JP2010083749A - Free-cutting ceramic composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a free-cutting ceramic composite material exhibiting excellent free-cutting property, high bending strength and Young's modulus and excellent machinability. <P>SOLUTION: Provided is the free-cutting ceramic composite material having hexagonal boron nitride (h-BN) contained in the grain boundary of a matrix composed of ceramic particles, wherein the maximum particle diameter of the h-BN existing in the free-cutting ceramic composite material is <22 μm, and the standard deviation of area ratio when the quantity of the h-BN existing in the grain boundary in the free-cutting ceramic composite material is measured is ≤0.15, so that the free-cutting ceramic composite material exhibiting excellent free-cutting property, high bending strength and Young's modulus and developing excellent machinability is obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  Aspects of the present invention generally relate to a free-cutting ceramic composite material having excellent free-cutting properties and mechanical properties.

Machinable ceramics are known as materials for components of precision equipment and semiconductor manufacturing / inspection equipment. As these machinable ceramics, h-BN dispersed in a matrix of AlN, Si ₃ N4, and ZrO ₂ is pleasant. Excellent machinability and mechanical thermal properties. As prior arts of this machinable ceramic, those listed in Patent Documents 1, 2, and 3 are known.

In Patent Document 1, as a method for manufacturing a machinable ceramic, ZrO ₂ , BN, Si ₃ N ₄ , and a sintering aid (Al ₂ O ₃ , Y ₂ O _3, etc.) are wet-mixed and dried. It is disclosed that the powder is fired at 30 MPa in a nitrogen atmosphere at 1600 ° C. for 2 hours. Since a large amount of BN is added, it is excellent in free-cutting properties but inferior in mechanical properties such as bending strength and Young's modulus.

Patent Document 2 discloses a sintered body in which h-BN having a particle size of 80 nm or less is uniformly dispersed in a crystal grain of AlN, Si ₃ N ₄ , or sialon or a crystal grain boundary. It is characterized by using nanoparticles with a particle size of h-BN of 80 nm or less and uniformly dispersed, and mechanical properties are superior to those using conventional micrometer-sized h-BN. High hardness causes tool wear and poor workability. In addition, urea and boric acid are mixed into the matrix raw material powder and heat treated to precipitate the fine primary particles of h-BN on the matrix raw material powder. Is difficult and not an industrially applicable technology.

Patent Document 3 discloses that a machinable ceramic is produced by wet-mixing ZrO ₂ , h-BN, and ZrSiO ₄ , and firing the dried powder in a nitrogen atmosphere using a hot press. .
JP 2005-119941 Japanese Patent No. 3567884 JP 2008-24530 A

  As material properties of components of precision equipment and semiconductor manufacturing / inspection equipment, free-cutting ceramic materials with higher strength and Young's modulus than conventional products are required as materials become larger and processing becomes finer. Among them, the probe card die, which is a probe guide member, is subjected to hole processing of micrometer size in the material, but the hole diameter is reduced, and the pitch and thickness are reduced.

  In addition, probe card dies are becoming larger in accordance with inspection efficiency, and higher strength, Young's modulus, and excellent processing accuracy are required than ever. In order to satisfy these requirements, the above materials have problems in mechanical properties and workability.

  An aspect of the present invention is to provide a free-cutting ceramic composite material that exhibits free-cutting properties, high bending strength, Young's modulus, and excellent processing accuracy.

  In order to achieve the above object, in one embodiment of the present invention, there is provided a free-cutting ceramic composite material in which h-BN is present at a grain boundary of a matrix composed of ceramic particles, and the free-cutting ceramic A free-cutting ceramic composite material characterized in that the maximum particle size of h-BN present in the composite material is less than 22 μm, the Young's modulus is 150 GPa or more, and the three-point bending strength is 280 MPa or more. it can.

  In a preferred embodiment of the present invention, the free-cutting ceramic composite material has a standard deviation of the area ratio of 0.15 or less when the amount of h-BN existing at grain boundaries in the free-cutting ceramic composite material is measured. Can do.

