JP2001077182A - Ceramic substrate for manufacturing and checking semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a superior temperature rise and fall characteristic or an attraction characteristic by a method wherein in the interior of an insulation ceramic substrate composed of nitride ceramic, carbide, ceramic, or oxide ceramic, a plate-like conductor forming a flat shape of a specified sectional aspect ratio is buried. SOLUTION: Nitride ceramic, carbide ceramic, or oxide ceramic is used as a material of a ceramic substrate 1 because it is smaller in thermal expansion coefficient than a metal, and even if thinned, it is not warped or distorted by heating, its thermal conductivity is high, and surface temperatures of the ceramic substrate are easy to respond promptly to a temperature change of a heating unit 2. In a ceramic heater, the plate-like heating unit of a flat sectional shape is buried in the interior of the substrate. The heating unit 2 has a flat shape in the range of 10 to 5000 in a sectional aspect ratio (a width of the heating unit/a thickness of the heating unit), and indicates a temperature distribution analogous to a shape of the heating unit if less than 10, and cannot ensure uniformity of temperatures due to a generation of the biased temperature distribution if exceeding 10,000.

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 for an apparatus for manufacturing and inspecting semiconductor products, and more particularly to a hot plate (heater), a susceptor, an electrostatic chuck, and a wafer prober used for drying semiconductor products. It is a proposal about a ceramic substrate useful for the above.

[0002]

2. Description of the Related Art Generally, an integrated circuit or the like formed on an IC which is a semiconductor product is formed by applying a photosensitive resin as an etching resist on a silicon wafer and then etching it. In this case,
Since the photosensitive resin applied to the surface of the silicon wafer is applied by a spin coater or the like in a manufacturing process, it needs to be dried after the application. The drying process is performed by placing a silicon wafer coated with a photosensitive resin on a hot plate and heating it. Conventionally, such a hot plate, that is, a heater, has a surface of a substrate made of a metal plate (aluminum plate).
(Back surface) with a heating element wired is used.

[0003]

However, when such a metal heater is used for drying a semiconductor product, there are the following problems. That is, since the substrate of the heater is made of metal, the thickness of the substrate must be increased to 15 mm or more. Because on thin metal substrates,
This is because warping or distortion occurs due to thermal expansion caused by heating, and the wafer mounted on the substrate is damaged or tilted. In short, the conventional heater has a problem that it is heavy and bulky due to its thickness.

Further, when the heating temperature of the heater is controlled by changing the voltage or current applied to the heating element attached to the substrate, if the thickness of the substrate is large, the temperature of the heater substrate may fluctuate in the voltage or current. However, there is also a problem that it is difficult to control the temperature of the substrate without quickly following the above.

On the other hand, conventionally, as a method of overcoming the above-mentioned problems, Patent Registration No. 27
Japanese Patent Publication No. 98570 (JP-A-6-177231) and Japanese Patent Publication No. 7-50736 propose a heater in which a spiral linear heating element is embedded in an aluminum nitride electrostatic chuck. However, when such a heater was actually prototyped, it was found that a biased temperature distribution, in which the pattern of the heating element was projected as it was, on the work surface (heating surface) on which the wafer was placed and heated. Was. In particular, this phenomenon is noticeable in a case where an electrostatic chuck electrode serving as a buffer material for dispersing heat of a heater is not embedded in the heater substrate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a ceramic substrate for a semiconductor manufacturing / inspection apparatus which is excellent in temperature rise / fall characteristics and adsorption characteristics and is suitably used as a heater, a susceptor, an electrostatic chuck or a wafer prober. Another object of the present invention is to provide a ceramic substrate capable of promptly and effectively reflecting the function of a buried conductor (heating element or electrode) on a substrate working surface.

[0007]

As a result of continuing studies on the above-mentioned problems, it has been found that the following means are effective for solving the problems. That is, according to the present invention, an insulating ceramic substrate made of a nitride ceramic, a carbide ceramic or an oxide ceramic has a cross-sectional aspect ratio (conductor width / conductor thickness) of 10 to 10.
The present invention proposes a ceramic substrate for a semiconductor manufacturing / inspection apparatus in which 10,000 flat conductors having a flat shape are embedded.

