JPH0413149Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hot press device suitable for use in making predetermined connections between printed wiring boards having narrow-pitch conductive patterns.

[Conventional technology]

In recent years, with the miniaturization of electronic devices and electronic components, a large number of conductive patterns formed with narrow pitches are disposed on printed wiring boards, such as flexible printed wiring boards or rigid printed wiring boards. A technique has been proposed for easily and effectively connecting these conductive patterns to other conductive patterns arranged at narrow pitches, for example, provided on a flexible substrate.

Figure 8 shows narrow pitch conductive patterns 1, 1,...
This figure shows the connection state between a flexible printed wiring board 2 having conductive patterns 3, 3, . For the bonding part, an anisotropic conductive adhesive sheet 5 is used in which metal particles are dispersed in an insulating adhesive and the connection is made so that the sheet is insulating in the surface direction and conductive in the vertical direction of the sheet. ing. This anisotropic conductive adhesive sheet 5 is made by dispersing 10 volume parts of low melting point solder metal particles 5b in, for example, 100 volume parts of a solid part of a heat-melting insulating adhesive 5a. The composition is styrene-butadiene copolymer...50 parts by weight (Solprene 406, manufactured by Asahi Kasei Corporation) Terpene phenol resin...50 parts by weight (YS Polysta T130, manufactured by Yasushi Oil Co., Ltd.) Toluene...150 parts by weight Methyl ethyl ketone...50 parts by weight, and low melting point solder metal particles 5b are added to the Pb-Sn alloy.
The solder metal particles have an average particle size of 20 μm and have a melting point of 140°C by adding Sb and Bi.
In this connection process using the anisotropic conductive adhesive sheet 5, the anisotropic conductive adhesive sheet 5 is passed over at least the portion of each conductive pattern 3 on the substrate 4 that is to be connected to the corresponding conductive pattern 1. A flexible printed wiring board 2 is placed on top of the printed wiring board 2 so that the portions of the conductive patterns 1 and 3 to be connected to each other extend in the same direction and overlap with each other via the anisotropic conductive adhesive sheet 5, and then heated at 180°C using a hot press machine. Heat and press at 40Kg/cm ² for 30 seconds. In this case, the insulating adhesive 5a in the anisotropic conductive adhesive sheet
The insulating adhesive 5a that exists between the conductive pattern 1 and the conductive pattern 3 to which pressure is applied because it substantially protrudes from the mutually facing surfaces of both substrates because it exhibits fluidity when heated. Most of the adhesive is extruded to the side, and the extruded insulating adhesive wraps the conductive metal particles well, maintaining the insulation between adjacent patterns and forming the conductive pattern 1.
and the conductive pattern 3, the solder particles 5b
is melted and crushed by the heat and pressure applied by the hot press device (FIG. 9), and the conductive patterns 1 and 3 are soldered to connect them electrically and mechanically. For example, when the width of conductive patterns 1 and 3 is 0.1 mm and the interval between conductive patterns is 0.1 mm, the actual value of conductive resistance between opposing conductive patterns is 0.1 Ω or less, and the insulation resistance between adjacent connection parts is 10 It was ¹⁰ Ω or more.

[Problem that the invention attempts to solve]

By the way, in this heat-pressing process, the hot plate part 7 is fixed to the heater part 6 with screws 8, and the hot press device shown in FIGS. When connecting the conductive pattern 1 of the flexible printed wiring board 2 and the conductive pattern 3 of the rigid printed wiring board 4, at room temperature, the flatness of the pressed surface should be adjusted within the processing accuracy. However, when the heater is activated and the set temperature for use as a hot press (for example, 180°C to 300°C) is reached, the hot plate part 7
The heat escape is often uneven, and the difference in thermal expansion appears as distortion, which has the drawback of impairing the flatness of the press surface 7a. Further, since the hot plate part 7 is fixed to the heater part 6, there is a drawback that expansion and internal distortion due to heat cannot escape and become distortion of the hot plate part. Therefore, the accuracy of flattening of the press surface 7a produced at room temperature becomes completely meaningless at the actual operating temperature. When connecting a flexible printed wiring board 2 with a narrow-pitch conductive pattern and a rigid printed wiring board 4 in which the flatness of the pressed surface 7a is not maintained during thermocompression bonding, a pair of conductive patterns that are insufficiently pressed may occur, and their conductivity may be reduced. There was a problem that sex was no longer secured. This problem became more serious as the press surface became longer.

In view of this, it is an object of the present invention to provide a hot press device that can maintain the flatness of the press surface even during hot press bonding, thereby realizing accurate connection.

[Means for solving problems]

The present invention is a hot press device that heats with a heater 10 and presses the press surface 11a of the press body 9.
In the hot press device, the press body 9 is formed symmetrically around the heater 10 so as to apply pressure in a predetermined range.
A press surface 11a is formed on one side of the press body 9, and the press body 9 is held freely against thermal expansion.

[Effect]

In the hot press device of the present invention, one side of the press body 9 formed symmetrically around the heater 10 is used as the press surface 11a, so that heat conduction in the press body 9 is uniform, thermal expansion of the press body itself is uniform, and the press body 9 is formed symmetrically with respect to the heater 10. Since the body 9 is held freely without being constrained by thermal expansion, and the press body 9 is not constrained by thermal expansion, the flatness of the press surface 11a can be maintained well even during hot pressing, and even conductive patterns with narrow pitches can be accurately aligned. This allows a connection to be realized.

