JP2005011918A - Wiring board and its producing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board in which solder bridge is prevented without requiring solder resist because a wiring pattern is formed to be entirely recessed from an insulation layer and mounting of solder balls is facilitated by recognizing the boundary of the recess, and also to provide its producing process. <P>SOLUTION: In the wiring board provided with a conductor pattern 3a having a solder joint P, on at least one side of an insulation layer 16, outer surface of the conductor pattern 3a is entirely located lower than the outer surface of the insulation layer 16, and a level difference wall 16a is formed on the boundary to the insulation layer 16. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wiring board in which a solder connection portion is formed on at least one side, and a manufacturing method thereof. The wiring board can be suitably used as a mounting board for a semiconductor chip to which solder connection is performed or a mounting board for other electronic components.
[0002]
[Prior art]
In recent years, with the miniaturization and high functionality of electronic devices and the like, the mounting density of electronic components tends to increase, and along with this, the package form of semiconductor components has also changed to a structure corresponding to high density. For example, among the area array terminal type package forms, a ball grid array (BGA) in which solder balls are arranged in a grid shape (lattice shape) to enable reflow bonding has good mounting workability and high density. Because it is possible, it is frequently used.
[0003]
In addition, a multi-chip module (MCM) that mounts a plurality of semiconductor chips on a small substrate and enables mounting on a mother board is also widely used to increase the mounting density. Such MCM is also generally reflow bonded.
[0004]
Generally, an interposer substrate used for a package such as a BGA or a substrate for MCM is provided with terminals (pads) on the lower surface of the substrate to be soldered when mounted on a motherboard. In addition, these substrates are also being made into multilayer structures and fine patterns.
[0005]
In conventional multilayer wiring boards, wiring patterns and pads formed on the outermost surface thereof are formed on a flat insulating layer, and thus are formed in a convex shape on the insulating layer. Further, in the case of a transfer method in which a wiring pattern or the like that has been patterned in advance is transferred to the insulating layer, the wiring pattern or the like is embedded in the insulating layer, so that the surface is flat.
[0006]
As a method of bonding a solder ball to a pad or the like of such a wiring board, a method of mounting a solder ball directly on the opening by covering the outermost surface of the wiring board with a solder resist having an opening in the pad Or by dipping method. The solder paste for reflow connection is applied to the opening of the solder resist by a printing method or the like.
[0007]
On the other hand, a wiring board is known in which a solder connection portion is formed in a concave shape, and solder is formed in the concave portion by plating (see, for example, Patent Document 1). This wiring board is manufactured by forming a recess in the insulating layer in advance, forming a continuous wiring pattern up to the inside of the recess, and then covering the solder resist with the opening of the recess.
[0008]
[Patent Document 1]
JP-A-6-29654 (2nd page, FIG. 1)
[0009]
[Problems to be solved by the invention]
However, since the wiring substrate of Patent Document 1 forms a continuous wiring pattern from the outside of the recess to the inside of the recess, the wiring pattern on the outside of the recess is convex, so that solder adhesion to the portion is prevented. Solder resist coating was essential. Therefore, an effective method for preventing solder bridging or the like without coating with a solder resist has not been known so far.
[0010]
Accordingly, an object of the present invention is to prevent the solder bridging or the like without providing a solder resist and to recognize the boundary of the recess and to solder since the entire wiring pattern is formed in a concave shape with respect to the insulating layer. An object of the present invention is to provide a wiring board that facilitates mounting of balls and the like, and a method of manufacturing the same.
[0011]
[Means for Solving the Problems]
The above object can be achieved by the present invention as described below.
That is, the wiring board of the present invention is a wiring board in which a conductor pattern having a solder connection portion is provided on an insulating layer on at least one surface, and the entire outer surface of the conductor pattern is the outer surface of the insulating layer. A step wall is formed at a boundary with the insulating layer at a lower position.
[0012]
According to the wiring board of the present invention, not only the solder connection portion but also the entire outer surface of the conductor pattern is disposed at a position lower than the outer surface of the insulating layer, so that the stepped wall at the boundary can be provided without providing a solder resist. As a result, the effect of preventing solder bridges and the like is high, and even when a solder resist is provided, a sufficient effect of preventing short-circuiting can be obtained by only partially providing a solder resist. Further, since the step wall is formed at the boundary with the insulating layer, it is easy to mount the solder ball by recognizing the boundary of the recess without providing a solder resist.
