JP2003347396A - Wafer chucking heating apparatus and wafer chucking apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To heat a wafer to a high temperature of ≥200°C with high heat uniformity under high vacuum conditions. <P>SOLUTION: The wafer chucking heating apparatus has: a substrate composed of a ceramics sintered compact; a resistance electrical heating element buried within the substrate; an electrode formed on one main surface of the substrate; and a dielectric layer composed of a ceramics sintered compact formed on one main surface side to cover the electrode, and the electrode has a planar porous form and is bonded with the substrate and the dielectric layer without a gap. A coulombic force is generated between a wafer and the ceramics dielectric layer to attach the wafer to a wafer-attaching surface, the resistance electrical heating element is energized for generating heat from the wafer-attaching surface, and the attached wafer is heated. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wafer suction heating device and a wafer suction device for a semiconductor manufacturing apparatus.

[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 undesirable particles having a particle size of several μm, such as chlorides, oxides, and fluorides.

[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, semiconductor wafer heating in a film forming process such as CVD, sputtering, epitaxial growth, etc.
In the temperature control, if the temperature of the surface to be heated of the semiconductor wafer cannot be made uniform, the yield during the production of the semiconductor 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, At times, since the entire surface of the semiconductor wafer is not uniformly suppressed, the semiconductor wafer is warped and distorted, and a gap is locally formed between a part of the semiconductor wafer and a flat wafer heating surface. And, for example, 10 ^-3 To
In a medium-high vacuum of rr or less, heat conduction due to gas convection is very small, so the temperature difference between the part of the semiconductor wafer that is in contact with the wafer heating surface and the part where the gap is generated is extremely large. Become.

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, in a so-called electrostatic chuck, a polyimide film or the like is used as a dielectric film, but the operating temperature range of the conventional electrostatic chuck is a maximum of 80 ° to 200 °.
It is about ° C. For this reason, it cannot be installed in a heating apparatus for heating a sputtering or CVD apparatus that 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.
Another object of the present invention is to provide a wafer suction device applicable to such a wafer heating device.

[0011]

SUMMARY OF THE INVENTION A wafer suction heating apparatus according to the present invention is an apparatus for heating a wafer while adsorbing the wafer under a vacuum condition of 10 ^-3 Torr or less. , A resistance heating element embedded in the base, an electrode formed on one main surface of the base, and a ceramic sintered body formed on one main surface side to cover the electrode. A dielectric layer comprising a substrate and a dielectric layer, wherein 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. The material of the layer is made of at least one kind of ceramics selected from the group consisting of silicon nitride, sialon and aluminum nitride, the electrode has a planar perforated shape, and the base and the dielectric layer, Without Characterized in that it joined in.

Further, the wafer suction device of the present invention comprises a base made of a ceramic sintered body, an electrode formed on one main surface of the base, and a base formed on one main surface to cover the electrode. Having a dielectric layer made of a sintered ceramics body, the material of the substrate and the dielectric layer is made of one or more of the same type of ceramics selected from the group consisting of silicon nitride, sialon and aluminum nitride, The electrode has a planar perforated shape, and is joined to the base and the dielectric layer without any gap.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A wafer suction heating apparatus according to an embodiment of the present invention comprises a wafer heating apparatus having a base made of a ceramic sintered body, a resistance heating element embedded inside the base, and a ceramic heating apparatus. A base made of a sintered body;
A wafer suction device having an electrode formed on one main surface of the base and a dielectric layer made of a ceramic sintered body formed on one main surface to cover the electrode is integrally formed. It has become. In the integration, the substrate made of a ceramic sintered body constituting the wafer heating device and the substrate made of the ceramic sintered body constituting the wafer suction device may be the same. Further, in the wafer suction device according to the present embodiment, the material of the base and the dielectric layer is made of one or more of the same type of ceramics selected from the group consisting of silicon nitride, sialon and aluminum nitride, and the electrodes are formed of the base and the base. It is characterized in that it is bonded to the dielectric layer without any gap. This electrode has at least a planar shape including a film-like, sheet-like, and plate-like electrode, and by forming a perforated shape, a state in which there is no gap in the joint surface with the base and the dielectric layer is improved. The structure is easy to form. Note that the gap in the present application is such that when a green compact or the like produced by a method of laminating and pressing a plurality of green sheets and sintering them under normal pressure is inevitably left on the sheet joining surface, Also includes a large gap. Therefore, in the wafer suction device according to the present embodiment, there is preferably no minute gap on the order of 0.1 to several μm. The wafer suction heating apparatus according to the present embodiment has a vacuum in a molecular flow region of 10 ⁻³ Torr or less because there is no gap between the electrode, the base, and the dielectric layer of the wafer suction apparatus integrated with the wafer heating apparatus. Even when the wafer is heated to a high temperature of 200 ° C. or higher under the condition, extremely high uniformity can be secured. As a method of manufacturing such a wafer suction heating apparatus without a gap, for example, the following manufacturing method can be mentioned. At least a resistance heating element is embedded and sintered inside the ceramic green sheet to produce a ceramic base in which the resistance heating element is embedded, and the ceramic green sheet is sintered to produce a ceramic dielectric layer. Is joined to the ceramic dielectric layer by a film-shaped electrode made of a conductive bonding agent, and a terminal is connected to the film-shaped electrode. Also, at least a resistance heating element is embedded in the ceramic green sheet and sintered,
A ceramic substrate in which a resistance heating element is embedded is produced, and a ceramic green sheet is sintered to produce a ceramic dielectric layer. A film electrode is formed on the surface of the ceramic dielectric layer, and one of the ceramic substrates is formed. The main surface and the surface of the ceramic dielectric layer on the film electrode side are joined with an insulating bonding agent, and terminals are connected to the film electrode. In addition,
The ceramic base in which the resistance heating element is embedded can be manufactured by hot press sintering or hot isostatic press sintering. Further, the ceramic dielectric layer and the planar electrode may be integrally sintered with the ceramic base by hot press sintering or hot isostatic press sintering.

