JP2002170870A - Ceramic substrate and electrostatic chuck for semiconductor fabrication/inspection equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic substrate for a semiconductor fabrication/ inspection equipment that does not adhere any particles on an object to be treated such as silicon wafer or the like, and does not generate short circuit between the conductor circuits formed therein. SOLUTION: The ceramic substrate for the semiconductor fabrication/ inspection equipment comprises a ceramic substrate 1 having conductors 2, 3 and 5 formed therein, and a ceramic layer including the conductors and neighbors thereof, and a ceramic layer lower than the conductor that shows the property of an intragrain fracture when they are fractured, and other ceramic layers those show property of inter grain fracture when they are fractured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic substrate used mainly in a semiconductor manufacturing / inspection apparatus, and to an electrostatic chuck mainly used in a semiconductor manufacturing.

[0002]

2. Description of the Related Art Semiconductors are extremely important products required in various industries.
The silicon wafer is manufactured by slicing a silicon single crystal to a predetermined thickness to produce a silicon wafer, and then forming various circuits and the like on the silicon wafer. In the process of manufacturing such a semiconductor chip, for example, a semiconductor manufacturing apparatus using a ceramic substrate as a base, such as an electrostatic chuck, a hot plate, a wafer prober, and a susceptor, is actively used.

As such a semiconductor manufacturing apparatus, for example, Japanese Patent No. 2587289, Japanese Patent Application Laid-Open No. H10-722
No. 60 discloses a ceramic substrate used for these applications.

[0004]

In such a ceramic heater, even if it expands thermally during heating, the ceramic substrate is unlikely to be warped or distorted, and has a temperature followability to changes in applied voltage and current. It was good.

However, when an object to be heated such as a silicon wafer is heated by a ceramic heater using a ceramic substrate disclosed in the above-mentioned publications, ceramic particles often fall off the ceramic substrate, and this causes the ceramic particles to be removed from the ceramic substrate. It adheres to heated objects and becomes particles, which causes short-circuits or breaks in circuits formed on the silicon wafer, causing defects or preventing adhesion between the silicon wafer and the ceramic substrate. Was sometimes unevenly heated.

On the other hand, when a ceramic substrate having a structure in which no particles are dropped is manufactured in order to prevent the particles from falling, the proportion of pores in the ceramic substrate increases, and the main surface in the ceramic substrate becomes large. When conductors are adjacent to each other in a direction parallel to, or in the case of an electrostatic chuck in which conductors are formed adjacent to each other in a direction perpendicular to the main surface of the ceramic substrate,
In some cases, a short circuit or the like occurs due to electrons jumping in pores existing between conductors (for example, between adjacent resistance heating elements or between an electrostatic electrode and a resistance heating element).

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and does not cause ceramic particles to fall off from a surface of a ceramic substrate on which an object to be processed such as a semiconductor wafer is placed or the vicinity thereof. It is an object of the present invention to obtain a ceramic substrate for a semiconductor manufacturing / inspection apparatus in which a short circuit does not occur between conductors adjacent in a direction perpendicular and parallel to a main surface of a substrate inside a ceramic substrate, and an electrostatic chuck. .

[0008]

Means for Solving the Problems The inventors of the present invention have studied to achieve the above object, and as a result, have found that there is a possibility of short-circuiting, the conductor inside the ceramic substrate and the layer including the vicinity thereof, and the above-mentioned conductor. The lower ceramic layer (hereinafter, also referred to as a lower layer) is a layer having a small number of pores therein and exhibiting the property of grain boundary destruction at the time of destruction. The ceramic layer (hereinafter, also referred to as an upper layer) which leads to the occurrence of a defect is formed as a layer exhibiting the property of intra-particle destruction at the time of destruction. It has been found that particles can be prevented from falling off from the heating surface and its vicinity, and that particles can be prevented from adhering to the object to be processed and a short circuit between internal conductors can be prevented. This has led to the formation.

That is, the present invention relates to a ceramic substrate having a conductor formed therein, wherein the ceramic layer including the conductor and the vicinity thereof and the ceramic layer below the conductor are characterized in that they have a property of grain boundary destruction when broken. And the other ceramic layer is a ceramic substrate for a semiconductor manufacturing / inspection apparatus, characterized by exhibiting the property of intra-particle destruction at the time of destruction. Here, the above-mentioned intragranular fracture refers to a case where, when a fracture cross section is observed, a fracture occurs inside the ceramic particles, not at a boundary between the ceramic particles, and is synonymous with intragranular fracture. On the other hand, the above-mentioned grain boundary fracture refers to a case where a fracture occurs at a boundary of ceramic particles when a fracture cross section is observed.

In the present invention, in the upper layer of the ceramic substrate, for example, a very small amount of an impurity element such as a rare earth element as a sintering aid is added to the raw material powder, or Al ₂
By using oxides such as O ₃ and CaO as sintering aids, the particles constituting the ceramic are firmly adhered to each other,
Prevents the ceramic particles from falling off as a layer having a structure that exhibits the property of intra-particle fracture at the time of fracture, while, in the lower layer of the ceramic substrate, for example, increasing the amount of impurity elements such as rare earth elements, Reduce the number of pores and prevent short circuit between internal conductors. When the amount of the impurity element such as a rare earth element is increased as described above, the layer becomes a layer exhibiting the property of grain boundary destruction at the time of destruction.

[0011] As described above, the upper layer of the ceramic substrate is a layer having a structure exhibiting the property of intra-particle destruction at the time of destruction. In the layer having such a structure, the particles are strongly bonded to each other, and when a large force is applied, the crystal is broken at a certain crystal plane in the particles having a weaker bond than between the particles. Since the bonding force between the particles is large, the particles (particles) hardly fall off from the surface of this layer, and the dropped particles adhere to an object to be processed such as a semiconductor wafer, thereby causing a short circuit or disconnection of a circuit. Or cause failure. Further, when heating a semiconductor wafer or the like, the dropped particles do not hinder the close contact between the semiconductor wafer and the ceramic plate, so that heating of the semiconductor wafer does not become uneven. Note that the number of pores in the upper layer is larger than that in the lower layer, which may be convenient because an object to be processed such as a semiconductor wafer can be easily detached.

On the other hand, the lower layer of the ceramic substrate is sintered by adding a large amount of impurities (sintering aids) such as rare earth elements and the like, and sintering is advanced. Layers. The layer formed at this time has a small proportion of pores present therein and is perpendicular to the main surface of the ceramic substrate between conductors parallel to the main surface of the ceramic substrate (for example, between the positive electrode and the negative electrode of the electrostatic electrode). Shorts due to pores are less likely to occur between conductive conductors (between electrostatic electrodes and resistance heating elements).

When the ceramic substrate is a ceramic substrate in which an electrostatic electrode and a resistance heating element are formed, the ceramic substrate functions as an electrostatic chuck.

In this electrostatic chuck, the upper layer functions as a dielectric film, and an object to be processed such as a semiconductor wafer mounted on the ceramic substrate is attracted to the heated surface by the Coulomb force of the electrostatic electrode. . The dielectric film is a layer having such a structure as to exhibit the property of intra-particle destruction at the time of destruction.Because the particles constituting this layer are firmly joined to each other, the ceramic particles do not fall off from the surface, and the dielectric It is possible to prevent poor adhesion between the object to be processed and the electrostatic chuck due to particles falling off from the surface of the body film and adhering to the object to be processed.

