdown voltage of the dielectric layer, thereby enabling a stable operation.

[0011]

SUMMARY OF THE INVENTION The present invention relates to an apparatus for heating a wafer having an operating temperature of 200 ° C. or more and adsorbing a wafer, the base comprising a ceramic sintered body; A resistance heating element buried in the interior of the substrate; a film electrode formed on one main surface of the base; and a dielectric made of a ceramic sintered body formed on one main surface to cover the film electrode. The substrate has a body layer, and is configured such that the wafer can be heated by heat generated by a resistance heating element in a state where the wafer is attracted to the wafer attracting surface of the dielectric layer. Are the same kind of ceramics, and are selected from one or more kinds of ceramics selected from the group consisting of silicon nitride, sialon and aluminum nitride.

In a preferred embodiment of the present invention, the coefficient of thermal expansion of the ceramic substrate is set to 0.7 to 1.4 times the coefficient of thermal expansion of the wafer, or the coefficient of thermal expansion of the ceramic dielectric layer is set to 0.7 to 1.4 times the coefficient of thermal expansion of the wafer. 1.4 times.

In the apparatus of the present invention, the electrostatic chuck electrode may be made of a conductive bonding agent, and the ceramic base and the ceramic dielectric layer may be bonded by this electrode, and the terminal may be connected to the electrode. In order to manufacture this wafer heating apparatus, at least a resistance heating element is embedded in a ceramic green sheet and sintered, a ceramic base in which the resistance heating element is embedded is produced, and the ceramic green sheet is sintered. A ceramic dielectric layer is formed, and one main surface of the ceramic base and the ceramic dielectric layer are joined by a film electrode made of a conductive bonding agent, and terminals are connected to the film electrode. Further, in the device of the present invention, an electrode is attached to the surface of the ceramic dielectric layer, and one main surface of the ceramic base and the surface of the ceramic dielectric layer on the electrode side are joined by an insulating joining agent layer, May be connected to a terminal. In order to manufacture this wafer heating apparatus, at least a resistance heating element is embedded in a ceramic green sheet and sintered, a ceramic base in which the resistance heating element is embedded is produced, and the ceramic green sheet is sintered. A ceramic dielectric layer is formed, a film electrode is formed on the surface of the ceramic dielectric layer, and one main surface of the ceramic substrate and a surface of the ceramic dielectric layer on the film electrode side are joined with an insulating bonding agent. Then, a terminal is connected to the film electrode.

[0014]

FIG. 1 is a schematic partial sectional view showing a wafer heating apparatus 1 according to an embodiment of the present invention. For example, a resistance heating element 3 is embedded inside a disc-shaped ceramic base 2,
The resistance heating element 3 is preferably spirally wound. When the disk-shaped ceramic base 2 is viewed in a plan view, the resistance heating element 3 is provided in a spiral shape. Power supply terminals 8 are respectively connected and fixed to both ends of the resistance heating element 3, and end faces of the respective terminals 8 are joined to a power supply cable 9. Each of the pair of cables 9 is connected to a heater power supply 10, and the resistance heating element 3 can generate heat by operating a switch (not shown).

The disk-shaped ceramic base 2 has opposing main surfaces 2a and 2b. Here, the main surface refers to a surface that is relatively wider than the other surfaces.

One main surface 2a of the disc-shaped ceramic substrate 2
Is formed, for example, a circular film-shaped electrode 5.
Then, a ceramic dielectric layer 4 is formed on one main surface 2a so as to cover the film-shaped electrode 5, and is integrated. As a result, the film electrode 5 is built in between the ceramic base 2 and the ceramic dielectric layer 4. When the film-like electrode 5 has a perforated shape such as a punched metal, the adhesion of the dielectric layer 4 is improved. A terminal 7 is embedded inside the ceramic base 2, one end of the terminal 7 is connected to the membrane electrode 5, and the other end of the electrode terminal 7 is connected to a cable.
11 is connected. This cable 11 is connected to the positive electrode of the electrostatic chuck power supply 12, and the negative electrode of the DC power supply 12 is grounded.
Connected to 13.