[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 by operating a switch (not shown), the resistance heating element 3 can generate heat.

The disk-shaped ceramic substrate 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 2 of the disc-shaped ceramic base 2
A circular film-shaped electrode 5 is formed along the line a. 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 buried 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. The 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 connected to the ground line 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, the negative charges of the wafer W are accumulated, 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 used favorably in, for example, a thermal CVD apparatus. It is preferable to use ceramics having durability against abrasion and deformation due to heat.

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 value (volume resistivity) decreases as the temperature increases, so that an appropriate insulation of, for example, 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 device 1 of the present embodiment, for example, 500 to 600 ° C.
It is preferable to have an insulation resistance value of 10 ¹¹ Ω · cm or more even in the high temperature range of 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 should be changed depending on the material of the wafer W.

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 K ^{-1.
-6 to} 3.38 × 10 ⁻⁶ K ⁻¹ , and silicon nitride is 2.7 × 10 ⁻⁶ K ^−1. It is suitable for the material of the ceramic dielectric layer 4.

This is because Al ₂ O ₃ (7) having a large thermal expansion when the suction force of the wafer W in vacuum is 100 g / cm ^2.
When (× 10 ⁻⁶ K ⁻¹ ) is used, it is expected that a wafer having a thickness of about 0.6 mm is restrained by the electrostatic chuck and undergoes deformation of as much as 0.25%. For this reason, the deformation damage to the wafer is enormous.

The wafer suction surface 6 is preferably a smooth surface, and the flatness is preferably set to 500 μm or less to prevent the deposition gas from entering the back surface of the wafer W. Examples of the resistance heating element 3 include tungsten, molybdenum, and the like having a high melting point and excellent adhesion to silicon nitride or the like.
It is appropriate to use platinum 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, the planar circular ceramic dielectric layer 4 is used.
A is produced 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, and a disc-shaped concave portion 4c is formed inside the flange portion 4b.

A circular sheet 5 made of a conductive bonding agent
Prepare A. This also functions as an electrode, as described later. Also, a disc-shaped ceramic substrate 2
A is produced 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 the ceramic base 2A faces the film electrode 5A. A pair of massive terminals 8A is exposed on the other main surface 2b of the ceramic base 2A. Each terminal 8A is embedded in the ceramic base 2A and connected to the resistance heating element 3.

The resistance heating element 3 is embedded so as to form a spiral pattern when the disc-shaped ceramic base 2A is viewed in plan. Further, when viewed more finely, it is formed in a spiral shape. Also, a columnar terminal 7A is prepared. Press molding, tape cast molding, and the like can be used for forming the ceramic dielectric layer 4A. With respect to the ceramic base 2A, the resistance heating element 3 and the terminal 8A are embedded in the ceramic material, and after press molding, cold isostatic press molding, etc., hot press sintering, hot isostatic press sintering, etc. are performed. .

