JPH03225992A - Surface mount printed circuit board and its manufacture - Google Patents

Abstract

PURPOSE:To eliminate a drop in the reliability of the position of a component at the time of center support mounting operation, which is caused when a solder resist comes into contact with the component by a method wherein a surface mounting component (chip) is supported by a surface mounting pad on a substrate in such a way that the bottom part of the surface mounting component does not come into contact with the solder resist. CONSTITUTION:A surface component mounting pad 4 is formed of the following: a conductor circuit 2' which has been formed of a copper foil 2 on an insulating substrate 1; and a copper-plated film 3 which has been formed selectively on its surface by a copper-plating operation. The thickness of the copper-plated film 3 is formed to be thicker than a solder resist 5 which has been formed in advance on a conductor circuit 2'' formed only of the copper foil 2 on the insulating substrate 1. The height of the surface component mounting pad 4 is always higher than that of the solder resist 5. when an electronic component is mounted, it is constituted that the rear surface of a surface mounting chip 6 does not come into contact with the surface of the solder resist 5 by keeping a prescribed interval.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a surface-mounted component-mounted printed circuit board and a manufacturing method thereof.

(Conventional technology 1) Conventionally, when mounting electronic components such as chips, selectively etching the copper foil on the substrate 1 and the copper plating film 3 thereon as shown in FIG. ,
Copper foil conductor circuits 2', 2' are formed, and the copper plating film 3 on 2' is formed as a surface pad 4, an electronic component 6 is mounted on this pad 4, and connected with solder 1o. there were. At that time, as shown in the figure, a solder resist 5 is applied to insulate the conductor circuit 8 under the mounting of the component 6 and also to serve as an adhesive to fix the component 6 to the base material. A groove is provided in the periphery of the conductor circuit 8 in order to absorb the 5.

Note that this type of imposition related to printed circuit boards is disclosed in, for example, Japanese Unexamined Patent Publication No. 1-69091.

Problems to be Solved by the Invention] 4. In the above conventional technology, no consideration is given to the height of the solder resist 5 applied to the lower part of the component in the case of imposition, and the height of the solder resist is If the mounting pad is higher than the mounting pad 4, the bottom of the component will come into contact with the solder resist 5, and the connecting part of the component 6 will float above the mounting pad 4, resulting in unstable positioning when mounting the component. In addition, there are problems such as a decrease in reliability due to the stress exerted on the component 6 due to the solidification of the solder resist 5 in the contact area, and further heat deterioration of the solder resist 5 in the component contact area due to heat generated by the mounted component 6. Therefore, the purpose of the present invention is to solve the above-mentioned problems, and the first purpose is to provide a highly reliable printed circuit board on which mounted components can be mounted, and the second purpose is to improve the printed circuit board. The purpose of this invention is to provide a method for manufacturing the same.

[Means for Solving the Problems 1] The above object is achieved by securing a gap between the bottom surface of the component and the surface of the solder resist existing under the component.

Hereinafter, the means for achieving the object of the present invention will be specifically explained in detail. The first object is to: (1) have a conductor circuit pattern formed on at least one surface of an insulating substrate and a pad provided on a part of the conductor circuit pattern; In a component-mounted printed circuit board in which a pad of an electronic component is soldered and connected to a pad, the surface-mounted area below the mounting area of the electronic component is a solder resist coated on a conductive circuit pattern existing adjacent to the pad. (2) The above-mentioned imposition is carried out by a component-mounted printed circuit board. Under the electronic component that is surface-mounted solder-connected to the board, the gap provided between the solder resist surface that covers the conductive circuit pattern and the component is located outside the pad area of the electronic component that is surface-mounted solder-connected. The imposition described in (1) above, which is provided with a concave portion, is performed by a component-mounted printed circuit board, and (3) the depth of the concave portion is made deeper than the thickness of the solder resist film, preferably at least 15. The imposition described in (2) above, which is formed by using a component-mounted printed circuit board, and (4) a conductive circuit pattern formed by coating at least one surface of an insulating substrate with a solder resist, and the above-mentioned In a printed circuit board having an imprint formed on a part of a conductive circuit pattern with its principal surface exposed and a pad for connecting a component, the imprint is formed by a surface of the pad for connecting the component covering the conductive circuit pattern. The surface mounting, which is arranged higher than the solder resist surface, is achieved by using a printed circuit board for mounting components.

