JPH026053A - Electric heating member - Google Patents

Abstract

PURPOSE:To prevent the shunting of a current and the deposition of solder on the heating member by covering the contact part of the heating member with a material to be worked with a coating film having a specified contact angle to the melt of a metal consisting essentially of one out of lead and tin. CONSTITUTION:At least the contact part of the electric heating member with a lead wire on the surface of a base material consisting of a conductive material is covered with a coating film consisting of a material having resistivity higher than that of the base material at 10<-2>OMEGAcm and >=10 deg. contact angle to the melt of a metal consisting essentially of one out of lead and tin. Since at least the contact part of the heating member with the lead wire of an IC is thus covered with the insulating coating film having poor solder wettability and on which solder is hardly deposited, the breaking of wiring due to the shunting of a current from the heating member to the wiring of the substrate and the deposition of solder on the heating member are prevented.

Description

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

(Prior Art) In recent years, there has been remarkable progress in factory automation. An example of this is a device that solders four integrated circuits (ICs) onto four boards. In this device, Fe, Mo, 'W, T
By applying electricity to a heating member made of a base material made of a conductive material such as a, Cu, AI, or stainless steel and generating Joule heat, the heating member presses multiple lead wires against the board at once. Performing soldering. Usually I
C has lead wires coming out on all sides, so two or four heating members are installed in parallel or surrounding them on all sides, and are electrically connected in series.

They may be connected in parallel, but in this case the number of currents required for the entire device increases.

When a heating member made of a conductive material is soldered by directly contacting the lead wires of an IC, current flows from the heating member to the wiring on the board at the point where the wiring on the board connects the heating members connected in series. There was a problem in which the current shunted and the wiring on the board broke. Further, there was also a problem that solder easily adhered to the heating member.

(Problems to be Solved by the Invention) As described above, it is important to avoid direct contact of the heating member made of a conductive material with the lead wires of the IC, and to connect the heating member to the circuit board wiring by soldering (such as soldering). A current shunt occurs,
There were problems such as wires breaking and solder adhering to the heating member.

In the present invention, at least the portion of the heating member in contact with the IC lead wires is coated with a coating made of a material that is insulative and has poor wettability with solder, making it difficult for solder to adhere to the wiring from the heating member to the wiring on the board. The purpose is to prevent wire breakage and solder adhesion to heating components due to current shunting, and to ensure good processing.

[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, at least a portion in contact with a lead wire, which has a specific resistance of 10- 2 Ωcm or more, and the contact angle with a molten metal containing lead or tin as the main component is 1.
It is characterized by being coated with a film made of a material with a temperature of 0 degrees or higher. 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 better the metal melt! It has poor wettability with the snout and does not show that molten metal is difficult to adhere to.

More specifically, as the material for the coating, a material containing at least one element selected from C90 and N is used. The reason is as described below.

First, the coating must be made of a material that does not peel off from the base material during a P-1 cycle at temperatures from about 150°C to about 300°C. Furthermore, in automated soldering equipment, the temperature of the heating member is raised and lowered in cycles of several seconds, so the material of the coating must have high thermal conductivity. Therefore, when the thickness of the coating exceeds 1 μm, the heat conductivity S must be greater than iWm-tk-. 1) All materials containing the above-mentioned elements have high thermal conductivity.

Further, since the heating material 11 has a potential difference of about 1 to 10 V with respect to the ground potential, the coating needs to have a thickness that does not cause an insulating coating to occur with respect to this voltage. Therefore, the thickness of the second coating needs to be 500A or more, preferably 100OA or more, and when wear resistance is also considered, it needs to be about 2 μm. Consider thermal conductivity! Therefore, it is not preferable to make the thickness 5 μm or more. Methods for coating the surface of the moon with the film include sputtering and ion blasting.

(゛4 blank evaporation, 77?CVD, ECR75, 2”VC
There are VD, thermal CVD, optical CVD, etc. Among these, the plasma CVD method and the ECR Blaze CVD method are suitable, considering that the adhesion of the film is good, the film can be α-beated at a relatively low temperature without damaging its properties, and the electrical properties of the film are difficult to control. Particularly appropriate.

(Function) By coating at least the portion of the heating mu in contact with the lead wire of the IC with the second film which is insulating and has poor wettability with solder, the problem of solder adhering to the heating member is eliminated.

(Example) The heating member of the present invention is formed by processing a conductive material as shown in FIG. 1, and covering the surface with a film that is insulating and has poor wettability with solder.

Automated soldering is performed by installing the heating members on all sides as shown in Figure 2, and connecting them electrically in series to a 501-1z AC power source. Ru.