In a preferred embodiment of the present invention, there is provided a free-cutting ceramic composite material obtained by firing in a non-oxidizing atmosphere containing (a) ZrO ₂ , Al ₂ O ₃ , or ZrSiO ₄ , and (b) h-BN. The content of the component (b) in the composite material is 5 to 40 vol%, the component (a) forms a matrix by a sintering reaction, and the component (b) It is possible to obtain a free-cutting ceramic composite material which exists at the grain boundary of component a) and has an average particle diameter of component (b) of 0.1 to 21 μm.

In a preferred embodiment of the present invention, a free-cutting ceramic composite material further added with Si ₃ N ₄ or ZrO ₂ can be obtained.

  The probe guide component according to the present invention is a probe guide component having a plurality of through holes through which a probe passes, and can be a probe guide component including a free-cutting ceramic composite material according to an embodiment of the present invention.

  According to the aspect of the present invention, it is possible to provide a free-cutting ceramic composite material that exhibits free-cutting properties, high bending strength, Young's modulus, and excellent processing accuracy.

It is a figure which shows the SEM image after the hole processing of the ceramic composite material by one Example of this invention. It is a figure which shows the SEM image after the hole processing of the ceramic composite material shown in the comparative example 1. FIG.

The words used in this case are explained below.
(Particle size of h-BN)
The SEM image is binarized and the particle size of each h-BN is calculated. The particle size is defined as the particle size of h-BN, where the area of h-BN is the area of a circle, the diameter is calculated from the area of the circle.
(H-BN cumulative 50% particle size)
The particle diameter when the cumulative number reaches 50% of the total number, based on the number of h-BN.
(Cumulative 90% particle size of h-BN)
The particle size when the cumulative number reaches 90% of the total number, based on the number of h-BN.
(H-BN area ratio)
The area of h-BN is obtained by binarizing the SEM image and calculating and integrating the area of each h-BN. The ratio of the area of the accumulated h-BN in the binarized image of the SEM image is defined as the area ratio.
(Standard deviation of h-BN area ratio)
The area of h-BN is obtained by binarizing the SEM image and calculating and integrating the area of each h-BN. The ratio of the integrated h-BN area in the binarized image of the SEM image was defined as the area ratio, and several area ratios were calculated to obtain the standard deviation.
(Hole position accuracy)
The hole position accuracy is defined as the average value of the position error from the center position of the back surface hole of the hole processed substrate and the set reference hole position plus 3 times the standard deviation of the position error.
(Narrow pitch)
The probe guide component is a component that guides a pin for conducting a continuity test of the semiconductor device, and a number of holes are processed. The distance between the centers of two adjacent holes is called the pitch. The narrowing of the pitch is called a narrow pitch.
(Thinning)
As the hole diameter does not change and the pitch becomes narrower, the thickness of the two adjacent holes becomes thinner. This is called thinning.
As the probe guide parts become narrower and thinner, the materials used for the probe guide parts are required to have high bending strength, Young's modulus, and excellent processing accuracy.

In one embodiment of the present invention, there is a free-cutting ceramic composite material in which h-BN exists in the grain boundary of a matrix composed of ceramic particles, and the h-BN present in the free-cutting ceramic composite material The free-cutting ceramic composite material has a maximum particle size of less than 22 μm, a Young's modulus of 150 GPa or more, and a three-point bending strength of 280 MPa or more. This makes it possible to produce machinable ceramics that are superior in quality.
If the Young's modulus is less than 150 GPa, the probe may bend due to the stress applied to the probe guide component by the probe, and the position accuracy may be deteriorated.
If the three-point bending strength is less than 280 MPa, the hole of the probe guide part and the thick part of the hole may be damaged when the substrate is thin and the pitch is narrowed.

  In a preferred embodiment of the present invention, the free-cutting ceramic composite material has a standard deviation of the area ratio of 0.15 or less when the amount of h-BN existing at grain boundaries in the free-cutting ceramic composite material is measured. This makes it possible to produce machinable ceramics with excellent workability and mechanical properties. In addition, by reducing the average particle size of h-BN, the bending strength is improved, and h-BN is present at the grain boundaries in the matrix so that the standard deviation of the h-BN area ratio is 0.15 or less. As a result, it becomes possible to produce a free-cutting ceramic composite material that is superior in processing accuracy.

