JP2003203955A - Wafer prober and ceramic substrate therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic substrate which is fully blackened, capable of concealing a guard electrode and a gland electrode, as well as ensuring thermal conductivity and volume resistivity sufficient to function as a wafer prober. <P>SOLUTION: The ceramic substrate for the wafer prober with a chuck top conductor layer formed on the surface thereof is provided, wherein an X-ray diffraction chart of the ceramic substrate, in addition to a peak of the ceramic constituting a main crystal phase thereof, a peak of carbon is detected to an angle of X-ray diffraction of 2θ=44 to 45°. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer prober mainly used in the semiconductor industry and a ceramic substrate used for the wafer prober, and more particularly, to a thin and light wafer prober and a wafer prober excellent in temperature raising and lowering characteristics. The present invention relates to a ceramic substrate used for.

[0002]

2. Description of the Related Art Semiconductors are extremely important products required in various industries.
It is manufactured by slicing a silicon single crystal into a predetermined thickness to manufacture a silicon wafer, and then forming various circuits and the like on the silicon wafer. In the manufacturing process of this semiconductor chip, a probing process for measuring and checking whether or not the electrical characteristics of the silicon wafer operate as designed is necessary at the stage of the silicon wafer, and a so-called prober is used for that purpose.

An example of such a prober is a patent.
No. 2587289, Japanese Patent Publication No. 3-4047
In Japanese Patent Laid-Open No. 11-31724, there is
Has a chuck top made of metal such as aluminum alloy or stainless steel
A wafer prober is disclosed. Such a
In the haplober, for example, as shown in FIG.
Place the silicon wafer W on the prober 501 and
Probe card 60 with tester pins on recon wafer W
Press 1 and apply voltage while heating and cooling to conduct electricity.
Do the test. In FIG. 12, V₃ Is a plow
Power supply 33, V applied to the bucard 601 ₂ Resistance heating
Power supply 32, V applied to body 41₁ Led chuck top
A power source 31 applied to the body layer 2 and the guard electrode 5,
The power supply 31 is also connected to the ground electrode 6 and is grounded.
There is.

[0004]

However, a wafer prober having such a metal chuck top has the following problems.
There were the following problems. First, since it is made of metal, the thickness of the chuck top must be large, about 15 mm. In order to make the chuck top thicker, a thin metal plate is pressed on the chuck top by the tester pins of the probe card, warping or distorting the metal plate of the chuck top, and placing it on the metal plate. This is because the silicon wafer may be damaged or tilted. Therefore, it is necessary to make the chuck top thick, but as a result, the weight of the chuck top becomes large and bulky.

In addition, even though a metal having a high thermal conductivity is used, the temperature rising and cooling characteristics are poor, and the temperature of the chuck top plate does not quickly follow changes in voltage or current amount. It is difficult to control, and if the silicon wafer is placed at a high temperature, the temperature cannot be controlled.

[0006]

Therefore, the present inventors have
It was recalled that instead of a metal chuck top, a conductor layer was provided on the surface of a ceramic substrate having high rigidity and this was used as the chuck top conductor layer.
When transparent, the shapes of the guard electrode and the ground electrode can be observed through the ceramic layer, and color unevenness is likely to occur, which is unfavorable in appearance and reduces the commercial value. Therefore, a method of adding a metal or the like to blacken the color has been proposed, but there has been a problem that the volume resistivity at high temperature is lowered. With a wafer prober,
When the volume resistivity at high temperature decreases, a voltage is applied between the chuck top conductor layer and the ground electrode, which causes dielectric breakdown. Further, ceramic has a problem that its thermal conductivity decreases at high temperature, and it is necessary to secure the thermal conductivity at high temperature.

Therefore, the present inventors have made further studies,
By using a specific carbon, it has been found that the ceramic substrate can be blackened while the volume resistivity at high temperature is not lowered and the thermal conductivity is secured, and the present invention has been completed.

That is, the wafer prober of the present invention is a wafer prober in which a chuck top conductor layer is formed on the surface of a ceramic substrate, and in the X-ray diffraction chart of the ceramic substrate, the ceramic constituting the main crystal phase is formed. In addition to the peak, a carbon peak is detected at an X-ray diffraction angle 2θ = 44 to 45 °. Also,
The ceramic substrate of the present invention is a ceramic substrate having a chuck top conductor layer formed on the surface thereof, and in the X-ray diffraction chart of the ceramic substrate, in addition to the peak of the ceramic constituting the main crystal phase, the X-ray Diffraction angle 2
A feature is that a carbon peak is detected at θ = 44 to 45 °. In the wafer prober and the ceramic substrate used for the wafer prober, it is desirable that the main component of the ceramic substrate is aluminum nitride.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The wafer prober of the present invention (hereinafter,
(Including ceramic substrates used in wafer probers)
Is a wafer prober in which a chuck top conductor layer is formed on the surface of a ceramic substrate, and in the X-ray diffraction chart of the above-mentioned ceramic substrate, in addition to the peak of the ceramic constituting the main crystal phase, the X-ray diffraction angle 2θ = 44 ~
It is characterized in that a carbon peak is detected at 45 °. The ceramic substrate of the present invention is used in a wafer prober, and specifically functions as a probing stage (so-called chuck top) for a semiconductor wafer.

