JP2000208917A - Manufacture and material of circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method of manufacturing a circuit board which enables a preliminary solder pattern to be formed easily and precisely, on a fine-pitch pad and a suitable material of the circuit board using the method. SOLUTION: A method of manufacturing a circuit board comprises a step of forming single-layer or multilayer wiring patterns 22, 24, etc., electrically connected with a metal layer 12 on the side of an insulating resin layer 16 of a board material 10, wherein a solder layer 14 is formed on one surface of the metal layer 12 and the insulating resin layer 16 is formed on the other surface of the metal layer 12, and a step of etching the solder layer 14 and the metal layer 12 to form a pad pattern 28, wherein solder 14a coats a pad 12a formed of the metal layer 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a circuit board on which electronic components such as semiconductor chips are flip-chip connected and mounted, and a substrate material suitable for the method.

[0002]

2. Description of the Related Art In recent years, semiconductor chips have become more and more highly integrated, and the pitch between their terminals has become narrower. The semiconductor chip is mounted with bumps made of solder balls attached to the terminals, and flip-chip connected to pads of a circuit board such as a mounting board or a package via the bumps. Preliminary solder for connecting the semiconductor chip is attached and formed in advance on pads of the circuit board such as the mounting board or the package on which the semiconductor chip is mounted.

[0003]

By the way, the formation of the preliminary solder on the pads of the circuit board is generally performed by applying a solder paste by a printing method. However, as described above, since the pitch between the terminals on the semiconductor chip side is narrowed, the pitch between the pads on the circuit board side is necessarily narrowed, which makes it difficult to form preliminary solder on the pads by a printing method. Have been. More specifically, if the pitch between the pads is up to about 200 μm, a preliminary solder can be formed by a printing method.
Some 80 μm or less also appear, making it difficult to align with a mask, or bleeding a solder paste. For this reason, it is difficult to form a preliminary solder on these narrow pitch pads by a printing method.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a circuit board on which a pre-solder can be easily and accurately formed on a narrow pitch pad. And a substrate material suitable for use in the method.

[0005]

The present invention has the following arrangement to achieve the above object. That is, in the method of manufacturing a circuit board according to the present invention, a solder layer is formed on one surface side of a metal layer, and on the insulating resin layer side of a substrate material having an insulating resin layer formed on the other surface side of the metal layer, A step of forming a single-layer or multilayer wiring pattern electrically connected to the metal layer, and etching the solder layer and the metal layer,
Forming a pad pattern in which solder is applied to the upper surface of the pad formed by the metal layer.

[0006] Since the solder layer and the metal layer are etched using the substrate material to form a pad pattern in which the solder is applied to the pads, even if the pads have a narrow pitch, they can be easily and accurately placed on the pads. Solder can be formed well.

The step of forming the wiring pattern can suitably employ a step by a build-up method. Further, the step of forming the pad pattern is performed in two steps of a step of etching the solder layer and a step of etching the metal layer using the solder layer left by the etching step as a mask, thereby improving accuracy. be able to.

Further, the substrate material according to the present invention is characterized in that a solder layer is formed on one side of a metal layer, and an insulating resin layer is formed on the other side of the metal layer. The substrate material is
It is suitable for use in the manufacture of the circuit board.

[0009]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an explanatory sectional view of a substrate material 10. The substrate material 10 has a three-layer structure in which a solder layer 14 is formed on one surface (one surface) of a copper foil 12 which is an example of a metal layer, and an insulating resin layer 16 is formed on the other surface of the copper foil 12. The thickness of the copper foil 12 is not particularly limited, but is preferably about 5 to 10 μm. The thickness of the solder layer 14 is preferably about 30 to 50 μm. The thickness of the insulating resin layer 16 is preferably about 20 to 100 μm.

The solder layer 14 is formed on the copper foil 12 by solder plating. Or conversely, solder sheet (layer) 1
Copper foil 12 may be formed on copper foil 4 by copper plating. The insulating resin layer 16 is formed by attaching a filler-containing epoxy resin film to the other surface of the copper foil 12 with an adhesive. Alternatively, an epoxy resin containing a filler is applied to the other side of the copper foil 12 and cured to form an insulating resin layer 16.
May be formed. Note that the insulating resin layer 16 need not be mixed with a filler.

FIG. 2 shows a process of manufacturing a semiconductor package, which is an example of a circuit board, by using the above-mentioned substrate material 10. First, as shown in FIG. 1A, a hole 18 reaching the surface of the copper foil 12 is formed in the insulating resin layer 16 by laser processing. Next, the holes 18 are filled with a conductive paste 20 (FIG. 2B).

The wiring pattern 2 is formed by a known means.
The substrate material 1 shown in FIG. 3B is electrically connected to the wiring pattern 22 via the conductive paste 20 on the surface of the multi-layer or single-layer substrate 26 on which the layers 2 and 24 are formed.
0 are laminated (FIGS. 3C and 3D). Next, a photosensitive resist (not shown) is applied onto the solder layer 14, exposed and developed to form a resist pattern, and the resist pattern is used as a mask to etch the solder layer 14 with an etchant (for example, an aqueous nitric acid solution). Thus, a required solder pattern is formed (FIG. 3E).

Then, the copper foil 12 is etched with an etching solution (for example, an aqueous solution of cupric chloride) using the solder 14a left in the above etching process as a mask, and the pad on which the solder (preliminary solder) 14a is attached (adhered). 12a
Is formed (FIG. 1F). In some cases, the pad layer 28 may be formed by simultaneously etching the solder layer 14 and the copper foil 12 with a common etching solution.

