JP2005044990A - Land, manufacturing method, and mounting method for multilayer printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a land for mounting a component in a multilayer printed wiring board that has such a structure to effectively prevent the occurrence of a lift-off phenomenon or a land peeling phenomenon, even if a lead-free solder (non-lead solder) with high melting temperature is used for mounting a component. <P>SOLUTION: The land 20 of a multilayer printed wiring board that is formed on the uppermost surface of a multilayer printed wiring board 10 to mount a component is provided with a via hole 21 and a through hole 22 for inserting a component. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a land portion of a multilayer printed wiring board, a method for manufacturing a multilayer printed wiring board, and a multilayer printed wiring board mounting method, and more particularly, for example, a multilayer printed wiring suitable for use with lead-free solder (lead-free solder). The present invention relates to a method for manufacturing a land portion of a board and a multilayer printed wiring board, and a method for mounting a multilayer printed wiring board using lead-free solder.

  Conventionally, a solder used for soldering a printed wiring board is a tin-lead (Sn—Pb) eutectic solder. Lead in the solder plays a role of lowering the melting point, promoting fluidity, and lowering the surface tension. However, regarding the toxicity of lead, the influence on the human body has been a problem for some time. Moreover, environmental pollution by lead is also a problem. Therefore, in recent years, development and use of lead-free solder (lead-free solder) has been promoted. The component of the lead-free solder is, for example, 93 to 98% by weight of tin, and the rest is composed of silver, copper, and antimony, and there are some that contain a trace amount of bismuth, cadmium, nickel, sulfur, arsenic, and zinc . The melting temperature of lead-free solder is 210 to 230 ° C., which is higher than the melting temperature of tin-lead eutectic solder (about 183 ° C.).

  An example of a conventional land portion provided on a printed wiring board is schematically shown in a partial plan view of FIG. 14A and a partial end view of FIG. For example, the printed wiring board uses a printed board 310 made of a glass epoxy copper-clad laminate in which copper foils 313 are laminated on both sides, and forms a through-hole portion 322 by drilling or through-hole plating of the printed board 310. The wiring layer (not shown) and the land portions 321 (321A, 321B) and the solder mask 330 can be manufactured by etching the plating layer 314 and the copper foil 313. In FIG. 14A, in order to clearly show the land portion 321 and the solder mask 330, a diagonal line from the upper left to the lower right and an oblique line from the upper right to the lower left are given.

  As shown in FIG. 15, when soldering a lead part 340 that is a part mounting part to the through-hole part 322, the lead part 340 is inserted into the through-hole part 322 from the part mounting surface side, and is opposite to the component mounting surface The tip portion of the lead portion 340 exposed on the soldering surface side is soldered to the land portion 321B on the soldering surface side using a solder so that the fillet 351 is formed. The solder enters and fills the gap between the through hole portion 322 and the lead portion 340, and the solder that has passed through the through hole portion 322 forms a fillet on the land portion 321A on the component mounting surface side. Thereby, the part of the lead part 340 on the component mounting surface side is soldered to the land part 321A.

  When such a high melting temperature lead-free solder is used for component mounting, as shown in the schematic partial end view of FIG. 15, the lift-off (solder) in which the fillet 351 of the lead-free solder 350 peels from the land portion 321. Peeling phenomenon occurs, or a land peeling phenomenon occurs in which the land portion 321 peels from the surface of the base material 310A constituting the printed circuit board 310. The state where the lift-off (solder peeling) phenomenon has occurred is schematically shown on the left side of the land portion in FIG. 15, and the state where the land peeling phenomenon has occurred is shown schematically on the right side of the land portion in FIG. In particular, the occurrence of a land peeling phenomenon becomes a fatal defect for a printed wiring board after component mounting.

  The lift-off phenomenon and the land peeling phenomenon do not occur much when the conventional leaded solder is used, and often occur when the lead-free solder is used. Then, regardless of the soldering method, that is, for example, the flow soldering method or the trowel soldering method occurs in the same manner. In addition, no correlation with the soldering method is observed for the sites where these phenomena occur. These phenomena may also occur when parts are removed from the land using a soldering iron. These phenomena are presumed to occur due to thermal shrinkage and solidification shrinkage of lead-free solder.

  Techniques for suppressing or preventing the occurrence of these phenomena are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2001-244614 and 2001-332851. Also, a multilayer printed wiring board in which conductor pads are difficult to peel off at the time of soldering or after soldering is known from JP-A-6-120672.

  In the multilayer printed wiring board disclosed in JP-A-6-120672, a non-through via hole for electrically connecting the outermost layer and the inner layer is provided in a conductor pad provided in the outermost layer of the multilayer printed wiring board. ing.

  Further, the printed circuit board disclosed in Japanese Patent Laid-Open No. 2001-244614 includes a land that is formed around a through hole into which a component lead is inserted and whose surface is covered with a solder fillet when the component is soldered. The land has an opening into which the solder is immersed.

  Furthermore, in the printed wiring board disclosed in Japanese Patent Laid-Open No. 2001-332851, the outer peripheral portion of the land portion provided on the surface of the printed wiring board for mounting components using lead-free solder is printed wiring. It is covered with an extended portion of a solder mask formed on the surface of the plate.

JP-A-6-120672 JP 2001-244614 A JP 2001-332851 A

  However, Japanese Patent Application Laid-Open No. 6-120672 makes no mention of a land portion provided with a through hole portion for component insertion. Further, the printed wiring boards disclosed in Japanese Patent Laid-Open Nos. 2001-244614 and 2001-332851 are effective in preventing the lift-off phenomenon and the land peeling phenomenon, but more reliably suppress these phenomena. There is a strong demand for measures for this.

  Therefore, the object of the present invention is to more effectively prevent and suppress the occurrence of lift-off phenomenon and land peeling phenomenon even when lead-free solder (lead-free solder) having a high melting temperature is used for component mounting. To provide a land portion for component mounting in a multilayer printed wiring board having a structure to obtain, a method for manufacturing a multilayer printed wiring board provided with such a land portion, and a multilayer printed wiring board mounting method using such a multilayer printed wiring board It is in.