In the present invention, since the above-mentioned ceramic substrate contains carbon and the peak of carbon is detected at the X-ray diffraction angle 2θ = 44 to 45 °, it is sufficiently blackened and the guard electrode, The ground electrode can be hidden. Further, since the carbon to be added is carbon having crystallinity that can be detected by X-ray diffraction, it has excellent thermal conductivity at high temperatures and suppresses a decrease in the thermal conductivity of the ceramic in the high temperature region. It is possible to secure a volume resistivity of about 10 ¹¹ to 10 ¹² Ω · cm at 200 ° C. When a metal or the like is added, the volume resistivity of the ceramic substrate decreases to about 1 × 10 ⁷ Ω · cm at 200 ° C. However, in the present invention, since the above carbon is used, it is necessary for the wafer prober. Insulation resistance can be secured.

In the present invention, since the substrate made of high-rigidity ceramic is used, even if the chuck top is pushed by the tester pin of the probe card, the chuck top does not warp, and the thickness of the chuck top is made metal. It can be made thinner than in comparison.

Furthermore, since the thickness of the chuck top can be made thinner than that of metal, even if the ceramic has a thermal conductivity lower than that of metal, the heat capacity is reduced as a result.
The temperature rising / falling characteristics can be improved.

FIG. 1 is a sectional view schematically showing an embodiment of a wafer prober of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a bottom view thereof, and FIG. 2 is a cross-sectional view taken along the line AA of the wafer prober shown in FIG.

In this wafer prober 101, concentric circular grooves 7 are formed on the surface of a ceramic substrate 3 which is circular in plan view, and a plurality of suction holes 8 for sucking a silicon wafer are formed in a part of the grooves 7. The chuck top conductor layer 2 for connecting to the electrodes of the silicon wafer is formed in a circular shape on most of the ceramic substrate 3 including the groove 7.

On the other hand, the bottom surface of the ceramic substrate 3 is provided with a concentric heating element 41 in plan view as shown in FIG. 3 for controlling the temperature of the silicon wafer. Has an external terminal pin 191 connected and fixed thereto. In addition, a guard electrode 5 and a ground electrode 6 are provided inside the ceramic substrate 3 for removing stray capacitors and noise. In this ceramic substrate 3, carbon peaks can be observed by X-ray diffraction. It contains crystalline carbon that is present at the grain boundaries to some extent, and as a result, it becomes black and the guard electrode 5 and the ground electrode 6 are completely hidden.

The wafer prober of the present invention is shown in FIG.
~ 4 has a configuration as shown. In the following, each member constituting the wafer prober, and
Other embodiments of the wafer prober of the present invention will be sequentially described in detail.

In the present invention, the ceramic substrate contains carbon, and the carbon peak is detected at the X-ray diffraction angle 2θ = 44 to 45 °, so that it is blackened. However, if the carbon peak is not detected at the X-ray diffraction angle 2θ = 44 to 45 °, the amount of carbon is small, so that the degree of blackening is small and it is difficult to use the blackbody radiant heat. Become.

The carbon content is 100 to 5,000.
ppm is preferred. If the carbon content is less than 100 ppm, the carbon peak is not detected at the X-ray diffraction angle 2θ = 44 to 45 °, the ceramic substrate becomes white and transparent, and color unevenness easily occurs, while the carbon content is 500.
If it exceeds 0 ppm, the volume resistivity at high temperature may decrease and dielectric breakdown may occur. The amount of carbon is, in particular, 500 to 2
000 ppm is desirable. This is because it is possible to prevent a decrease in thermal conductivity at high temperature without impairing sinterability.

FIG. 13 is an X-ray diffraction chart of a ceramic substrate made of aluminum nitride containing carbon, and FIG. 14 is an X-ray diffraction chart of a ceramic substrate made of aluminum nitride containing no carbon. .

As is clear from the comparison between FIG. 13 and FIG. 14, there is a carbon peak at the X-ray diffraction angle 2θ = 44 to 45 ° in addition to the aluminum nitride peak constituting the main crystalline phase.

Thus, the presence of carbon peaks in X-ray diffraction means that the added carbon does not form a solid solution in the aluminum nitride particles but segregates at the grain boundaries. However, it is considered that the ceramic substrate made of aluminum nitride becomes black due to the carbon (graphite), and thus the volume resistivity decreases.

FIG. 15 is a graph schematically showing the relationship between the temperature and the volume resistivity of a ceramic substrate made of aluminum nitride containing 800 ppm of carbon. The volume resistivity decreases as the temperature rises. But 2
The volume resistivity near 00 ° C. is sufficiently large, and dielectric breakdown of the ceramic substrate can be prevented.

FIG. 16 shows that carbon is 800 ppm.
3 is a graph schematically showing the relationship between the temperature and the thermal conductivity of the contained aluminum nitride ceramic substrate.
As shown in FIG. 16, when crystalline carbon is used, the decrease in high temperature thermal conductivity is small, and high thermal conductivity at high temperature can be secured.