[0013]
In the above, an interlayer connection in which a protective metal layer made of a different metal is formed on the inner surface of the conductor pattern, and an interlayer connector made of a different metal is formed on the inner surface of the protective metal layer It is preferable to further include a structure and another conductor pattern conductively connected to the interlayer connector. By adopting a multilayer structure through such an interlayer connection structure, it becomes easy to cope with higher density as a semiconductor chip mounting substrate or other electronic component mounting substrate. Moreover, according to this interlayer connection structure, since the upper and lower conductor patterns can be conductively connected by plating bonding via the columnar metal body, the connection reliability and durability are particularly good.
[0014]
Another wiring board of the present invention is a wiring board in which the solder connection portion is provided on at least one surface of the insulating layer, and the entire outer surface of the solder connection portion is lower than the outer surface of the insulating layer. It is arranged, and an annular (closed) step wall is formed at the boundary with the insulating layer. According to another wiring board of the present invention, since the solder connection portion is disposed at a position lower than the outer surface of the insulating layer, a solder bridge or the like can be formed by an annular step wall at the boundary without providing a solder resist. High prevention effect. Further, since the annular step wall is formed at the boundary with the insulating layer, it is easy to mount the solder ball by recognizing the boundary of the recess without providing a solder resist.
[0015]
In the above, it is preferable that the solder connection part is a columnar metal body that is conductively connected to the conductor pattern through the insulating layer. When the solder connection part is not formed together with the conductor pattern, it is necessary to conduct conductive connection with the conductor pattern of the inner layer. Therefore, by forming this with a columnar metal body, the upper and lower conductor patterns are plated with the columnar metal body. Since the conductive connection can be achieved by bonding, the connection reliability and durability are particularly good.
[0016]
Further, it is preferable that the solder connection portion is formed with a noble metal plating lower than the height of the stepped wall. Thereby, while maintaining the effect of the stepped wall to some extent, the oxidation resistance of the solder connection portion is increased, and the wettability and adhesion of solder and the like can be improved.
[0017]
On the other hand, in the method for manufacturing a wiring board according to the present invention, a coating layer made of a metal different from this is formed on the outer surface of the conductor pattern having the solder connection portion, and the outer surface of the coating layer is the surrounding insulating layer. Forming a wiring board precursor formed at substantially the same height as the outer surface of the wiring board, and removing the coating layer from the wiring board precursor to expose the conductor pattern. . Forming the metal pattern at almost the same height as the outer surface of the insulating layer can be easily performed by a transfer method or the like, so the coating layer is removed using a wiring board precursor in which the coating layer is formed on the conductor pattern. As a result, a wiring board having the above-described effects can be manufactured by a simple process.
[0018]
Further, according to another wiring board manufacturing method of the present invention, a coating layer made of a different metal is formed on the outer surface of the solder connection portion, and the outer surface of the coating layer is outside the surrounding insulating layer. The method includes a step of forming a wiring substrate precursor formed at substantially the same height as the surface, and a step of removing the coating layer from the wiring substrate precursor to expose the solder connection portion. Forming the metal pattern at almost the same height as the outer surface of the insulating layer can be easily done by transfer method etc., so the coating layer is removed using the wiring board precursor with the coating layer formed on the solder connection part By doing so, it is possible to manufacture a wiring board that exhibits the above-described effects in a simple process.
[0019]
Further, it is preferable that the coating layer is made of a metal different from the solder connection portion, and the coating layer is removed by etching. When the coating layer is made of a metal different from the solder connection portion, only the coating layer can be selectively removed by selective etching.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 are process diagrams showing an example of a method of manufacturing a wiring board according to the present invention.
[0021]
The method for manufacturing a wiring board according to the present invention is a wiring board precursor BP as shown in FIG. 4 (14), and is made of a metal different from the outer surface of the conductor pattern 3a having the solder connection portion P. A step of forming the wiring substrate precursor BP in which the coating layer 2 is formed and the outer surface of the coating layer 2 is formed at substantially the same height as the outer surface of the surrounding insulating layer 16 is included.
[0022]
In the present embodiment, as shown in FIG. 4 (15), in the present embodiment, a protective metal layer 11 made of a metal different from this is formed on the inner surface of the conductor pattern 3 a, and the protective metal layer 11 is further formed. The example further includes an interlayer connection structure in which an interlayer connection body 14a made of another metal is formed on the inner surface, and another conductor pattern 18a electrically connected to the interlayer connection body 14a.
[0023]
First, as shown in FIGS. 1 (1) to (2), on the coating layer 2 side of a laminate having a first metal layer 1 serving as a base substrate and a coating layer 2 composed of another metal, A conductor pattern 3a made of another metal is formed. In the present invention, the conductor pattern 3a has a solder connection portion P.