The conductor has a cross-sectional aspect ratio of 50.
It is preferably about 5,000 to 5,000, and more preferably 100 to 3,000. It is preferable that the conductor is formed so as to be embedded at a position deviated in the thickness direction from the center of the thickness of the ceramic substrate, and that a surface far from the embedded conductor is used as a work surface. In the present invention, the conductor is a heating element for a heater or a susceptor,
Electrodes for an electrostatic chuck and a wafer prober are preferable.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A ceramic substrate according to the present invention is used as a substrate for a susceptor, an electrostatic chuck and a wafer prober in addition to a hot plate, that is, a heater. An example will be described.

In the ceramic heater, a ceramic plate, that is, a ceramic substrate is made of an insulating nitride ceramic, carbide ceramic, or oxide ceramic.
It is characterized in that a flat plate-shaped conductor of 0 to 10000, for example, a heater is buried in the case of a heater.

In the present invention, the reason for focusing on nitride ceramics, carbide ceramics or oxide ceramics as the material of the ceramic substrate is that these ceramics have a smaller coefficient of thermal expansion than metal, and even when thin, they warp due to heating. It does not warp or distort. as a result,
According to the present invention, the substrate can be made thin and light.
In addition, since ceramic substrates manufactured from such materials have high thermal conductivity and are thin, the surface temperature of the ceramic substrate tends to quickly respond to changes in the temperature of the heating element. is there. That is, when the voltage and the current of the heating element buried in the ceramic substrate are changed, the changes are promptly expressed as a temperature change of the substrate heating surface, so that it can be said that the temperature control characteristics are excellent.

The nitride ceramic is preferably a metal nitride ceramic, for example, at least one selected from aluminum nitride, silicon nitride, boron nitride and titanium nitride. The carbide ceramic is preferably a metal carbide ceramic, for example, at least one selected from silicon carbide, zirconium carbide, titanium carbide, tantalum carbide, and tungsten carbide. Of these ceramics, aluminum nitride is most preferred. This is because the thermal conductivity is the highest at 180 W / m · K. In addition, as the oxide ceramic, it is desirable to use at least one selected from alumina, silica, mullite, titania, magnesia, and cordierite.

Next, in such a ceramic heater, a plate-like heating element having a flat cross section is embedded in the substrate, and the embedded position is offset from the center of the substrate in the thickness direction (eccentric position). ) And the surface that is farther from the heating element and is farther from the heating element is used as the working surface, that is, the heating surface. Is not projected as it is and an uneven temperature distribution does not occur. That is, the temperature distribution on the heating surface can be made uniform over the entire surface. That is, it is desirable that the position is more than 50% and up to 99% from one surface (heating surface) of the substrate. If it is less than 50%, the temperature distribution is too close to the heating surface and a temperature distribution similar to the pattern of the heating element 2 is generated. Conversely, if it exceeds 99%, the substrate 1 warps and damages the wafer. Because.

The heating element has a flat shape having a cross-sectional aspect ratio (width of the heating element / thickness of the heating element) in the range of 10 to 5000. There is a characteristic that the temperature distribution on the heating surface is easier to be uniform than that having a shape close to a square.
That is, when the cross-sectional aspect ratio of the heating element is less than 10, the heat propagation from the heating element upward (toward the wafer heating surface) is relatively large in the side direction (to the side of the ceramic substrate). As a result, the temperature distribution becomes similar to the shape of the heating element. On the other hand, when the aspect ratio is 1000
If it exceeds 0, heat accumulates near the center of the heating element, which also produces a biased temperature distribution, making it impossible to ensure uniform temperature.

A more preferred aspect ratio is 50 to 500.
0. That is, when the aspect ratio is less than 50, the heating element tends to be a starting point of cracks. On the other hand, when the aspect ratio is more than 5000, sintering between green sheets during production is hindered and an interface is formed between the green sheets. This is because cracks occur. In the case of a heating element having such an aspect ratio, the heating element works effectively even when the impact resistance temperature ΔT (the temperature at which cracking or peeling occurs when dropped into water) of the ceramic substrate is set to 150 ° C. or more.

The arrangement of the heating element 2 is specifically shown in FIGS.
As shown in FIG. 2, in order to make the temperature of the entire ceramic substrate 1 uniform, it is preferable to form a concentric pattern. Further, it is preferable that the thickness of the heating element 2 be a flat plate having a thickness of 1 to 50 μm and a width of 5 to 20 mm within the range of the aspect ratio. It is effective to increase the relative thickness of the heating element within the above range for the purpose of preventing disconnection and the like. The reason for limiting the thickness and width in this way is that this range is most practical for controlling the resistance value. The structure (thickness, width) of the heating element 2
The other reason for limiting as described above corresponds to the need to increase the width of the heating element itself. That is, the heating element 2
Embedded in the substrate 1, the heating surface 1a and the heating element 2
When the distance from the surface is short, the temperature uniformity of the surface is reduced, so that it is effective to increase the width.

