JP2010212592A - Circuit board and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board for improving yield by preventing solder balls from adhering to a conductor portion around a via portion by blocking the solder balls at a portion where a resist and a silk printing portion are stacked when an insulating substrate is immersed into a solder bath. <P>SOLUTION: The circuit board 1 includes: an insulating substrate 2; conductor portions 4 formed with a predetermined pattern on both surfaces of the insulating substrate 2 and conducting on both the surfaces of the insulating substrate 2 through a via portion 3 penetrating through the insulating substrate 2; a resist 5 for exposing a predetermined portion of each of the conductor portions 4 and covering the conductor portion 4; and a silk printing portion 6 for printing characters on the resist 5. In the circuit board, the resist 5 and the silk printing portion 6 are stacked to cover the conductor portion 4 around the via portion 3. The circuit board having the configuration described above provides significant effects that the yield in production of circuit boards is improved. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a circuit board having a via portion penetrating an insulating substrate and a manufacturing method thereof.

  FIG. 8 shows a cross-sectional view of a conventional circuit board having via portions. The circuit board 1 is provided with a via portion 3 penetrating the insulating substrate 2. Conductor portions 4 formed in a predetermined pattern are formed on both surfaces of the insulating substrate 2. The conductor portion 4 is electrically connected to both surfaces of the insulating substrate 2 through the via portion 3, and a predetermined position is exposed and covered with the resist 5. The insulating substrate 2 on which the conductor part 4 that is partially exposed is formed is immersed in a solder bath. As a result, solder is provided on the exposed conductor 4 and the electronic component is soldered.

Japanese Patent Laid-Open No. 7-170068 (pages 2 to 3 and FIG. 3)

  However, according to the conventional circuit board 1, the peripheral portion of the via portion 3 to which the electronic component is not attached is covered with the resist 5. At this time, the inner edge of the resist 5 is formed outside the inner edge of the conductor part 4 in the via part 3 in order to avoid the blockage of the via part 3 by the resist 5. When the insulating substrate 2 is dipped in a solder bath and taken out from the conductor 4 exposed on the inner peripheral side of the resist 5, a spherical solder ball B may adhere. Since the solder ball B has a small adhesion area, it is easily detached by an impact during the manufacturing process of the circuit board 1. For this reason, the short circuit of the circuit board 1 occurs due to the detached solder ball B, and the yield of the circuit board 1 is reduced.

  An object of this invention is to provide the circuit board which can improve a yield, and its manufacturing method.

  To achieve the above object, the present invention provides an insulating substrate and a conductor portion formed in a predetermined pattern on both surfaces of the insulating substrate and conducting on both surfaces of the insulating substrate through a via portion penetrating the insulating substrate. A circuit board comprising: a resist that exposes a predetermined portion of the conductor portion to cover the conductor portion; and a silk printed portion that prints on the resist; The conductor portion around the portion is covered.

  According to this configuration, the conductor portion that is covered with the resist and partially exposed is formed on the insulating substrate. The insulating substrate is immersed in the solder bath, and the electronic component is soldered by the solder attached to the exposed conductor portion. The conductor portion conducts on both surfaces of the insulating substrate through the via portion, and a resist and a silk print portion are laminated on the conductor portion around the via portion. As a result, when the insulating substrate is immersed in the solder bath, the solder balls are blocked by the laminated portion of the resist and the silk print portion, and the adhesion of the solder balls to the conductor portion around the via portion is prevented.

  According to the present invention, in the circuit board configured as described above, an inner edge of the conductor portion disposed in the via portion is covered with the resist or the silk print portion.

  According to the present invention, in the circuit board configured as described above, the resist and the silk-printed portion are laminated so that only one surface covers the conductor portion around the via portion. According to this configuration, the resist and the silk print portion are stacked on one surface around the via portion provided on the insulating substrate, and the resist and the silk print portion are not provided on the other surface and are opened.

  The present invention also includes a resist forming step of exposing a predetermined portion of the conductor portion provided on both surfaces of the insulating substrate having a through hole and covering with a resist, and a silk printing step of forming a silk printing portion to be printed on the resist. A circuit board manufacturing method comprising a flow soldering step of immersing the insulating substrate covered with a mask exposing a part of the conductor portion in a solder bath, wherein the through hole is provided with the conductor portion, A via portion is formed by electrically connecting the conductor portions on both sides of the insulating substrate, and the resist and the silk print portion are laminated on the conductor portion disposed around the via portion disposed at a position exposed by the mask. It is characterized by covering.

  According to the present invention, since the resist and the silk printed portion are laminated to cover the conductor portion around the via portion, the solder ball is blocked by the laminated portion of the resist and the silk printed portion when the insulating substrate is immersed in the solder bath. It is done. As a result, the solder balls are prevented from adhering to the conductor portions arranged around the via portions, so that it is possible to prevent a short circuit of the circuit board due to the falling off of the adhered solder balls. Therefore, the yield of the circuit board can be improved.

