JPS5812391A - Printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed wiring board in which a lead-less step component is buried in a through-hole of a printed wiring board and connected to the printed wiring board. 0 Conventionally, leadless step components have been used as a method to efficiently and efficiently attach components to printed wiring boards for electronic devices. Proposed. In this case, many leadless chip components are mounted on the printed wiring board surface, but some attempts have been made to insert leadless snap components into holes drilled in the printed wiring board and to place leadless chip components from the printed wiring board surface. Efforts are being made to prevent protrusion.

When embedding leadless chip components in the holes of this printed wiring board, lands made of conductive foil provided on the front and back sides of the double-sided printed wiring board are soldered to the locations provided around the holes. , through-hole plating or methods such as soldering or caulking are used for insertion pins where the connection between the front and back is broken at the center.However, these methods require repeated heating by re-soldering. The leadless chip component has the disadvantage that the parts become loose, making it impossible to obtain a stable connection.The present invention is designed to attach this leadless chip component to a hole in a printed wiring board in a stable connection. An embodiment of the present invention will be described below with reference to the drawings.

Lead dresser/3 having an outer shape that matches the processed hole 4 of the double-sided printed wiring board 1, such as a round hole or a square hole.

A pull part 13 is prepared in the shape of a round bar or a square bar. Connections to the lands 2 and 3 of the double-sided printed wiring board 1 are made using conductive paint 12. As the conductive paint 12, a material with good printability that can provide solder heat resistance after baking and hardening is used. The reed step component 13 preferably has a shape in which a resistor film is formed on an insulating prismatic or cylindrical column and electrodes are provided at both ends thereof.

However, this can also be applied to laminated or wound (rotating) type capacitors, inductors, etc. made of ceramic or organic materials. In order to achieve a stable insertion state, a temporary backing plate or film 11 is used to create a bottomed plate. The conductive paint 12 is printed together with the upper surface land 2 of the double-sided printed wiring board 1, and on the other hand, for the lower electrode planned portion of the lead restraint component 13, the conductive paint 12 printed on the upper electrode planned portion is cured and then applied to the lower surface. The backing plate or film 11 is removed, and then conductive paint 12 is printed on the lower electrode portion of the leadless chip component 13 along with the lower land 3 of the double-sided printed wiring board 1.

If the viscosity of the conductive paint 12 is lowered during printing, it will penetrate in a capillary manner between the reed step component 13 and the hole wall of the printed wiring board 1, forming the front and back conductive lands 2,
A conductive path will be formed between the hole and the hole, and even if it can be used as a through-hole connection, there is a great possibility that the placement of the component in the hole will be meaningless.

Furthermore, if the viscosity is made too high, the difference in height between the electrodes of the leadless chip component 13, the surface of the printed wiring board 1, and the lands 2.degree.

In the present invention, conductive paint for printing with a normal viscosity 1
2 and a metal mask 7 having a hole 6 with steps 6 and a squeegee.
Printing is performed in combination with 8.

The amount of ink supplied can be controlled by the depth of the step 6 provided in the metal mask 7, and it is characterized by being able to print on a large number of holes at the same time. As the insulating base material of the double-sided printed wiring board 1, a glass cloth base epoxy resin/triazine resin laminate 1 with a thickness of 1.6 m is used, and a paper base phenol/paper base epoxy resin laminate is used. A film of polyester/polycarbonate, polyparaxylene, polyimide, etc. having a thickness of 0.025 to 0.1 strands or 0.025 to 0.1 strands can also be used.

Next, a specific example will be described.0 [Example 1] A conductor pattern was formed on a paper-based phenolic resin laminate with a thickness of 1.6 cm by copper foil etching, and a diameter was 1.2 Open the pharyngeal hole.

A carbon composite resistor having a length of 2.0+ m and a diameter of 1.0 mm is prepared and installed in the hole. Leet.

Adhesive tape, a polyimide film with a thickness of ■μ, and a paper-based phenolic resin laminate with a thickness of 0.4+n are prepared by adhering to the bottom of the Restep part in advance. If the adhesive is thermally cured at 120° C. for 30 minutes, the bond will be semi-permanent, but if a tacky adhesive is used, the bond will be temporary.

