JP2016018800A - Printed board - Google Patents

Abstract

The problem of the present invention is solved by providing a printed circuit board with improved solder filling when soldering lead parts to through holes connected to an inner layer solid pattern such as a ground layer or a power supply layer. The The present invention relates to a substrate, an inner layer solid pattern formed in the substrate, a through hole formed in the substrate, and an upper layer of the substrate with respect to the inner layer solid pattern. Printed circuit board including another inner layer solid pattern connected to each other and via holes electrically connecting both inner layer solid patterns, and the former inner layer solid pattern is not directly connected to the through-hole, It is connected to the through hole through the via hole and the upper inner layer solid pattern, and the through hole is an opening for inserting a lead component on the upper side of the board, and the molten solder is located on the opposite side of the upper side of the board and through the molten solder. There is provided a printed circuit board characterized by having an opening for introduction into the board. [Selection] Figure 2

Description

  The present invention relates to a printed circuit board in which an inner layer solid pattern is connected to a through hole of an electronic circuit board, and solder filling into the through hole connected to the inner layer solid pattern is improved.

  In the soldering of the through-hole part as in the jet soldering process, the molten solder is supplied from the bottom side of the substrate or the electronic circuit board, and rises to the top surface of the substrate through the cylinder. While insufficient solder filling of the through holes is regarded as an important issue that reduces performance and reliability, sufficient solder filling with the formation of upper and bottom fillets is desired.

  Therefore, in the soldering process, sufficient heat to heat the entire through hole to the soldering temperature so that the molten solder reaches the top surface of the substrate while preventing the molten solder from solidifying and filling the through hole. And heat capacity is necessary for molten solder.

  This problem frequently occurs in a substrate in which through holes are connected to an inner layer solid pattern such as a ground wiring layer and a power supply wiring layer that lower the heat of molten solder inside the through holes. Ensuring this amount of heat is even more difficult for through-holes connected to multiple inner layer solid patterns because the entire through-hole is not heated and most of the heat is transferred to these layers. In addition, since the amount of heat supplied from the molten solder is limited, it is more difficult in the point soldering process or the selective soldering process.

As disclosed in Japanese Patent Application Laid-Open No. 2005-12088 (Patent Document 1), the solder filling to the through hole in the multilayer circuit board is not used in the vicinity of the thermal land from the through hole to the through hole in the soldering process. This is improved by controlling the directivity of the heat transferred to the inner solid pattern where the pad is patterned.
In Patent Document 1, in order to provide a multilayer circuit board with improved solderability when soldering and mounting a lead component to a through hole connected to a solid pattern such as a ground layer or a power supply layer, The copper non-use pad 29 which is suppressed by having the directivity of the heat moving from the through hole 26 when melting the metal is specified by inserting a lead component connected to the solid pattern 25 such as a ground layer or a power supply layer. It is described that the film is formed on the solid pattern 25 in the vicinity of the thermal land 27 to the through hole 26.

JP-A-2005-12088

  Since the through hole remains connected to the inner layer solid pattern as shown in FIGS. 1A and 1B of the prior art, it seems difficult to improve the solder filling of the through hole. 1A and 1B show a typical structure of a conventional circuit board having through holes. In the conventional circuit board illustrated in FIGS. 1A and 1B, each of the solid patterns 12 and 112 is directly connected to the through-hole electrode 110. In FIG. 1A, the upper surface of the solder supplied into the through hole by the soldering process has a height t from the bottom surface of the substrate 111, and the height t is lower than the position of the solid pattern 112. As shown in FIG. 1B, this phenomenon becomes a problem particularly when the plane of the solid pattern 112 is located near the bottom surface of the substrate 111. In this case, the heat from the molten solder during the soldering process rises up to the upper surface of the substrate 111 and does not heat the entire through-hole 113, but the heat from the molten solder during the soldering process does not pass through the through-hole electrode. Immediately moves to the solid pattern 112 through 110, and the molten solder rises only from the bottom surface of the substrate 111 to the height t into the through hole 113 into which the pin 21 of the electronic component 2 is inserted, resulting in soldering. In the case where the coupling portion 3 is formed, the directivity of heat transfer has no effect.

  FIG. 8 is a cross-sectional view of a lead component or pin coupled to a conventional substrate 121 having multiple inner layer solid patterns 112 a, 112 b, 112 c, 112 d connected to the through hole 123. Even in this case, the supply heat from the molten solder during the soldering process of the lead component 12 rises to the upper surface of the substrate 121 and does not heat the entire through-hole 123, but the molten solder during the soldering process. From the bottom surface of the substrate 121 to the height t ′ in the through hole 123 into which the pin 21 of the electronic component 2 is inserted. However, in the case where the solder joint portion 3 is formed as a result without increasing, the directivity of the heat transfer is not effective.