JIS Z 872 of the above ceramic substrate
The lightness based on 1 is preferably N4 or less. The brightness is a scale indicating a visual attribute for determining whether the reflectance of the object surface is high or low. JIS Z 872
The lightness based on 1 is based on an achromatic color, and the ideal lightness of black is 0 and the ideal lightness of white is 10. Between ideal black and ideal white, each color is divided into 10 so that the perception of the brightness of the color becomes equal, and N0 to N10 are divided.
Display with the symbol. When measuring the brightness of an actual aluminum nitride sintered body, the standard color charts corresponding to N0 to N10 are compared with the surface color of the aluminum nitride sintered body to determine the brightness of the aluminum nitride sintered body. To do. At this time, in principle, the lightness is determined up to the first decimal place, and the value at the first decimal place is 0 or 5.

By setting the amount of carbon contained in the ceramic substrate to 100 to 5000 ppm, the brightness of the above-mentioned ceramic substrate according to JIS Z 8721 is N.
It can be 4 or less, and when the lightness is in the above range, the degree of blackening is large, so that black body radiant heat can be fully utilized during heating, and the internal guard electrode, ground electrode, etc. Can be hidden.

As the carbon, use is made of pyrolyzed powder of an organic resin such as phenol resin, carbon powder such as carbon black or graphite, and an intermediate product of aluminum nitride having a high carbon concentration produced in the process of reduction nitriding. can do.

As a method of incorporating carbon, a green sheet is prepared by mixing these resins and carbon powder with ceramic powder, or a green sheet is prepared by using an intermediate product of aluminum nitride having a high carbon concentration. Can be taken.

The ceramic substrate used in the wafer prober of the present invention is preferably at least one selected from the group consisting of nitride ceramics, carbide ceramics and oxide ceramics.

Examples of the nitride ceramics include metal nitride ceramics such as aluminum nitride, silicon nitride, boron nitride and titanium nitride. Further, as the above-mentioned carbide ceramics, metal carbide ceramics,
For example, silicon carbide, zirconium carbide, titanium carbide,
Examples thereof include tantalum carbide and tantalum carbide.

Examples of the oxide ceramics 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. Aluminum nitride is most preferable among the nitride ceramics. This is because the highest thermal conductivity is 180 W / m · K.

The thickness of the ceramic substrate of the chuck top in the present invention needs to be thicker than that of the chuck top conductor layer, and specifically 1 to 10 mm is desirable. Further, in the present invention, since the back surface of the silicon wafer is used as an electrode, the chuck top conductor layer is formed on the front surface of the ceramic substrate.

The thickness of the chuck top conductor layer is from 1 to
20 μm is desirable. This is because if it is less than 1 μm, the resistance value becomes too high to function as an electrode, and if it exceeds 20 μm, peeling easily occurs due to the stress of the conductor.

As the chuck top conductor layer, for example,
At least one metal selected from refractory metals such as copper, titanium, chromium, nickel, noble metals (gold, silver, platinum, etc.), tungsten, molybdenum, etc. can be used.

The chap conductor layer may be a porous body made of metal or conductive ceramic. In the case of a porous body, it is not necessary to form a groove for suction and adsorption as described later, it is possible to prevent the damage of the wafer due to the existence of the groove and also to uniformly suck and adsorb the entire surface. This is because As such a porous body,
A metal sintered body can be used. Moreover, when a porous body is used, the thickness thereof can be 1 to 200 μm. A solder or a brazing material is used for joining the porous body and the ceramic substrate.

The chuck top conductor layer preferably contains nickel. This is because the hardness is high and it is difficult to deform even when the tester pin is pressed. As a concrete configuration of the chuck top conductor layer, for example, a nickel sputtering layer is first formed, and an electroless nickel plating layer is provided thereon, or titanium, molybdenum and nickel are sputtered in this order, and The thing etc. which made nickel deposit on it by electroless plating or electrolytic plating etc. are mentioned.

Alternatively, titanium, molybdenum, and nickel may be sputtered in this order, and copper and nickel may be deposited thereon by electroless plating. This is because the resistance value of the chuck top electrode can be reduced by forming the copper layer.

Further, titanium and copper may be sputtered in this order, and nickel may be deposited thereon by electroless plating or electroless plating. Alternatively, chromium and copper may be sputtered in this order, and nickel may be deposited thereon by electroless plating or electroless plating.

Titanium and chromium can improve the adhesion to ceramics, and molybdenum can improve the adhesion to nickel. The thickness of titanium and chromium is 0.1 to 0.5 μm, the thickness of molybdenum is 0.5 to 7.0 μm, and the thickness of nickel is 0.4 to 2.5.
μm is desirable.

It is desirable that a precious metal layer (gold, silver, platinum, palladium) be formed on the surface of the chuck top conductor layer. This is because the noble metal layer can prevent contamination due to migration of the base metal. The thickness of the noble metal layer is preferably 0.01 to 15 μm.

In the present invention, it is desirable to provide the ceramic substrate with temperature control means. This is because the continuity test of the silicon wafer can be performed while heating or cooling.

As the temperature control means, a Peltier element may be used in addition to the heating element 41 shown in FIG. When the heating element is provided, a blowing port for a cooling medium such as air may be provided as a cooling means. The 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 the pattern is formed in any of the layers as viewed from the heating surface. For example, a structure in which staggered arrangement is provided.

Examples of the heating element include a sintered body of metal or conductive ceramic, a metal foil, a metal wire and the like. The metal sintered body is preferably at least one selected from tungsten and molybdenum. This is because these metals are relatively difficult to oxidize and have a resistance value sufficient to generate heat.