The second purpose is to (5) form a conductive circuit pattern including connection pads for the imprinted components on at least one surface of the insulating substrate by etching; Imposition is a printed circuit board for mounting components, which includes the steps of exposing the surface and selectively coating the board containing the conductor circuit pattern with a solder resist, and then applying conductor plating to the main surfaces of the connection pads. Depending on the manufacturing method of the board, and (6) imposition on at least one surface of the insulating board, after forming a conductor circuit pattern including connection pads for components by etching, the board is heated to form a predetermined pattern. The above-mentioned imposition of the lower area where the electronic component is mounted is performed by applying pressure on the conductor circuit pattern existing adjacent to the connection pad of the component, and applying pressure to the lower part of the conductor circuit pattern in the solder resist film that will be later covered in the board. Implanting is a process of embedding a solder resist deeper than the thickness of the component, and then coating the board with a solder resist in an area other than the main surface of the connection pad of the component, including the conductor circuit pattern. (7) The imposition described in (6) above, in which the insulating substrate is made of a heat-resistant resin plastic that can be plastically deformed by heating, is a printed circuit board for mounting. This is achieved by a method for manufacturing a substrate.

8- [Function 1] The printed circuit board of the present invention has a structure in which the bottom of the component (chip) does not come into contact with the solder resist when surface-mounted. As a result, the components are supported by the pads when mounting on a surface, and the pads are used when mounting on the board, which eliminates the deterioration in reliability of component position during mounting due to central support, which occurs when conventional solder resist contacts, and improves reliability by an even higher level. will improve. Further, it is also possible to prevent the solder resist from deteriorating due to mechanical stress caused by the contact of the component with the solder resist and thermal stress due to heat generated by the component.

[Example] Example 1 An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1(a) is a perspective cross-sectional view of a printed circuit board on which electronic components are mounted according to the present invention. Figure 1 (b
) is a sectional view taken along line A-A' in FIG. 1(a).

As shown in FIG. 1(b), the component mounting pad 4 according to the present invention includes a conductive circuit 2' formed of a copper foil 2 on an insulating substrate 1, and a conductive circuit 2' formed by copper foil 2 on the top surface thereof. The thickness of the copper plating film 3 is as follows.

A conductor circuit 2″′ formed only of copper foil 2 on an insulating base material 1
The height of the component mounting pad 4 is always higher than the solder resist 5 when mounting electronic components. The bottom surface of is solder resist 5
The structure is such that it does not come into contact with the surface of the substrate at a predetermined distance. When comparing the reliability of surface solder connection between the structure shown in FIG. 1(b) and the conventional structure shown in FIG. According to this embodiment, the defective rate due to misalignment of the connecting terminals could be reduced to about 174 compared to the conventional method.

Example 2 Next, a method for manufacturing a printed circuit board having a component mounting pad for imposition shown in FIG. 1 will be described in FIGS.
This will be explained with reference to the process diagram shown in Figure (e).

As shown in FIG. 2(a), copper foils 2 are laminated on both sides of an insulating base material 1 such as a glass-epoxy laminate, and through holes 9 are formed at predetermined positions by drilling or punching, and then P d / S is formed. n to form a chemical copper plating catalyst layer (not shown).

Next, as shown in FIG. 2(b), in order to form conductive circuits 2' and 2# of copper foil 2 at predetermined positions, an etching resist pattern 7 of a predetermined shape is formed by a printing method or an exposure method.

Then, as shown in FIG. 2(c), conductor circuits 2', 2''
After removing the remaining copper foil 2 by etching, the etching resist 7 is peeled off.

Next, as shown in FIG. 2(d), the surface mounting is performed by attaching a conductive circuit 2 that forms a component mounting pad forming part and a through hole land.
Except for 11', at least for imposition, a well-known plating-resistant solder resist is formed on necessary parts including the area under the component on the conductor circuit 2' by a printing method or an exposure method.

Next, as shown in FIG. 2(e), chemical copper plating 3 is deposited on the exposed conductive circuit 2' and in the through holes 9, and component mounting pads 4 are formed on the surface. The thickness of the copper plating 3 at this time is the thickness of the solder resist 5 on the conductor circuit 2'.
The thickness shall be greater than or equal to .

The surface-mounted component mounting pad 4 formed in this way is
Since the surface mounting is higher than the top surface of the solder resist 5 formed on the conductor circuit 2# in the area under the component, as shown in FIG. and does not come into contact with the solder resist 5. Further, in this embodiment, since the height of the component mounting pad 4 can be secured in the same process as the through-hole plating process, there is no need to increase the number of processes for this purpose.

Example 3 Another example of the present invention will be described with reference to FIGS. 3 and 4.

As shown in the cross-sectional view of Fig. 3, for surface mounting, the component mounting pad 4
The conductor circuit 8 formed between the M edge base 12 and the material 1 is embedded, and the amount of embedding is greater than the thickness of the solder resist 5 on the conductor circuit 8. The lower surface of the solder resist 6 does not come into contact with the surface of the solder resist 5.

The imposition shown in FIG. 3 is similar to that shown in FIGS.
This will be explained using the manufacturing process diagram shown in Figure (c).