When the heating element 2 is provided inside the substrate, it is not necessary to consider the adhesiveness with the nitride ceramic or the like. Therefore, a high melting point metal such as W or Mo, or a carbide such as W or Mo can be used. It is possible to increase the resistance value. The resistance value increases as the heating element 2 becomes thinner and thinner.

The heating element 2 may have a cross section of any one of a square, an ellipse, a spindle, and a semicylindrical shape as long as it is a flat plate. The reason why the flat plate-like body is adopted is that, when a heating element is provided inside, the flat shape is easier to dissipate heat toward the heating surface, so that a biased temperature distribution of the heating surface is not easily generated. In addition, even if the cross section of the heating element is flat, it is not included in the present invention if it is formed in a spiral shape. That is, this is because, when molded in this manner, the cross-section exhibits the same heat propagation action as a circular shape.

The heating element 2 may be arranged in a plurality of layers in the thickness direction of the substrate 1. In this case, the pattern of each layer is preferably buried in a position that complements each other when viewed from a plane, and somewhere on the heating surface is always covered by the pattern of any layer. Be buried. For example, the structures are arranged in a staggered pattern. The heating element 2 also includes a substrate 1
As long as it is embedded in the substrate, a part thereof may be exposed from the substrate surface.

In the present invention, the heating element is disposed at a predetermined position on the substrate 1 by applying or printing a conductive paste containing metal particles or the like at a predetermined position in the thickness direction of the substrate. Form. The conductive paste generally contains a resin, a solvent, a thickener, and the like, in addition to metal particles or conductive ceramic for securing conductivity. Noble metals (Au, Ag, Pt, Pd),
One or more selected from W and Mo are used. This is because these metals are relatively hard to oxidize and have a resistance value sufficient to generate heat. As the conductive ceramic, W
One or more selected from carbides of Mo and Mo can be used. It is desirable that the particle size of the metal particles or the conductive ceramic is 0.1 to 100 μm. If it is too fine, it is easily oxidized, and if it is too large, it becomes difficult to sinter,
This is because the resistance value increases.

As the resin used for the conductive paste,
Epoxy resin, phenol resin and the like are preferable. As the solvent, isopropyl alcohol or the like is used.
Examples of the thickener include cellulose and the like.

In the present invention, since the heating element is formed inside the ceramic substrate, the surface of the heating element is not oxidized. Therefore, it is not necessary to cover the surface of the heating element with an antioxidant or the like.

When the heating element 2 is formed inside the ceramic substrate 1, connection pads 4 for connecting to external terminals are required. This connection pad 4 can be formed by filling a through-hole (via hole) opened toward the heating element 2 from the surface of the substrate 1 opposite to the heating surface with a tungsten paste. It is preferable that the diameter of the connection pad 4 be 0.1 to 10 mm. That is, if the size of the connection pad 4 is about this size, it is effective in preventing cracks and distortion while preventing disconnection. This connection pad 4
It is connected to the external terminal pins 3 via the brazing material. This connection is performed by inserting and filling a brazing material together with the pins 3 into the openings 5 provided in the connection pads 4. As the brazing material, an Au-Ni alloy is desirable. This is because the Au-Ni alloy has excellent adhesion to tungsten. The ratio of this Au / Ni alloy is 80-90% Au / 10-20.
% Ni is desirable. The thickness of the Au-Ni alloy layer is desirably 0.1 to 50 µm in order to secure the connection.

In the present invention, the thermocouple 6 can be embedded in the ceramic substrate 1 as needed. This is because the temperature of the ceramic substrate 1 is measured by a thermocouple, and the voltage and current amount can be changed based on the data to control the temperature of the heater plate.

In a mode of use of the substrate according to the present invention as a ceramic heater, as shown in FIG. 2, a plurality of through holes 7 are provided in the ceramic substrate 1, and a support pin 8 is inserted through the through hole 7. The semiconductor wafer 9 is supported on the top of the substrate 8 so as to face the heating surface of the substrate 1, and is heated and dried. In this use mode, the semiconductor wafer 9 can be transferred to a carrier (not shown) by moving the support pins 8 up and down, or the semiconductor wafer 9 can be received from the carrier.