In one embodiment of the present invention, a free-cutting ceramic composite material obtained by firing in a non-oxidizing atmosphere containing (a) ZrO ₂ , Al ₂ O ₃ , or ZrSiO ₄ , and (b) h-BN. The content of the component (b) in the composite material is 5 to 40 vol%, the component (a) forms a matrix by a sintering reaction, and the component (b) (A) A machinable ceramic having excellent workability and mechanical properties by being a free-cutting ceramic composite material present at the grain boundary of the component and having an average particle size of the component (b) of 0.1 to 21 μm. Fabrication was possible.

In a preferred embodiment of the present invention, a machinable ceramic having excellent workability and mechanical properties can be produced by using a free-cutting ceramic composite material to which Si ₃ N ₄ or ZrO ₂ is further added. did.

The probe guide component according to the present invention is a probe guide component having a plurality of through holes through which a probe passes, and can be a probe guide component including a free-cutting ceramic composite material according to an embodiment of the present invention.
The probe guide parts are also enlarged with the increase in the size of silicon wafers and the inspection efficiency of semiconductor devices. In addition, semiconductor devices are highly integrated, and the pin diameter of the probe guide component is small and the number is large, and the pitch is reduced and the thickness is reduced.
The free-cutting ceramic composite material according to one embodiment of the present invention has high bending strength, Young's modulus, and excellent processing accuracy, and therefore can satisfy the above-described performance required for probe guide parts.

  Details of one embodiment of the present invention will be described below.

  In one embodiment of the present invention, the amount of h-BN present at the grain boundaries of the matrix particles is 20 to 40 vol%.

  The average particle diameter of h-BN is 0.1-21 μm, preferably 0.1-9 μm. More preferably, it is 0.1-6 micrometers. Since h-BN has low strength, the effect of h-BN particle size on strength is large when composite materials are used. Therefore, if the average particle size of h-BN is small, a decrease in strength can be suppressed.

  The standard deviation of the area ratio of h-BN is 0.15 or less, preferably 0.1 or less. More preferably, it is 0.05 or less. The standard deviation of the area ratio of h-BN indicates the dispersibility of h-BN. If the standard deviation is low, the machining accuracy is improved and stable machining is possible.

  By making h-BN present in the grain boundaries of the matrix particles, the decrease in mechanical properties is suppressed, and free-cutting properties and excellent processing accuracy are exhibited. When the amount of h-BN exceeds the above upper limit, the ceramic composite material is excellent in free-cutting properties, but mechanical properties such as bending strength and Young's modulus are lowered. On the other hand, if the amount of h-BN is less than the above lower limit value, the mechanical property value is excellent, but the effect of free-cutting property is not preferable.

  A method for calculating the standard deviation of the particle size and area ratio of h-BN present in the matrix particles will be described in detail.

  The produced fired body is cut into a specimen for observation, and the surface is lapped with 1 to 3 μm abrasive grains to give a mirror surface. The lapped specimen is observed with a scanning electron microscope (SEM). The observation magnification is preferably 1000 to 3000 times. It is also desirable to take a backscattered electron image rather than a secondary electron image in order to obtain a contrast between matrix particles and h-BN particles. The captured image is trimmed to remove unnecessary portions using image processing software, and median filter processing is performed to reduce image noise. Adjust the brightness and contrast of the image and perform binarization. The particle diameter and particle area of h-BN were calculated from the binarized image using particle image analysis software. This process was performed on a plurality of sites.

  The processing accuracy evaluation method will be described in detail.

  A machining sample was fixed on the stage, and a flat drill made of sintered diamond with a diameter of 40 μm made by wire electric discharge machining was attached to a machining center or the like, and 300 holes were drilled. As a sintered diamond for self-made flat drills, TDC-GM (average particle size 3 μm) manufactured by Tomei Diamond was used. The hole on the back surface of the processing sample was observed with an optical microscope, image processing was performed, and the hole position accuracy was measured.

  Various physical property values will be described in detail.