  In order to achieve the above object, the land portion of the multilayer printed wiring board of the present invention is a land portion provided on the outermost surface of the multilayer printed wiring board for mounting components, and is a via hole portion and a component. A through-hole portion for insertion is provided.

In order to achieve the above object, a method for producing a multilayer printed wiring board of the present invention comprises:
(A) forming a wiring and a land on the outermost surface of the multilayer printed board;
(B) forming a solder mask on the outermost surface of the multilayer printed circuit board to obtain a multilayer printed wiring board;
Comprising
The step (A) includes a step of forming a via hole portion and a through hole portion for component insertion in the land portion.

In order to achieve the above object, the multilayer printed wiring board mounting method of the present invention comprises:
(A) forming a wiring and a land on the outermost surface of the multilayer printed board;
(B) forming a solder mask on the outermost surface of the multilayer printed circuit board to obtain a multilayer printed wiring board;
(C) The process of mounting the component on the multilayer printed wiring board by fixing the mounting portion of the component to the land portion using lead-free solder,
Comprising
The step (A) includes a step of forming a via hole portion and a through hole portion for component insertion in the land portion.

  In the land portion of the multilayer printed wiring board of the present invention, the manufacturing method of the multilayer printed wiring board, and the multilayer printed wiring board mounting method (hereinafter, these may be collectively referred to simply as the present invention), The portion is a hole in which metal is deposited on the side surface (inner surface) in order to make a through connection of at least the land portions provided on the two outermost surfaces of the multilayer printed wiring board. To insert the lead part of the component). On the other hand, the via hole portion (also referred to as a via hole portion) is not used for component mounting or component insertion, and the land portion and the inner layer (preferably, the outermost layer) provided on the outermost surface of the multilayer printed wiring board. Inner layer portion located immediately below the surface, in other words, in an N-layer multilayer printed wiring board, preferably the inner layer land portion or inner layer wiring formed in the second layer and the (N-1) th layer inner layer) Is a hole in which metal is deposited on the side surface (inner surface), and a blind via hole (a via that is opened only on one outermost surface of the multilayer printed wiring board and does not penetrate the two outermost surfaces) Hall). The through hole portion and the inner layer land portion or the inner layer wiring may be in direct contact with each other or may not be in contact with each other.

  In the present invention, the via hole portion is formed for preventing or suppressing the occurrence of the peeling phenomenon of the land portion, or is formed for preventing or suppressing the occurrence of the lift-off phenomenon of the land portion, or alternatively It is formed to prevent or suppress the occurrence of the land peeling phenomenon and / or the lift-off phenomenon.

  In the land portion of the multilayer printed wiring board of the present invention, the via hole portion may be filled with an extended portion of a solder mask formed on the outermost surface of the multilayer printed wiring board. The hole portion can be configured to be filled with a solder layer covering the land portion. Alternatively, the via hole portion is filled with an extended portion of a solder mask formed on the outermost surface of the multilayer printed wiring board, and a via hole portion different from the via hole portion is filled with a solder layer covering the land portion. It can also be set as the structure currently made. Moreover, in the manufacturing method of the multilayer printed wiring board and the multilayer printed wiring board mounting method of the present invention, in the step (B), the via hole portion can be filled with the extended portion of the solder mask. Alternatively, in the multilayer printed wiring board mounting method of the present invention, the via hole portion can be filled with lead-free solder in the step (C). Alternatively, in the step (B), the via hole portion is filled with the extended portion of the solder mask, and in the step (C), a via hole portion different from the via hole portion is filled with lead-free solder. be able to. Thus, by filling the via hole portion with the extended portion of the solder mask formed on the surface of the multilayer printed wiring board, a so-called anchor effect is exerted by the solder mask, resulting in the occurrence of lift-off phenomenon and land peeling phenomenon, particularly soldering. It is possible to more reliably suppress and prevent the occurrence of land peeling due to manual component removal using a trowel or the like. Alternatively, by filling the via hole portion with the solder layer covering the land portion, the so-called anchor effect by the solder layer acts, so that the occurrence of lift-off phenomenon and land peeling phenomenon can be more reliably suppressed and prevented.

In the configuration in which the via hole portion is filled with the extended portion of the solder mask formed on the outermost surface of the multilayer printed wiring board, the outer peripheral portion of the land portion is covered with the extended portion of the solder mask. In such a configuration, the area of the land portion that is not covered by the extended portion of the solder mask is arbitrary as long as component mounting can be reliably performed. The shape may be determined in consideration of the shape or the like, but the outer peripheral portion of the land portion is preferably covered with an extended portion of the solder mask at least 5 × 10 ⁻⁵ m from the outer edge of the land portion. In some cases, almost all of the land portion may be covered with the extended portion of the solder mask. That is, only the through hole portion may be exposed.

In the present invention, a plurality of (for example, two, three, and four) via hole portions are provided, and each via hole portion may have a circular cross-sectional shape. Here, the cross-sectional shape of the via hole portion refers to the shape of the via hole portion obtained by cutting the multilayer printed wiring board in a virtual plane perpendicular to the thickness direction of the multilayer printed wiring board. The circular shape means that the via hole portion is composed of a circular hole. In this case, the diameter of each via hole portion is 5 × 10 ⁻⁵ m or more, and the shortest distance between the outer peripheral portion of each via hole portion and the outer edge of the land portion is 5 × 10 ⁻⁵ m or more. It is preferable. Also, the area of the figure the outer edge of the land portion is drawn as S _L0, the area of the land portion S _L1, the total area of a figure drawn by the cross-sectional shape of the via-hole portion and S _V, the through hole cross section (multilayer printed when the area of a figure shape of the through hole portion) drawn obtained when cutting the multilayer printed circuit board by a virtual plane perpendicular to the thickness direction of the wiring board was S _T, the relationship of the following formula (1) In this case, S _L1 and S _V are preferably in the relationship of the following formula (2).