  The position of the inner layer solid pattern 112 was designed in consideration of electrical properties and thermal properties. Therefore, there is a need for a substrate structure that has not only thermal and electrical performance but also good solderability to the through hole.

  In order to solve the above-described problem, the present invention provides a substrate in which a plurality of layers are laminated, an inner layer solid pattern formed in the substrate, a through hole formed in the substrate, and the former inner layer solid pattern. On the other hand, a print having another inner layer solid pattern or wiring layer formed on the upper side of the substrate and directly electrically connected to the through hole, and a via hole formed in the substrate and electrically connecting both inner layer solid patterns. The inner solid pattern of the former is not directly connected to the through hole, but is connected to the through hole via the via hole and the upper solid pattern, and the opening of the through hole opposite to the upper side of the board is soldered. Provided to introduce the molten solder into the through hole in the process, and the opening of the through hole on the upper side of the board is for inserting the lead component into the through hole Providing a printed circuit board, characterized in that provided on.

  In order to solve the above-described problem, the present invention provides a substrate on which a plurality of layers are laminated, a first inner layer solid pattern formed on the substrate, a through hole formed in the substrate, and a first A second inner layer solid pattern formed on the upper side of the substrate with respect to the inner layer solid pattern, and a third inner layer formed on the upper side of the substrate with respect to the second inner layer solid pattern and directly electrically connected to the through hole. An inner layer solid pattern or wiring layer, a first via hole formed in the substrate and electrically connecting the first inner layer solid pattern and the second inner layer solid pattern, and a second inner layer formed in the substrate. A printed circuit board comprising a solid pattern and a second via hole that electrically connects the third inner layer solid pattern, wherein the first inner layer solid pattern is not directly formed in the through hole, but the first via hole, Ninouchi Connected to the through hole through the solid pattern, the second via hole and the third inner layer solid pattern, the second inner layer solid pattern is not directly to the through hole, but the second via hole and the third inner layer solid pattern. The through-hole opening opposite to the upper side of the board is provided to introduce molten solder into the through-hole in the soldering process, and the upper through-hole opening on the board is connected to the through-hole. Provided is a printed circuit board provided for inserting a component into a through hole.

  The present invention provides solder filling to through-holes connected to an inner layer solid pattern in a point soldering process or a selective soldering process without degrading the thermal and electrical performance of a board such as a printed circuit board. Can be significantly improved. The stepped structure of the present invention solves the same problem of solder filling in a substrate having multiple inner layer solid patterns.

It is sectional drawing of the lead component couple | bonded with the conventional board | substrate provided with the inner layer solid pattern connected to a through hole. It is sectional drawing of the lead component couple | bonded with the conventional board | substrate provided with the inner layer solid pattern connected to a through hole. FIG. 4 is a cross-sectional view of a lead component in which connection with a through hole is pushed up to the uppermost wiring layer by direct connection by a via hole and is coupled to a substrate of the present invention having an inner layer solid pattern. FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG. 2 including two via holes on both sides of the through hole or one via hole around the through hole. FIG. 3 is a cross-sectional view taken along the line A-A ′ of FIG. 2 including three or more via holes around the through hole. FIG. 5 is a cross-sectional view of a component that is connected to a substrate of the present invention having an inner layer solid pattern, with a connection with a through hole pushed up to an upper surface substrate or an upper surface substrate electrode. FIG. 6 is a cross-sectional view taken along the line A-A ′ of FIG. 5 of the present invention, with two via holes on either side of the through hole or one via hole around the through hole, and all the via holes are located in the top substrate electrode. FIG. 6 is a cross-sectional view taken along the line A-A ′ of FIG. 5 of the present invention, in which two via holes are provided on both sides of the through hole or one via hole is provided around the through hole, and the via hole is located outside the upper substrate electrode. It is sectional drawing of the board | substrate with which the lead component couple | bonded with the conventional board | substrate provided with the multiple inner layer solid pattern connected to a through hole was inserted. The figure which shows the cross section of the lead | read | reed components couple | bonded with the board | substrate of this invention provided with the multiple inner layer solid pattern connected through the via hole of step-like structure, and finally being connected to a through hole through the uppermost wiring layer. FIG. 10 is a cross-sectional view taken along the line AA ′ of FIG. 9 according to the present invention, which includes two via holes on both sides of the through hole or one via hole around the through hole, and the via hole is located second closest to the upper substrate surface. . FIG. 10 is a cross-sectional view taken along the line A-A ′ of FIG. 9 of the present invention, in which three or more via holes are provided around the through hole, and the via hole is located at a position closest to the upper substrate surface. FIG. 10 is a cross-sectional view taken along the line B-B ′ of FIG. 9 according to the present invention, in which two via holes are provided on both sides of the through hole or one via hole is provided around the through hole, and the via hole is located at a position closest to the bottom substrate surface. FIG. 10 is a cross-sectional view taken along line B-B ′ of FIG. 9 according to the present invention, in which three or more via holes are provided around the through hole, and the via hole is located at a location closest to the bottom substrate surface.