On the other hand, the lower ceramic layer (the layer including the above-mentioned electrostatic electrode and its vicinity, and the ceramic layer below the above-mentioned electrostatic electrode) exhibits the property of grain boundary destruction when broken,
Since the ratio of the pores is small, it is possible to prevent a short circuit between the electrostatic electrodes and between the resistance heating elements, or between the electrostatic electrodes and the lower resistance heating element. In addition, when the RF electrode exists, a short circuit between the electrostatic electrode and the RF electrode and between the RF electrode and the resistance heating element can be prevented.

In the present invention, whether or not the fracture cross section is intragranular fracture or intragranular fracture is confirmed by using an electron microscope photograph at a magnification of 2000 to 5000 times. If the fracture occurs at the grain boundary and the fracture cross section is complex and the shape of the particle appears on the surface, it is a grain boundary fracture, while the fracture occurs within the particle and the fracture surface is relatively flat There is intraparticle destruction.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments. The ceramic substrate of the present invention is a ceramic substrate having a conductor formed therein, wherein the ceramic layer including the conductor and the vicinity thereof, and the ceramic layer below the conductor exhibit the property of grain boundary destruction when broken. Present,
The other ceramic layers are characterized by exhibiting intra-particle fracture properties at the time of fracture.

Further, the electrostatic chuck of the present invention is an electrostatic chuck in which an electrostatic electrode and a resistance heating element are formed inside a ceramic substrate, wherein the layer including the electrostatic electrode and its vicinity is provided. The ceramic layer below the electrostatic electrode exhibits a property of grain boundary fracture at the time of fracture, and the other ceramic layers exhibit a property of intra-particle fracture at the time of fracture.

The ceramic substrate of the present invention functions as the electrostatic chuck of the present invention when the conductor formed therein is an electrostatic electrode and a resistance heating element.
Therefore, in the following description, the description will focus on the electrostatic chuck which is one embodiment of the ceramic substrate of the present invention.

FIG. 1 is a longitudinal sectional view schematically showing the electrostatic chuck of the present invention, FIG. 2 is a sectional view taken along line AA of the electrostatic chuck shown in FIG. 1, and FIG. FIG. 2 is a sectional view taken along line BB of the electrostatic chuck shown in FIG. 1.

In this electrostatic chuck 101, a semicircular arc portion 2a and a comb tooth portion 2 are formed on the surface of a disc-shaped ceramic substrate 1.
b, and an electrostatic electrode layer composed of a chuck negative electrode electrostatic layer 3 also composed of a semicircular arc-shaped part 3a and a comb tooth part 3b, and a comb tooth part 2b and a comb tooth part 3b And a thin ceramic dielectric film 4 is formed on this electrostatic electrode layer.
Although not shown, the ceramic substrate 1 is composed of two layers, an upper layer and a lower layer, whose fracture cross sections have different properties.

The chuck positive electrode electrostatic layer 2 and the chuck negative electrode electrostatic layer 3 have a positive side and a negative side of a DC power supply, respectively.
Is connected to the side, the DC voltage V ₂ is adapted to be applied. A silicon wafer 9 is mounted on the electrostatic chuck 101 and is grounded.

On the other hand, a resistance heating element 5 having a concentric circular shape in plan view as shown in FIG. 3 is provided inside the ceramic substrate 1 for controlling the temperature of the silicon wafer 9. at both ends of the external terminals 13 connected, is fixed, so that the voltages V ₁ is applied. Although not shown in FIGS. 1 and 2, this ceramic substrate 1 supports and raises and lowers a bottomed hole 14 for inserting a temperature measuring element and a silicon wafer 9 as shown in FIG. A through hole 15 for inserting a lifter pin (not shown) is formed.

When a DC voltage V ₂ is applied between the chucking positive electrode electrostatic layer 2 and the chucking negative electrode electrostatic layer 3, the silicon wafer 9 moves between the chucking positive electrode electrostatic layer 2 and the chucking negative electrode electrostatic layer 3. It is adsorbed and fixed to the ceramic dielectric film 4 by an electrostatic action (Coulomb force).

The electrostatic chuck according to the present invention has the above-described configuration, and has, for example, an embodiment as shown in FIGS. In the following, each member constituting the electrostatic chuck and other embodiments of the electrostatic chuck of the present invention will be sequentially described in detail.

In the ceramic substrate constituting the electrostatic chuck of the present invention, an element other than the element constituting the ceramic substrate (for example, boron, sodium, calcium, silicon, oxygen or a sintering aid described later) There is a trace amount of an impurity element such as a rare earth element), and when the ceramic constituting the upper layer is broken, the structure exhibits the property of intraparticle breakage. On the other hand, in the lower layer of the ceramic substrate, elements other than the elements constituting the ceramic substrate are minutely localized at the grain boundaries of the ceramic particles, so that when the ceramic forming the lower layer is broken, the structure exhibits the property of grain boundary destruction. Has become.

The ceramic substrate is composed of the upper layer and the lower layer as described above. The ceramic materials constituting these layers differ in the content of impurities such as rare earth elements, and have the same main components. It consists of material.

The main component of the ceramic material constituting the ceramic substrate is not particularly limited, and examples thereof include a nitride ceramic, a carbide ceramic, and an oxide ceramic.

Examples of the nitride ceramic include metal nitride ceramics, for example, aluminum nitride, silicon nitride, boron nitride, titanium nitride and the like. Further, as the carbide ceramic, metal carbide ceramic,
For example, silicon carbide, zirconium carbide, titanium carbide,
Examples include tantalum carbide and tungsten carbide.

Examples of the oxide ceramic include metal oxide ceramics such as alumina, zirconia, cordierite, and mullite. These ceramics may be used alone or in combination of two or more.

Among these ceramics, nitride ceramics and carbide ceramics are more preferable than oxide ceramics. This is because the thermal conductivity is high. Also, among nitride ceramics, aluminum nitride is most preferred. This is because the thermal conductivity is the highest at 180 W / m · K.

The average particle size of the raw material ceramic powder used for producing a ceramic substrate made of these materials is desirably about 0.2 to 1.5 μm. If the average particle size is too small as less than 0.2 μm, the bulk density of the molded body will be too low and sintering will not easily proceed well, or abnormal grain growth will occur, while the average particle size of the raw ceramic powder is If it exceeds 1.5 μm, the particle size of the ceramic particles after sintering becomes too large, the upper layer exhibits the property of grain boundary fracture, and the lower layer has low flexural strength and fracture toughness of the sintered body.

The above-mentioned impurities such as rare earth elements are usually added in order to enhance the sinterability of the raw material ceramic powder when it is fired. For example, when the added impurities are yttria, The amount of the above-mentioned yttria added when producing the green sheet to be the upper layer of the substrate is 1.
It is desirable that the content be 0 parts by weight or less. When the content exceeds 1.0 part by weight, when the ceramic constituting the upper layer is broken, the property of grain boundary destruction is exhibited, the ceramic particles fall off, and particles are generated on an adsorbed object such as a semiconductor wafer. The addition amount of the above yttria is more preferably 0.5 part by weight or less based on 100 parts by weight of the raw ceramic powder.

On the other hand, in the lower layer of the ceramic substrate, the amount of the above-mentioned yttria is desirably about 1.0 to 20 parts by weight based on 100 parts by weight of the raw ceramic powder. If the amount is less than 1.0 part by weight, the fractured cross section exhibits the property of intra-particle fracture, and the sintering of the ceramic powder is insufficient, so that many pores are present inside the pores and electrons are passed through the pores. Short circuit may occur by jumping,
On the other hand, if it exceeds 20 parts by weight, the strength and thermal conductivity of the fired ceramic substrate may be reduced.