The Young's modulus is measured by a resonance method, and the number of measurements is 3, which is an average value.
The bending strength is measured by a three-point bending test, and the number of measurements is an average value of 5 to 10.
The coefficient of thermal expansion is measured from room temperature to 200 ° C. using a differential thermal dilatometer, and the number of measurements is 2, which is an average value.

  The Vickers hardness was measured with a load of 2.5 kg for 15 s using a Vickers hardness tester. The number of measurements is 30, which is an average value.

The meaning of the physical property values will be described in detail.
Probe guide members are becoming larger and more integrated, and a high Young's modulus is required. If the Young's modulus is less than 100 GPa, the position accuracy error may be affected by the effect of deflection due to stress on the member.

  Due to the high integration of the probe guide members, the distance between the holes is reduced and the thickness is reduced. Therefore, a high strength of 300 MPa or more is required. More preferably, it is 350 MPa or more.

With the increase in size, high integration, and high temperature testing of probe guide members, the probe position error due to thermal expansion of the members cannot be ignored. Therefore, a thermal expansion coefficient close to that of silicon (3.9 × 10 ⁻⁶ / K) is required. In the high temperature test, the silicon wafer is in contact with the heater, and since the probe guide member is on the heater, the temperature of the probe guide member is slightly lower than that of the silicon wafer. Therefore, the thermal expansion coefficient is preferably 3.9 to 5.0 × 10 ⁻⁶ / K.

  Hereinafter, a method for producing the free-cutting ceramic composite material of the present invention will be described in detail.

  The free-cutting ceramic composite material of the present invention is obtained by wet-mixing h-BN and raw material powders that form matrix particles, drying them, and sintering them by hot pressing.

Here, h-BN having a primary particle diameter of 0.1 μm or more and less than 1 μm is suitable for the raw material powder that becomes h-BN and matrix particles. If it exceeds 1 μm, the sinterability is deteriorated, and if it is less than 0.1 μm, the hardness increases and the workability may be deteriorated. The primary particle size of h-BN is measured by SEM image.
The matrix particles preferably have a cumulative 50% particle size of less than 1 μm. The method for measuring the particle size of the matrix particle material is performed by laser diffraction, and the cumulative 50% particle size is the volume average diameter.
It is preferable to use stabilized ZrO ₂ as matrix particles. When a free-cutting ceramic composite material is produced using partially stabilized ZrO ₂ and this material is used at a high temperature of 100 ° C. or higher, phase transformation may occur and the hole position accuracy may deteriorate.

These raw materials are wet-mixed with a ball mill or the like and granulated with a spray dryer or the like. This is packed in a graphite mold and sintered by hot pressing. The atmosphere is an inert or neutral atmosphere. The hot pressing temperature is in the range of 1400-1800 ° C. If the temperature is too low, sintering becomes insufficient and excellent physical properties are not exhibited. If the temperature is too high, ZrSiO ₄ is decomposed or ZrO ₂ or Al ₂ O ₃ grows. The pressing force is in the range of 10 to 50 MPa, and the holding time at the maximum temperature of the hot press is suitably 1 to 4 hours depending on the dimensions.

  This free-cutting ceramic composite material is excellent in free-cutting property and processing accuracy, has high strength and high Young's modulus, and has a thermal expansion coefficient close to that of silicon. In addition, by reducing the particle size of h-BN and reducing the standard deviation of the area ratio, the processing accuracy is greatly improved, and the probe guide member used in the semiconductor inspection equipment is highly integrated in the semiconductor and the inspection efficiency is improved. With the improvement, the size is increased and the hole diameter and the hole interval are also reduced, but it can be adequately accommodated.

  The free-cutting ceramic composite material according to one embodiment of the present invention is excellent in free-cutting property and processing accuracy, has a high Young's modulus and bending strength, and has a thermal expansion coefficient close to silicon and low thermal expansion at room temperature to 200 ° C. Therefore, it is suitable as a member for a probe card which has recently been highly integrated, has a small hole interval, has a thin wall thickness, and has a strong demand for collective inspection.

  Embodiments of the present invention will be described below.

