3 4
which is usually adhesive but is set when heated is pref- sion tape 20, Double coated-adhesive tape No. 532 erable for the application for the convenience of manu- made by Nitto Denko Corporation having a thickness facturing. For the conductor column 13, the usual sol- of 0.11 mm may be used.
dering pastes can be used, but an electrically conductive As shown in FIG. 4, at a first step, a number of pastes made of the conductive resin-vehicle with golden 5 through holes 24 each having a predetermined diameor silver powders dispersed therein is preferable. ter, 0.3 mm, are formed at a predetermined position.
Although the electrode 12 and the conductor column After the first step, an adhesion tape 20' with holes 24 is 13 are shown to be generally square-shaped in cross produced. The positions of the through hole 24 are section in FIG. IB, any other shapes such as rectangu- determined with respect to the position of electrodes 16 lar, circle, oval shape are also allowed. It is to be noted 10 on the substrate 11 (FIG. 7A). Each through hole 24 has that any of electric component parts such as resistors, a round shaped in cross section in this embodiment, but capacitors, coils, IC devices, other electric circuit any other shapes such as square, rectangular, and oval boards, or circuit board substrates can be provided on shape can be employed.
the substrate 11, but is omitted in FIGS. 1A and IB for At a second step, the second cover layer 236 is rethe sake of brevity. 15 moved from the adhesion tape 20' to expose the second
For mounting a single component, such as a resistor adhesion layer 216, producing an adhesion tape 20". or a capacitor, usually two electrodes 12 are necessary At a third step, the adhesion tape 20" is pressed on the electric circuit board CB. against the substrate 11 such that the second adhesion
For mounting an electric component module, an IC layer 216 contacts the substrate 11 with the through or an electric circuit board, several to several hundreds 20 holes 24 located on the corresponding electrodes 12. of electrodes are necessary on the electric circuit board Thus, the adhesion tape 20" can be firmly adhered to CB. It is to be noted that these electrodes are preferably the substrate 11 without any clearance therebetween, as arranged at the same plane of the electric circuit board shown in FIG. 5.
CB so that all of the electrodes can be electrically con- As shown in FIG. 6, at a fourth step, the through nected by a single processing step. 25 holes 24 are filled with an adhesive and electrical con
Referring to FIGS. 2A and 2B, the electric circuit ductive material, preferably made of the conductive board CB mounted on a printed circuit board is shown. resin-vehicle with golden or silver powders dispersed The printed circuit board PB includes a substrate 15 and therein, by a packing means 25 such as a squeegee, a plurality of electrodes 16 printed on the substrate 15 in Thus, the conductor columns 13 can be formed in a pattern for receiving the conductor columns 13, as 30 through holes 24, resulting in the electric circuit board shown in FIG. 2A. When the electric circuit board CB CB. It is to be noted that when the first cover layer 23a is placed on the printed circuit board PB, conductor is removed from the adhesion layer 20", the adhesion columns 13 contact and adhere to corresponding elec- layer 14 is obtained. The first cover layer 23a is preferatrodes 16. Then, when a pressure is applied on the elec- bly removed immediately before mounting the circuit trie circuit board CB, as shown by an arrow in FIG. 2B, 35 board on the printed circuit board PB, so as to keep the the full surface of the adhesion layer 14 firmly adheres first adhesion layer 21a and conductor column 13 from to the printed circuit board PB. Thus, both of electrodes contaminations by dust or other foreign matters.
12 and 16 are electrically connected through the con- It is to be noted that the conductor columns 13 and ductor columns 13 only by placing the electric circuit adhesion layer 14 can be formed by the technique of silk board CB on the printed circuit board PB with some 40 screen printing and injection by dispenser. The adhepressure. When compared with the conventional meth- sion tape 20' with through holes 24 can be used as a ods using molten solder, no heating is necessary to form mask pattern for forming of the conductor columns 13, the conductive columns 13. Therefore, the electric simplifying the manufacturing process and increasing components, substrates, and boards can be free from a the positional precision of conductor columns 13. high temperature. The time necessary to join electric 45 Therefore, connection errors such as short circuit becomponents to the electric circuit board is reduced. tween electrodes can be prevented. Additionally, the reliability of completed electric cir- Referring to FIGS. 7A, 7B, and 7C, the steps for cuit board is increased. mounting the electric circuit board CB obtained in a
It is, of course, possible to use the conductor column manner described above on a printed circuit board PB is
13 made of thermosetting material such as epoxy resin 50 described. First, the electric circuit board CB is placed where some mechanical strength is required for the over the printed circuit board PB such that conductor conductor column 13. Even in this case, the tempera- columns 13 are located over corresponding electrodes ture required to harden the thermosetting material is 16, as shown in FIG. 7A. Second, the electric circuit low enough to keep the electric components free from board CB is pressed against the printed circuit board PB the degradation. 55 so that the surface of the substrate 15 is adhered tightly
Referring to FIGS. 3, 4, 5, and 6, an example of to adhesion layer 21a, as shown in FIG. 7B. The adhemethod to form the conductor columns 13 arranged in sion layers 21a and 216, base layer 22 and conductor the adhesion layer 14 is described. column 13 are deformed to contact with each other
As shown in FIG. 3, an adhesion tape 20 includes a without any gap therebetween, as shown in FIG. 7C. base tape 22 made of resinous material. A first adhesion 60 Referring to FIGS. 8A, 8B, and 8C, an electric circuit layer 21a and a second adhesion layer 216 are provided board module CM according to the present invention is on the opposite surfaces of the base tape 22, respec- shown. The electric circuit board module CM is formed tively. Two cover layers, made of resinous material or by a substrate 36, a plurality of electrodes 32, a plurality paper, 23a and 236 having a thickness several to 75 jxm of conductor columns 33, and an adhesion layer 34 in a are provided on the first and second adhesion layers 21a 65 manner similar to that shown in FIG. 6. A first cover and 216, respectively, in a releasible manner. The adhe- layer 34a is not removed from the adhesion layer 34. A sion tape 20 having a thickness of approximately 50 jun protection layer 35, made of resinous material or paper, to 0.5 mm are preferable. As one example of the adhe- is additionally provided to cover the end surfaces of