Next, a method of manufacturing the above ceramic heater will be described. (1) A step of mixing a ceramic powder such as a nitride ceramic and a carbide ceramic with a binder and a solvent to obtain a green sheet (form): In the process of this step, the ceramic powder may be aluminum nitride,
Silicon carbide or the like can be used, and a sintering aid such as yttria may be added as necessary. The binder is at least one selected from an acrylic binder, ethyl cellulose, butyl cellosolve, and polyvinylal.
More than species are desirable. Further, the solvent is desirably at least one selected from α-terpione and glycol.

The paste obtained by mixing them is formed into a sheet by a doctor blade method to produce a green sheet. A through hole 7 for inserting a support pin 8 for a silicon wafer into the green sheet if necessary.
Alternatively, a concave portion 11 into which a thermocouple is embedded can be provided. These through holes 7 and concave portions 11 can be formed by applying a punching method or the like. The thickness of the green sheet is preferably about 0.1 to 5 mm.

(2) Step of printing a conductive paste serving as a heating element on the green sheet: In the process of this step, a conductive paste made of a metal paste or conductive ceramic is applied to a heating element forming portion on the green sheet. Apply or print. These conductive pastes contain metal particles or conductive ceramic particles. As such metal particles, tungsten or molybdenum is optimal, and as the conductive ceramic particles, carbide of tungsten or molybdenum is optimal. This is because it is difficult to be oxidized and the thermal conductivity is not easily reduced. The average particle size of the tungsten particles or molybdenum particles is 0.1 to 5
μm is good. This is because it is difficult to print the paste if the paste is too large or too small. As such a 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 kind of binder selected from acrylic, ethyl cellulose, butyl cellosolve, and polyvinylal, and at least one kind of solvent selected from α-terpione and glycol are 1.5 to 1 part.
A tungsten paste or a molybdenum paste adjusted by mixing 0 parts by weight is optimal.

(3) At least each of the green sheet printed with the conductive paste for the heating element 2 obtained in the step (2) and the green sheet not printed with the paste obtained in the same step as the step (1) Step of laminating one or more sheets: In this step, when laminating one or more layers of two types of green sheets, the green sheet to be laminated on the upper side (meaning the heating surface side) of the green sheet with paste of (2) is used. It is important to make the number smaller than the number of the green sheets (1) laminated on the lower side so that the embedded position of the heating element 2 is eccentric in the thickness direction. Specifically, 20 to 50 sheets are stacked on the upper side, and 5 to 20 sheets are stacked on the lower side.

(4) Step of heating and pressing the green sheet laminate to sinter the green sheet and the conductive paste to obtain a ceramic substrate and a heating element: In this step, the heating temperature is 1000 to 2000 ° C. Pressurization is 1
It is carried out under an inert gas atmosphere at 00 to 200 kg / cm ² . As the inert gas, argon, nitrogen and the like can be used.

(5) Finally, after solder paste is printed as a brazing material in the openings 5 connected to the connection pads 4, the external terminal connection pins 3 are placed and heated to reflow. The heating temperature is preferably from 200 to 500C. Further, the thermocouple 6 can be embedded as needed. Incidentally, also in the exemplified ceramic heater, an electrostatic chuck electrode (not shown) may be embedded between the wafer heating surface and the heating element.

The hot plate (ceramic heater) has been described as an example of the ceramic substrate for a semiconductor manufacturing / inspection apparatus. Other embodiments of the present invention include, for example, an electrostatic chuck, a wafer prober, and a susceptor in addition to the ceramic heater. For example, when an electrostatic electrode is provided as the conductor embedded in a ceramic substrate constituting a semiconductor manufacturing / inspection apparatus, it functions as an electrostatic chuck 101. In order to form the conductor to be the electrostatic electrode, the same conductive paste as the above-described heater conductive paste can be applied, and the same substrate is used.

FIG. 5 is a longitudinal sectional view schematically showing a ceramic substrate used for an electrostatic chuck. In this ceramic substrate for an electrostatic chuck, chuck positive / negative electrode layers 52 and 53 are embedded in the ceramic substrate 1 and connected to through holes 56 and 57, respectively, and a ceramic dielectric film 54 is formed on the electrodes. I have.