S _L0 = S _L1 + S _V + S _T (1)
1 × 10 ⁻³ S _L1 ≦ S _V ≦ 5 × 10 ⁻¹ S _L1 (2)

Alternatively, in the present invention, the cross-sectional shape of the via hole portion may be an annular shape surrounding the through hole portion. The annular via hole portion may be continuous or discontinuous. In this case, the width of the via hole portion is 5 × 10 ⁻⁵ m or more, and the shortest distance between the outer peripheral portion of the via hole portion and the outer edge of the land portion is 5 × 10 ⁻⁵ m or more. preferable. Also, the area of the figure the outer edge of the land portion is drawn as S _L0, the area of the land portion S _L1, the total area of a figure drawn by the cross-sectional shape of the via-hole portion and S _V, the sectional shape of the through hole portion is drawn figures when the area was S _T, but the above relationship expression (1) holds, in this case, the S _L1 and S _V, it is preferable that a relationship of the following equation (3).

5 × 10 ⁻² S _L1 ≦ S _V ≦ 5 × 10 ⁻¹ S _L1 (3)

  In the present invention, the size of the land portion and the diameter of the through-hole portion are essentially arbitrary, and may be determined based on specifications required for the multilayer printed wiring board, dimensions of components to be mounted, and the like. In addition, the planar shape of the land (the shape drawn by the outer edge) is essentially arbitrary, and is circular, elliptical, rectangular, including squares and rectangles, rounded rectangles, polygons, and rounded polygons. It can be. When the planar shape of the land portion is circular, and when the land portion is partially covered by the extended portion of the solder mask, the shape of the outer edge of the land portion and the extended portion of the solder mask that covers the land portion It is preferable that the shape of the edge part is substantially similar. That is, the distance from the outer edge of the land portion to the edge of the extending portion of the solder mask that covers the land portion depends on the position of the outer edge of the land portion, even though it may vary depending on the formation accuracy of the solder mask. Regardless, it is desirable that they are substantially equal. When the planar shape of the land portion is a shape other than a circle, the shape of the edge portion of the extending portion of the solder mask that covers the land portion is preferably a circle. In many cases, one or a plurality of wires extend from the land portion, but the width and thickness of the wires may be determined based on the specifications required for the multilayer printed wiring board.

  The composition and characteristics of lead-free solder (lead-free solder) used in the multilayer printed wiring board mounting method of the present invention are essentially arbitrary. For example, the component is 93 to 98% by weight of tin (Sn). The rest is composed of silver (Ag), copper (Cu), antimony (Sb), bismuth (Bi), cadmium (Cd), nickel (Ni), sulfur (S), arsenic (As), zinc (Zn), cobalt (Co), phosphorus (P), and indium (In) mixed in a trace amount can be used. For example, Sn—Bi, Sn—Bi—Ag—Cu, Sn—Zn, Sn -Zn-In, Sn-Ag-Zn, Sn-Ag, Sn-Ag-Cu, Sn-Ag-Bi-Cu, Sn-Cu can be exemplified. Depending on the component to be mounted, the mounting method, and the soldering method, lead-free cream solder (solder paste) having the above components can be used. The solder used in the land portion of the multilayer printed wiring board or the method for producing the multilayer printed wiring board of the present invention can be a conventional lead-containing solder (leaded solder) in addition to the above lead-free solder. .

  In the present invention, examples of the solder mask (also referred to as a solder resist) include a thermosetting resin film, an ultraviolet curable resin film, a photosensitive resin film, and a so-called dry film. When the solder mask is composed of a thermosetting resin film, heat treatment may be performed after the thermosetting resin is printed on the surface (component mounting surface, soldering surface) of the multilayer printed board by a screen printing method. When the solder mask is composed of an ultraviolet curable resin film, the ultraviolet curable resin may be printed on the surface of the multilayer printed circuit board (component mounting surface, soldering surface) by screen printing and then irradiated with ultraviolet rays. If desired, a heat treatment may be further performed. When the solder mask is composed of a photosensitive resin film, the photosensitive resin layer is placed on the surface of the multilayer printed circuit board (component mounting surface, soldering surface) by screen printing, spraying, curtain coating, spin coating, etc. After the formation, exposure, development, and curing may be performed. When the solder mask is composed of a dry film, the dry film may be laminated on the surface of the multilayer printed board (component mounting surface, soldering surface), and then exposed, developed, and cured. Alternatively, an adhesive layer may be formed on the film. In this case, the film corresponding to the land is drilled by drilling, punching, laser processing, etc., and the film is laminated on the surface of the multilayer printed circuit board (component mounting surface, soldering surface). After that, a cure process may be performed.

  As a multilayer printed wiring board in the present invention, not only a multilayer printed wiring board (so-called rigid multilayer printed wiring board) defined in JIS C 5014, but also a multilayer flexible printed wiring board, a multilayer flex rigid printed wiring board, a multilayer metal core printed wiring A board, a multilayer metal base printed wiring board, a build-up multilayer printed wiring board, and a multilayer ceramic wiring board can be mentioned. A method for laminating these multilayer printed wiring boards may be a conventional method. For example, as a method for producing a rigid multilayer printed wiring board, a mass lamination method, a pin lamination method, and a sequential lamination method can be exemplified. The land, through-hole, via-hole, and wiring are formed by additive methods such as a semi-additive method and a full additive method, even in the so-called subtractive method including the panel plating method and the pattern plating method. Also good. The number of layers in the inner layer portion of the multilayer printed wiring board may be at least one, and may be any number.

  The insulating material constituting each layer of the multilayer printed wiring board (for example, the insulating material or prepreg material constituting the inner layer material or the outer layer material) may be determined based on the specifications of the multilayer printed wiring board to be manufactured. For printed wiring boards, glass cloth and epoxy resin combination, glass cloth and polyimide resin combination, glass cloth and modified polyimide resin combination, glass cloth and epoxy modified polyimide resin combination, glass cloth and bismaleimide / triazine / epoxy Examples of combinations of resins, glass cloth and fluorine resin, glass cloth and PPO (polyphenylene oxide) resin or PPE (polyphenylene ether) resin, polyimide resin film or polyimide resin film, epoxy resin film or epoxy resin film be able to. Moreover, as an insulating material constituting each layer of the multilayer flexible printed wiring board, a combination of a heat-resistant film such as polyimide film and various adhesives (for example, epoxy resin, acrylic resin, polyimide resin), polyimide resin film or polyimide resin A film, an epoxy resin film, or an epoxy resin film can be exemplified. The wiring (circuit) and the land portion are formed by, for example, etching of copper foil (or copper foil plated with copper). The thickness of the copper foil is based on specifications required for the wiring and land portion. What is necessary is just to determine, 70 micrometers thickness, 35 micrometers thickness, 18 micrometers thickness, 12 micrometers thickness, and 9 micrometers thickness can be illustrated. What is necessary is just to determine the thickness of a plating layer based on the specification requested | required of a multilayer printed wiring board.

