JP2016072320A - Printed wiring board and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high definition and thin double-sided printed wiring board which allows for reliable formation of a solder bump, while preventing such a situation that a solder bump peels off and drops out together with a welding terminal, and also allows for highly accurate conduction test, while preventing warpage even if it is made thinner, and to provide a manufacturing method for enhancing productivity and yield, by preventing warpage in the way of manufacturing.SOLUTION: In a double-sided printed wiring board 51 where a plurality of soldering terminals 53A-C are embedded on one plate side in a substrate 52 so as to be exposed to one plate side, and a plurality of connection terminals 54A-C are embedded on the other plate side in a substrate, the soldering terminal has a surface, exposed to one plate surface side of the substrate, that is flush with the surface of the substrate. The soldering terminal is tapered so that the area of a cross section, in parallel with one plate surface of the substrate, is enlarged toward the inside of the substrate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a printed wiring board used in various electronic / electrical devices, and more particularly to a thin double-layer or multilayer double-sided printed wiring board and a method for manufacturing the same, in which a conductor pattern of a terminal portion is made high definition.

  Conventional printed wiring board manufacturing methods, particularly circuit wiring and the method for forming a conductor layer having a pattern constituting a terminal portion on an insulating base, are subtractive methods, additive methods (full additive method, semi-additive method). It is divided roughly into. Among these, since the semi-additive method can form a fine conductor pattern with higher accuracy than other methods, the semi-additive method has recently been frequently used.

  In the semi-additive method, basically, a thin metal layer (seed layer) such as copper is formed by electroless plating on a substrate made of an insulating material, and then plated with a pattern in which the conductor pattern is inverted. After the resist layer is formed, a conductor layer such as copper is formed on the resist layer non-formed portion by electrolytic plating, and then the plating resist layer is peeled and removed, and further, the seed layer where the conductor layer is not formed by electrolytic plating Is removed by flash etching.

  By the way, recently, the printed wiring board is required to have higher definition than before, and at the same time, further thinner. Specifically, in a printed wiring board having a two-layer structure, the total thickness (excluding solder bumps) is about 0.060 to 0.080 mm, and in a printed wiring board having three or more layers, it varies depending on the number of conductor layers. However, for example, in a four-layer structure, the overall thickness is required to be about 0.130 to 0.150 mm. Such a thin printed wiring board is usually configured so as not to have a so-called core substrate (a high-rigidity thick substrate).

  On the other hand, in a double-sided printed wiring board on which a component such as a semiconductor chip is mounted, a solder welding terminal portion for welding mounting component mounting solder (usually a solder ball) is formed as a terminal portion. It is normal. In the double-sided printed wiring board in which such solder-welded terminal portions are formed, when the above-described thinning is achieved, various problems have occurred in the conventional general structure and manufacturing method.

Here, a typical example of a conventional double-sided printed wiring board that is particularly high definition and thinned (here, an example of a two-layer structure is shown as an example, the situation in the vicinity of the terminal portion is shown in FIG. 19 schematically shows an example of a double-sided printed wiring board having a two-layer structure as an example.
18 shows a cross-sectional structure in the vicinity of the terminal portion, and FIG. 19 shows a situation in plan view of the vicinity of the terminal portion shown in FIG. Here, the printed wiring board 1 shown in FIG. 18 and FIG. 19 basically has a plate shape as a whole. Here, the surface on one side thereof (the upper surface in FIG. 18) A surface on which a component such as a semiconductor chip is mounted, that is, a surface on the component mounting side, is called the first surface 1a of the printed wiring board 1, and the other surface (the lower surface in FIG. 18). Is referred to as the second surface 1b.

  In the printed wiring board 1 shown in FIGS. 18 and 19, the first surface side insulating layer 7 </ b> A is formed on one side (the first surface 1 a side) of the plate-like (layered) base 2 made of an insulating material. In addition, a second surface side insulating layer 7B is formed on the other side (the second surface 1b side) of the base 2. Here, the first surface side insulating layer 7A and the second surface side insulating layer 7B correspond to so-called solder resists, and generally an insulating inorganic material such as an epoxy resin or a phenol resin, for example, Glass cloth, silica, alumina, barium sulfate and the like are blended.

  Further, the mounting component mounting solder (usually solder balls) is welded on the first surface 1a side of the base 2 in a state where it is embedded in the first surface side insulating layer 7A and the surface is exposed to the upper space. Solder welding terminal portions 3A, 3B, 3C are formed. Further, on the second surface 1b side of the base body 2, connection terminal portions 4A, 4B, and 4C for connection to a mother board or the like are embedded in the second surface side insulating layer 7B and the surface is exposed to the lower space. Is formed. And in the example of illustration, among the terminal parts 3B of the solder welding terminal parts 3A, 3B, 3C on the first surface 1a side and the connecting terminal parts 4A, 4B, 4C on the second surface 1b side, The corresponding terminal portion 4B is electrically connected by a through conductive portion (inter-surface conductive portion) 5 that penetrates the base 2 in the thickness direction. The connection terminal portions 4A, 4B, and 4C are generally provided with protective plating layers such as a Ni plating layer 8b and an Au plating layer 8c on the surface of a conductive base material 8a made of copper in order to improve oxidation resistance. It is set as the formed structure.

  Here, the solder-welded terminal portions 3A, 3B, and 3C are formed such that their surfaces are recessed from the surface position of the first surface side insulating layer 7A. That is, the first surface 1a of the printed wiring board 1 has a recess 9A formed at the solder welding terminal portions 3A, 3B, 3C, and the solder welding terminal portions 3A, 3B, The surface of 3C is exposed. In the illustrated example, the connecting terminal portions 4A, 4B, and 4C also have recesses 9B formed on the surfaces thereof that are recessed from the surface position of the second surface side insulating layer 7B. The surfaces of the connection terminal portions 4A, 4B, and 4C are exposed on the bottom surface.

  In order to mount a component such as a semiconductor chip on such a double-sided printed wiring board, as shown in FIGS. 23A and 23B, which will be described later, a part of the solder ball 10 is formed. It is placed on the solder welding terminal portions 3A, 3B, and 3C so as to be inserted into the recess 9, and heated (so-called reflow treatment) to melt the solder balls, and the terminal portions 3A, 3B, and 3C. Solder the solder on the surface. In this state, a part of the solder after the reflow process protrudes from the first surface 1a of the printed wiring board 1, and so-called solder bumps 10A are formed. Therefore, it is possible to join the connection terminal portion of the semiconductor chip to the solder bump 10A.

  A conventional method for manufacturing the conventional double-sided printed wiring board shown in FIGS. 18 and 19 will be described with reference to FIGS.

  As shown in FIG. 20A, a double-sided copper-clad laminate 70 is prepared in advance. This double-sided copper-clad laminate 70 has copper foils 72A and 72B bonded to both sides of a plate-like main insulating support 71 made of insulating resin, and a first inner conductive layer on one surface of the main insulating support 71. 73A is formed by forming the second inner conductive layer 73B on the other surface. First, as shown in FIG. 20B, from the second inner conductive layer 73B (copper foil 72B) side, a predetermined position (between the connecting terminal portion 4B and the solder welding terminal portion 3B in FIG. 18). The via 74 is formed by performing drilling by laser processing at a through-conductive portion (a position where the through-conductive portion is to be conductive). The via 74 extends from the second inner conductive layer 73B (copper foil 72B) through the main insulating support 71 to the inner surface of the first inner conductive layer 73A (a boundary position with the main insulating support 71). Formed to reach.

  Next, as shown in FIG. 20C, a seed layer 75 is formed entirely by electroless copper plating. Here, since the seed layer 75 is also formed on the inner surface of the via 74, the inner surface of the via 74 is electrically connected from the first inner conductive layer 73A to the second inner conductive layer 73B. Will be conducted.

  Further, as shown in FIG. 20D, plating resists 76A and 76B made of a photosensitive resin are laminated on both surfaces, and then exposed and developed into a predetermined pattern as shown in FIG. 20E. At this time, the pattern is set so that the portion of the via 74 is exposed to the second surface side. Then, as shown in FIG. 21A, electrolytic copper plating (pattern plating) is performed to form a first outer conductive layer 77A and a second outer conductive layer 77B having a predetermined pattern. At this time, the portion of the via 74 is exposed to the second surface side. Then, as shown in FIG. 21B, after the resists 76A and 76B are peeled off, as shown in FIG. 21C, formation portions (patterns) of the first outer conductive layer 77A and the second outer conductive layer 77B are formed. The seed layer 75, the copper foil 72A, and the copper foil 72B other than the portion) are removed.