As the conductive ceramic, at least one selected from carbides of tungsten and molybdenum is used.
Seeds can be used. Further, when the heating element is formed on the outside of the ceramic substrate, it is desirable to use a noble metal (gold, silver, palladium, platinum) or nickel as the metal sintered body. Specifically, silver, silver-palladium, or the like can be used. The metal particles used in the metal sintered body may be spherical, flaky, or a mixture of spherical and flaky.

A metal oxide may be added to the metal sintered body. The reason why the above metal oxide is used is to bring the nitride ceramic or the carbide ceramic into close contact with the metal particles. It is not clear why the metal oxide improves the adhesion between the nitride ceramic or the carbide ceramic and the metal particle, but a slight oxide film is formed on the surface of the metal particle and the surface of the nitride ceramic or the carbide ceramic. Therefore, it is considered that the oxide films are sintered and integrated with each other through the metal oxide, and the metal particles and the nitride ceramic or the carbide ceramic adhere to each other.

Examples of the above metal oxide include, for example, oxidation.
Lead, zinc oxide, silica, boron oxide (B ₂ O₃ ), Al
At least one selected from Mina, Yttria, and Titania
Seeds are preferred. These oxides increase the resistance value of the heating element.
Metal particles and nitride ceramic or
This is because the adhesion with the carbide ceramic can be improved.

The above-mentioned metal oxide has a metal content of 0.
It is desirable to be 1% by weight or more and less than 10% by weight. This is because the resistance value does not become too large and the adhesion between the metal particles and the nitride ceramic or the carbide ceramic can be improved.

The proportions 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, lead oxide is 1 to 1. 10 parts by weight, 1 to 30 parts by weight of silica, 5 to 50 parts by weight of boron oxide, 20 to 7 of zinc oxide.
0 parts by weight, alumina 1 to 10 parts by weight, yttria 1
.About.50 parts by weight, and titania is preferably 1 to 50 parts by weight. However, it is desirable that the total amount of these components be adjusted within a range not exceeding 100 parts by weight. This is because these ranges are ranges in which the adhesion with the nitride ceramic can be improved.

When the heating element is provided on the surface of the ceramic substrate, it is desirable that the surface of the heating element is covered with the metal layer 410 (see FIG. 11 (e)). The heating element is a sintered body of metal particles, and if it is exposed, it is easily oxidized, and this oxidation changes the resistance value. Therefore, by coating the surface with a metal layer, oxidation can be prevented.

The thickness of the metal layer is preferably 0.1 to 10 μm. This is because the range can prevent oxidation of the heating element without changing the resistance value of the heating element. The metal used for coating may be a non-oxidizing metal. Specifically, at least one selected from gold, silver, palladium, platinum and nickel is preferable. Of these, nickel is more preferable. This is because the heating element needs a terminal for connecting to a power source, and this terminal is attached to the heating element via solder, but nickel prevents heat diffusion of the solder. A terminal pin made by Kovar can be used as the connection terminal. In addition, when the heating element is formed inside the heater plate, the surface of the heating element is not oxidized, and thus coating is unnecessary. When the heating element is formed inside the heater plate, a part of the surface of the heating element may be exposed.

As the metal foil used as the heating element, it is desirable to use a nickel foil or a stainless foil as a heating element by patterning by etching or the like. The patterned metal foil may be laminated with a resin film or the like. Examples of the metal wire include a tungsten wire and a molybdenum wire.

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. As shown in FIG. 7, the Peltier element is a p-type or n-type thermoelectric element 440.
Are connected in series and are joined to a ceramic plate 441 or the like. As a Peltier element,
For example, a silicon / germanium-based material, a bismuth / antimony-based material, a lead / tellurium-based material, or the like can be used.

In the present invention, it is desirable that at least one conductive layer is formed between the temperature control means and the chuck top conductive layer. The guard electrode 5 and the ground electrode 6 in FIG. 1 correspond to the conductor layer. Guard electrode 5
Is an electrode for canceling the stray capacitor interposed in the measurement circuit, and is supplied with the ground potential of the measurement circuit (that is, the chuck top conductor layer 2 in FIG. 1).
The ground electrode 6 is provided to cancel noise from the temperature control means. The thickness of these electrodes is preferably 1 to 20 μm. If it is too thin, the resistance value will be high, and if it is too thick, the ceramic substrate will warp and the thermal shock resistance will decrease.

These guard electrode 5 and ground electrode 6
Are preferably provided in a grid pattern as shown in FIG. That is, a large number of rectangular conductor layer non-forming portions 52 are arranged inside the circular conductor layer 51. This shape is used to improve the adhesion between the ceramics above and below the conductor layer. It is desirable that the surface of the wafer prober of the present invention on which the chuck top conductor layer is formed is provided with the groove 7 and the air suction hole 8 as shown in FIG. A plurality of suction holes 8 are provided to achieve uniform suction. This is because the silicon wafer W can be placed and the air can be sucked from the suction holes 8 to suck the silicon wafer W.