On the other hand, a resistance heating element 55 and a through hole 58 are provided inside the ceramic substrate 1 so that a semiconductor product 9 to be heated such as a silicon wafer can be heated. Note that an RF electrode may be embedded in the ceramic substrate 1 as necessary. When the ceramic substrate according to the present invention is applied to the above-mentioned electrostatic chuck, the arrangement of the conductors, that is, the electrodes, is improved, so that a substrate having excellent adsorption characteristics such as a wafer can be obtained.

Next, as another embodiment of the ceramic substrate constituting the semiconductor manufacturing / inspection apparatus according to the present invention,
When a chuck top conductor layer is provided on the surface of the substrate and a guard electrode or a ground electrode is provided as an internal conductor, a material functioning as a wafer prober 102 is obtained.

FIG. 6 is a cross-sectional view schematically showing one embodiment of a ceramic substrate constituting a wafer prober.
In this wafer prober, a concentric groove 62 is formed on the surface of the ceramic substrate 1 having a circular shape in a plan view, and a plurality of suction holes 63 for sucking a silicon wafer are provided in a part of the groove 62. A chuck top conductor layer 64 for connecting to an electrode of a silicon wafer is formed in a circular shape on most of the ceramic substrate 1 including the groove 62.

On the other hand, at a position close to the surface opposite to the chuck top conductor layer 64 in the ceramic substrate 1, a resistance heating element arranged concentrically in a plan view to control the temperature of the silicon wafer is provided. Body 65 is embedded. Both ends of this resistance heating element 65 are provided with through holes 66.
The external terminal is connected and fixed via.

In this embodiment, a lattice-shaped guard electrode 67 and a ground electrode 68 are provided inside the ceramic substrate 1 in order to remove stray capacitors and noise. In such a wafer prober 102, after a silicon wafer on which an integrated circuit is formed is placed on the ceramic substrate 1, a probe card having tester pins is pressed against the silicon wafer.
A continuity test can be performed by applying a voltage while heating and cooling. However, because of its excellent adsorption characteristics, it is possible to obtain a product having excellent processing capability in the inspection process.

[0039]

EXAMPLES Example 1 (Ceramic heater) (1) Aluminum nitride powder (manufactured by Tokuyama, average particle size 1.1)
μm) 100 parts by weight, yttria (yttrium oxide, average particle size 0.4 μm) 4 parts by weight, acrylic binder
A composition obtained by mixing 11.5 parts by weight, 0.5 part by weight of a dispersant, and 53 parts by weight of alcohol composed of 1-butanol and ethanol was formed with a doctor blade to obtain a 0.47 mm thick green sheet. (2) After drying the green sheet at 80 ° C. for 5 hours,
A through hole 7 for inserting a semiconductor wafer support pin having a diameter of 1.8 mm, 3.0 mm, or 5.0 mm by punching, and a hole for forming a connection pad 4 for connecting the heating element 2 and the terminal pin 3 are provided. . (3) Tungsten carbide particles 10 having an average particle diameter of 1 μm
0 parts by weight, acrylic binder 3.0 parts by weight, 3. α-
A conductive paste A was prepared by mixing 3.5 parts by weight of a terpione solvent and 0.3 parts by weight of a dispersant. 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-terpione solvent, and 0.2 parts by weight of a dispersant. The conductive paste A was printed on a green sheet by drawing a pattern by screen printing. The printing pattern was a concentric circle as shown in FIG. The conductive paste B was filled in the holes for forming the connection pads 4 for connecting to the terminal pins (FIG. 2). Further, 37 green sheets on which no tungsten paste was printed were laminated on the upper side (heating surface) and 13 on the lower side at 130 ° C. under a pressure of 80 kg / cm ² . (4) The laminate was degreased in nitrogen gas at 600 ° C for 5 hours,
° C., 3 hours hot pressed at 150 kg / cm ^2, thickness 3
mm was obtained. This is 230 mm in diameter
Heating element with a thickness of 6μm and a width of 10mm inside
(Aspect ratio 1667) made of a ceramic plate (FIG. 3A). (5) The plate obtained in (4) was polished with a diamond grindstone, a mask was placed, and a recess 11 for the thermocouple 6 was provided by blasting with glass beads (FIG. 3 (b)). ). (6) Further, a part of the surface of the connection pad 4 is cut off, and FIG.
An opening 5 was formed as shown in FIG. 3, and a brazing material made of a Ni-Au alloy was used for the opening 5, and the terminal pin 3 made of Kovar was connected by heating and reflow at 700 ° C. (FIG. 3 (c)). The terminal pins 3 are connected to a tungsten support as shown in FIG.
It is desirable to have a structure in which 12 is supported at three points.
This is because connection reliability can be ensured. (7) A plurality of thermocouples 6 for temperature control were buried in the recess 11 to obtain a heater 100 (FIG. 3 (d)).

