JP2575411B2 - Cross conductor manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a method for manufacturing a cross conductor, and
In particular, the present invention relates to a method for manufacturing a cross conductor that can stably manufacture a cross conductor having excellent electrical connectivity at low cost.

(Prior art and its problems) Conventionally, as a cross conductor for making an electrical connection between printed circuits in a printed wiring board or the like, generally,
Metal rods with caps as electrodes on both ends and those with small resistors formed by applying insulation coating on the surfaces of lead wires are used. There has been a problem that it takes time for fitting and insulating coating.

On the other hand, in recent years, Japanese Unexamined Patent Application Publication No. 61-292867 discloses that a laminate comprising a plurality of conductive films extending in parallel with each other at a predetermined distance between two insulating plates is used. , And a chip-shaped cross conductor that can be mass-produced and is obtained by forming a conductive surface on the cut surface where the conductive film is exposed.

However, in a cross conductor having such a structure, a ceramic green sheet is usually used as two insulating plates, and after a conductive film is formed by printing on one of the superposed surfaces, they are superposed on each other. By simultaneously firing together, it is costly to form a green sheet because it is to be manufactured, and at the time of superposition, air easily enters between the polymerized surfaces, causing swelling and the like during firing. Therefore, the problem of poor yield was inherent.

Further, in the cross conductor having such a structure, since the area of the conductive surface exposed on the cut surface is extremely small, the reliability of the conductive surface formed on the cut surface, and hence the electrical connection to the printed circuit, is reduced. It was hard to say that it was sufficient, and there were many disadvantages when it was actually adopted as a product.

(Solution) Here, the present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a chip-shaped cross conductor capable of advantageously improving electrical connectivity. Another object of the present invention is to provide a manufacturing method that can be manufactured stably at low cost.

In order to achieve this object, the gist of the present invention is to screen-print a paste of a predetermined conductive material on the surface of a ceramic green sheet that provides an electrically insulating plate-like body. By doing
A plurality of conductive films having a predetermined width extending parallel to each other at predetermined intervals are formed, and a ceramic paste for providing an electric insulating layer is screen-printed on the ceramic green sheet on the side where the conductive films are formed. Thereby, in the direction crossing the conductive film, a plurality of insulating layers each having a predetermined width and extending in parallel with each other at a predetermined interval are formed to form a laminate, and thereafter, the laminate is simultaneously fired. Thus, there is provided a method for manufacturing a cross conductor, wherein a sheet-like fired body is obtained in which a plurality of cross-conductor forming chips are continuously arranged and formed on a plane.

(Specific Configuration of the Invention) That is, in the method of the present invention, first,
Using a predetermined ceramic powder, a ceramic green sheet that gives electrical insulation by firing is formed.

By the way, various molding materials for ceramics and green sheets have been conventionally proposed, but in the present invention, in order to achieve simultaneous sintering with a conductive film described later, the sintering temperature is reduced. It is desirable that the material be low and give sufficient strength by firing. For example, in a borosilicate glass powder of 35 to 50% by weight constituting a matrix,
A material obtained by mixing alumina powder as a filler at a ratio of 50 to 65% by weight as a main raw material is preferably used. That is, the mixing ratio of such glass and alumina powder is 800 to 900 while maintaining relatively large strength.
It enables sintering at a temperature of ℃, and when the blending amount of glass is large, the obtained sintered body is not dense, and defects such as vacancies are generated inside and adverse effects such as reduced strength are caused. If the amount of alumina is large, the sintering temperature becomes high, and simultaneous firing with the conductive film becomes difficult.

Then, to such a raw material powder, a molding aid such as a binder, a plasticizer, a dispersant, and a solvent is appropriately blended and adjusted to a predetermined viscosity by kneading, and a ceramic slurry obtained thereby is used. By forming the sheet into a thin plate by an appropriate forming method, for example, a doctor blade method, and cutting it into an appropriate size, the ceramic green sheet 10 as shown in FIG. Will be formed.

In addition, as a blending ratio of such an auxiliary, generally, the raw material powder: 100 parts by weight, acrylic binder: 1 to 15 parts
Parts by weight, plasticizer: 1 to 15 parts by weight, dispersant: 0.5 to 5 parts by weight,
The organic solvent is appropriately selected within the range of 10 to 30 parts by weight. If the amount of the binder is small, the green sheet 10 is fragile and difficult to handle.On the other hand, if the amount is too large, the green sheet 10 is hard and difficult to handle and bake. While 10 is hard and easily cracked, if it is too large, the green sheet 10 becomes too soft and difficult to handle, and if there is little dispersant, the viscosity of the ceramic chiller is high and mixing becomes difficult, while the effect is increased even if it is large. This does not increase the size and adversely affects the formation of the green sheet 10. Also, when the amount of the solvent is small, the viscosity of the ceramic slurry is high and mixing cannot be performed. On the other hand, when the amount is large, the viscosity of the ceramic slurry is low and the viscosity does not reach a predetermined value, and it is difficult to form the green sheet 10.