[0024]
At this time, any pattern forming method may be used, and examples thereof include a panel plating method in which a pattern is formed using an etching resist, and a pattern plating method in which a pattern plating resist is used for plating. In this embodiment, an example in which a pattern is formed by a panel plating method is shown.
[0025]
In that case, a laminated plate SP in which a first metal layer 1, a covering layer 2, and a metal layer 3 for forming a conductor pattern 3a are laminated as shown in FIG. The laminated plate SP may be manufactured by any method, and for example, any of those manufactured using plating, sputtering, vapor deposition, etc., or a clad material can be used. Regarding the thickness of each layer of the laminated plate SP, for example, the thickness of the first metal layer 1 is 30 to 1000 μm, the thickness of the coating layer 2 is 2 to 100 μm, and the thickness of the metal layer 3 is 1 to 100 μm.
[0026]
As will be described later, the thickness of the covering layer 2 corresponds to the height of the step wall formed at the boundary between the conductor pattern 3 a and the insulating layer 16. For this reason, as the thickness of the coating layer 2 is increased, the effect of preventing solder bridges is increased. However, if the thickness of the coating layer 2 is too large, it is disadvantageous in terms of material cost and takes time to remove. . Therefore, the preferable thickness of the coating layer 2 is, for example, 1 to 10% with respect to the width of the conductor pattern 3a.
[0027]
Usually, copper, copper alloy, nickel, tin or the like can be used as the metal constituting the conductor pattern 3a. As the metal constituting the covering layer 2, a metal different from the first metal layer 1 and the conductor pattern 3a is used, and another metal exhibiting resistance when etching these metals can be used. Specifically, when these metals are copper, another metal constituting the coating layer 2 is gold, silver, zinc, palladium, ruthenium, nickel, rhodium, lead-tin solder alloy, or nickel- A gold alloy or the like is used. However, the present invention is not limited to the combination of these metals, and any combination with another metal exhibiting resistance when the metal is etched can be used. The same applies to the metal constituting the protective metal layer 11 and the metal constituting the second metal layer 14 and the conductor pattern 3a.
[0028]
Moreover, as a metal which comprises the 1st metal layer 1, the metal different from the coating layer 2 is used, for example, copper, copper alloy, nickel, tin etc. can be used. In this invention, it is preferable that the metal which comprises the conductor pattern 3a and the metal which comprises the 1st metal layer 1 are the same, and it is preferable to use copper especially. The coating layer 2 is preferably nickel.
[0029]
Next, as shown in FIG. 1B, pattern formation is performed using the etching resist 4. As the etching resist 4, a photosensitive resin, a dry film resist (photoresist), or the like can be used. In addition, when the 1st metal layer 1 is etched simultaneously with the metal layer 3, it is preferable to provide the mask material 5 for preventing this.
[0030]
Examples of the etching method include etching methods using various etching solutions according to the types of the metals constituting the coating layer 2 and the metal layer 3. For example, when the metal layer 3 is copper and the coating layer 2 is the aforementioned metal (including a metal resist), a commercially available alkaline etching solution, ammonium persulfate, hydrogen peroxide / sulfuric acid, or the like can be used. After the etching, the etching resist 4 is removed.
[0031]
Next, as shown in FIG. 1 (3), a protective metal layer 11 that covers the conductor pattern 3a having at least the connection portion P is formed. In the present embodiment, an example in which substantially the entire surface including the non-pattern portion of the conductor pattern 3a is covered with the protective metal layer 11 is shown.
[0032]
As the metal constituting the protective metal layer 11, another metal exhibiting resistance can be used when the interlayer connector 14a is formed by etching. Specifically, when the metal constituting the interlayer connector 14a is copper, gold, silver, zinc, palladium, ruthenium, nickel, rhodium, a lead-tin solder alloy, a nickel-gold alloy, or the like can be used. In the present invention, the metal constituting the protective metal layer 11 is preferably the same as the metal constituting the coating layer 2.
[0033]
The protective metal layer 11 can be formed using electrolytic plating, electroless plating, sputtering, vapor deposition, or the like, but it is preferable to use electrolytic plating. The thickness of the protective metal layer 11 is 1-20 micrometers, for example, and 1-10 micrometers is preferable.
[0034]
Electrolytic plating can be performed by a known method. In general, while immersing the target laminated plate in a plating bath, the laminated plate is used as a cathode, and the metal ion supply source of the metal to be plated is used as an anode. This is carried out by depositing a metal on the cathode side by an electrolysis reaction.