The processing steps are as shown below. After the IC on the tL base plate is placed and automatically transported, the heating member comes down and presses the IC lead wire with a pressure of approximately 2 kg/cm2, and at the same time, a current of approximately 500△ is applied to the heating member. supply,
Heat to about 300℃.

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 turned on 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 insulating film and poor wettability with solder.

Example 1 In this example, a film containing the components shown in Table 1 was coated on the surface of a base material by plasma CVD.

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 vacuum chamber 6 is provided with a gas introduction port 12 .

A heater 9 is attached to the ground electrode 7, and a high frequency power source 8 is connected to a high frequency electrode 11 via a matching box 10.

Using this apparatus, the conductive heating member was first coated with the film. The conductive heating member 13 is placed on the ground electrode 7, as shown in FIG.
The inside of the chamber 6 is heated to 1O-6T by a vacuum pump that does not
It was exhausted to about orr. Next, the heating member 13 is heated from 150'C to 459°C by the heater 9 attached to the ground electrode 7.
Heat to a moderate level and connect gas inlet 12 with H4, N2,
A raw v1 gas such as Cl-1,s is supplied into the chamber 6, and the degree of vacuum in the chamber 6 is set to 0.05 to 1.0To.
It was evacuated to keep it at rr. When power is applied to the high-frequency electrode 8, a glow discharge occurs between the electrodes, the raw material gas becomes plasma, and the insulating 77Q film is coated on the heating member 13.The components, raw material gas, and film forming conditions of the coating are shown in Table 1. As shown. For example, JJ deposits mvA of Si CN composition.
For J, the source gas is TSi t-14100SCC.
M, N 2500 S CG M, CH, +
4003 CCM was introduced through the gas inlet 12, the reaction pressure in the chamber 6 was maintained at 1.0 Torr, and a voltage of 500 W was applied to the high frequency electrode 8 to form a film.

In this case, a film with a thickness of 3.0 μn1 was formed in a film forming time of 40 minutes.

Below, the components of the insulating wl film formed in the same way for films of other components, the raw material gas and its outflow, the reaction pressure in the chamber, and the power applied to the high-frequency electrode 8 will be described.

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

(Left below) When using the plasma CVD method, the heating member can be processed at a relatively low temperature of 150°C to 450°C, which results in a strong bond with the base material without impairing the properties of the heating member. na i1
! The membrane is 1!7.

- Actual Flow Example 2 In this example, a film containing the components shown in Table 2 was formed by a sputtering method. The sputtering equipment used is the fourth
As shown in the figure. A flat ground type ViA 7 and a high frequency ml&8 are installed facing each other in the vacuum chamber 6, and a heater 9 is attached to the flat grounded electric bed 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 device, first, a solid raw material is placed as the target 14, and the gas inlet 12 is
Ar gas and, if necessary, reaction gas were simultaneously introduced.

These gases turn into plasma and Δr ions reach target 1.
After the substance No. 4 was knocked out in the form of atoms or molecules, an insulating film was formed on the surface of the heating member 13 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, in order to form a film made of amorphous silicon, single crystal or polycrystalline silicon is set as a target, and Ar jj gas 0SCCM, 1-12 is injected from the gas inlet 12.
1003 CCM was introduced, the pressure inside the chamber was maintained at 1×10 −3 Torr, and a voltage of 500 W was applied to the high frequency electrode 8 to form a film.

In this case, 3. An amorphous silicon film having a thickness of Oflm was formed. In addition, A as a raw material gas
B2 H6 gas ISCCM or 18 CCM of Pl-13 gas may be introduced simultaneously with r gas and H2 gas. Similarly, for coatings of other components, the target solid,
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.

Described.

The film formation time and film thickness are shown in Table 3 (blank below). Sputtering is easy to handle because it can use solids as raw materials, and there is no need to change the shape of the equipment depending on the shape of the heating member, making it a versatile method. It can be said to be a method.

Example 3 In this example, a film was formed on the surface of the base material by the ECR plasma CVD method. The equipment used in this method is
As shown in the figure. A gas inlet 12 is provided in the side wall of the film forming chamber 15 .

Further, a plasma forming chamber 16 is arranged above the film forming chamber 15, and communicates with this film forming chamber 16 through a plasma inlet 18 provided in a partition plate 17. A quartz plate 19 is disposed on the earthen wall of the plasma formation chamber 16, and a microphone [1 wave power wave tube 20] is disposed above the quartz plate 19. Further, a gas inlet 21 is provided in the earthen wall of the plasma forming chamber 16, and an electromagnet 22 is provided around the plasma forming chamber 16.