Raw material powder composed of ZrSiO ₄ , ZrO ₂ , h-BN is wet-mixed by ball mill and bead mill, dried, sintered by hot pressing or nitrogen atmosphere, and sintered by hot isostatic pressing (HIP) Get.

  Test pieces for measuring physical properties were cut out from the ceramic sintered body, and the Young's modulus was measured by a resonance method and the bending strength was measured by a three-point bending test. Furthermore, the thermal expansion coefficient of this sintered body was measured at room temperature (25 ° C.) to 200 ° C.

  In order to evaluate the processing accuracy, a processing sample was fixed on the stage, a self-made flat drill made of sintered diamond of φ40μm was attached to the machining center, drill rotation speed 15000rpm, cutting depth 2.5μm / step, feed rate 3.0mm / min 300 holes were drilled. The hole on the back surface of the processing sample was observed with an optical microscope, image processing was performed, and the hole position accuracy was measured.

  Further, the fired body thus produced is cut into an observation test piece, and the surface is lapped with 1 μm abrasive grains to give a mirror surface. The lapped specimen is observed with a scanning electron microscope (SEM). The observation magnification is 1000 times.

  A backscattered electron image was taken to obtain a contrast between matrix particles and h-BN particles. The captured image is processed using image processing software (multifunctional integrated image viewer ViX), trimmed to remove unnecessary portions, and median filter processing is performed using image processing software (PaintShopPro4) to reduce image noise. It was. Adjust the brightness and contrast of the image and perform binarization. The particle diameter and particle area of h-BN were calculated using particle image analysis software produced by binarized images. The resolution of the particle image analysis software is 0.155 μm / pixel. This process was performed for nine locations.

(Examples 1-5)
First, three types of materials, ZrSiO4, ZrO2, and h-BN, were used as raw materials. Cumulative 50% particle diameters were 0.9 μm and 0.35 μm, respectively, and h-BN had a primary particle diameter of 0.1 to 1 μm.

  The raw materials were mixed so that the raw materials were 45 vol%, 25 vol%, and 30 vol%, respectively, and wet mixed for 2 to 96 hours using a ball mill or bead mill. The solvent is an organic solvent such as ethanol or ion-exchanged water. When ion-exchanged water is used as a solvent, a wetting agent and a dispersant are added because h-BN is difficult to wet with water. The wet mixture was dried to obtain a raw material powder.

  This raw material powder is filled into a graphite die, and sintered by hot pressing at 1450-1550 ° C for 1-4 hours while applying a pressure of 40 MPa in a nitrogen atmosphere to obtain a ceramic composite material of 50 mm square and 10 mm thickness. It was.

(Examples 6 to 11)
First, three types of materials, ZrSiO4, ZrO2, and h-BN, were used as raw materials. Cumulative 50% particle diameters were 0.9 μm and 0.35 μm, respectively, and h-BN had a primary particle diameter of 0.1 to 1 μm.

  The raw materials were mixed so that the raw materials were 65 vol%, 15 vol%, and 20 vol%, respectively, and wet mixed by a ball mill or bead mill for 1 to 96 hours. The solvent is an organic solvent such as ethanol or ion-exchanged water. When ion-exchanged water is used as a solvent, a wetting agent and a dispersant are added because h-BN is difficult to wet with water. The wet mixture was dried to obtain a raw material powder.

  This raw material powder is filled into a graphite die, and sintered by hot pressing at 1450-1550 ° C for 1-4 hours while applying a pressure of 40 MPa in a nitrogen atmosphere to obtain a ceramic composite material of 50 mm square and 10 mm thickness. It was.

(Examples 12 to 15)
First, _three materials, Si ₃ N ₄ , ZrO 2 and h-BN, were used as raw materials. Cumulative 50% particle sizes were 1 μm and 0.35 μm, respectively, and h-BN had a primary particle size of 0.1 to 1 μm.

  The raw materials were mixed so that the raw materials were 25 vol%, 45 vol%, and 30 vol%, respectively, and wet-mixed for 1 to 96 hours using a ball mill or bead mill. The solvent is an organic solvent such as ethanol or ion-exchanged water. When ion-exchanged water is used as a solvent, a wetting agent and a dispersant are added because h-BN is difficult to wet with water. The wet mixture was dried to obtain a raw material powder.

