JP2006186149A - Printed circuit board and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed circuit board capable of improving reliability wherein, even when an insulation board material and a conductor pattern are expanded/shrinked due to heat and the expansion/shrinkage results in land exfoliation, this does not lead to breakage of the conductor pattern, and to provide an electronic apparatus. <P>SOLUTION: Through-holes 30 and via-holes 31 are formed to a multilayer printed circuit board 21 (four layers) onto which insertion type electronic components 3 are mounted. A conductor 33 forming the inner wall of each through-hole 30 electrically connects lands 23A of a board front side to lands 26A of a board rear side. Similarly, a conductor 34 forming the inner wall of each via-hole 31 also electrically connects lands 23B of the board front side to lands 26B of the board rear side. Further, an inner layer pattern 25B electrically connects the through-holes 30 and the via-holes 31. Electrodes 4 of each electronic component 3 are inserted to the through-holes 30 and electrically connected to the conductor 33 by unleaded solder 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printed circuit board on which an insertion type electronic component is mounted, and an electronic apparatus including the printed circuit board.

  In recent years, from the viewpoint of environmental protection, so-called lead-free solder that does not use lead, which is an environmental pollutant, has been increasingly used for printed circuit boards of electronic devices.

  As lead-free solders that do not use lead, Sn-Ag solder, Sn-Ag-Cu solder, Sn-Ag-Bi-Cu solder, Sn-Cu solder, and the like have been proposed and put into practical use. However, such a lead-free solder has a higher melting point (190 to 230 ° C.) than that of lead solder, and stress relaxation is unlikely to occur. Therefore, in the through hole 2 formed in the printed circuit board 1 as shown in FIG. When the electrode 4 of the insertion-type electronic component 3 is inserted and the through hole 2 and the electrode 4 are electrically connected by the lead-free solder 5, there is a problem that a connection failure peculiar to lead-free solder is likely to occur (for example, non-patent Reference 1). This poor connection is caused by the fact that the conductor portion (copper foil) 9 forming the inner wall of the through hole 2 and the front surface land 7 and the rear surface land 8 formed on the front and back surfaces of the insulating base 6 are separated from the insulating base 6. It is known that this phenomenon occurs due to peeling (lift-off phenomenon = land peeling phenomenon) or cracks in the lead-free solder 5 itself. As a result, since the electronic device does not operate, it has been an obstacle when the printed circuit board 1 using the lead-free solder 5 is applied to a mounting substrate of various electronic devices. In addition, 10-12 are the conductive patterns formed in the inside and the back surface side of the insulating base material 6, and 13 and 14 are the solder resists formed on the front and back surfaces of the insulating base material 6.

  In FIG. 5, the electrodes 4 of the insertion type electronic components 3A and 3B are inserted into the two through holes 2A and 2B, respectively, and the through holes 2A and 2B and the insertion type electronic components 3A and 3B are electrically connected by lead-free solder 5, respectively. It is sectional drawing which shows the other conventional example of a printed circuit board. In the printed circuit board 17, the two through holes 2 </ b> A and 2 </ b> B are electrically connected by the back side conductive pattern 12 formed on the back side of the insulating base 6. In addition, a via hole 16 including a through hole is formed in the insulating base 6, and the via hole 16 and the through hole 2 </ b> A are electrically connected by the back surface side conductive pattern 12.

  Also in the printed circuit board 17 having such a structure, the front-side lands 7a and 7b and the back-side lands 8a and 8b are peeled off from the insulating base material 6 due to the expansion and contraction of the lead-free solder 5 due to heat, There was a problem that a crack occurred or the conductive pattern 12 on the back surface side was peeled off from the back surface of the insulating base material 6 and disconnected.

  Conventionally, various countermeasures against the land peeling phenomenon caused by the lead-free solder 5 during soldering have been proposed (see, for example, Patent Documents 1 and 2).