  At this stage, as shown in FIG. 21C, the first inner conductive layer 73A, the seed layer 75, and the first outer conductive layer 77A are integrated on one surface of the main insulating support 71. And a second inner conductive layer 73B, a seed layer 75, and a second outer conductive layer 77B on the other surface of the main insulating support 71. In which the second surface side conductive layer 80B having a predetermined pattern is formed, and the first surface side conductive layer 80A and the second surface side conductive layer 80B are electrically connected in the via 74. It has become. In the following, since the first inner conductive layer 73A, the seed layer 75, and the first outer conductive layer 77A are integrated, they are collectively referred to as the first surface-side conductive layer 80A without distinction. Similarly, the second inner conductive layer 73B, the seed layer 75, and the second outer conductive layer 77B are collectively referred to as the second surface side conductive layer 80B without being distinguished from each other.

  Further, as shown in FIG. 21 (D), solder resists 81A and 81B made of a photosensitive resin are laminated on both surfaces, and as shown in FIG. A state where the surface-side conductive layer 80A and the second surface-side conductive layer 80B are covered with the solder resists 81A and 81B except for the portion that is finally exposed to the outer surface side (the portion that should be the surface of the terminal portion), in other words, The first surface-side conductive layer 80A and the second surface-side conductive layer 80A and the second surface-side conductive layer 80A and the second surface-side conductive layer 80B are exposed in the form in which the central portion (the portion to be the surface of the terminal portion) is exposed to the outer surface. The surface side conductive layer 80B is buried in the solder resists 81A and 81B.

Next, Ni / Au plating is performed on the surface of the conductive layer to be a connection terminal portion mainly for connection to the mother board.
For example, as shown in FIG. 22 (A), first, plating resists 82A and 82B are laminated on both surfaces, and then exposed and developed as shown in FIG. 22 (B). For example, the entire first surface side is plated. The surface of the conductive layer 80B on the second surface side is exposed while being covered with the resist 82A. After that, as shown in FIGS. 22C and 22D, Ni plating and Au plating are performed in this order by, for example, electrolytic plating to form a base Ni plating layer 83 and a surface Au plating layer 84. Thereafter, as shown in FIG. 22E, the plating resists 82A and 82B are peeled off and removed. In this state, the portion in the recess 9A on the surface of each first surface side conductive layer 80A constitutes the welding terminal portions 3A, 3B, 3C on the first surface 1a side, and each second surface side conductive layer 80B. The portion in the recess 9B on the surface of the surface is in a state of constituting the connection terminal portions 4A, 4B, 4C on the second surface 1b side. Therefore, the double-sided printed wiring board 1 as shown in FIGS. 18 and 19 is manufactured.

Here, in the stage before the printed wiring board 1 manufactured as described above is shipped from the manufacturing factory, the solder balls are actually welded to the surfaces of the welding terminal portions 3A, 3B, 3C, In many cases, so-called solder bumps are formed. Even when the solder bumps are not formed, the solder bumps are usually formed at the factory where the products are shipped.
The process of welding the solder balls as described above will be described with reference to FIG.

  As shown in FIG. 23A, the solder balls 10 are mounted (mounted) on the surfaces of the solder welding terminal portions 3A, 3B, and 3C, respectively. At this time, when the lower part of the solder ball 10 is inserted into the recess 9A, the lower part of the solder ball 10 comes into contact with the surfaces of the solder welding terminal portions 3A, 3B, and 3C. Thereafter, flux is applied to the substrate surface (including solder) and heated to a temperature equal to or higher than the melting point of the solder to melt the solder on the surfaces of the solder welding terminal portions 3A, 3B, and 3C. That is, so-called reflow processing is performed. As a result, the solder is welded to the surfaces of the welding terminal portions 3A, 3B and 3C, and solder bumps 10A protruding from the first surface 1a of the printed wiring board 1 are formed as shown in FIG. The

The conventional high-definition and thin double-sided printed wiring board as described above has the following problems.
That is, as shown in FIG. 23, when the solder balls 10 are mounted on the solder welding terminal portions 3A, 3B, and 3C and are welded by the reflow process, the diameter of the solder balls 10 is not strictly constant, It is normal that there is a variation. And as shown to FIG. 24 (A), when the diameter of the solder ball 10 is appropriate with respect to the internal diameter of 9 A of recessed parts which the solder welding terminal part 3A, 3B, 3C is exposed to the bottom face In the mounting, the lower part of the solder ball 10 is surely in contact with the surface of the solder welding terminal portions 3A, 3B, 3C, and the upper part of the solder bump 10A after the reflow treatment is the surface of the first surface side insulating layer 7A. It is in a state of reliably projecting from the position (position of the first surface 1a), so that it is possible to easily mount the component using solder bumps.

  However, as shown in FIG. 24B, when the diameter of the solder ball 10 is too small with respect to the inner diameter of the concave portion 9A, the solder bump 10A after the reflow treatment is formed on the first surface side insulating layer 7A. It will be in the state which does not protrude from the surface position (position of the 1st surface 1a), Therefore, it becomes difficult to mount components reliably and stably using a solder bump.

  On the other hand, as shown in FIG. 24C, when the diameter of the solder ball 10 is too large with respect to the inner diameter of the recess 9A, the solder ball 10 is caught on the shoulder 9a of the recess 9A during mounting. In other words, the bottom surface of the recess 9A, that is, the solder welding terminal portions 3A, 3B, and 3C are not in contact with each other. In this case, even if the solder ball 10 falls off before the start of the subsequent reflow treatment, or even if it does not fall off before the start of the reflow treatment, the solder ball 10 is connected to the solder welding terminal portions 3A, 3B, The reflow process is performed in a state of not contacting the surface of 3C, so that the solder bump 10A is not reliably welded to the surfaces of the solder welding terminal portions 3A, 3B, and 3C. In that case, the solder bump 10A may fall off during product handling or transportation, and even if it does not fall off, sufficient electrical continuity between the soldering terminal portions 3A, 3B, and 3C is not achieved. It will be.

  Furthermore, in the conventional double-sided printed wiring board 1 as described above, the solder bump 10A after the reflow treatment is securely welded to the surface of the solder welding terminal portions 3A, 3B, 3C, and the upper portion of the solder bump 10A. Even when the surface of the first surface side insulating layer 7A is reliably protruding from the surface position (position of the first surface 1a), such as vibration or impact before the component mounting or after the component mounting. As a result, the solder bump 10A may be peeled off or dropped together with the solder welding terminal portions 3A, 3B, and 3C on the lower side. That is, since the first surface side insulating layer (solder resist) 7A around the recess 9A is generally soft, the force for holding the solder-welded terminal portions 3A, 3B, and 3C is not necessarily large, and therefore, large impact and vibration Is added, there is a concern that the solder welding terminal portions 3A, 3B, 3C are separated from the main insulating support 71 and peeled off or dropped together with the solder bumps 10A.

  On the other hand, in the printed wiring board manufacturing process, before the solder ball mounting and reflow processing, the tip of the probe pin for inspection is placed on the terminal to check the electrical continuity of the wiring in the wiring board. It is made to contact | abut and to send an electric current from a terminal part inside. However, the conventional double-sided printed wiring board as described above has the following problems even in the continuity test.

  That is, in the continuity test, the probe pin for inspection is brought close to the printed wiring board, and its tip is brought into contact with the surface of the terminal portion. At this time, in order to avoid deformation and damage of the terminal portion, the probe pin is generally brought into contact with the terminal portion with a relatively small contact pressure. However, at the time of actual inspection, the probe pin is not always along the direction perpendicular to the printed wiring board and often approaches the printed wiring board in a slightly inclined state. In that case, as shown in FIG. 25, the inclined probe pin P collides with the shoulder 9a of the recess 9A, and the tip of the probe pin P is the surface of the solder-welded terminal portions 3A, 3B, 3C. The continuity test may be performed without touching. In that case, it is determined that the circuit wiring is accidentally disconnected. Therefore, there is a problem that the reliability of the continuity test is lacking.

  Furthermore, conventional high-definition and thin double-sided printed wiring boards, especially coreless type double-sided printed wiring boards, are extremely thin as a whole, generally about 0.2 to 0.09 mm, and in some cases 0.085 mm or less. Therefore, its rigidity is low, and therefore, it is easy to warp, bend, and undulate as a whole. In that case, there is a problem that troubles are likely to occur during shipment, transportation, or mounting of mounted components.

On the other hand, the conventional high-definition and thin double-sided printed wiring board manufacturing method shown in FIGS. 20 to 22 has the following problems.
In other words, when manufacturing printed wiring boards with high-definition and thin double-sided printed wiring boards, the intermediate products at each stage in the middle of the manufacturing process are thin. The rigidity as a whole must be low. For this reason, it is likely to bend, warp or undulate during handling or transport during the manufacturing process. In that case, it is easy to interfere with smooth handling and conveyance of the intermediate product. Therefore, it is necessary to temporarily stop the operation due to troubles during manufacture, and productivity tends to be lowered. As a result, the yield of non-defective products also decreases.

