JP2004207647A - Method for manufacturing multilayer printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a multilayer printed circuit board for interlayer connecting by use of bumps. <P>SOLUTION: The method for manufacturing the multilayer printed circuit board comprises steps of: laminating a metal layer on which surface conductive bumps are formed on the other metal layer on which a circuit pattern is formed through an insulating resin layer; connecting the metal layers by the conductive bumps; positioning both the metal layers 10 and 20; temporarily installing a bump 14 selected out of the conductive bumps; and bonding the other bumps 13 out of the conductive bumps. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to a method for manufacturing a multilayer printed circuit board, and more particularly to a method for manufacturing a multilayer printed circuit board in which bumps penetrate an insulating resin layer interposed between metal layers in a multilayer printed circuit board and interconnect each metal layer.
[0002]
[Prior art]
As electronic devices have become smaller and more sophisticated, the density of circuit boards has increased, and high-density multilayer circuit boards have become widely used. As a general method for manufacturing a high-density circuit board, holes for interlayer connection called through holes and via holes are used.
[0003]
In this method, another gold image layer provided with an insulating resin layer is bonded to the lower substrate on which the circuit pattern is formed on the metal layer to form the upper substrate, and a mask corresponding to the circuit pattern of the lower substrate is prepared. An opening is formed in the upper substrate by applying a laser beam using this mask or by drilling with an NC machine or the like, and the opening is used as a conductive hole by metal plating to connect the metal layers. I try to make it. Thereafter, a circuit pattern is formed on the conductive layer of the upper substrate to form a multilayer circuit substrate.
[0004]
As an alternative to the through hole and via hole method, in recent years, for example, a bump is formed on one metal layer to be laminated, which is referred to as a B2it (registered trademark) technology disclosed in Patent Document 1, and an insulating resin layer is formed on the bump. To provide a connection with another metal layer by penetrating through.
[0005]
[Patent Document 1]
JP 06-342977 A [Patent Document 2]
JP 2001-111189 A [Patent Document 3]
Japanese Patent No. 2941182 [Patent Document 4]
Japanese Patent No. 3055496
[Problems to be solved by the invention]
In the above-mentioned B2it technology, it is necessary to fix the bumps of the upper substrate, which is opposed to the upper substrate, on the circuit substrate on which the circuit pattern is formed, with high positional accuracy. Usually, the substrates are fixed to each other temporarily by utilizing the adhesive force developed when the insulating resin layer interposed between the substrates is heated and softened. Alternatively, a solder paste is applied in advance to a part of the substrate, and the solder paste is soldered by spot heating to perform temporary attachment.
However, it is difficult to temporarily attach a substrate with a thermoplastic polyimide which is well known as such a material. In addition, there is a problem that the insulating resin flows even in the subsequent press bonding step to cause displacement. In the method using solder, an unnecessary solder paste is used.
[0007]
As for a technique for mounting a semiconductor device on a circuit board, Patent Literature 4 discloses a technique for mounting with high positional accuracy, but does not provide a technique applicable to circuit boards.
[0008]
The present invention has been made in consideration of the above points, and has as its object to provide a method of manufacturing a multilayer printed circuit board that performs interlayer connection using bumps.
[0009]
[Means for Solving the Problems]
To achieve the above object, the present invention provides:
A multilayer print in which a metal layer having a conductive bump formed on its surface is laminated on another metal layer on which a circuit pattern is formed via an insulating resin layer, and the metal layers are connected to each other by the conductive bump. In the method for manufacturing a substrate, the metal layer is aligned,
A method of manufacturing a multilayer printed circuit board, comprising temporarily attaching selected bumps in the conductive bumps and joining other bumps in the conductive bumps.
Is provided.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
1 (a) and 1 (b) show the first half steps of the method of the present invention. FIG. 1A shows a state in which a circuit board 20 on which a circuit pattern is formed is superimposed on a circuit board 10 on which bumps are formed.
[0011]
1A, a circuit pattern 12 is formed on a substrate 11 made of an insulating resin, a bump 13 is provided on the circuit pattern 12, and an end portion of the substrate 11 is formed. Another circuit pattern 16 is formed on the side, and a bump 14 is provided on this circuit pattern 16. The entire circuit patterns 12 and 16 and portions other than the tops of the bumps 13 and 14 are buried in the insulating resin layer 15.
[0012]
On the other hand, a circuit pattern 22 is formed on a substrate 21 made of an insulating resin on the circuit board 20 above FIG. 1A, and another circuit pattern 23 is formed near an end of the substrate 21. Have been.
[0013]
FIG. 1B shows a state in which the circuit board 10 and the circuit board 20 face each other with a slight gap therebetween while being positioned, and are about to be overlapped.
[0014]
FIGS. 2 (a) and 2 (b) show the latter half of the method of the present invention following the former half shown in FIGS. 1 (a) and 1 (b). FIG. 2A shows a state in which the circuit board 20 is placed on the circuit board 10 and then a concentrated load is applied to the downward arrow portion to join the bump 14 and the circuit pattern 23 to form a temporary attachment. Is shown.
[0015]
Subsequently, by pressing, the circuit board 10 and the circuit board 20 are integrated as shown in FIG. 2B, the circuit pattern 12 and the circuit pattern 22 are formed by the bumps 13, and the circuit pattern 16 and the circuit pattern 23 are formed by the bumps. The two-layered circuit board connected by the bumps 14 is completed. At the time of this pressing step, displacement between the upper and lower substrates is prevented by joining the previously provisionally attached bump and the circuit pattern 23.