  The substrate described in Patent Document 1 includes a conductor part and a resist part formed on the surface of a base material, and forms an extension part that covers a part of the conductor part on the resist part (over resist method), The remaining part excluding the part of the conductor part is used as a land for electrically connecting the electronic component. According to the substrate employing such an over-resist method, the extended part of the resist part holds down a part of the conductor part, so that the land can be prevented from peeling off from the substrate surface without being lifted off. it can.

  The circuit board described in Patent Document 2 is a multi-layer circuit board manufactured by a subtractive method, and by inserting lead-free solder through the through-holes of electrodes of insertion-type electronic components, The formed first and n-th layer surface circuits, the through holes and the electrodes are electrically connected, and the inner layer is not electrically connected to the inner layer circuit at a position in contact with the inner wall of the through hole inside the substrate. A land is formed.

  According to such a circuit board, the joint surface between the inner wall of the through hole and the prepreg is divided by the inner layer land in the thickness direction of the circuit board. Therefore, the joint surface between the corner portion of the through hole and the inner layer land is divided. The bonding length can be shortened. Thereby, since the shear stress produced by the thermal expansion coefficient difference of the thickness direction of a circuit board can be made small, generation | occurrence | production of the wall peeling from which the wall part of a through hole leaves | separates from a prepreg can be suppressed. Also, by preventing such wall peeling, stress concentration at the corners of the through holes of the first and nth layers can be alleviated, and cracks that penetrate lead-free solder occur at the corners of the through holes. Or the surface land can be prevented from peeling off.

Nikkei Electronics 7/31, 2000 p. 27) JP 2002-246734 A JP 2003-218534 A

However, in Patent Document 1, in order to cover a part of the land with the resist, it is necessary to form the land larger than a normal size. For this reason, there is a problem that the space between adjacent lands is narrowed and other conductor portions are difficult to pass.
There is also a problem that if the resist printing accuracy is low and the resist extension is short due to printing misalignment, the resist is not over-resisted and lands are easily peeled off.

  In Patent Document 2, when the adhesion length from the through hole to the inner layer land is shortened, the shear stress caused by the difference in thermal expansion coefficient can be reduced when the electronic component is soldered. Since the expansion and contraction of the substrate and the electrode cannot be suppressed completely, there is still a problem that connection failure still easily occurs.

  The present invention has been made to solve the above-described conventional problems, and the object of the present invention is to expand the insulating base material and the conductive pattern by heat when soldering the electronic component to the through hole with lead-free solder. An object of the present invention is to provide a printed circuit board and an electronic device which can prevent a connection failure of a conductive pattern even if the land is peeled off due to shrinkage and can improve the reliability of soldering. .

  In order to achieve the above object, the printed circuit board according to the first invention covers and protects at least three layers of conductive patterns respectively formed on the front and back surfaces of the insulating base material and the conductive patterns on the front and back surfaces of the base material. Solder resist, at least a first through hole that is formed on the insulating base material and electrically connects the conductive pattern on the front and back sides of the base material and the conductive pattern on the inner side of the base material, and the electrode is the first through hole. An insertion type electronic component inserted into a hole and electrically connected by lead-free solder, and a conductive pattern on the substrate surface side electrically connected to the first through hole via a conductive pattern on the substrate inner side And at least a first via hole for electrically connecting the conductive pattern on the back side of the substrate.

  The printed circuit board according to a second aspect of the present invention is the printed circuit board according to the first aspect of the present invention, further formed on the insulating base material and electrically connecting the conductive pattern on the front and back surfaces of the base material and the conductive pattern on the inner side of the base material. A through hole is provided, and the first and second through holes are electrically connected via a conductive pattern on the inside of the base material, and an electrode of an insertion type electronic component is inserted into the second through hole to lead-free. Electrically connected by solder.

  The printed circuit board according to a third aspect of the present invention is the printed circuit board according to the first aspect, further formed on the insulating base material, for electrically connecting the conductive pattern on the front and back surfaces of the base material and the conductive pattern on the inner side of the base material. A through hole and a second via hole, and an electrode of an insertion-type electronic component is inserted into the second through hole and electrically connected by lead-free solder; the second through hole and the second via hole; Are electrically connected by a conductive pattern on the inside of the substrate, and the first via hole and the second via hole are electrically connected via a conductive pattern on the substrate surface side or the substrate back surface side. It is.