  The present invention relates to a substrate with improved solder filling in a through hole, a connection between an inner layer solid pattern and a through hole, and a stepped structure of the inner layer solid pattern. One feature of the present invention is to improve solder filling of substrates having through holes connected to the inner solid pattern. Another feature of the present invention is to improve solder filling of substrates having through-holes connected to multiple inner layer solid patterns.

  The present invention also relates to a substrate in which a plurality of layers such as a printed circuit board are laminated to improve solder filling in a through hole connected to the inner layer solid pattern, and the direct connection by the uppermost wiring layer and via hole in the printed circuit board. An inner layer solid pattern connected to the through hole via In the plane of the inner layer solid pattern, a cavity ring (copper-free ring) exists around the through hole, and is not connected to the through hole. In addition, since the connection between the inner layer solid pattern and the through hole is made in the uppermost wiring layer through the via hole connection, the heat from the molten solder passes through the inner hole through the via hole through the uppermost wiring layer connected to the through hole. It was set as the structure which reaches | attains a solid pattern.

  The object of the present invention is solved by a structure in which heat from molten solder in the soldering process is transferred to the entire through hole. In the plane of the inner layer solid pattern, a cavity ring (copper-free ring) exists around the through hole, and is not connected to the through hole. Further, the connection between the inner layer solid pattern and the through hole is pushed up to the uppermost wiring layer via the via hole connection so that the heat from the molten solder passes through the uppermost wiring layer and reaches the inner layer solid pattern by the direct connection by the via hole. Each of the present invention will be described in detail below.

  The present invention relates to a board with improved solder filling in a through hole connected to an inner layer solid pattern, and the inner layer solid pattern is like a printed circuit board through a direct connection by an uppermost wiring layer or an upper surface substrate electrode and a via hole. Connected to through-holes on the correct board. The present invention improves solder filling of substrates having through holes connected to the inner solid pattern. The present invention also improves solder filling of substrates having through holes connected to multiple inner layer solid patterns. Each of the present invention will be described in detail below.

  The substrate of the first embodiment is formed by laminating a plurality of layers L21 to L28, and the substrate connects the inner layer solid pattern 12a and the through hole 13 as shown in FIG. The inner layer solid pattern 12 a is connected to the through hole 13 in the substrate 1 through direct connection by the uppermost wiring layer 12 b and the via hole 14. The wall in the via hole 14 is formed by plating with a conductive material 141 such as copper plating in order to conduct heat conduction and electric conduction.

  The pin 21 of the electronic component 2 is inserted into the through hole 13 and connected to the through hole 13 by the solder 3 filled in the through hole 13. A conductive material 17 is formed in the through hole 13 and connected to the through hole electrodes 11 formed on both surfaces of the substrate 1.

  In the plane of the inner layer solid pattern 12a, there is a cavity ring (copper-free ring) 15 around the through hole 13, and there is no connection between the inner layer solid pattern 12a and the through hole 13 in the plane. Between the inner layer solid pattern 12a and the through hole 13 so that the heat from the molten solder on the bottom side of the substrate 1 in the soldering process finally heats the entire cylinder of the through hole 13 before moving to the uppermost wiring layer 12b. Is connected to the uppermost wiring layer 12b through the via-hole connection 14. Thereby, the molten solder rises to the upper surface of the substrate 1, and as a result, the solder joint portion 3 is formed after the soldering process. The connection between the inner layer solid pattern 12a and the through hole 13 becomes more important when performing a point soldering process or a selective soldering process in which the amount of heat supplied from the molten solder is limited.

  The ratio of the solder 3 filled in the through hole 13 reaches at least 50% which is the target filling ratio in the through hole 13 where the pin 21 of the electronic component 2 is inserted and connected to the inner layer solid pattern 12a. The uppermost wiring layer 12b of the embodiment is formed at a position less than 50% of the substrate thickness from the upper surface 16 of the substrate 1.

  The substrate 1 of the present invention may be configured to connect the inner layer solid pattern 12a and the uppermost wiring layer 12b with two or more via holes depending on applications.

