JPH01273669A - Electroheating member - Google Patents

Abstract

PURPOSE:To improve the service life of heating members by coating a 1st film having specified specific resistance to the parts of base metals which come into contact with a work and coating a film having a prescribed contact angle with a molten metal of lead or tin, etc., on said film. CONSTITUTION:The 1st coating (SiCN) compsn. which has >=10<-2>OMEGAcm specific resistance is formed on conductive base metals 13 which are the heating members in a vacuum chamber 6 by a plasma CVD method, etc. The 2nd film which consists of a TiN component, etc., and has >=10 contact angle with the molten metal essentially consisting of lead or tin is then formed on the 1st film in succession thereto by using the same device. Lead wires, etc. of ICs are soldered to the heating members 13. Since the 1st film having the high specific resistance ad the 2nd film having poor wettability solder are successively formed on the members 13, the shunting of electric current to a circuit board is decreased and the sticking of the solder is prevented. The service life of the members 13 is, therefore, improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a current-carrying heating member that applies electricity to a conductive substance to generate Joule heat to process a workpiece such as a lead wire. .

(Conventional technology) In recent years, the a+ of factory automation has been remarkable.

An example of this is a device for soldering integrated circuits (ICs) to substrates. In this device, Fe, Mo, W, Ta,
Cu, λ1. Electricity is applied to a heating member made from a base material made of conductive material such as stainless steel, which generates Joule heat.
Soldering is performed by pressing a plurality of lead wires against the board at once using the heating member. Usually, an IC has lead wires protruding from three or four sides, so two or four heating members are installed in parallel or bent in four directions, and electrically connected in series. They may be connected in parallel, but in this case, the current capacity required for the entire device increases.

When soldering is performed by directly contacting the heating member made of a conductive material with the lead wires of the IC, the wiring of the board is connected in series and the force q (at the point where the heating members are connected) is increased from the heating member to the board. There was a problem in which the current shunted to the wiring, causing the wiring on the board to break. Therefore, the present inventor previously proposed that the surface of a base material made of a conductive substance be coated with an insulating film to prevent the current from being shunted from the heating member to the wiring on the board.

(Problems to be Solved by the Invention) However, such a heating member has a drawback in that solder tends to adhere to the heating member depending on the material of the insulating coating and the condition of the surface.

In the present invention, at least a portion of the heating member in contact with the lead wire of the IC is coated with an insulating first coating, and further the first coating is coated with an insulating first coating.
The solder layer has poor wettability with solder on the surface of the coating, and by covering it with a second coating made of a trap material, it is possible to prevent solder from adhering to the heating member and to perform good processing. purpose.

[Structure of the invention]

(Means for Solving the Problems) The electrical heating member of the present invention has a surface of a base material made of an electrically conductive material that has a specific resistance of 1.
A second coating made of a material having a contact angle of 10 degrees or more with a molten metal containing at least one of lead or tin as a main component is coated on the surface of the first coating. It is characterized by being coated with a film of. In this case, the contact angle refers to the angle formed at the contact line when the molten metal is in contact with the solid material. Therefore, the larger the contact angle of the material, the worse the wettability with the molten metal, indicating that the molten metal is less likely to adhere to the material.

More specifically, the material of the second coating is Ti.
, W, Ag, Au, Cr, C, O, and N. The reason is as described below. First, the second coating must be made of a material that does not peel off from the base material during heat cycles from about 150'O to about 300°C. In addition, in automated soldering equipment, the heating member heats up at intervals of several seconds.
Since the temperature is lowered, the material of the coating must have high thermal conductivity. Therefore, the thickness of the coating is 41 μm.
If it exceeds 1wm-', the thermal conductivity must be -1 to 1wm-' or more. All materials containing the above-mentioned elements have high thermal conductivity in degrees Celsius.

Furthermore, since the heating material has a potential difference of about 1 to 1 Ov with respect to the ground potential, the second coating needs to have a thickness that does not cause dielectric breakdown with respect to this voltage. Therefore, the thickness of the second coating is 500A or more, preferably 100OA.
The above is necessary, and considering abrasion resistance, a thickness of about 2 μm is required.

Considering thermal conductivity, it is not preferable to make the thickness 5 μm or more. The first of these. Sputtering is a method for coating the surface of the base material with the second coating.

Ion grating, vacuum deposition, glazma CVD.

