JPH10235566A - Holding tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent conducting short-circuit and eliminate static electricity by supporting a tip member formed of ceramics of specified volume specific resistance and forming a supporting member performing a clamping operation by a material having specified volume specific resistance. SOLUTION: A holding tool is made b forming a pair of tip members 1 out of ceramics of volume specific resistance 10<3> to 10<9> Ω.cm, joining the rear end of this tip member 1 to a supporting member 2 of volume specific resistance 10<11> to 10<16> Ω.cm with an adhesive, etc., and supporting the rear end of this supporting member 2 by an elastic engaging body 3. By performing a clamping operation by hand, the elastic engaging body 3 elastically deforms and an object is held between the tip members 1, 1 at the tip. When volume specific resistance of the tip member 1 is less than 10<3> Ω.cm, little effect in prevention of short- circuit is produced. When volume specific resistance exceeds 10<9> Ω.cm, the efficiency of removing static electricity is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holding device such as a pair of tweezers made of a ceramic material used for handling components such as a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, for example, a clamp for handling a component such as a semiconductor device has been integrally formed of metal such as stainless steel or synthetic resin such as vinyl chloride. However, since metal-made holding devices have conductivity, there are problems such as poor handling accidents due to conduction short-circuits and poor inclusion of foreign matter due to metal dents.Synthetic resin holding devices have low heat resistance, corrosion resistance, etc. There was a problem that static electricity was hard to escape.

In order to improve heat resistance, corrosion resistance, insulation and the like, the present applicant has proposed a holding device using ceramics such as zirconia (Japanese Patent Publication No. 4-45300).
In recent years, it has been widely used.

[0004] By the way, in such a holding device made of ceramics, since the volume resistivity is high, it is possible to prevent a conduction short circuit, but there is a problem that it is difficult to release generated static electricity.

Therefore, the applicant of the present application has proposed that the volume resistivity is 10 ² to 10 ⁶ Ω · c so that static electricity can be easily removed.
A holding tool having a holding portion formed of ceramics having a low m is proposed (see Japanese Utility Model Publication No. 5-2303). For the same purpose, a clamp using a carbon composite material having a low volume resistivity has been used in order to easily remove static electricity.

[0006]

However, in the case of a clamping device in which the clamping portion is formed of ceramics having a low volume resistivity or a clamping device using a carbon composite material, inconvenience occurs because static electricity is removed at a stretch. I found that there was.

That is, as a property of static electricity, if it is removed at a stretch, it may cause an ultrahigh voltage discharge action due to atmospheric friction, and as a result, it may adversely affect the sandwiched electronic components and the like.

[0008] In addition, in the holding tool using the carbon synthetic material, there is a problem that the carbon powder adheres or mixes with the held object as foreign matter.

[0009]

Therefore, according to the present invention, a tip member in contact with an object to be clamped is provided with a volume resistivity of 10 ³ to 10 ⁹ Ω.
· Cm and forming of ceramics, and supporting the tip member, and gripping operations that support member ¹⁰¹¹
It is characterized by being made of a material having a volume resistivity of ¹⁶ Ω · cm.

That is, the volume resistivity is 10 ³ to 10 ⁹ Ω · c.
The tip member made of m ceramics induces the action of inducing and removing static electricity, resulting in a volume resistivity of 10 ¹¹ to 10 ^16.
The support member of Ω · cm causes the function of gradually releasing static electricity together with the function of preventing short circuit. As a result, it is possible to prevent an ultra-high voltage discharge caused by the static electricity being removed at once.

[0011] In the present invention, the tip member may have a free carbon content of 0.5% by weight or less and a bending strength of 300M.
It is characterized by being formed of a ceramic of Pa or more.

That is, by setting the free carbon content to 0.5% by weight or less, it is possible to prevent foreign matter from being mixed in the carbon powder and to prevent the tip member from being damaged during normal use if the bending strength is 300 MPa or more. it can.

[0013] In the present invention, as the above-mentioned tip member,
It is characterized by using any of iron oxide-based ceramics, Al ₂ O ₃ —TiC-based ceramics, and conductive zirconia ceramics.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0015] clamping jig shown in Figure 1, to form a pair of tip member 1 of ceramics volume resistivity 10 ³ ~10 ⁹ Ω · cm, the rear end of the tip member 1 volume resistivity 10 ¹¹ -
The support member 2 of 10 ¹⁶ Ω · cm is bonded with an adhesive or the like, and the rear end of the support member 2 is supported by an elastic engagement body 3. The object can be deformed and pinched between the distal end members 1, 1.

In the holding device shown in FIG. 2, a pair of tip members 1 are formed of ceramics having a volume resistivity of 10 ³ to 10 ⁹ Ω · cm.
The support member 2 is fixed to a support member 2 of 0 ¹¹ to 10 ¹⁶ Ω · cm with screws 4, and the support member 2 itself is integrally formed in a V-shaped body. Therefore, when the holding device is gripped by hand, the support member 2 itself is elastically deformed, and the object can be held between the distal end members 1 and 1.

