JPH0513558A - Wafer heating device and its manufacture - Google Patents

Abstract

PURPOSE:To improve yield of a wafer during heat treatment by preventing local generation of a clearance between the wafer and a wafer mount surface due to warp, distortion, etc., of the wafer while the wafer is heated. CONSTITUTION:A resistance heating element 3 is buried inside a ceramics substrate 2 and a film-like electrode 5 is formed on one main surface 2a of the ceramic substrate 2. A ceramic dielectric layer 4 is formed at the side of the main surface 2a to cover the film-like electrode 5. Coulomb's force 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 heating element 3 is energized to generate heat from the wafer attracting surface 6 and the attracted wafer 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 manufacturing method thereof.

[0002]

2. Description of the Related Art In semiconductor manufacturing equipment requiring a super clean state, a corrosive gas such as chlorine gas or fluorine gas is used as a deposition gas, an etching gas and a cleaning gas. For this reason, if a conventional heater in which the surface of the resistance heating element is coated with a metal such as stainless steel or Inconel is used as a heating device for heating the wafer in contact with these corrosive gases, these gases The exposure produces undesired particles of chloride, oxides, fluorides, etc. with a particle size of a few μm.

Therefore, an infrared lamp is installed outside the container exposed to the deposition gas and the like, and an infrared transmitting window is provided on the outer wall of the container to radiate infrared rays to a heated object made of a material having good corrosion resistance such as graphite. An indirect heating type wafer heating device for heating a wafer placed on the upper surface of an object to be heated has been developed. However, in this method,
Compared to the direct heating type, the heat loss is large, the temperature rise takes a long time, the infrared ray transmission is gradually blocked by the adhesion of the CVD film to the infrared ray transmitting window, and the infrared ray transmitting window absorbs heat. There is a problem that the window is heated, and the heat source and the wafer installation part are separated, so that the heat uniformity and the response are deteriorated.

[0004]

In order to solve the above problems, a heating device in which a resistance heating element is newly embedded in a disc-shaped dense ceramics has been studied. As a result, this heating device was found to be an extremely excellent device that eliminated the above-mentioned problems. However, further investigations revealed that a problem remains in the method of holding and fixing the semiconductor wafer.

That is, as conventional semiconductor wafer fixing techniques, mechanical fixing, vacuum chuck, and electrostatic chuck methods are known. For example, semiconductor wafer transfer, exposure, film formation, fine processing, cleaning, Used in dicing, etc.

On the other hand, in particular, in the semiconductor wafer heating and temperature control in the film forming processes such as CVD, sputtering, and epitaxial, if the temperature of the heated surface of the semiconductor wafer cannot be made uniform, it will cause a decrease in the yield during semiconductor production. .
In this case, with mechanical fixing, the pins or rings come into contact with the surface of the semiconductor wafer, resulting in non-uniform film formation, and even if the semiconductor wafer is placed on the wafer heating surface of a flat plate-shaped ceramics heater, the wafer heating At times, the entire surface of the semiconductor wafer is not uniformly suppressed, so that the semiconductor wafer is warped and warped.
There is a local gap between a portion of the semiconductor wafer and the flat wafer heating surface. Then, for example, in a medium-high vacuum of 10 ^-3 Torr or less, the heat conduction due to the convection of the gas is very small, so that between the portion of the semiconductor wafer that is in contact with the wafer heating surface and the portion where the gap is formed. The temperature difference becomes very large.

That is, the behavior of gas molecules on the wafer mounting surface is in a viscous flow region at a pressure of 1 torr or more, and there is heat transfer (heat transfer) due to gas molecules. Therefore, even in the portion where the above-mentioned gap is generated, the wafer temperature does not decrease much with respect to the heater temperature, and good followability is exhibited. However, the behavior of gas molecules shifts to the molecular flow region when the vacuum is medium to high, and the heat transfer due to the gas molecules is significantly reduced, so that the wafer temperature lowers with respect to the heater temperature, resulting in deterioration of temperature uniformity and responsiveness. I knew that.

The so-called vacuum chuck cannot be used under the 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 maximum. For this reason, it cannot be installed in a heating device that can be used up to about 600 ° C. for heating a sputtering or CVD device.

An object of the present invention is to prevent the problem of contamination such as in the case of a metal heater and the deterioration of thermal efficiency in the case of an indirect heating system, and to improve the thermal uniformity of a wafer to be heated. A wafer heating device is provided.

