JP2000277916A - Substrate and split substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress release of a conductive member from an insulating base body by forming a conductive member to a specified depth from the surface of the insulating base in a thickness direction, and forming a split groove deeper than the conductive member in the thickness direction of the insulating base body. SOLUTION: An insulating base 10 is provided with insulating layers 10a-10h, with internal wirings 11 formed between the insulating layers 10b and 10c as well as insulating layers 10f and 10g. The internal wirings 11 are connected with a via hole conductor 12 penetrating the thickness of insulating layers 10g and 10h. The insulating base 10 is provided with a conductive member 13 so formed with a specified depth from the bottom surface of the insulating base 10 in thickness direction, with a split groove 15 so formed as to split the conductive member 13 into two. The split groove 15 is formed on the upper surface of the insulating base 10 as well so as to face the split groove 15 on the lower surface, with the split groove 15 formed on the lower surface being formed deeper than the conductive member 13 in the thickness direction of the insulting base 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate having a division groove and a division substrate having an end face electrode.

[0002]

2. Description of the Related Art In recent years, electronic devices have become smaller, lighter and more portable, and the circuit blocks used therein have been reduced in size, weight, and thickness, surface-mounted, and composited in accordance with the trend. .

[0003] In such a trend, ceramic circuit boards have been widely used from the past due to their excellent heat dissipation and low dielectric loss, and their application as a high-frequency module has been promoted.

Conventionally, a circuit board for surface mounting is used by being soldered to a mother board. Then, from the viewpoint of checking the bonding state and maintaining reliability, the surface mounting circuit board has a structure having end electrodes. From the viewpoint of the manufacturing method, the structure of the surface mounting circuit board having the end electrodes is roughly classified into three types of manufacturing methods.

The first structure is called a through-hole thick film structure, and a technique such as suction is applied to an unfired or fired substrate on which a through-hole for an end face electrode has already been formed, by using a technique such as suction. The structure is obtained by coating a conductive paste on the inner wall surface of the through-hole and baking it, and dividing by a dividing groove crossing the through-hole portion. The advantage of this structure is that the substrate can be processed in large numbers,
When divided into unit blocks, each becomes a divided substrate having a plurality of end face electrodes, which is advantageous in reducing man-hours.

The second structure is an application of the first structure, in which a through hole is formed for each unfired green sheet layer, and an inner wall surface of the through hole is coated with a conductive paste. This is a structure achieved by laminating and integrating those having a hole thick film structure, and is a structure obtained by baking and dividing by a dividing groove crossing a through hole portion. The advantage of this structure is that the internal wiring and the end face electrode can be easily joined.

[0007] The third structure is called a single formation structure. Basically, a divided substrate divided into unit blocks has a structure of one.
This is a structure obtained by a method of patterning and printing the end face electrodes using a thick film printing technique or the like for each end face. The advantage of this method is that there is no dead space due to a through hole when viewed in a mounting projection area, and the method is suitable for miniaturization.

[0008]

However, the above 3)
Each of the structures according to the various manufacturing methods has the following disadvantages. That is, the first through-hole thick film structure lacks connection reliability between the internal wiring and the end face electrode when the ceramic substrate has the internal wiring. For example, if the target is an unfired ceramic substrate, it is necessary to form a through-hole in the substrate by a punching method or the like, but the internal wiring collapses at the time of formation, making it difficult to make contact with the end face electrode.

The second structure becomes unsuitable when the width of the end face electrode is widened, similarly to the first structure. That is, in this structure,
It is difficult to coat only the inner wall surface of the through hole, but if the conductive paste is filled in the through hole formed in the green sheet, the conductive paste is required to be left only on the inner wall surface of the through hole. There has been a problem that the operation of removing the paste is required, and if the conductive paste is left as it is, an additional conductive paste is required.

[0010] Furthermore, the through hole is formed for each layer by punching or the like, and then laminated. However, due to the low lamination accuracy during lamination, the inner wall surface of the through hole becomes irregular, and the surface of the end face electrode also becomes irregular. There was a problem that it was easy.

