JPH04230904A - Electrification removing ceramic and manufacturing composite material thereof - Google Patents

Abstract

PURPOSE:To obtain useful ceramic for eliminating electrification in handling electronic parts by realizing a raw material with the surface resistivity 10<6>-10<10>OMEGA/cm<2> from composite ceramic. CONSTITUTION:Electrification removing ceramic contains one or more kinds of conducting compound 4-23vol.% selected among nitrides and carbides of Ti, Zr, Hf, Nb in the matrix mainly made of alumina. The powder mixture of the manufacturing composition material has the power average grain size of 5mum or below.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ceramics for removing static charge and compositions for producing the same, which can prevent destruction of electronic parts when they are charged and discharged.

0002

2. Description of the Related Art In the manufacture of electronic components, it has become an important issue to take measures to prevent components from being destroyed due to discharge of charge from charged components. That is, when a conductive material such as a metal with low electrical resistance comes into contact with a component such as a semiconductor device that is charged by actual charging or induction charging, the component is often destroyed by rapid discharge.

For example, with a commonly available electrical insulating material having a specific resistance on the order of 10 13 Ωcm, charge cannot be removed effectively because the discharge of charge does not proceed effectively. The sheet resistivity that meets this purpose is 105 to 1010Ω/cm2.
Although it is said that the resistivity is within this range, there is no suitable material with a single composition that exhibits a sheet resistivity in this range.

[0004] For this reason, there has been a long-awaited development of a new material having an appropriate sheet resistivity, which would not destroy electrically charged parts when handling electronic parts, and would allow the charge to be quickly removed.

[0005]

[Problems to be Solved by the Invention] The present invention aims to realize a material having a required level of sheet resistivity using composite ceramics, and to provide ceramics useful for removing static electricity. .

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the charge removing ceramic of the present invention has Ti, Zr,
It is characterized by containing one or more conductive compounds selected from nitrides and carbides of Hf, Nb or Ta, and having a sheet resistivity in the range of 106 to 1010 Ω/cm2.

[0007] Here, it is possible to obtain a desired level of sheet resistivity by combining specific metal nitrides and carbides, which are conductive ceramic components, and alumina, which is an insulating ceramic. Became.

That is, by setting the sheet resistivity of this ceramic to 106 Ω/cm2 or more, discharge when removing static electricity can be performed slowly without generating sparks, and by setting the sheet resistivity to 1010 Ω/cm2 or less, discharge can be performed slowly without generating sparks. By doing so, it is possible to obtain a ceramic for charge removal that can perform charge removal reliably.

[0009] The composition for producing a ceramic for charge removal according to the present invention contains a total of 4 to 23 volumes of one or more conductive compounds selected from nitrides and carbides of Ti, Zr, Hf, Nb, or Ta. %, with the remainder consisting essentially of alumina powder, and is characterized in that the average particle size of both the conductive compound powder and the alumina powder is 5 μm or less.

If the average particle diameter of the powder is coarser than 5 μm, it becomes difficult to obtain the desired sheet resistivity, and at the same time, the densification of the sintered body does not proceed sufficiently, resulting in insufficient strength, unevenness, and generation of dust due to wear. yields no results.

[0011] In the charge removal ceramic of the present invention, alumina (specific resistance > 1013 Ωcm), which is an insulating ceramic having excellent strength, wear resistance, and heat resistance, is combined with
Ti, Zr, Hf, which are ceramics with conductivity
, 1 selected from nitrides and carbides of Nb and Ta
Compound with conductivity of 10-6 to 1
0-10 Ω/cm), the sheet resistivity of the sintered body is controlled to an appropriate range of 10 6 to 10 10 Ω/cm 2 , and the sintered body has sufficient density and strength.

[0012] In order to produce this charge-removing ceramic, T
i, Zr, Hf, Nb and Ta nitrides and carbides in total of 4~
A mixed composition containing 23% by volume and the remainder being alumina powder with an average particle size of 5 μm or less may be used as a starting material, and may be molded and sintered by a conventional method.

[0013] Commercially available powders can be used as these powder raw materials, and the conductive compound powder and alumina powder are pulverized if necessary, and both are used with an average particle size of 5 μm or less. Particle size is 0.1~2μm
It is preferable to use

[0014] The alumina powder and the conductive ceramic powder are mixed by a process using a rotary ball mill or a vibration mill, which are usually used in the production of ceramics, an attrition mill process for the suspension, and a stirring process for the suspension using a stirrer. These methods can be used as they are, but in order to obtain a uniformly dispersed powder, it is preferable to use a wet rotary ball mill, an attrition mill, or the like using a solvent such as alcohol.

Magnesia (
It is common practice to add fine powder of MgO), but even if magnesia is added in an amount of about 1000 ppm, there is no particular problem such as deterioration of the properties as a ceramic for strip removal.

