JPH10294549A - Manufacture of printed wiring board and printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the density and to improve the electric characteristics by mounting a bare chip component, a surface mount component, and a pin insertion type component together. SOLUTION: When the printed wiring board on which the bare chip component and a soldered component are both mounted is manufactured by this method, plating resist is applied to circuit wires formed on an insulating substrate 2 and bonding pads 7 are plated. Then the plating resist is peeled off and solder resist 1 is applied to the substrate except soldered component pads to form a solder coat. Cutting is performed in a coating range 9 of resin sealing the bare chip component to expose the bonding pads 7, thereby giving a step to the coating range.

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 printed wiring board and a printed wiring board, and more particularly to a method of mixing a bare chip component, a surface mount component, and a pin insertion type component to achieve higher density and improved electrical characteristics. The present invention relates to a method for manufacturing a printed wiring board and a printed wiring board.

[0002]

2. Description of the Related Art When manufacturing a printed circuit board on which a large number of chip components and bare chip ICs are mixedly mounted, high-density wiring is possible while maintaining connection reliability without requiring a large number of plated leads, thereby reducing manufacturing costs. A method of manufacturing a printed wiring board to be performed is disclosed in Japanese Patent Application Laid-Open No. H4-222181.

In the method of manufacturing a printed wiring board disclosed in this publication, after a conductor pattern is formed on a printed board, nickel and gold are plated on the entire conductor pattern by electroless plating, and then a bare chip IC is mounted. The area excluding the area to be covered is covered with a plating resist, and subsequently, the area other than the plating resist is plated with gold by electrolytic plating. By doing so, both a chip component electrically connected by soldering and a bare chip IC electrically connected by wire bonding can be mounted under favorable conditions.

FIGS. 7 and 8 are a top view and a sectional view of a printed wiring board. Bonding pads 7 are formed on insulating substrate 2 and surface mount component pads 5 are formed. In the figure, reference numeral 9 denotes a sealing resin application range. On the bonding pad 7 formed by etching the Cu (copper) wiring on the insulating substrate 2, a Ni + Au plating layer 19 is formed to a thickness of 5 μm and 0.05 μm on the entire wiring by electroless plating. Thereafter, a plating resist 10 for masking the wiring other than the solder resist 1 and the wire bonding portion is applied, and A is applied by electrolytic plating.
The u-plated layer 12 is formed to a thickness of 0.5 μm. Finally,
The plating resist 10 is peeled off.

[0005]

However, the above-mentioned conventional method for manufacturing a printed wiring board has the following problems. That is, (1) Since the preliminary soldering is not applied to the surface mount component pad 5, the reliability of soldering and the productivity such as the correction of component misalignment decrease. (2) When performing preliminary soldering on the surface mount component pad 5, it is necessary to perform reflow after performing solder printing, which increases the number of steps. (3) When resin sealing is performed on the bare chip component, the structure in which the resin application range 9 is not limited is not used, so that the component mounting impossible range becomes large due to the influence of the application range. (4) In order to limit the application range of the resin for sealing the bare chip component, it is necessary to print a green body such as silk printing, and the electrical characteristics fluctuate. (5) Since all the circuit wirings are plated with Au, in a soldered component, a metal compound of the solder and Au is generated, and the joint becomes brittle.

[0006]

According to the present invention, there is provided a method of manufacturing a printed wiring board and a method of manufacturing a printed wiring board in which bare chip components and soldered components are mixedly mounted. A step of applying a plating resist to circuit wiring formed on the insulating substrate and plating the bonding pads, a step of peeling the plating resist, applying a solder resist other than the soldering component pads, and applying a solder coat; And performing a cutting process on an application range of the resin for sealing the bare chip component, exposing a bonding pad, and forming a step in the application range.

Here, after the plating resist is stripped, a step of using two types of solder resists having different stripping methods, stripping one of the solder resists, exposing the bonding pads, and simultaneously forming a step in the application range. Having. The plating is Ni and Au plating.

A printed wiring board according to the present invention is a printed wiring board on which bare chip components and soldered components are mixedly mounted. Au plating is applied to bonding pads, solder coating is applied to the soldered components, and the bare chip components are sealed. It has a structure that limits the application range of the resin to be stopped.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method for manufacturing a printed wiring board and a printed wiring board according to the present invention will be described with reference to the drawings.