The average particle diameter of the ceramic particles constituting the upper layer of the ceramic substrate is controlled to 2 μm or less, and the average particle diameter of the ceramic particles constituting the lower layer is 2 to 10 μm.
Is desirably controlled within the range. By controlling the average particle diameter of the ceramic particles in such a range, the upper layer of the ceramic substrate exhibits the property of intra-particle fracture and the lower layer exhibits the property of grain boundary fracture.

The average particle size of the ceramic particles is measured as follows. First, five samples are prepared, and 10 points are photographed with an electron microscope for each sample, and the average of the maximum diameter and the minimum diameter is obtained for one particle, and this is defined as the particle diameter of the particle. Similarly, the average of the particle diameters of the particles in the image is obtained, and the average particle diameter of one image is measured. Next, for other images,
Similarly, the average particle diameter is determined, and the average particle diameter is averaged to obtain the average particle diameter of the ceramic particles of the ceramic substrate.

The method for producing a ceramic substrate having such an average particle diameter is not particularly limited, but 0.5% by weight of a sintering aid (yttria) under the conditions described above.
After the addition of the following, it can be manufactured by maintaining the firing temperature at 1600 ° C. or higher and lower than 1800 ° C. when performing the firing process. If the firing temperature is lower than 1600 ° C., the progress of sintering of the ceramic particles may be insufficient. On the other hand, if the firing temperature is 1800 ° C. or higher, the average particle diameter of the ceramic particles in the upper layer of the ceramic substrate may be reduced. 2
In some cases, it may exceed 10 μm in the lower layer.

In some cases, the yttria added when producing the green sheet as the upper layer is hardly present in the sintered body. For example, when 0.5% by weight or less of yttria is added when manufacturing an aluminum nitride sintered body, the yttria diffuses outward during the sintering process and scatters from the surface, so that almost no yttria is contained in the sintered body. No residue. Since the amount of impurities such as the sintering aid present at the grain boundaries is very small in the upper layer, the ceramic particles constituting the upper layer are strongly bonded to each other. Therefore, even if a large force is applied to this upper layer, no destruction occurs at the grain boundaries, and destruction proceeds on the crystal plane where the bonds between atoms in the grains are relatively weak.

The upper layer of the ceramic substrate can also be formed by using ceramic powder fired in an oxidizing atmosphere. In this case, the raw material ceramic powder as described above is mixed with oxygen or air for 500 to 100 times.
It is desirable to heat at 0 ° C.

The upper layer of the ceramic substrate has a thickness of 5 to 5000 μm.
m. This is about the same thickness as the ceramic dielectric film of the electrostatic chuck. However, a material having the same composition as that of the lower layer of about 2 to 2000 μm may exist between the upper layer and the electrostatic electrode. this is,
For example, it is necessary to prevent a short circuit between the positive electrode and the negative electrode of the electrostatic electrode in some cases. Therefore, when there is no such fear, 5 to 50 near the lower part of the electrostatic electrode is used.
An upper layer may be present in the range of 00 μm. Then, the portion excluding the upper layer from the ceramic substrate becomes the lower layer of the ceramic substrate. In this lower layer portion, a resistance heating element formed in a ceramic substrate, or a resistance heating element and an electrostatic electrode are embedded.

The upper layer desirably contains 0.05 to 10% by weight of oxygen. Thereby, the bonding between the particles is strengthened. In order to contain oxygen in the upper layer, for example, a method of baking aluminum nitride powder in an oxidizing atmosphere to obtain a powder having oxygen (alumina) on the surface and then baking the aluminum nitride powder in an oxidizing atmosphere After baking to obtain a powder having oxygen (alumina) on the surface, a method of adding CaO powder and baking, a method of adding CaO powder to aluminum nitride powder and baking in an oxidizing atmosphere are desirable. If the oxygen content is less than 0.05% by weight, sintering does not proceed, and fracture occurs at the grain boundaries, and defects occur, so that the flexural strength at high temperatures decreases. Oxygen or the like segregated at the boundary becomes a defect, and the bending strength at high temperatures also decreases.

The upper layer has a maximum pore size of 50 μm.
And a porosity of 5% or less. If the pore diameter of the largest pore exceeds 50 μm, it becomes difficult to secure the withstand voltage characteristics at high temperatures (especially at 200 ° C. or higher). More preferably, the pore diameter is 10 μm or less. This is because the amount of warpage at 200 ° C. or higher is reduced. Note that, as described above, a certain amount of pores may be present in the upper layer which is a ceramic dielectric film, because the presence of a certain amount of open pores on the surface of the ceramic dielectric film means that a silicon wafer or the like exists. This is because the object to be sucked can be smoothly dechucked.

On the other hand, the lower layer has no porosity or, if porosity exists, its porosity is preferably 5% or less, and the maximum pore size is preferably 50 μm or less. If the porosity exceeds 5%, electrons jump in the pores, and between the electrostatic electrodes and the resistance heating elements formed in the lower layer, and between the electrostatic electrodes and the resistance heating elements. Cannot ensure the insulation properties of

The porosity differs between the upper layer and the lower layer of the ceramic substrate constituting the electrostatic chuck of the present invention. The porosity of the ceramic substrate as a whole is 5% or less, and the maximum pore diameter is It is desirable that it is 50 μm or less. If the porosity exceeds 5%, the number of pores in the ceramic substrate increases, and the pore diameter becomes too large. As a result, the pores easily communicate with each other. This is because the voltage drops. Further, when the pore diameter of the maximum pore exceeds 50 μm,
This is because the ratio of the pore diameter to the thickness of the ceramic substrate increases, and the proportion of the pores communicating with each other also increases, so that the withstand voltage also decreases. The porosity is 0
Or 3% or less is more preferable, and the pore diameter of the maximum pore is
0 or 10 μm or less is more preferable.

The porosity is measured by the Archimedes method. Pulverize the sintered body, put the pulverized material in an organic solvent or mercury, measure the volume, calculate the true specific gravity from the weight and volume of the pulverized material, and calculate the porosity from the true specific gravity and the apparent specific gravity .

In order to measure the pore diameter of the maximum pore, five samples are prepared, and the surfaces thereof are mirror-polished and
The surface is photographed at 10 times with an electron microscope at a magnification of 000 times. Then, the largest pore diameter is selected from the photographed photograph, and 5
The average of 0 shots is defined as the maximum pore diameter.

Next, the characteristics of the entire ceramic substrate including the above-described upper layer and lower layer will be described. It is preferable that the ceramic substrate has a brightness of N4 or less as a value based on the specification of JIS Z 8721. This is because a material having such brightness is excellent in radiant heat and concealing property. Further, such a ceramic substrate can accurately measure the surface temperature by using a thermoviewer.

Here, the lightness N is defined as 0 for an ideal black lightness, 10 for an ideal white lightness, and a brightness of the color between these black lightness and white lightness. Each color is divided into 10 so that the perception of the color becomes a constant rate, and displayed by symbols N0 to N10. And the actual measurement is N0
The comparison is performed with the color chart corresponding to N10. In this case, the first decimal place is 0 or 5.

The ceramic substrate having such characteristics has a carbon content of 100 to 5000 p in the ceramic substrate.
pm. There are two types of carbon, amorphous and crystalline.Amorphous carbon can suppress a decrease in volume resistivity of a ceramic substrate at a high temperature. Since the decrease in thermal conductivity at high temperatures can be suppressed, the type of carbon can be appropriately selected according to the purpose of the substrate to be manufactured.

