Print circuit board

Abstract

To reduce warping of a print circuit board by suppressing the expansion of an insulation layer of the print circuit board due to a heat cycle at the time of use of conveyance, and prevent the occurrence of cracking.SOLUTION: A print circuit board comprises front surface mounting components 2 and 3 that are mounted on a front surface of a print circuit board 1. The front surface mounting component 3 comprises: a normal front surface mounting component 3a constructing an electronic circuit with the print circuit board 1; and a dummy front surface mounting component 3b that does not construct the electron circuit. The print circuit board 1 includes a non-mounting region IR of the normal front surface mounting component on the front surface. In the non-mounting region IR of the normal front surface mounting component, the dummy front surface mounting component 3b is mounted.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a printed wiring board having surface mounted components. [Background technology]

[0002] A conventional printed wiring board having surface mount components is known and disclosed, for example, in Patent Document 1. Fig. 2 is a plan view showing the conventional printed wiring board disclosed in Patent Document 1, where reference numeral 1 in the figure indicates a printed wiring board. As shown in the figure, the conventional printed wiring board 1 has a semiconductor chip 2 and a plurality of capacitors 3 as surface mount components, the semiconductor chip 2 being mounted in the center of the surface of the printed wiring board 1, and the capacitors 3 being mounted in the periphery of the surface of the printed wiring board 1.

[0003] This conventional printed wiring board 1 has build-up layers formed by alternating stacking of insulating layers and conductor layers on both sides of an insulating core substrate, and the conductor layers of these build-up layers connect a semiconductor chip 2 and a plurality of capacitors 3 to form an electronic circuit that performs a specified function. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-077729 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional printed wiring board 1 described above has multiple capacitors 3 mounted only on one side of the semiconductor chip 2 (the upper side in FIG. 2) of the peripheral area of ​​its surface. As a result, the insulating layer, which generally undergoes greater thermal deformation than the capacitors 3, expands and contracts in the peripheral area of ​​its surface on the side where the capacitors 3 are not mounted, due to heat cycles during transportation and use of the printed wiring board 1. Therefore, the conventional printed wiring board 1 has a problem in that it is prone to cracking because it repeatedly warps and returns to its original shape due to the expansion and contraction of the insulating layer in the peripheral area. [Means for solving the problem]

[0006] The printed wiring board of the present invention has a surface mount component mounted on a surface of the printed wiring board, the surface mount components include regular surface mount components which configure an electronic circuit together with the printed wiring board, and dummy surface mount components which do not configure the electronic circuit; the printed wiring board has a surface area on which the regular surface mount components are not mounted, The dummy surface mount components are mounted in the areas where the regular surface mount components are not mounted.

[0007] It is preferable that the regular surface mount components and the dummy surface mount components are positioned symmetrically with respect to a line that passes through the surface of the printed wiring board and bisects the surface.

[0008] It is also preferable that the dummy surface mount components are the same as the regular surface mount components. [Brief description of the drawings]

[0009] [Figure 1] 1 is a plan view showing an embodiment of a printed wiring board of the present invention. [Diagram 2] FIG. 1 is a plan view showing a conventional printed wiring board. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Fig. 1 is a plan view showing one embodiment of a printed wiring board of the present invention, and in Fig. 1, the same parts as in Fig. 2 are designated by the same reference numerals. That is, reference numeral 1 in the figure indicates a printed wiring board. The printed wiring board 1 of this embodiment has build-up layers formed by alternately laminating insulating layers and conductor layers, on both sides, for example, of an insulating core substrate.

[0011] Here, the conductor layers of the same build-up layer are electrically connected, for example, by via hole conductors that penetrate the insulating layer between the conductor layers, and the conductor layers of the build-up layers on both sides of the core substrate are electrically connected, for example, by through hole conductors that penetrate the core substrate between the build-up layers.

[0012] The printed wiring board 1 of this embodiment also has, as surface-mount components, a semiconductor chip 2 such as a CPU (Central Processing Unit) and a plurality of capacitors 3a, 3b. The printed wiring board 1 of this embodiment electrically connects the semiconductor chip 2 and the plurality of capacitors 3a, 3b, for example, by conductor layers of build-up layers on both sides of a core substrate, to form an electronic circuit that performs a predetermined function, such as processing high-frequency signals.