When heating the wafer W, the wafer W is placed on the wafer suction surface 6 of the ceramic dielectric layer 4, and the ground wire 13 is brought into contact with the wafer W. Then, the positive charges are accumulated in the film-like electrode 5 to polarize the ceramic dielectric layer 4, and the positive charges are accumulated on the side of the ceramic dielectric layer 4 where the wafer is attracted. At the same time, negative charges are accumulated on the wafer W, and the wafer W is attracted to the wafer attracting surface 6 by Coulomb attraction between the ceramic dielectric layer 4 and the wafer W. At the same time, the resistance heating element 3 is heated to heat the wafer suction surface 6 to a predetermined temperature.

According to such a wafer heating apparatus, it is possible to heat the wafer by simultaneously heating the wafer suction surface 6 while adsorbing the wafer W onto the wafer suction surface 6 by the Coulomb force on the entire surface. Therefore, particularly when the wafer W is heated in a medium-high vacuum, the temperature followability is improved over the entire surface of the wafer W, and the wafer W can be uniformly heated, and the temperature between the wafer W and the wafer heating surface can be increased. The uniformity of the wafer W does not decrease due to the gap. Therefore, the heat treatment of the wafer W can be performed uniformly over the entire surface of the wafer, and for example, in a semiconductor manufacturing apparatus, a decrease in the yield of semiconductors can be prevented.

Further, since the dielectric layer 4 is also made of ceramics, the dielectric layer 4 has high heat resistance and can be favorably used in, for example, a thermal CVD apparatus. At the same time, it is preferable that the dielectric layer 4 is formed of ceramics having durability against abrasion and deformation by the chuck of the wafer more than 10,000 times.

Further, since the resistance heating element 3 is buried inside the ceramic base 2 and the film-like electrode 5 is built in between the ceramic dielectric layer 4 and the ceramic base 2, a conventional metal heater is used. Contamination can be prevented. Further, since the wafer W is directly heated in a state where the wafer W is attracted to the wafer attracting surface 6, there is no problem of deterioration in thermal efficiency as in the case of the indirect heating method.

Although the dielectric layer 4 is formed of ceramics, the ceramics have a characteristic that the insulation resistance (volume resistivity) decreases as the temperature increases, and therefore, for example, an appropriate insulation of about 10 ¹¹ Ω · cm is used. It may be lower than the resistance value, and the leakage current may increase. In this regard, for use in the heating apparatus 1 of the present embodiment, it is preferable that the heating apparatus has an insulation resistance value of 10 ¹¹ Ω · cm or more even in a high temperature range of 500 to 600 ° C., for example. In this regard, silicon nitride (reaction sintering, normal pressure sintering), aluminum nitride, and sialon are preferred.

The ceramic substrate 2 and the ceramic dielectric layer 4 are, for example, up to 6 in a thermal CVD apparatus.
Since it is heated from about 00 ° C. to about 1100 ° C., it is preferable to form from silicon nitride, sialon, and aluminum nitride from the viewpoint of normal heat resistance.

Silicon nitride, sialon and aluminum nitride emit less gas in a high vacuum than oxide ceramics such as alumina. In other words, since the amount of adsorbed gas is small even in a high vacuum, a change in the resistance value of the dielectric, the dielectric breakdown voltage, and the like is small, and the stable operation of the wafer heating apparatus becomes possible.

Of these, when silicon nitride is particularly employed, the overall strength of the heating apparatus 1 is high, the thermal shock resistance of the heating apparatus 1 is high due to the low coefficient of thermal expansion of silicon nitride, and rapid heating and rapid cooling at high temperatures are repeated. The heating device 1 is not damaged even if it is performed. Also,
Since silicon nitride is excellent in corrosion resistance, the durability of the heating device 1 is high even under corrosive gas conditions such as in a thermal CVD device and the life is prolonged.

Further, the ceramic base 2 and the ceramic dielectric layer 4 are preferably made of the same material having the same thermal expansion from the viewpoint of adhesiveness. In view of both the performance as a heater and the performance as an electrostatic chuck, Silicon nitride is preferred.

The coefficient of thermal expansion of the ceramic substrate 2 and the coefficient of thermal expansion of the ceramic dielectric layer 4 are both preferably 0.7 to 1.4 times the coefficient of thermal expansion of the wafer W. Outside this range, the wafer W may be distorted because the wafer W is in close contact with the wafer suction surface 6 during heating. The combination of these materials is
It depends on the material.