[0035]
Electroless plating solutions are well known for various metals, and various types are commercially available. In general, the liquid composition contains a metal ion source, an alkali source, a reducing agent, a chelating agent, a stabilizer, and the like. A plating catalyst such as palladium may be deposited prior to electroless plating.
[0036]
Next, as shown in FIG. 1 (4), a second metal layer 14 made of a metal different from the protective metal layer 11 is further formed. The formation of the second metal layer 14 can be performed by electrolytic plating, electroless plating, or the like, but is preferably performed by electrolytic plating. The thickness of the second metal layer 14 corresponds to the height of the interlayer connector 14a, and can be set to, for example, 30 to 1000 μm.
[0037]
As a metal constituting the second metal layer 14, for example, copper, copper alloy, nickel, tin or the like can be used. In this invention, it is preferable that the metal which comprises the conductor pattern 3a, and the metal which comprises the 2nd metal layer 14 are the same.
[0038]
Next, as shown in FIG. 2 (5), a mask layer 15 is formed on the surface portion of the second metal layer 14 where the interlayer connector 14a is to be formed. The mask layer 15 can be formed by a method of exposure / development or screen printing after applying a photosensitive resin or laminating a dry film resist.
[0039]
The individual size (area, outer diameter, etc.) of the mask layer 15 is determined in accordance with the size of the interlayer connector 14a, and is defined as the outer diameter of the interlayer connector 14a for conductive connection (via) between wiring layers. Can be, for example, 50 to 1000 μm, and the outer diameter of the interlayer connector 14a for the heat dissipation structure can be 1000 μm or more. The mask layer 15 may have any shape, and may be a circle, an ellipse, a quadrangle, a polygon, a pattern, or the like, and the interlayer connector 14a corresponding to the shape can be formed.
[0040]
Next, as shown in FIG. 2 (6), the second metal layer 14 on which the mask layer 15 is formed is selectively etched to form an interlayer connector 14a. At this time, if the amount of erosion caused by etching is too large, the formed interlayer connector 14a may be reduced in diameter (increased undercut), which may hinder subsequent processes, and conversely, the amount of erosion is too small. Then, the second metal layer 14 may remain in the non-patterned portion, causing a short circuit. Therefore, the degree of erosion by the above etching is preferably the degree shown in FIG.
[0041]
Examples of the etching method include etching methods using various etching solutions according to the types of metals constituting the second metal layer 14 and the protective metal layer 11. For example, when the second metal layer 14 is copper and the protective metal layer 11 is the aforementioned metal (including a metal resist), a commercially available alkaline etching solution, ammonium persulfate, hydrogen peroxide / sulfuric acid, or the like can be used.
[0042]
Next, as shown in FIG. 2 (7), at least the non-patterned portions of the covering layer 2 and the protective metal layer 11 are selectively etched away simultaneously or separately. In the present embodiment, an example is shown in which the covering layer 2 and the protective metal layer 11 are formed of the same metal, and these are simultaneously removed by selective etching. If the two are different metals, they can be removed by sequential etching.
[0043]
As an etching method, an etching method using an etching solution different from the etching step shown in FIG. 2 (6) can be mentioned. However, if a chloride etching solution is used, both the metal-based resist and copper are eroded. It is preferable to use other etching solutions. Specifically, when the interlayer connector 14a and the conductor pattern 3a are copper, and the protective metal layer 11 is the above-described metal, an acid such as nitric acid, sulfuric acid, or cyan is commercially available for solder removal. It is preferable to use a system etching solution or the like.
[0044]
The pattern portion exposed by etching is preferably subjected to a surface treatment such as a blackening treatment to improve the adhesion with the insulating layer. The same applies to other conductor patterns.
[0045]
Next, as shown in FIG. 2 (8), the mask layer 15 is removed. This may be selected as appropriate depending on the type of the mask layer 15 such as removal of chemicals and removal of peeling. For example, in the case of photosensitive ink formed by screen printing, it is removed with chemicals such as alkali. At the same time, the mask material 5 may be removed.
[0046]
Next, as shown in FIG. 3 (9), the insulating layer 16 is formed on the formation surface of the interlayer connector 14a. At that time, the interlayer connector 14 a is preferably exposed from the insulating layer 16. In the present embodiment, an example is shown in which the interlayer connector 14a is exposed after the insulating layer forming material is laminated.
[0047]
First, an insulating material is applied. As the insulating material, for example, an inexpensive and reactive curable resin such as a liquid polyimide resin or an epoxy resin can be used. This may be applied by various methods so as to be slightly thicker than the height of the interlayer connector 14a, and then cured by heating or light irradiation. As a coating method, various coaters such as a curtain coater can be used. Alternatively, a hot pressing or vacuum laminating method may be used by using an adhesive sheet, a prepreg, or the like containing a reactive curable resin.
