JPH0422157A - High-frequency heating apparatus - Google Patents

Abstract

PURPOSE:To execute a heating operation with good efficiency and uniformly while the shape of an object having a fine size is being maintained with high accuracy by a method wherein a heating plate composed of a ferromagnetic substance is pushed to the prescribed position of an object to be heated and the heating operation is executed. CONSTITUTION:At a high-frequency heating plate 10 which is composed of a dust core 1, an induction heating coil 2, a heating plate 4 and the like, the coil 2 composed of a hollow flat-type copper wire is wound on the core 1, and the plate 4 composed of a Cr ferromagnetic substance is brought into contact with its one face. A pressure plate 6 is arranged and installed so as to be faced with the coil 2 and can press a lead-frame continuous body (an object to be heated) F to the direction of the plate 4 by using actuators 21. The plate 6 is moved to the direction of the plate 4. While regions excluding side rails of a lead frame are being pressed, the plate is heated. When the plate 4 is pushed to the prescribed position of the object F to be heated and is heated in this manner, it can be heated with good efficiency. Since it can uniformly be heated and it is heated while it is being pressed, its shape can be corrected and the shape can be worked with high acuracy.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a high frequency heating device.

(Prior Art) As the density and integration of semiconductor devices increases, the number of lead pins increases, but paracanes tend to remain the same as before or become smaller.

As the number of inner reats increases within the same area, the width of the inner reams and the distance between adjacent inner reams naturally become narrower. For this reason, the inner lead may change due to a decrease in strength, and the deformation may cause a short circuit between the inner two.

In particular, when molded by lead frame or stamp pink, 0.1 to 0.1-2 for a plate thickness of 0.15 mm.
It is necessary to punch out a millimeter wide punch, and even if stamping is done without any problems, internal residual stress will affect the subsequent culm, resulting in deformation and short circuits due to the slight external force applied to it. There is.

This also applies when shape processing is performed using Enotink.
This has become a problem.

However, in recent years, semiconductor devices have been becoming smaller and smaller, and it has become impossible to sufficiently suppress the deformation of inner leads, which have become thinner and finer.

Therefore, in order to remove such internal residual stress and harden the surface, a method has been proposed in which the lead frame is heated in a neutral atmosphere furnace after shaping, and then slowly or rapidly cooled.

As this heating means, a high frequency induction heating type heating device as shown in FIG. 7 is used.

This device is configured so that a predetermined space is sandwiched between heating coils 2 wound around a dust core 1, and a lead frame, which is an object to be heated, is run within this space.

However, with such conventional equipment, because the shape and dimensions (width, area) of the lead frame are partially different, it is not possible to perform uniform heating, but on the contrary, distortion due to thermal stress may occur. There were some drawbacks. Also, at most 15
There was a problem in that the temperature could only be raised to 0 to 200°C, and sufficient surface hardening could not be achieved.

Further, there were problems in that it took a long time to raise the temperature, the thermal efficiency was poor, and even if wrinkling occurred, it would continue to harden.

(Problems to be Solved by the Invention) As described above, as semiconductor devices become more highly integrated, the lead width and spacing are becoming smaller and smaller. A heat treatment method was desired.

This has been a problem when forming not only lead frames but also other devices that require microfabrication.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a small-sized heating device that can efficiently and uniformly heat a minute object while maintaining its shape with high accuracy.

[Structure of the invention]

(Means for Solving the Problems) Therefore, the heating device of the present invention is equipped with a heating means configured by bringing a heating plate made of a ferromagnetic material into contact with one surface of an induction heating coil, and the heating plate of this heating means is , is configured to press a predetermined position of the object to be heated and heat it.

Preferably, first and second heating means configured by bringing a heating plate made of a ferromagnetic material into contact with one surface of the induction heating coil are disposed facing each other, and the first and second heating means are arranged opposite to each other. The heating plate is configured to press at least one of the heating plates against a predetermined position of the object to be heated to perform heating.