As the wafer prober in the present invention,
For example, as shown in FIG. 1, a heating element 41 is provided on the bottom surface of the ceramic substrate 3, and a layer of the guard electrode 5 and a layer of the ground electrode 6 are provided between the heating element 41 and the chuck top conductor layer 2, respectively. The wafer prober 101 having the above structure is provided with the flat heating element 42 inside the ceramic substrate 3 as shown in FIG. 5, and the guard electrode 5 and the ground electrode 6 are provided between the heating element 42 and the chuck top conductor layer 2. A wafer prober 201 having a structure in which a metal wire 43 as a heating element is embedded inside the ceramic substrate 3 as shown in FIG. 6, and a guard electrode 5 is formed between the metal wire 43 and the chuck top conductor layer 2. A wafer prober 301 having a structure provided with a ground electrode 6, and a Peltier device 44 as shown in FIG.
The Peltier element 44 (consisting of the thermoelectric element 440 and the ceramic substrate 441) is formed on the outside of the ceramic substrate 3.
Wafer prober 401 having a structure in which the guard electrode 5 and the ground electrode 6 are provided between the chuck top conductor layer 2 and the chuck top conductor layer 2.
Etc. Each wafer prober always has a groove 7 and a suction hole 8.

In the present invention, heating elements 42 and 43 are formed inside the ceramic substrate 3 as shown in FIGS. 1 to 7 (FIGS. 5 to 6), and the guard electrode 5 and the ground electrode 6 are formed inside the ceramic substrate 3. (FIGS. 1 to 7) are formed, and therefore a connecting portion (through hole) for connecting these to external terminals 1
6, 17, 18 are required. Through holes 16, 1
7, 18 are formed by filling a refractory metal such as tungsten paste or molybdenum paste, or a conductive ceramic such as tungsten carbide or molybdenum carbide.

Further, the connecting portions (through holes) 16, 1
The diameter of 7, 18 is preferably 0.1 to 10 mm. This is because it is possible to prevent cracks and distortions while preventing disconnection. External terminal pins are connected using the through holes as connection pads (see FIG. 11 (g)).

Connection is made with solder or brazing material. As a brazing material, silver brazing, palladium brazing, aluminum brazing,
Use gold wax. Au-Ni alloy is preferable for gold brazing. This is because the Au-Ni alloy has excellent adhesion to tungsten.

The Au / Ni ratio is [81.5 to 82.
5 (wt%)] / [18.5 to 17.5 (wt%)] is desirable. The thickness of the Au—Ni layer is preferably 0.1 to 50 μm. This is because the range is sufficient to secure the connection.
Moreover, at a high vacuum of 10 ⁻⁶ to 10 ⁻⁵ Pa, 500 ° C. to 100 ° C.
When used at a high temperature of 0 ° C., the Au—Cu alloy deteriorates, but the Au—Ni alloy is advantageous because it does not deteriorate. The total amount of impurity elements in the Au-Ni alloy is 1
When the amount is 00 parts by weight, it is preferably less than 1 part by weight.

In the present invention, a thermocouple can be embedded in the ceramic substrate if necessary. This is because the temperature of the heating element can be measured with a thermocouple and the temperature can be controlled by changing the voltage and current amount based on the data.
The size of the joining portion of the metal wires of the thermocouple is equal to or larger than the wire diameter of each metal wire, and 0.
5 mm or less is preferable. With such a configuration, the heat capacity of the joint portion is reduced, and the temperature is converted into a current value accurately and quickly. Therefore, the temperature controllability is improved and the temperature distribution on the heating surface of the wafer is reduced. As the thermocouple, for example, JIS-C-160
2 (1980), K type, R type, B type
Type, S type, E type, J type, and T type thermocouples.

FIG. 8 is a cross-sectional view schematically showing the support container 11 for installing the wafer prober of the present invention having the above structure. A coolant outlet 12 is formed in the support container 11, and the coolant is blown from the coolant inlet 14. Further, air is sucked from the suction port 13 and the silicon wafer (not shown) placed on the wafer prober is sucked into the groove 7 through the suction hole 8.

FIG. 9 (a) is a horizontal sectional view schematically showing another example of the supporting container, and FIG. 9 (b) is a sectional view taken along line BB in FIG. 9 (a). As shown in FIG. 9, the support container 21 is provided with a large number of support columns 15 so that the wafer prober does not warp due to the pressing of the tester pins of the probe card. An aluminum alloy, stainless steel, etc. can be used for a support container.

Next, an example of the method for manufacturing the wafer prober of the present invention will be described with reference to the sectional views shown in FIGS. (1) First, a green sheet 30 is obtained by mixing ceramic powder such as oxide ceramics, nitride ceramics, and carbide ceramics with carbon, a binder, and a solvent.

As the above-mentioned ceramic powder, for example, aluminum nitride, silicon carbide or the like can be used, and if necessary, a sintering aid such as yttria may be added. The carbon may be carbonized from a resin such as phenol resin, or may be carbon powder such as carbon black. Further, the carbon is preferably crystalline.

The binder is preferably at least one selected from acrylic binders, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol.
Further, the solvent is preferably at least one selected from α-terpineol and glycol. The paste obtained by mixing these is formed into a sheet by a doctor blade method to produce a green sheet 30.

If necessary, the green sheet 30 may be provided with through holes for inserting the support pins of the silicon wafer and recesses for embedding the thermocouple. Through holes and recesses
It can be formed by punching or the like. The thickness of the green sheet 30 is preferably about 0.1 to 5 mm.

Next, the green sheet 30 is provided with a guard electrode,
Print the ground electrode. Printed on the green sheet 30
Is performed so as to obtain a desired aspect ratio in consideration of the contraction rate of the guard electrode printed matter 50 and the ground electrode printed matter 60. The printed body is formed by printing a conductive paste containing conductive ceramics, metal particles and the like.