  A double-sided printed wiring board in which a concave portion is formed in the location of the solder welding terminal portion on the first surface of the printed wiring board, and the surface of the solder welding terminal portion is exposed on the bottom surface of the concave portion, and Patent Document 1 is presented as a prior art document showing the manufacturing method. In this patent document 1, as an example, a double-sided printed wiring board having a coreless type multilayer structure without a core substrate is shown, and there is a problem similar to the above in the case of such a multilayer structure.

JP 2012-15158 A

The present invention has been made against the background described above, and as a double-sided printed wiring board with high definition and thinness, an appropriate solder bump can be reliably formed, and the solder bump is soldered after the solder bump is formed. It is possible to prevent the occurrence of a situation where the welding terminal part is peeled off or dropped out, and the continuity test can be performed with high accuracy, and even if it is made thinner, it is warped, bent, It is an object to provide a printed wiring board that does not wave.
Furthermore, as a manufacturing method for double-sided printed wiring boards with high definition and thinness, intermediate products are prevented from warping, bending, and undulation in the middle of the manufacturing process. It is also an object of the present invention to provide a manufacturing method that can improve the yield of non-defective products.

The printed wiring board according to the basic aspect (first aspect) of the present invention is:
A plurality of soldering terminal portions are embedded on the side of one plate surface of the base made of an insulating material as a whole so as to be exposed on the one plate surface, and the other plate surface of the base is formed. In the double-sided printed wiring board in which a plurality of connection terminals are embedded on the side,
In the solder welding terminal portion, the surface exposed on the one plate surface side of the base body is substantially flush with the surface of the base body,
In addition, the solder welding terminal portion has a side surface of a portion embedded in the base so that an area of a cross section parallel to the one plate surface of the base increases toward the other plate surface of the base. Is formed in a tapered shape.

  According to such a printed wiring board of the basic aspect of the present invention, the front surface of the solder-welded terminal portion is substantially flush with the plate surface (first surface). When solder balls are mounted (mounted) on the solder welding terminals for solder bump formation and reflow processing is performed, even if the solder ball diameter varies, the solder balls must be The solder bump can be brought into contact with the solder-welded terminal portion, and therefore, the solder bump after the reflow treatment can be surely formed on the solder-welded terminal portion. It will be in the state which protruded from said one board surface (1st surface).

  Further, as described above, the solder-welded terminal portion has a surface on the front side that is substantially flush with the one plate surface (first surface), so that it is conductive before the solder ball is welded. In performing the test, the probe pin of the continuity test apparatus can be reliably brought into contact with the terminal portion, and therefore the reliability and reliability of the continuity test can be improved.

  Further, since the side surface of the solder welding terminal portion is tapered so that the cross-sectional area parallel to the one plate surface increases toward the inside of the base, It is in a state where it is held in the surrounding insulating material layer (generally a solder resist) on the side, so that even if impact or vibration is applied, the solder bump after reflow treatment peels off together with the solder welding terminal part Can be effectively prevented from falling off.

The printed wiring board according to the second aspect of the present invention is the printed wiring board according to the first aspect,
A double-sided printed wiring board having a conductor pattern formed on both sides of the substrate,
A plurality of portions of the conductor pattern on one side of the base are the solder welding terminal portions,
A plurality of portions of the conductor pattern on the surface on the other side of the base are the connection terminal portions,
The base is a plate-like main support, a first surface-side insulating layer formed on one surface side of the main support, and a second surface formed on the other surface side of the main support. A side insulation layer,
The solder welding terminal portion is embedded in the first surface side insulating layer, and the connection terminal portion is embedded in the second surface side insulating layer.

Moreover, the printed wiring board according to the third aspect of the present invention is the printed wiring board according to the second aspect,
Each of the first surface side insulating layer and the second surface side insulating layer has a structure in which 60 to 85 wt% of an inorganic substance is blended in an insulating resin, and the amount of inorganic material blended in one insulating layer and the other insulating layer is The difference is in the range of 0 to 5 wt%.

  In such a printed wiring board of the third aspect, the rigidity is increased as a whole by blending the first surface side insulating layer and the second surface side insulating layer with an inorganic substance at a high concentration of 60 to 85 wt%. In addition, since the difference between the amount of the inorganic substance in one insulating layer and the other insulating layer is small (it may be zero), it is possible to effectively prevent warping, bending, and undulation. .

The printed wiring board according to the fourth aspect of the present invention is the printed wiring board according to any one of the first to third aspects,
Any one or more solder welding terminal portions of the solder welding terminal portions and any one or more connection terminal portions of the connection terminal portions penetrate the base in the thickness direction. It is electrically connected by a through conductive portion (inter-surface conductive portion).

Furthermore, the printed wiring board according to the fifth aspect of the present invention is the printed wiring board according to the fourth aspect,
The penetrating conductive portion (inter-surface conductive portion) has a cross-sectional area parallel to the one plate surface of the base so as to expand from the first surface side conductor layer side toward the second surface side conductor layer side. Further, the side surface is formed in a taper shape.

  In the printed wiring board according to the fifth aspect, since the through conductive portion (inter-surface conductive portion) is also formed in a tapered shape, the through conductive portion (inter-surface conductive portion) also bites into the surrounding insulating layer. Since the soldering terminal part is usually integrated with the through-conductive part (inter-surface conductive part), the solder bump after reflow treatment on the soldering terminal part is soldered by impact or vibration. It is possible to more surely and effectively prevent peeling and dropping together with the welding terminal portion and the through conductive portion (inter-surface conductive portion).

  Furthermore, the printed wiring board according to the sixth aspect of the present invention is the first surface-side insulation formed on the one surface side of the main support in the printed wiring board according to any one of the second to fifth aspects. One or more inner conductor layers are formed in a predetermined pattern in parallel with the plate surface in the main support between the layer and the second surface side insulating layer formed on the other surface side of the main support As a whole, the number of conductor layers is a multilayer structure of 3 or more.

  Each of the seventh to eleventh aspects described below is an aspect of the invention of the method for manufacturing a printed wiring board.

That is, the method for manufacturing a printed wiring board according to the seventh aspect of the present invention includes:
A manufacturing method for manufacturing the printed wiring board of the second aspect,
A first insulating resin layer forming step of forming a first insulating resin layer to be a first surface side insulating layer in a printed wiring board of a final product on one side of a temporary supporting metal plate prepared in advance;
A first opening forming step of forming a first opening by laser processing at a position where the solder welding terminal portion is to be formed in the first insulating resin layer;
The first insulating resin layer is subjected to pattern plating with a conductive metal, and includes a portion to be the solder welding terminal portion, and the portion to be the solder welding terminal portion is embedded in the first opening. A first surface side conductor layer forming step of forming a first surface side conductor layer;
A third insulating resin layer forming step for forming a third insulating resin layer to be the main support so as to cover the surface of the first insulating resin layer and the surface of the first surface-side conductor layer;
A second surface side conductor layer forming step of performing pattern plating with a conductive metal on the third insulating resin layer to form a second surface side conductor layer including a portion to be the terminal portion for connection;
A second insulating resin layer forming step of forming a second insulating resin layer to be the second surface side insulating layer so as to cover the surface of the third insulating resin layer and the second surface side conductor layer;
A second opening forming step of forming a second opening in the second insulating resin layer so that a surface of a portion to be the connection terminal portion in the second surface side conductor layer is exposed;
A temporary support metal plate removing step of removing the temporary support metal plate covering the surfaces of the first insulating resin layer and the first surface side conductor layer;
Have
In the first opening forming step, the first opening is passed through the first insulating resin layer in the thickness direction, and the opening cross-sectional area perpendicular to the thickness direction of the insulating resin from the opening end toward the inside Forming a tapered shape that is reduced,
It is characterized by this.

  In such a printed wiring board manufacturing method of the seventh aspect, from the initial stage of the manufacturing process, for example, a temporary support metal plate such as a copper plate is used, and each layer is laminated based on the temporary support metal plate, or The process of each process is performed in the state supported by the temporary support metal plate until it is removed and the temporary support metal plate is removed in the final stage. Therefore, from the initial stage to the final stage of the manufacturing process, the strength and rigidity of the intermediate product are compensated by the temporary support metal plate. Therefore, it is possible to prevent intermediate products from warping, bending, undulation, etc., between processes due to insufficient strength and rigidity. Therefore, deformation of the intermediate products hinders transportation, transfer, and handling between processes. It is possible to prevent the occurrence of such a situation.

Moreover, the manufacturing method of the printed wiring board by the 8th aspect of this invention WHEREIN: In the manufacturing method of the printed wiring board of the said 7th aspect,
further,
Between the third insulating resin layer forming step and the second surface side conductor layer forming step,
In the third insulating resin layer, a third insulation is provided at a place to be an inter-surface conduction portion between any solder welding terminal portion on the printed wiring board of the product and the corresponding connection terminal portion. Including a third opening forming step of forming a third opening penetrating the resin layer in the thickness direction;
In the second surface side conductor layer formation, pattern plating is performed so that a conductor metal is embedded in the opening.
It is characterized by this.