ECR7' Raz-rcVD, thermal CVD, optical CVD
and so on. Among these, plasma
vD method and ECR Glazma CVD method are suitable.

(Function) A first insulating film is coated on at least a portion of the heating member that is in contact with the lead wire of the IC, and a second film having wettability with solder is further coated on the surface of this insulating film. This eliminates the problem of solder adhering to the heating member.

(Example) In the heating member of this example, a conductive material is processed as shown in FIG. It is coated with a second coating having poor properties.

Automated soldering is performed by installing these heating members in a surrounding area as shown in Figure 2, and connecting them electrically in series to a 50Hz variable current power source. .

The processing step is energization as shown below. After the IC is placed on the board and automatically transported to ℃, the heating member is lowered to ℃.
At the same time, while pressing the lead wire C with a pressure of about 2 kg/mouth 2, a t current of about 50 OA was supplied to the heating member, and the
Heat to 0″C.

After the solder is melted and the lead wires and the circuit on the board are connected,
When the electricity is turned off and the solder hardens, the heating member is raised and this process is completed.

Below, an example will be described in which a heating member of the present invention was manufactured by coating the surface of a base material made of a conductive substance with the above-mentioned first coating and second coating.

Example 1゜In this example, the surface of the base material was coated with a first insulating film containing the components shown in Table 1 and a second film containing the components shown in Table 2 using the plasma CVD method. . FIG. 3 is a schematic diagram of a parallel plate type capacitively coupled plasma CVD apparatus. Inside the vacuum chamber 6, a flat ground electrode 7 and a high frequency electrode 8 are installed facing each other. Further, the entire X chamber 6 is provided with a gas inlet 12. A heater 9 is attached to the ground electrode 7, and the high frequency power 8 is connected to the high frequency [pole 11] via a matching box 10.

Using this apparatus, first an electrically conductive heating member was coated with a first insulating film. The four-electric heating member 1 was placed on the ground electrode 7, and the inside of the chamber 6 was evacuated to about 10 Torr using an X-nitrogen bong (not shown). Next, the heating member 13 is heated from 150°C to about 450°C by the heater 9 attached to the ground electrode 7, and the SiH4 gas inlet 12 is heated.
N2. A raw material gas such as CH4 is supplied into the chamber 6, and the degree of vacuum in the chamber 6 is maintained at 0.05 to 1. QTorr
It was vented to keep it cool. When power is applied to the high-frequency electrode 8, a glow discharge occurs between the electrodes, the raw material gas becomes a glaze, and an insulating thin film is coated on the heating member 13.The composition of the coating, the raw material gas, and the film forming conditions are shown in Table 1. As shown.

For example, when forming a film having a composition of 5iCN, 5iHa 100 S CCM is used as the source gas.

N, 500SCCM and CH, 400SCCM were introduced through the gas inlet 12, and the reaction pressure in the chamber 6 was set to 1.0.
Hold Torr K, high frequency i! Film formation was performed by applying a voltage of 500 W to the c-pole 8. In this case, the film formation time is 4
A film with a thickness of 3.0 μm was formed in 0 minutes.

Below, the components of the insulating film formed similarly for films of other components, the raw material gas and its flow rate, the reaction pressure in the chamber,
Power applied to the high frequency electrode 8.

The film formation time and film thickness are too small as shown in Table 1.

Thereafter, in the margin, the second coating was coated on the surface of the first coating in the same manner as the first coating. The components of the formed film, the raw material gas and its flow rate, the reaction pressure in the chamber 6, and the electric power applied to the high frequency electrode 8.

The film formation time and film thickness are as shown in Table 2. For example, T
When removing the film of iN component, use TiC summer as raw material gas, 208CCM of N2, 30080CM of N2, and N2.
2 with 2008 CCM from gas inlet port 12,
The reaction pressure in the chamber 6 was maintained at 1.0 Torr,
Film formation was performed by applying a voltage of 500 W to the high frequency electrode 8. In this case, a film with a thickness of 1.0 μm was formed in 30 minutes. Below, the components of films formed in the same way for films of other components are shown.

Raw material gas, its flow rate, and reaction pressure in the chamber.

The power applied to the high frequency electrode 8, the film formation time, and the film thickness are determined by the second
The amount is too low as shown in the table.

According to the following margin plasma CVD method, the heating member is heated to 150°C to 4°C.
Since it can be processed at a relatively low temperature of 50°0, it is possible to obtain a good coating with strong adhesion between the base material and the first coating, and between the first coating and the second coating, without impairing the properties of the heating member. It will be done.