  FIG. 3 shows an example of the A-A ′ sectional view of FIG. 2, and two via holes are provided so as to connect the inner layer solid pattern 12 a and the uppermost wiring layer 12 b. In the example shown in FIG. 2, two via holes are provided so as to connect the inner layer solid pattern 12a and the uppermost wiring layer 12b. However, it is also possible to provide only one via hole instead of the two via holes.

  On the other hand, FIG. 4 shows an example of the A-A ′ sectional view of FIG. 2, and a plurality of via holes (here, 12 via holes) are provided to connect the inner layer solid pattern 12 a and the uppermost wiring layer 12 b.

  Instead of being connected via the uppermost wiring layer 12b as described in FIG. 2, the inner layer solid pattern 121a is formed on the upper surface 16 of the substrate 501 on which a plurality of layers L51 to L58 are laminated as shown in FIG. Is connected to the through hole 13 through the upper substrate electrode 121b. The inner layer solid pattern 121a is connected to the upper surface substrate electrode 121b through the via hole 142. The wall of the via hole 142 is formed by plating with a conductive material 143 such as copper plating in order to conduct heat conduction and electric conduction.

  FIG. 6 is a cross-sectional view taken along line A-A ′ of FIG. 5, and two via holes 142 are formed on both sides of the through hole 13 and are located in the upper substrate electrode 121 b.

FIG. 7 shows another type of AA ′ cross-sectional view of FIG. 5, and two via holes 142 are provided on both sides of the through hole 13, and the via holes 142 are located outside the upper surface substrate electrode 121 b.
This method is applicable particularly when the uppermost wiring layer 12b is not required.

  The wall of the via hole 14 in the present invention is formed by plating with a conductive material 141 such as copper plating in order to conduct heat conduction and electric conduction.

  According to this embodiment, the inner layer solid pattern and the through hole are electrically and thermally connected indirectly via the via hole and the upper layer pattern directly connected to the through hole. Therefore, when supplying the molten solder to the through hole, heat is prevented from being taken away by the inner layer solid pattern having a relatively large heat capacity.

  As a result, the temperature of the through hole can be raised to a height sufficient to maintain the molten state of the solder, making it possible to ensure a sufficient solder filling ratio in the through hole and filling the through hole. It is possible to securely connect the solder to be soldered to the pin of the electronic component inserted into the through hole.

  As shown in FIG. 9, the second embodiment relates to a substrate in which a plurality of layers L91 to L96 are stacked and has multiple inner layer solid patterns 912a, 912b, 912c, and 912d. These inner layer solid patterns 912a, 912b, 912c, 912d are connected perpendicularly to the connection of via holes 914a, 914b, 914c, 914d like a stepped structure, and the connection of these multiple inner layer solid patterns 912a, 912b, 912c, 912d Is performed together with the uppermost wiring layer 912e as shown in FIG.

  A conductive material 917 is formed on the wall of the through hole 913 and connected to the through hole electrodes 910 formed on both surfaces of the substrate 911.

  Similarly to the substrate having the inner layer solid pattern shown in FIG. 2, the substrate having the multiple inner layer solid patterns 912a, 912b, 912c, and 912d so that the solder filling reaches at least the filling target ratio of 50% in the through hole 913. The uppermost wiring layer 912e in 911 is formed at a position less than 50% of the substrate thickness from the upper surface of the substrate 911.

  The uppermost wiring layer 912e is provided on the upper surface substrate electrode or the upper surface of the substrate connected to the upper surface substrate electrode. Any of the walls of the via holes 914a to 914d is formed by plating with a conductive material 9141a to 9141d such as copper plating in order to conduct heat conduction and electric conduction.

  The step-like structure in the present invention includes two or more step portions. FIG. 9 shows a stepped structure having four steps. Each part may be provided with two or more via holes that connect the inner layer solid pattern to the upper inner layer solid pattern depending on the application.

  FIG. 10 is a cross-sectional view taken along the line A-A ′ of FIG. 9, and two via holes are provided to connect the inner layer solid patterns 912 c and 912 d. On the other hand, FIG. 11 is a cross-sectional view taken along the line A-A ′ of FIG. 9, and a plurality of via holes (here, twelve via holes) are provided to connect the inner layer solid patterns 912 c and 912 d.

  FIG. 12 is a cross-sectional view taken along the line B-B ′ of FIG. 9, and two via holes are provided so as to connect the inner layer solid patterns 912 a and 912 b. On the other hand, FIG. 13 shows a B-B ′ cross-sectional view of FIG. 9, and a plurality of via holes (here, 20 via holes) are provided to connect the inner layer solid patterns 912 a and 912 b.