[0011]

The present invention provides a ceramic substrate; a resistance heating element embedded in the ceramic substrate; a film electrode formed on one main surface of the ceramic substrate; A wafer heating device having a ceramics dielectric layer formed on the one main surface side so as to cover an electrode, wherein the wafer is attracted to a wafer attraction surface of the ceramics dielectric layer, and the resistance heating element is also provided. The present invention relates to a wafer heating device configured to heat this wafer by the heat generation of.

In a preferred embodiment of the present invention, both the ceramic substrate and the ceramic dielectric layer are made of non-oxide ceramics. The coefficient of thermal expansion of the ceramic substrate can be 0.7 to 1.4 times the coefficient of thermal expansion of the wafer. Further, the coefficient of thermal expansion of the ceramics dielectric layer can be 0.7 to 1.4 times the coefficient of thermal expansion of the wafer.

Further, in a preferred aspect of the present invention, the film electrode is made of a conductive bonding agent, the ceramic substrate and the ceramic dielectric layer are bonded by the film electrode, and the terminal is connected to the film electrode. . In order to manufacture such a wafer heating device, at least a resistance heating element is embedded and sintered inside a ceramic green sheet to produce a ceramic substrate in which the resistance heating element is embedded, and the ceramic green sheet is sintered. A ceramic dielectric layer is produced, one main surface of the ceramic substrate and the ceramic dielectric layer are bonded by a film electrode made of a conductive bonding agent, and a terminal is bonded to this film electrode. Further, in a preferred aspect of the present invention, the film electrode is attached to the surface of the ceramic dielectric layer, and one main surface of the ceramic substrate and the surface of the ceramic dielectric layer on the film electrode side are electrically connected. It is joined by the agent layer and the terminal is connected to the film electrode. In order to manufacture such a wafer heating device, at least a resistance heating element is embedded and sintered inside a ceramic green sheet to produce a ceramic substrate in which the resistance heating element is embedded, and the ceramic green sheet is sintered. A ceramic dielectric layer is prepared, a film electrode is formed on the surface of the ceramic dielectric layer, and one main surface of the ceramic substrate and the surface of the ceramic dielectric layer on the film electrode side are bonded with an insulating bonding agent. Then, the terminal is connected to the film electrode.

[0014]

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

The disk-shaped ceramic substrate 2 has main surfaces 2a and 2b facing each other. Here, the main surface means a surface relatively wider than the other surfaces.

One main surface 2a of the disk-shaped ceramic substrate 2
A circular film electrode 5, for example, is formed along the line.
Then, a ceramic dielectric layer 4 is formed and integrated on one main surface 2a so as to cover the film electrode 5. As a result, the film electrode 5 is built in between the ceramic substrate 2 and the ceramic dielectric layer 4. When the film electrode 5 has a perforated shape like punching metal, the dielectric layer 4 has good adhesion. A terminal 7 is embedded inside the ceramic substrate 2, a film electrode 5 is connected to one end of the terminal 7, and a cable is connected to the other end of the electrode terminal 7.
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 the ground wire.
Connected to 13.

When the wafer W is heat-treated, 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, positive charges are accumulated in the film electrode 5 to polarize the ceramics dielectric layer 4, and positive charges are accumulated on the wafer suction surface side of the ceramics dielectric layer 4. At the same time, a negative charge is accumulated on the wafer W, and the wafer W is attracted to the wafer attracting surface 6 by the Coulomb attractive force 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 device, the wafer W can be heated to the wafer suction surface 6 by the Coulomb force while heating the wafer suction surface 6 at the same time. Therefore, especially when the wafer W is heated in a medium-high vacuum, the temperature followability is improved over the entire surface of the wafer W, the wafer W can be uniformized, and the temperature between the wafer W and the wafer heating surface can be increased. The uniformity of the temperature of the wafer W does not decrease due to the gap. Therefore, the heat treatment of the wafer W can be uniformly performed over the entire surface of the wafer, and in a semiconductor manufacturing apparatus, for example, it is possible to prevent a decrease in semiconductor yield.

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

Further, since the resistance heating element 3 is embedded inside the ceramic substrate 2 and the film electrode 5 is built in between the ceramic dielectric layer 4 and the ceramic substrate 2, the conventional metal heater is used. It can prevent such pollution. Further, since the wafer W is directly heated in a state of being sucked onto the wafer suction surface 6, there is no problem of deterioration of thermal efficiency as in the case of the indirect heating method.