  An electronic device according to a fourth invention includes the printed circuit board according to the first, second, or third invention.

  In the first invention, when the electrode of the insertion-type electronic component is inserted into the first through hole and connected by lead-free solder, the wall of the first through hole is peeled off due to expansion and contraction of the lead-free solder, It is expected that poor connection will occur due to land peeling and lead-free solder cracks. On the other hand, since the first via hole is a hole formed for the purpose of establishing an electrical interlayer connection of the conductive pattern and the inner wall is plated, the first via hole is formed when the electronic component is soldered to the first through hole. No wall peeling or land peeling occurs, and disconnection of the conductive pattern can be prevented. Moreover, since the conductive pattern of the inner layer connecting the first through hole and the first via hole is sandwiched between the layers of the base material, it is not deformed or disconnected by the heat of lead-free solder. Therefore, even when wall peeling or land peeling occurs on the first through hole side, there is no influence on the electrical connection between the first through hole and the first via hole, and the electrode is connected to the first through hole. It is possible to reliably connect to the first via hole through one through hole and the inner layer conductive pattern.

  In the second invention, since the conductive pattern of the inner layer that electrically connects the first and second through holes is sandwiched between the layers of the base material, it is not deformed or disconnected by the heat of lead-free solder, Through holes can be securely connected to each other.

  In the third invention, since the conductive pattern of the inner layer that electrically connects the first through hole and the first via hole is sandwiched between the layers of the base material, it is deformed or disconnected by the heat of the lead-free solder. There is no. Similarly, since the conductive pattern of the inner layer that electrically connects the second through hole and the second via hole is sandwiched between the layers of the base material, it is not deformed or disconnected by the heat of lead-free solder. Therefore, the second through hole and the second via hole can be reliably connected. Since the conductive pattern on the outer layer side that electrically connects the first and second via holes is separated from the through hole, the conductive pattern is hardly affected by heat during soldering, and is peeled off or disconnected from the base material. There is nothing.

  In the fourth invention, since the printed circuit board according to the first, second, or third invention is provided, there is no generation of a defective product due to disconnection of the conductive pattern, and the reliability of the electronic device can be improved. Examples of the electronic device include various electronic devices such as a television receiver, a personal computer, and a measuring device.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
FIG. 1 is a cross-sectional view of a main part in a state where an electronic component showing a first embodiment of a printed circuit board according to the present invention is mounted. In the figure, 21 is a printed circuit board on which an insertion type electronic component 3 having an electrode 4 is mounted.

  The printed circuit board 21 is composed of a multilayer printed circuit board having a four-layer structure manufactured by a known subtractive method, so that the insulating base 6 and the first layer formed on the surface of the insulating base 6 are formed. Conductive pattern 23 (23A, 23B), second and third layer conductive patterns 24 (24A to 24C) and 25 (25 to 25C) formed inside insulating base 6, and back surface of insulating base 6 The conductive pattern 26 (26A to 26C) of the fourth layer formed on the front surface and the solder resists 13 and 14 formed on the front and back surfaces of the insulating substrate 6 are formed.

  The conductive patterns 23A and 23B of the first layer are exposed on the surface side of the insulating base 6 to form surface-side lands (hereinafter also referred to as surface-side lands or outer layer patterns). Each of the second layer conductive patterns 24A to 24C forms, for example, a ground circuit (hereinafter also referred to as an inner layer pattern). Each of the third layer conductive patterns 25A to 25C forms, for example, a power circuit (hereinafter also referred to as an inner layer pattern). The conductive patterns 26A and 26B of the fourth layer are exposed on the back side of the insulating substrate 6 to form lands on the back side (hereinafter referred to as back side lands). The conductive pattern 26 </ b> C forms an outer layer pattern and is covered with the solder resist 14.