A method for manufacturing a printed wiring board according to the ninth aspect of the present invention is the method for manufacturing a printed wiring board according to the eighth aspect,
In the third opening forming step, the opening area in the cross section parallel to the one plate surface of the base is changed from the first surface side conductor layer side to the second surface side by laser processing. It is formed in a taper shape so as to expand toward the conductor layer side.
It is characterized by this.

A method for manufacturing a printed wiring board according to a tenth aspect of the present invention is the method for manufacturing a printed wiring board according to any one of the seventh to ninth aspects.
further,
Between the second opening forming step and the temporary support metal plate removing step,
Including a terminal plating step of performing precious metal plating for protection on the surface of the portion to be the terminal portion for connection in the second surface side conductor layer,
It is characterized by this.

A printed wiring board manufacturing method according to an eleventh aspect of the present invention is the printed wiring board manufacturing method according to any of the seventh to tenth aspects,
As the first surface side insulating layer and the second surface side insulating layer, a composite material in which 60 to 85 wt% of an inorganic substance is mixed with an insulating resin is used, and the composite material of one insulating layer and the other insulating layer are used. The difference in the amount of inorganic substance in the composite material is in the range of 0 to 5 wt%.
It is characterized by this.

In the printed wiring board of the present invention, an appropriate solder bump can be reliably formed as a high-definition and thin double-sided printed wiring board, and the solder bumps are formed together with the solder-welded terminal portions after the solder bumps are formed. It is possible to prevent the occurrence of a situation where peeling or dropping occurs, and the continuity test can be performed with high accuracy. Further, even if the thickness is further reduced, warping, bending, and undulation will occur. This can be surely prevented.
Furthermore, as a manufacturing method for double-sided printed wiring boards with high definition and thinness, intermediate products are prevented from warping, bending, and undulation in the middle of the manufacturing process. And the yield of non-defective products can be increased.

It is a typical longitudinal cross-sectional view which shows the fundamental cross-section structure of the terminal part vicinity of the printed wiring board of the 1st Embodiment of this invention. It is the typical top view which planarly viewed the terminal part vicinity of the printed wiring board of 1st Embodiment shown by FIG. It is a typical longitudinal cross-sectional view which shows the fundamental cross-section structure of the terminal part vicinity of the printed wiring board of the 2nd Embodiment of this invention. It is the typical top view which planarly viewed the terminal part vicinity of the printed wiring board of 2nd Embodiment shown by FIG. FIG. 2 is a schematic illustration showing step by step and in principle the steps of an initial stage of an example of the method for manufacturing a printed wiring board according to the first embodiment of the present invention shown in FIG. FIG. 6 is a schematic diagram illustrating steps following FIG. 5 in a stepwise manner. FIG. 7 is a schematic diagram illustrating steps following FIG. 6 in a stepwise manner. FIG. 8 is a schematic diagram showing steps following the step in FIG. 7. FIG. 9 is a schematic illustration showing steps following the step in FIG. 8. FIG. 10 is a schematic illustration showing steps following the step in FIG. 9. It is a schematic diagram which shows the process following FIG. 10 in steps. FIG. 12 is a schematic diagram illustrating a step of welding a solder ball to a solder welding terminal portion in a stepwise manner following FIG. 11 for the printed wiring board according to the first embodiment of the present invention. It is a typical longitudinal cross-sectional view which shows the fundamental cross-section structure of the terminal part vicinity of embodiment applied to the multilayer printed wiring board as a printed wiring board of the 3rd Embodiment of this invention. It is a schematic diagram which shows the process of the intermediate | middle step of an example of the manufacturing method of the multilayer printed wiring board of 3rd Embodiment in steps and in principle. FIG. 15 is a schematic diagram showing steps following the step in FIG. 14. FIG. 16 is a schematic diagram illustrating steps following FIG. 15 in a stepwise manner. FIG. 17 is a schematic view showing a step of welding a solder ball to a solder welding terminal portion in a stepwise manner following FIG. 16 for a printed wiring board according to a third embodiment of the present invention. It is a typical longitudinal cross-sectional view which shows the fundamental cross-section structure of the terminal part vicinity of an example of the conventional double-sided printed wiring board. It is the typical top view which planarly viewed the terminal part vicinity of the conventional double-sided printed wiring board shown by FIG. FIG. 19 is a schematic diagram showing step by step and in principle the steps of the initial stage of an example of the method for manufacturing the conventional double-sided printed wiring board shown in FIG. 18. FIG. 21 is a schematic diagram illustrating steps following FIG. 20 in a stepwise manner. FIG. 22 is a schematic diagram illustrating steps following FIG. 21 in a stepwise manner. FIG. 23 is a schematic diagram showing step by step a step of welding solder balls to solder welding terminal portions of a conventional double-sided printed wiring board manufactured by the steps of FIGS. 20 to 22. It is a schematic diagram for demonstrating the problem at the time of welding a solder ball to the soldering terminal part of the conventional double-sided printed wiring board shown in FIG. 18, FIG. It is a schematic diagram for demonstrating the problem in the case of performing a wiring continuity inspection about the conventional double-sided printed wiring board shown in FIG. 18, FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, FIG. 1 shows in principle the cross-sectional structure of the main part (near the terminal part) of the printed wiring board of the first embodiment in which the present invention is applied to a two-layer printed wiring board. FIG. 1 shows a vicinity of a terminal portion of a printed wiring board according to a first embodiment. Here, an embodiment of a two-layer printed wiring board is shown as a simplified principle example.

The printed wiring board 51 according to the first embodiment shown in FIGS. 1 and 2 basically has a plate shape as a whole, and here, the plate surface on one side thereof (the upper side in FIG. 1). Surface) is referred to as a first surface 51a, and the plate surface on the other side (the lower surface in FIG. 1) is referred to as a second surface 51b.
This printed wiring board 51 is solder for welding mounting component mounting solder (usually solder balls) to one side (first surface 51a side) of a plate-like (layered) base 52 made of an insulating material. The welding terminal portions 53A, 53B, and 53C are formed, and the connection terminal portions 54A, 54B, and 54C for connecting to the motherboard are formed on the other side (the second surface 51b side) of the base 52. In the illustrated example, of the terminal portions 53B of the welding terminal portions 53A, 53B, 53C on the first surface 51a side and the connection terminal portions 54A, 54B, 54C of the second surface 51b side, The connecting terminal portion 54B at a position corresponding to the welding terminal portion 53B is electrically connected by a through conductive portion (inter-surface conductive portion) 55 that penetrates the base 52 in the thickness direction.

  The base body 52 made of an insulating material includes a plate-like main support 56 made of a relatively hard insulating resin or the like constituting a central portion in the thickness direction, and the first side (the first surface 51a side) in the thickness direction. The one-surface-side insulating layer 57A and the second-surface-side insulating layer 57B on the other side in the thickness direction (the second surface 51b side) are stacked. Accordingly, the surface of the substrate 52 on the first surface 51a side corresponds to the surface of the first surface side insulating layer 57A, and the surface of the substrate 52 on the second surface 51b side corresponds to the surface of the second surface side insulating layer 57B. To do.

  The solder welding terminal portions 53A, 53B, and 53C are embedded in the first surface side insulating layer 57A, and the surface thereof is substantially flush with the first surface 51a, and therefore substantially the surface of the first surface side insulating layer 57A. It is formed to be flush with each other. Here, the term “substantially flush” means that, in practice, a protrusion or a depression within a range of about ± 0.005 mm is allowed with respect to the surface position of the first surface side insulating layer 57A. . Furthermore, the solder welding terminal portions 53A, 53B, 53C have side surfaces 53a (boundary surfaces with the first surface side insulating layer 57A) 53a tapered. That is, the cross-sectional area of the surface parallel to the first surface 51a is directed inward in the thickness direction (toward the main support 56) so as to have a taper in a direction in which the diameter increases inward from the surface. E) It is made to have a taper that expands. The inner end portions 53b of the solder welding terminal portions 53A, 53B, and 53C are embedded in the main support 56 with a diameter larger than the maximum diameter of the tapered portion. The inner end portions 53b of the welding terminal portions 53A, 53B, 53C thus embedded in the main support 56 are portions that form a circuit pattern on the first surface 51a side in the printed wiring board 51 (first not shown). Usually, it is continuous with the surface-side conductive pattern portion).

