JPH0572177U - Circuit module with multi-layer substrate - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a circuit module using a multi-layer substrate, and it is an object of the present invention to enable easy formation of solder bumps and reduce the number of manufacturing steps of the circuit module. [Structure] A through hole 8 is provided in a first layer (outermost layer) 1-1 of a multilayer substrate 1, and an electrode pad 3 is provided and laminated on a second layer 1-2 thereunder. In this case, the electrode pad 3 is located at the same position as the through hole 8. Then, the solder 7 is put into the through hole 8, the conductor ball 6 is put thereon, and the conductor ball 6 is fixed by the solder 7 to form a solder bump.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a circuit module using a multilayer substrate that can be used as a module for an oscillator, an amplifier, a filter, or the like.

[0002]

[Prior Art]

 4A and 4B are explanatory views of solder bump formation in a conventional example. FIG. 4A is a circuit module before solder bump formation (cross-sectional view), FIG. 4B is a circuit module after dam formation (cross-sectional view), and FIG. 4C is solder. It is a circuit module (cross-sectional view) after bump formation.

In FIG. 4, 1 is a multilayer substrate, 2 is a circuit pattern (thick film conductor pattern), 3 is an electrode pad, 4 is a via (via hole), 5 is a dam, 6 is a conductor ball (metal). Balls) and 7 indicate solder.

Conventionally, circuit modules such as oscillators, amplifiers, and filters have been known as circuit modules using a multilayer substrate. When such a circuit module is formed into an SMD (Surface Mounted Component), solder bumps are formed on a part of the surface, and the solder bumps are used as external terminals.

Hereinafter, an example of a circuit module in which solder bumps are formed to form an SMD will be described with reference to FIG. First, as shown in FIG. 4A, predetermined circuit components are mounted on the multilayer substrate 1 to make a circuit module.

In this case, an electrode pad 3 is formed on the surface (outer side) of the multi-layer substrate 1, and the electrode pad 3 is covered with a via 4 (a through hole whose inside is filled with a conductor) 4. It is connected to the circuit pattern (thick film conductor pattern) 2.

Next, as shown in FIG. 4B, a dam 5 is formed around the electrode pad 3 formed on the surface of the multilayer substrate 1. The dam 5 is formed to prevent the solder from flowing out in the subsequent steps.

Thereafter, as shown in FIG. 4C, a solder (high-temperature solder) 7 is put inside the dam 5, and a conductor ball (for example, solder Cu, Al, etc.) 6 is further put on the dam 5, and the solder is put in the dam 5. By fixing the conductor balls 6 with 7, solder bumps are formed.

In this way, the conductor ball 6 is fixed to the surface of the multilayer substrate 1 and is electrically connected to the electrode pad 3. In this way, solder bumps can be formed on the circuit module. For example, the solder bumps are used as external terminals and used for mounting on the motherboard.

[0010]

[Problems to be solved by the device]

 The conventional device as described above has the following problems. (1) When forming solder bumps on a circuit module, it is necessary to make a dam. Therefore, the number of manufacturing processes is increased, which also causes an increase in product cost.

(2) The portion where the dam is formed cannot be used for other purposes, and the usable area is reduced accordingly. (3) When making a dam with a thick film, it is necessary to repeat the thick film forming process such as printing because the thickness does not reach a predetermined value with a single thick film formation. Therefore, the dam formation process requires a great deal of time and effort.

An object of the present invention is to solve such conventional problems and to easily form solder bumps, thereby reducing the manufacturing process of a circuit module.

[0013]

FIG. 1 is a diagram for explaining the principle of the present invention. FIG. 1A is a circuit module (cross-sectional view) before solder bump formation, and FIG. 1B is a circuit module after solder bump formation ( It is a cross-sectional view).

In FIG. 1, the same symbols as those in FIG. 4 indicate the same components. Further, 8 is a through hole, 1-1 is the first layer of the multilayer substrate, and 1-2 is the second layer. The present invention has the following configuration to solve the above problems.