As shown in FIG. 4(a), according to the conventional subtracting method, the pads 4 and the conductive circuits 8 between them are formed. These are formed of copper foil conductor circuits 2', 2' and copper plating film 3, and have the same height.

Next, as shown in FIG. 4(b), the temperature was raised to the glass transition point (90°C to 100°C) of the insulating base material 1 or higher, and the temperature was increased to 40'q.
/+nm" ~ 10 Qkg/+om2, and the conductor circuit 8 in the area under the component is placed inside the insulating base material 1 with a predetermined thickness of the solder resist 5 that will be formed in the subsequent process. Embed to a depth greater than .

Next, as shown in FIG. 4(c), a solder resist 5 is applied.
By forming by a printing method or an exposure method, it is possible to obtain a substrate in which the surface of the pad 4 is higher than the upper surface of the solder resist 5.

Embodiment 4 As another embodiment of the present invention, as shown in FIG. By providing, for example, 15 recesses, it is possible to obtain a board in which the surface of the solder resist 5 does not come into contact with the bottom surface of the component 6 even in a board formed by the conventional subtract method.

〔Effect of the invention〕

As detailed above, according to the present invention, with surface mounting, the chip components do not come into contact with the solder resist, so surface mounting can improve positioning reliability during mounting and prevent deterioration of the components and solder resist due to stress, etc. Therefore, it is possible to obtain a component-mounted printed circuit board by imposition with high mounting reliability.

[Brief explanation of drawings]

FIG. 1(a) is a cross-sectional perspective view of a printed circuit board with mounted components, which is an embodiment of the present invention, and FIG. 1(b) is its A.
-A' sectional view, FIG. 2 is a sectional view showing the manufacturing process of the substrate in FIG. 1, FIG. 3 is a sectional view of another embodiment of the present invention, and FIG. 4 is the manufacturing process of the substrate in FIG. 3. FIG. 5 is a cross-sectional view of still another embodiment of the present invention, and FIG. 6 is a cross-sectional view of a conventional substrate. <Explanation of symbols> 1... Insulating base material 2... Copper foil 3... Copper plating film 4... Component mounting pad for surface mounting 5... Solder resist 6... Chip component for surface mounting 7... Etching resist pattern 8... Conductor circuit

Claims (7)

[Claims] 1. It has a conductor circuit pattern formed on at least one surface of an insulating substrate, and an imposition pad provided on a part of this conductor circuit pattern, and a pad of an electronic component is connected to the imposition pad by soldering. In the printed circuit board with surface-mounted components, there is a space between a solder resist surface coated on a conductive circuit pattern existing adjacent to the surface-mounted pad in the region below the mounting of the electronic component and the component on the surface facing the solder resist. A printed circuit board on which surface-mounted components are mounted, which is formed by providing a gap and connecting the components by soldering. 2. Under the electronic component connected to the surface-mounted printed circuit board on which the surface-mounted component is mounted, the gap provided between the solder resist surface covered with the conductor circuit pattern and the component is connected to the surface-mounted solder of the electronic component. 2. The surface-mounted component-mounted printed circuit board according to claim 1, wherein a recess is provided in a portion outside the pad area. 3. 3. The surface-mounted component-mounted printed circuit board according to claim 2, wherein the depth of the recess is greater than the thickness of the solder resist film. 4. A conductor circuit pattern formed by coating at least one surface of an insulating substrate with a solder resist, and a connection pad for a surface-mounted component formed with its main surface exposed on a part of the conductor circuit pattern. 1. A printed circuit board for mounting surface-mounted components, wherein a surface of a connection pad of the surface-mounted component is disposed higher than a surface of a solder resist covering the conductive circuit pattern. 5. After forming a conductive circuit pattern including connection pads of surface-mounted components on at least one surface of the insulating substrate by etching, the main surface of the connection pads of the surface-mounted components is exposed and the conductor circuit pattern is selectively formed. 1. A method for manufacturing a printed circuit board for mounting surface-mounted components, comprising the steps of: forming a solder resist on a substrate containing the solder resist, and then applying conductor plating to the main surface of the connection pad. 6. After forming a conductor circuit pattern including connection pads for surface-mounted components on at least one surface of an insulating substrate by etching, the substrate is heated to form a pattern of the surface-mounted components in a predetermined area under mounting electronic components. Pressure is applied to the conductor circuit pattern existing adjacent to the connection pad to bury the lower part of the conductor circuit pattern deeper into the substrate than the thickness of the solder resist film that will be coated later, and then the surface mounting. A method of manufacturing a printed circuit board for mounting surface-mounted components, comprising the step of coating a solder resist on a substrate including a conductor circuit pattern in an area other than the main surface of a connection pad of a component. 7. 7. The method of manufacturing a printed circuit board for mounting surface-mounted components according to claim 6, wherein the insulating substrate is made of a heat-resistant plastic material that can be plastically deformed by heating.