  On the other hand, the connecting terminal portions 54A, 54B, 54C are embedded in the second surface side insulating layer 57B, and the surface thereof is exposed in the second opening 57Ba formed in the second surface side insulating layer 57B. Has been. And on the surface 54a of the connection terminal portions 54A, 54B, 54C in the second opening 57Ba, there are a Ni plating layer 58B and an Au plating layer 58A as protective plating layers for preventing surface oxidation and corrosion. Is formed. The inner base end portion 54b of the connection terminal portions 54A, 54B, and 54C has a larger diameter than the exposed portion in the first opening 57Ba. The inner base end portion 54b is usually continuous with a portion (second surface side conductive pattern portion 90; see FIG. 2) that forms a circuit pattern on the second surface 51b side in the printed wiring board 51.

  Here, the angle θ formed by the side surface (the boundary surface with the first surface side insulating layer 57A) 53a of the solder welding terminal portions 53A, 53B, 53C with respect to the first surface 51a, that is, the first surface side insulating layer 57A. The angle θ formed with respect to the surface (hereinafter, this angle θ is referred to as a taper angle) is preferably within a range of 30 ° to 80 °, and more preferably within a range of 40 ° to 60 °. The reason for setting a desirable range of the taper angle θ of the side surface 53a of the solder welding terminal portions 53A, 53B, and 53C will be described later.

Moreover, the main support body 56 should just be comprised with the material similar to the insulating material conventionally used as an insulation base material of a thin double-sided printed wiring board, The material is not specifically limited, Generally, an epoxy resin It is preferable to use an insulating resin such as a phenol resin.
The first surface side insulating layer 57A and the second surface side insulating layer 57B are layers corresponding to so-called solder resists as described in the manufacturing method described later, and have conventionally been used as solder resists in thin double-sided printed wiring boards. Although the curable resin used may be used, in the case of the printed wiring board of the present invention, a composite material of the curable resin and the inorganic material is used, and the content of the inorganic material in the composite material is 60 wt% or more, It is desirable to set it to 85 wt% or less. Further, the difference between the inorganic content contained in the composite material of the first surface side insulating layer 57A and the inorganic content contained in the composite material of the second surface side insulating layer 57B is in the range of 0 to 5 wt%. It is desirable that The reason for setting the desirable range of the content of the inorganic substance in these composite materials and the ratio of the first surface side and the second surface side thereof will be described later.

  The curable resin of the composite material of the first surface side insulating layer 57A and the second surface side insulating layer 57B may be either thermosetting or ultraviolet curable. For example, as the thermosetting resin, epoxy resin, phenol Resins and the like, and as an ultraviolet curable resin, resins based on epoxy resins can be used.

  The inorganic material contained in the composite material of the first surface side insulating layer 57A and the second surface side insulating layer 57B is not particularly limited as long as it is a material that can be expected to improve strength by being combined with the resin. However, usually one or more of glass cloth, silica, alumina, barium sulfate, titanium oxide, aluminum hydroxide, magnesium hydroxide and the like may be used. The inorganic form is cloth, fiber Any of powder particles may be used.

  The curable resin of the composite material of the first surface side insulating layer 57A and the curable resin of the composite material of the second surface side insulating layer 57B are desirably the same type of resin from the viewpoint of cost. It doesn't have to be the same. In addition, the inorganic material of the composite material of the first surface side insulating layer 57A and the inorganic material of the composite material of the second surface side insulating layer 57B are preferably the same type of materials from the viewpoint of cost, but they need to be the same type. There is no. Further, the inorganic content in the composite material is not necessarily the same between the first surface side insulating layer 57A and the second surface side insulating layer 57B, but as described above, the difference is 0 to 5 wt%. It is desirable to be within the range.

FIG. 12 schematically shows a situation in which the solder ball 10 is welded to the solder welding terminal portions 53A, 53B, 53C using the printed wiring board 51 of the embodiment shown in FIGS. 1 and 2 as described above.
As shown in FIG. 12A, the solder balls 10 are mounted (mounted) on the surfaces of the solder welding terminal portions 53A, 53B, and 53C, respectively. Thereafter, the solder is heated to a temperature equal to or higher than the melting point of the solder to melt the solder on the surfaces of the solder welding terminal portions 53A, 53B, and 53C. That is, so-called reflow processing is performed. As a result, the solder is welded to the surfaces of the welding terminal portions 53A, 53B, 53C, and as shown in FIG. 12B, solder bumps 10A protruding from the first surface 51a of the printed wiring board 51 are formed. The

  In the printed wiring board 51 of the first embodiment as described above, unlike the conventional printed wiring board 1 shown in FIGS. 18 and 19, the front-side surfaces of the solder-welded terminal portions 53A, 53B, and 53C are different. The surface is substantially the same as the surface of the first surface-side insulating layer 57A. Therefore, when the solder ball 10 is mounted and welded, it is possible to prevent the occurrence of problems as in the case of the conventional printed wiring board 1 shown in FIGS.

  That is, in the case of the conventional printed wiring board 1 shown in FIGS. 18 and 19, the front-side surfaces of the solder-welded terminal portions 3A, 3B, and 3C are recessed from the surface position of the first surface-side insulating layer 7A. The lower part of the solder ball 10 is inserted into the recess 9A and welded. Therefore, if the diameter of the solder ball 10 varies, there are various problems as described above (see FIG. 24). there were.

  However, in the case of the printed wiring board 51 according to the first embodiment of the present invention, the solder balls 10 are not inserted into the recesses but are stepped at the boundary with the flat surface (the boundary with the surface of the first surface side insulating layer 7A). Therefore, even when the diameter of the solder ball 10 is large, the solder ball 10 is securely attached when the solder ball is mounted. , 53B and 53C, so that the solder can be reliably welded to the surfaces of the welding terminal portions 53A, 53B and 53C. Even when the diameter of the solder ball 10 is small, the solder bump 10A after melting can be formed in a state of protruding upward from the surface position of the first surface side insulating layer 57A.

  Moreover, in the printed wiring board 51 of 1st Embodiment, the surface of the terminal part 53A, 53B, 53C for soldering is flush with the 1st surface 51a, and the recessed part 9A as shown in FIG. Since there is no shoulder 9a, the probe pin does not come into contact with the shoulder when the circuit continuity test is performed before the solder ball is mounted. The reliability and certainty of the continuity test can be improved by contacting the surfaces of the terminal portions 53A, 53B and 53C for solder welding.

  Furthermore, in the printed wiring board 51 of the first embodiment, the solder welding terminal portions 53A, 53B and 53C have side surfaces 53a (boundary surfaces with the first surface side insulating layer 57A) 53a facing from the surface to the inside. Thus, it is formed in a tapered shape so as to have a taper in a direction in which the diameter increases. Furthermore, the inner end portions 53b of the solder welding terminal portions 53A, 53B, and 53C have a diameter larger than the maximum diameter of the tapered portion, and are embedded in a state where they are biting into the main support 56. Therefore, the solder welding terminal portions 53A, 53B, 53C are firmly held in the first surface side insulating layer 57A, and as a result, are welded to the surfaces of the solder welding terminal portions 53A, 53B, 53C. The solder bump 10A is also firmly held together with the solder welding terminal portions 53A, 53B, and 53C.

  Here, when the taper angle θ of the solder welding terminal portions 53A, 53B, and 53C exceeds 80 °, the side surfaces of the solder welding terminal portions 53A, 53B, and 53C are close to the vertical direction, and the solder welding terminals are caused by the taper. The effect of holding the portions 53A, 53B, and 53C is reduced. On the other hand, when the taper angle θ of the solder welding terminal portions 53A, 53B, 53C is less than 30 °, the thickness of the portion surrounding the surface of the solder welding terminal portions 53A, 53B, 53C in the first surface side insulating layer 57A is small. There is a possibility that the strength of the portion may be reduced due to the reduction in size. Therefore, the taper angle θ is preferably in the range of 30 ° to 80 °, and more preferably in the range of 40 ° to 60 °.

  Moreover, by using a composite material of a curable resin and an inorganic material as the material of the first surface side insulating layer 57A and the second surface side insulating layer 57B, and by setting the content of the inorganic material in the composite material to 60 wt% or more, The strength and rigidity of the first surface side insulating layer 57A and the second surface side insulating layer 57B can be increased. However, if the content of the inorganic substance exceeds 85 wt%, the proportion of the resin is relatively small, moldability becomes difficult, and base cracks (laminated voids) may occur. Therefore, the inorganic content in the composite material is desirably 60 wt% or more and 85 wt% or less.

  Furthermore, if the difference between the inorganic content contained in the composite material of the first surface side insulating layer 57A and the inorganic content contained in the composite material of the second surface side insulating layer 57B is 5 wt% or less, the first The surface-side insulating layer 57A and the second surface-side insulating layer 57B have the same rigidity, and as a result, it is possible to reduce the occurrence of warping of the printed wiring board due to the difference in rigidity between both surfaces. Of course, the difference between the inorganic content contained in the composite material of the first surface side insulating layer 57A and the inorganic content contained in the composite material of the second surface side insulating layer 57B is most preferably zero.