In any of the holding devices, since the tip member 1 is made of ceramics having a low volume resistivity, the supporting member 2 is capable of inducing and removing static electricity and has a high volume resistivity. Thus, a short circuit can be prevented, static electricity can be gradually released, and an ultra-high voltage discharge due to friction with the atmosphere can be prevented.

Here, the volume resistivity of the tip member 1 is set to 10 ³ Ω · cm to 10 ⁹ Ω · cm. If the volume resistivity is less than 10 ³ Ω · cm, the effect of preventing a short circuit becomes poor.
^If it exceeds ⁹ Ω · cm, the effect of removing static electricity will be poor.

The ceramic forming the tip member 1 has a bending strength of 300 MPa or more and a free carbon content of 0.1 MPa.
Those having 1% by weight or less are preferred. This is because the bending strength is 3
If the pressure is less than 00 MPa, the tip member 1 is likely to be damaged during use, and the free carbon content is 0.1% by weight.
This is because if the ratio exceeds the limit, a problem such as the carbon powder adhering to the held object as a foreign substance occurs.

The ceramics constituting such a tip member 1 are preferably iron oxide-based ceramics, Al ₂ O
_3- TiC ceramics or conductive zirconia ceramics are used.

Here, the iron oxide-based ceramic is Fe
_This is a sintered body obtained by adding a stabilizer such as Ca, K, Na, Mg, Zn and Sc to ₂ O ₃ . Further, in order to make the volume specific resistance value and the strength within the ranges described above, for example, 40 to 60% by weight of Fe,
CaF consisting of 8% by weight of Ca and 24-36% by weight of O
e ₂ O ₄ or 30 to 5 in terms of the element ratio in the sintered body.
0 wt% Fe, 18-37 wt% Zn, 24-36
For example, ZnFe ₂ O ₄ composed of O by weight is used. Then, the raw material powder is prepared so as to have the above composition ratio, molded into a predetermined shape by a known method such as press molding or injection molding, and then fired at 1200 to 1500 ° C. in a reducing atmosphere, and then, if necessary. It can be obtained by grinding and polishing.

The Al ₂ O ₃ —TiC ceramic is a sintered body containing alumina (Al ₂ O ₃ ) as a main component, titanium carbide (TiC) and a sintering aid. Further, in order to set the volume resistivity and the strength in the above ranges, the content of TiC may be set to 12 to 30% by weight of the whole, and if necessary, 8 to 2% by weight of the whole.
5 wt% of B ₄ C, may be added to 25 to 45 wt% SiC and the like. Then, the raw material powder is prepared so as to have the above composition ratio, and is molded into a predetermined shape by a known method such as press molding or injection molding.
It can be obtained by firing at 00 ° C., and then grinding and polishing as required.

Further, the conductive zirconia ceramics
This is a sintered body containing zirconia (ZrO ₂ ) as a main component and adding a conductivity-imparting agent and a stabilizer. Specific examples of the conductivity-imparting agent include Ca, K, Na, and M in Fe ₂ O _3.
g, Zn, Sc, etc., an iron oxide-based conductivity-imparting agent, or a titanium carbide-based conductivity imparting agent, such as TiO ₂ or Al ₂ O ₃ , added to TiC. And, in the case of an iron oxide-based conductivity imparting agent, 15 to
The above range of the volume resistivity can be obtained by adding 35% by weight and, in the case of the titanium carbide-based conductivity imparting agent, 10% to 25% by weight based on the whole. Then, the raw material powder is prepared so as to have the above composition ratio, molded into a predetermined shape by a known method such as press molding or injection molding, and then baked at 1100 to 1400 ° C. in an air atmosphere, and then, if necessary. It can be obtained by grinding and polishing.

In addition, since these ceramics do not contain carbon, the content of free carbon can be set to 0.5% by weight or less, and the contamination of carbon powder with foreign substances can be prevented.

Further, silicon carbide ceramics can also be used for applications in which the content of free carbon does not particularly matter. The silicon carbide ceramic has SiC as a main component, and B, C or Al ₂ O ₃ or Y ₂ O as a sintering aid.
_This is a sintered body containing ₃ or the like, and itself is a sintered body having a volume resistivity in the above range.

In the present invention, the expression that the tip member 1 is made of ceramics having a volume resistivity of 10 ³ to 10 ⁹ Ω · cm means that at least the surface of the tip member 1 is made of ceramics in the above range. Therefore, the tip member 1 can be formed by coating the surface of the base with a ceramic within the above range of the volume resistivity.

On the other hand, the supporting member 2 has a volume resistivity of 10
Using the material of ^{11 ~10 16 Ω} · cm, which is 10 ¹¹ Omega
If it is less than cm, the effect of preventing short-circuiting and the effect of gradually releasing static electricity will be poor. On the other hand, it is difficult to make it larger than 10 ¹⁶ Ωcm.