[0048]
Next, the insulating layer 16 having a thickness substantially equal to the height of the interlayer connector 14a is formed by grinding and polishing the cured insulating material. Examples of the grinding method include a method using a grinding apparatus having a hard rotary blade in which a plurality of hard blades made of diamond or the like are arranged in the radial direction of the rotary plate, and the hard rotary blade is fixedly supported while rotating. By moving along the upper surface of the wiring board, the upper surface can be planarized. Moreover, as a grinding | polishing method, the method of lightly grind | polishing by a belt sander, buff grinding | polishing, etc. is mentioned.
[0049]
Next, as shown in FIGS. 3 (10) to 3 (11), after the mask material 6 is provided on the surface on which the interlayer connector 14a is formed, the first metal layer 1 as the base substrate is removed by etching or the like. At this time, since the coating layer 2 is provided on the surface of the conductor pattern 3a, even if the conductor pattern 3a and the first metal layer 1 are the same metal, only the first metal layer 1 is removed. The etching of the first metal layer 1 can be performed in the same manner as the etching of the second metal layer 14.
[0050]
Next, as shown in FIGS. 3 (12) to 4 (14), another conductor pattern 18a electrically connected to the interlayer connector 14a is formed. In the present embodiment, the conductor pattern 18a is formed by the panel plating method similarly to the conductor pattern 3a, but may be formed by the pattern plating method.
[0051]
As described above, the coating layer 2 made of a different metal is formed on the outer surface of the conductor pattern 3a having the solder connection portion P, and the outer surface of the coating layer 2 is the surrounding insulating layer 16. The wiring board precursor BP formed at substantially the same height as the outer surface can be formed.
[0052]
As shown in FIG. 4 (15), the present invention includes a step of removing the coating layer 2 from the wiring board precursor BP to expose the conductor pattern 3a. Thereby, the conductor pattern 3a having the solder connection portion P is provided on the insulating layer 16 on at least one surface, and the entire outer surface of the conductor pattern 3a is disposed at a position lower than the outer surface of the insulating layer 16, A wiring board having a step wall 16a formed at the boundary with the insulating layer 16 can be manufactured.
[0053]
The method for removing the coating layer 2 may be any method such as etching and peeling by mechanical force, but it is preferable to remove the coating layer 2 by etching. As an etching method, when the conductor patterns 3a and 18a are copper and the coating layer 2 is the above-described metal, acid-based etching such as nitric acid, sulfuric acid, and cyan is commercially available for solder peeling. It is preferable to use a liquid or the like. Thus, when the coating layer 2 is made of a metal different from the solder connection portion P, the coating layer 2 can be removed by etching.
[0054]
In the present invention, a protective metal layer 21 made of another metal is formed on the inner surface (upper surface in the drawing) of the conductor pattern 18a, and the inner surface of the protective metal layer 21 is made of another metal. The wiring board can be multilayered by forming an interlayer connection structure in which the interlayer connector 22 is formed and another conductor pattern 23 conductively connected to the interlayer connector 22.
[0055]
For example, as shown in FIG. 5, a multi-layer wiring board having three conductive patterns can be formed. 5A and 5B are diagrams showing a usage state of an example of the wiring board of the present invention, wherein FIG. 5A is a sectional view thereof and FIG. 5B is a bottom view thereof.
[0056]
As shown in FIG. 5, when solder balls are joined to the solder connection portion P of the wiring board of the present invention and the wiring board is solder-connected to a mother board or the like, it can be connected by reflow. When the solder ball 30 is joined to the solder connection portion P, the step wall 16a is present at the boundary with the insulating layer 16, so that solder bridges and the like can be prevented without providing a solder resist, and the step wall 16a ( It becomes easy to mount the solder ball 30 by the wire bonding method or the like while recognizing the recess boundary.
[0057]
In this invention, as shown in FIG.5 (b), the conductor pattern 3a which has the solder connection part P will be in the state exposed from the recessed part bottom face of the insulating layer 16 of the surface. For this reason, when it is going to form a solder ball by the immersion method etc., a solder ball may adhere also to the conductor patterns 3a other than the solder connection part P. FIG. Even in that case, since there is the step wall 16a, a solder bridge or the like can be prevented.