The amorphous carbon is, for example, C, H, O
Hydrocarbons, preferably saccharides, can be obtained by calcining in air, and graphite powder or the like can be used as the crystalline carbon. In addition, carbon can be obtained by thermally decomposing the acrylic resin under an inert atmosphere and then heating and pressurizing. However, by changing the acid value of the acrylic resin, it is possible to obtain a crystalline (non-crystalline) material. Can be adjusted.

The thickness of the ceramic substrate is 20
mm or less. If the thickness of the ceramic substrate exceeds 20 mm, the heat capacity of the ceramic substrate may be too large, and if the ceramic substrate is heated and cooled, the temperature followability is reduced due to the large heat capacity. Further, its thickness is desirably 0.5 mm or more. When the thickness is smaller than 0.5 mm, the strength of the ceramic substrate itself is reduced, so that the ceramic substrate is easily broken. More preferably, it is more than 1.5 mm and 5 mm or less. When the thickness is more than 5 mm, the heat becomes difficult to propagate, and the heating efficiency tends to decrease. On the other hand, when the thickness is less than 1.5 mm, the heat propagating in the ceramic substrate is not sufficiently diffused, so that the temperature of the heating surface is reduced. This is because variations may occur, and the strength of the ceramic substrate may be reduced to cause breakage.

The ceramic substrate has a diameter of 190.
mm is desirable. Especially 12 inches (300
mm) or more. This is because it will become the mainstream of next-generation silicon wafers. Further, the ceramic substrate is desirably a disk. This is because a circular object to be processed such as a silicon wafer is usually attracted and heated.

In the present invention, a thermocouple can be embedded in the ceramic substrate as required. This is because the temperature of the ceramic substrate (electrostatic chuck) can be measured with a thermocouple, and the voltage and current amount can be changed based on the data to control the temperature.

The size of the junction of the metal wires of the thermocouple is preferably equal to or larger than the element diameter of each metal wire and 0.5 mm or less. With such a configuration, the heat capacity of the junction is reduced, and the temperature is accurately and quickly converted to a current value. For this reason, the temperature controllability is improved and the temperature distribution on the heated surface of the wafer is reduced. Examples of the thermocouple include J
As listed in IS-C-1602 (1980),
K-type, R-type, B-type, S-type, E-type, J-type, and T-type thermocouples are exemplified.

As the electrostatic electrode formed in the electrostatic chuck of the present invention, an electrostatic electrode having a shape as shown in FIG. 2 can be mentioned. Body, metal foil and the like.

As the metal sintered body, tungsten,
Those composed of at least one selected from molybdenum are preferred. Further, it is desirable that the metal foil is also made of the same material as the metal sintered body. This is because these metals are relatively hard to be oxidized and have sufficient conductivity as electrodes.
As the conductive ceramic, at least one selected from carbides of tungsten and molybdenum can be used.

FIGS. 4 and 5 are horizontal sectional views schematically showing electrostatic electrodes in another electrostatic chuck.
In the electrostatic chuck 20 shown in FIG. 5, a semicircular chuck positive electrode electrostatic layer 22 and a chuck negative electrode electrostatic layer 23 are formed inside the ceramic substrate 1, and in the electrostatic chuck shown in FIG. Inside 1 are formed chuck positive electrostatic layers 32a and 32b and chuck negative electrostatic layers 33a and 33b each having a shape obtained by dividing a circle into four parts. Further, the two positive electrode electrostatic layers 22a and 22b and the two chuck negative electrode electrostatic layers 33a and 33b are formed to cross each other. An RF electrode may be provided on the electrostatic chuck. In the case of forming an electrode in which a circular electrode or the like is divided, the number of divisions is not particularly limited, and may be five or more, and the shape is not limited to a sector.

As described above, these electrostatic electrodes are formed in the lower layer of the ceramic substrate. Therefore, a connecting portion (through hole) for connecting these electrostatic electrodes to external terminals is required. This through hole is made of high melting point metal such as tungsten paste, molybdenum paste, etc.
It is formed by filling a conductive ceramic such as tungsten carbide or molybdenum carbide.

The diameter of the through hole is 0.1 to 10
mm is desirable. This is because cracks and distortion can be prevented while preventing disconnection. External terminals are connected using the through holes as connection pads.

The connection is made by solder or brazing material. As brazing materials, silver brazing, palladium brazing, aluminum brazing,
Use gold brazing. As the gold solder, an Au-Ni alloy is desirable. This is because the Au-Ni alloy has excellent adhesion to tungsten.

The ratio of Au / Ni is [81.5-82.
5 (% by weight)] / [18.5 to 17.5 (% by weight)] is desirable. The thickness of the Au—Ni layer is desirably 0.1 to 50 μm. This is because the range is sufficient to secure the connection.
Moreover, 500-1000 at a high vacuum of 10 ^-6 to 10 ^-5 Pa.
When used at high temperature of ℃, Au-Cu alloy deteriorates,
An Au-Ni alloy is advantageous without such deterioration.
The total amount of impurity elements in the Au—Ni alloy is 100%.
It is desirable that the amount be less than 1 part by weight when it is used as a part by weight.

As the resistance heating element formed in the lower layer of the ceramic substrate, double concentric circles as shown in FIG. 3 were formed as one set of circuits to form a single line. In addition to the pattern, for example, a pattern such as a spiral, an eccentric circle, a bent line, etc., can be cited. However, the concentric circle as shown in FIG. Or a combination of concentric circles and bent shapes.

As the material of the resistance heating element, for example, a sintered body of metal or conductive ceramic, metal foil,
Metal wires and the like.

As the metal sintered body, tungsten,
At least one selected from molybdenum is preferred. This is because these metals are relatively hard to oxidize and have a resistance value sufficient to generate heat. The metal particles used in the metal sintered body may be spherical, scaly, or a mixture of spherical and scaly.

As the conductive ceramic, at least one selected from carbides of tungsten and molybdenum can be used.

A metal oxide may be added to the metal sintered body. The reason for using this metal oxide is to bring the ceramic substrate and the metal particles into close contact with each other. Although the reason why the metal oxide improves the adhesion between the ceramic substrate and the metal particles is not clear, the surface of the metal particles has a slight oxide film formed thereon, and the ceramic substrate is formed of an oxide. Of course, even if it is a non-oxide ceramic,
An oxide film is formed on the surface. Therefore, it is considered that this oxide film is sintered and integrated on the surface of the ceramic substrate via the metal oxide, so that the metal particles and the ceramic substrate adhere to each other.

As the metal oxide, for example,
Lead, zinc oxide, silica, boron oxide (B _Two O_Three ), Al
At least one selected from Mina, Yttria and Titania
Species are preferred. These oxides have the resistance value of the resistance heating element.
Between the metal particles and the ceramic substrate without increasing the
This is because adhesion can be improved.

It is desirable that the amount of the metal oxide is 0.1 to less than 10 parts by weight based on 100 parts by weight of the metal particles. By using a metal oxide in this range,
This is because the resistance value does not become too large and the adhesion between the metal particles and the ceramic substrate can be improved.

The ratios of lead oxide, zinc oxide, silica, boron oxide (B ₂ O ₃ ), alumina, yttria, and titania are such that when the total amount of metal oxide is 100 parts by weight, 10 parts by weight, 1 to 30 parts by weight of silica, 5 to 50 parts by weight of boron oxide, 20 to 7 parts of zinc oxide
0 parts by weight, alumina 1 to 10 parts by weight, yttria 1
-50 parts by weight and titania of 1-50 parts by weight are preferred.
However, it is desirable that the total be adjusted so that the total does not exceed 100 parts by weight. This is because these ranges can particularly improve the adhesion to the ceramic substrate.

