JPH06166568A - Graphite jig - Google Patents

Abstract

PURPOSE:To obtain the subject graphite jig to be used in the bonding of electronic part, exhibiting excellent abrasion resistance in the friction with electronic part and free from contamination with graphite powder by coating a graphite material having a specific thermal expansion coefficient with a pyrolytic carbon layer having a specific thickness. CONSTITUTION:A graphite jig to be used in the bonding, glass-sealing, positioning and soldering of electronic part is produced by coating the surface of an isotropic graphite material having a thermal expansion coefficient of 1.5X10<-6> to 7.0X10<-6> deg.C<-1> with a pyrolytic carbon layer to a thickness of 0.5-25.0mum. The coating film of the pyrolytic carbon is free from pore and has dense texture and high hardness and abrasion resistance. Since the pyrolytic carbon coating film is formed on the graphite surface while sealing the processing dust existing in the pore on the surface of the graphite material, the pore is embedded in high efficiency and, accordingly, the contact abrasion resistance of the surface of the graphite material can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphite jig, and more particularly to a graphite jig suitable for manufacturing electronic components such as transistor / diode bonding, glass sealing, ceramic package positioning, lead frame brazing and the like. Regarding the ingredients.

[0002]

2. Description of the Related Art Conventionally, this type of graphite jig is an electronic component that requires a fine and precise shape due to its excellent thermal properties (high thermal conductivity, low thermal expansion coefficient) and easy workability. Joining the
It has been widely used as a jig for glass sealing, positioning, and brazing.

[0003]

However, while the graphite jig has the advantage of easy workability, it is fragile, and therefore, when the electronic component is mounted on the graphite jig, the graphite jig at the end thereof is disposed. It has a drawback that it is easily worn due to contact with the tool and contact with the hole wall when inserting the lead into the alignment hole. Therefore, there is a problem that the graphite jig has a short life and the graphite powder generated by abrasion contaminates the electronic component itself and the working environment. In addition, the graphite powder that has entered the pores of the graphite material has a problem that the graphite powder jumps outside and contaminates the surroundings during the manufacturing of the electronic component. Further, this graphite powder has a problem that it is not easy to remove it and a complicated cleaning step for removal is required. The present invention is intended to solve the above problems, and an object of the present invention is to provide a graphite jig that is excellent in abrasion resistance against friction with electronic components and that does not contaminate a work environment or the like with graphite powder.

[0004]

In order to achieve the above object, a structural feature of the present invention is a graphite jig used for joining electronic parts, glass sealing, positioning, and brazing,
Isotropic and has a coefficient of thermal expansion of 1.5 × 10 ^{−6 to} 7.0 × 10 ⁻⁶
° C. 0.5 to pyrolytic carbon on the surface of the graphite material is in the range of ^-1
It is to be coated to a thickness of 25.0 μm and to confine the processed powder in the pores of the graphite material.

Here, the graphite material used must be isotropic. In the case of anisotropic graphite material, since the anisotropic ratio of thermal expansion coefficient is 1.30 or more, the mismatch of thermal expansion is extremely large between the pyrolytic carbon coating and the graphite material, especially at the corners. And cracks and peeling occur. In the case of an isotropic graphite material, the film thickness of the pyrolytic carbon coating is 0.
If it is in the range of 5 to 25.0 μm, it is desirable that the thermal expansion coefficient of the graphite material is in the range of 1.5 × 10 ^{−6 to} 7.0 × 10 ⁻⁶ ° C. ⁻¹ . In particular, the number of pins in a package is increasing and the accuracy of finishing of the package is being improved. In manufacturing such a high value-added product, the thermal expansion coefficient is 2. to enhance the robustness of the pyrolytic carbon coating. 0 × 10 ⁻⁶ to 4.
It is preferable to use a graphite material of 0 × 10 ⁻⁶ ° C. ⁻¹ . In addition, the bulk specific gravity of the graphite material improves the compatibility with the pyrolytic carbon coating and enhances the fastness of the coating to 1.7.
It is preferably 3 or more.

As a method for forming a pyrolytic carbon coating, PV is used.
The D method or the CVD method is used. The CVD method uses methane,
A hydrocarbon gas such as propane and a carrier gas such as hydrogen are reacted on the surface of a graphite material to form pyrolytic carbon. The treatment temperature is 1000 to 3200 ° C., and particularly from the viewpoint of film quality and economical efficiency. 1100 to 1250 ° C is preferable. The film thickness can be adjusted by the hydrocarbon gas concentration, the processing temperature, and the processing time, but if it is 0.5 μm or less, pinholes are generated, which is not preferable in terms of airtightness of the film, and 25.0 μm or more. If so, thermal stress exceeding the limit acts on the film during heating and the probability of cracking increases.

[0007]

In the present invention constructed as described above, the entire surface of the graphite jig or a necessary portion thereof is coated with pyrolytic carbon having the above thermal expansion coefficient in a thickness range of 0.5 to 25 μm. . This pyrolytic carbon coating has no pores,
Dense, hard and abrasion resistant. Further, since this pyrolytic carbon coating is laminated on the surface of the graphite material while confining the processed powder in the pores on the surface of the graphite material, the pore can be efficiently filled and the graphite material can be filled by filling the pores. The contact wear resistance of the surface is improved. That is, when the electronic component is positioned and arranged on the graphite jig, abrasion of the pyrolytic carbon coating due to contact of the end of the electronic component with the graphite jig or contact with the positioning hole of the lead is suppressed, Graphite powder does not scatter from the graphite material. Further, the processed powder of graphite trapped in the pores of the graphite material does not scatter to the outside of the graphite material.