Although the dielectric layer 4 is formed of ceramics, the ceramic has a characteristic that the insulation resistance value (volume specific resistance) decreases as the temperature rises. Therefore, for example, a suitable insulation of about 10 ¹¹ Ω · cm is used. It may be lower than the resistance value and the leak current may increase. In this respect, for use in the heating device 1 of the present embodiment, it is preferable to have 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 respect, alumina, beryllia, magnesia, silicon nitride (reaction sintering, atmospheric pressure sintering), boron nitride and aluminum nitride are preferable.

Further, the ceramic base 2 and the ceramic dielectric layer 4 are limited to a maximum of 6 in a thermal CVD apparatus, for example.
Since it is heated from about 00 ° C. to about 1100 ° C., it is preferably formed from alumina, a silicon nitride sintered body, sialon, silicon carbide, aluminum nitride, alumina, a silicon carbide composite material or the like in terms of heat resistance. Especially ceramic substrate 2
Both the ceramic dielectric layer 4 and the ceramic dielectric layer 4 are preferably made of non-oxide ceramics.

This is because non-oxide covalently-bonded ceramics such as SiC and Si ₃ N ₄ emit less gas in a high vacuum than oxide-based ceramics such as alumina. That is, since the amount of adsorbed gas is small, changes in the resistance value of the dielectric material, the breakdown voltage resistance, etc. are small, and stable operation of the heater electrostatic chuck is possible.

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

Further, it is preferable that the ceramic substrate 2 and the ceramic dielectric layer 4 are made of the same material having the same thermal expansion from the viewpoint of adhesion, and both the performance as a heater and the performance as an electrostatic chuck are considered. 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. If it is out of this range, the wafer W is in close contact with the wafer suction surface 6 during heating, so that the wafer W may be distorted. Wafer W
It should be changed depending on the material.

Particularly, 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 ×.
The preferred range is 10 ^-6 K ^-1 , and silicon nitride is 2.7
Since it is × 10 ^-6 K ^-1 , it is most suitable as a material for the ceramic substrate 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 vacuum is
Al ₂ O ₃ (7 × 10 ^-6 K), which has a large thermal expansion under 100 kg / cm ^2.
-1 ) is used, it is expected that a wafer with a thickness of about 0.6 mm will be restrained by the electrostatic chuck and deformed by as much as 0.25%. Therefore, the deformation damage to the wafer is great.

The wafer suction surface 6 is preferably smooth, 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 is excellent in adhesion to silicon nitride or the like.

(Embodiment 2) FIG. 2 is a sectional view showing a state before assembly of a wafer heating apparatus according to an embodiment of the present invention,
FIG. 3 is a sectional view showing a state after the wafer heating device is assembled. In this example, the ceramic dielectric layer 4A having a circular plane shape is produced by sintering a ceramic green sheet. A ring-shaped flange 4b is formed on the peripheral edge of the disk-shaped body 4a of the ceramics dielectric layer, and a disk-shaped recess 4c is formed inside the flange 4b.

A circular sheet 5A made of a conductive bonding agent
This also functions as an electrode, as will be described later. In addition, a disk-shaped ceramic substrate 2A
Is produced by sintering a ceramic green sheet. A circular through hole 14 for inserting a terminal is formed in the central portion of the ceramic base 2A. One main surface 2a of the ceramic base 2A faces the film electrode 5A. Ceramic substrate
A pair of massive terminals 8A are 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 disk-shaped ceramic substrate.
When viewed in plan from 2A, they are buried in a spiral pattern. Also, when viewed in more detail, it is shaped like a spiral. Further, a cylindrical terminal 7A is prepared. Press molding, tape cast molding, or the like can be used for molding the ceramic dielectric layer 4A. Regarding the ceramic base 2A, the resistance heating element 3 and the terminal 8A are placed in the ceramic material.
And are buried, 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 housed in the recess 4c and brought into contact with the surface of the dielectric layer 4A, and further the main surface 2a of the ceramic substrate 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 surface 7a thereof is connected to the film electrode 5A.
Abut. 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 heat treatment, and as shown in FIG. 3, the dielectric layer 4A and the substrate 2A are bonded by the film electrode 5A made of a conductive bonding agent. At the same time, the cylindrical terminal 7A is joined and fixed to the through hole 14 of the base 2A. Then, the dielectric layer 4A
The surface of the wafer is polished to make the wafer suction surface 6 flat.