(1) At least in a circuit module including a multilayer board in which solder bumps are provided on one surface of the multilayer board, a through hole 8 is provided in the first layer 1-1 which is the outermost layer of the multilayer board 1. On the second layer 1-2 which is an inner layer adjacent to the first layer 1-1, the electrode pad 3 connected to a predetermined circuit is provided at a position facing the through hole 8 and the through layer 8 is formed. Solder bumps 6 and 7 were provided in the holes 8.

(2) The solder bumps 6 and 7 of the above configuration (1) are used as external terminals for connecting to an external circuit. (3) The solder bumps 6 and 7 having the above configuration (1) are used as terminals for connecting to the components mounted on the multilayer substrate 1.

[0017]

[Action]

 The operation of the present invention based on the above configuration will be described with reference to FIG. When manufacturing a circuit module using a multi-layer substrate, through holes 8 are formed in the first layer 1-1 and the electrode pads 3 are formed in the second layer 1-2 in a step before stacking.

The electrode pad 3 is formed at a position corresponding to the through hole 8 while being connected to the internal wiring pattern 2 and the like. After that, the layers 1-1, 1-2, ... Are laminated, the solder 7 (high-temperature solder) is put into the through hole 8, the conductor ball 6 is put from thereover, and the solder 7 is fixed and fixed. I will

With this configuration, the first dielectric layer (or the insulating layer) around the through hole 8 functions as a dam when the solder 7 is inserted. Therefore, even if a dam is not provided for forming solder bumps, the solder does not flow out, the number of solder bump manufacturing steps is reduced, and the circuit module manufacturing steps are simplified.

[0020]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. 2 to 3 are views showing an embodiment of the present invention. FIG. 2 is an exploded perspective view of a circuit module before forming solder bumps, and FIG. 3 is an explanatory view of the circuit module when forming solder bumps. is there.

In FIGS. 2 and 3, the same reference numerals as those in FIGS. 1 and 4 indicate the same components. In addition, 1-n is the nth layer of the multilayer substrate, 9 is eutectic solder, and 10 is a mother board. In this embodiment, a circuit module such as an oscillator, an amplifier and a filter is realized by a multi-layer substrate and the circuit module is made into an SMD. In this example, a ceramic multilayer substrate was used as the multilayer substrate.

When the circuit module is made into an SMD, it is necessary to form an external terminal, but this external terminal is composed of a solder bump. As shown in FIG. 2, the circuit module before forming the solder bumps is composed of a multi-layer substrate including first layers 1-1 to n-th layers (n is an arbitrary integer).

The multi-layer substrate is a ceramic multi-layer substrate, and each of the first layer 1-1 to the n-th layer is a dielectric layer (or an insulating layer). A through hole (two through holes in this example) 8 is formed in the first layer (outermost layer of the multilayer substrate) 1-1, and a circuit pattern (thickness) is formed on the second layer 1-2. Electrode pads (thick film conductor pattern) 3 connected to the film conductor pattern 2 are formed.

The electrode pad 3 is formed by positioning so as to correspond to the position of the through hole 8 formed in the first layer 1-1. Therefore, the electrode pad 3 is located in the through hole 8 when the layers 1-1 to 1-n are stacked.

The through hole 8 is formed by punching or the like in a step before the step of laminating the green sheets that form the layers 1-1 to 1-n of the multilayer substrate. Further, the electrode pad 3 is also formed by printing a conductor paste or the like in the step before the step of laminating the green sheets (formed simultaneously with the pattern of the circuit pattern 2, capacitors, coils, etc.).

Then, after stacking and firing each green sheet, solder bumps are formed. When the circuit pattern 2 on the second layer 1-2 or the electrode pad 3 is connected to the circuit pattern formed on the third layer, the fourth layer or the like, or the circuit element (thick film element). There is also (not shown).