Then, the film electrode 5A is accommodated in the recess 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 columnar terminal 7A is inserted into the through hole 14, and the end face 7a is brought into contact with the membrane electrode 5A. A powdery bonding agent is interposed between the wall surface of the through hole 14 and the side peripheral surface of the cylindrical 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 a film-like electrode 5A made of a conductive joining agent. At the same time, the cylindrical terminal 7 is inserted into the through hole 14 of the base 2A.
A is joined and fixed. Next, the surface of the dielectric layer 4A is polished to make the wafer suction surface 6 flat.

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 supply 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. With it
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. 3, the described effects can be obtained. Further, 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.

Further, since the flange portion 4b is provided,
For example, even under high vacuum conditions under 10 ^-3 Torr,
No discharge occurs between the film-like electrode 5A and the semiconductor wafer.

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 dielectric layer is generally very thin, 400 μm or less,
Even in the order of several tens of μm, the wafer suction force varied on the wafer suction surface. In particular, in a portion where the dielectric layer is relatively thick, a target attraction force cannot be obtained,
Correction of the warpage of the wafer was sometimes 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. When sintering the laminate, at the interface of the laminated green sheets,
Poor adhesion occurred locally. 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 in 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. , 150 ° C. or more. 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, the dielectric layer 4A
Since the surface of 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, a local decrease in the attraction force and a decrease in the withstand voltage do not occur. In addition, since there is no gap between the dielectric layer 4A and the base 2A due to shrinkage during firing, the uniformity and the thermal shock resistance are excellent.

The materials of the ceramic base 2A and the dielectric layer 4A are the same as those described in the first embodiment. Columnar terminal 7A
Examples of the material include Kovar, tungsten, molybdenum, platinum, titanium, and nickel. 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 a normal temperature may be sent by a transfer robot and chucked. At this time, thermal shock is applied to the dielectric layer 4A. When a brazing material made of a soft metal, for example, a gold brazing material containing a titanium component is used as the conductive bonding agent, stress relaxation occurs due to plastic deformation of the brazing material member, so that the thermal shock resistance of the heating device is further improved.

According to the procedure shown in FIGS. 2 and 3, a wafer heating apparatus 1A was manufactured. However, the dielectric layer 4A, the substrate 2
A was made of silicon nitride. These were produced by sintering a press-formed body at 1800 ° C. The terminal 8A and the resistance heating element 3 were formed of tungsten. In addition, thickness 10
A 0 μm circular sheet 5A was prepared. This composition is silver 7
1.3% by weight, copper 27.9% by weight, titanium 0.8% by weight
It is. In addition, a powdered brazing material of the same material was interposed between the cylindrical 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 is performed by 10 ^-5 To.
The test was performed in an atmosphere having a pressure of rr or less. The heat treatment was performed at 900 ° C. for 60 seconds. This maximum temperature 900
It is preferable to raise and lower the temperature to ° C. as soon as possible as long as the ceramic material is not damaged by thermal shock. In this example, since silicon nitride having high thermal shock resistance is used, the temperature was raised and lowered at a rate of 600 ° C./hour.

Then, the wafer heating apparatus 1A after the heat treatment
Was taken out of the heating furnace, the surface of the dielectric layer 4A was polished, and its 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, the concave portion 4c of the dielectric layer 4A is formed.
A film electrode 5B is formed on the side surface.

Next, as shown in FIG. 5, an insulating bonding agent layer 15 is provided in the recess 4c by coating or the like. On this occasion,
The film-like electrode 5B is covered with the insulating bonding agent layer 15. Next, the disk-shaped base 2A as shown in FIG. 6 is inserted into the recess 4c, and 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-like electrode 5B side and the main surface 2a of the base 2A are joined by the heat-insulating insulating bonding agent layer 15. .

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 film electrode 5 B is exposed to the through hole 14. . Next, a heat treatment is performed with the powder of the conductive bonding agent interposed between the cylindrical terminal and the base 2A, and as shown in FIG. 8, the cylindrical terminal 7A is bonded to the base 2A, and the cylindrical terminal 7A Is brought into contact with the film 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 membrane electrode 5B is
Formed by screen printing of tungsten. After forming the film-like electrode 5B, the dielectric layer 4A is heated to 120 ° C.
The above heating was performed 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 is made of molybdenum,
It may be formed of platinum or the like.