[0058]
In recent years, pads (solder connection parts) such as BGA tend to be finer and denser, and the process of coating the solder resist corresponding to each pad position on the substrate by opening corresponding to each pad is positioned. It is very difficult in relation to the alignment accuracy. However, in the wiring board of the present invention, since the majority of the periphery of the solder connection portion P is surrounded by the step wall 16a, the solder connection portion P can be provided only by providing a solder resist having a plurality of openings in a slit shape, for example. Solder balls can be attached with high accuracy.
[0059]
On the other hand, as shown in FIG. 6, in another wiring board of the present invention, the solder connection portion P is provided on the insulating layer 16 on at least one surface, and the entire outer surface of the solder connection portion P is formed of the insulating layer 16. An annular (closed) step wall 16a is formed at the boundary with the insulating layer 16 and is disposed at a position lower than the outer surface. FIGS. 6A and 6B are views showing a usage state of another example of the wiring board of the present invention, in which FIG. 6A is a sectional view thereof and FIG. 6B is a bottom view thereof. In such a wiring board, a coating layer made of another metal is formed on the outer surface of the solder connection portion P, and the outer surface of the coating layer is substantially the same as the outer surface of the surrounding insulating layer 16. Manufactured by the method for manufacturing a wiring board according to the present invention, comprising: a step of forming a wiring board precursor formed on the substrate; and a step of removing the coating layer from the wiring board precursor to expose the solder connection portion P. can do.
[0060]
In the present invention, the solder connection portion P is preferably an interlayer connection body 14a that is conductively connected to the conductor pattern 18a through the insulating layer 16, and the interlayer connection body 14a is particularly preferably a columnar metal body. . In the present embodiment, as shown in FIG. 6, an example in which noble metal plating 35 is applied to the solder connection portion P is shown.
[0061]
In order to form the wiring board precursor, for example, a laminated board obtained by removing the protective metal layer 11 and the conductor pattern 3a from the laminated board shown in FIG. 2 (5) is used, and the remaining steps are shown in FIG. 2 (5) to FIG. It may be carried out in the same manner as the process shown in 4 (14). Thereby, a wiring board precursor in which the protective metal layer 11 and the conductor pattern 3a do not exist in FIG. 4 (14) can be obtained. 6 further includes a protective metal layer 21 made of a different metal on the inner surface (upper surface in the drawing) of the conductor pattern 18a, and the protective metal layer 21 has a different inner surface. The wiring board is multilayered by forming an interlayer connection structure in which an interlayer connection body 22 made of the above metal is formed and another conductor pattern 23 conductively connected to the interlayer connection body 22.
[0062]
As shown in FIG. 6, reflow solder can be joined to the solder connection portion P of the wiring board of the present invention to solder-connect the wiring board to a mother board or the like. When the solder 31 is joined to the solder connection portion P, the step wall 16a is present at the boundary with the insulating layer 16, so that solder bridging or the like can be prevented without providing a solder resist.
[0063]
In this invention, as shown in FIG.6 (b), only the solder connection part P will be exposed from the recessed part bottom face of the surface insulating layer 16, and a conductor pattern will be in the state which is not exposed. For this reason, the solder 31 can be attached only to the solder connection part P without a solder resist by a dipping method, a printing method, or the like. However, a solder resist may be provided. In that case, the size and shape of each opening of the solder resist may be different from that of the solder connection portion P.
[0064]
[Another embodiment]
Hereinafter, another embodiment of the present invention will be described.
[0065]
(1) In the embodiment shown in FIG. 6, the example in which the solder connection portion P is formed by the interlayer connector 14a that is conductively connected to the conductor pattern 18a through the insulating layer 16 is shown in FIG. As shown in the figure, the conductor pattern 3a is composed only of the solder connection portion P, and a protective metal layer 11 made of a different metal is formed on the inner surface of the conductor pattern 3a. Alternatively, an interlayer connection structure in which an interlayer connection body 14a made of another metal is formed may be provided so as to be conductively connected to another conductor pattern 18a.
[0066]
In this case, the conductor pattern 3a can be formed only by different shapes. Similarly to the above, the solder connection portion P may be formed with a noble metal plating lower than the height of the step wall.
[0067]
(2) In the above-described embodiment, an example in which a conductor pattern is formed by a panel plating method or a pattern plating method after forming an insulating layer has been described. It is also possible to form a conductor pattern layer.
[0068]
First, a laminated body (for example, FIG. 2 (8)) on which an interlayer connection body is formed is hot-pressed with a resin-coated copper foil by a pressing surface, and has a convex portion at a position corresponding to the interlayer connection body and a metal on the surface. A laminated body in which layers are formed is obtained. At this time, it is preferable to dispose at least a sheet material that allows concave deformation between the press surface and the laminated body on which the interlayer connection body is formed. Moreover, you may use the press surface which has a recessed part in the position corresponding to an interlayer connection body.