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

When sucking the wafer W, the wafer W is placed on the wafer suction surface 6 and the ground wire 13 is brought into contact with the wafer W. Then, positive charges are accumulated in the film electrode 5A to polarize the dielectric layer 4A, and positive charges are accumulated on the wafer adsorption surface 6 side of the dielectric layer 4A. At the same time, a negative charge is accumulated on the wafer, and the wafer is attracted to the wafer attracting surface 6 by the Coulomb attractive force 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 already described in the first embodiment can be obtained. Also,
In this embodiment, the sintered dielectric layer 4A and the base body 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 it, the structure is very simple, and the manufacturing process is small.

Further, since the flange portion 4b is provided, no electric discharge occurs between the film electrode 5A and the semiconductor wafer even under a medium or high vacuum condition of, for example, 10 ⁻³ Torr or less.

Further, this embodiment has a great feature in terms of the manufacturing method. This point will be described step by step. The present inventor has conducted extensive studies on a method of manufacturing a heating device having a structure as shown in FIG. That is, first, in FIG.
A film-like electrode 5 is formed on the surface of the green sheet of the ceramic base 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 examined.

However, when the size of the electrostatic chuck was increased, it was extremely difficult to apply a uniform pressure to the laminated product. Therefore, even if this laminated product was sintered, the thickness of the derivative layer inevitably varied. The thickness of this dielectric layer is generally as thin as 400 μm or less, so
Even with variations of the order of 10 μm, there was variation in the wafer suction force on the wafer suction surface. In particular, in a portion where the dielectric layer is relatively thick, the target suction force cannot be obtained, and the warp of the wafer may not be corrected sufficiently. On the other hand, in the portion where the dielectric layer is relatively thin, the withstand voltage locally decreased. This part determines the withstand voltage of the wafer heating device, which is a product, and thus the withstand voltage of the entire product may be significantly reduced. Further, when the laminated product was sintered, a poor adhesion locally occurred at the interface of the laminated green sheets. This is considered to be caused by firing shrinkage. Such a poor adhesion often has a minute gap of the order of 0.1 to several μm when observed by a scanning electron microscope or the like. When such a heating device was used in a semiconductor manufacturing apparatus, the following problems occurred.

The conditions of use were such that the wafer temperature was set to 450 ° C. under vacuum in the molecular flow region of 10 ⁻³ Torr or less. When the temperature of the electrostatically chucked wafer was monitored with an infrared radiation thermometer, a local region with a temperature different from the surroundings was generated on the surface, and the required soaking property (± 3 ° C) could not be secured. In some cases, a temperature difference of 150 ℃ or more occurred. Further, under the worst conditions, the dielectric layer may be destroyed by thermal stress.

With respect to the present case, the inventor examined the gap of the sheet joint portion. As a result, the pressure inside the gap at the sheet bonding portion also changed under the influence of the pressure inside the semiconductor manufacturing apparatus chamber. Especially in vacuum,
The behavior of gas molecules is in the viscous flow region in a vacuum of atmospheric pressure to 1 Torr, but when the degree of vacuum further increases, it moves to the molecular flow region, and along with this, the heat transfer around the skimmer part is mostly due to radiation. And becomes adiabatic. For this reason, it was found that the temperature of the dielectric layer on the gap portion is lowered, and the portion without gap has a high temperature because of good heat transfer. As a result, a local region having a temperature different from that of the surrounding area was created.

As described above, when the method conventionally used for manufacturing the electrostatic chuck is transferred to the wafer heating apparatus as shown in FIG. 1 (or FIG. 3), the variation in the thickness of the dielectric layer and 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 due to the inclination of the film electrode. Therefore, even if the surface of the dielectric layer is flat-polished after the completion of the integral sintering, the thickness of the dielectric layer cannot be made uniform and, of course, the adhesion failure cannot be corrected.

Here, in the method of the present embodiment, since the dielectric layer 4 is produced by sintering the ceramic green sheet, the firing shrinkage has ended at the stage of the sintering, and therefore the ceramic substrate 2A. At the stage of joining with, it no longer deforms.

As described above, since the dielectric layer 4A is not deformed in this embodiment, the thickness of the dielectric layer 4A can be accurately made uniform by planarizing the surface of the dielectric layer 4A. Therefore,
There will be no local decrease in adsorption force or decrease in withstand voltage.
In addition, since there is no gap between the dielectric layer 4A and the base body 2A due to shrinkage due to firing, the thermal uniformity and the thermal shock resistance are excellent.