Side surface sectional drawing which shows the circuit board of 1st Embodiment of this invention. Side surface sectional drawing which shows the conductor part formation process of the circuit board of 1st Embodiment of this invention Side surface sectional drawing which shows the resist formation process of the circuit board of 1st Embodiment of this invention Side surface sectional drawing which shows the silk printing process of the circuit board of 1st Embodiment of this invention. Side surface sectional drawing which shows the flow soldering process of the circuit board of 1st Embodiment of this invention Side surface sectional drawing which shows the pattern of the resist of the circuit board of 1st Embodiment of this invention, and a silk printing part Side surface sectional drawing which shows the circuit board of 2nd Embodiment of this invention. Side sectional view showing a conventional circuit board

  Embodiments of the present invention will be described below with reference to the drawings. For convenience of explanation, the same parts as those in the conventional example shown in FIG. FIG. 1 is a side sectional view showing a circuit board according to the first embodiment. The circuit board 1 is provided with via portions 3 and 30 that penetrate the insulating substrate 2. Conductor portions 4 formed in a predetermined pattern are formed on both surfaces of the insulating substrate 2. The conductor portion 4 is electrically connected to both sides of the insulating substrate 2 through the via portions 3 and 30.

  The conductor portion 4 is exposed at a predetermined position and covered with a resist 5. The insulating substrate 2 on which the conductor part 4 that is partially exposed is formed is immersed in a solder bath. As a result, the solder 7 is provided on the conductor portion 4 exposed on one surface of the insulating substrate 2, and the electronic component 8 inserted through the via portion 30 is soldered.

  In addition, the surrounding conductor portion 4 is covered with a resist 5 on one surface of the via portion 3 through which the electronic component 8 is not inserted. A predetermined printing is provided on the resist 5 of the insulating substrate 2 by the silk printing unit 6. The silk printing portion 6 is provided by being laminated on a resist 5 provided on the conductor portion 4 around the via portion 3.

  2 to 5 show the manufacturing process of the circuit board 1. FIG. 2 shows a conductor portion forming step for forming the conductor portion 4 on the insulating substrate 2. A through hole 2a is formed in the insulating substrate 2 at a predetermined position. A metal film such as a copper foil is provided on both surfaces of the insulating substrate 2, and a conductor portion 4 having a predetermined pattern is formed by photolithography. At this time, a metal film is disposed on the inner wall of the through hole 2 a to form the via portions 3 and 30, and the conductor portions 4 on both surfaces of the insulating substrate 2 are conducted through the via portions 3 and 30.

  Next, FIG. 3 shows a resist forming process for forming a resist 5 on the insulating substrate 2. Sheet-like or liquid resist 5 is disposed on both surfaces of the insulating substrate 2 to cover the conductor portion 4. Then, the resist 5 is patterned so that the conductor portion 4 at a desired position is exposed by photolithography.

  Next, FIG. 4 shows a silk printing process for printing on the resist 5 of the insulating substrate 2. On the resist 5, printing by the silk printing unit 6 is performed at a predetermined position by silk printing.

  The resist 5 and the silk print portion 6 are laminated so as to cover the conductor portion 4 disposed around one surface of the via portion 3. At this time, as shown in FIG. 6, the inner diameter D2 of the pattern of the resist 5 and the silk print portion 6 is formed larger than the inner diameter D1 (for example, 0.35 mm) of the conductor portion 4 disposed in the via portion 3. (For example, 0, 5 mm). Then, the inner edge of the conductor part 4 disposed in the via part 3 is covered with the resist 5 or the silk printing part 6 as shown in FIG. The inner diameter D1 of the conductor part 4 and the inner diameter D2 of the pattern of the resist 5 and the silk print part 6 are set to dimensions that do not block the via part 3 by covering the inner edge of the conductor part 4.

  Next, FIG. 5 shows a flow soldering process for forming the solder 7 on the conductor portion 4. The insulating substrate 2 on which the resist 5 and the silk print portion 6 are formed is covered on both sides by a mask 10 having an opening 10a that exposes a via portion 30 into which an electronic component 8 (see FIG. 1) is inserted. The insulating substrate 2 provided with the mask 10 is immersed in a solder bath, and solder 7 is provided on the conductor portion 4 around the via portion 30. And the electronic component 8 is mounted in the via | veer part 30, and the circuit board 1 shown in FIG. 1 is obtained.

  The via part 3 arranged in the vicinity of the via part 30 in the flow soldering process is not provided with the electronic component 8, but is exposed from the opening 10a and contacts the solder in the solder bath. However, the resist 5 and the silk print portion 6 are laminated on the conductor portion 4 around the via portion 3. For this reason, as shown in FIG. 1, the insulating substrate 2 taken out from the solder bath is blocked from the spherical solder ball B by the resist 5 and the silk printing portion 6, thereby preventing contact with the conductor portion 4.