The specific material of the support member 2 is alumina,
Ceramics such as zirconia and silicon nitride and various synthetic resins may be used. In particular, in the case of the structure as shown in FIG. 2, since it is necessary to have elasticity, it is formed of zirconia ceramics or synthetic resin. The zirconia ceramics in this case are mainly composed of zirconia (ZrO ₂ ), Y ₂ O ₃ , CeO, Dy ₂ O ₃ , CaO, Mg
Raw material powder obtained by adding a stabilizer such as O or a well-known sintering aid is formed into a predetermined shape and sintered, and mainly has a tetragonal crystal and an average crystal grain size of 2 μm or less. Partially stabilized zirconia ceramics. Further, various synthetic resins such as vinyl chloride can be used.

Table 1 shows the physical properties of the various materials described above. According to Table 1, as the tip member 1, Al ₂ O ₃ —TiC
-Based ceramics, iron oxide-based ceramics (CaFe ₂ O
₄ , ZnFe ₂ O ₄ ), conductive zirconia ceramics, and silicon carbide ceramics are preferable. In particular, from the viewpoint of the content of free carbon, Al ₂ O ₃ —TiC ceramics;
Iron oxide ceramics (CaFe ₂ O ₄ , ZnFe ₂ O
₄ ), conductive zirconia ceramics are preferred.

Further, it is understood that zirconia ceramics and synthetic resin such as vinyl chloride are suitable for the support member 2.

The bending strength is measured according to JIS-R160.
When the measurement is performed from the actual tip member 1, the measurement is performed by a three-point bending test on a test piece cut into a predetermined shape. At this time, if a test piece having the dimensions specified by JIS cannot be obtained, the bending strength of the test piece specified by JIS may be converted by a known method in consideration of the Weibull coefficient and the effective volume.

Further, the volume specific resistance value is determined according to JIS.
-Measured with a super insulation resistance meter specified in C2141.

[0033]

[Table 1]

Although FIGS. 1 and 2 have described the embodiment of the tweezers which are gripped by hand, the holding device of the present invention is not limited to the tweezers. For example, the clamp of the present invention can be applied to a manipulator or the like that clamps and handles minute elements in an automatic machine or the like. In this case, since the static electricity can be gradually released to prevent the discharge as described above, the adverse effect on the automatic machine side can also be prevented.

Although not shown, a terminal for removing static electricity may be provided in the holding device of the present invention, and this terminal may be used by grounding with a cord or the like.

[0036]

EXAMPLE Here, a clamp as shown in FIG. Assuming that the materials of the tip member 1 and the support member 2 are combinations as shown in Table 2, an additional voltage of 1000 V is applied from the tip member 1 and a test is performed to measure the voltage and the voltage drop time at the support member 2, The degree of removal was evaluated.

As shown in Table 2, the results were as shown in FIG. In No. 6, the effect of removing static electricity was poor because the tip member 1 was a barium titanate-based ceramic having a high volume resistivity. In addition, No. No. 2 has a low volume resistivity of the tip member 1, In No. 4, since the volume resistivity of the support member 2 was low, static electricity was removed at a stretch, and discharge was likely to occur.

On the other hand, the volume specific resistance values of the tip member 1 and the support member 2 are within the range of the present invention. 1,3,3
In the case of No. 5, it was found that static electricity can be gradually released and static electricity can be reliably removed without fear of discharge.

[0039]

[Table 2]

[0040]

As described above in detail, according to the present invention, the tip member in contact with the object to be clamped is provided with a volume resistivity of 10 ³ to 10.
And forming of ceramics ⁹ Omega · cm, and supporting the tip member, and a support member for gripping operation 10 ¹¹ -
Constructed of a material having a volume resistivity of 10 ¹⁶ Ω · cm, it is excellent in heat resistance and corrosion resistance, prevents conduction short circuit, can reliably remove static electricity, and gradually releases static electricity Therefore, the risk of occurrence of discharge can be eliminated.

The tip member has a bending strength of 30%.
When ceramics having a free carbon content of 0.5% by weight or less at 0 MPa or more are used, there is no possibility of breakage at the time of use, and it is possible to prevent foreign matter from being mixed in the carbon powder.

Therefore, according to the present invention, it is possible to provide a high-performance holding tool which has no adverse effect even when holding an electronic component or the like.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a holding device according to the present invention.

FIG. 2 is a perspective view showing an embodiment of a holding device according to the present invention.

[Explanation of symbols]

 1. Tip member 2. Support member 3. Elastic coalescence 4. Screw

Claims (3)

[Claims] A tip member in contact with an object to be held is formed of ceramics having a volume resistivity of 10 ³ Ω · cm to 10 ⁹ Ω · cm, and supporting members for supporting and gripping the tip member are 10 ¹¹ to 10 ^16. A clamp made of a material having a volume resistivity of Ω · cm. 2. The method according to claim 1, wherein the tip member has a free carbon content of 0.5.
The holding tool according to claim 1, wherein the holding tool is made of a ceramic having a flexural strength of not more than 300% by weight. 3. The method according to claim 2, wherein the tip member is an iron oxide ceramic.
Al ₂ O ₃ -TiC based ceramic, pincer of claim 1, wherein the more becomes possible either conductive zirconia ceramics.