(Function) According to the present invention, the heating plate made of a ferromagnetic material is pressed against a predetermined position of the object to be heated to perform heating. ,
It becomes possible to uniformly heat even a heated object that is localized in area. In addition, since it is heated in a fixed state, there is little deformation, and even if it is twisted, it can be corrected and a good shape can be obtained.

In addition, by bringing it into contact with a heating plate heated by high frequency heating, it is possible to heat efficiently.
The heating area can be made smaller, making it possible to obtain a small and highly reliable heating device.

(Example) Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing a high frequency heating device according to an embodiment of the present invention.

This heating device connects a winding device (shown) having an additional function of tensioning and a winding device (not shown) having an additional function of tensioning. The lead frame is configured to perform high-frequency heating on a predetermined region of the lead frame while being conveyed at a high frequency, and is composed of a high-frequency heating section 10 and a cooling section 20.

As shown in an enlarged sectional view of the main part in FIG. 2, the high-frequency heating section 10 includes a heating plate 4 made of a Cr ferromagnetic material on one side of an induction heating coil 2 made of a hollow rectangular copper wire wound around a dust core 1. and a suppressing plate 6 arranged opposite to the heating means 5 and configured to be able to press the lead frame in the direction of the heating means 5 by the actuator 21. The suppression plate 6 is moved in the direction of the heating plate 4 of the heating means, and while pressing the area of the lead frame excluding the site rail,
configured to heat.

Further, the cooling unit is disposed opposite to the first cooling plate 20a, and is configured such that the lead frame can be suppressed in the direction of the first cooling plate 20a by the actuator 21. a second cooling plate 20b configured, moving the second cooling plate 20b in the direction of the first cooling plate 20a,
The lead frame is configured to cool while pressing the heated area.

Here, 7 is a guide pin, 8 is a mask plate for heating only a desired area, and 9 is a support plate.

Next, a method for manufacturing a lead frame using this heating device will be explained.

FIG. 3(a) to FIG. 3(e) are diagrams showing the manufacturing process of a lead frame according to an embodiment of the present invention.

First, as shown in FIG. 3(a), a strip-shaped material is processed by the stamping method so that the tip of the inner lead 24 facing the die pad 22 is slightly connected to the adjacent inner lead by a connecting piece T. Mold into.

Next, a coining process is performed to ensure a flat width at the tips of the inner leads, and then this lead frame F is mounted on the high frequency heating device shown in FIG. Here, the thickness of the tip of the inner reed after coining is 0.12 mm.

While the lead frame F is intermittently conveyed between the winding device having a tension adding function and the winding device having a tension adding function of this device,
Perform heating. Here, while pressing the pressure plate toward the heating plate by the actuator 21, the heating plate is heated at 600°C for 1 second using high-frequency heating, and the area of the lead frame excluding the site rail is heated via the heating plate. Heat. Thereafter, the pressure on the press plate is released by the actuator 21, and the 1-pisotilito frame is transported to the heating section and the cooling section, where it is rapidly cooled in the cooling section 20.

At this time, the high frequency heating section 10 performs heating of adjacent units in parallel.

FIG. 3(b) shows the region R treated by this high-frequency heating.

Thereafter, as shown in FIG. 3(C), a predetermined plating process, taping process, etc. are performed to punch out the connecting pieces, and the tips of the inner leads are separated to complete the lead frame.

After placing the semiconductor chip on the die pad 22 of this lead frame, the semiconductor chip and the lead frame are electrically connected by wire bonding.

Then, the semiconductor device is completed through a resin sealing process, a tie bar cutting process, and an outer lead molding process.

The lead frame formed in this way is hardened by quenching using heat, and the internal stress caused by shape processing is also removed, and deformations such as twisting are corrected, resulting in extremely high precision. Because it is possible to maintain good positional relationship between REITs and each other,
Not only short circuits between REITs are prevented, but short circuits with the Hong Kong wire are also prevented, resulting in extremely high reliability. Further, the thickness of the lead frame may be less than 0.15 mm.

Furthermore, since the connecting pieces are removed after reinforcing with insulating tape, the inner lid can have a narrower gluing width at its tip.

