JP2646329B2 - Method for manufacturing multilayer bump connection board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a multi-layer bump connection board, and more particularly to a method of manufacturing a multi-layer bump connection board having high reliability without peeling even after a thermal history.

[0002]

2. Description of the Related Art Conventionally, in a method of manufacturing a multilayer bump connection board of this kind, as shown in FIG. 3, a plurality of resin boards on which components are mounted in advance are connected by solder bumps and laminated, and then melted. 2. Description of the Related Art A multilayer bump connection substrate in which solder bumps are connected using a low-temperature solder material is known.

That is, in FIG. 3, a comparison is made between a lower-layer circuit pattern 2 which is a part of a circuit pattern formed on a lower-layer resin substrate 1 on which components are mounted and an intermediate-layer resin substrate 4 having an intermediate-layer circuit pattern 21. High melting point 221 ° C
The bump portions formed using the tin-silver eutectic solder material are brought into contact with each other, the temperature is increased while applying pressure to the surface of the substrate, and the substrates are bonded via the high-melting-point circuit pattern bump bonding portion 5.

Further, the surface layer side resin substrate 6 having the intermediate layer side circuit pattern 22 is melted at a relatively low temperature of 183 ° C.
The bump portions formed using the tin-silver eutectic solder material are abutted, the temperature is increased while applying pressure, the solder is re-melted, and the bumps are bonded to each other to form three composite substrates. According to such a manufacturing method, it is possible to obtain a high-density mounting substrate in which electric components are three-dimensionally attached to the lower resin substrate 1 and the surface resin substrate 6.

[0005]

Conventionally, this kind of multi-layer bump connection board has a connection portion located at a peripheral portion of a high melting temperature solder bump board connected first after a thermal history such as a heat cycle has passed. Had the disadvantage that cracks were easily generated in the steel.

That is, when a low-temperature side tin-lead eutectic solder material having a melting point of 183 ° C. is used to increase the temperature while applying pressure to perform bump bonding, stress generated by thermal expansion of the resin substrate is concentrated on the end face of the bonded substrate. The high-melting-point circuit pattern bump bonding portion 5 made of tin-silver eutectic solder on the high-temperature side, which is exposed to a high-temperature region, exhibits a low tensile strength. There was a phenomenon that the crystal became coarser than the portion 52. As a result, when a thermal history such as a heat cycle is added, the tin-silver crystal solder bump portion on the high-temperature side in the end region of the bonded substrate has a problem that fatigue fracture is likely to occur.

An object of the present invention is to provide a method of manufacturing a multilayer bump connection board which solves the above-mentioned problems of the prior art.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention relates to a method of forming a plurality of resin substrates each having a bump joint provided on a circuit portion and a circuit pattern by using a high melting point. In a method of manufacturing a multilayer bump connection board in which bump bonding is performed while pressing using a solder material of the following, and then bump bonding is performed while pressing using a solder material having a low melting point, peripheral portions of the end surfaces of a plurality of resin substrates are provided. The method is characterized in that a bump bonding portion is also provided, and after laminating and bonding a plurality of resin substrates, a peripheral portion of a crystal-enlarged end face is cut and removed.

[0009]

The present invention relates to a manufacturing method in which a bump bonding portion is provided in a peripheral portion of an end face of a plurality of resin substrates, and after laminating and bonding the plurality of resin substrates, a peripheral portion of the crystal-enlarged end face is cut and removed. Even if the thermal history is added, even if fatigue fracture occurs in the tin-silver eutectic solder bump on the high-temperature side of the bonded substrate end region, the tin-silver eutectic on the high-temperature side of the bonded substrate end region Since the solder bumps are removed by cutting, a highly reliable method for manufacturing a multilayer bump connection board can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS.

In FIG. 1, a part of a lower-layer circuit pattern 2 formed on a lower-layer resin substrate 1 on which components such as a capacitor and an IC are mounted and a bump bonding pattern 3 around a lower-layer substrate and an intermediate-layer circuit pattern 21 are formed. The intermediate layer side resin substrate 4 having a part and the intermediate layer side substrate peripheral region bump bonding pattern 31 is heated while applying pressure using a tin silver eutectic alloy solder material having a relatively high melting point of 221 ° C. Then, bonding is performed via the high melting point circuit pattern bump bonding portion 5 and the high melting point substrate peripheral region bump bonding portion 51.

A part of the intermediate-layer-side circuit pattern 22 of the intermediate-layer-side resin substrate 4 and the intermediate-substrate-side-substrate peripheral-area bump bonding pattern 32, and a part of the surface-layer-side circuit pattern 23 of the surface-layer-side resin substrate 6 and the surface-layer-side Using a solder material of a tin-silver eutectic alloy having a relatively low melting point of 183 ° C., the temperature is increased while applying pressure to the low-melting point circuit pattern bump bonding section 7 and the low-melting point. The three-layer resin composite substrate is completed by bonding via the point substrate peripheral region bump bonding portion 71. Further, using a router machine or the like, the substrate is separated from the portion of the cut removal surface 8 indicated by the dotted line, and the bonded bump portion around the edge of the substrate is removed.