As the above-mentioned metal foil, for example, it is desirable to use a nickel foil, a stainless steel foil or the like as a resistance heating element by patterning it by etching or the like. Examples of the metal wire include a tungsten wire and a molybdenum wire. The above patterned metal foils may be bonded together with a resin film or the like.

The resistance heating element may be provided in a plurality of layers.
In this case, it is desirable that the patterns of the respective layers are formed so as to complement each other, and that the pattern is formed on any layer when viewed from the heating surface. For example, the structure is a staggered arrangement.

Further, it is desirable that the resistance heating element is provided within a range of 60% of the thickness from the bottom surface of the ceramic substrate. This is because heat is diffused before reaching the heating surface, and the temperature of the heating surface tends to be uniform.

The resistance heating element preferably has a thickness of about 1 to 50 μm and a width of about 5 to 20 μm. The resistance heating element may have a rectangular or elliptical cross section, but is preferably flat. This is because the flat surface is more likely to dissipate heat toward the heating surface, so that the temperature distribution on the heating surface is less likely to occur.
The aspect ratio of the cross section of the resistance heating element (the width of the resistance heating element / the thickness of the resistance heating element) is desirably 200 to 5,000.

Further, since the resistance heating element is formed in the lower layer of the ceramic substrate, it is necessary to provide a through hole for connecting to an external terminal as in the case of the above-mentioned electrostatic electrode. This through hole may be the same as the through hole for connecting the electrostatic electrode described above.

Further, the resistance heating element may be formed on the bottom surface of the ceramic substrate. In this case, a conductor paste for a resistance heating element containing metal particles or the like as described above is applied to the bottom surface of the ceramic substrate to form a conductor paste layer of a predetermined pattern, which is then baked, and the metal paste is applied to the bottom surface of the ceramic substrate. A method of sintering particles or the like is preferred. The sintering of the metal is sufficient if the metal particles and the metal particles and the ceramic are fused.

The conductive paste is not particularly limited, but preferably contains not only the above-mentioned metal particles or conductive ceramic but also a resin, a solvent, a thickener and the like.

Examples of the resin include an epoxy resin and a phenol resin. Examples of the solvent include isopropyl alcohol. Examples of the thickener include cellulose and the like.

When the resistance heating element is formed on the bottom surface of the ceramic substrate, the thickness of the resistance heating element is preferably 1 to 30 μm, more preferably 1 to 10 μm. Further, the width is preferably 0.1 to 20 mm, more preferably 0.1 to 5 mm.

The aspect ratio is 10 to 200.
It is desirable that This aspect ratio is larger when the resistance heating element is formed on the bottom surface of the ceramic substrate than when the resistance heating element is formed inside the ceramic substrate. This is because the distance between the heating surface and the resistance heating element is shortened and the temperature uniformity of the surface is reduced, so that it is necessary to flatten the resistance heating element itself. Further, it is desirable that the surface of such a resistance heating element is covered with a metal coating layer. This is for preventing the surface of the resistance heating element from being oxidized to change the resistance value.

The temperature control means in the electrostatic chuck of the present invention includes, for example, a Peltier element in addition to the above-described resistance heating element.

When a Peltier element is used as the temperature control means, heat is generated by changing the direction of current flow.
This is advantageous because both cooling can be performed. The Peltier element is formed by connecting p-type and n-type thermoelectric elements in series and joining them to a ceramic substrate or the like.
Examples of the Peltier element include a silicon-germanium-based material, a bismuth-antimony-based material, and a lead / tellurium-based material.

FIG. 6 is a cross-sectional view schematically showing an example of a supporting container for disposing the electrostatic chuck of the present invention having the above-described structure. The support container 41 includes the electrostatic chuck 1
01 is fitted through the heat insulating material 45. Further, the support container 41 has a refrigerant outlet 42.
Is formed, and the refrigerant is blown from the refrigerant injection port 44 and goes out of the suction port 43 through the refrigerant discharge port 42, and the electrostatic chuck 101 is cooled by the action of the refrigerant. You can do it. Further, the support container 41 may be configured such that, after the electrostatic chuck 101 is mounted on the upper surface of the support container 41, the support container 41 is fixed with a fixing member such as a bolt.

The electrostatic chuck of the present invention, which is one embodiment of the ceramic substrate of the present invention, has been described above. However, in the ceramic substrate for a semiconductor manufacturing / inspection apparatus of the present invention, the conductor formed therein has resistance heating. When only the body is used, the ceramic substrate functions as a ceramic heater. FIG. 7 is a bottom view schematically showing a ceramic heater which is an example of the ceramic substrate for a semiconductor manufacturing / inspection apparatus of the present invention, and FIG. 8 is a schematic view showing a part of the ceramic heater shown in FIG. FIG. 3 is a partially enlarged cross-sectional view shown.

As shown in FIG. 7, the ceramic heater 2
01 is formed in a disk shape, while inside the ceramic substrate 110,
A plurality of resistance heating elements 15 are formed, and the arrangement of these circuits is designed so that the temperature on the heating surface 110a becomes uniform.

As shown in FIG. 8, the ceramic substrate 110 has an upper layer 108 exhibiting the property of intragranular fracture at the time of destruction and a lower layer 108 exhibiting the property of intergranular fracture at the time of destruction. 109.

A through hole 27 is provided directly below the end of the resistance heating element 15, and a blind hole is formed so that the through hole 27 is exposed to the outside. 23, and the external terminal 23 is
The connection between the resistance heating element 15 and a power supply or the like can be established through the connection 7. Although not shown in FIG. 8, a socket or the like provided with wiring is connected to the external terminal 23 to connect to a power supply or the like.

A bottomed hole 21 for inserting a temperature measuring element is formed in the ceramic substrate 110, and a through hole 22 for inserting a lifter pin 26 is formed in a portion near the center. ing.

The lifter pins 26 can place the silicon wafer 19 on the lifter pin 26 and move it up and down. Wafer 19
Can be received, and the silicon wafer 19 can be placed on the heating surface 110 a of the ceramic substrate 110 and heated, or the silicon wafer 19 can be heated
It can be supported and heated at a distance of 50 to 2000 μm from “a”.

Further, a through hole or a concave portion is provided in the ceramic substrate 110, and a lifter pin or a support pin having a spire or a hemispherical tip is inserted into the through hole or the concave portion. By fixing the silicon wafer 19 with the lifter pins and the support pins slightly protruding, the heating surface 1
The heating may be performed in a state of being separated from 10a by 50 to 2000 μm.

In the ceramic heater 201, the upper layer 1
Reference numeral 08 denotes a layer having a structure exhibiting the property of intra-particle destruction at the time of destruction. Since the particles constituting this layer are firmly bonded to each other, the ceramic particles do not fall off from the heating surface, and the particles from the upper layer 108 Is dropped and adheres to an object to be processed such as the silicon wafer 19 or the silicon wafer 1
9 and the heating surface 110 of the ceramic substrate 110
a can be prevented. On the other hand, lower layer 1
The reference numeral 09 indicates that (the layer including the resistance heating element 15 and its vicinity, and the layer below the resistance heating element 15) exhibit the property of grain boundary destruction at the time of destruction, and the ratio of pores is small. A short circuit between them can be prevented. When an RF electrode is present, the RF electrode is also formed in the lower layer 109, and a short circuit between the resistance heating element 15 and the RF electrode can be prevented.

Further, on the surface of the ceramic substrate of the present invention,
When a chuck top conductor layer is formed, a conductor layer formed inside the ceramic substrate is a guard electrode, and a ground electrode is formed as another conductor layer further below the guard electrode, the ceramic substrate is replaced with a wafer prober. Function as a ceramic plate.