FIG. 1 shows bare chip components, surface mount components,
A top view of a printed wiring board for mixed mounting of pin insertion components is shown.

The range of application of the resin for sealing the bare chip component surrounding the bonding pad 7 is made lower by providing a step with respect to the solder resist 1 in the hatched portion, thereby limiting the range for blocking the resin to be sealed. . In the shape in this range, it is preferable to provide an R at a corner when mechanically cutting. When this range is small, a circle may be used. The manufacturing method of the bonding pad 7 and the surface mount component pad 5 will be described below with reference to FIGS.

First, a description will be given of a manufacturing process in which only the bonding pads 7 of the Cu wiring on the insulating substrate 2 are plated with Au. In FIG. 2, Cu wiring of the bonding pad 7 and the surface mounting component pad 5 is formed to a wiring thickness of 18 μm by a subtractive method or an additive method, and a plating resist 10 masking portions other than the bonding pad 7 is applied.

The plating resist 10 uses a screen printing or liquid photoresist ink. As a curing method, there are a heat drying type and a UV curing type, and as a peeling method, there are an alkali peeling type and a solvent peeling type. The composition component is a high acid value rosin-modified maleic resin, a rosin-modified phenol resin, a novolak phenol resin,
Acrylic copolymers, styrene / maleic acid resins, etc. are used. For the solvent stripping type, rubber-based resins, chlorinated polyolefin, cumarone resins, etc. are used.

Next, the underlying Ni plating 1 is applied only to the bonding pad 7 by performing the underlying Ni plating and Au plating.
1 and Au plating 12 are formed. Ni plating is performed by a modified Watts bath, a sulfuric acid bath, a sulfamine sun bath, or the like. Au plating includes a hard gold bath and a soft gold bath. For bonding, a soft gold bath using phosphoric acid or citric acid as a conductive salt is employed. The plating thickness is 5 μm for Ni and 0.5 μm for Au. After Au plating, the plating resist 10 is peeled off.
The insulating substrate 2 is made of a material having a high glass transition temperature, such as heat-resistant glass epoxy, glass polyimide, and bismaleid triazine, since there is a bonding step during assembly.

Next, a description will be given of a manufacturing process in which a solder coat is applied only to a portion requiring a solder coat, such as the surface mount component pad 5 and the through hole 3 for a pin insertion type component. FIG.
A solder resist 1 masking portions other than the portions where solder coating is to be performed, such as the surface mounting component pads 5 and the through holes 3 for pin insertion components, is applied, and a batch solder coating 13 such as a bump leveler is performed. The solder resist 1 includes a screen printing method or a photographic method using a photosensitive resist. The material is a base polymer mainly composed of a heat-curable epoxy resin or an ultraviolet-curable acrylate resin. The solder coating 13 is performed collectively by a solder leveler. In the solder leveler, after pre-heating the printed wiring board, it is soldered in a solder dipping bath, and excess solder is removed with an air knife.

Next, a manufacturing process for exposing the bonding pad to the surface and providing a step for limiting the application range of the resin for sealing the bare chip component will be described with reference to FIG. A cutting process is performed in a range where the resin is applied to the solder resist 1 shown in FIG.
2 are exposed, and the manufacturing process of the printed wiring board is completed. For the cutting, a type generally used for spot facing, in which a drill-shaped cutting edge is rotated and a cutting range is horizontally moved, is used.

FIG. 5 is a sectional view showing a state where components are mounted on the printed wiring board manufactured in the present invention.
Normally, when mounting the bare chip component 14, resin sealing is performed for component protection and mechanical holding. However, since the sealing resin 16 is applied in a semi-pulverized state, the application range expands on a plane due to its own weight. In the present invention, the application range 9 of the resin sealing is formed into a concave shape by counterbore processing, so that the step acts as a resin dam, so that the application range of the sealing resin 16 can be automatically controlled.

For mounting the bare chip component 14, an adhesive,
Use conductor paste. FIG. 5 shows a case of wire bonding, in which an Au wire having a diameter of about 30 μm is used, and bonding is performed by using heat, pressure, and ultrasonic waves together. As the sealing resin 16, an epoxy resin or a phenol resin having low hygroscopicity is used. The surface mounting component 17 supplies cream solder by a printing method or a dispensing method, and after mounting the component, reflow is performed. The composition of the cream solder is as follows: Sn (tin) 60% -Pb (lead) 40%, Sn6
A 3% -Pb 37% eutectic is commonly used, and a material such as Sn 62% -Ag 2% -Pb 36% is used to prevent the Ag-Pd (palladium) electrode of the surface mounting component 17 from being eroded by Ag.