  The insulating substrate 6 is formed by impregnating kraft paper, polyester fiber, etc. with epoxy resin, phenol resin, etc., and then drying the solvent to attach a copper foil to the three prepregs to perform etching treatment. After the fourth conductive patterns 23 to 26 are formed, these prepregs are stacked and bonded by hot pressing.

  The through hole 30 includes a through hole that penetrates the insulating base material 6, the front surface land 23 </ b> A, the inner layer pattern 25 </ b> B, and the back surface land 26 </ b> A, and is plated on the inner wall and the front and back surfaces of the insulating base material 6. Conductors 33, 33a and 33b made of copper foil are formed. The conductors 33, 33a, and 33b electrically connect the front surface side land 23A, the back surface side land 26A, and the inner layer pattern 25B.

  The via hole 31 includes a through-hole penetrating the insulating base material 6, the front side land 23 </ b> B, the inner layer pattern 25 </ b> B and the back side land 26 </ b> B. A conductor 34 made of copper foil is formed. The conductor 34 electrically connects the front surface side land 23B, the back surface side land 26B, and the inner layer pattern 25B. Therefore, the via hole 31 and the through hole 30 are electrically connected through the inner layer pattern 25B. The via hole 31 is formed in order to connect the electrical layers of the conductive pattern, and is not used as a mounting hole for the insertion type electronic component 3. The back surface land 26B may or may not be covered with the solder resists 13 and 14.

  The insertion-type electronic component 3 is composed of an electronic component including an electrode 4, for example, a connector. The electrode 4 is inserted into the through hole 30 and electrically and mechanically connected to the through hole 30 by lead-free solder 5. Therefore, the electrode 4 is electrically connected to the front side lands 23A, 23B, the back side lands 26A, 26B, and the outer layer pattern 26C via the lead-free solder 5, the conductor 33, the inner layer pattern 25B, and the conductor 34, respectively. Yes. As the lead-free solder 5, lead-free solders such as Sn—Zn, Sn—Ag, and Sn—Cu are used.

  As described above, the printed circuit board 21 according to the present invention includes the through hole 30 that electrically connects the electrode 4 of the insertion-type electronic component 3, the front surface land 23A, and the rear surface land 26A, and the front surface land 23B and the rear surface land. A via hole 31 for electrically connecting 26B is formed in the printed circuit board 21, and the via hole 31 is electrically connected to the outer layer pattern 26C through the backside land 26B, and the through hole 30 and the via hole 31 are connected to the inner layer. The pattern 25B is electrically connected.

  According to the printed circuit board 21 having such a structure, when the insertion type electronic component 3 is mounted by the lead-free solder 5, the printed circuit board 21 is not affected by the peeling of the lands 23A and 26A in the through-hole 30 part and the peeling of the wall of the conductor 33. A high-performance printed circuit board can be obtained. That is, when the electrode 4 of the electronic component 3 is inserted into the through hole 30 and fixed to the conductor 30 of the through hole 30 with the lead-free solder 5, the conductor 33 at the corner of the through hole 30 is caused by the thermal stress due to the lead-free solder 5. There is a possibility that the land portions 33 a and 33 b covering the surface of the base material of the conductor 33 may be peeled off from the insulating base material 6. On the other hand, since no insertion type electronic component is mounted in the via hole 31, the lead-free solder 5 is not filled. For this reason, the conductor 34 does not peel from the insulating base 6, and the front surface land 23 </ b> B and the back surface land 26 </ b> B surrounding the via hole 31 do not peel from the insulating base 6.

  Further, since the front-side lands 23A and 23B, the back-side lands 26A and 26B, the outer layer pattern 26C, the conductor 33, and the inner layer pattern 25B are usually joined by the same metal material, there is no possibility of separation due to thermal stress. Furthermore, since the inner layer pattern 25B is sandwiched between the prepregs constituting the insulating base 6, the inner layer pattern 25B is not deformed or disconnected by the thermal stress caused by the lead-free solder 5. Therefore, even if the conductor 33 of the through hole 30 is peeled off from the insulating base 6 or the land portions 33a and 33b of the conductor 33 are peeled off from the front and back surfaces of the insulating base 6, the front side land 23A and the back side It may adversely affect the junction between the land 26A and the conductor 33, the junction between the conductors 33 and 34 and the inner layer pattern 25B, the front-side land 23B, and the junction between the back-side land 26B and the conductor 34. Absent. Therefore, the electrode 4 can be reliably connected to the front surface land 23B and the rear surface land 26B via the conductor 33 of the through hole 30, the inner layer pattern 25B, and the conductor 34 of the via hole 31, respectively. A highly flexible printed circuit board 21 can be provided.