To coat the heating member with an insulating film using this device,
The heating member 13 was installed at the bottom of the film forming chamber 15, and film formation was performed as follows. The inside of the film forming chamber 15 was evacuated by a vacuum pump and maintained at a degree of vacuum of 1.times.10@-5 to 1.times.10@-3.

Source gas is introduced into the film forming chamber 15 through the introduction pipe 12, and reaction gas (N2.02, CH4, etc.) is introduced into the plasma formation chamber through the introduction pipe 21.
Alternatively, gases (Ar, He, 1-12) that do not react themselves but supply energy to others can be F'
L was introduced.

When a 20J microwave waveguide and a 2.45 GHz microwave are introduced into the plasma formation chamber 16, an electric current QE is generated in the microwave. In addition, a current of 875 Gauss In, l is applied to the electromagnet 22 in the plasma formation chamber 16.
Form J2 B. Electrons within the plasma formation chamber 16 resonate and are excited. When the electrons are introduced from the inlet pipe 21 into resonance, their energy is supplied to the N2 or Ar gas, forming a plasma of these gases. Due to the divergence of the limited field, this plasma
8 into the film forming chamber 15. The components of the raw material gas introduced into the film forming chamber 15 through the introduction pipe 12 were deposited on the surface of the flat, plate-shaped heating member 13 in the film forming chamber 15 . The raw material gas and film forming conditions S for each film are listed in Table 5. For example, when forming a film with sr@N component, S
tt1410SCCM was introduced through the gas inlet, and N2503CCM was introduced as a reaction gas through the gas inlet. The pressure inside the chamber is 3X 10”” Tor
The microwave power was set at 500 W. in this case,
The film thickness was 3.5 minutes after the film formation time was 40 minutes. A coating of Om was obtained. Hereinafter, for coatings of other components, the raw material gas and its flow rate, the reaction pressure in the film forming chamber 15, the microwave power,
The film formation time and film thickness were set to 2.

(Left below) As described above, according to the ECII plasma CVD method, the process can be performed without heating the heating member, and a film having uniform components and adhering to the member can be formed.

If the Δr ion bombardment treatment is performed before the film formation shown in Examples 1 to 3 above, the degree of adhesion between the film and the base material can be increased. To perform this treatment, in the case of the plasma CVD method and the ECR plasma CVO method, plasma is formed by flowing 8r without supplying the raw material gas that forms the film, and in the case of the spackling method, the target Instead, the power should be applied to Dan H instead.

Furthermore, in order to increase the degree of adhesion between the coating and the base material, it is preferable to form a region containing nitrogen, carbon, and oxygen in a larger amount than the base material at the interface between the coating and the base material. For this purpose, ion nitriding,
The base material that has been carburized is coated with an insulating film, or N2.02 is added to the Ar gas during the ion bombardment.
, CH4, etc. may be mixed. Also, N2.02, C
Ion bombardment with a gas such as l-14 may also be performed.

In this way, by coating the surface of the base material made of a conductive substance with a film made of a material that is insulating and has poor wettability with solder, there is no shunting of current from the heating member to the circuit on the board. It is possible to provide a heating member that can be subjected to various processing, is difficult to adhere to solder, has excellent wear resistance and oxidation resistance, and can withstand tens of thousands of uses.

[Effects of Investigation] As detailed above, according to the heating member of the present invention coated with a film made of a material that is insulating and has poor wettability with solder,
There is no current flow from the heating member to the workpiece, and solder is less likely to adhere, resulting in good processing.

[Brief explanation of the drawing]

1 to 5 all relate to embodiments of the present invention, FIG. 1 is a perspective view of one heating member, and FIG. 2 is a perspective view of one heating member.
Form drawing showing how several heating members are connected in series, No. 3
5 to 5 are schematic diagrams of an apparatus for manufacturing a heating member, FIG. 3 is a schematic diagram of an apparatus used in plasma CVD method, FIG. 4 is a schematic diagram of an apparatus used in sputtering method, and FIG. FIG. 5 is a schematic diagram of an apparatus used in the ECR plasma CVD method. 13... Heating member

Claims (1)

[Claims] In a member that processes a workpiece by heating it by applying electricity to a base material made of a conductive substance, at least the part of the base material in contact with the workpiece has a specific resistance of 10^-^2Ωc of the base material.
1. An electrically heated member characterized in that it is coated with a film having a contact angle of 10 degrees or more with a molten metal whose main component is at least one of lead and tin.