Example 2 In this example, a first film containing the components shown in Table 3 and a second film containing the components shown in Table N4 were formed by sputtering. The sputtering apparatus used is as shown in FIG. Inside the vacuum chamber 6, a flat ground electrode 7 and a high frequency electrode 8 are arranged facing each other, and a heater 9 is attached to the flat ground electrode 7. The high frequency electrode 8 is connected to a high frequency electrode 11 via a matching box 10. A gas inlet 12 is provided in the side wall of the vacuum chamber 6 . In this way, the sputtering apparatus is similar to the plasma CVD apparatus described above, but the only difference is that the high-frequency electrode 8 is provided with a solid raw material as the target 14. In order to form the first insulating film using this apparatus, first, a solid raw material was placed as the target 14, and 9Ar gas and optionally a reaction gas were simultaneously introduced through the gas inlet 12. After these gases were turned into a glazoma and human ions ejected the substance of the target 14 in atomic or molecular form, an insulating film was formed on the surface of the heating member 130 while reacting in the plasma of the reaction gas. Table 3 lists the components, raw materials, film forming conditions, etc. of the film formed. For example, to form a film made of amorphous silicon, set monocrystalline or polycrystalline silicon as a target, introduce pAr gas IO8CCM, H, and gas 100SCCM through the gas inlet 12 to lower the chamber internal pressure to lXl0Tart. The film was formed by keeping the voltage at 500 W and applying a voltage of 500 W to the high frequency electrode 8.

In this case, an amorphous silicon film having a thickness of 3.0 μm was formed in a film forming time of 60 minutes. In addition, Ar gas, H! Gas and simultaneous KB, H6 gas ISCCM or P
Hs gas ISCCM may be introduced. Regarding films of other components, the target solid, raw material gas and its flow rate, reaction pressure in the chamber 6, electric power applied to the high frequency electrode 8, film formation time, and film thickness are shown in Table 3 below. Described.

Margin below Next, a second coating was formed on the surface of the first coating by a similar sputtering method. Table 4 lists the components, raw materials, film forming conditions, etc. of the film formed. for example,
To form a film consisting of a TiN component, a metal Ti is set as a target, 10800 M of pkr gas and 50 SCCM of N2 gas are introduced through the gas inlet 12, and the pressure inside the chamber is maintained at 1X10 Torr. Film formation was performed under a voltage of 800W. In this case, a TiN film having a thickness of 3.0 μm was formed in a film forming time of 60 minutes. Hereinafter, regarding coatings of other components, the target solid, Ti material gas and its flow rate, chamber 6
The reaction pressure within, the electric power applied to the high frequency electrode 8, the film forming time, and the film thickness of the film are listed in Table 4.

The blank space sputtering method is easy to handle because a solid material can be used as a raw material, and there is no need to change the shape of the device depending on the shape of the heating member, so it can be said to be a versatile method.

Example 3 In this example, the first insulating film and the second film were formed by the EC-glazma CVD method.

The apparatus used in this method is as shown in FIG.

A gas inlet 12 is provided in the side wall of the film forming chamber 15 . Further, a plasma forming chamber 16 is disposed in the upper blade of the film forming chamber 15, and is communicated with the film forming chamber 16 through a plasma inlet 18 provided in a cutting plate 17 at a temperature of .degree. A quartz plate 19 is arranged on the earthen wall of the plasma formation chamber 16.
A microwave waveguide 20 is disposed above. Further, a gas inlet 21 is provided on the upper wall of the plasma forming base 16, and an electromagnet 22 is provided around the plasma forming chamber 16.