Next, another embodiment will be described. The steps in which this embodiment is different from the above-described embodiments are a step of applying a solder resist and a step of processing a step to restrict the sealing range of the resin.

FIG. 6 shows a process of applying a solder resist according to the present embodiment. Two types of solder resist 18
Is applied as shown in FIG. Next, in the step of exposing the bonding pad, it is possible to perform selective processing by using a different resist material. After the solder coat 13 is performed, only the solder resist 18 is peeled off to obtain a structure similar to the above-described embodiment. be able to.

According to the above-described embodiment, since the surface mounting pad is not plated with Au, no alloy is generated by Au and Sn / Pb, and the reliability of soldering is improved. Further, since the preliminary soldering is performed, reliability and productivity are improved by suppressing chip standing during reflow and improving solder wettability. Furthermore, since the application range of the resin for sealing the bare chip component can be minimized, the component can be mounted near the bare chip component, and the mounting density can be improved.

The preferred embodiments of the method for manufacturing a printed wiring board and the printed wiring board according to the present invention have been described above.
However, those skilled in the art will readily understand that the present invention is not limited to only such specific embodiments, and that various modifications and alterations are possible in accordance with specific applications. Therefore,
The present invention includes such modifications.

[0023]

As described above, according to the method for manufacturing a printed wiring board and the printed wiring board of the present invention, bare chip parts, surface mount parts, and pin insertion parts are mixed, and high density and electrical characteristics are obtained. Can be improved.

[Brief description of the drawings]

FIG. 1 is a top plan view of a printed wiring board according to an embodiment of the present invention, with bare chip base for mixed mounting of bare chip components, surface mount components, and oin insertion type components.

FIG. 2 is a view showing a step of Au plating of a bonding pad (cross-sectional position 8 substrate cross-sectional view) for explaining the method of manufacturing a printed wiring board according to the embodiment of the present invention.

FIG. 3 is a solder coating process diagram for explaining a method of manufacturing a printed wiring board according to an embodiment of the present invention.

FIG. 4 is a view illustrating a process of cutting a sealing resin application range for describing a method of manufacturing a printed wiring board according to an embodiment of the present invention.

FIG. 5 is a printed circuit board component mounting diagram according to the embodiment of the present invention.

FIG. 6 is a solder resist application diagram for explaining a method of manufacturing a printed wiring board according to an embodiment of the present invention.

FIG. 7 is a board top view for explaining a conventional method for manufacturing a printed wiring board.

FIG. 8 is a cross-sectional view of a substrate for describing a conventional method of manufacturing a printed wiring board.

[Explanation of symbols]

 1, 18 Solder resist 2 Insulating board 3 Through hole for pin insertion type component 4 Circuit wiring 5 Surface mount component pad 6 Connection through hole and land 7 Bonding pad 8 Cutting position 9 Sealing resin coating range 10 Plating resist 11 Ni plating under ground 12 Au plating layer 13 Solder coat 14 Bare chip component 15 Au wire 16 Sealing resin 17 Surface mounting component 19 Ni + Au plating layer

Claims (4)

[Claims] 1. A method of manufacturing a printed wiring board in which bare chip components and soldered components are mixedly mounted, wherein a plating resist is applied to circuit wiring formed on an insulating substrate, and a bonding pad is plated. Removing the resist, applying a solder resist other than the soldering component pads, and applying a solder coat;
Performing a cutting process on an application range of the resin for sealing the bare chip component, exposing a bonding pad, and providing a step in the application range. 2. A method of removing the plating resist, using two types of solder resists having different peeling methods, removing one of the solder resists, exposing a bonding pad, and simultaneously forming a step in a coating range. The method for manufacturing a printed wiring board according to claim 1. 3. The printed wiring board according to claim 1, wherein said plating is Ni and Au plating. 4. A printed wiring board on which bare chip components and soldered components are mixedly mounted, wherein Au plating is applied to bonding pads, solder coating is applied to the soldered components, and a resin application area for sealing the bare chip components. A printed wiring board, having a structure for limiting the size of the printed circuit board.