  Further, since it is not necessary to over-resist the front-side land 23A and the back-side land 26A as in Patent Document 1 described above, it is not necessary to increase the printing accuracy of the solder resists 13 and 14, and the ease of drawing the outer layer pattern, It is possible to maintain quality independent of the accuracy of the manufacturing process.

  Further, by incorporating such a printed circuit board 21 into various electronic devices such as a television receiver and a personal computer, a highly reliable electronic device can be provided.

FIG. 2 is a cross-sectional view of a principal part of a printed circuit board showing a second embodiment of the present invention.
The same parts and portions as those in the embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
In the figure, a printed circuit board 51 is constituted by a multilayer printed circuit board having a four-layer structure, whereby an insulating base 6 and first-layer conductive patterns 23A to 23C formed on the surface of the insulating base 6 are shown. The second and third layers of conductive patterns 24A to 24D and 25A to 25D (hereinafter also referred to as inner layer patterns) formed inside the insulating base 6 and the fourth layer formed on the back surface of the insulating base 6 Conductive patterns 26 </ b> A to 26 </ b> D (hereinafter also referred to as outer layer patterns or backside lands), solder resists 13 and 14 formed on the front and back surfaces of the insulating substrate 6, and the like. The printed circuit board 51 has first and second through holes 30A and 30B on which the first and second insertion-type electronic components 3A and 3B are mounted, and one via hole 31.

  The first-layer conductive patterns 23A, 23B, and 23C and the fourth-layer conductive patterns 26A, 26B, and 26D are exposed on the front and back surfaces of the insulating material 6 to form lands on the front and back sides, respectively ( Hereinafter, these conductive patterns are also referred to as lands). The conductive pattern 26 </ b> C forms an outer layer pattern on the back surface side and is covered with the solder resist 14.

  The inner layer pattern 25A electrically connects the first through hole 30A and the second through hole 30B. The inner layer pattern 25B electrically connects the second through hole 30B and the via hole 31. The first through hole 30A electrically connects the land 23A on the front surface side and the land 26A on the back surface side. The second through hole 30B electrically connects the land 23C on the front surface side and the land 26D on the back surface side. The via hole 31 electrically connects the land 23B on the front surface side and the land 26B on the back surface side.

  The electrodes 4 of the first and second insertion-type electronic components 3A and 3B are inserted into the first and second through holes 30A and 30B, respectively, and are lead-free solder 5 to the conductors 33 of the through holes 30A and 30B. Electrically connected.

  Even in the printed circuit board 51 having such a structure, when the insertion type electronic components 3A and 3B are mounted by the lead-free solder 5, the first and second through holes 30A and 30B are not affected by land peeling or wall peeling. A highly reliable printed circuit board can be obtained. That is, when the electrodes 4 of the respective electronic components 3A and 3B are respectively inserted into the first and second through holes 30A and 30B and fixed to the inner walls of the first and second through holes 30A and 30B by the lead-free solder 5. The conductor 33 at the corners of the first and second through holes 30A and 30B is peeled off from the insulating base material 6 by the thermal stress caused by the lead-free solder 5 or the land portion 33a covering the base material surface of the conductor 33. , 33b may be peeled off from the insulating substrate 6. On the other hand, the conductor 33 of the first and second through holes 30A and 30B and the inner layer pattern 25A are formed of the same metal material and joined to each other, and the inner layer pattern 25A is between the prepregs constituting the insulating substrate 6. Therefore, the lead-free solder 5 is not deformed or disconnected by thermal stress. Therefore, even if the conductors 33 of the first and second through holes 30A and 30B are peeled off from the insulating base 6 or the land portions 33a and 33b are peeled off from the front and back surfaces of the insulating base 6, The joint portion between the conductor 33 of the second through holes 30A and 30B and the inner layer pattern 25A will not peel off.