The cross section of the circuit module in the direction of the XY line in FIG. 2 is as shown in FIG. 3A. As shown in FIG. 3A, a through hole 8 is provided in the first layer 1-1 of the multilayer substrate 1, and an electrode pad is provided on the second layer 1-2 at a position corresponding to the through hole 8. 3 is provided.

From this state, as shown in FIG. 3B, the solder (high-temperature solder) 7 is put in the through hole 8, and the conductor ball (eg, Cu or Al ball) 6 is put thereon. Then, the conductor balls 6 are fixed by the melted solder 7, and the conductor balls 6 and the electrode pads 3 are electrically connected to form solder bumps.

In this case, since the first dielectric layer (or insulating layer) around the through hole 8 functions as a dam, the through hole 8 can be soldered without forming a dam as in the conventional case. And solder bumps can be formed.

FIG. 3C shows an example in which the solder bumps formed as described above are used as external terminals and the circuit module is mounted on a mother board. When the circuit module is mounted, the solder bumps are placed on the mother board 10 side (lower side in the figure) and placed on the mother board 10. Connect with the circuit pattern etc. on 10.

(Description of Other Embodiments) The embodiments have been described above, but the present invention can also be implemented as follows. (1) The solder bumps may be formed only by the solder (high-temperature solder) 7 without using the conductor balls 6 for the solder bumps.

(2) The solder bump may be used as an external terminal, but it can also be used as a terminal for connecting with a component mounted on the multilayer substrate 1. (3) The number of solder bumps may be any number.

(4) A circuit pattern (or a wiring pattern) or a thick film pattern (for example, a capacitor electrode pattern) of a circuit element is formed on the surface (outer surface of the outermost layer) of the multilayer substrate on which the solder bumps are formed. , A resistance pattern), or components such as a transistor and a chip capacitor.

However, when the solder bump is used only as an external terminal, a thick film pattern can be formed, but it is better not to mount a large component (eg, transistor, chip capacitor, chip coil, etc.). preferable.

(4) The multilayer substrate may be, for example, a glass-epoxy-based substrate in addition to the ceramic multilayer substrate.

[0036]

[Effect of the device]

 As described above, the present invention has the following effects. (1) When forming solder bumps, a dam is required to prevent the solder from flowing out.By providing a through hole in the outermost layer of the multilayer board, the same function as a conventional dam can be achieved. it can.

Therefore, the step of forming the dam becomes unnecessary, and the number of steps for manufacturing the circuit module is reduced and the process is simplified. (2) Since the manufacturing process is reduced, the cost of the product can be reduced.

(3) In order to make a conventional dam by the thick film technology, it was necessary to repeatedly perform thick film printing and the like, but in the present invention, it is not necessary to make such a dam, so The width reduces the number of manufacturing steps.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an exploded perspective view of a circuit module before forming solder bumps according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a circuit module when forming a solder bump in one embodiment.

FIG. 4 is an explanatory diagram when forming a solder bump in a conventional example.

[Explanation of symbols]

 1 Multilayer Substrate 1-1 to 1-4 Each Layer of Multilayer Substrate (1st to 4th Layers) 2 Circuit Pattern 3 Electrode Pad 4 Via (Via Hole) 6 Conductor Ball 7 Solder (High Temperature Solder) 8 Through Hole

Claims (3)

[Scope of utility model registration request] 1. A circuit module comprising at least a multilayer substrate, wherein solder bumps are provided on one surface of the multilayer substrate, wherein the first layer (1-1) which is the outermost layer of the multilayer substrate (1) comprises:
A through hole (8) is provided, and on the second layer (1-2) which is an inner layer adjacent to the first layer (1-1), a predetermined position is provided in the through hole (8). A circuit module using a multilayer substrate, characterized in that an electrode pad (3) connected to a circuit is provided and solder bumps (6, 7) are provided in the through hole (8). 2. The circuit module according to claim 1, wherein the solder bumps (6, 7) are external terminals for connecting to an external circuit. 3. The circuit module according to claim 1, wherein the solder bumps (6, 7) are terminals for connecting with components mounted on the multilayer board (1).