  Next, FIG. 3 shows in principle the cross-sectional structure of the main part (near the terminal part) of the printed wiring board of the second embodiment in which the present invention is applied to a two-layer printed wiring board. FIG. FIG. 2 is a plan view showing the vicinity of a terminal portion of a printed wiring board according to a second embodiment shown in FIG.

  In the case of the printed wiring board 51 of the second embodiment shown in FIGS. 3 and 4, the connecting terminal portion 54A and the connecting terminal portion among the connecting terminal portions 54A, 54B, 54C on the second surface 51b side. 54B is electrically connected to the second surface-side circuit pattern portion 90 made of a conductor layer connecting between them. The Ni plating layer 58B and the Au plating layer 58A are formed on the entire surface of the connection terminal portions 54A and 54B and the second surface side circuit pattern portion 90. Other parts are the same as those of the printed wiring board according to the first embodiment shown in FIGS.

  Next, an example of a method for manufacturing the printed wiring board according to the first embodiment shown in FIGS. 1 and 2 will be described in principle with reference to FIGS.

In the manufacturing method shown in FIGS. 5 to 11, the following steps S1 to S10 are roughly performed in that order.
S1: A first insulating resin layer that forms a first insulating resin layer 32 to be the first surface-side insulating layer 57A on a printed wiring board of a final product on one surface of a temporary support metal plate 31 prepared in advance. Forming process.
S2: A first opening forming step in which the first opening 33 is formed by laser processing in the first insulating resin layer 32 where the solder welding terminal portions 53A, 53B, 53C are to be formed. In the first opening forming step S2, the first opening 33 passes through the first insulating resin layer 32 in the thickness direction, and the opening cross-sectional area perpendicular to the thickness direction of the insulating resin from the opening end to the inside. The taper is formed to be reduced.
S3: The first insulating resin layer 32 is subjected to pattern plating with a conductive metal, and includes portions that should become solder welding terminal portions 53A, 53B, and 53C, and portions that should become the solder welding terminal portions 53A, 53B, and 53C. A first surface side conductor layer forming step of forming a first surface side conductor layer 36 embedded in the first opening 33.
S4: A third insulating resin layer forming step for forming the third insulating resin layer 37 to be the main support so as to cover the surface of the first insulating resin layer 36 and the surface of the first surface-side conductor layer 36.
S5: In the third insulating resin layer 37, at the position to be the inter-surface conduction portion 55 between any solder welding terminal portion on the printed wiring board of the product and the corresponding connection terminal portion, 3rd opening part formation process which forms the 3rd opening part 39 which penetrates the 3 insulating resin layers 37 in the thickness direction. The third opening forming step S5 is not always essential, but is necessary when obtaining a printed wiring board having the inter-surface conduction portion 55. Further, in the third opening forming step S5, the opening area of the third opening 39 in the cross section parallel to one plate surface of the base is set to the second opening from the first surface side conductor layer 36 side by laser processing. It is desirable to form in a taper shape so as to expand toward the surface side conductor layer 42 side.
S6: A second surface-side conductor layer forming step of pattern-plating the third insulating resin layer 37 with a conductive metal to form the second surface-side conductor layer 42 including a portion to be a connection terminal portion. When the third opening forming step (J) is performed in order to obtain the printed wiring board having the inter-surface conductive portion 55 as described above, the third opening is formed in the second surface side conductor layer forming step S6. Pattern plating is performed so that the conductor metal is embedded in the portion 39.
S7: Second insulating resin layer formation for forming the second insulating resin layer 43 to be the second surface side insulating layer 57B so as to cover the surface of the third insulating resin layer 37 and the second surface side conductor layer 42. Process.
S8: A second opening forming step of forming the second opening 44 in the second insulating resin layer 43 so that the surface of the portion to be the connection terminal portion in the second surface side conductor layer 42 is exposed.
S9: A terminal plating step of forming protective plating layers 58A and 58B on the surface of the portion to be the connection terminal portion in the second surface side conductor layer 42. This terminal plating step (S9) is not necessarily essential, but it is desirable to carry out the protection for the connection terminal portion.
S10: A temporary support metal plate removing step of removing the temporary support metal plate 31 covering the surfaces of the first insulating resin layer 32 and the first surface-side conductor layer 36.
Hereinafter, the steps S1 to S10 will be described more specifically in order.

<Insulating resin layer forming step S1>
As shown in FIG. 5A in advance, for example, a copper plate is prepared as the temporary support metal plate 31. The temporary support metal plate 31 does not remain in the final printed wiring board product, and plays a role of supporting an intermediate product (intermediate product) during the manufacturing process of the printed wiring board. The temporary support metal plate 31 may be made of a metal having rigidity, and basically the type thereof is not limited. However, the relationship with the electroless copper plating applied in the subsequent manufacturing process and the availability are easily obtained. From the viewpoint of cost and the like, it is preferable to use a copper plate, and the thickness thereof is not particularly limited, but usually it is preferably within a range of about 0.05 to 0.4 mm.

  As shown in FIG. 5B, the first insulating resin layer 32 is laminated or coated on one surface of the temporary support metal plate 31 as shown in FIG. The first insulating resin layer 32 is a layer to be the first surface side insulating layer 57A in the printed wiring board of the final product, and a composite material of insulating resin and inorganic substance is used. And as this composite material, it is preferable to define insulating resin and an inorganic substance so that the mixture ratio of an inorganic substance may exist in the range of 60-85 wt% as mentioned above.

<First opening forming step S2>
Further, as shown in FIG. 5C, a plurality of openings (first openings) 33 are formed in the first insulating resin layer 32 from the outer surface side by laser processing. These first openings 33 are formed at locations corresponding to the solder welding terminal portions 53A, 53B, and 53C in the printed wiring board of the final product. These first openings 33 are formed so that the diameter thereof decreases from the outer surface of the first insulating resin layer 32 to the inner side (toward the plate surface of the temporary support metal plate 31), that is, temporary support. The side surface 33 </ b> A is formed in a tapered shape so that the opening area in a cross section parallel to the plate surface of the metal plate 31 for use decreases toward the plate surface of the temporary support metal plate 31. The taper angle at this time corresponds to the taper angle θ of the solder welding terminal portions 53A, 53B, and 53C. Therefore, the taper angle of the side surface 33A of the first opening 33 is in the range of 30 ° to 80 ° as described above, and more preferably in the range of 40 ° to 60 °.

  Next, as a preliminary step of the subsequent first-surface-side conductor layer forming step S3, as shown in FIG. 5D, the entire outer surface is subjected to electroless metal plating, for example, electroless copper plating, so that the conductive seed layer 34 is formed. Form. The conductive seed layer 34 is formed so as to cover the inner surface of the opening 33, and therefore the side surface 33A of the opening 33 is electrically connected from the outer surface position to the inner surface position of the first insulating resin layer 32. It will be in the state conducted to.

<First surface side conductor layer forming step S3>
Furthermore, as shown in FIG. 5E, after plating resists 35A and 35B made of a photosensitive resin are laminated on both surfaces, as shown in FIG. As shown in A), electrolytic copper plating (pattern plating) is performed to form the first conductive layer 36 having a predetermined pattern. The first conductive layer 36 is a layer that should become the welding terminal portions 53A to 53C on the first surface 51a side in the printed wiring board of the final product. Therefore, said pattern plating is performed with the pattern of the welding terminal parts 53A-53C in the printed wiring board of a final product. Then, as shown in FIGS. 6A to 6B, after removing the resists 35A and 35B, as shown in FIGS. 6B to 6C, the conductive seed layer 34 exposed on the surface, that is, The conductive seed layer 34 is removed at locations exposed on the outer surface of the temporary support metal plate 31 and the outer surface of the insulating resin layer 32.

<Third insulating resin layer forming step S4>
Subsequently, as shown in FIG. 6D, a third surface is formed so as to cover the outer surface on the second surface 51b side, that is, the surface of the first conductive layer 36 and the surface of the first insulating resin layer 32 therebetween. An insulating resin layer 37 is formed (laminated). In this case, the third insulating resin layer 37 is usually laminated by using a copper foil 38 attached on one side, but the copper foil 38 is not always necessary. Here, the insulating resin layer 37 is a layer to be the main support 56 in the final printed wiring board. Therefore, as the insulating resin layer 37, an insulating resin such as an epoxy resin or a phenol resin is used as described above.
<Third opening forming step S5>
Then, as shown in FIG. 6 (E), a predetermined portion in the third insulating resin layer 37 (penetration penetrating in the thickness direction so as to electrically connect the welding terminal portion 53B and the connecting terminal portion 54B in FIG. 1). A via (third opening) 39 is formed in the conductive portion (a portion corresponding to the inter-surface conductive portion) 55 by drilling by laser processing. The via 39 is formed so as to penetrate the third insulating resin layer 37 from the copper foil 38 in the thickness direction.