The materials of the ceramic substrate 2A and the dielectric layer 4A are similar to those described in the first embodiment. Examples of the material of the cylindrical terminal 7A include Kovar, tungsten, molybdenum, platinum, titanium, nickel and the like. As the conductive bonding agent, for example, gold solder containing a titanium component, silver solder containing a titanium component, or the like is preferable. This is because the titanium contained in these brazes diffuses into the ceramic by the heat treatment, so that the bonding force of each member increases. These have particularly good bondability to silicon nitride. Further, 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 braze 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.

A wafer heating apparatus 1A was produced according to the procedure shown in FIGS. However, the dielectric layer 4A and the substrate 2A were each made of silicon nitride. These are press molded
It was made by sintering at 1800 ° C. Terminal 8A, resistance heating element 3,
Made of tungsten. In addition, a circular sheet 5A having a thickness of 100 μm was prepared. This composition is 71.3% by weight silver, copper
27.9% by weight and 0.8% by weight of titanium. Further, a powdered brazing material of the same material as this 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 above-described silver braze containing the titanium component from being oxidized, brazing was performed in an atmosphere of a pressure of 10 ^-5 Torr or less. The heat treatment was carried out 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 in which the ceramic material is not damaged by thermal shock. In this example, since silicon nitride, which has high thermal shock resistance, is used, the temperature rise and fall should be 600 ℃.
It was carried out at a rate of / hour.

Then, after the heat treatment, the wafer heating apparatus 1A 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.

(Embodiment 3) FIGS. 4 to 8 are sectional views for explaining the procedure for manufacturing a 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 designated by the same reference numerals, and the 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 electrode 5B is covered with the insulating bonding agent layer 15. Then, a disk-shaped base body 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 side of the film electrode 5B and the main surface 2a of the substrate 2A.
And are bonded by the insulating bonding agent layer 15 after the heat treatment.

Next, as shown in FIG. 7, a circular peeling portion 15a is provided in the insulating bonding agent layer 15 at the portion of the through hole 14 to expose a part of the surface of the membranous electrode 5B to the through hole 14. . Next, heat treatment is performed with powder made of a conductive bonding agent interposed between the cylindrical terminal and the base body 2A, as shown in FIG.
The cylindrical terminal 7A is bonded to the base 2A, and the end surface 7a of the cylindrical terminal 7A is joined.
Is brought into contact with the film electrode 5B. Then, the wafer suction surface 6
To polish. Others are the same as those of the heating device shown in FIGS. 2 and 3.

A wafer heating apparatus 1B was actually manufactured according to the procedure shown in FIGS. However, the film electrode 5B was formed by screen printing of tungsten. After forming the film-shaped 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 body 2A were made 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 glass-sealed, both were pressurized at a pressure of 50 g / cm ² or more and heated at 1500 ° C. in a nitrogen atmosphere. Further, when the cylindrical terminal 7A was bonded to the base 2A, a titanium vapor deposition silver brazing 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 the oxidation of titanium vapor deposited silver solder,
Brazing was performed in an atmosphere having a pressure of 10 ^-5 Torr or less. The heat treatment was carried out 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 thereof is, for example, 300 μm.
Adjusted to m. The terminal 8A and the resistance heating element 3 were made of tungsten.

(Embodiment 4) Bipolar wafer heating apparatus 1c
Is shown in FIG. In this heating device 1c, two circular through holes 14 are provided in the disk-shaped ceramic substrate 2B, and cylindrical terminals 7A are inserted and fixed in each circular through hole 14. On the surface of the recess 4c, a planar circular film electrode 5C is formed at two locations. The end surface 7a of the terminal 7A is in contact with the vicinity of the center of each film electrode 5C. In FIG. 9, the terminal 7A on the left side is connected to the negative electrode of the DC power supply 12A,
The positive electrode of the DC power supply 12A is grounded. In FIG. 9, the terminal 7A on the right side 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 faced upward, but the wafer suction surface 6 may be faced 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 other shapes such as a square disk shape and a hexagonal disk shape may be used.

Such a heating device can also be applied to a heating device in an epitaxial device, a plasma etching device, an optical etching device, or the like. Further, as the wafer W, not only a semiconductor wafer but also a conductive wafer such as an Al wafer or an Fe wafer can be adsorbed and heat-treated.