Next, as shown in FIG. 1B, a plurality of conductive films 12 having a predetermined width and extending in parallel with each other at a predetermined interval are formed on the surface of the obtained green sheet 10. Is done. Although not shown, in the following drying operation, a guide hole for positioning is generally provided for the green sheet 10, and the conductive hole 12 and the like are accurately positioned by the guide hole. Will be formed.

The conductive film 12 is formed by screen-printing a paste of a predetermined conductive material. As the conductive material, a conductive material such as gold, silver, silver-palladium, tungsten, or molybdenum is used. As the main component, any of them can be used, and among them, gold, silver,
Alternatively, a material containing silver-palladium as a main component is suitably used.

In addition, a conductive material forming such a conductive film 12 is as follows.
In addition to metals such as gold and silver, it may contain a small amount of ceramic conductors and the like, and may contain any ceramic component such as a sintering aid such as glass or a filler. The bonding strength to the sheet 10 can be improved.

Furthermore, after forming such a conductive film 12 and drying, on the green sheet 10 on the side where the conductive film 12 is formed,
As shown in FIG. 1C, a plurality of insulating layers 14 having a predetermined width and extending in parallel with each other at a predetermined interval in a direction crossing the conductive film 12 are formed. Becomes

The insulating layer 14 is formed by screen-printing a ceramic paste that provides an electrical insulating layer by firing, and in particular, a material having the same composition as the ceramic slurry forming the green sheet 10 is used. Thereby, integration with the green sheet 10 can be advantageously achieved.

Then, the laminate 16 in which the conductive film 12 and the insulating layer 14 are formed on the green sheet 10 is dried and then heated to a predetermined temperature, so that the green sheet 10, the conductive film 12 and the The insulating layer 14 is fired at the same time, whereby a plurality of (16 in the illustrated case) cross-conductor forming chips 18 are continuously arranged and formed on a plane to form a sheet. Fired body 19
Is obtained.

Here, the conductive film 12 is made of gold, silver, or silver-
When formed of palladium, its melting point is relatively low, but by adopting a low firing temperature green sheet 10 having the above-described composition, simultaneous firing is performed at a temperature of 800 to 900 ° C. It becomes possible.

Further, in order to facilitate division of the fired body 19 into each chip 18, before the firing, as shown in FIG. It is desirable to provide a horizontal groove 22 at the center of the space between the insulating layers 14.

That is, in the fired body 19 obtained in this manner, as is clear from FIG. 1C, the conductive film 12 embedded integrally between the green sheet 10 and the insulating layer 14 is formed.
However, the structure is such that it is exposed between the insulating layers 14, and the exposed portion of the conductive film 12 is divided for each chip 18.

Incidentally, such a fired body 19 is further described in
According to the usual method as shown in 292867,
A conductive surface treatment or the like is performed, thereby forming a chip-shaped cross conductor as a product.

Specifically, for example, first, as shown in FIG. 2A obtained by dividing the fired body 19 along the transverse grooves 22 in the longitudinal direction of the insulating layer 14, body
The coating 24 is coated with a conductive paste or a conductive paint on the divided surfaces on both sides where the cut surface of the conductive film 12 is exposed, and then baked or heat-treated to obtain a structure shown in FIG.
The conductive surfaces 26, 26 are formed as shown in FIG.

Next, the divided body 24 on which the conductive surfaces 26, 26 are formed,
Each chip is placed along the vertical groove 20 in the longitudinal direction of the insulating layer 14.
Divided into 18 and the resulting chips 18
On the other hand, as shown in FIGS. 2 (c) and 2 (d), nickel electroplating and / or solder plating are applied to the respective conductive surfaces 26 and 26 and the conductive film 12. As a result, the electrodes 28, 28 are formed, whereby the cross conductor 30 as a product is obtained.
In FIG. 2, reference numeral 32 denotes an electrically insulating plate-like body as a fired body of the green sheet 10.

That is, according to the above-described method, the ceramic green sheet 10 is used only on one side of the conductive film 12, which is extremely advantageous in cost as compared with the conventional one.

Since the insulating layer 14 on the green sheet 10 on which the conductive film 12 is formed is formed by screen printing a ceramic paste, the operation is easier than the conventional green sheet bonding. It becomes.

Particularly, since the insulating layer 14 is formed by screen printing, the insulating layer 14 and the green sheet 10 are formed.
As a result, air entrapment can be avoided as much as possible, whereby a stable product quality and a reduced yield can be advantageously achieved.

Furthermore, the cross conductor manufactured by the method of the present invention
In FIG. 30, since the conductive film 12 is exposed on both side surfaces, as shown in FIGS. 2 (c) and 2 (d), the fixing area of the electrode 28 formed by the plating operation is increased. Therefore, there is an advantage that the reliability of the electrical connection of the electrode 28 and the conductive surface 26 to the conductive film 12 and the improvement of the connection strength can be effectively achieved. They have.

(Examples) Examples of the present invention will be shown below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples. That goes without saying.