  As a component in the land portion of the multilayer printed wiring board of the present invention, the manufacturing method of the multilayer printed wiring board, or the multilayer printed wiring board mounting method, carbon film resistors, cylindrical ceramic capacitors, axial lead parts such as diodes, ceramic capacitors, Examples include aluminum electrolytic capacitors, radial lead parts such as transistors, IC parts typified by SIP (Single Inline Package), DIP (Dual Inline Package), and PGA (Pin Grid Array), and various connectors. In addition, these parts may be called a part with a lead part for convenience.

  In the present invention, as a specific method for mounting a component using lead-containing solder (leaded solder) or lead-free solder, a trowel soldering method; various dip soldering methods; a wave type, a double wave Various types of flow soldering methods, such as infrared heating method, hot air heating method, saturated steam heating method, hot plate heating method, flow method, flow dip method, single flow method, electromagnetic method, inert atmosphere method, plasma method, ultrasonic jet method Various reflow soldering methods such as a formula, a laser heating type, a liquid heating type, and an inert atmosphere type can be exemplified.

  In mounting components on a multilayer printed wiring board, a case where a component with a lead is mounted on one side of a multilayer printed wiring board, a case where a surface mounting component and a component with a lead are mounted on one side of a multilayer printed wiring board, multilayer printing There are various cases such as a case where a surface mounting component is mounted on both sides of a wiring board and a component with a lead portion is mounted on one side. In each of these cases, the present invention may be properly used.

  In the present invention, the land portion is provided with a via hole portion and a through hole portion for component insertion. Therefore, when a component is inserted into the through hole portion and, for example, lead-free solder is used to fix the component to the land portion, the via hole portion functions as a kind of anchor, resulting in a separation phenomenon and / or a lift-off phenomenon of the land portion. Can be reliably prevented or suppressed. Therefore, a multilayer printed wiring board having high reliability can be manufactured without any particular increase in manufacturing cost.

  Hereinafter, the present invention will be described based on an embodiment with reference to the drawings. However, the land portion peeling phenomenon and / or the lift-off phenomenon can be more surely realized even though the via hole portion is provided in the land portion. In addition, there is no increase in the manufacturing process of the multilayer printed wiring board.

  Example 1 relates to a land portion of a multilayer printed wiring board according to the present invention, a method for manufacturing a multilayer printed wiring board, and a method for mounting a multilayer printed wiring board. A schematic partial cross-sectional view of the multilayer printed wiring board in Example 1 is shown in FIG. 1, a schematic partial plan view is shown in FIG. 2, and the multilayer printed wiring board in Example 1 in a state where components are mounted is shown in FIG. A schematic partial end view is shown in FIG. In FIG. 2, illustration of a solder layer, lead-free solder, and fillet is omitted.

  The land portion of the multilayer printed wiring board according to the first embodiment is land portions 20A and 20B provided on the outermost surface of the multilayer printed wiring board 10 for mounting components, and the via hole portion 21 and the component insertion portion Through-hole portion 22 is provided. The via hole 21 is formed to prevent or suppress the peeling phenomenon of the land parts 20A and 20B, or to prevent or suppress the lift-off phenomenon of the land parts 20A and 20B. Alternatively, it is formed to prevent or suppress the occurrence of the peeling phenomenon and / or the lift-off phenomenon of the land portions 20A and 20B.

  In the first embodiment, the via hole portion 21 is filled with a solder layer 50A that covers the land portions 20A and 20B (see FIG. 3).

In the first embodiment, the planar shape (the shape drawn by the outer edge) of the land portions 20A and 20B is a circle having a diameter D _L = 2.0 mm. A single wiring 23 extends from the land portions 20A and 20B. In the first embodiment, a plurality of (specifically, four) via hole portions 21 are provided, and the figure drawn by the cross-sectional shape of each via hole portion 21 has a diameter D _V = 5 × 10 ^−. It is a circle of ⁵ m or more (more specifically, the diameter D _V = 0.1 mm). Furthermore, the shortest distance L between the outer peripheral portion of each via hole portion 21 and the outer edges of the land portions 20A and 20B is 5 × 10 ⁻⁵ m or more (more specifically, 0.1 mm). Moreover, the figure which the cross-sectional shape of the through-hole part 22 draws is a circle with a diameter D _T = 1.0 mm. The area of the graphic drawn by the outer edges of the land portions 20A and 20B is S _L0 , the area of the land portions 20A and 20B is S _L1 , and the total area of the graphic drawn by the cross-sectional shape of the via hole portion 21 is S _V. the area of the figure (shape of the through hole 22 obtained when cutting the multilayer printed circuit board by a virtual plane perpendicular to the thickness direction of the multilayer printed wiring board) is drawn when the S _T cross-sectional shape of the section 22, These values are as follows: S _L0 , S _L1 , S _V and S _T satisfy the above formulas (1) and (2).