Example 2 (Silicon carbide ceramic plate heater) Basically the same as in Example 1, but 100 parts by weight of silicon carbide powder having an average particle diameter of 1.0 μm, 11.5 parts by weight of an acrylic binder, and 0.5 of a dispersant. A green sheet having a thickness of 0.50 mm was obtained by forming a composition in which a mixture of 1 part by weight and 53 parts by weight of alcohol composed of 1-butanol and ethanol was mixed with a doctor blade. The sintering temperature was 1900 ° C., and a ceramic heater was formed.

Comparative Example 1 Basically the same as in Example 1, except that the heating element was not a flat plate, but a square having a thickness of 20 μm × width of 20 μm (aspect ratio 1).

Comparative Example 2 Basically the same as Example 1, except that the heating element was not a flat plate but the cross-section was 5 μm × width 60
μm (aspect ratio 12000).

Example 3 Basically the same as Example 1, except that the heating element was not a flat plate, but had a cross section of 6 μm thick × 0.24 mm wide (aspect ratio 40).

Example 4 Basically the same as Example 1, except that the heating element was not a flat plate, but had a cross section of 6 μm thick × 33 mm wide (aspect ratio 5500).

The following table shows the response time when the temperature rises and falls, the temperature difference between the maximum temperature and the minimum temperature of the heating surface measured by a thermoviewer, and the thermal shock for each of the heater conforming to the present invention and the heater of the comparative example. Characteristic ΔT (The ceramic heater is heated to 100 to 400 ° C, dropped into water, cut out from the ceramic substrate, the bending strength is measured, and a graph of the temperature and bending strength is created. The temperature was lowered to ΔT.), And the superiority of the example of the present invention was confirmed.

[Table 1]

Example 5 (Electrostatic chuck) (1) Aluminum nitride powder (manufactured by Tokuyama Co., Ltd .;
1 μm) 100 parts by weight, yttria (average particle size: 0.4 μm)
m) 4 parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.
Using a paste obtained by mixing 5 parts by weight and 53 parts by weight of alcohol composed of 1-butanol and ethanol, molding was performed by a doctor blade method to obtain a green sheet having a thickness of 0.47 mm. (2) Next, after drying this green sheet at 80 ° C. for 5 hours, the diameter is 1.8 mm, 3.0 mm, 5.0 mm by punching.
A portion to be a through hole through which the semiconductor wafer support pins are inserted,
A portion serving as a through hole for connection to an external terminal was provided.

(3) 100 parts by weight of tungsten carbide particles having an average particle size of 1 μm, 3.0 parts by weight of an acrylic binder, 3.5 parts by weight of an α-terpineol solvent, and a dispersant of 0.1 part by weight.
3 parts by weight 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 conductor 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. 7 was formed on another green sheet.

Further, a conductive paste B was filled in a through hole for a through hole for connecting an external terminal. 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 130
The laminate was formed by pressing at 80 ° C. and a pressure of 80 kg / cm ² .

(4) Next, the obtained laminate is placed in nitrogen gas.
Degreasing at 600 ° C for 5 hours, 1890 ° C, pressure 0-150 kg / cm ²
(Details in Table 1) were hot pressed for 3 hours to obtain a 3 mm thick aluminum nitride plate. This was cut out into a 230 mm disk shape, and a 6 mm thick, 10 mm wide resistance heating element 5 was formed inside.
A plate made of aluminum nitride and having a 5 mm and a 10 μm thick chuck positive electrostatic layer 52 and a chuck negative electrostatic layer 53 was prepared.

(5) Next, the plate-like body obtained in (4) is polished with a diamond grindstone, a mask is placed thereon, and blasting treatment with SiC or the like is performed to form a bottomed hole for a thermocouple on the surface. (Diameter: 1.2 mm, depth: 2.0 mm). (6) Further, the portion where the through hole is formed is cut out to form a blind hole, and a gold solder made of Ni-Au is used in the blind hole, and heated and reflowed at 700 ° C. to connect an external terminal 59 made of Kovar. did. The connection of the external terminals 59 is preferably a structure in which a tungsten support is supported at three points as shown in FIG. This is because connection reliability can be ensured.