In the first and second structures, since the dividing groove formed on the substrate surface passes through the cylindrical conductive member serving as an end surface electrode when divided, the dividing groove forms a conductive material when divided by the dividing groove. The member will be cut directly, the force at the time of splitting into conductive members will act, and the conductive members will peel off,
There is a problem that the connection reliability between the conductive member and the insulating base is reduced.

Further, the formation of a through hole is indispensable, and the through hole itself becomes a dead space,
There is a problem that the effective area of the substrate is reduced and the mounting efficiency is low.

Furthermore, various end face structures and conductor shapes have conventionally been used. However, when end face electrodes are manufactured by a punching method using a mold, design using a simple shape such as a circle and an ellipse is forced, and a conductive member is required. An end face structure excellent in connection reliability and mass productivity of the insulating substrate was not obtained.

In the third single formation structure, since the end face is exposed, a large number of pieces cannot be formed.

Therefore, when components are mounted on the surface of the substrate, it is necessary to mount the components on each of the divided substrates, which greatly reduces the mounting efficiency.

Further, in these structures, as shown in FIG. 8, since the end face electrode 41 is formed on the entire side face of the insulating base 43, there is a problem that the end face electrode 41 is easily peeled off when colliding with an electronic component or the like. Further, since it is formed on the entire side surface of the insulating base 43, a large amount of conductive paste for the end surface electrode 41 is required. Further, as shown in FIG. , Solder 44
Over the entire surface of the end face electrode 41 formed on the entire side surface of the insulating base 43, and there is a problem that a large amount of solder 44 is required.

[0017]

According to the present invention, there is provided a substrate comprising: an insulating base formed by laminating a plurality of insulating layers; a conductive member formed at a predetermined depth in a thickness direction from a surface of the insulating base; And a dividing groove that is formed deeper than the conductive member in the thickness direction and that divides the conductive member into a plurality.

Here, in a divided substrate having an insulating substrate for a divided substrate formed by laminating a plurality of insulating layers, and an end surface electrode formed on the side surface of the insulating substrate for a divided substrate, the end surface electrode includes: It is preferable that the surface of the insulating substrate for a divided substrate is formed to have a predetermined length in the thickness direction from the surface of the insulating substrate for a divided substrate, and that the surface of the end face electrode and the side surface of the insulating substrate for the divided substrate are coplanar. Further, it is preferable that an anchor conductive member formed at a predetermined depth in the thickness direction of the insulating substrate for a divided substrate is connected to the end face electrode.

[0019]

According to the substrate of the present invention, when the substrate is divided by the dividing groove, each of the divided substrates has an end face electrode. However, since the forming depth of the dividing groove is deeper than the depth of the conductive member, the substrate is embedded in the substrate. The side surface of the conductive member is exposed in the dividing groove, does not directly divide the conductive member even when dividing by the dividing groove, no stress acts on the conductive member, the conductive member from the insulating base Peeling is suppressed, and connection reliability between the conductive member and the insulating base can be improved.

Further, in the divided substrate according to the present invention, the end face electrode is
Formed at a predetermined length in the thickness direction from the surface of the insulating substrate for a divided substrate, and the surface of the end surface electrode and the side surface of the insulating substrate for the divided substrate are flush with each other. Since it is buried and the surface of the end face electrode does not protrude as in the conventional case, even if this end face electrode collides with an electronic component or the like, it does not peel off.

Conventionally, an end face electrode is formed on the entire side surface of the divided substrate. Therefore, even when the end face electrode is joined to the mother board by solder, the solder is put on the entire end face electrode. Although a large amount of paste and solder for bonding to the mother substrate were required, the present invention makes it possible to reduce the exposed area of the end face electrode to a minimum necessary area. Material cost can be reduced.

Further, by connecting an anchor conductive member formed at a predetermined depth in the thickness direction of the insulating substrate for a divided substrate to the end surface electrode, the separation of the end surface electrode from the divided substrate can be further prevented, and the inside of the divided substrate can be prevented. By connecting the internal wiring formed in the above to the anchor conductive member, the connection between the internal wiring and the end face electrode can be reliably performed.