S _L0 = 1.00πmm ²
S _L1 = 0.74πmm ²
S _V = 0.01πmm ²
S _T = 0.25πmm ²

The multilayer printed wiring board 10 in the illustrated embodiment 1 is a six-layer multilayer printed wiring board, but the number of layers of the multilayer printed wiring board is not limited to six. This multilayer printed wiring board 10 is composed of insulating materials 11 ₁ , 11 ₂ , 11 ₃ and inner layer materials 12 ₁ , 12 ₂ . An insulating material 11 ₂ is disposed between the inner layer material 12 ₁ and the inner layer material 12 ₂ . On one surface of the insulating material 11 ₁ , there is a patterned copper foil 13 ₁ constituting the first layer (outermost layer) wiring (circuit), the land portion 20A of the first embodiment, and the like. On one surface of the inner layer material 12 ₁ , there is a patterned copper foil 13 ₂ constituting the second layer wiring (circuit), the inner layer land portion, etc., and on the other surface of the inner layer material 12 ₁ , the third layer of wiring (circuit), there is patterned copper foil 13 ₃ constituting the inner land portion and the like. Also, on one surface of the inner layer material 12 ₂ , there is a patterned copper foil 13 ₄ constituting a fourth layer wiring (circuit), an inner layer land portion, etc., and on the other surface of the inner layer material 12 _2. the fifth layer of wiring (circuit), the copper foil 13 ₅ patterned constituting the inner land portion and the like are present. On the other surface of the insulating material 11 _3, the wiring-layer 6 (the outermost layer) (circuit), the copper foil 13 ₆ patterned constituting the land portion 20B or the like of the first embodiment exists. The other surface of the insulating material 11 ₁ is in contact with one surface of the inner layer member 12 _1, one surface of the insulating material 11 ₃ is in contact with the other surface of the inner layer member 12 _2. Reference numeral 14 indicates a plating layer, reference numeral 30 indicates a solder mask, reference numeral 50 indicates lead-free solder, and reference numeral 51 indicates a fillet.

  Hereinafter, the manufacturing method of the rigid multilayer printed wiring board of Example 1 and the multilayer printed wiring board mounting method of Example 1 are shown in FIGS. 1, 3, 4 (A) and (B), and ( A description will be given with reference to A) and (B).

[Step-100]
For example, the second layer wiring (circuit) obtained by patterning the copper foil formed on the double-sided copper-clad laminate, the patterned copper foil 13 ₂ constituting the inner layer land portion, etc., and the third layer eye wiring (circuit) is prepared in a known manner an inner plate 12 ₁ having a copper foil 13 ₃ patterned constituting the inner land portion and the like. In addition, the fourth layer wiring (circuit) obtained by patterning the copper foil formed on the double-sided copper-clad laminate, the patterned copper foil 13 ₄ constituting the inner layer land portion, etc., and the fifth layer The inner layer plate 12 ₂ having the patterned copper foil 13 ₅ constituting the wiring (circuit) of the eye, the inner land portion and the like is manufactured by a known method.

[Step-110]
Then, the prepregs 11A ₁ , 11A ₂ , 11A ₃ constituting the insulating materials 11 ₁ , 11 ₂ , 11 ₃ , the inner layer materials 12 ₁ , 12 ₂ , the wiring (circuit) of the first layer (outermost layer), implementation The copper foil 13A ₁ for forming the land portion 20A of Example 1 and the like, the wiring (circuit) of the sixth layer (outermost layer), and the copper foil 13A ₆ for forming the land portion 20B of Example 1 are laminated. (Refer to FIG. 4A), the prepregs 11A ₁ , 11A ₂ , 11A ₃ are cured by heat treatment to obtain a laminated material laminated through the insulating materials 11 ₁ , 11 ₂ , 11 ₃ ( (See FIG. 4B).

[Step-120]
Thereafter, drilling is performed to form through-hole portions and via-hole portions. The holes are formed in the insulating materials 11 ₁ and 11 ₃ by, for example, a method using a laser, a method using a drill, an etching method using an alkaline solution and an acid solution, or a hole forming method using plasma. This can be performed based on the method of providing (see FIG. 5A).

[Step-130]
Next, through-hole plating processing including via-hole plating processing is performed to form the plated layer 14, whereby the via-hole portion 21 and the through-hole portion 22 can be formed (see FIG. 5B).

[Step-140]
Thereafter, the plated copper foils 13A ₁ and 13A ₆ are etched to form the first layer and the sixth layer (outermost layer) wiring (circuit), the land portions 20A and 20B of the first embodiment, and the like. Thus, patterned copper foils 13 ₁ and 13 ₆ can be obtained.

[Step-150]
Thereafter, by forming a solder mask 30 on the outermost surface of the multilayer printed board by a known method, the multilayer printed wiring board 10 shown in FIG. 1 can be obtained. In the first embodiment, the solder mask 30 is not in contact with the outer peripheral portions of the land portions 20A and 20B.

[Step-160]
And the attachment part (lead part 40) of components (not shown) is fixed to the land part 20A of the rigid multilayer printed wiring board 10 manufactured in this way by using lead-free solder 50, and the parts are printed in a multilayer manner. It can be mounted on the wiring board 10 (see FIG. 3). Specifically, when soldering the lead part 40 that is a component attachment part to the through-hole part 22, the lead part 40 is inserted into the through-hole part 22 from the part mounting surface side, and is opposite to the component mounting surface. The tip portion of the lead portion 40 exposed on the soldering surface side is soldered to the land portion 20B on the soldering surface side using the lead-free solder 50 so that the fillet 51 is formed. The lead-free solder 50 enters and fills the gap between the through-hole portion 22 and the lead portion 40, and the lead-free solder 50 that has passed through the through-hole portion 22 fillets 51 on the land portion 20A on the component mounting surface side. Form. Thereby, the part of the lead part 40 on the component mounting surface side is soldered to the land part 20A.

  More specifically, for example, by using a lead-free solder containing Sn-2.5% Ag-1% Bi-0.5% Cu as a component, for example, in a double wave type flow soldering method, Insert the mounting part (lead part) of the part with lead part on which the Sn-10Pb plating layer is formed into the through-hole part 22 from the part mounting surface side, and use the lead-free solder to attach the mounting part (lead part) to the land part. The parts can be mounted on the multilayer printed wiring board by fixing to 20A and 20B.

  At this time, the via hole portion 21 is filled with a solder layer 50A made of lead-free solder covering the land portions 20A and 20B (see FIG. 3). Thus, since the via hole portion 21 functions as a kind of anchor together with the solder layer 50A, it is possible to reliably prevent or suppress the peeling phenomenon and / or the lift-off phenomenon of the land portions 20A and 20B.