[0008]

As a result, the durability of the graphite jig is enhanced, and the graphite particles are trapped in the graphite jig. Environmental pollution is prevented.

[0009]

EXAMPLES Examples of the present invention will be described below. (1) Preparation of sample Isotropic, bulk specific gravity of 1.8 and thermal expansion coefficient of 2.0 × 10 ^-6
A graphite jig having a length of 120 mm, a width of 190 mm, and a thickness of 10 mm was manufactured by processing a graphite jig of up to 4.0 × 10 ^-6 ° C ^-1 . This graphite jig is CV
It is provided in a D furnace, heated to 1400 ° C., hydrogen gas is used as a carrier gas, and methane is supplied as a hydrocarbon gas into the furnace to form a pyrolytic carbon coating having a thickness of 0.5 μm and 10 μm on the surface of a graphite jig. The sample was formed to be Sample 1 and Sample 2. In addition,
For comparison, a graphite jig provided with a pyrolytic carbon coating having a film thickness of 0.3 μm was manufactured under the same conditions as above, but the entire surface could not be covered with the pyrolytic carbon coating, and pinholes were generated. Further, with respect to the graphite jig provided with the pyrolytic carbon coating having a film thickness of 30 μm, peeling of the pyrolytic carbon coating occurred.

(2) Test Result 1 In this graphite jig sample 1, after inserting the lead of the electronic component into the alignment hole and positioning the ring, the temperature inside the furnace 92
The glass was sealed by holding it in a furnace at 5 ° C. in a nitrogen atmosphere for 30 minutes. As a result, even if the glass sealing work was repeated 125 times or more, no stain due to graphite powder was found on the sealed glass. That is, only 0.
Even with the 5 μm pyrolytic carbon coating, the wear resistance of the graphite jig is maintained, the graphite material is not exposed, and therefore the graphite powder trapped in the pores of the graphite material does not fly out. It was revealed that the graphite powder did not scatter due to the friction between the graphite material and the electronic component. The graphite jig sample 2 was glass-sealed under the same conditions as above. As a result, 30 such glass sealing work is required.
Even after repeating 0 times or more, no stain due to graphite powder was found on the sealed glass. That is, it has been clarified that the wear resistance of the graphite jig is further enhanced and the graphite material is not exposed by coating the pyrolytic carbon film with a thickness of 10 μm. For comparison, the lead and ring of the electronic component were positioned as described above for the graphite jig processed with the isotropic graphite material not coated with the pyrolytic carbon coating, and the furnace temperature was 925 ° C. and the furnace was in a nitrogen atmosphere. The glass was sealed for 30 minutes. As a result, the glass was found to be contaminated with graphite powder after one sealing operation.

(3) Test result 2 The lead frame and the ceramic substrate of the ceramic package for semiconductor were positioned on this graphite jig sample 1 and brazing was performed. As a result, even when the brazing operation was repeated 125 times or more, neither adhesion of the brazing portion to the graphite jig nor reaction of the brazing portion with graphite powder was observed. That is, the wear resistance of the graphite jig is maintained even by coating the pyrolytic carbon film of only 0.5 μm,
It was revealed that the graphite material was not exposed, that is, the graphite powder trapped in the pores of the graphite material did not fly out, and the graphite powder did not scatter due to the friction between the graphite material and the electronic component. The graphite jig sample 2 was brazed on the lead frame of the ceramic package for semiconductor and the ceramic substrate under the same conditions as above. As a result, even when such brazing work was repeated 300 times or more, neither adhesion of the brazing part to the graphite jig nor reaction of the brazing part with graphite powder was observed. That is, it has been clarified that the wear resistance of the graphite jig is further enhanced and the graphite material is not exposed by coating the pyrolytic carbon film with a thickness of 10 μm. As a comparison, the lead frame and the ceramic substrate of the ceramic package for a semiconductor were positioned and brazed as described above with respect to a graphite jig processed with an isotropic graphite material not coated with a pyrolytic carbon film. As a result, it was confirmed that the brazing part was adhered to the graphite jig and the brazing part was reacted with the graphite powder by one sealing operation.

As described above, the graphite jig according to the above embodiment is formed by coating the graphite material with pyrolytic carbon,
By confining the processed graphite powder in the pores of the graphite material, the abrasion resistance against contact with electronic parts etc. is significantly improved, the durability is increased and the electronic parts themselves and the work environment are prevented from being contaminated by the graphite powder. To be done.

Claims (1)

[Claims] 1. A graphite jig used for joining electronic parts, sealing glass, positioning, and brazing, which is isotropic and has a thermal expansion coefficient of 1.5 × 10 ^{−6 to} 7.0 × 10 ^−6.
° C. 0.5 to pyrolytic carbon on the surface of the graphite material is in the range of ^-1
A graphite jig having a thickness of 25.0 μm and confining the processed powder in a pore of a graphite material.