  Further, as a preliminary step before the next second surface side conductor layer forming step S6, as shown in FIG. 7A, the seed layer 40 is formed entirely by electroless copper plating. Here, since the seed layer 40 is also formed on the inner side surface of the via 39, the inner side surface of the via 39 extends from the opening end of the via 39 to the layer to be the welding terminal portion 53B in the first conductive layer 36. Is electrically connected.

<Second surface side conductor layer forming step S6>
Next, as shown in FIG. 7B, after plating resists 41A and 41B made of a photosensitive resin are laminated or coated on both surfaces, the resist is exposed and developed into a predetermined pattern as shown in FIG. 7C. As shown in FIG. 7D, electrolytic copper plating (pattern plating) is performed to form the second conductive layer 42 having a predetermined pattern. The second conductive layer 42 is a layer to be the connection terminal portions 54A to 54C on the second surface 51b side in the printed wiring board of the final product. Therefore, the pattern plating is performed in the pattern of the connection terminal portions 54A to 54C on the final printed wiring board.

  Then, as shown in FIGS. 7D to 8A, after the plating resists 41A and 41B are peeled off, as shown in FIGS. 8A to 8B, the second surface 51b side has a second side. The seed layer 40 and the copper foil 38 that cover the surface of the third insulating layer 37 between the conductive layers 42 are removed.

<Second insulating resin layer forming step S7>
Thereafter, as shown in FIG. 8C, the second insulating resin layer (solder-resist) is formed so as to cover the second conductive layer 42 and the entire third insulating layer 37 on the second surface 51b side. 43 is laminated or applied. The second insulating resin layer 43 is a layer to be the second surface side insulating layer 57B in the printed wiring board of the final product, and uses a composite material of insulating resin and inorganic substance. Accordingly, as described above, the composite material of the second insulating resin layer 43 is preferably determined so that the mixing ratio of the inorganic resin and the inorganic material is within the range of 60 to 85 wt%. At the same time, the inorganic content contained in the composite material of the first insulating resin layer 32 to be the first surface side insulating layer 57A and the second insulating resin layer (solder) to be the second surface side insulating layer 57B. It is desirable that the difference between the resist and the inorganic content contained in the composite material is within a range of 0 to 5 wt%.

<Second opening forming step S8>
Next, as shown in FIG. 8D, the second opening 44 is formed in the insulating resin layer (solder resist) 43 for the portions to be the connection terminal portions 54A to 54C in the conductive layer 42. The conductive layer 42 is exposed to the second surface 51b side through the second opening 44. Here, a specific method for forming the second opening 44 in the second insulating resin layer (solder resist) 43 as described above is not particularly limited, but depending on the material of the insulating resin layer, for example, laser Processing may be applied, or opening may be performed by patterned exposure and development.

<Terminal plating process S9>
Next, protective plating, for example, Ni / Au plating is performed on the surface of the conductive layer 42 to be the connection terminal portions 54A to 54C.
For example, first, as shown in FIG. 9A, plating resists 45A and 45B are laminated on both surfaces, and then exposed and developed as shown in FIG. 9B. For example, the entire first surface side is plated. The surface of the second conductive layer 42 on the second surface 51b side is exposed while being covered with the resist 45A. Thereafter, as shown in FIGS. 9C and 9D, Ni plating and Au plating are performed in that order by, for example, electrolytic plating, and the underlying Ni plating layer 46 and the surface Au plating layer 47 are formed. Thereafter, the plating resists 45A and 45B are peeled and removed to obtain the state shown in FIG.

<Temporary Support Metal Plate Removal Step S10>
Thereafter, the temporary support metal plate 31 made of a copper plate is removed. For example, as shown in FIG. 10B, first, a mask 48 made of an acrylic resin that is insoluble in the copper etching solution is laminated or applied to the entire surface on the second surface 51b side. That is, lamination is performed so as to cover the surfaces of the second conductive layer 42 and the second insulating resin layer (solder resist) 43.

  Then, as shown in FIGS. 10B to 10C, if necessary, unnecessary peripheral portions are cut off by a router or the like. Further, as shown in FIG. 11A, the temporary supporting metal plate 31 made of, for example, a copper plate is etched and removed with an etching solution such as sulfuric acid + hydrogen peroxide. Thereafter, as shown in FIGS. 11A to 11B, the mask 48 is peeled off and removed. As a result, the first conductive layer 36 is exposed to the first surface 51a side. Note that the surface of the first conductive layer 36 is substantially flush with the surface of the insulating resin layer 32.

  At the stage of FIG. 11B, the printed wiring board shown in FIGS. 1 and 2 is obtained. That is, the first conductive layer 36 constitutes solder welding terminal portions 53A, 53B, and 53C that are flush with the first insulating resin layer 32 on the first surface 51a side, and is in the second opening 44. The exposed second conductive layer 42 forms connection terminal portions 54A, 54B, and 54C on the second surface 51b side.

  Thereafter, as described with reference to FIGS. 12A and 12B before the printed wiring board is shipped or on the user side, the surface (conductivity) of the solder-welded terminal portions 53A, 53B, and 53C. Solder balls 10 are deposited on the surface of the layer 42.

  In the printed wiring board manufacturing process of the embodiment as described above, the temporary support metal plate 31 such as a copper plate is used from the initial stage (FIG. 5A), and each layer is formed based on the temporary support metal plate 31. Lamination or removal, and finally the temporary support metal plate 31 is removed at the stage shown in FIG. 10C to FIG. Processing is performed. Therefore, from the initial stage to the final stage of the manufacturing process, the strength and rigidity of the intermediate product are compensated by the temporary support metal plate 31. Therefore, it is possible to prevent intermediate products from warping, deformation, waviness, etc. due to insufficient strength and rigidity, and as a result, deformation of the intermediate products may hinder transportation, transfer, handling, etc. between processes. Can be prevented from occurring.

  The example of the specific manufacturing method for the printed wiring board according to the first embodiment shown in FIGS. 1 and 2 has been described above. The printed wiring board according to the second embodiment shown in FIGS. Can also be manufactured by the same manufacturing method. That is, in that case, the pattern plating step for forming the connection terminal portions 54A, 54B, 54C on the second surface 51b side shown in FIGS. 7B to 8A, that is, the second surface 51b side. In the step of electroplating the second conductive layer 42 in a predetermined pattern, the portion to be the connection terminal portion 54A and the portion to be the connection terminal portion 54B are connected by a conductor. What is necessary is just to form the part used as the 2nd surface side circuit pattern part 90 by performing electroplating with a pattern. Other steps may be the same as those of the printed wiring board manufacturing method of the first embodiment described above.

  Further, FIG. 13 shows an example of a printed wiring board according to an embodiment having a multilayer structure (in this case, a structure having four inner conductor layers) as the printed wiring board according to the third embodiment of the present invention. The same elements and portions as those of the above-described printed wiring board of the first embodiment are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof is omitted.

  In FIG. 13, the first surface side insulating layer 57A formed on one surface side (first surface 51a side) of the entire printed wiring board, and the other surface side (second surface 51b side) of the printed wiring board. Two inner conductor layers 59A and 59B are formed in a predetermined pattern in parallel with the plate surface in each main support 56 between the second surface-side insulating layer 57B and the second surface-side insulating layer 57B. In this example, two inner conductor layers 59A and 59B are formed at positions corresponding to the solder welding terminal portions 53A, 53B and 53C and the connection terminal portions 54A, 54B and 54C. , 59B are not necessarily limited to positions corresponding to the solder welding terminal portions 53A, 53B, 53C and the connection terminal portions 54A, 54B, 54C.

Furthermore, an example of the manufacturing process of the printed wiring board (multilayer board) of the third embodiment will be described with reference to FIGS. 14 (A) to 16 (D).
Of the manufacturing process of the printed wiring board having the two-layer structure described above (FIGS. 5A to 11B), the process shown in FIG. 8B, that is, the process of removing the seed layer 40 is performed. The same applies to the manufacturing process of the printed wiring board (multilayer board) of the third embodiment. Therefore, the description and illustration of the steps prior to the step shown in FIG. 8B are omitted for the manufacturing steps of the printed wiring board (multilayer board) of the third embodiment. That is, FIG. 14A shows a state at the same stage as FIG. 8B, and the subsequent steps will be described.

In FIG. 14A, the seed layer 40 that covers the surface of the third insulating layer 37 between the second conductive layers 42 on the second surface 51b side is provided, as shown in FIG. 8B. The removed state is shown. Next, as shown in FIG. 14B, an insulating layer 91 is laminated. As this insulating layer 91, a copper foil 92 is stuck on one side in the same manner as the third insulating resin layer 37 in the manufacturing process of the two-layer structure printed wiring board described with reference to FIG. However, the copper foil 92 is not always necessary.
Furthermore, as shown in FIG. 14C, unnecessary peripheral parts are cut off by a router or the like as necessary.