In particular, when the wafer W is made of silicon, the coefficient of thermal expansion is 2.6 × 10 ⁻⁶ K ⁻¹ , and 1.82 × 10 ^{−6 to} 3.38 ×
Preferably, the range is 10 ^-6 K ^-1 , and silicon nitride is 2.7
Since it is × 10 ⁻⁶ K ⁻¹ , it is most suitable as the material of the ceramic base 2 and the ceramic dielectric layer 4 in terms of the coefficient of thermal expansion.

This is because the suction force of the wafer W in a vacuum is
100g / cm^TwoBelow, Al with large thermal expansion _TwoO_Three(7 × 10^-6K^-1)
When a wafer is used, a wafer with a thickness of about 0.6 mm
Is expected to be deformed by 0.25%
You. For this reason, the deformation damage to the wafer is enormous.
It is.

The wafer suction surface 6 is preferably a smooth surface, and the flatness is preferably 500 μm or less to prevent the deposition gas from entering the back surface of the wafer W. As the resistance heating element 3, it is suitable to use tungsten, molybdenum, platinum or the like which has a high melting point and excellent adhesion to silicon nitride or the like.

FIG. 2 is a sectional view showing a state before assembling the wafer heating apparatus according to the embodiment of the present invention, and FIG. 3 is a sectional view showing a state after assembling the wafer heating apparatus. In this embodiment, a planar circular ceramic dielectric layer 4A is used.
Is manufactured by sintering a ceramic green sheet. A ring-shaped flange portion 4b is formed on the periphery of the disc-shaped main body 4a of the ceramic dielectric layer,
A disc-shaped recess 4c is formed inside 4b.

A circular sheet 5A made of a conductive bonding agent
, Which also function as electrodes, as described below. In addition, a disc-shaped ceramic substrate 2A
Is manufactured by sintering a ceramic green sheet. A circular through hole 14 for terminal insertion is formed in the center of the ceramic base 2A. One main surface 2a of ceramic base 2A faces film electrode 5A. Ceramic substrate
A pair of massive terminals 8A is exposed on the other main surface 2b of 2A. Each terminal 8A is embedded in the ceramic base 2A,
It is connected to the resistance heating element 3.

The resistance heating element 3 is a disc-shaped ceramic base.
When viewed in a plan view, 2A is buried in a spiral pattern. Further, when viewed more closely, it is formed in a spiral shape. Further, a columnar terminal 7A is prepared. Press molding, tape casting, or the like can be used for forming the ceramic dielectric layer 4A. As for the ceramic base 2A, the resistance heating element 3 and the terminal 8A are embedded in the ceramic material.
After press molding, cold isostatic press molding and the like are performed, hot press sintering, hot isostatic press sintering and the like are performed.

Then, the film electrode 5A is housed in the concave portion 4c and is brought into contact with the surface of the dielectric layer 4A, and the main surface 2a of the ceramic base 2A is brought into contact with the surface of the film electrode 5A. Then, the cylindrical terminal 7A is inserted into the through-hole 14, and the end face 7a is connected to the membrane electrode 5A.
Contact. A powdery bonding agent is interposed between the wall surface of the through hole 14 and the side peripheral surface of the columnar terminal 7A. In this state, the assembly is subjected to a heat treatment, and as shown in FIG. 3, the dielectric layer 4A and the base 2A are joined by the film-like electrode 5A made of a conductive joining agent. At the same time, the columnar terminal 7A is joined and fixed to the through hole 14 of the base 2A. Next, the dielectric layer 4A
Is polished to flatten the wafer suction surface 6.

The cable 11 is connected to the end face 7b of the cylindrical terminal 7, and this cable is connected to the positive electrode of the power source 12 for electrostatic chuck. The negative electrode of the power supply 12 is connected to the ground line 13. Also, a cable 9 is connected to each terminal 8A, and the cable 9 is connected to a heater power supply 10.