As the insulating bonding agent, sealing glass was used, and 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 are sealed with glass, they are pressed with a pressure of 50 g / cm ² or more.
Heated at 1500 ° C. in a nitrogen atmosphere. When joining the columnar terminal 7A to the base 2A, a titanium vapor-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,
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 was taken out of the heating furnace, the surface of the dielectric layer 4A was polished, and its thickness was adjusted to, for example, 300 μm. Terminal 8A, resistance heating element 3
Was 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, and the cylindrical terminals 7A are inserted and fixed in the multi-circular through holes 14, respectively. On the surface of the concave portion 4c, a planar circular film electrode 5 is provided.
C is formed in two places. The end surfaces 7a of the terminals 7A are 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 supply 12A, and the positive electrode of the DC power supply 12A is grounded.
In FIG. 9, the right terminal 7A is connected to the positive electrode of the DC power supply 12B, and the negative electrode of the 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 heat treatment of a conductor wafer such as an Al wafer or an Fe wafer can be performed.

[0058]

According to the wafer suction heating apparatus of the present invention, a wafer heating apparatus composed of a ceramic substrate having a resistance heating element embedded therein, and a planar electrode formed on one main surface of the ceramic substrate. The wafer suction device, which has a ceramic dielectric layer formed on one main surface so as to cover the electrodes, is integrated, so the wafer is suctioned onto the entire surface of the ceramic dielectric layer by the Coulomb force. 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.

In the wafer suction apparatus according to the present invention, the ceramic base and the ceramic dielectric layer are
Since they are selected from silicon nitride, sialon, and aluminum nitride and are of the same type, even in a high-temperature region of 200 ° C. or more, there is little change in the insulation resistance value and dielectric breakdown voltage of the dielectric layer. Furthermore, since the electrode shape is perforated and the ceramic substrate and the dielectric layer are joined without any gaps, the wafer is kept at 200 ° C. with extremely high uniformity even under vacuum in the molecular flow region of 10 ⁻³ Torr or less. It can be heated to the above high temperature. Therefore, 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-like electrode 5B is formed on the surface of the dielectric layer on the concave portion 4c side.

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

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 where a part of the insulating bonding agent layer 15 is peeled off 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 Membrane 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 Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) H05B 3/74 C04B 35/00 J (72) Inventor Ryusuke Ushikoshi 2-56 Sudacho, Mizuho-ku, Nagoya-shi, Aichi Prefecture No. Japan Insulators Co., Ltd. (72) Inventor Kenichi Umemoto No. 2-56, Suda-cho, Mizuho-ku, Nagoya-shi, Aichi F-term in Japan Insulators Co., Ltd. (Reference) 3K092 PP20 QA05 QB02 QB13 QB32 QB44 QB62 QB74 QC49 RF03 VV22 4G030 AA36 AA37 AA51 AA52 BA09 CA08 GA33 5F031 CA02 HA02 HA03 HA17 HA18 MA28 MA29 NA05 PA11

Claims (5)

[Claims] 1. An apparatus for heating a wafer while adsorbing the wafer under a vacuum condition of 10 ⁻³ Torr or less, comprising: a base made of a ceramic sintered body; and a base embedded in the base. A resistance heating element, an 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 to cover the electrode. In a state where the wafer is attracted to the wafer attracting surface of the dielectric layer, the wafer is heated by the heat generated by the resistance heating element, and the material of the base and the dielectric layer is , Made of one or more of the same type of ceramics selected from the group consisting of silicon nitride, sialon and aluminum nitride, wherein the electrode has a planar perforated shape, the base and the dielectric layer, What A wafer suction heating device characterized in that the wafers are bonded in a stable state. 2. The apparatus according to claim 1, wherein the electrode has a punching metal shape. 3. A base made of a ceramic sintered body, an electrode formed on one main surface of the base, and a ceramic sintered body formed on the one main surface side so as to cover the electrode. The substrate and the dielectric layer are made of at least one kind of ceramics selected from the group consisting of silicon nitride, sialon, and aluminum nitride. A wafer suction device, which has a perforated shape and is joined to the base and the dielectric layer without any gap. 4. The apparatus according to claim 3, wherein the electrode has a punched metal shape. 5. The wafer suction apparatus according to claim 3, wherein the electrode is surrounded at its periphery by a joint having no gap between the base and the dielectric layer.