  In the multilayer printed wiring board 10 shown in FIG. 1, the inner layer land portion in contact with the bottom portion of the via hole portion 21 is in direct contact with the through hole portion 22, but the inner layer land portion is not limited to such a structure. As shown in a schematic partial cross-sectional view in FIG. 6, in the multilayer printed wiring board 10 </ b> A, the inner layer land portion or the inner layer wiring that contacts the bottom of the via hole portion 21 directly contacts the through hole portion 22. No. Such a structure can also be applied to a multilayer printed wiring board in each embodiment described below.

  In [Step-150], the solder mask 30 may be formed so as to cover the outer peripheral portions of the land portions 20A and 20B. A schematic partial cross-sectional view of such a multilayer printed wiring board 10B is shown in FIG. Such a structure can also be applied to a multilayer printed wiring board in Example 2 described below.

  The second embodiment is a modification of the first embodiment. In Example 1, a plurality of via hole portions are provided, and the cross-sectional shape of each via hole portion is circular. On the other hand, in the multilayer printed wiring board 10C of Example 2, as shown in a schematic partial plan view of FIG. 8, the cross-sectional shape of the via hole portion 21C is an annular shape (more specifically, surrounding the through hole portion 22). Is an annular shape. Except for this point, the structure and manufacturing method of the multilayer printed wiring board 10C of the second embodiment are substantially the same as the structure and manufacturing method of the multilayer printed wiring board 10 described in the first embodiment. The multilayer printed wiring board mounting method 2 is the same as the multilayer printed wiring board mounting method of the first embodiment. Furthermore, the schematic partial cross-sectional view of the multilayer printed wiring board 10C of Example 2 is substantially the same as that shown in FIG. In FIG. 8, illustration of a solder layer, lead-free solder, and a fillet is omitted.

In Example 2, the planar shape (the shape drawn by the outer edge) of the land portions 20A and 20B is a circle having a diameter D _L = 2.0 mm. A single wiring 23 extends from the land portions 20A and 20B. In Example 2, the width W _V of the via hole portion 21C is 5 × 10 ⁻⁵ m or more (specifically, 0.1 mm), and the outer peripheral portion of the via hole portion 21C and the land portions 20A and 20B. The shortest distance L between the outer edges of the two is 5 × 10 ⁻⁵ m or more (more specifically, 0.1 mm). Furthermore, the figure drawn by the cross-sectional shape of the through-hole portion 22 is a circle having a diameter D _T = 1.0 mm. The area of the figure drawn by the outer edges of the land parts 20A and 20B is S _L0 , the area of the land parts 20A and 20B is S _L1 , and the total area of the figure drawn by the cross-sectional shape of the via hole part 21C is S _V , when the area of the figure the cross-sectional shape drawn parts 22 and the S _T, these values are as follows. S _L0 , S _L1 , S _V and S _T satisfy the above formulas (1) and (3).

S _L0 = 1.00πmm ²
S _L1 = 0.58πmm ²
S _V = 0.17πmm ²
S _T = 0.25πmm ²

  In the second embodiment, the via hole portion 21C functions more powerfully as a kind of anchor together with the solder layer 50A than the first embodiment. Therefore, the peeling phenomenon and / or the lift-off phenomenon of the land portions 20A and 20B. It is possible to achieve more reliable prevention or suppression of the occurrence of the above.

  The third embodiment is also a modification of the first embodiment. In the first embodiment, the via hole portion 21 is filled with a solder layer 50A that covers the land portions 20A and 20B. On the other hand, in the multilayer printed wiring board 110 of Example 3, the typical partial sectional view is shown in FIG. 9, the typical partial plan view is shown in FIG. 10, and the multilayer printed wiring board on which the components are mounted is shown. As shown in a schematic partial end view of FIG. 11, the via hole portion 121 is filled with an extending portion of a solder mask 130 formed on the outermost surface of the multilayer printed wiring board 110. Except for this point, the structure of the multilayer printed wiring board 110 of the third embodiment is substantially the same as the structure of the multilayer printed wiring board 10 described in the first embodiment. In FIG. 10, illustration of a solder layer, lead-free solder, and a fillet is omitted.

In the third embodiment, the planar shape (the shape drawn by the outer edge) of the land portions 120A and 120B is a circle having a diameter D _L = 2.0 mm. One wiring 123 extends from the land portions 120A and 120B. In the third embodiment, a plurality (specifically, four) of via holes 121 are provided, and the cross-sectional shape of each via hole 121 is a diameter D _V = 5 × 10 ⁻⁵ m or more. More specifically, it has a circular shape with a diameter D _V = 0.1 mm. Furthermore, the shortest distance L between the outer peripheral portion of each via hole portion 121 and the outer edges of the land portions 120A and 120B is 5 × 10 ⁻⁵ m or more (more specifically, 0.1 mm), and the land portion The outer peripheral portions of 120A and 120B are covered with an extended portion of the solder mask 130 at least 5 × 10 ⁻⁵ m (more specifically, L ′ = 0.3 mm) from the outer edges of the land portions 120A and 120B. Further, the figure drawn by the cross-sectional shape of the through-hole portion 122 is a circle having a diameter D _T = 1.0 mm. The area of the figure drawn by the outer edges of the land parts 120A and 120B is S _L0 , the area of the land parts 120A and 120B is S _L1 , and the total area of the figure drawn by the cross-sectional shape of the via hole part 121 is S _V , the area of the figure (shape of the through hole 122 obtained when cutting the multilayer printed circuit board by a virtual plane perpendicular to the thickness direction of the multilayer printed wiring board) is drawn when the S _T cross-sectional shape of the parts 122, These values are as follows: S _L0 , S _L1 , S _V and S _T satisfy the above formulas (1) and (2).