FIGS. 3A and 3B show a bump 14 of the circuit board 10 and an example of a fitting structure of the circuit board 20 combined with the bump 14 in the above embodiment, and FIG. FIG. 3B is a vertical sectional view, and FIG. 3B is a bottom view of the fitting structure on the circuit board 20 side. This fitting structure is shown as an example of one bonding structure between the bump and the circuit board.
As shown in FIGS. 3A and 3B, the bumps 14 on the circuit board 10 have a columnar structure, the tops of which are circular planes, and the bumps 14 provided on the circuit pattern 23 on the circuit board 20 side. The combined structure is configured as a flat dish-shaped recess into which the top of the bump 14 fits. The circuit pattern 23 is circular in both the inner circumference and the outer circumference, and is provided with a metal layer depressed one step inside the inner circumference.
[0016]
Thus, when the top of the bump 14 is inserted into the recess of the circuit pattern 23, the circuit board 20 can be accurately positioned with respect to the circuit board 10 in accordance with the accuracy of the fitting portion. Then, the circuit pattern 16 and the circuit pattern 23 are electrically connected using the top surface of the bump 14 and a part of the peripheral surface.
[0017]
FIGS. 4A and 4B show another example of the fitting structure provided on the circuit board 20 combined with the bump 14 on the circuit board 10 side in the above embodiment, and FIG. 4A is a longitudinal sectional view, and FIG. 4B is a bottom view of the fitting structure on the circuit board 20 side.
[0018]
As shown in FIGS. 4A and 4B, the bumps 14 on the circuit board 10 form a mountain shape having a tapered surface 14b connected to the planar top 14a, and are provided on the circuit pattern 23 on the circuit board 20 side. The fitted structure thus formed has a ring shape in which the tapered surface 14b of the bump 14 is fitted. The circuit pattern 23 has a circular inner and outer circumference, and no metal layer is provided inside the inner circumference.
[0019]
As a result, the tapered surface 14b of the bump 14 abuts on the inner periphery 23a of the circuit pattern 23 in a ring shape, so that the center of the bump 14 and the center of the circuit pattern 23 overlap, and the circuit board 10 and the circuit board 20 are separated. Accurate positioning. In addition, by the ring-shaped abutting portion between the tapered surface 14b of the bump 14 and the circuit pattern 23 of the circuit board 20, the connection between the two circuit patterns is achieved and the temporary connection between the boards is achieved and the electrical connection is made.
[0020]
If the tapered surface 14 is formed so as to be in contact with the inner peripheral portion of the circuit pattern 23 before the circuit pattern 23 and the insulating resin layer 15 are in contact with each other, alignment by planar friction due to the tackiness of the resin or the like is performed. Positioning can be performed with higher accuracy without receiving difficulty or positional displacement due to friction between the upper and lower substrates.
[0021]
(Modification)
The fitting structure on the circuit board 20 side shown in FIG. 3 and FIG. 4 in the above embodiment has a ring shape. The alignment can be made more workable.
[0022]
【The invention's effect】
According to the present invention, as described above, a metal layer having a conductive bump formed on its surface is laminated on another metal layer on which a circuit pattern is formed via an insulating resin layer, and the metal layer is formed by the conductive bump. In manufacturing a multilayer printed circuit board by connecting them together, the two metal layers are aligned, a selected one of the conductive bumps is temporarily attached, and another one of the conductive bumps is joined. Therefore, the two circuit boards can be accurately and easily aligned and laminated.
[Brief description of the drawings]
FIGS. 1A and 1B are explanatory views of a first half of a process according to an embodiment of the present invention. FIG. 1A is a longitudinal sectional view of two circuit boards to be stacked, and FIG. FIG.
FIGS. 2A and 2B are explanatory diagrams of a latter half step in one embodiment of the present invention. FIG. 2A is a longitudinal sectional view of two circuit boards to be stacked, and FIG. FIG.
3 is an explanatory view showing an example of a fitting structure between circuit boards used in the method shown in FIGS. 1 and 2, FIG. 3 (a) is a longitudinal sectional view, and FIG. 3 (b) is a circuit board; The bottom view on the 20 side.
4 is an explanatory view showing another example of a fitting structure between circuit boards used in the method shown in FIGS. 1 and 2, FIG. 3 (a) is a longitudinal sectional view, and FIG. 3 (b). 2 is a bottom view of the circuit board 20 side.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Circuit board 11 Substrate 12 Circuit patterns 13 and 14 Bump 15 Insulating resin layer 16 Circuit pattern 20 Circuit board 21 Substrates 22 and 23 Circuit pattern

Claims (4)

A multilayer print in which a metal layer having a conductive bump formed on its surface is laminated on another metal layer on which a circuit pattern is formed via an insulating resin layer, and the metal layers are connected to each other by the conductive bump. In the method for manufacturing a substrate,
Aligning the metal layer,
Temporarily attaching a selected bump in the conductive bump,
A method of manufacturing a multilayer printed circuit board, wherein another bump in the conductive bump is joined. In the method for manufacturing a multilayer printed circuit board according to claim 1,
The method for manufacturing a multilayer printed circuit board, wherein the selected bumps are provided in advance for temporary attachment. The method for manufacturing a multilayer printed circuit board according to claim 1,
The method for manufacturing a multilayer printed circuit board, wherein the other gold image layer is provided with a connection structure that fits with the selected bump. The method for manufacturing a multilayer printed circuit board according to claim 3,
A method for manufacturing a multilayer printed circuit board, wherein the connection structure has a shape whose position can be identified.

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