JP2000183242A - Junction board and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a junction board and method for manufacturing at a high yield, being easy to form an solder to an electronic component, etc. SOLUTION: A junction board 10 comprises a junction board main body 11, which when provided with first and second main surfaces 11A and 11B, comprises a through-hole 11H penetrating between the two surfaces, a recessed conductor 12 comprising a bottom part 12T which stops the opening on the side of second main surface 11B of the through-hole 11H and a side part 12S covering the inner peripheral surface of the through-hole 11H, and a packing solder body 13, which when packed in a recessed part 12R of the recessed conductor 12, protrudes on the side of first main surface 11A. With a bottomed recessed conductor 12 comprising the bottom part 12T and the side part 12S provided, a part of or all of solder paste which is to be a packing solder body 13 will not fall off in screen printing, etc., enhancing connectivity to the terminal of electric component, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a functional component such as an IC chip, a transistor, a resistor and a capacitor, and a terminal of an electronic component such as a wiring board on which the functional component is mounted, and a mother board and a daughter board for mounting the terminal. More particularly, the present invention relates to a relay board which can be connected to terminals provided at fine intervals, and to a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, when an IC chip is mounted on a printed wiring board as a bare chip, a relay board (interposer) is provided between the IC chip and the printed wiring board in consideration of the difficulty of repair when the IC chip is defective. ) May be interposed. In particular, when mounting a plurality of IC chips on one printed wiring board, connect the plurality of IC chips to the relay board once, confirm that all the IC chips are normal, and then print the relay board. Often connected to a wiring board.

The structure of such a conventional relay board will be described with reference to FIG. In the relay substrate 110 shown in FIG. 11A, a via 112 made of tungsten, molybdenum, or the like is formed in a through hole 111H opened between two main surfaces 111A and 111B of a relay substrate body 111 made of alumina ceramic. Pads 113 and 114 of tungsten, molybdenum, etc. are formed on the main surfaces 111A and 111B so as to cover the upper and lower sides, respectively. As shown in FIG. 11B, electronic components D10 and D20 such as IC chips are interposed with the relay board 110 interposed therebetween.
Is connected to the printed wiring board P10.

The electronic components D10 and D20 are connected to connection surfaces D11 of component bodies D11 and D21 made of silicon, respectively.
B, D21B (lower surface in the figure) have a number of pads D12, D
The pads D12 and D22 are provided with substantially hemispherical solder bumps D13 and D23 made of high-temperature solder (for example, 95Pb-5Sn). The printed wiring board P10 has a connection surface P11A (upper surface in the figure) of a wiring board body P11 made of a glass-epoxy resin composite material.
The pads D12, D22 of the electronic components D10, D20
(Solder bumps D13, D23), and includes a connection pad P12 made of copper and a substantially hemispherical solder bump P13 made of high-temperature solder. These solder bumps D13, D23 and pads 11 of relay board 110
3 and the solder bumps P13 and the pads 114 are soldered with a lower melting point than the high-temperature solder (for example, Pb-S).
n eutectic solder 37Pb-63Sn) Connected by S1 and S2.

FIG. 12 shows another example of the relay board. The relay board 120 has a substantially cylindrical through-hole conductor 122 formed by copper plating in a through hole 121H formed between two main surfaces 121A and 121B of a relay board body 121 made of a glass-epoxy resin composite material.
Are formed, and a plug material 125 made of a conductive resin (or an insulating resin) is filled therein, and pads 123 and 124 are formed in a lid shape by copper plating, respectively. This relay board 120 is also the same as described above (see FIG. 11).
In the same manner as described above, it can be used by connecting to the electronic components D10 and D20 and the printed wiring board P10.

[0006]

However, since the relay board body 111 is made of ceramics such as alumina, the relay board body 110 has a low toughness, and causes problems such as breakage when stress is applied. 111
Cannot be reduced in thickness. On the other hand, if the thickness is large, the length of the via 112 becomes long, so that the resistance and inductance of the via 112 increase, which is not preferable in terms of electrical characteristics. When the thickness is large, the printed wiring board P1
Since the stress due to the difference in thermal expansion from zero increases, the connection reliability between the two also decreases. Further, the relay board 11
0 is, for example, as shown in FIG. 13A, 2 of the ceramic green sheet G that becomes the relay substrate main body 111 after firing.
A conductive paste GP such as a tungsten paste is filled in a through-hole GH penetrating the two main surfaces GA and GB, and a pad (not shown) is printed and fired to form the pad. In this case, if the thickness of the green sheet G is small, the through hole G
Since the ability to hold the conductor paste GP in H is poor,
At the time of printing, a part or almost the entirety of the conductive paste GP once filled is dropped off, which is likely to cause poor filling, and the yield is reduced. Further, if the amount of the conductive paste GP is not constant, unevenness is formed in each pad, coplanarity is reduced, and connectivity with an electronic component D10 such as an IC chip is reduced.