To coat the heating member with an insulating coating using a heating device,
The heating member 13 was installed at the bottom of the film forming chamber 15, and the following undersized film formation was performed. The inside of the film forming chamber 15 was evacuated using a vacuum bonder and maintained at a degree of vacuum of 1×10 −3 to 1×10 −3 . The inlet pipe 12 supplies the raw material gas to the film forming chamber 15, and the inlet pipe 21 supplies the reaction gas (N*, Ox, CH4, etc.) to the siglasma formation chamber.
Alternatively, gases (Ar, He, H@2) that do not react themselves but supply energy to others are introduced. When a 2.4 s GHz microwave is introduced into the plasma formation chamber 16, an electric field E is generated by the microwave. In addition, a current is passed through the ff1 stone 22 to form a magnetic field B of 875 Gauss within the plasma formation chamber 16. The electrons in the plasma formation chamber 16 resonate and are excited, and the resonance of these electrons supplies energy to the N t or Ar gas introduced from the introduction tube 21 to form plasma of these gases. . This plasma is drawn out to the film forming chamber 15 through the plasma outlet tube 18 as the magnetic field diverges. Introducing pipe 12 into film forming chamber 15]
The components of the introduced raw material gas were formed into a film on the surface of the flat plate-shaped force-Ω heating member 13 in the film-forming chamber 15 . The raw material gas, film forming conditions, etc. for each film are listed in Table 5. For example, 5iC
When forming a film containing N component, SiH41 is used as a raw material.
0SCCM was introduced through the gas inlet trap, and N and 50SCCA4 were introduced as reaction gases through the gas inlet. The pressure in the chamber was kept at 3×10 To(r) and the microwave power was 500 W. In this case, the film formation time was 40
Film thickness in minutes 3. A coating of Om was obtained. Below, for coatings of other components, the raw material gas and its flow rate,
Reaction pressure in the film forming chamber 15, microwave power, film forming time,
The film thickness is listed.

Thereafter, a second coating was formed on the surface of the first coating using the same EC plasma CVD method. The raw material gas, film forming conditions, etc. for each film are listed in Table 6. For example, T1C
When forming a film containing N component, TiCl41 is used as a raw material.
08CCM was introduced through the gas inlet, and as a reaction gas,
CH, 208CCM and N snow 508CCM and H2 2
00SCCM was introduced through the gas inlet. Film forming chamber 1
The pressure inside the chamber was kept at 3×10 Torr and the microwave power was set at 100 OW. In this case, in Table 5, the raw material gas and its flow rate, the reaction pressure in the film-forming chamber 35, the microwave power, the film-forming time, and the film thickness are also listed for the film that took 60 minutes to form.

As described above, according to the KECR and plasma CVD methods, processing can be performed without heating the heating member, and a film can be formed that has uniform components and adheres to the member.

If KAr ion bombardment treatment is performed before film formation as shown in Examples 1 to 3 above, the degree of adhesion between the film and the base material can be increased. Plasma CVD is used to perform this treatment.
In the case of the plasma CVD method, the glazema can be formed by flowing KAr without supplying the raw material gas for the coating, and in the case of the sputtering method, it is enough to apply electric power to the base material instead of the target. .

Furthermore, in order to increase the degree of adhesion between the coating and the base material, it is preferable to form a region containing more nitrogen, carbon, oxygen, etc. than the base material at the interface between the coating and the base material. For this purpose, ion nitriding,
A base material that has been carburized, etc. is coated with an insulating film, and during the ion bombardment, KAr gas is mixed with N, 0.
, CH, etc. may be mixed. Also, N,,02. C
Ion bombardment of a gas such as H4 may also be performed.

In this way, by coating the surface of the base material made of a conductive material with the first insulating film, there will be no shunting of current from the member to the circuit of the board, and good processing will be achieved. can be administered. In addition, by coating the surface of this insulating film with a second film, we have created a heating member that is difficult to adhere to with solder, has excellent wear resistance and oxidation resistance, and can withstand tens of thousands of uses. can be provided.

〔effect〕

As detailed above, according to the heating member of the present invention coated with a film made of a material having poor wettability with solder, the solder adheres to the heating member and the heating member can be processed satisfactorily.

[Brief explanation of the drawing]

The drawings all relate to the embodiments. Figure 1 is a perspective view of one heating member, Figure 2 is a schematic diagram showing how four heating members are connected in series, and Figures 3 to 3. Fig. 5 is a schematic diagram of an apparatus for manufacturing a heating member, Fig. 3 is a schematic diagram of a plasma CVD apparatus, Fig. 4 is a schematic diagram of a sputtering apparatus, and Fig. 5 is a schematic diagram of an EC/glazma CVD 1 installation. It is a schematic diagram. Agent Patent Attorney Nori Chika Shigeaki Yamashita - Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In a member that heats a workpiece by applying electricity to a base material made of a conductive substance and processes a workpiece, at least a portion of the base material in contact with the workpiece has a first coating having a specific resistance of 10^-^2 Ωcm or more. The surface of the first coating is further coated with a second coating having a contact angle of 10 degrees or more with a molten metal containing at least one of lead or tin as a main component. An energized heating member.