(7) Next, a plurality of thermocouples for temperature control are embedded in the bottomed holes, and the electrostatic chuck has a resistance heating element.
Production of 101 completed. With respect to such an electrostatic chuck, the temperature difference (the maximum temperature and the minimum temperature) of the heated surface due to the thermoviewer was 8 ° C. The response time was 0.8 sec. Further, the variation in the attraction force was within 5%.

Example 6 (Wafer prober) (1) Aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size: 1.)
1 μm) 100 parts by weight, yttria (average particle size 0.4 μm)
A mixed composition obtained by mixing 4 parts by weight, 0.9 part by weight of the amorphous carbon obtained in Example 1, and 53 parts by weight of an alcohol composed of 1-butanol and ethanol was molded by a doctor blade method. Then, a green sheet having a thickness of 0.47 mm was obtained. (2) Next, after drying the green sheet at 80 ° C. for 5 hours, a through-hole for a through-hole for connecting the heating element to an external terminal was provided by punching.

(3) 100 parts by weight of tungsten carbide particles having an average particle diameter of 1 μm, 3.0 parts by weight of an acrylic binder, 3.5 parts by weight of an α-terpineol solvent, and a dispersant of 0.1 part by weight.
The conductive paste A was prepared by mixing 3 parts by weight. In addition, 100 parts by weight of tungsten particles having an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, and α-terpineol solvent in 3.
A conductive paste B was prepared by mixing 7 parts by weight and 0.2 part by weight of a dispersant. Next, a grid-shaped printed body for a guard electrode and a printed body for a ground electrode were printed on the green sheet by screen printing using the conductive paste A. Further, a conductive paste B was filled in a through hole for a through hole for connecting to an external terminal. Further, 50 printed green sheets and unprinted green sheets were laminated and integrated at 130 ° C. under a pressure of 80 kg / cm ² to produce a laminate.

(4) Next, this laminate is placed in nitrogen gas for 600 minutes.
After degreasing at 5 ° C. for 5 hours, hot pressing was performed at 1890 ° C. under a pressure of 150 kg / cm ² for 3 hours to obtain a 3 mm-thick aluminum nitride plate. The obtained plate was cut into a circular shape having a diameter of 300 mm to obtain a ceramic plate. The size of the through hole 16 was 0.2 mm in diameter and 0.2 mm in depth. The thickness of the guard electrode 67 and the ground electrode 68 is 10 μm, the formation position of the guard electrode 67 is 1 mm from the wafer mounting surface, and the formation position of the ground electrode 68 is 1.2 mm from the wafer mounting surface.
Met. The guard electrode 67 and the ground electrode 6
The size of one side of the conductor-free region of No. 8 was 0.5 mm.

(5) The plate obtained in (4) is polished with a diamond grindstone, a mask is placed on the plate, and a blast process using SiC or the like is performed on the surface to form a concave portion for a thermocouple and a wafer suction device. A groove 62 (width 0.5 mm, depth 0.5 mm) was provided.

(6) Further, a layer for forming the heating element 65 was printed on the surface facing the wafer mounting surface. For printing, a conductive paste was used. As the conductive paste, Solvest PS603D manufactured by Tokuri Chemical Laboratory, which is used for forming through holes in a printed wiring board, was used. The conductive paste is a silver / lead paste, and a metal oxide composed of lead oxide, zinc oxide, silica, boron oxide, and alumina (the weight ratio of each is 5/55/10/25/5) is 100 weight of silver. 7.5 parts by weight per part by weight. The silver had a scaly shape with an average particle size of 4.5 μm.

(7) After printing the conductive paste, it was heated and fired at 780 ° C. to sinter silver and lead in the conductive paste and to bake it on the ceramic substrate 1. In addition, nickel sulfate 30g / l, boric acid 30g / l, ammonium chloride 30g
The substrate is immersed in an electroless nickel plating bath composed of an aqueous solution containing 1 g / l and Rochelle salt 60 g / l, and a nickel layer having a thickness of 1 μm and a boron content of 1% by weight or less is formed on the surface of the silver sintered body. (Not shown) was deposited. Thereafter, the substrate was annealed at 120 ° C. for 3 hours. The heating element made of a silver sintered body had a thickness of 5 μm, a width of 2.4 mm, and a sheet resistivity of 7.7 mΩ / □.