After that, as shown in FIG. 8D, an opening is formed in the insulating layer 91, pattern plating is performed, and the same process is repeated to obtain a laminated structure as shown in FIG. . Thereafter, the process shown in FIG. 15B and subsequent steps is applied. The process shown in FIG. 15B and subsequent steps is substantially the same as the process after FIG. 9A in the manufacturing process of the two-layer structure printed wiring board. Since it is the same, the details are omitted.
In this way, a printed wiring board having a multilayer structure (see FIGS. 13 and 16D) can be obtained.

  A situation in which the solder bump 10A is formed by welding the solder ball 10 to the surface of the solder-welded terminal portion 53A, 53B, 53C (surface of the conductive layer 36) of the printed wiring board of the obtained multilayer structure printed wiring board Is shown in FIG. Since the situation is the same as that of the printed wiring board having the two-layer structure already described, the description thereof is omitted.

[Experimental example]
In the printed wiring board of the present invention, as described above, a composite material of a curable resin and an inorganic material is used as the material of the first surface side insulating layer 57A and the second surface side insulating layer 57B, and the inorganic material in the composite material is used. It is desirable to make the content of 60 wt% or more and 85 wt% or less, and the inorganic content contained in the composite material of the first surface side insulating layer 57A and the inorganic material contained in the composite material of the second surface side insulating layer 57B The difference from the content of is desirably 5 wt% or less. With respect to the influence of the inorganic content in the composite material of each of the insulating layers 57A and 57B, the present inventors conducted the following experiment.

  Epoxy resin was used as the resin of the composite material for each of the insulating layers 57A and 57B, and silica was used as the inorganic substance. The total thickness is 0.095 mm, the thickness of the first surface side insulating layer 57A is 0.030 mm, and the thickness of the second surface side insulating layer 57B is 0.030 mm. A printed wiring board was manufactured. When the amount of warpage per 200 mm length in the direction along the plate surface was examined after leaving the product for 3 days, the results shown in Table 1 were obtained.

  From the results shown in Table 1, the inorganic content in each insulating layer is set to 60 wt% or more and 85 wt% or less, and the difference between the inorganic content in the first surface side insulating layer and the second surface side insulating layer is determined. It was confirmed that the amount of warpage can be suppressed to a small value by setting it to 5 wt% or less.

  The preferred embodiments and experimental examples of the present invention have been described above, but the present invention is not limited to these embodiments and experimental examples. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention.

10 Solder Ball 10A Solder Bump 31 Temporary Support Metal Plate 32 First Insulating Resin Layer 33 First Opening 36 First Conductive Layer 37 Third Insulating Resin Layer 39 Third Opening (Via)
42 Second conductive layer 43 Second insulating resin layer (solder resist)
44 2nd opening 51 Printed wiring board 51a 1st surface 51b 2nd surface 52 Base | substrate 53A, 53B, 53C Solder-welding terminal part 54A, 54B, 54C Connection terminal part 55 Through-conductive part (inter-surface conduction part)
56 Main support 57A First surface side insulating layer 57B Second surface side insulating layers 59A, 59B Inner conductor layer 90 Second surface side circuit pattern portion

Claims (11)

A plurality of soldering terminal portions are embedded on the side of one plate surface of the base made of an insulating material as a whole so as to be exposed on the one plate surface, and the other plate surface of the base is formed. In the double-sided printed wiring board in which a plurality of connection terminals are embedded on the side,
In the solder welding terminal portion, the surface exposed on the one plate surface side of the base body is substantially flush with the surface of the base body,
The solder welding terminal portion is a portion embedded in the base so that an area of a cross section parallel to the one plate surface of the base increases toward the other plate surface inside the base. A printed wiring board having a tapered side surface. In the printed wiring board according to claim 1,
A double-sided printed wiring board having a conductor pattern formed on both sides of the substrate,
A plurality of portions of the conductor pattern on one side of the base are the solder welding terminal portions,
A plurality of portions of the conductor pattern on the surface on the other side of the base are the connection terminal portions,
The base is a plate-like main support, a first surface-side insulating layer formed on one surface side of the main support, and a second surface formed on the other surface side of the main support. A side insulation layer,
The printed wiring board, wherein the solder welding terminal portion is embedded in the first surface side insulating layer, and the connection terminal portion is embedded in the second surface side insulating layer. In the printed wiring board according to claim 2,
Each of the first surface side insulating layer and the second surface side insulating layer has a structure in which 60 to 85 wt% of an inorganic substance is blended in an insulating resin, and the amount of inorganic material blended in one insulating layer and the other insulating layer is The printed wiring board is characterized in that the difference is in the range of 0 to 5 wt%. In the printed wiring board according to any one of claims 1 to 3,
Any one or more solder welding terminal portions of the solder welding terminal portions and any one or more connection terminal portions of the connection terminal portions penetrate the base in the thickness direction. A printed wiring board characterized in that it is electrically connected by a through conductive portion (inter-surface conductive portion). In the printed wiring board according to claim 4,
The penetrating conductive portion (inter-surface conductive portion) has a cross-sectional area parallel to the one plate surface of the base so as to expand from the first surface side conductor layer side toward the second surface side conductor layer side. And a printed wiring board having a tapered side surface.   The printed wiring board according to any one of claims 2 to 5, wherein the first surface-side insulating layer formed on one surface side of the main support and the other surface of the main support. The number of conductor layers as a whole is such that one or more inner conductor layers are formed in a predetermined pattern in parallel to the plate surface in the main support body between the second surface-side insulating layer formed on the first side. A printed wiring board having a multilayer structure of 3 or more. A method of manufacturing a printed wiring board for manufacturing the printed wiring board according to claim 2,
A first insulating resin layer forming step of forming a first insulating resin layer to be a first surface side insulating layer in a printed wiring board of a final product on one side of a temporary supporting metal plate prepared in advance;
A first opening forming step of forming a first opening by laser processing at a position where the solder welding terminal portion is to be formed in the first insulating resin layer;
The first insulating resin layer is subjected to pattern plating with a conductive metal, and includes a portion to be the solder welding terminal portion, and the portion to be the solder welding terminal portion is embedded in the first opening. A first surface side conductor layer forming step of forming a first surface side conductor layer;
A third insulating resin layer forming step for forming a third insulating resin layer to be the main support so as to cover the surface of the first insulating resin layer and the surface of the first surface-side conductor layer;
A second surface side conductor layer forming step of performing pattern plating with a conductive metal on the third insulating resin layer to form a second surface side conductor layer including a portion to be the terminal portion for connection;
A second insulating resin layer forming step of forming a second insulating resin layer to be the second surface side insulating layer so as to cover the surface of the third insulating resin layer and the second surface side conductor layer;
A second opening forming step of forming a second opening in the second insulating resin layer so that a surface of a portion to be the connection terminal portion in the second surface side conductor layer is exposed;
A temporary support metal plate removing step of removing the temporary support metal plate covering the surfaces of the first insulating resin layer and the first surface side conductor layer;
In the first opening forming step, the first opening is cut through the first insulating resin layer 32 in the thickness direction and perpendicular to the thickness direction of the insulating resin from the opening end to the inside. Forming in a tapered shape that reduces the area,
A printed wiring board manufacturing method characterized by the above. In the manufacturing method of the printed wiring board according to claim 7,
further,
Between the third insulating resin layer forming step and the second surface side conductor layer forming step,
In the third insulating resin layer, a third insulation is provided at a place to be an inter-surface conduction portion between any solder welding terminal portion on the printed wiring board of the product and the corresponding connection terminal portion. Including a third opening forming step of forming a third opening penetrating the resin layer in the thickness direction;
In the second surface side conductor layer forming step, pattern plating is performed so that a conductor metal is embedded in the third opening.
A printed wiring board manufacturing method characterized by the above. In the manufacturing method of the printed wiring board according to claim 8,
In the third opening forming step, the opening area in the cross section parallel to the one plate surface of the base is changed from the first surface side conductor layer side to the second surface side by laser processing. It is formed in a taper shape so as to expand toward the conductor layer side.
A printed wiring board manufacturing method characterized by the above. In the manufacturing method of the printed wiring board according to any one of claims 7 to 9,
further,
Between the second opening forming step and the temporary support metal plate removing step,
Including a terminal plating step of forming a protective plating layer on the surface of the portion to be the connection terminal portion in the second surface side conductor layer,
A printed wiring board manufacturing method characterized by the above. In the manufacturing method of the printed wiring board according to any one of claims 7 to 10,
As the first surface side insulating layer and the second surface side insulating layer, a composite material in which 60 to 85 wt% of an inorganic substance is mixed with an insulating resin is used, and the composite material of one insulating layer and the other insulating layer are used. The difference in the amount of inorganic substance in the composite material is in the range of 0 to 5 wt%.
A printed wiring board manufacturing method characterized by the above.

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