When attracting the wafer W, the wafer W is set on the wafer attracting surface 6 and the ground wire 13 is brought into contact with the wafer W. Then, positive charges are stored in the film-like electrode 5A to polarize the dielectric layer 4A, and positive charges are stored on the wafer suction surface 6 side of the dielectric layer 4A. At the same time, negative charges are accumulated on the wafer, and the wafer is attracted to the wafer attracting surface 6 by Coulomb attraction between the dielectric layer 4A and the wafer W. At the same time, the resistance heating element 3 is heated to heat the wafer W.

According to the wafer heating apparatus 1A shown in FIG.
The effects described above can be obtained. In this embodiment, the sintered dielectric layer 4A and the base 2A are joined with a conductive bonding agent, and the formed conductive bonding agent layer is used as it is as a film electrode. There is no need to provide such components, and the structure is very simple, and the number of manufacturing steps is small.

Furthermore, since the flange portion 4b is provided, no discharge occurs between the film-shaped electrode 5A and the semiconductor wafer even under a high vacuum condition, for example, at 10 ^-3 Torr or less.

Further, the present embodiment has a significant feature in the manufacturing method. This will be described step by step. The present inventor has made a great deal of research on a method of manufacturing a heating device having a structure as shown in FIG. That is, first, in FIG.
A film electrode 5 is formed on the surface of the green sheet of the ceramic substrate 2 by screen printing, and a thin ceramic green sheet (for the dielectric layer 4) is laminated thereon.
The method of press-molding this was studied.

However, when the size of the electrostatic chuck is increased, it is extremely difficult to apply a uniform pressure to the laminate. Therefore, even when this laminate was sintered, the thickness of the dielectric layer inevitably varied. Since the thickness of this derivative layer is extremely thin, generally 400 μm or less,
Even with a variation of the order of 10 μm, there was variation in the wafer attraction force on the wafer attraction surface. In particular, in a portion where the dielectric layer is relatively thick, a target attraction force cannot be obtained, and correction of wafer warpage may be insufficient. On the other hand, in a portion where the dielectric layer is relatively thin, the withstand voltage locally decreased. This part determines the withstand voltage of the wafer heating device as a product, so that the withstand voltage of the entire product may be significantly reduced. In addition, when the laminated product was sintered, poor adhesion occurred locally at the interface of the laminated green sheets. This is considered to be due to firing shrinkage. Observation of such poor adhesion by a scanning electron microscope or the like often shows a minute gap of the order of 0.1 to several μm. When such a heating apparatus was used in a semiconductor manufacturing apparatus, the following troubles occurred.

The conditions of use were such that the wafer temperature was set to 450 ° C. under a vacuum in a molecular flow region of 10 ⁻³ Torr or less. When the temperature of the wafer chucked by the electrostatic chuck was monitored by an infrared radiation thermometer, a local region having a temperature different from that of the surroundings was generated on the surface, and the required temperature uniformity (± 3 ° C) could not be secured. , A temperature difference of 150 ° C. or more sometimes occurred. Under the worst conditions, the dielectric layer may be broken by thermal stress.

In the present case, the inventor has studied the clearance at the sheet joint. As a result, the pressure in the gap at the sheet joint also changed under the influence of the pressure in the chamber of the semiconductor manufacturing apparatus. Especially in vacuum
The behavior of gas molecules is in a viscous flow region in a vacuum from atmospheric pressure to 1 Torr, but when the degree of vacuum is further increased, it moves to the molecular flow region, and the heat transfer around the gap is almost exclusively due to radiation. It becomes an adiabatic state. For this reason, it was found that the temperature of the dielectric layer on the gap portion was lowered, and the portion without the gap showed a high temperature due to good heat transfer. As a result, a local region having a temperature different from that of the surrounding was generated.

As described above, when the method conventionally used for manufacturing the electrostatic chuck is diverted to a wafer heating apparatus as shown in FIG. 1 (or FIG. 3), the variation in the thickness of the dielectric layer is reduced. Poor adhesion at the interface between the dielectric layer and the ceramic substrate inevitably occurred. This variation in the thickness of the dielectric layer is also caused by the inclination of the film electrode. Therefore, even if the surface of the dielectric layer is flat-polished after the integral sintering is completed, the thickness of the dielectric layer cannot be made uniform and, of course, the above-mentioned poor adhesion cannot be corrected.