(8) A titanium layer, a molybdenum layer, and a nickel layer were sequentially formed on the surface where the grooves 62 were formed by a sputtering method. As a device for sputtering, SV-4540 manufactured by Japan Vacuum Engineering Co., Ltd. was used. The sputtering conditions were as follows: atmospheric pressure 0.6 Pa, temperature 100 ° C, power 20
0 W, and the sputtering time was adjusted for each metal within the range of 30 seconds to 1 minute. The thickness of the obtained film was 0.3 μm for the titanium layer from the image of the fluorescent X-ray analyzer.
The molybdenum layer was 2 μm and the nickel layer was 1 μm.

(9) Nickel sulfate 30 g / l, boric acid 30 g /
l, ammonium chloride 30 g / l and Rochelle salt 60 g
/ L in an electroless nickel plating bath consisting of an aqueous solution containing
The ceramic substrate obtained in the above (8) is immersed, and a nickel layer having a thickness of 7 μm and a boron content of 1% by weight or less is deposited on the surface of the metal layer formed by sputtering,
Annealed at 120 ° C. for 3 hours. The surface of the heating element does not pass current and is not covered with electrolytic nickel plating.

Further, 2 g of potassium potassium cyanide /
l, ammonium chloride 75 g / l, sodium citrate 50
g / l and 10 g / l of sodium hypophosphite in an electroless gold plating solution at 93 ° C. for 1 minute to form a 1 μm thick gold plating layer on the nickel plating layer.

(10) An air suction hole 63 extending from the groove 62 to the back surface is formed by drilling.
A blind hole (not shown) for exposing 6 was provided. Ni-Au alloy (Au: 81.5% by weight, Ni: 18.4% by weight,
Using a gold solder made of impurities (0.1% by weight), heating and reflow were performed at 970 ° C. to connect external terminals made of Kovar.
External terminals made of Kovar were formed on the heating element via solder (90% by weight of tin / 10% by weight of lead).

(11) Next, a plurality of thermocouples for temperature control were buried in the recesses to obtain a wafer prober 102. Such a wafer prober has a difference in temperature when heated to 200 ° C.
The temperature was 0.5 ° C and the response time was 0.8 sec. In addition, there was no erroneous determination.

[0063]

As described above, the ceramic substrate according to the present invention is practical because it is thin and light. In addition, by using a thin plate of nitride ceramic or carbide ceramic with good thermal conductivity, the substrate has excellent responsiveness (temperature follow-up) to changes in voltage and current, making temperature control easy. In addition, there is an effect that the temperature rise and fall characteristics are excellent. Furthermore, when this substrate is used as a heater,
The uniformity of the temperature distribution on the heating surface is excellent due to the eccentricity of the heating element. On the other hand, in the case of using an electrostatic chuck or a wafer prober, one having excellent suction characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a pattern of a heating element.

FIG. 2 is a partial longitudinal sectional view showing a use state of a ceramic heater.

FIG. 3 is a schematic view illustrating a manufacturing process of the ceramic heater.

FIG. 4 is a perspective view showing a structure of a terminal connecting portion.

FIG. 5 is a vertical sectional view of the electrostatic chuck.

FIG. 6 is a vertical sectional view of a wafer prober.

FIG. 7 is a schematic view of an internal electrode pattern of the electrostatic chuck.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic substrate 2 Heating element 3 Terminal pin 4 Connection pad 5 Opening 6 Thermocouple 7 Through hole 8 Semiconductor wafer support pin 9 Semiconductor product 11 Depression 12 Support 100 Ceramic heater 101 Electrostatic chuck 102 Wafer prober

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H05B 3/20 393 C04B 35/58 104Y H01L 21/302 B

Claims (4)

[Claims] 1. An insulating ceramic substrate having a cross-sectional aspect ratio (conductor width / conductor thickness) of 10 to 10
A ceramic substrate for a semiconductor manufacturing / inspection apparatus, in which 000 flat conductors having a flat shape are embedded. 2. The conductor has a cross-sectional aspect ratio of 50.
The ceramic substrate according to claim 1, wherein the number is from 5,000 to 5,000. 3. The method according to claim 1, wherein the conductor is formed at a position deviated in the thickness direction from the center of the thickness of the ceramic substrate, and a surface far from the embedded heat generating element is used as a work surface. The ceramic substrate according to claim 1. 4. The ceramic according to claim 1, wherein the conductor is a heating element for a heater and a susceptor, an electrode for an electrostatic chuck, and an electrode for a wafer prober. substrate.