[0058]

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

Since the resistance heating element is embedded inside the ceramic substrate and the wafer is heated by the heat generated by the resistance heating element, the wafer is attracted to the wafer attracting surface of the ceramic dielectric film by the Coulomb force. At the same time, the wafer can be heated via the wafer suction surface. Therefore, uniform heating can be easily performed over the entire surface of the wafer, and a local gap does not occur between the wafer and the wafer suction surface (that is, the wafer heating surface) when the wafer is heated. Therefore, the yield at the time of heat treatment can be improved over the entire surface of the wafer.

Further, the resistance heating element is heated in the state where the wafer is attracted to the wafer attracting surface of the ceramic dielectric film, and the wafer is directly heated by causing the heat to be generated from the wafer attracting surface, so that the thermal efficiency is high.

[Brief description of drawings]

FIG. 1 is a schematic partial cross-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 cross-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 concave portion 4c side.

FIG. 5 shows an insulating bonding agent layer 15 on the surface of the dielectric layer on the side of the recess 4c.
It is sectional drawing which shows the state which formed.

FIG. 6 shows a base 2A with a dielectric layer through an insulating bonding agent layer 15.
FIG. 4B is a cross-sectional view showing a state of being bonded to 4A.

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

FIG. 8 is a cross-sectional view showing a state in which a cylindrical terminal 7A is joined to a base body 2A.

FIG. 9 is a sectional view showing a wafer heating apparatus 1C according to an embodiment of the present invention.

[Explanation of symbols]

1, 1A, 1B, 1C Wafer heating equipment 2, 2A, 2B disk-shaped ceramic substrate 2a One main surface 3 Resistance heating element 4, 4A Ceramics dielectric layer 5, 5A, 5B, 5C Membrane electrode 6 Wafer suction surface 7, 7A, 8, 8A terminals 9.11. Cable 10 heater power 12, 12A, 12B Electrostatic chuck power supply (DC power supply) 13 Ground wire 14 Circular through hole 15 Insulating bonding agent layer W wafer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor, Tsunekazu Umemoto             62 Kaminogiri, Hiromi-cho, Toyota City, Aichi Prefecture

Claims (8)

[Claims] 1. A ceramic substrate; a resistance heating element embedded in the ceramic substrate; a film electrode formed on one main surface of the ceramic substrate; and one of the ones so as to cover the film electrode. A wafer heating device having a ceramics dielectric layer formed on a main surface side, wherein the wafer is attracted to a wafer attracting surface of the ceramics dielectric layer, and the wafer is heated by heat generated by the resistance heating element. A wafer heating apparatus configured to be capable. 2. The wafer heating apparatus according to claim 1, wherein both the ceramic base and the ceramic dielectric layer are made of non-oxide ceramics. 3. The wafer heating apparatus according to claim 1, wherein the coefficient of thermal expansion of the ceramic substrate is 0.7 to 1.4 times the coefficient of thermal expansion of the wafer. 4. The wafer heating apparatus according to claim 1, wherein the coefficient of thermal expansion of the ceramic dielectric layer is 0.7 to 1.4 times the coefficient of thermal expansion of the wafer. 5. The film-shaped electrode comprises a conductive bonding agent,
The wafer heating apparatus according to claim 1, wherein the ceramic substrate and the ceramic dielectric layer are joined by the film electrode, and a terminal is connected to the film electrode. 6. The film-shaped electrode is attached to 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 insulating bonding agents. The wafer heating apparatus according to claim 1, wherein the wafer heating apparatus is joined by layers and a terminal is connected to the film electrode. 7. A ceramics green sheet is embedded with at least a resistance heating element and sintered to produce a ceramics base in which the resistance heating element is embedded, and the ceramics green sheet is sintered to form a ceramics dielectric layer. The wafer heating apparatus according to claim 5, wherein the wafer is manufactured, one main surface of the ceramic substrate and the ceramic dielectric layer are bonded to each other by a film electrode made of a conductive bonding agent, and terminals are connected to the film electrode. Manufacturing method. 8. A ceramics green sheet is embedded with at least a resistance heating element and sintered to produce a ceramics base in which the resistance heating element is embedded, and the ceramics green sheet is sintered to form a ceramics dielectric layer. A film electrode is formed on the surface of the ceramic dielectric layer, and one main surface of the ceramic substrate and the film electrode side surface of the ceramic dielectric layer are bonded by an insulating bonding agent, The method for manufacturing a wafer heating apparatus according to claim 6, wherein a terminal is connected to the film electrode.