Also in this case, by forming the upper portion of the ceramic substrate as a layer having a structure of exhibiting the property of intra-particle destruction at the time of destruction, the ceramic particles do not fall off from the surface and adhere to the object to be processed. It is possible to prevent poor adhesion between the object to be processed and the heating surface of the ceramic substrate, and to form a layer including a structure including the chuck top conductor layer, the guard electrode, and the ground electrode so as to exhibit grain boundary destruction when broken. By doing so, a short circuit between the chuck top conductor layer, the guard electrode and the ground electrode, and a short circuit between the horizontally adjacent conductor layers can be prevented.

Next, an example of the method of manufacturing the electrostatic chuck according to the present invention will be described with reference to the sectional views shown in FIGS. (1) First, a ceramic powder such as a nitride ceramic or a carbide ceramic is mixed with a binder and a solvent to obtain a green sheet 55 for the upper layer and a green sheet 50 for the lower layer. For the ceramic powder for the upper layer, use a sintering aid such as yttria or carbon at the above ratio, or use an aluminum nitride powder containing oxygen obtained by firing in an oxidizing atmosphere. can do. Further, a sintering aid such as yttria or carbon is added to the lower layer ceramic powder in the above-described ratio.

The lower-layer green sheet 50 and the upper-layer green sheet 55, which are laminated immediately above the green sheet 50 on which the electrostatic electrode layer printed body 51 to be described later is formed, are formed by a layer which becomes the ceramic dielectric film 4. It is.

The binder is preferably at least one selected from an acrylic binder, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol.
Further, as the solvent, at least one selected from α-terpineol and glycol is desirable. The paste obtained by mixing these is formed into a sheet shape by a doctor blade method or the like to produce green sheets 50 and 55.

If necessary, the green sheet 50 may be provided with a through hole for inserting a support pin of a silicon wafer, a concave portion for embedding a thermocouple, a portion for forming a through hole, and the like. The through holes can be formed by punching or the like. The thickness of the green sheet 50 is preferably about 0.1 to 5 mm.

Next, a conductive paste is filled into the through holes of the green sheet 50 to form through-hole prints 53 and 54. Next, a conductor serving as an electrostatic electrode layer or a resistance heating element is formed on the green sheet 50. Print the paste. The printing is performed so as to obtain a desired aspect ratio in consideration of the shrinkage ratio of the green sheet 50.
1. The resistance heating element layer printed body 52 is obtained. The printed body is formed by printing a conductive paste containing conductive ceramic, metal particles, and the like.

As the conductive ceramic particles contained in these conductor pastes, carbides of tungsten or molybdenum are most suitable. This is because it is hard to be oxidized and the thermal conductivity is hard to decrease. Further, as the metal particles, for example, tungsten, molybdenum, platinum, nickel and the like can be used.

The average particle size of the conductive ceramic particles and metal particles is preferably 0.1 to 5 μm. This is because it is difficult for these particles to print the conductor paste even if they are too large or too small. As such a conductive paste, 85 to 97 parts by weight of metal particles or conductive ceramic particles, 1.5 to 10 parts by weight of at least one binder selected from acrylic, ethyl cellulose, butyl cellosolve and polyvinyl alcohol, α-terpineol, Optimally, a mixture prepared by mixing 1.5 to 10 parts by weight of at least one solvent selected from glycol, ethyl alcohol and butanol.

Next, as shown in FIG. 9 (a), a green sheet 50 having printed materials 51, 52, 53, 54 for the lower layer, a green sheet 50 having no printed material, and a green sheet 50 for the upper layer. The sheet 55 is laminated. The reason why the green sheet 50 having no printed body is laminated on the side where the resistance heating element is formed is to prevent the end face of the through hole from being exposed and being oxidized during firing for forming the resistance heating element. . If baking for forming the resistance heating element is performed while the end face of the through hole is exposed, it is necessary to sputter a hardly oxidizable metal such as nickel, and more preferably, to coat with Au-Ni gold solder. Is also good.

(2) Next, as shown in FIG.
The laminate is heated and pressed to sinter the green sheet and the conductive paste. The heating temperature is 1600-1
800 ° C, pressurization is 10-20MPa (100-200k
g / cm ² ), and these heating and pressurizing are
Performed under an inert gas atmosphere. As the inert gas, argon, nitrogen, or the like can be used. In this process,
Through holes 16 and 17, chuck positive electrode electrostatic layer 2, chuck negative electrode electrostatic layer 3, resistance heating element 5 and the like are formed.

(3) Next, as shown in FIG.
Bag holes 35 and 36 for connecting external terminals are provided. Blind hole 3
At least a part of the inner wall of each of 5, 5 and 36 is made conductive, and the conductive inner wall is connected to chuck positive electrostatic layer 2, chuck negative electrostatic layer 3, resistance heating element 5, and the like. desirable.

(4) Finally, as shown in FIG. 9D, external terminals 6 and 18 are provided in the blind holes 35 and 36 via a solder layer (not shown). Furthermore, if necessary, a bottomed hole can be provided, and a thermocouple can be embedded therein. As the solder, alloys such as silver-lead, lead-tin, and bismuth-tin can be used. The thickness of the solder layer is 0.1 to
50 μm is desirable. This is because the range is sufficient to secure the connection by soldering. Further, the connection of the external terminals 6 and 18 may be performed by using a brazing solder.

A conductor is provided on the surface and inside of the ceramic substrate for a semiconductor manufacturing / inspection apparatus of the present invention, the conductor layer on the surface is a chuck top conductor layer, and the conductor inside is either a guard electrode or a ground electrode. In at least one case, the ceramic substrate functions as a wafer prober. When the conductor near the upper surface is not provided, the dielectric film is not provided, and the conductor is formed as a heating element, the ceramic substrate of the present invention functions as a hot plate.

[0105]

The present invention will be described in more detail below. Example 1 Production of Electrostatic Chuck (See FIG. 9) (1) As a green sheet for the upper layer, 100 parts by weight of aluminum nitride powder (average particle size: 0.6 μm), yttria (average particle size: 0.1 μm). Using a paste obtained by mixing 0.3 parts by weight, 12 parts by weight of an acrylic binder, and alcohol by a doctor blade method, a green sheet 51 having a thickness of 0.47 mm was obtained. Also, as a green sheet for the lower layer, 1000 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size: 0.2 μm), 40 parts by weight of yttria (average particle size: 0.4 μm),
Acrylic binder 115 parts by weight, boron nitride 0.002
Using a paste obtained by mixing 5 parts by weight, 5 parts by weight of a dispersant, and 530 parts by weight of alcohol composed of 1-butanol and ethanol, molding by a doctor blade method was performed.
A green sheet 50 having a thickness of 0.47 mm was obtained.

(2) Next, the green sheet is heated to 80 ° C.
After drying for 5 hours, punch 1.8m in diameter
A portion serving as a through hole for inserting a semiconductor wafer support pin having a length of 3.0 mm and 5.0 mm, and a portion serving as a through hole for connecting to an external terminal were provided.

(3) 100 parts by weight of tungsten carbide particles having an average particle diameter of 1 μm, acrylic binder 3.0
By weight, 3.5 parts by weight of the α-terpineol solvent and 0.3 parts by weight of the dispersant were mixed to prepare a conductor paste A. A conductive paste B was prepared by mixing 100 parts by weight of tungsten particles having an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of an α-terpineol solvent, and 0.2 parts by weight of a dispersant. This conductive paste A
Was printed on the lower layer green sheet 50 by screen printing to form a conductor paste layer. The printing pattern was a concentric pattern. Also, another lower layer green sheet 5
At 0, a conductive paste layer composed of an electrostatic electrode pattern having the shape shown in FIG.