Furthermore, by plating the surface of the end face electrode with a metal having good solder wettability, soldering to the mother board can be reliably performed even if the exposed area of the end face electrode is small.

Further, as compared with the conventional case where the end face electrodes are formed using through holes, there is no dead space on the divided substrate, so that the area in which components can be mounted is increased,
The mounting density of components can be improved.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view of a divided substrate according to the present invention. Reference numeral 1 denotes an insulating substrate for the divided substrate, and terminals such as an input / output terminal, a power supply terminal, and a ground terminal are provided. This is shown as an end face electrode 2. The end face electrodes 2 are formed so as to be exposed at a total of ten places on four side surfaces of the insulating substrate 1 for a divided substrate.

On the upper surface of the insulating substrate 1 for divided substrates,
A surface electrode (wiring) 3 is formed, and a chip component 4 such as a resistor or a capacitor is connected to the surface electrode 3.
A cavity 5 is formed in the insulating substrate 1 for a divided substrate, and a semiconductor bare chip 6 is accommodated in the cavity 5 and is connected to the surface electrode 3 by a wire.

As shown in FIG. 2, in the divided substrate of the present invention, the end face electrode 2 is formed so as to be embedded at a predetermined length L in the thickness direction from the bottom surface of the insulating base 1 for the divided board. And the side surface of the divided substrate insulating substrate 1 are flush with each other. The length L of the end face electrode 2 in the thickness direction of the divided substrate insulating substrate 1 is equal to 1 of the thickness of the divided substrate insulating substrate 1.
/ 4 or less.

Further, an anchor conductive member 7 formed at a predetermined depth in the thickness direction of the divided substrate insulating substrate 1 is connected to the end face electrode 2. The end face electrode 2 and the anchor conductive member 7 form a T-shape. An electrically conductive member is formed. An end surface electrode 2 and a surface electrode 3 connected to an anchor conductive member 7 are formed on the lower surface of the divided substrate insulating substrate 1.

Further, since the divided substrate is finally mounted by soldering, the end surface electrodes 2 of the divided substrate must be able to be joined by solder. Considering simultaneous firing with ceramics including glass ceramics, ceramics are materials that can be fired at about 800 to 1000 ° C., and the constituent metals of the terminal electrodes are silver, palladium, platinum,
The main component is copper and one of silver and palladium alloys, and among them, a silver alloy or copper is preferable. Since silver is eroded by solder, it is preferable to apply tin plating or the like on a nickel base. Further, since tungsten or molybdenum or the like cannot be directly connected by soldering, it is preferable to apply plating or the like to the surface of tungsten or molybdenum in this case as well.

As shown in FIG. 3, for example, such a divided substrate is disposed on a mother substrate 8 made of a plastic substrate.
Are joined by the solder 9.

In the divided substrate configured as described above, the end surface electrode 2 is formed with a length L in the thickness direction from the bottom surface of the insulating substrate 1 for the divided substrate, and the surface of the end surface electrode 2 and the insulating substrate 1 for the divided substrate are formed. Since the side surfaces are flush with each other, the surface of the end face electrode 2 does not protrude as in the prior art, so that even if an electronic component or the like collides with the end face electrode 2, it does not peel off. Further, the exposed area of the end face electrode 2 can be reduced to a necessary minimum area, and the material cost of the end face electrode 2 and the solder 9 can be reduced.

Further, an anchor conductive member 7 is attached to the end face electrode 2.
Can be further prevented from peeling off the end surface electrode 2 from the insulating substrate for a divided substrate 1, and the internal wiring formed in the insulating substrate for a divided substrate 1 is connected to the anchor conductive member 7, whereby the internal The connection between the wiring and the end face electrode 2 can be reliably performed.