  The conductor 33 of the first through hole 30A and the conductor 34 of the via hole 31 are electrically connected through an inner layer pattern 25B made of the same metal material, and the inner layer pattern 25B is an insulating group. Since it is sandwiched between the prepregs constituting the material 6, it is not deformed or disconnected by thermal stress caused by the lead-free solder 5. Therefore, even if the conductor 33 of the second through hole 30B is peeled off from the insulating base 6 or the land portions 33a and 33b are peeled off from the front and back surfaces of the insulating base 6, the second through hole 30B The joint portion between the conductor 33 and the inner layer pattern 25A is not peeled off due to thermal stress.

FIG. 3 is a cross-sectional view of a principal part of a printed circuit board showing a third embodiment of the present invention.
In the figure, a printed circuit board 70 is composed of a multilayer printed circuit board having a four-layer structure, whereby an insulating base 6 and first-layer conductive patterns 23A to 23D (formed on the surface of the insulating base 6). Hereinafter, also referred to as an outer layer pattern or an outer layer land), second and third conductive patterns 24A to 24E and 25A to 25E (hereinafter also referred to as inner layer patterns) formed inside the insulating base 6, and an insulating group It is composed of fourth-layer conductive patterns 26 </ b> A to 26 </ b> E (hereinafter also referred to as outer layer patterns or outer layer lands) formed on the back surface of the material 6 and solder resists 13, 14 formed on the front and back surfaces of the insulating substrate 6. Yes. The printed circuit board 70 includes first and second through holes 30A and 30B on which the first and second insertion-type electronic components 3A and 3B are mounted, and first and second via holes 31A and 31B. Is formed. The first and second via holes 31A and 31B are provided between the first and second through holes 30A and 30B.

  The conductive patterns 23A to 23D of the first layer form surface-side lands surrounding the first and second through holes 30A and 30B and the first and second via holes 31A and 31B. The inner layer pattern 25B electrically connects the first through hole 30A and the first via hole 31A. The inner layer pattern 25D electrically connects the second through hole 30B and the second via hole 31B.

  The fourth layer conductive patterns 26A, 26B, 26D, and 26E form backside lands that surround the first and second through holes 30A and 30B and the first and second via holes 31A and 31B. The conductive pattern 26C electrically connects the first and second via holes 31A and 31B via the backside lands 26B and 26D.

  The first through hole 30A electrically connects the front side land 23A and the back side land 26A. The second through hole 30B electrically connects the front surface side land 23D and the back surface side land 26E. The first via hole 31A electrically connects the front surface side land 23B and the back surface side land 26B. The second via hole 31B electrically connects the front surface land 23C and the rear surface land 26D.

  The electrodes 4 of the first and second insertion-type electronic components 3A and 3B are inserted into the first and second through holes 30A and 30B, respectively, and are electrically connected to the through holes 30A and 30B by lead-free solder 5. Has been.

  Even in such a structure, when the first insertion type electronic component 3A is soldered to the first through hole 30A by the lead-free solder 5, the first through hole 30A, the first The junction between the via hole 31A and the inner land 25B is not peeled off due to thermal stress.

  Further, when the second insertion type electronic component 3B is soldered to the second through hole 30B with the lead-free solder 5, the joint portion between the second through hole 30B, the second via hole 31B, and the inner layer land 25D is also formed. It does not peel off due to thermal stress.