[0013] In the printed wiring board 1 of this embodiment, the semiconductor chip 2, which occupies a relatively wide area on the surface of the printed wiring board 1, is mounted on the center of the surface of the printed wiring board 1. Furthermore, a plurality of capacitors 3a, 3b, each of which is smaller than the semiconductor chip 2, are mounted on the periphery of the surface of the printed wiring board 1. The semiconductor chip 2 and the capacitors 3a, 3b may be mounted, for example, by soldering connection terminals to conductor pads exposed on the surface of the printed wiring board 1, or by other methods.

[0014] In the printed wiring board 1 of this embodiment, the plurality of capacitors 3a, 3b include not only the plurality of regular capacitors 3a as regular surface-mount components constituting the above-mentioned electronic circuit, but also a plurality of dummy capacitors 3b that do not constitute the above-mentioned electronic circuit. Each of the plurality of dummy capacitors 3b is substantially identical to each of the plurality of regular capacitors 3a, but is separated from the above-mentioned electronic circuit and does not function as a part of the electronic circuit.

[0015] The regular capacitors 3a are mounted only in a regular surface mount component mounting area RR, which is an area on one side (upper side in FIG. 1) of the semiconductor chip 2, in the peripheral area of ​​the surface of the printed wiring board 1. The dummy capacitors 3b are mounted only in a regular surface mount component non-mounting area IR, which is an area on the other side (lower side in FIG. 1) of the semiconductor chip 2.

[0016] The mounting area RR for regular surface mount components and the non-mounting area IR for regular surface mount components are positioned substantially symmetrically with respect to a center line CL which is a straight line passing through the surface of the printed wiring board 1 and dividing the surface into two equal parts. Each of the regular capacitors 3a and each of the dummy capacitors 3b are positioned substantially symmetrically with respect to the center line CL.

[0017] In the printed wiring board 1 of this embodiment, multiple dummy capacitors 3b are mounted in a regular surface mount component non-mounting area IR that is located substantially symmetrically with respect to the center line CL with respect to the regular surface mount component mounting area RR. Therefore, warping and return of the printed wiring board 1 caused by expansion and contraction of the insulating layer at the periphery of the printed wiring board 1 during transportation of the printed wiring board 1 or heat cycles during use are suppressed by the multiple dummy capacitors 3b even in the regular surface mount component non-mounting area IR, and are smaller than those of the conventional printed wiring board 1. Therefore, cracks are less likely to occur in the printed wiring board 1.

[0018] Moreover, in the printed wiring board 1 of this embodiment, each of the plurality of regular capacitors 3a and each of the plurality of dummy capacitors 3b are substantially identical to one another and are positioned substantially symmetrically with respect to the center line CL. Therefore, warping and return of the printed wiring board 1 caused by expansion and contraction of the insulating layer at the periphery of the printed wiring board 1 due to heat cycles during transportation and use of the printed wiring board 1 are effectively suppressed by the plurality of dummy capacitors 3b, and are smaller than those of the conventional printed wiring board 1. Therefore, cracks are less likely to occur in the printed wiring board 1.

[0019] Although the above description is based on the illustrated embodiment, the present invention is not limited to this, and in the present invention, for example, the surface mount components may be other electronic components such as resistors instead of the semiconductor chip 2 and the multiple capacitors 3a and 3b. Also, at least one of the regular surface mount components and the dummy surface mount components may be one instead of multiple.

[0020] Furthermore, in the present invention, for example, printed wiring board 1 may be a printed wiring board having a build-up layer on one side of a core substrate, a coreless build-up wiring board that does not have a core substrate, or a printed wiring board of a simple configuration in which one conductor layer is formed on one side of an insulating substrate. [Explanation of symbols]

[0021] 1 Printed wiring board 2. Semiconductor chips 3. Capacitor 3a regular capacitor 3b Dummy Capacitor CL center line IR Regular surface mount component non-mounted area RR Regular surface mount component mounting area

Claims

1. A printed wiring board having surface mount components mounted on a surface of the printed wiring board, the surface mount components include regular surface mount components which configure an electronic circuit together with the printed wiring board, and dummy surface mount components which do not configure the electronic circuit; the printed wiring board has a surface area on which the regular surface mount components are not mounted, The dummy surface mount components are mounted in the areas where the regular surface mount components are not mounted.

2. 2. The printed wiring board according to claim 1, The regular surface mount component and the dummy surface mount component are positioned symmetrically with respect to a line that passes through the surface of the printed wiring board and bisects the surface.

3. 2. The printed wiring board according to claim 1, The dummy surface mount components are similar to the regular surface mount components.

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