Carbide of tungsten or molybdenum is most suitable as the conductive ceramic particles contained in these conductive pastes. This is because it is difficult to oxidize and the thermal conductivity does not easily decrease. Further, as the metal particles, for example, tungsten, molybdenum, platinum, nickel or the like can be used.

The average particle diameter of the conductive ceramic particles and the metal particles is preferably 0.1 to 5 μm. This is because it is difficult to print the paste when these particles are too large or too small. As such a paste, 85 to 97 parts by weight of metal particles or conductive ceramic particles, at least one binder selected from acrylic, ethyl cellulose, butyl cellosolve and polyvinyl alcohol 1.5
The paste prepared by mixing 10 to 10 parts by weight, 1.5 to 10 parts by weight of at least one solvent selected from α-terpineol, glycol, ethyl alcohol and butanol is most suitable. Further, the holes formed by punching or the like are filled with a conductive paste, and the through-hole printed body 16 is formed.
You get 0,170.

Next, as shown in FIG. 10A, the green sheet 3 having the printed bodies 50, 60, 160 and 170.
0 and the green sheet 30 having no printed body are laminated. Green sheet 3 that does not have a printed body on the heating element formation side
The reason why 0 is stacked is to prevent the end face of the through hole from being exposed and being oxidized during firing for forming the heating element. If the firing for forming the heating element is performed with the end face of the through hole exposed, it is necessary to sputter a metal that is difficult to oxidize such as nickel, and more preferably, even if it is covered with Au—Ni gold brazing. Good.

(2) Next, as shown in FIG.
The laminated body is heated and pressed to sinter the green sheet and the conductive paste. The heating temperature is 1000-2
The pressure and pressure are preferably 100 to 200 kg / cm ² , and the heating and pressurization are performed in an inert gas atmosphere. As the inert gas, argon, nitrogen or the like can be used. Through holes 16 and 1 in this process
7, the guard electrode 5, and the ground electrode 6 are formed. Further, since the ceramic substrate contains carbon, it is blackened.

(3) Next, as shown in FIG.
Grooves 7 are provided on the surface of the sintered body by sandblasting or the like through a mask. (4) Next, as shown in FIG. 10 (d), a conductive paste is printed on the bottom surface of the sintered body and fired to produce the heating element 41. The formed heating element 41 firmly adheres to the surface of the ceramic substrate.

(5) Next, as shown in FIG.
After sputtering titanium, molybdenum, nickel or the like on the wafer mounting surface (groove forming surface), electroless nickel plating or the like is performed to provide the chuck top conductor layer 2. At the same time, a protective layer 410 is formed on the surface of the heating element 41 by electroless nickel plating or the like.

(6) Next, as shown in FIG.
A suction hole 8 penetrating from the groove 7 to the back surface and a blind hole 180 for connecting an external terminal are provided. It is preferable that at least a part of the inner wall of the blind hole 180 is made conductive, and the made conductive inner wall is connected to the guard electrode 5, the ground electrode 6, and the like.

(7) Finally, as shown in FIG. 11 (g), after the solder paste is printed on the mounting portion on the surface of the heating element 41, the external terminal pins 191 are mounted and heated for reflow. The heating temperature is preferably 200 to 500 ° C.

External terminals 19 and 190 are also provided in the bag hole 180 through a brazing filler metal. Further, if necessary, a bottomed hole may be provided and a thermocouple may be embedded inside the hole. As the solder, an alloy such as silver-lead, lead-tin, 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 with solder.

In the above description, the wafer prober 101
Although the wafer prober 201 (see FIG. 5) is manufactured, the heating element may be printed on the green sheet. Further, when the wafer prober 301 (see FIG. 6) is manufactured, a metal plate as a guard electrode and a ground electrode in the ceramic powder, and a metal wire as a heating element may be embedded and sintered. Further, when the wafer prober 401 (see FIG. 7) is manufactured, the Peltier element may be joined via the sprayed metal layer.

[0078]

The present invention will be described in more detail below. (Example 1) Manufacture of wafer prober 101 (see FIG. 1) (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) 4 parts by weight, 1.0 part by weight of phenolic resin, and 53 parts by weight of alcohol consisting of 1-butanol and ethanol were mixed to obtain a mixture composition having a thickness of 0. A green sheet of 0.47 mm was obtained.

(2) Next, this green sheet is heated to 80 ° C.
After drying for 5 hours, a through hole for through hole for connecting the heating element and the external terminal pin was provided by punching.

(3) 100 parts by weight of tungsten carbide particles having an average particle size of 1 μm and an acrylic binder of 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 conductive paste A. Further, 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 were mixed to obtain a conductive paste B. .

Next, the grid-shaped print body for guard electrode 50 and the print body for ground electrode 60 were printed on the green sheet by screen printing using the conductive paste A. Further, the conductive paste B was filled in the through holes for through holes for connecting to the terminal pins.

Further, 50 printed green sheets and 50 unprinted green sheets are laminated to form 1
A laminated body was produced by integrating at 30 ° C. and a pressure of 80 kg / cm ² (see FIG. 10A).