  A reflow soldering process for soldering chip-shaped electronic components may be provided. In the reflow soldering process, cream solder (not shown) is applied to the conductor portion 4 at a predetermined position in the portion where the mask 10 is disposed. Then, the insulating substrate 2 in which chip-shaped electronic components are placed on the cream solder is placed in a thermostatic bath, and the electronic components are soldered.

  According to the present embodiment, since the resist 5 and the silk printed portion 6 are stacked and the conductor portion 4 around the via portion 3 is covered, the solder ball B is resisted when the insulating substrate 2 is dipped in the solder bath and taken out. 5 and the silk printing portion 6 are blocked. Accordingly, the solder ball B is prevented from adhering to the conductor portion 4 disposed around the via portion 3, so that the circuit board 1 can be prevented from being short-circuited due to the drop of the adhered solder ball B. Therefore, the yield of the circuit board 1 can be improved.

  Further, since the inner edge of the conductor portion 4 disposed in the via portion 3 is covered with the resist 5 or the silk printing portion 6, the exposure of the conductor portion 4 disposed around the via portion 3 is prevented, and the solder ball B is attached. Can be prevented more reliably.

  Further, the resist 5 or the silk print portion 6 may protrude from the inner edge of the conductor portion 4 due to tolerance at the time of manufacture, and the via portion 3 may be blocked. At this time, since the resist 5 and the silk printed portion 6 are laminated and only one surface covers the conductor portion 4 around the via portion 3, the other surface of the via portion 3 is opened. For this reason, when the insulating substrate 2 is arranged in a thermostat with a reflow soldering process, the air in the via portion 3 escapes from the open surface, thereby preventing the occurrence of cracks in the insulating substrate 2 due to the expansion of air. Can do.

  Next, FIG. 7 is a side sectional view showing a circuit board according to the second embodiment. For convenience of explanation, the same parts as those in the first embodiment shown in FIGS. The present embodiment is different from the first embodiment in the arrangement of the resist 5 and the silk printing portion 6 around the via portion 3. Other parts are the same as those of the first embodiment.

  The inner diameter D2 of the pattern of the resist 5 and the silk printing portion 6 around the via portion 3 is larger than that of the first embodiment, and is formed at, for example, 0, 55 mm. Thereby, the inner edge of the conductor part 4 distribute | arranged to the via part 3 is exposed a little. Since the resist 5 and the silk printing part 6 are laminated on the conductor part 4 around the via part 3, the spherical solder ball B is blocked by the resist 5 and the silk printing part 6 in the insulating substrate 2 taken out from the solder bath. .

  According to the present embodiment, as in the first embodiment, since the resist 5 and the silk print portion 6 are stacked and the conductor portion 4 around the via portion 3 is covered, the insulating substrate 2 is immersed in the solder bath. The solder ball B is blocked by the laminated portion of the resist 5 and the silk printing portion 6. Accordingly, the solder ball B is prevented from adhering to the conductor portion 4 exposed around the via portion 3, so that the circuit board 1 can be prevented from being short-circuited due to the dropped solder ball B. Therefore, the yield of the circuit board 1 can be improved.

  In addition, although the inner edge of the conductor part 4 distribute | arranged to the via part 3 is exposed, the distance of the surface of the conductor part 4 and the surface of the silk printing part 6 leaves | separates by the resist 5 and the silk printing part 6 which were laminated | stacked. Thereby, adhesion of the solder ball B can be prevented. Moreover, blockage of the via part 3 due to the resist 5 and the silk printing 6 can be prevented.

  The present invention can be used for a circuit board having a via portion penetrating an insulating substrate.

DESCRIPTION OF SYMBOLS 1 Circuit board 2 Insulation board 3, 30 Via part 4 Conductor part 5 Resist 6 Silk printing part 7 Solder 8 Electronic component 10 Mask B Solder ball

Claims (4)

  An insulating substrate, a conductor portion formed in a predetermined pattern on both surfaces of the insulating substrate and conducting on both surfaces of the insulating substrate through a via portion penetrating the insulating substrate, and a predetermined portion of the conductor portion are exposed. In a circuit board comprising a resist covering the conductor part and a silk printed part printed on the resist, the resist and the silk printed part are laminated to cover the conductor part around the via part. A circuit board characterized by.   The circuit board according to claim 1, wherein an inner edge of the conductor portion disposed in the via portion is covered with the resist or the silk print portion.   The circuit board according to claim 2, wherein the resist and the silk print portion are laminated to cover the conductor portion around the via portion on only one surface.   A resist forming step of exposing a predetermined portion of the conductor portion provided on both surfaces of the insulating substrate having a through hole and covering with a resist; a silk printing step of forming a silk print portion to be printed on the resist; and And a flow soldering step of immersing the insulating substrate covered with a partly exposed mask in a solder bath, wherein the through-holes are disposed on both sides of the insulating substrate with the conductor portion disposed therebetween. Forming a via portion that conducts the conductor portion, and covering the conductor portion disposed around the via portion disposed at a position exposed by the mask by laminating the resist and the silk printing portion. A method of manufacturing a circuit board characterized by the above.

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