Further, by plating the surface of the end face electrode 2 with a metal having good solder wettability, the end face electrode 2 can be reliably bonded to the mother board 8 even if the exposed area of the end face electrode 2 is small. Furthermore, since no through hole for forming the end face electrode 2 is formed unlike the conventional case, there is no dead space, and the mounting area of components on the divided substrate can be increased.

The divided substrate as described above is obtained by dividing the substrate as shown in FIG. 4 in which the divided substrates are assembled along the dividing groove. Hereinafter, the substrate of the present invention will be described. In FIG. 4, illustration of the surface electrode 3, the chip component 4, and the like is omitted.

As shown in FIG. 5, the substrate of the present invention comprises insulating layers 10a to 10h, internal wiring 11, via-hole conductor 1
2. An insulating substrate 10 is formed by a conductive member 13 serving as an end face electrode 2. The insulating substrate 10 is formed by the insulating layers 10a to 10h, and a surface electrode 3 is formed on the surface.

The insulating layers 10a to 10h are made of, for example, a glass ceramic material, and each has a thickness of 40 to 15 hours.
0 μm. The internal wiring 1 is provided between the insulating layers 10b and 10c and between the insulating layers 10f and 10g.
1 is formed. The internal wiring 11 is made of a gold-based, silver-based, or copper-based metal material, for example, a silver-based conductor. Also,
The internal wires 11 are connected by via-hole conductors 12 penetrating through the thicknesses of the insulating layers 10g and 10h, and are sometimes connected in a distributed manner by capacitive coupling or the like.
This via-hole conductor 12 is also made of a metal such as
It is made of a silver-based or copper-based metal material, for example, a silver-based conductor.

A surface electrode 3 connected to the via-hole conductor 12 is formed on the surface of the insulating substrate 10, and a thick-film resistor film and a thick-film protective film are formed on the surface electrode 3 as necessary. Various types of chip components including ICs are joined by soldering or fine bonding wires, as shown in FIG.

FIGS. 4 to 6 show the insulating substrate 10.
As shown in FIG. 1, a conductive member 13 is formed at a predetermined depth in the thickness direction from the bottom surface of the insulating base 10, and a dividing groove 15 is formed so as to divide the conductive member 13 into two. . The dividing groove 15 is also formed on the upper surface of the insulating base 10 so as to face the dividing groove 15 on the lower surface, and the dividing groove 15 formed on the lower surface is larger than the conductive member 13 in the thickness direction of the insulating base 10. It is deeply formed. FIG. 6 is a bottom perspective view of the vicinity of the conductive member 13 in FIG. 5, and the surface electrode 3 is omitted.

As shown in FIGS. 5 and 6, an anchor conductive member 7 formed at a predetermined depth in the thickness direction from the bottom surface of the insulating base is connected to the conductive member 13 not in contact with the dividing groove 15. Have been. On the lower surface of the insulating base 10, a conductive member 13 and an anchor conductive member 7 are formed in a cross shape. More specifically, a pair of T-shaped conductive members are formed so as to face each other with a dividing groove interposed therebetween. It is.

It is desirable that the length of the conductive member 13 and the anchor conductive member 7 in the thickness direction of the insulating base 10 is not more than ４ of the thickness of the insulating base 10. This requires the formation of the dividing groove 15 in the laminated molded body,
Requires a depth that allows the conductive member 13 to divide the insulating base 10 in the thickness direction. However, if the depth is too deep with respect to the thickness of the insulating substrate 10, the substrate itself is cut. Therefore, the length L of the conductive member 13 in the thickness direction of the insulating base 10 is larger than the surface of the insulating base 10. It is necessary to set the thickness to 10 or less of the thickness of No. 10.

The method of manufacturing a substrate according to the present invention will be described with reference to FIG. First, a slip material to be the insulating layers 10a to 10h is manufactured. The slip material is, for example, glass ceramic or ceramic raw material powder, a photocurable monomer such as polyoxyethylated trimethylolpropane triacrylate, an organic binder such as alkyl methacrylate, and a plasticizer, and an organic solvent such as ethyl carbyl. It is mixed with tall acetate and kneaded with a ball mill.