(4) Next, this laminated body was subjected to 6 in nitrogen gas.
Degreasing at 00 ℃ for 5 hours, 1890 ℃, pressure 150kg /
It was hot-pressed at cm ² for 3 hours to obtain an aluminum nitride plate-shaped body having a thickness of 3 mm. The obtained plate-shaped body has a diameter of 230
A circular plate of mm was cut out to obtain a ceramic plate-like body (see FIG. 10B). The through holes 16 and 17 had a diameter of 0.2 mm and a depth of 0.2 mm. The thickness of the guard electrode 5 and the ground electrode 6 is 10 μm,
The formation position of the guard electrode 5 is 1 mm from the wafer mounting surface,
The formation position of the ground electrode 6 is 1.2 from the wafer mounting surface.
It was mm. The size of one side of the conductor non-formation area (square) of the guard electrode 5 and the ground electrode 6 is 0.5.
It was mm.

(5) After polishing the plate-like body obtained in (4) above with a diamond grindstone, a mask is placed on the surface and a blast treatment with SiC or the like is performed to form a concave portion (not shown) for the thermocouple on the surface. Further, a groove 7 (width 0.5 mm, depth 0.5 mm) for adsorbing the wafer was provided. (FIG.10 (c)).

(6) Further, the heating element 41 is printed on the surface facing the wafer mounting surface. The printing used conductive paste. The conductive paste is Solbest PS manufactured by Tokuriki Kagaku Kenkyusho, which is used for forming through holes in printed wiring boards.
603D was used. This conductive paste is a silver / lead paste, including lead oxide, zinc oxide, silica, boron oxide,
Metal oxide made of alumina (the weight ratio of each is
5/55/10/25/5) in an amount of 7.5 parts by weight based on 100 parts by weight of silver. Further, the silver had a scaly shape with an average particle size of 4.5 μm.

(7) The heater plate on which the conductive paste was printed was heated and baked at 780 ° C. to sinter silver and lead contained in the conductive paste and to bake it on the ceramic substrate 3. Further, the heater plate is dipped in an electroless nickel plating bath made of an aqueous solution containing 30 g / l of nickel sulfate, 30 g / l of boric acid, 30 g / l of ammonium chloride and 60 g / l of Rochelle salt, and the surface of the silver sintered body 41 is A nickel layer 410 having a thickness of 1 μm and a boron content of 1 wt% or less was deposited. Then, the heater plate was annealed at 120 ° C. for 3 hours. The heating element made of a silver sintered body has a thickness of 5 μm, a width of 2.4 mm, and an area resistivity of 7.7 m.
It was Ω / □ (Fig. 10 (d)).

(8) A titanium layer, a molybdenum layer, and a nickel layer were sequentially formed on the surface where the groove 7 was formed by a sputtering method. As an apparatus for sputtering, SV-4540 manufactured by Nippon Vacuum Technology Co., Ltd. was used. The conditions of sputtering were atmospheric pressure of 0.6 Pa, temperature of 100 ° C., and electric power of 200 W, and the sputtering time was adjusted within the range of 30 seconds to 1 minute by each metal. The thickness of the obtained film was 0. 0 for the titanium layer from the image of the fluorescent X-ray analyzer.
3 μm, the molybdenum layer was 2 μm, and the nickel layer was 1 μm.

(9) Nickel sulfate 30 g / l, boric acid 3
The surface of the metal layer formed by sputtering by immersing the ceramic plate obtained in (8) above in an electroless nickel plating bath consisting of an aqueous solution containing 0 g / l, ammonium chloride 30 g / l and Rochelle salt 60 g / l Then, a nickel layer having a thickness of 7 μm and a boron content of 1% by weight or less was deposited and annealed at 120 ° C. for 3 hours. The surface of the heating element does not carry an electric current and is not covered with electrolytic nickel plating.

Furthermore, potassium gold cyanide 2 g /
1, ammonium chloride 75 g / l, sodium citrate 50 g / l, and sodium hypophosphite 10 g / l in an electroless gold plating solution at 93 ° C. for 1 minute.
A gold plating layer having a thickness of 1 μm was formed on the nickel plating layer 15 (see FIG. 11 (e)).

(10) An air suction hole 8 extending from the groove 7 to the rear surface is formed by drilling, and the through hole 1 is further formed.
A bag hole 180 is provided to expose 6 and 17 (see FIG. 1).
0 (f)). Ni-Au alloy (A
u 81.5% by weight, Ni 18.4% by weight, impurities 0.1
(% By weight) was used to heat and reflow the solder at 970 ° C. to connect the external terminal pins 19 and 190 made of Kovar (see FIG. 11 (g)). Further, an external terminal pin 191 made of Kovar was 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 embedded in the recess to obtain the wafer prober heater 101.

(Comparative Example 1) In the process of (4), the laminate prepared by laminating green sheets was degreased at 300 ° C. for 6 hours in a nitrogen gas atmosphere containing oxygen. A wafer prober was manufactured in the same manner as in 1.

[0093]Evaluation methods (I) Measurement of carbon content Crush ceramic substrate into powder and heat to 800 ℃
Then, the carbon content is measured by measuring the amount of generated CO.
Numerous measurements were made. (Ii) Measurement of volume resistivity and thermal conductivity Cut out columnar samples from the manufactured wafer prober
Then, the volume resistivity at each temperature was measured by the three-terminal method.
The thermal conductivity was measured by the laser flash method.