In addition, in addition to the following examples, the present invention, in addition to the above-described specific description, various changes, corrections, and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It is to be understood that improvements can be made.

First, a mixture of 42.5% by weight of borosilicate glass and 57.5% by weight of alumina was wet-pulverized in a ball mill for 63 hours, dehydrated and dried to obtain a ceramic raw material powder. Next, a binder (acrylic): 14 parts by weight and a plasticizer (DB) are added to 100 parts by weight of the ceramic powder.
P): 12 parts by weight, dispersant (sorbitan trioleate): 1 part by weight, solvent (toluene): 21 parts by weight,
The mixture was mixed with a ball mill for 39 hours to form a slurry. Then, the pressure in the slurry is reduced by a vacuum pump to remove the air in the slurry and the viscosity is adjusted. Then, the ceramic green sheet is formed into a sheet shape by a doctor blade method, and the green sheet is formed into an appropriate size. The green sheet (10) was obtained by cutting into pieces. The green sheet (10) was formed with a positioning guide hole by a press in order to prevent a product from shifting in a subsequent process.

Next, on the green sheet (10) obtained, using a printing paste containing 95 parts by weight of silver and 5 parts by weight of borosilicate glass mixed with 95 parts by weight of gold, as shown in FIG. As shown in Table 2, a plurality of conductive films (12) extending in parallel with each other at predetermined intervals were formed by screen printing and dried.

Further, on the green sheet (10) on the side on which the conductive film (12) is formed, a printing paste having the same components as the ceramic slurry forming the green sheet (10) is used. As shown in the figure, in a direction crossing the conductive film (12) at a predetermined interval,
A plurality of insulating layers (14) extending parallel to each other were formed and dried.

Then, with respect to the laminated body (16) thus obtained, a vertical groove (20) and a horizontal groove (22) are formed between the conductive films (12) and between the insulating layers (14), respectively. After forming
By holding at 850 ° C for 10 minutes, the green sheet (1
0), the conductive film (12) and the insulating layer (14) are simultaneously fired, so that a plurality of cross-conductor forming chips (18) are continuously arranged and formed on a plane to form a sheet-like fired body ( 19). In the formation of the fired body (19), there is almost no occurrence of defective products due to swelling or the like at the time of firing caused by the intake of air between the green sheet (10) and the insulating layer (14). %, An extremely high yield was confirmed.

Further, as shown in FIG. 2, the obtained fired body is divided by a horizontal dividing groove (22) to form a divided body (24), and the divided body (24) is divided on both side divided surfaces. Then, a conductive surface (26) was formed by coating and drying a conductive paste containing gold as a main component. Next, the divided body (24) is divided at the vertically divided surface (20) into a chip shape, and nickel electrolysis is performed on each of the conductive surface (26) and the exposed surface of the conductive film (12). By forming the electrodes (28) by plating, a chip-shaped cross conductor (30) as a product could be obtained.

That is, in such an embodiment, the insulating layer (14)
In the formation of the electrodes, the incorporation of air into the green sheet (10) is effectively prevented, the yield can be advantageously improved, and the connection of the electrode (28) to the conductive film (12) is improved. It was confirmed that the reliability was improved, and the improvement and stabilization of the product quality could be achieved extremely advantageously.

(Effects of the Invention) As is clear from the above description, according to the method of the present invention, it is possible to extremely effectively reduce the manufacturing cost and improve the yield in manufacturing the cross conductor, and thereby the chip-shaped Practical application of the cross conductor can be advantageously achieved.

Further, in the cross conductor manufactured by the method of the present invention, since the exposed area of the conductive film can be increased, the contact area of the electrode with the conductive film can be set large. This also has the effect that connection reliability, that is, product quality can be improved.

[Brief description of the drawings]

1 (a), 1 (b), and 1 (c) are step explanatory diagrams each showing a specific example of a step of forming a laminate according to the method of the present invention. Also, FIGS. 2 (a), (b), (c),
(D) is a process explanatory view showing a specific example of a process of forming a cross conductor as a product from a fired body obtained by firing such a laminate. 10: Green sheet, 12: Conductive film 14: Insulating layer, 16: Laminated body 18: Cross conductor forming chip 19: Sintered body, 24: Divided body 26: Conductive surface, 28: Electrode 30: Cross conductor

Claims (1)

(57) [Claims] 1. A ceramic green sheet providing an electrically insulating plate-like body is screen-printed with a paste of a predetermined conductive material on a surface thereof, and extends in parallel with each other at a predetermined interval. A plurality of conductive films having a predetermined width are formed, and a ceramic paste for providing an electric insulating layer is screen-printed on the ceramic green sheet on the side on which the conductive films are formed, so that the conductive films cross each other. In the direction in which a plurality of cross conductors are formed by forming a plurality of insulating layers having a predetermined width and extending in parallel with each other at predetermined intervals to form a laminate, and then simultaneously firing such a laminate, A method for manufacturing a cross conductor, comprising obtaining a sheet-like fired body in which chips are continuously arranged and formed on a plane.