The formation of a single-layer or multilayer wiring pattern on the insulating resin layer 16 may be performed by a build-up method. That is, after drilling the hole shown in FIG. 2A, electroless copper plating and then electrolytic copper plating are performed to form a copper plating film (not shown) in the hole 18 and on the insulating resin layer 16. This copper plating film is electrically connected to the copper foil 12 via the plating film in the hole 18. Then, a copper plating film is formed into a required wiring pattern by etching.

In the case of a multilayer, an insulating resin layer (not shown) is further applied or laminated on the wiring pattern to form
After forming a hole, a plating step, and an etching step, it is formed into a required multi-stage wiring pattern.

In the present embodiment, the solder layer 14 and the copper foil 12 are etched by using the above-described substrate material having a three-layer structure, and the pad pattern 28 in which the solder is attached to the pad is formed.
Is formed, solder (preliminary solder) can be easily and accurately formed on a narrow-pitch pad.

FIG. 3 shows a semiconductor package 30 formed by the above build-up method. 32 is an internal wiring pattern. Preliminary solder 1 is placed around the pad 12a.
A solder resist layer 34 is formed so as to expose 4a. Further, a solder resist layer 34 is also formed around the outermost pad (external connection terminal) 33 on the opposite side to the pad pattern 28, and a solder ball (bump) 35 for external connection is attached to the pad 33.

The semiconductor chip 36 is flip-chip connected by the preliminary solder 14a via bumps 37 formed on the semiconductor chip 36 and mounted on the semiconductor package 30. A gap between the semiconductor chip 36 and the solder resist 34 is filled with an underfill agent 38. The semiconductor device completed as described above has a solder ball 35
Is mounted on the mounting board 40 via the.

The semiconductor package 30 may be a face-down type semiconductor package 30 shown in FIG. 4 in addition to the face-up type semiconductor package shown in FIG. That is, the solder balls (bumps) 35 are attached to the pads 33 of the package on the same side as the side on which the semiconductor chip 36 is mounted. The other configuration is the same as that shown in FIG.

In the above description, the semiconductor package 30 has been described as an example of the circuit board using the substrate material 10.
The application of the substrate material 10 is not limited to the above.
For example, the present invention can be applied to a case where the semiconductor device in the mounting board 40 is connected to pads (not shown) of the mounting board 40 via the solder balls 35. Also in this case, the preliminary solder is previously attached to the pads of the mounting board 40. The mounting board including the pads (not shown) to which the preliminary solder has been applied is replaced with the above-described board using the board material 10. It can be manufactured in a similar manner.

FIG. 5 shows still another embodiment of the method of manufacturing a circuit board. In the present embodiment, the wiring pattern 2
2 and 24 are formed, and the substrate material 10 is laminated on a substrate 26 on which a pin-shaped bump 27 is formed on the wiring pattern 22 by plating or conductive paste.
The bump 27 of No. 6 is made to penetrate the insulating resin layer 16 of the substrate material 10, and the bump 27 is connected to the copper foil 12. Even in this way, it is possible to manufacture a laminated substrate substantially similar to that shown in FIG. And the figure (e)
Through the same steps as in (f) and (f), it is possible to obtain a circuit board in which the solder 14a is attached (adhered) to the pad 12a.

In this case, as shown in FIG. 1, the substrate material 10 may be one in which a solder layer 14 is formed on one side of a copper foil 12 and an insulating resin layer 16 is formed on one side in advance. As shown in FIG. 5, the insulating resin layer 16 may be separated, and may be interposed between the substrate 26 and the copper foil 12 at the time of lamination.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to these embodiments, and it is possible to make various modifications without departing from the spirit of the invention. Of course.

[0024]

According to the method of manufacturing a circuit board according to the present invention, as described above, a solder layer and a metal layer are etched using a board material to form a pad pattern in which solder is applied to a pad. Therefore, even if the pad has a narrow pitch, the solder can be easily and accurately formed on the pad. Further, the substrate material according to the present invention is suitable for use in manufacturing the circuit board.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a substrate material.

FIG. 2 is a manufacturing process diagram of a semiconductor package which is an example of a circuit board.

FIG. 3 is an explanatory cross-sectional view illustrating an example of a semiconductor package of a fus-up type;

FIG. 4 is an explanatory cross-sectional view showing an example of a semiconductor package of a twist-down type;

FIG. 5 is an explanatory view showing another method of manufacturing the circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate material 12 Copper foil 12a Pad 14 Solder layer 14a Solder 16 Insulating resin layer 18 Hole 22, 24 Wiring pattern 26 Insulating layer 28 Pad pattern 30 Semiconductor package 32 Internal wiring pattern 34 Solder resist layer 35 Solder ball (bump) 36 Semiconductor chip 37 bump 40 mounting board

Claims (4)

[Claims] 1. A solder layer is formed on one side of a metal layer,
Forming a single-layer or multilayer wiring pattern electrically connected to the metal layer on the insulating resin layer side of a substrate material having an insulating resin layer formed on the other surface side of the metal layer; And etching the metal layer to form a pad pattern in which solder is applied to the upper surface of the pad formed by the metal layer. 2. The method according to claim 1, wherein the step of forming the wiring pattern is a step based on a build-up method. 3. The step of forming the pad pattern,
2. The method according to claim 1, further comprising: a step of etching the solder layer; and a step of etching the metal layer using the solder layer left in the etching step as a mask.
Or the method for manufacturing a circuit board according to 2. 4. A solder layer is formed on one side of the metal layer,
A substrate material, wherein an insulating resin layer is formed on the other surface of the metal layer.