This allows the tip of the inner reel to be brought closer to the die pad, reducing the amount of Honda ink wire used. Therefore, manufacturing costs are reduced. Furthermore, the Hong Kong wire can be shortened and short circuits are prevented.

Furthermore, in the above embodiment, the lead frame is formed while being connected by the connecting pieces, and after pasting the insulating tape,
Although the connecting pieces are removed, it goes without saying that the present invention can be molded without leaving any connecting pieces or can be applied to a single frame.

In addition, in the above embodiment, a wire phone deink type glue is used.
Although the description has been made for lead frames, it is also applicable to direct bonding lead frames.

In the above embodiment, the high-frequency heating section 10 is provided with a heating means only on one side, and the other side is constituted by a pressing plate, but as shown in a modified example in FIG. Heating means 5 configured by bringing a heating plate 4 made of Cr ferromagnetic material into contact with one surface of the rotated induction heating coil 2
It is also possible to arrange two heating means 5a and 5b facing each other, and heat the lead frame while sandwiching and pressing the lead frame between the two heating means 5a and 5.

Moreover, as shown in FIG. 5, instead of the dust core 1, Cr
The induction heating coil 2 may be wound directly around the heating plate 4 made of ferromagnetic material, and the first and second heating means 5a and 5b may be provided.

Alternatively, as shown in FIG. 6(a), two high-frequency heating sections 10a and 10b may be arranged side by side in the running direction of the lead frame at a predetermined pitch. The heating area at this time is shown in FIG. 6(b).

Here, only the die pad and inner lead are heated.

In addition, in the above embodiment, Cr was used as the heating plate, or
In addition, any ferromagnetic material such as nickel may be used.

In addition, in the embodiment described above, the shape processing of the lead frame has been described, but it goes without saying that the present invention is not limited to lead frames and can be applied to other devices.

〔Effect of the invention〕

As explained above, according to the present invention, the heating plate made of a ferromagnetic material is pushed into a predetermined position of the object to be heated to perform heating, so that efficient heating can be achieved. In addition, it becomes possible to uniformly heat objects to be heated whose widths, areas, etc. are locally different. In addition, since heating is performed without pressing, the shape can be corrected, and highly accurate shape processing is possible.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a high-frequency heating device according to an embodiment of the present invention;
The figures are enlarged views of the main parts of the device, Figures 3 (a) to 3 (
e) is a diagram showing the manufacturing process of a lead frame according to an embodiment of the present invention, FIGS. 4 to 6 (a) are explanatory diagrams of main parts of a device according to other embodiments of the present invention, and FIG. 6 (b) Figure 6(a)
FIG. 7 is a diagram showing a conventional heating device. F. Lead frame, 1. Dust core, 2. Induction heating coil, 4. Heating plate, 5. Heating means, 7. Kite pin, 8. Mask plate, 9. Support plate, 10.
- High frequency heating section, 20... Cooling section, 20a... First cooling plate, 20b... Second cooling plate, 2]
Actuator, 22... Die pad, 24. Inner lead, 28... Outer lead, 29 Support 7\
-T-・Connection piece. Applicant's agent Takahisa Kimura Fig. f9 Stokori Fig. Fig. 1 (table 1) Fig. 7 Procedural amendment (method) % formula % Name of the invention Relationship to the case of the person who amends the high-frequency heating device Patent Applicant Mitsui Hytic Co., Ltd. 7, Contents of Amendment (1) In the specification of the present application, in the fifth line of the third vane, "through FIG. 3(e)" is corrected to "through FIG. 3(C)."

Claims (2)

[Claims] (1) Equipped with a heating means configured by a heating plate made of a ferromagnetic material brought into contact with one surface of an induction heating coil, and heating the object by pressing the heating plate of the heating means against a predetermined position of the object to be heated. A high frequency heating device characterized by being configured as follows. (2) First and second heating means configured by bringing a heating plate made of a ferromagnetic material into contact with one surface of the induction heating coil are disposed facing each other, and the first and second heating means are arranged opposite to each other. A high-frequency heating device characterized in that a heating plate is configured to press a predetermined position of an object to be heated while heating it.