[0069]
Subsequently, the convex part of the obtained laminated body is removed, and the interlayer connection body is exposed. At that time, the portion where the upper surface of the interlayer connection body is higher than the upper surface of the metal layer of the laminate may be simultaneously removed and planarized.
[0070]
As a method for removing the convex portion, a method by grinding or polishing is preferable, a method using a grinding device having a hard rotating blade in which a plurality of hard blades made of diamond or the like are arranged in the radial direction of the rotating plate, a sander, a belt sander, Examples thereof include a method using a grinder, a surface grinder, a hard abrasive molded product, and the like. When the grinding device is used, the upper surface can be flattened by moving the hard rotary blade along the upper surface of the fixedly supported wiring board while rotating the hard rotary blade. Moreover, as a grinding | polishing method, the method of lightly grind | polishing by a belt sander, buff grinding | polishing, etc. is mentioned. When the convex portion is formed on the laminate as in the present invention, it becomes easy to grind only that portion, and the entire flattening can be performed more reliably.
[0071]
Next, the exposed interlayer connection body and the metal layer adjacent to each other with the insulating layer interposed therebetween are conductively connected. For example, if the conductor layer is formed on the substantially entire surface of the metal layer including the upper surface of the interlayer connection body by plating. Good. Thereafter, the metal layer and the conductor layer can be etched to form a conductor pattern.
[0072]
(3) In the above-described embodiment, the example in which the interlayer connection body for connecting the conductor patterns is a columnar metal body formed by etching is shown. However, the interlayer connection body in the present invention is a conductive paste, Any of plated via holes and laser filled vias may be used. For example, in the case of a laser filled via, it can be manufactured as follows.
[0073]
First, in the same manner as described above, as shown in FIGS. 8 (1) to (2), the laminated body having the first metal layer 1 serving as the base substrate and the coating layer 2 made of another metal. A conductor pattern 3a made of another metal is formed on the coating layer 2 side.
[0074]
Next, as shown in FIG. 8C, the covering layer 2 is selectively etched using the conductor pattern 3a as an etching resist. As an etching method, when a chloride etching solution is used, both the metal-based resist and copper are eroded, and therefore other etching solutions are preferably used. Specifically, the first metal layer 1 and the conductor pattern 3a are copper, and the coating layer 2 is gold, silver, zinc, palladium, ruthenium, nickel, rhodium, lead-tin solder alloy, nickel-gold alloy, or the like. In this case, it is preferable to use acid-based etching solutions such as nitric acid, sulfuric acid, and cyan that are commercially available for solder removal.
[0075]
Next, as shown in FIG. 9 (4), the insulating layer 16 is formed on the formation surface of the conductor pattern 3a. As the insulating material, for example, an inexpensive and reactive curable resin such as a liquid polyimide resin or an epoxy resin can be used.
[0076]
Next, as shown in FIG. 9 (5), an opening 16c is provided by a laser or the like at a position where the filled via FB is formed. The opening 16c can be formed by exposing and developing the insulating layer 16 with a photosensitive resin. Further, as shown in FIGS. 9 (6) to 10 (7), filled via FB and laser via LB are formed by a conventional method.
[0077]
Next, as shown in FIG. 10 (8), the first metal layer 1 is removed by etching or the like, and a coating layer made of another metal is formed on the outer surface of the conductor pattern 3a having the solder connection portion P. 2 is formed, and a wiring board precursor BP is formed in which the outer surface of the covering layer 2 is formed at substantially the same height as the outer surface of the surrounding insulating layer 16.
[0078]
Next, as shown in FIG. 10 (9), the coating layer 2 is removed from the wiring board precursor BP to expose the conductor pattern 3a. As a result, it is possible to manufacture a wiring board in which the entire outer surface of the conductor pattern 3 a is disposed at a position lower than the outer surface of the insulating layer 16 and the step wall 16 a is formed at the boundary with the insulating layer 16.
[0079]
(4) In the above-described embodiment, the example in which the first metal layer serving as the base substrate is removed by etching has been described. However, a material that can be peeled off from the insulating layer 16 may be used instead of the first metal layer. . For example, a mirror plate made of stainless steel or the like with a coating layer formed thereon, or a resin plate with a coating layer formed thereon may be used.
[0080]
(5) In the above-described embodiment, the example in which the coating layer is a metal is shown. However, the coating layer is not limited to a metal, and any material such as a resin, a low-molecular organic material, or an inorganic material that is different from the insulating layer. Can also be used. For example, when using a resin or the like of a material different from that of the insulating layer, the coating layer can be removed by selectively dissolving or decomposing it.