  This raw material powder is filled into a graphite die, and sintered by hot pressing at 1450-1550 ° C for 1-4 hours while applying a pressure of 40 MPa in a nitrogen atmosphere to obtain a ceramic composite material of 50 mm square and 10 mm thickness. It was.

  Table 1 shows the particle size distribution of h-BN calculated by image processing of the free-cutting ceramic composite material produced. In Comparative Example 1, since the BN contained a large amount of 60 vol% to form a matrix, the particle size distribution and area ratio of h-BN were not calculated.

  Table 2 shows the standard deviation of h-BN area ratio and machining accuracy.

  Table 3 shows the measured values of physical properties of the free-cutting ceramic composite material produced.

From Table 1 and Table 2, in Example 1, the particle size of h-BN is 0.1 to 21 μm, and the hole position accuracy is in the range of less than 5 μm, which is good. In Example 4, the particle size of h-BN is 0.1-9 μm, and the hole position accuracy is in the range of less than 2 μm, which is good. Furthermore, in Example 5, the particle diameter of h-BN is 0.1 to 6 μm, and the hole position accuracy is in the range of less than 1 μm, which is very good.
In Examples 10, 11, 14, and 15, the particle size of h-BN is 0.1 to 21 μm, and the hole position accuracy is in the range of less than 5 μm, which is good. In Examples 6 to 9, 12, and 13, the particle size of h-BN is 0.1 to 6 μm, and the hole position accuracy is in the range of less than 2 μm, which is good.

From Tables 2 and 3, Examples 1 to 15 exhibit high Young's modulus while maintaining good hole position accuracy. In Examples 4, 5, 6 to 9, 12, and 13, the bending strength is improved because the particle size of h-BN is small. Although the hole position accuracy of Comparative Example 1 is good, the bending strength and Young's modulus are low due to the large amount of BN added.
The maximum particle diameter of a preferable h-BN particle for exhibiting high bending strength and Young's modulus is less than 17 μm, and the standard deviation of the preferred h-BN area ratio is less than 0.06.

  FIG. 1 shows an SEM image after drilling a ceramic composite material according to an embodiment of the present invention. FIG. 2 shows an SEM image of the ceramic composite material shown in Comparative Example 1 after drilling. Both are in good condition with no chipping, but the surface of the ceramic composite material shown in Comparative Example 1 is rough because BN is added in a large amount. For this reason, there is a possibility of wear due to a decrease in bending strength or sliding between the probe guide component and the inspection pin.

The embodiments are merely examples of the invention and can be applied as appropriate.

  The free-cutting ceramic composite material according to an embodiment of the present invention can be used as a probe card for inspecting the continuity of a semiconductor element such as an IC or LSI.

Claims (5)

This is a free-cutting ceramic composite material in which h-BN exists at the grain boundaries of the matrix composed of ceramic particles, and the maximum particle size of h-BN existing in the free-cutting ceramic composite material is less than 22μm. A free-cutting ceramic composite material having a Young's modulus of 150 GPa or more and a three-point bending strength of 280 MPa or more. 2. The free-cutting ceramic composite material according to claim 1, wherein the standard deviation of the area ratio when measuring the amount of h-BN existing at grain boundaries in the free-cutting ceramic composite material is 0.15 or less. . The free-cutting ceramic composite material is obtained by firing in a non-oxidizing atmosphere containing (a) any one or more of ZrO ₂ , Al ₂ O ₃ , or ZrSiO ₄ and (b) h-BN, The content of the component (b) in the composite material is 20 to 40 vol%, the component (a) forms a matrix by a sintering reaction, and the component (b) is the component (a) 3. The free-cutting ceramic composite material according to claim 1, wherein the free-cutting ceramic composite material is present at a grain boundary of the component, and a cumulative 50% particle size of the component (b) is 0.5 to 2 μm. The free-cutting ceramic composite material according to claim 3, further comprising Si ₃ N ₄ or ZrO ₂ added thereto. A probe guide component having a plurality of through-holes through which the probe passes, comprising the free-cutting ceramic composite material according to any one of claims 1 to 4.

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