S _L0 = 1.00πmm ²
S _L1 = 0.74πmm ²
S _V = 0.01πmm ²
S _T = 0.25πmm ²

  The manufacturing method of the rigid multilayer printed wiring board according to the third embodiment covers the outer peripheral portions of the land portions 120A and 120B with the extending portions of the solder mask 130 in the same process as [Step-150] of the first embodiment, and Except for the point that the via hole portion 121 is filled with the extended portion of the solder mask 130, it can be substantially the same as the rigid multilayer printed wiring board described in the first embodiment, and thus detailed description thereof is omitted. Further, the multilayer printed wiring board mounting method of the third embodiment can be substantially the same as the multilayer printed wiring board mounting method of the first embodiment, and thus detailed description thereof is omitted.

  In the third embodiment, the via hole portion 121 is filled with the solder mask 130 covering the outer peripheral portions of the land portions 120A and 120B. Therefore, the via hole portion 121 functions as a kind of anchor together with the solder mask 130. It is possible to reliably prevent or suppress the peeling phenomenon and / or the lift-off phenomenon of the portions 120A and 120B.

  The fourth embodiment is a modification of the third embodiment. In Example 3, a plurality of via hole portions are provided, and the cross-sectional shape of each via hole portion is circular. On the other hand, in the multilayer printed wiring board 110A of Example 4, as shown in a schematic partial plan view of FIG. 12, the cross-sectional shape of the via hole portion 121A is an annular shape (more specifically, surrounding the through hole portion 122). Is an annular shape. Except for this point, the structure and manufacturing method of the multilayer printed wiring board 110A of the fourth embodiment are substantially the same as the structure and manufacturing method of the multilayer printed wiring board 110 described in the third embodiment. A schematic partial cross-sectional view of the multilayer printed wiring board 110A of No. 4 is substantially the same as that shown in FIG. In FIG. 12, illustration of a solder layer, lead-free solder, and fillet is omitted.

In Example 4, the width W _V of the via hole portion 121A is 5 × 10 ⁻⁵ m or more (specifically, 0.1 mm), and the outer peripheral portion of the via hole portion 121A and the outer edges of the land portions 120A and 120B The shortest distance L is 5 × 10 ⁻⁵ m or more (more specifically, 0.1 mm), and the outer peripheral portions of the land portions 120A and 120B are 5 × 10 ⁻ from the outer edges of the land portions 120A and 120B. ⁵ m or more (more specifically, L ′ = 0.3 mm), which is covered with the extending portion of the solder mask 130. Furthermore, the land portion 120A, an area of a figure edge drawn in 120B and S _L0, land portion 120A, an area of 120B S _L1, the total area of the cross section drawing figure via hole portion 121A and S _V, through when the area of the diagram as the profile cross-sectional shape of the hole portion 122 was S _T, these values are as follows. S _L0 , S _L1 , S _V and S _T satisfy the above formulas (1) and (3).

S _L0 = 1.00πmm ²
S _L1 = 0.58πmm ²
S _V = 0.17πmm ²
S _T = 0.25πmm ²

  In the fourth embodiment, the via hole portion 121A functions more powerfully as a kind of anchor together with the solder mask 130 as compared with the third embodiment. Therefore, the peeling phenomenon and / or the lift-off phenomenon of the land portions 120A and 120B are caused. A more reliable generation prevention or suppression can be achieved.

  As mentioned above, although this invention was demonstrated based on the preferable Example, this invention is not limited to these Examples. The configuration, structure, number of layers, manufacturing method and conditions, materials used, component mounting method and conditions, lead-free solder used, components, etc. used for the multilayer printed wiring board described in the examples are examples and should be changed as appropriate. Can do. Even when the conventional leaded solder is used, the land portion may be peeled off from the surface of the base material when the usage condition of the component-mounted printed wiring board is severe. In such a case, it is preferable to apply the land portion of the multilayer printed wiring board of the present invention, the manufacturing method of the multilayer printed wiring board, or the multilayer printed wiring board mounting method even if conventional leaded solder is used. .

  Further, for example, as shown in a schematic partial plan view in FIG. 13, the multilayer printed wiring board having the structure described in Example 1 and the multilayer printed wiring board having the structure described in Example 3 are combined. A multilayer printed wiring board 210 may also be used. That is, the via hole portion 221A is filled with a solder layer covering the land portion 220A, and the via hole portion 221B is filled with an extending portion of the solder mask 230 formed on the outermost surface of the multilayer printed wiring board 210. It can also be configured. In FIG. 13, reference numeral 222 indicates a through hole portion, and reference numeral 223 indicates a wiring. Moreover, in FIG. 13, illustration of a solder layer, lead-free solder, and a fillet is omitted. Furthermore, the multilayer printed wiring board having the structure described in the first embodiment and the multilayer printed wiring board having the structure described in the fourth embodiment can be combined. The multilayer printed wiring board having the structure described above may be combined with the multilayer printed wiring board having the structure described in the third embodiment, or the multilayer printed wiring board having the structure described in the second embodiment. And it can also be set as the multilayer printed wiring board which combined the multilayer printed wiring board of the structure demonstrated in Example 4. FIG.

FIG. 1 is a schematic partial cross-sectional view of a multilayer printed wiring board according to the first embodiment. FIG. 2 is a schematic partial plan view of the multilayer printed wiring board according to the first embodiment. FIG. 3 is a schematic partial end view of the multilayer printed wiring board in Example 1 in a state where components are mounted. 4A and 4B are schematic partial end views of the inner layer material and the like for explaining the method for manufacturing the multilayer printed wiring board of Example 1. FIG. 5A and 5B are schematic partial end views of the inner layer material and the like for explaining the method of manufacturing the multilayer printed wiring board of Example 1 following FIG. 4B. . FIG. 6 is a schematic partial cross-sectional view of a modified example of the multilayer printed wiring board according to the first embodiment. FIG. 7 is a schematic partial cross-sectional view of another modification of the multilayer printed wiring board according to the first embodiment. FIG. 8 is a schematic partial plan view of the multilayer printed wiring board according to the second embodiment. FIG. 9 is a schematic partial cross-sectional view of the multilayer printed wiring board of Example 3. FIG. 10 is a schematic partial plan view of the multilayer printed wiring board according to the third embodiment. FIG. 11 is a schematic partial end view of the multilayer printed wiring board in Example 3 in a state where components are mounted. FIG. 12 is a schematic partial cross-sectional view of the multilayer printed wiring board of Example 4. FIG. 13 is a schematic partial cross-sectional view of a multilayer printed wiring board in which the multilayer printed wiring boards of Example 1 and Example 3 are combined. FIGS. 14A and 14B are a partial plan view and a partial end view schematically showing a land portion in an example of a conventional printed wiring board, respectively. FIG. 15 is a schematic partial end view of a printed wiring board for explaining problems when lead-free solder is used in a conventional printed wiring board.