(Iii) Measurement of lightness Lightness was measured according to JIS Z 8721. (iv) X-ray diffraction analysis A part of the ceramic substrate was sampled and pulverized, and the powder was subjected to X-ray diffraction analysis.

As a result, in the wafer prober according to Example 1, the carbon content was 800 ppm, and
As shown in the X-ray diffraction chart of the above, a clear carbon peak was recognized. In addition, JIS Z 8
Since the brightness based on 721 is N2, the amount of radiant heat was large when the ceramic substrate was heated using the heating element, and the concealing property of the internal guard electrode and the like was excellent. further,
Volume resistivity at 200 ° C is also 1.0 × 10 ¹² Ω · cm
It was high enough and there was no danger of dielectric breakdown. Also,
The thermal conductivity at 200 ° C. was 130 W / m · K.

On the other hand, in the wafer prober according to Comparative Example 1, the carbon content was 80 ppm, and
As shown in the line diffraction chart, no carbon peak was observed. Moreover, the volume resistance value at 200 ° C. was 1.2 × 10 ¹² Ω · cm, which was not a problem.
Since the brightness based on Z 8721 is N8.5, the internal guard electrode and the like were not hidden and the shape was visible. Further, the obtained ceramic substrate had color unevenness. Furthermore, the thermal conductivity is 120 W / m
It became as low as K.

[0097]

As described above, in the wafer prober of the present invention and the ceramic substrate used in the wafer prober, in the X-ray diffraction chart of the ceramic substrate,
A peak due to carbon can be recognized, so that it is sufficiently blackened, the guard electrode and the ground electrode can be concealed, and sufficient thermal conductivity and volume resistivity to function as a wafer prober are obtained. Can be secured.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing an example of a wafer prober of the present invention.

FIG. 2 is a plan view of the wafer prober shown in FIG.

FIG. 3 is a bottom view of the wafer prober shown in FIG.

4 is a cross-sectional view of the wafer prober shown in FIG. 1 taken along the line AA.

FIG. 5 is a sectional view schematically showing an example of the wafer prober of the present invention.

FIG. 6 is a sectional view schematically showing an example of the wafer prober of the present invention.

FIG. 7 is a sectional view schematically showing an example of the wafer prober of the present invention.

FIG. 8 is a sectional view schematically showing a case where the wafer prober of the present invention is combined with a support container.

9A is a vertical sectional view schematically showing a case where the wafer prober of the present invention is combined with another supporting container, and FIG. 9B is a sectional view taken along line BB thereof.

10 (a) to 10 (d) are cross-sectional views schematically showing a part of the manufacturing process of the wafer prober of the present invention.

11 (e) to (g) are cross-sectional views schematically showing a part of the manufacturing process of the wafer prober of the present invention.

FIG. 12 is a sectional view schematically showing a state in which a continuity test is performed using the wafer prober of the present invention.

FIG. 13 is an X-ray diffraction chart of a ceramic substrate made of aluminum nitride containing carbon.

FIG. 14 is an X-ray diffraction chart of a ceramic substrate made of aluminum nitride containing no carbon.

FIG. 15 is a graph schematically showing the relationship between temperature and volume resistivity of a ceramic substrate made of carbon-containing aluminum nitride.

FIG. 16 is a graph schematically showing the relationship between temperature and thermal conductivity of a ceramic substrate made of aluminum nitride containing carbon.

[Explanation of symbols]

101, 201, 301, 401 Wafer prober 2 Chuck top conductor layer 3 Ceramic substrate 5 Guard electrode 6 ground electrode 7 groove 8 suction port 10 Insulation 11 Support container 12 Refrigerant outlet 13 Suction port 14 Refrigerant inlet 15 Support pillars 16, 17, 18 through holes 180 bag holes 19, 190, 191 External terminal pin 41, 42 heating element 410 Protective layer 43 metal wire 44 Peltier element 440 thermoelectric element 441 ceramic substrate 51 conductor layer 52 Conductor layer non-formation part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasutaka Ito             1-1 Ibide, Northern Ibigawa-cho, Ibi-gun, Gifu Prefecture             Within the corporation F-term (reference) 2G003 AA10 AG04 AH07 AH08                 2G011 AA16 AB06 AB09 AB10 AC33                       AE03 AF07                 4M106 AA01 DD30 DJ02                 5F031 CA02 HA02 HA03 HA10 HA13                       HA37 HA38 MA33 PA13 PA26

Claims (4)

[Claims] 1. A wafer prober in which a chuck top conductor layer is formed on the surface of a ceramic substrate, wherein in the X-ray diffraction chart of the ceramic substrate, X-rays are present in addition to the peaks of the ceramics constituting the main crystal phase. Diffraction angle 2
A wafer prober, wherein a carbon peak is detected at θ = 44 to 45 °. 2. The wafer prober according to claim 1, wherein the ceramic substrate is mainly composed of aluminum nitride. 3. A ceramic substrate having a chuck top conductor layer formed on the surface thereof, wherein in the X-ray diffraction chart of the ceramic substrate, in addition to the peak of the ceramic constituting the main crystal phase, the X-ray diffraction angle 2θ = 44 to 4
A ceramic substrate used in a wafer prober having a carbon peak detected at 5 °. 4. A ceramic substrate for use in a wafer prober according to claim 3, wherein the main component is aluminum nitride.