Here, in the method of the present embodiment, since the dielectric layer 4 is manufactured by sintering the ceramic green sheet, the firing shrinkage is completed at the sintering stage, and therefore, the ceramic base 2A No more deformation at the stage of joining.

As described above, in this embodiment, since the dielectric layer 4A is not deformed, the thickness of the dielectric layer 4A can be accurately made uniform by flattening the surface of the dielectric layer 4A. Therefore,
There is no local decrease in the attraction force and no decrease in the dielectric strength.
In addition, there is no gap between the dielectric layer 4A and the base 2A due to shrinkage due to firing, so that it has excellent heat uniformity and thermal shock resistance.

The materials of the ceramic base 2A and the dielectric layer 4A are the same as those described in the first embodiment. Examples of the material of the columnar terminal 7A include Kovar, tungsten, molybdenum, platinum, titanium, nickel and the like. As the conductive bonding agent, for example, a gold solder containing a titanium component, a silver solder containing a titanium component, and the like are preferable. This is because the titanium contained in these brazes diffuses into the ceramics by the heat treatment, so that the bonding strength of each member increases. These have particularly good bondability to silicon nitride. In a heating device used at 300 ° C. or higher, a wafer at room temperature may be sent by a transfer robot and chucked. At this time, thermal shock is applied to the dielectric layer 4A. As a conductive bonding agent, a brazing material made of a soft metal,
For example, when a gold brazing material containing a titanium component is used, stress relaxation occurs due to plastic deformation of the brazing material portion, so that the thermal shock resistance of the heating device is further improved.

According to the procedures shown in FIGS. 2 and 3, a wafer heating apparatus 1A was manufactured. However, the dielectric layer 4A and the substrate 2A were each made of silicon nitride. These are used to press-mold
It was made by sintering at 1800 ° C. Terminal 8A and resistance heating element 3
Made of tungsten. Also, a circular sheet 5A having a thickness of 100 μm was prepared. This composition is 71.3% by weight of silver, copper
27.9% by weight and 0.8% by weight of titanium. In addition, a powdered brazing material of the same material was interposed between the columnar terminal 7A and the through hole 14. In FIG. 2, the assembly was heat treated and brazed while applying a pressure of 50 g / cm ² or more in the vertical direction.
In order to prevent the oxidation of the silver solder containing the titanium component described above, the brazing was performed in an atmosphere having a pressure of 10 ⁻⁵ Torr or less. The heat treatment was performed at 900 ° C. for 60 seconds. It is preferable to raise and lower the temperature to the maximum temperature of 900 ° C. as soon as possible within a range where the ceramic material is not damaged by thermal shock. In this example, since silicon nitride having high thermal shock resistance is used, the temperature is raised and lowered by 600 ° C.
Per hour.

Then, the wafer heating apparatus 1A after the heat treatment is taken out of the heating furnace, and the surface of the dielectric layer 4A is polished,
The thickness was adjusted to, for example, 300 μm.

FIGS. 4 to 8 are cross-sectional views for explaining a manufacturing procedure of the wafer heating apparatus 1B according to another embodiment of the present invention. Members having the same functions as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof may be omitted. First, as shown in FIG. 4, a film electrode 5B is formed on the surface of the dielectric layer 4A on the concave portion 4c side.

Next, as shown in FIG. 5, an insulating bonding agent layer 15 is provided in the recess 4c by coating or the like. At this time, the film-like electrode 5B is covered with the insulating bonding agent layer 15. Next, a disk-shaped base 2A as shown in FIG. 6 is inserted into the recess 4c,
The surface of the base 2A is brought into contact with the insulating bonding agent layer 15 (see FIG. 5). Then, this assembly is heat-treated, and as shown in FIG. 6, the surface of the dielectric layer 4A on the film electrode 5B side and the main surface 2a of the base 2A.
Are bonded by the insulating bonding agent layer 15 after the heat treatment.