Explanation of symbols

10, 10A, 10B, 10C, 110, 110A, 210 ... multilayer printed wiring board, 11 ₁ , 11 ₂ , 11 ₃ ... insulating material, 12 ₁ , 12 ₂ ... inner layer material, 13 ₁ , 13 ₂ , 13 ₃ , 13 ₄ , 13 ₅ , 13 ₆ ... Patterned copper foil, 14... Plated layer, 20A, 20B, 120A, 120B, 220A. 121A, 221A, 221B ... via hole part, 22,122,222 ... through hole part, 23,123,223 ... wiring, 30,130,230 ... solder mask, 40 ... lead part 50A ... solder layer, 50 ... lead-free solder, 51 ... fillet

Claims (23)

A land portion provided on the outermost surface of the multilayer printed wiring board for mounting components,
A land portion of a multilayer printed wiring board, wherein a via hole portion and a through hole portion for component insertion are provided. The land portion of the multilayer printed wiring board according to claim 1, wherein the via hole portion is formed for preventing or suppressing the occurrence of a peeling phenomenon and / or a lift-off phenomenon of the land portion. The land portion of the multilayer printed wiring board according to claim 1, wherein the via hole portion is filled with an extended portion of a solder mask formed on the outermost surface of the multilayer printed wiring board. The land portion of the multilayer printed wiring board according to claim 1, wherein the via hole portion is filled with a solder layer covering the land portion. The land portion of the multilayer printed wiring board according to claim 1, wherein a plurality of via hole portions are provided, and a cross-sectional shape of each via hole portion is circular. The diameter of each via hole portion is 5 × 10 ⁻⁵ m or more, and the shortest distance between the outer peripheral portion of each via hole portion and the outer edge of the land portion is 5 × 10 ⁻⁵ m or more. The land part of the multilayer printed wiring board according to claim 5. The land portion of the multilayer printed wiring board according to claim 1, wherein a cross-sectional shape of the via hole portion is an annular shape surrounding the through hole portion. The width of the via hole portion is 5 × 10 ⁻⁵ m or more, and the shortest distance between the outer peripheral portion of the via hole portion and the outer edge of the land portion is 5 × 10 ⁻⁵ m or more. A land portion of the multilayer printed wiring board according to 7. (A) forming a wiring and a land on the outermost surface of the multilayer printed board;
(B) forming a solder mask on the outermost surface of the multilayer printed circuit board to obtain a multilayer printed wiring board;
Comprising
In the step (A), a method for producing a multilayer printed wiring board, comprising the step of forming a via hole portion and a through hole portion for component insertion in the land portion. 10. The method of manufacturing a multilayer printed wiring board according to claim 9, wherein the via hole portion is formed for preventing or suppressing the occurrence of a land peeling phenomenon and / or a lift-off phenomenon. The method for manufacturing a multilayer printed wiring board according to claim 9, wherein in the step (B), the via hole portion is filled with an extended portion of a solder mask. The method for manufacturing a multilayer printed wiring board according to claim 9, wherein a plurality of via hole portions are provided, and a cross-sectional shape of each via hole portion is circular. The diameter of each via hole portion is 5 × 10 ⁻⁵ m or more, and the shortest distance between the outer peripheral portion of each via hole portion and the outer edge of the land portion is 5 × 10 ⁻⁵ m or more. The manufacturing method of the multilayer printed wiring board of Claim 12. The method for manufacturing a multilayer printed wiring board according to claim 9, wherein a cross-sectional shape of the via hole portion is an annular shape surrounding the through hole portion. The width of the via hole portion is 5 × 10 ⁻⁵ m or more, and the shortest distance between the outer peripheral portion of the via hole portion and the outer edge of the land portion is 5 × 10 ⁻⁵ m or more. 14. A method for producing a multilayer printed wiring board according to 14. (A) forming a wiring and a land on the outermost surface of the multilayer printed board;
(B) forming a solder mask on the outermost surface of the multilayer printed circuit board to obtain a multilayer printed wiring board;
(C) The process of mounting the component on the multilayer printed wiring board by fixing the mounting portion of the component to the land portion using lead-free solder,
Comprising
In the step (A), the method for mounting a multilayer printed wiring board includes a step of forming a via hole portion and a through hole portion for component insertion in the land portion. 17. The multilayer printed wiring board mounting method according to claim 16, wherein the via hole portion is formed for preventing or suppressing the occurrence of a land peeling phenomenon and / or a lift-off phenomenon. The multilayer printed wiring board mounting method according to claim 16, wherein in the step (B), the via hole portion is filled with an extended portion of a solder mask. The multilayer printed wiring board mounting method according to claim 16, wherein in the step (C), the via hole portion is filled with lead-free solder. The multilayer printed wiring board mounting method according to claim 16, wherein a plurality of via hole portions are provided, and a cross-sectional shape of each via hole portion is circular. The diameter of each via hole portion is 5 × 10 ⁻⁵ m or more, and the shortest distance between the outer peripheral portion of each via hole portion and the outer edge of the land portion is 5 × 10 ⁻⁵ m or more. The multilayer printed wiring board mounting method according to claim 20. The multilayer printed wiring board mounting method according to claim 16, wherein a cross-sectional shape of the via hole portion is an annular shape surrounding the through hole portion. The width of the via hole portion is 5 × 10 ⁻⁵ m or more, and the shortest distance between the outer peripheral portion of the via hole portion and the outer edge of the land portion is 5 × 10 ⁻⁵ m or more. The multilayer printed wiring board mounting method according to 22.

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