According to such a manufacturing method, the difference in thermal expansion between the substrates caused by the bonding and pressing of the substrates,
Concentration of stress in the area around the end face of the board caused by flattening, etc., due to the pressing of the displacement of the board warpage, and cutting and removing the crystal coarse area of the high-temperature solder material caused by the rise in temperature during bonding of the low-temperature solder material. Becomes possible. Pressing,
When increasing the temperature, the lower resin substrate, the intermediate resin substrate,
Both the surface layer side resin substrate and the bump bonding portion are provided in the same area with respect to the vertical plane which is the Z-axis direction in the cross-sectional configuration, so that a uniform pressing condition can be given at the time of pressing, thereby suppressing crystal coarsening of the solder material. To help you.

FIG. 2 is a cross-sectional explanatory view showing the uniform pressing of the cross-sectional structure, in which the intermediate layer side pressure equalizing pattern 9, the surface layer side pressure equalizing pattern 91, and the low melting point pressure equalizing bump bonding to the pressing surface. Through the portion 72, the crystal coarsening of the high melting point circuit pattern bump bonding portion 5 can be suppressed.

An embodiment will be described below. Using a stainless steel screen on a FR-4 resin substrate having a circuit pattern of copper foil and a bump junction of a high melting point substrate having a diameter of 0.3 mm and using a stainless screen, a tin-silver eutectic alloy solder claim is screen printed and components are mounted and soldered. Create a bump.

Further, a circuit pattern made of copper foil and 0.3 mm
FR-4 resin substrates having bump joints with a diameter on both sides of the substrate are aligned and abutted through pin guide holes and the like, pressurized at 20 kg / cm ² , heated in a nitrogen atmosphere, and bumped. Join. Furthermore, the circuit pattern of copper foil and 0.
A tin-lead eutectic alloy solder claim is screen-printed on an FR-4 resin substrate having a 3 mm-diameter bump joint on both sides and one side of the substrate via a solder screen, and reflowed to form a solder bump. Next, the solder bumps are abutted by positioning them through the above-described pin guide holes, and 20 kg / cm.
The pressure of ² is applied, and the temperature is raised in a nitrogen atmosphere to bond the three resin co-crystal alloys. Thereafter, external processing is performed by using a router machine, and a peripheral bump-dedicated area made of a silver-tin eutectic alloy having a coarse crystal which has become a stress concentration area at the end of the substrate from a predetermined circuit portion is cut and removed.

Further, a bump-dedicated area around the substrate to be cut and removed is bump-bonded with a solder material having a melting point different from that of the substrate used in advance, and the substrate bonding surface is observed with a cross-sectional microscope to observe the tendency of crystal growth. Thus, a constant area value is determined. Further, the generated stress can be measured and derived from the substrate portion using, for example, a strain gauge.

In this type of method, a large number of components are mounted and multilayered, so that a wide variety of solders having different melting points such as tin-copper eutectic alloy, tin-lead eutectic alloy, bismuth / lead / tin alloy, and indium / tin alloy are used. It is also effective in a configuration using a material. In particular, a remarkable effect is obtained when a lead material having a large mechanical extensibility, such as a tin-silver eutectic solder alloy described in this embodiment, is used on a high temperature side under a high temperature condition without using a large amount of indium. It becomes possible.

In the embodiment described above, MILSTD883
D at -55 ° C for 5 minutes, high temperature at + 125 ° C for 5 minutes
In the liquid phase thermal shock test, the three-sheet bump bonded substrate using only the tin-silver eutectic alloy was subjected to almost 3000 cycles, and the bump bonded substrate according to the conventional example using the tin-silver eutectic alloy and the tin-lead eutectic alloy was: After about 1,800 times, the tin-silver eutectic alloy and the bump joints caused fatigue fracture. The sample made of the tin-silver eutectic alloy according to the embodiment of the present invention actually obtained a resistance of almost 3000 cycles.

[0020]

As described above, according to the present invention, in a plurality of bonded substrates bump-bonded by using solder materials having different melting points, a region dedicated to bump bonding is provided around the edge of the substrate to form a multilayer structure. Since this manufacturing method cuts and removes a certain area, it is possible to manufacture a highly reliable multi-layer bump connection substrate without any peeling even after a thermal history such as a heat cycle.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view illustrating a method for manufacturing a conventional multilayer bump connection substrate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lower layer side resin board 2 Lower layer side circuit pattern 21, 22 Intermediate layer side circuit pattern 23 Surface layer side circuit pattern 3 Lower layer side substrate peripheral area bump joint pattern 31, 32 Middle layer side substrate peripheral area bump joint pattern 33 Surface layer side substrate Peripheral area bump bonding pattern 4 Intermediate layer side resin substrate 5 High melting point circuit pattern bump bonding part 51 High melting point substrate Peripheral area bump bonding part 52 High melting point substrate Central area bump bonding part 6 Surface layer side resin substrate 7 Low melting point Circuit pattern bump joint part 71 Low melting point substrate peripheral area bump joint part 72 Low melting point equalizing bump joint part 8 Cutting removal surface 9 Intermediate layer side equalizing pattern 91 Surface layer side equalizing pattern

Claims (2)

(57) [Claims] A plurality of resin substrates each having a bump bonding portion provided on a circuit portion and a circuit pattern are bump-bonded while pressing using a high-melting-point solder material. In a method of manufacturing a multilayer bump connection board for performing bump bonding while pressing using a solder material, a bump bonding portion is also provided around an end surface of the plurality of resin substrates, and after the plurality of resin substrates are stacked and bonded, crystal coarseness is increased. A method for manufacturing a multilayer bump connection board, characterized by cutting and removing the peripheral portion of the end face. 2. The method according to claim 1, wherein peripheral portions of the end faces of the resin substrate are coaxially stacked and arranged.