Next, as shown in FIG. 7, a circular peeling portion 15 a is provided in the insulating bonding agent layer 15 at the portion of the through hole 14, and a part of the surface of the membrane electrode 5 B is exposed to the through hole 14. . Next, heat treatment is performed in a state where the powder made of the conductive bonding agent is interposed between the columnar terminal and the base 2A, and as shown in FIG.
The cylindrical terminal 7A is joined to the base 2A, and the end surface 7a of the cylindrical terminal 7A
Is brought into contact with the membrane electrode 5B. Then, the wafer suction surface 6
Is polished. Others are the same as the heating device shown in FIG. 2 and FIG.

The wafer heating apparatus 1B was actually manufactured according to the procedures shown in FIGS. However, the film electrode 5B was formed by screen printing of tungsten. After forming the film electrode 5B, the dielectric layer 4A was heated to 120 ° C. or higher to evaporate the organic solvent remaining in the printed film. Both the dielectric layer 4A and the base 2A were formed of silicon nitride. The film electrode 5B may be formed of molybdenum, platinum, or the like.

Glass for sealing was used as the insulating bonding agent. More specifically, oxynitride glass having the following composition was used. Y ₂ O ₃ 30 wt% Al ₂ O ₃ 30 wt% SiO ₂ 30 wt% Si ₃ N ₄ 10 wt%

When the substrate 2A and the dielectric layer 4A were sealed with glass, they were pressurized at a pressure of 50 g / cm ² or more and heated at 1500 ° C. in a nitrogen atmosphere. When joining the columnar terminal 7A to the base 2A, a titanium-deposited silver solder powder having a composition of 71.3% by weight of silver, 27.9% by weight of copper and 0.8% by weight of titanium was used.

In order to prevent oxidation of titanium-deposited silver solder,
The brazing was performed in an atmosphere having a pressure of 10 ^-5 Torr or less. The heat treatment was performed at 900 ° C. for 60 seconds. The temperature was raised and lowered to the maximum temperature at a rate of 600 ° C./hour.
Then, the heating device after the heat treatment is taken out of the heating furnace, the surface of the dielectric layer 4A is polished, and the thickness is reduced to, for example, 300 μm.
m. The terminal 8A and the resistance heating element 3 were formed of tungsten.

FIG. 9 shows a bipolar wafer heating apparatus 1c. In the heating device 1c, two circular through holes 14 are provided in the disc-shaped ceramic base 2B.
, Columnar terminals 7A are inserted and fixed, respectively. On the surface of the concave portion 4c, two planar circular film electrodes 5C are formed. The end face 7a of the terminal 7A is in contact with the vicinity of the center of each of the film electrodes 5C. In FIG. 9, the left terminal 7A is connected to the negative electrode of the DC power
The positive pole of 12A is grounded. Right terminal in FIG.
7A is connected to the positive electrode of DC power supply 12B, and the negative electrode of DC power supply 12B is grounded.

In each of the above examples, the wafer suction surface 6 is directed upward, but the wafer suction surface 6 may be directed downward. In each of the above examples, the shape of the entire heating device is preferably a disk shape in order to uniformly heat the circular wafer W, but may be another shape, for example, a square disk shape, a hexagonal disk shape, or the like.

Such a heating device can be applied to a heating device in an epitaxial device, a plasma etching device, a light etching device, or the like. Further, as the wafer W, not only a semiconductor wafer but also a suction and heating process of a conductor wafer such as an Al wafer or a Fe wafer can be performed.

[0058]

According to the wafer heating apparatus of the present invention, a film-shaped electrode is formed on one main surface of a ceramic base, and a ceramic dielectric layer is formed on one main surface side so as to cover the film-shaped electrode. When forming and adsorbing the wafer on the wafer adsorbing surface of the ceramic dielectric layer, since the base and the dielectric layer are both made of ceramic, for example, thermal CV
It can be used in high heat applications such as D equipment.

Then, a resistance heating element is buried inside the ceramic base, and the wafer is heated by the heat generated by the resistance heating element, so that the wafer is attracted to the entire surface of the ceramic dielectric film by the Coulomb force while being attracted to the wafer. At the same time, the wafer can be heated via the wafer suction surface. Therefore, the temperature can be easily uniformized over the entire surface of the wafer, and no local gap is generated between the wafer and the wafer suction surface (that is, the wafer heating surface) when the wafer is heated. Therefore, the yield during the heat treatment can be improved over the entire surface of the wafer.