Further, the conductive paste B was filled in through holes for through holes for connecting external terminals. On the green sheet for lower layer 50 after the above treatment, 34 green sheets for lower layer 50 on which the tungsten paste is not printed are further laminated on the upper side (heating surface) and 13 on the lower side.
A lower layer green sheet 50 on which a conductor paste layer composed of an electrostatic electrode pattern is printed is laminated thereon, and a lower layer green sheet 50 on which a tungsten paste is not printed is further laminated thereon, and further thereon. Then, an upper layer green sheet was laminated. These are 130 ° C, 8MP
a (80 kg / cm ² ) to form a laminate (FIG. 7A).

(4) Next, the obtained laminate was degreased in a nitrogen gas at 600 ° C. for 5 hours, and hot pressed for 3 hours.
The test was performed at 700 ° C. under a pressure of 20 MPa (200 kg / cm ² ) to obtain a 3 mm-thick aluminum nitride plate. This was cut out into a 230 mm disk shape, and a 6 μm thick, 10 mm wide resistance heating element 5 and a 10 mm thick
A plate made of aluminum nitride having a chuck positive electrode electrostatic layer 2 and a chuck negative electrode electrostatic layer 3 of μm (FIG. 7)
(B)).

(5) Next, the plate obtained in (4) is
After polishing with a diamond grindstone, a mask is placed and Si
A bottomed hole (diameter: 1.2 mm, depth: 2.0 mm) for a thermocouple was provided on the surface by blasting treatment with C or the like.

(6) Further, the portions where the through holes are formed are cut out to form blind holes 35 and 36 (FIG. 7).
(C)) Using a gold solder made of Ni-Au in the blind holes 35 and 36, the external terminals 6 and 18 made of Kovar were connected by heating and reflowing at 700 ° C. (FIG. 7D). In addition,
The connection of the external terminals is preferably a structure in which a tungsten support is supported at three points. This is because connection reliability can be ensured.

(7) Next, a plurality of thermocouples for temperature control were embedded in the bottomed holes, and the manufacture of the electrostatic chuck having the resistance heating element was completed.

Example 2 Production of Electrostatic Chuck (See FIG. 9) As a green sheet for the upper layer, 100 parts by weight of aluminum nitride powder (average particle size: 0.6 μm, manufactured by Tokuyama Corporation) and yttria (average particle size: 0.4 μm) Molded by a doctor blade method using a paste obtained by mixing 0.2 parts by weight, 11.5 parts by weight of an acrylic binder, 0.5 parts by weight of a dispersant, and 53 parts by weight of alcohol composed of 1-butanol and ethanol. Was performed to obtain a green sheet having a thickness of 0.47 mm, except that an electrostatic chuck was manufactured in the same manner as in Example 1.

Example 3 Production of Electrostatic Chuck (See FIG. 9) 1000 parts by weight of aluminum nitride powder (manufactured by Tokuyama Co., average particle size 0.6 μm) and yttria (average particle size: 0.4 μm) 40 parts by weight,
Acrylic binder 115 parts by weight, boron nitride 0.002
Parts by weight, silica 0.05 parts by weight, Na ₂ O: 0.001
Using a paste obtained by mixing 5 parts by weight, 5 parts by weight of a dispersant, and 530 parts by weight of alcohol composed of 1-butanol and ethanol, molding by a doctor blade method was performed.
An electrostatic chuck was manufactured in the same manner as in Example 1, except that a green sheet having a thickness of 0.47 mm was obtained.

Example 4 Production of Electrostatic Chuck (See FIG. 9) As a green sheet for the upper layer, 100 parts by weight of aluminum nitride powder (average particle size: 0.6 μm, manufactured by Tokuyama Corporation) and yttria (average particle size: 0.4 μm) Molded by a doctor blade method using a paste obtained by mixing 0.2 parts by weight, 11.5 parts by weight of an acrylic binder, 0.5 parts by weight of a dispersant, and 53 parts by weight of alcohol composed of 1-butanol and ethanol. Was performed to obtain a green sheet having a thickness of 0.47 mm, and an electrostatic chuck was manufactured in the same manner as in Example 3.

Comparative Example 1 Production of Electrostatic Chuck (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), yttria (average particle size:
0.4 μm) Using a paste obtained by mixing 4 parts by weight, 11.5 parts by weight of an acrylic binder, 0.5 parts by weight of a dispersant, and 53 parts by weight of alcohol composed of 1-butanol and ethanol, molding is performed by a doctor blade method. Thus, a green sheet having a thickness of 0.47 mm was obtained.

(2) Next, the green sheet is heated to 80 ° C.
After drying for 5 hours, punch 1.8m in diameter
A portion serving as a through hole for inserting a semiconductor wafer support pin having a length of 3.0 mm and 5.0 mm, and a portion serving as a through hole for connecting to an external terminal were provided.

(3) 100 parts by weight of tungsten carbide particles having an average particle diameter of 1 μm, acrylic binder 3.0
By weight, 3.5 parts by weight of the α-terpineol solvent and 0.3 parts by weight of the dispersant were mixed to prepare a conductor paste A. A conductive paste B was prepared by mixing 100 parts by weight of tungsten particles having an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of an α-terpineol solvent, and 0.2 parts by weight of a dispersant. This conductive paste A
Was printed on a green sheet by screen printing to form a conductor paste layer. The printing pattern was a concentric pattern. Further, a conductor paste layer composed of an electrostatic electrode pattern having the shape shown in FIG. 4 was formed on another green sheet.

Further, the conductive paste B was filled in through holes for through holes for connecting external terminals. On top of the green sheet after the above processing, a green sheet on which the tungsten paste is not printed is placed on the upper side (heating surface).
34 sheets, 13 sheets on the lower side, a green sheet on which a conductive paste layer composed of an electrostatic electrode pattern is printed, and two green sheets on which no tungsten paste is printed are further stacked thereon. And these are 13
The laminate was formed by pressure bonding at 0 ° C. and a pressure of 8 MPa (80 kg / cm ² ).

(4) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and at 1890 ° C. under a pressure of 15 M
Hot press for 3 hours at Pa (150kg / cm ² )
An aluminum nitride plate having a thickness of 3 mm was obtained. This is 2
Cut out into a 30mm disk shape, 6μm thick, 1 width inside
A plate made of aluminum nitride having a resistance heating element 5 of 0 mm, a chuck positive electrostatic layer 2 and a chuck negative electrostatic layer 3 of 10 μm thickness was used.

(5) Next, the plate obtained in (4) is
After polishing with a diamond grindstone, a mask is placed and Si
A bottomed hole (diameter: 1.2 mm, depth: 2.0 mm) for a thermocouple was provided on the surface by blasting treatment with C or the like.

(6) Further, a portion in which the through hole is formed is cut out to form a blind hole, and Ni-A
An external terminal made of Kovar was connected by heating and reflowing at 700 ° C. using a gold solder made of u.

(7) Next, a plurality of thermocouples for temperature control were embedded in the bottomed holes, and the manufacture of the electrostatic chuck having the resistance heating element was completed.

Comparative Example 2 Production of Electrostatic Chuck Aluminum Nitride Powder (Average Particle Size: 0.6 μm) 100
Using a paste obtained by mixing 0.3 parts by weight of yttria (average particle size: 0.4 μm), 12 parts by weight of an acrylic binder, and alcohol, a green sheet having a thickness of 0.47 mm is formed by a doctor blade method. And a pressure of 20 MPa (200 kg / cm)
An electrostatic chuck was manufactured in the same manner as in Comparative Example 1, except that hot pressing was performed for 3 hours under the condition ² ).