[0042] As the ceramic raw material powder, for example, at least Mg, Ti, a composite oxide containing Ca, a composition formula by a metal element oxide _{(1-x) MgTiO 3 -xCaTiO} 3 as the metal element ( Here, x represents a weight ratio, and a boron-containing compound is added to B ₂ with respect to 100 parts by weight of a main component represented by 0.01 ≦ x ≦ 0.15).
Those containing ₃ to 30 parts by weight in terms of O ₃ and 1 to 25 parts by weight of an alkali metal-containing compound in terms of alkali metal carbonate are used.

Although the solvent-based slip material is manufactured in the above-described embodiment, a photocurable monomer having a hydrophilic functional group added thereto, for example, a polyfunctional methacrylate monomer,
An aqueous slip material kneaded with ion-exchanged water using an organic binder, for example, a carboxyl-modified alkyl methacrylate, may be used.

Examples of the ceramic raw material powder include glass materials such as SiO ₂ , Al ₂ O ₃ , ZnO, and Mg.
A powder composed of 70% by weight of crystallized glass powder containing O and B ₂ O ₃ as main components and 30% by weight of alumina powder as a ceramic material is also used. The ceramic raw material powder is not particularly limited.

The via-hole conductor 12 and the internal wiring 11
And surface electrode 3, conductive member 13, anchor conductive member 7
A conductive paste is prepared. The conductive paste is
For example, silver powder which is a low melting point and low resistance metal material,
Borosilicate low melting glass, for example, B ₂ O ₃ -SiO ₂ -B
aO _{glass, CaO-B 2 O 3 -SiO} 2 glass, Ca
And _{O-Al 2 O 3 -B 2} O 3 -SiO 2 glass, an organic binder, such as ethyl cellulose, organic solvents, and mixed, for example, 2,2,4-trimethyl-1,3-pentanediol mono-isobutyrate It is manufactured by homogenous kneading with three rollers.

In the method of manufacturing a ceramic circuit board according to the present invention, first, as shown in FIG. 7A, the above-mentioned slip material is applied and dried on a support substrate 25 by a doctor blade method to form an insulating layer 10a. Formed insulating layer 3 for forming
1a is formed. Here, a mylar film is used as the support substrate 25 and is removed before the firing step.

Next, the insulating layer molded body 31a is formed as shown in FIG.
As shown in FIG.
5a (hereinafter, sometimes simply referred to as a through groove 35a) is formed. The formation of the through groove 35a is performed by an exposure process, a development process, and a cleaning / drying process. In the exposure treatment, a photo target is placed on the insulating layer molded body 31a so that the area where the through groove 35a is formed is shielded from light, and for example, an ultra-high pressure mercury lamp (10 mW / cm ² ) is used as a light source. Perform exposure.

As a result, in the insulating layer molded body 31a in the region where the through groove 35a is formed, the photopolymerization reaction of the photocurable monomer does not occur, and the insulating layer molded body other than the region where the through hole HM35a is formed. At 31a, a photopolymerization reaction occurs. Here, the part where the photopolymerization reaction has occurred is called an insolubilized part, and the part where the photopolymerization reaction does not occur is called a solubilized part.

In the developing treatment, the solubilized portion of the insulating layer molded body 31a is removed with a developing solution. Specifically, for example, spray development is performed using a triethanolamine aqueous solution as a developing solution. By this development processing, a cross-shaped through groove 35a can be formed in the insulating layer molded body 31a as shown in FIG. 7B. After that, unnecessary debris and the like generated by developing the insulating layer molded body 31a are completely removed by a washing and drying process.

Next, a conductive paste is filled into the through groove 35a and dried to form a conductive member 13a and a conductive member 36a which becomes a part of the anchor conductive member 7. Specifically, as shown in FIG. 7C, the through-grooves 3 formed in the above-described steps are formed.
5a is filled with the above-mentioned conductive paste and dried. The conductor member 36a is formed by printing using a screen that can be printed only on the portion corresponding to the through groove 35a, and then dried at 80 ° C. for 10 minutes.