〔Example〕

An embodiment of the hot press apparatus of the present invention will be described below with reference to FIGS. 1 to 4. In these FIGS. 1 to 4, corresponding parts to those in FIGS. 8 to 11 are given the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 1, 9 indicates a press body, and this press body 9 is shown in FIGS. 2 and 3 with the heater 10 as the center.
As shown in the figure, it is formed symmetrically, for example, in a cylindrical shape, with a protrusion 11 for forming an elongated rectangular press surface 11a, and a side opposite to the side on which the press surface 11a is formed symmetrically with this protrusion 11. A protrusion 12 having a pseudo press surface 12a is integrally provided with the protrusion 12. In this press body 9, unlike the conventional one, a cylindrical heater 10 is fitted coaxially into the center of the press body, and is formed with high precision so that the heater 10 is located at the center of the press surface 10a and the pseudo press surface 12a. . Further, the material of this press body 9 is preferably a material with little thermal expansion, internal strain, etc. If internal strain remains, it is necessary to remove it in advance by heat treatment or the like. Also 13 and 1
Reference numeral 4 indicates a support portion that receives pressure from the bracket 15, and these support portions 13 and 14 are symmetrically provided in a band shape on the press body 9 so as to prevent uneven heat diffusion. Moreover, the bracket 15 supporting the press body 9 has a U-shaped cross section so as not to hinder the expansion of the press body 9, and when pressure P is applied from above, the lower ends 15a and 15b on both sides are connected to the both ends 13 of the press body. and 14 to lower the press body 9 by a predetermined distance. Here, 16,1
Receptacles 7 and 18 receive the support portions of the press body 9 while not restricting thermal expansion in the longitudinal direction, and the receptacles 16, 17 and 18 are fixed at predetermined positions on the bracket 15. The other parts shall be formed in the same manner as in conventional hot press equipment.

In this embodiment configured in this manner, a force P is applied from above the bracket 15, and the press surface 11a of the press body 9 comes into contact with a predetermined bonded portion, and then presses the bonded portion (see Fig. 4). With,
The heater 10 generates heat to a predetermined temperature to achieve uniform thermal expansion,
The heat from the cylindrical heater 10 for heat conduction is uniformly propagated to the symmetrically formed press surface 11a of the press body 9, so that the flatness of the press surface 11a is maintained during hot pressing. , predetermined conductive patterns 1 on printed wiring boards 2 and 4
and 3. Good electrical and mechanical connections will be made.

According to the above embodiment, the press surface 11a is formed on one side of the press body 9 formed symmetrically around the heater 10, so that thermal expansion is made uniform and the press body 9 is not restrained from thermal expansion. Since it is supported in this manner, there is an advantage that the flatness of the long hot press surface can be maintained as well as at room temperature. Therefore, the narrow pitch conductive pattern 1
Since the flatness of the hot-pressed surface is maintained even when the printed wiring boards in step 3 are connected to each other, the anisotropic conductive film is pressed over the entire surface, improving the conductivity between the opposing conductive patterns and the adjacent conductive patterns. Connections can be made in such a way that the insulation between each conductive pattern is well achieved.

Further, FIGS. 5 to 7 show other embodiments of the present invention. In these figures 5 to 7, figures 1 to 4
Portions corresponding to those in the figures are given the same reference numerals, and detailed description thereof will be omitted.

In this example, as shown in FIG. 5, the press body 9a is held between the slide member 21 and the bracket 15a with the heat insulating materials 19 and 20 interposed, and is pressurized with a force P from above in the figure, and heated with the heater 10. It is something to do. 6 and 7 show the press body 9a of this example. Since the press body 9a can be held from both sides in the longitudinal direction, the press body 9a is not provided with the support parts 13 and 14, unlike the example shown in FIG. .

It is easy to understand that the same effects as those of the above embodiment can be obtained in this example as well.

Further, the shape of the press body 9 is not limited to a cylindrical shape, but may be a symmetrical shape such as a polygon or an ellipse, with the heater 10 located at the center.

It goes without saying that the present invention is not limited to the above-described embodiments, and that various other configurations may be adopted without departing from the gist of the present invention.

[Effect of idea]

In this invention, a press surface is provided on one side of the press body formed symmetrically around the heater, so that heat conduction in the press body is uniform, the thermal expansion of the press body itself is uniform, and the press body is prevented from thermal expansion. Since the pressed body is held freely without restraint and is not restrained by thermal expansion, the flatness of the pressed surface can be maintained well even during hot pressing, and there is the advantage that accurate connection can be achieved even between conductive patterns with narrow pitches. .

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of the hot press device of the present invention, Fig. 2 is a perspective view showing an example of the main part of the example shown in Fig. 1, and Fig. 3 is a sectional view of the main part of the example shown in Fig. 1. ,
FIG. 4 is a line diagram showing the main parts of FIG. 3, FIG. 5 is a front view showing another embodiment of the present invention, and FIG. 6 is a perspective view showing an example of the main parts of the example shown in FIG. Figure 7 is the 6th
8 and 9 are diagrams showing examples of connections between printed wiring boards, and FIGS. 10 and 11 are diagrams showing examples of conventional hot press equipment. 9 is a press body, 10 is a heater, and 11a is a press surface.

Claims (1)

[Scope of utility model registration request] In a hot press device, the press body is formed symmetrically with respect to the heater, and the press body is heated by a heater and pressed in a predetermined range by the press surface of the press body. What is claimed is: 1. A hot press apparatus, characterized in that the press body is held freely against thermal expansion.