[0016] In order to mold the powder that is the composition for producing ceramics for removing static electricity of the present invention into a desired shape, press methods, slip casting methods, injection molding methods, etc. that are commonly used for molding ceramics can be used. . However, since molded articles produced by injection molding usually contain a large amount of binder component, it is necessary to carry out degreasing treatment in air at a temperature of about 500° C. over a long period of time prior to firing.

[0017] In order to sinter the molded body thus obtained,
The process is carried out in a non-oxidizing atmosphere to prevent the conductive ceramic powder from being oxidized. As a sintering method, a hot press method, a pressureless sintering method, etc. can be used, but it is convenient to use a pressureless sintering method to obtain a sintered body having a complicated shape.

In this case, in order to obtain a more dense sintered body, hot isostatic pressure sintering (HIP) is preferably performed after atmospheric pressure sintering. In order to create a non-oxidizing atmosphere in the furnace, a gas such as nitrogen, argon, helium, etc. is introduced into the furnace, and the sintering temperature is set at 1550 to 1700°C in normal pressure sintering. It is preferable to hold and sinter for ~5 hours.

[0019]

[Examples] The present invention will be further explained below with reference to Examples, but the Examples are merely examples of the present invention and are not intended to limit the present invention in any way.

[0020] Average particle size 0.26 μm, purity 99.99
% alumina powder (AKP-5 manufactured by Sumitomo Chemical Co., Ltd.)
0), the average particle size is 1 to 2 μm, and the purity is about 99%.
selected from titanium nitride, zirconium nitride, titanium carbide, zirconium carbide (all manufactured by Stark Industries), hafnium nitride, hafnium carbide, niobium nitride, niobium carbide, tantalum nitride, tantalum carbide (all manufactured by Nippon Shinkinzoku Co., Ltd.) The powders were mixed at a ratio of 1 to 30% by volume as shown in Table 1, Table 2, Table 5, and Table 6, and wet-processed using ethyl alcohol as a medium using a vibrating mill consisting of a nylon pot and a nylon ball. Mixing was done.

The obtained slurry was dried under reduced pressure at about 60° C. to remove the alcohol content, and the dried product was crushed to obtain a powdered composition for producing ceramics. This composition was press-molded at 100 kg/cm2 using a mold press,
A molded body with dimensions of 50 mm x 120 mm x 10 mm was prepared, and further subjected to isostatic pressing at a pressure of 2000 kg/cm2.

[0022] This molded body was fired at 1550 to 1700°C for 3 hours in a non-oxidizing atmosphere of nitrogen or argon to obtain a dense sintered body. From these sintered bodies, 30
A flat plate of mm x 30 mm x 2 mm was cut out and the sheet resistivity of each was measured.
Five test pieces each measuring m x 4 mm x 40 mm were cut out and the three-point bending strength was measured.

In addition, for static elimination and discharge tests, each cut out test piece was joined to the tip of a metal rod by brazing, and the tip of the test piece was brought into contact with a lead wire connected to a pre-charged metal plate. The static elimination and discharge phenomena were observed, and the characteristics as a ceramic for static elimination were evaluated. These results, including the density of the sintered bodies, are shown in Tables 3, 4, 7 and 8.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

[0028]

[Table 5]

[0029]

[Table 6]

[0030]

[Table 7]

[0031]

[Table 8]

From the above test results, all of the ceramic sintered bodies produced using the composition of the present invention have a 106
It had a sheet resistivity in the range of ~1010 Ω/cm2, and exhibited effective static elimination properties as a ceramic for static elimination.

[0033] Also, the bending strength is 27 to 39 kgf/mm.
A value as high as 2 was obtained, indicating that the ceramic of the present invention is excellent as a material for removing electrical charges from handling electronic parts and the like.

[0034]

[Effects of the Invention] The ceramic for removing static electricity of the present invention can be used to remove static electricity generated when handling parts in the manufacture of electronic parts, etc.
It has a remarkable effect in preventing circuit destruction due to rapid discharge of charged charges.

[0035] For example, when picking up electronic parts, etc., by using the charge-removing ceramic of the present invention in the part that comes into direct contact with the electronic parts, the electric charge of the charged parts can be quickly removed without causing sparks or the like. This prevents circuit damage and contributes to improving the reliability of manufacturing equipment as well as the yield of parts.

[0036] Furthermore, since the charge removing ceramic of the present invention has high density and high strength, it hardly breaks or wears even when used in parts that come into direct contact with electronic parts, etc., and does not emit dust into the atmosphere. No worries.

Claims (2)

[Claims] 1. A matrix containing alumina as a main component contains one or more conductive compounds selected from nitrides and carbides of Ti, Zr, Hf, Nb or Ta,
A ceramic for charge removal, characterized in that the sheet resistivity is in the range of 10 6 to 10 10 Ω/cm 2 . 2. Contains a total of 4 to 23% by volume of powder of one or more conductive compounds selected from nitrides and carbides of Ti, Zr, Hf, Nb, or Ta, and the remainder is substantially alumina powder. 1. A composition for producing ceramics for charge removal, characterized in that the conductive compound powder and the alumina powder each have an average particle size of 5 μm or less.