By repeating the above-described steps, a laminated body on which the insulating layer molded bodies 31a to 31g are formed is manufactured. After that, apply the slip material by the doctor blade method.
After drying, the insulating layer formed body 31h on the outermost surface of the insulating substrate 10
To form

The above-mentioned exposure treatment is applied to the insulating layer molded body 31h, and a conductive paste is applied to form a surface electrode.

The laminated molded body thus produced is
If necessary, the shape is adjusted by pressing to obtain a laminated molded product as shown in FIG. 7D, and thereafter, the support substrate 25 is removed, and a surface electrode is formed on the bottom surface of the laminated molded product.

Then, a sharp blade is pressed from both sides of the laminated molded body to a position where it is divided into circuit blocks to form a dividing groove as shown in FIG. The dividing groove 15 passes through the center of the conductive member 13. At this time, the depth is a depth at which the conductive member 13 is completely divided. As a result, the T-shaped conductive members face each other.

Thereafter, firing is performed in a debinding step and a main firing step. In the debinding step, the organic binder and the photocurable monomer contained in the binder are eliminated, and sintering is performed in the main firing step.

Thereafter, as a surface treatment, printing and baking of a thick-film resistor film and an insulating film are further performed, plating is performed, and electronic components including an IC chip are joined, whereby a substrate of the present invention is manufactured. You.

[0057]

According to the substrate of the present invention, since the depth of the dividing groove is greater than the depth of the conductive member, the side surface of the conductive member embedded in the substrate is exposed in the dividing groove. Even when the conductive member is divided by the above, the conductive member is not directly divided, the stress is not applied to the conductive member, the peeling of the conductive member from the insulating base is suppressed, and the connection reliability between the conductive member and the insulating base is improved. can do.

Further, in the divided substrate of the present invention, the surface of the end face electrode and the side surface of the insulating substrate for the divided substrate are flush with each other.
The end surface electrode is buried in the insulating substrate for the divided substrate,
Since the surface of the end face electrode does not protrude as in the related art, even if the end face electrode collides with an electronic component or the like, it does not peel off. Further, the exposed area of the end face electrode can be made the minimum necessary area, and the material cost of the end face electrode and solder can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a divided substrate according to the present invention.

FIG. 2 shows the vicinity of an end face electrode of the divided substrate of FIG. 1,
(A) is a sectional view, and (b) is a bottom view.

FIG. 3 is an explanatory view showing a state in which a divided board is mounted on a mother board.

FIG. 4 is a perspective view showing a substrate.

FIG. 5 is a partial cross-sectional view of FIG. 4;

FIG. 6 is a bottom perspective view showing the conductive member of FIG. 5 and its vicinity.

FIG. 7 is a process chart showing a method for manufacturing a substrate.

FIG. 8 is an explanatory view showing a state where a conventional divided board is mounted on a mother board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating base for division | segmentation board 2 ... End surface electrode 7 ... Anchor conductive member 10 ... Insulating base 10a-10h ... Insulating layer 13 ... Conductive member 15 ... Division groove

Claims (3)

[Claims] An insulating base formed by laminating a plurality of insulating layers; a conductive member formed at a predetermined depth in a thickness direction from a surface of the insulating base; and a conductive member formed deeper than the conductive member in a thickness direction of the insulating base. And a dividing groove formed to divide the conductive member into a plurality of parts. 2. A divided substrate comprising: an insulating substrate for a divided substrate formed by laminating a plurality of insulating layers; and an end surface electrode formed on a side surface of the insulating substrate for a divided substrate. A divided substrate formed at a predetermined length in a thickness direction from a surface of the divided substrate insulating substrate, and wherein a surface of the end face electrode and a side surface of the divided substrate insulating substrate are flush with each other. 3. The divided substrate according to claim 2, wherein an anchor conductive member formed at a predetermined depth in a thickness direction of the insulating substrate for the divided substrate is connected to the end face electrode.