  According to this embodiment, the inner layer solid pattern and the through hole are indirectly electrically and thermally connected via the via hole and the uppermost layer pattern directly connected to the through hole. Therefore, when supplying the molten solder to the through hole, it is possible to prevent heat from being taken away by the inner layer solid pattern having a relatively large heat capacity.

  As a result, the temperature of the through hole can be raised to a height high enough to maintain the molten state of the solder, making it possible to ensure a sufficient solder filling ratio in the through hole and filling the through hole. This makes it possible to securely connect the solder to be soldered to the pin of the electronic component inserted into the through hole.

  The present invention is not limited to the above-described embodiments, and various improvements can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Printed circuit board 2 ... Electronic component 3 ... Through-hole solder joint 11 ... Through-hole electrode 12 ... Inner layer solid pattern, such as a ground power supply layer and a power supply wiring layer 12a ... Bottom inner layer Solid pattern 12b ... Uppermost wiring layer 12c ... Second bottom inner layer solid pattern 12d ... Third bottom inner layer solid pattern 12e ... Uppermost inner layer solid pattern 13 ... Through hole 14 ... Via hole 14a ... Bottom via hole 14b ... Second bottom via hole 14c ... Third bottom via hole 14d ... Top via hole

Claims (13)

A substrate on which a plurality of layers are laminated;
A first inner layer solid pattern formed in the substrate;
A through hole formed in the substrate;
A second inner layer solid pattern or wiring layer that is formed on the upper side of the substrate with respect to the first inner layer solid pattern and is electrically connected directly to the through hole;
A printed circuit board comprising a via hole formed in the substrate and electrically connecting the first inner layer solid pattern and the second inner layer solid pattern,
The first inner layer solid pattern is not directly connected to the through hole, but connected to the through hole via the via hole and the second inner layer solid pattern,
The through hole has an opening for inserting a lead component on the upper side of the substrate, and an opening for introducing molten solder into the through hole on the opposite side of the upper side of the substrate. substrate.   2. The printed circuit board according to claim 1, wherein the second inner layer solid pattern is formed in the substrate at a depth of less than 50% of the thickness of the substrate from the upper surface of the substrate.   The printed circuit board according to claim 1, wherein the second inner layer solid pattern is formed on a surface of the substrate.   The printed circuit board according to claim 1, wherein a distance between the through hole and the via hole is 0.1 mm or more.   The printed circuit board according to claim 1, wherein the via hole has a diameter of 0.05 mm or more.   The printed circuit board according to claim 1, wherein the first inner layer solid pattern and the second inner layer solid pattern are connected by a plurality of via holes. A substrate on which a plurality of layers are laminated;
A first inner layer solid pattern formed in the substrate;
A through hole formed in the substrate;
A second inner layer solid pattern formed on the upper side of the substrate with respect to the first inner layer solid pattern;
A third inner layer solid pattern or wiring layer formed on the upper side of the substrate with respect to the second inner layer solid pattern and electrically connected directly to the through hole;
A first via hole formed in the substrate and electrically connecting the first inner layer solid pattern and the second inner layer solid pattern;
A printed circuit board comprising a second via hole formed in the substrate and electrically connecting the second inner layer solid pattern and the third inner layer solid pattern,
The first inner layer solid pattern is not directly in the through hole, but through the first via hole, the second inner layer solid pattern, the second via hole, and the third inner layer solid pattern. Connected to
The second inner layer solid pattern is not directly connected to the through hole, but connected to the through hole via the second via hole and the third inner layer solid pattern,
The through hole has an opening for inserting a lead component on the upper side of the substrate, and an opening for introducing molten solder into the through hole on the opposite side of the upper side of the substrate. substrate.   The printed circuit board according to claim 7, wherein the third inner layer solid pattern is formed in the substrate at a depth of less than 50% of the thickness of the substrate from the upper surface of the substrate.   The printed circuit board according to claim 7, wherein the third inner layer solid pattern is formed on a surface of the substrate.   The printed circuit board according to claim 7, wherein a distance between the through hole and the second via hole is 0.1 mm or more.   The printed circuit board according to claim 7, wherein the diameters of the first via hole and the second via hole are 0.05 mm or more.   The first inner layer solid pattern and the second inner layer solid pattern, and the second inner layer solid pattern and the third inner layer solid pattern are connected by a plurality of via holes, respectively. 8. The printed circuit board according to 7.   The printed circuit board according to claim 7, further comprising four or more inner layer solid patterns connected vertically to the via connection of the stepped structure.

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