[0081]
(6) In the above embodiment, the example in which the removal of the mask layer is performed immediately after the metal layer is selectively etched has been described. However, the order of the removal process of the mask layer is not limited to this, and for example, the protective metal layer The mask layer may be removed immediately after the etching step or when the insulating material is ground or polished.
[0082]
(7) In the above-described embodiment, an example of a multilayer wiring board that does not have a large-area interlayer connection for heat dissipation has been described. However, a multi-layer interlayer connection may be formed. For example, it may have an interlayer connection structure that penetrates and connects conductor pattern layers provided in the upper and lower outermost layers, through which heat can be effectively radiated from the semiconductor chip to the back surface of the substrate.
[0083]
(8) In the above-described embodiment, as shown in FIGS. 3 (11) to 4 (14), after removing the first metal layer 1 as the base substrate, another conductive connection is made to the interlayer connector 14a. Although the example of forming the conductor pattern 18a has been shown, in the present invention, before the first metal layer 1 is removed, another conductor pattern 18a conductively connected to the interlayer connector 14a is formed, or a further upper layer interlayer is formed. You may remove the 1st metal layer 1 after forming a connection body and a conductor pattern.
[Brief description of the drawings]
FIG. 1 is a process diagram showing an example of a method of manufacturing a wiring board according to the present invention.
FIG. 2 is a process diagram showing an example of a method of manufacturing a wiring board according to the present invention.
FIG. 3 is a process diagram showing an example of a method of manufacturing a wiring board according to the present invention.
FIG. 4 is a process diagram showing an example of a method of manufacturing a wiring board according to the present invention.
FIGS. 5A and 5B are diagrams showing a usage state of another example of the wiring board of the present invention, wherein FIG. 5A is a sectional view thereof, and FIG.
6A and 6B are diagrams showing a usage state of another example of the wiring board of the present invention, in which FIG. 6A is a cross-sectional view thereof, and FIG. 6B is a bottom view thereof.
FIG. 7 is a cross-sectional view showing a usage state of another example of the wiring board of the present invention.
FIG. 8 is a process diagram showing another example of a method for manufacturing a wiring board according to the present invention.
FIG. 9 is a process diagram showing another example of a method of manufacturing a wiring board according to the present invention.
FIG. 10 is a process diagram showing another example of a method of manufacturing a wiring board according to the present invention.
[Explanation of symbols]
1 1st metal layer
2 Coating layer
3a Conductor pattern
11 Protective metal layer
14 Second metal layer
14a Interlayer connection body
15 Mask layer
16 Insulating layer
16a Stepped wall
18a Conductor pattern layer

Claims (8)

In the wiring board in which the conductor pattern having the solder connection portion is provided on the insulating layer on at least one surface,
The wiring board, wherein an entire outer surface of the conductor pattern is disposed at a position lower than an outer surface of the insulating layer, and a step wall is formed at a boundary with the insulating layer. An interlayer connection structure in which a protective metal layer made of a different metal is formed on the inner surface of the conductive pattern, and an interlayer connection made of a metal different from this is further formed on the inner surface of the protective metal layer; and The wiring board according to claim 1, further comprising another conductor pattern conductively connected to the interlayer connection body. In the wiring board in which the solder connection part is provided in the insulating layer on at least one surface,
The wiring board, wherein an entire outer surface of the solder connection portion is disposed at a position lower than an outer surface of the insulating layer, and an annular step wall is formed at a boundary with the insulating layer. The wiring board according to claim 3, wherein the solder connection portion is a columnar metal body that is conductively connected to the conductor pattern through the insulating layer. The wiring board according to any one of claims 1 to 4, wherein a plating of a noble metal is formed in the solder connection portion lower than a height of the step wall. A coating layer made of a metal different from this was formed on the outer surface of the conductor pattern having the solder connection portion, and the outer surface of the coating layer was formed at substantially the same height as the outer surface of the surrounding insulating layer. Forming a wiring board precursor; and
Removing the covering layer from the wiring board precursor to expose the conductor pattern. A wiring board precursor in which a coating layer made of a different metal is formed on the outer surface of the solder connection portion, and the outer surface of the coating layer is formed at substantially the same height as the outer surface of the surrounding insulating layer Forming a step;
And a step of removing the coating layer from the wiring board precursor to expose the solder connection portion. The method for manufacturing a wiring board according to claim 6, wherein the coating layer is made of a metal different from the solder connection portion, and the coating layer is removed by etching.

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