Further, since the resistance heating element is heated while the wafer is attracted to the wafer attraction surface of the ceramic dielectric film and heated from the wafer attraction surface to directly heat the wafer, the thermal efficiency is high. In addition, since the ceramic base and the ceramic dielectric layer are selected from silicon nitride, sialon and aluminum nitride and are of the same kind, the dielectric resistance and dielectric breakdown voltage of the dielectric layer can be reduced even at a high temperature of 200 ° C. or higher. Since the change is small and the adhesion and stability between the ceramic dielectric layer and the ceramic substrate are excellent, stable operation is possible and wafer distortion can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic partial sectional view of a wafer heating apparatus 1 according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a state before assembling the wafer heating apparatus according to the embodiment of the present invention.

FIG. 3 is a sectional view showing a wafer heating device 1A.

FIG. 4 is a cross-sectional view showing a state in which a film electrode 5B is formed on the surface of the dielectric layer on the side of the concave portion 4c.

FIG. 5 shows an insulating bonding agent layer on the surface of the dielectric layer on the concave portion 4c side.
FIG. 14 is a cross-sectional view showing a state in which 15 is formed.

FIG. 6 is a cross-sectional view showing a state where a base 2A is bonded to a dielectric layer 4A via an insulating bonding agent layer 15.

FIG. 7 is a cross-sectional view showing a state in which a part of the insulating bonding agent layer 15 is removed in FIG.

FIG. 8 is a cross-sectional view showing a state where a columnar terminal 7A is joined to a base 2A.

FIG. 9 is a sectional view showing a wafer heating device 1C.

[Explanation of symbols]

 1, 1A, 1B, 1C Wafer heating device 2, 2A, 2B Disc-shaped ceramic substrate 2a One main surface 3 Resistance heating element 4, 4A Ceramic dielectric layer 5, 5A, 5B, 5C Film electrode 6 Wafer suction surface 7 , 7A, 8, 8A terminal 9.11 Cable 10 Heater power supply 12, 12A, 12B Electrostatic chuck power supply (DC power supply) 13 Ground wire 14 Circular through hole 15 Insulating bonding agent layer W Wafer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ryusuke Ushikoshi 1-106, Shingu-cho, Handa-shi, Aichi Japan Insulator Shingu-Apartment 206 (72) Inventor, Shinichi Umemoto 62, Kaminogiri, Hiromicho, Toyota-shi, Aichi Prefecture

Claims (9)

[Claims] 1. It has an operating temperature of 200 ° C. or more,
An apparatus for heating a wafer while adsorbing the same, comprising a base made of a ceramic sintered body; a resistance heating element embedded inside the base; and a film-like electrode formed on one main surface of the base. And a dielectric layer made of a ceramic sintered body formed on the one main surface side so as to cover the film-shaped electrode, and the wafer is attracted to a wafer attracting surface of the dielectric layer. In this state, the wafer is heated by heat generated by the resistance heating element, and the base and the dielectric layer are made of the same type of ceramic, and are made of silicon nitride, sialon, and aluminum nitride. A wafer adsorption heating device, wherein the device is selected from one or more ceramics selected from the group consisting of: 2. The apparatus according to claim 1, wherein the coefficient of thermal expansion of the substrate is 0.7 to 1.4 times the coefficient of thermal expansion of the wafer. 3. The apparatus according to claim 1, wherein the coefficient of thermal expansion of the dielectric layer is 0.7 to 1.4 times the coefficient of thermal expansion of the wafer. 4. Apparatus according to claim 1, wherein said membrane electrode is perforated. 5. The apparatus according to claim 4, wherein said electrode is a punched metal. 6. The flatness of the wafer suction surface is 500 μm.
Apparatus according to any one of claims 1 to 5, characterized in that: 7. The device according to claim 1, wherein tungsten, molybdenum or platinum is used in said resistance heating element. 8. A method according to claim 1, wherein a part of said one main surface of said base and said dielectric layer are joined without sandwiching said film-shaped electrode. Device according to one of the claims. 9. The apparatus according to claim 8, wherein said film-shaped electrode is surrounded by a joint portion between said one main surface of said base and said dielectric layer.