With respect to the electrostatic chucks manufactured in Examples 1 to 4 and Comparative Examples 1 and 2, the number of particles, observation of a broken section, measurement of porosity, and temperature distribution after heating the ceramic substrate to 400 ° C. A measurement and an insulation test of the conductor circuit in the ceramic substrate were performed to confirm whether or not a short circuit occurred between the conductor circuits. The results are shown in Table 1 below.

[0126]Evaluation method  (1) Measurement of the number of particles A silicon wafer is placed and 50 kg / cm^Two The load of
Observation of any 10 locations on the silicon wafer with an electron microscope
Measurement and counting the number of particles with a particle diameter of 2 μm or more.
It was divided by the shadow field area.

(2) Observation of state of fracture section The fracture section was observed under an electron microscope at a magnification of 5000, and it was confirmed whether or not it was intraparticle fracture. FIG. 10 is a scanning electron microscope (SEM) photograph of a fracture cross section near the upper surface (upper layer) of the electrostatic chuck according to the first embodiment. FIG. 11 is a fracture cross section of a lower layer of the electrostatic chuck according to the first embodiment. A scanning electron microscope (SEM) photograph was shown.

(3) Measurement of Temperature Difference on Heating Surface The electrostatic chucks according to Examples 1 to 4 and Comparative Examples 1 and 2 were energized to raise the temperature of the electrostatic chuck to 400 ° C. Was measured with a thermoviewer (IR162012-0012, manufactured by Nippon Datum).

(4) Insulation Test of Conductor Circuit in Ceramic Substrate It was confirmed using a tester whether or not insulation was maintained between the conductor circuits provided in the ceramic substrate, and whether or not a short circuit occurred. .

(5) Measurement of Porosity The porosity was measured by the Archimedes method. In the measurement of the pore diameter of the upper layer of the electrostatic chuck, the upper layer was thinly peeled off.

[0131]

[Table 1]

As is clear from the results shown in Table 1, near the upper surface (upper layer) of the electrostatic chucks according to Examples 1 to 4.
The fractured cross section of the specimen exhibited the property of intra-particle fracture. Therefore, the number of particles observed near the surface of the object to be processed such as a silicon wafer was small. On the other hand, the fracture section of the lower part (lower layer) exhibited the property of grain boundary fracture. The porosity was lower in the lower layer than in the upper layer. Therefore, the results of the insulation tests of the conductor circuits in the ceramic substrate were all good, and no short circuit occurred.

On the other hand, in Comparative Example 1, the fractured cross section exhibited the property of grain boundary fracture in both the upper layer and the lower layer. In this comparative example, the porosity is small in the entire ceramic substrate,
The result of the insulation test of the conductor circuit in the ceramic substrate was good, and no short circuit occurred between the conductor circuits.However, the number of particles observed on the surface of the object to be processed such as a silicon wafer was large. In the conductor circuit of the wafer,
Short circuit, disconnection, etc. have occurred. Further, the fracture cross section of the electrostatic chuck according to Comparative Example 2 exhibits the property of intra-particle destruction in both the upper layer and the lower layer. Therefore, the number of particles observed on the surface of the object to be processed such as a silicon wafer is small, and No short circuit, disconnection, etc. occurred in the conductor circuit of Example 1, but the porosity was high as a whole, insulation between the conductor circuits in the ceramic substrate was not maintained, and a short circuit occurred.

[0134]

As described above, the ceramic substrate for a semiconductor manufacturing / inspection apparatus according to the present invention is a ceramic substrate having a conductor formed therein, the ceramic layer including the conductor and being below the conductor. The (lower layer) exhibits the property of grain boundary fracture at the time of fracture, and the other ceramic layers (upper layer)
It is characterized by the fact that it exhibits the property of intra-particle destruction at the time of destruction, so that particles due to falling of ceramic particles are hardly generated on the surface of the substrate on which the object to be processed is mounted.
Short circuits, disconnections, and the like are less likely to occur in the conductor circuits formed on the workpiece (silicon wafer). In addition, since the porosity existing between the conductor circuits in the ceramic substrate is small, short circuit does not occur between the conductor circuits, and it can function well.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of the electrostatic chuck of the present invention.

FIG. 2 is a sectional view taken along line AA of the electrostatic chuck shown in FIG.

FIG. 3 is a sectional view taken along line BB of the electrostatic chuck shown in FIG. 1;

FIG. 4 is a cross-sectional view schematically showing one example of the electrostatic chuck of the present invention.

FIG. 5 is a cross-sectional view schematically showing one example of the electrostatic chuck of the present invention.

FIG. 6 is a cross-sectional view schematically showing a state where the electrostatic chuck of the present invention is fitted into a support container.

FIG. 7 is a bottom view schematically showing an example of a ceramic heater using the ceramic substrate for a semiconductor manufacturing / inspection apparatus of the present invention.

FIG. 8 is a partially enlarged sectional view showing a part of the ceramic heater shown in FIG. 7;

FIGS. 9A to 9D are cross-sectional views schematically showing a part of the manufacturing process of the electrostatic chuck.

FIG. 10 is a scanning electron microscope (SEM) photograph showing a fracture cross section near the upper surface (upper layer) of the electrostatic chuck according to Example 1.

FIG. 11 is a scanning electron microscope (SEM) photograph showing a fracture cross section of a lower layer of the electrostatic chuck according to Example 1.

[Explanation of symbols]

 Reference Signs List 1, 110 Ceramic substrate 2, 22, 32a, 32b Chuck positive electrode layer 3, 23, 33a, 33b Chuck negative electrode layer 2a, 3a Semicircular portion 2b, 3b Comb portion 4 Ceramic dielectric film 5, 15 Resistance heating element 6, 13, 18, 23 External terminal 9, 19 Silicon wafer 14, 21, Bottom hole 15, 22, Through hole 16, 17, 27 Through hole 20, 30, 101 Electrostatic chuck 41 Support container 42 Refrigerant outlet 43 suction port 44 refrigerant injection port 45 heat insulating material 201 ceramic heater

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 3/18 H05B 3/20 328 3/20 328 C04B 35/58 104Y F-term (Reference) 3K034 AA02 AA04 AA15 AA16 AA34 BA06 BB06 BC03 BC16 BC17 HA01 HA10 JA02 JA10 3K092 PP20 QA05 QB02 QB03 QB30 QB31 QB70 RF03 RF11 RF17 RF26 RF27 VV40 4G001 BA09 BA36 BB09 BB36 BC13 BC31 BC32 BC35 BC42 BC54 BC73 HA38 HA38 HA38

Claims (2)

[Claims] 1. A ceramic substrate having a conductor formed therein, wherein a ceramic layer including the conductor and the vicinity thereof, and a ceramic layer below the conductor exhibit a property of grain boundary destruction when broken. Other ceramic layers
A ceramic substrate for a semiconductor manufacturing / inspection apparatus, which exhibits a property of intra-particle destruction at the time of destruction. 2. An electrostatic chuck in which an electrostatic electrode and a resistance heating element are formed inside a ceramic substrate, wherein the ceramic layer includes the electrostatic electrode and its vicinity, and a ceramic layer below the electrostatic electrode. An electrostatic chuck, wherein the layer exhibits a property of intergranular fracture when broken, and the other ceramic layer exhibits a property of intragranular fracture when broken.