If the bottom forming material of the hole is 1.6fi thick, lead /(
f7 parts are 2. Oran −1,6llm=0.
There is a protruding figure at the top of 4 m. A metal mask 7 with a diameter of 1.1 mm and a diameter of 1. S
A 0.2M thick piece having a stepped circular hole 6 of 1.2 mm in diameter was prepared, and a conductor was formed on the bottom of the hole with a waist diameter of 1.2 wm using conductive paint. When a mask with this structure is used, a certain amount of conductive paint is stored in the mask and does not adhere to the hole walls. After inserting the reed step part 13 into the hole 4,
By temporarily curing at 120° C. for 30 minutes and volatilizing the dissolved 1, the lower electrode planned portion of the component is adhesively fixed. On the other hand, for the upper electrode planned portion of the lead-less step component 13, when the electrode planned portion surface is approximately the same height as the printed wiring board surface, conductor paint is applied to the upper electrode planned portion of the component and the printed wiring by screen printing. Although it may be possible to print in a form that bridges the conductor surface of the board, it is common for the general nivalry step part 13 to protrude above the printed wiring board 1, and in such cases, the stepped metal mask 7 is used to print the printed wiring board. Cross-linking printing can be performed on the printed wiring board 1 having a step and the upper electrode planned portion of the leadless chip component 13. The printed conductive paint 12 is heated and cured for 160C for 30 minutes to establish an electrical connection between the back wiring and the lower electrode of the lead-less step component 13.

Note that the round hole may be a square hole, and the cross-sectional shape of the reed step component 13 may be either round or square.

[Example 2] As shown in FIGS. 4 to 6, two sets of single-sided printed wiring boards each having a thickness of 0.8 m were prepared, and these were placed in the upper 16. The two-layer structure of the lower layer 14 is laminated with adhesive. In this case, a square hole 18 of 1.0 mm x 1.2 wm is previously formed in the upper layer wiring board 16, and the square hole 18 is placed in the lower layer wiring board 14 as a hole with a bottom. The thickness of the square hole 18 is 1. When the OLml+ lead-less step component 13 is buried with its thickness direction perpendicular to the surface of the printed wiring board, a protrusion of about 0.2+a remains. Printing of the conductive paint 12 is performed twice. That is, the first time is just before burying the leadless chip component 13, and this is the process of forming the lower electrode of the leadless chip component 13 and forming the leadless chip component 13 and the lower wiring board 14.
This is done for electrical connection with the land 16 of. The second time, after burying the leadless step component 13, the land 17 of the upper layer wiring board that is not on the same plane as the electrode planned portion of the leadless chip component 13 that protrudes from the surface of the upper layer wiring board. Printing was carried out in a cross-linked form, and at the same time as the first printing, the conditions were 150°C for 30 minutes - C way, 7) oj"5" upper layer. 5>1-'
, 7 and the underlying land 16, a packaged body of leadless chip components 13 electrically connected can be formed. For example, the conductive paint 12 has a viscosity of 80 to
A material having a range of 120 poise is used and printed using a metal mask 7 having a stepped structure. The metal mask 7 is made of stainless steel and has a thickness of 0.3 yna, step 1.
0 depth is 0.15 wm, its through hole is 0.9 x
1.1 tan, step hole part 1.4 x 1.6 tan
And so. In this example, as in Example 1, the squeegee 8 was used when printing the conductive paint 12.

As described above, according to the present invention, the electrodes of a lead-less step component can be embedded or semi-embedded in a printed wiring board while forming the electrodes, which saves time and effort in manufacturing the lead-less step component, and allows for thinner and thinner lead-less step components. It has the feature of being able to form a printed wiring board.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional perspective view of the main part of a printed wiring board showing one embodiment of the present invention, FIGS. 2 and 3 are cross-sectional views showing the connection process of the same lead-less step components, and FIG. 4 is a diagram showing another embodiment of the present invention. FIGS. 6A and 6B are cross-sectional perspective views of essential parts of the printed wiring board of the example. FIGS. 1... Printed wiring board, 2, 3... Land, 4... Hole, 12... Conductive paint, 13... Reedless step parts 0 Name of agent Patent attorney Toshio Nakao and 1 other person No.
ml, 1 Is2 Iris 3

Claims (1)

[Claims] A printed wiring characterized in that a leadless step component is embedded in a hole provided in a printed wiring board, and a portion of the leadless chip component intended for electrodes and a land made of conductive foil of the printed wiring board are connected with conductive paint. Board.