  For the conductive pattern 26C that electrically connects the first and second via holes 31A and 31B, since the outer layer pattern on the back side is formed, the first and second insertion-type electronic components 3A and 3B are If thermal stress is applied when soldering to the first and second through holes 30A and 30B, the insulating base 6 may be peeled off. However, the first and second via holes 31A and 31B are provided between the first and second through holes 30A and 30B, and the back side conductive pattern 26C is far from the first and second through holes 30A and 30B. Therefore, there is little influence by thermal stress and it does not peel from the insulating base material 6. Therefore, also in the present embodiment, the inner layer patterns 25B and 25D are disconnected due to the lift-off phenomenon, or the inner layer patterns 25B and 25D and the first and second through holes 30A and 30B, and the first and second via holes 31A and 31B. It is possible to prevent the bonded portion from being peeled off, and to provide a highly reliable printed circuit board 70.

  In the embodiment shown in FIG. 2 and FIG. 3, the example in which different electronic components 3A and 3B are respectively mounted on the first and second through holes 30A and 30B is shown. The present invention is not limited to this, and each electrode of one electronic component may be electrically connected to the first and second through holes 30A and 30B.

  Although the present invention has been shown as an example applied to a multilayer substrate having a four-layer structure, the present invention is not limited to this, and any multilayer substrate having N (N ≧ 3) layers or more may be used. it can. Furthermore, the present invention can also be applied to build-up substrates such as IHV and P & SVH.

It is sectional drawing of the principal part which shows the state which mounted the insertion type electronic component which shows 1st Embodiment of the printed circuit board which concerns on this invention. It is sectional drawing of the principal part which shows the state which mounted the insertion type electronic component which shows 2nd Embodiment of the printed circuit board which concerns on this invention. It is sectional drawing of the principal part which shows the state which mounted the insertion type electronic component which shows 3rd Embodiment of the printed circuit board which concerns on this invention. It is sectional drawing of the principal part which shows the prior art example of a printed circuit board. It is sectional drawing of the principal part which shows the other conventional example of a printed circuit board.

Explanation of symbols

3, 3A, 3B ... insertion type electronic component, 4 ... electrode, 5 ... lead-free solder, 6 ... insulating base material, 13,14 ... solder resist, 23A-23D ... first layer conductive pattern, 24A-24E ... second Layer conductive pattern, 25A-25E ... third layer conductive pattern, 26A-26E ... fourth layer conductive pattern, 30 ... through hole, 30A ... first through hole, 30B ... second through hole, 31 ... Via hole, 31A ... first via hole, 31B ... second via hole, 33, 34 ... conductor, 51, 70 ... printed circuit board.

Claims (4)

At least three layers of conductive patterns respectively formed on the front and back surfaces and inside of the insulating substrate;
A solder resist that covers and protects the conductive pattern on the front and back surfaces of the substrate;
At least a first through hole that is formed on the insulating substrate and electrically connects the conductive pattern on the front and back surfaces of the substrate and the conductive pattern on the inner side of the substrate;
An insertion-type electronic component in which an electrode is inserted into the first through hole and electrically connected by lead-free solder;
At least a first via that is electrically connected to the first through-hole via a conductive pattern on the inside of the substrate and that electrically connects the conductive pattern on the surface of the substrate and the conductive pattern on the back of the substrate. The hall,
A printed circuit board comprising: Furthermore, a second through hole formed on the insulating base material for electrically connecting the conductive pattern on the front and back surfaces of the base material and the conductive pattern on the inner side of the base material is provided.
The first and second through holes are electrically connected through a conductive pattern on the inside of the substrate, and an electrode of an insertion type electronic component is inserted into the second through hole to electrically connect with lead-free solder. The printed circuit board according to claim 1, wherein the printed circuit board is connected. Furthermore, a second through hole and a second via hole that are formed on the insulating base material and electrically connect the conductive pattern on the front and back sides of the base material and the conductive pattern on the inner side of the base material,
An electrode of an insertion type electronic component is inserted into the second through hole and electrically connected by lead-free solder;
Electrically connecting the second through hole and the second via hole by a conductive pattern inside the substrate;
The printed circuit board according to claim 1, wherein the first via hole and the second via hole are electrically connected through a conductive pattern on a substrate surface side or a substrate back surface side. An electronic apparatus comprising the printed circuit board according to claim 1.

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