On the other hand, in the above-mentioned relay board 120, migration occurs along the glass fibers included in the relay board main body 121. Therefore, if the distance between the adjacent through holes 121H is reduced, for example, 200 μm or less, Since the reliability under the high-temperature and high-humidity conditions of 120 is reduced, the interval cannot be reduced. Further, when the relay board 120 is filled with the plug material 125 and thermally cured,
As shown in FIG. 13 (b), since the surface 125S has irregularities, the surface 125S is flattened by polishing, and then the pads 123 and 124 are formed. , Polishing becomes difficult. Further, as in the case of the conductive paste GP, when the thickness of the relay board main body 121 is reduced, the plug material (resin) 125 once filled easily falls off. Further, lid-like pads 123, 12 are formed above and below the plug material 125.
4 so that it is polished after the formation of the plug material 125,
Further, since the pads 123 and 124 are formed by plating, the production of the relay board 120 requires many steps and is expensive. Further, in order to connect to the solder bump D13 of the electronic component D10 or the like, a low melting point solder paste is previously applied to the pad 123.
It is necessary to apply heat to the electronic components D10 and the like, and then heat and melt the solder paste to solder.

The present invention has been made in view of the above problems, and has as its object to provide a relay board which has a high yield, is easy to form, and can be easily soldered to electronic parts and the like, and a method of manufacturing the same. I do.

[0009]

Means for Solving the Problems, Action and Effect The solution is to provide a relay board main body having a first main surface and a second main surface and having a through hole penetrating between the two main surfaces. A substantially concave recessed conductor having a bottom portion for closing the opening on the second main surface side of the through hole and a side portion covering the inner peripheral surface of the through hole; And a projecting filling solder body.

According to the present invention, since a bottomed concave conductor having a bottom portion and a side portion is provided, a part or all of the solder paste filled by screen printing or the like in order to form a filled solder body cannot fall off. Since there is no solder, the amount of the filled solder, and therefore the protrusion height, becomes uniform, and the connectivity with terminals such as bumps and pads of an electronic component such as an IC chip increases. Also, since there is no fear of falling off when the solder paste is filled, the thickness of the relay board main body can be reduced. In addition, since the filling solder body protrudes toward the first main surface side, when connecting with a pad or bump of an electronic component to be connected,
Connection can be made securely.

When the filling solder body is made of a material having a melting point lower than that of a bump of an electronic component or the like to be connected on the first main surface side, when the electronic component or the like is connected to the relay board, the bump is not formed. This eliminates the need for an operation such as applying a solder paste having a lower melting point than before.

The main body of the relay board may be appropriately selected in consideration of toughness, insulation, moisture resistance, workability, and the like. For example, resins such as epoxy resin, polyimide resin, BT resin and PPE resin, glass-epoxy resin composite materials, and composite materials of these resins with glass fibers (glass woven fabric or glass non-woven fabric), and these resins and polyamide fibers And a composite material obtained by impregnating a three-dimensional network-like fluororesin such as continuous porous PTFE with an epoxy resin or the like. The concave conductor may be selected in consideration of the material and the like of the relay board main body.
Copper, nickel and the like can be mentioned. Also, the filling solder body is
The material and melting point may be selected in consideration of the material of the electronic component such as an IC chip to be connected or the bump of the printed wiring board. For example, Pb-Sn eutectic solder (37Pb-63S
n) or high-temperature solder (95Pb-5Sn, 90Pb-10)
Sn, etc.) or 96.5Sn-3.5Ag, 95S
n-5Sb solder and the like.

Further, in the above-mentioned relay substrate, it is preferable that the thickness of the relay substrate main body is 200 μm or less.

When the thickness of the relay board is thin, as described above, even if the paste or the like is filled in the through-hole, a problem that the relay board falls off easily occurs. In particular, the thickness of the relay board body is 200 μm or less. In this case, it becomes difficult to hold the conductive paste or the resin paste for the plug material in the through hole.
On the other hand, in the present invention, since the bottomed concave conductor is provided, the paste or the like does not fall off.
Even in the relay substrate body having a thickness of 0 μm or less, it is possible to reliably hold the solder paste and form a filled solder body having a uniform protruding height. Therefore, the resistance and inductance of the concave conductor and the filled solder body can be further reduced. Also, when the thickness is reduced, the shape of the concave conductor becomes relatively shallow, so that the filling of the solder paste into the concave conductor becomes easier. The height can be made more uniform. Furthermore, since the thickness of the relay board main body is thin, even if the electronic components are connected to the printed circuit board with the relay board interposed, the overall height is much higher than when directly connected without the relay board interposed. Does not increase. Therefore, it is possible to meet the demand for a reduction in height.

Further, in the above relay board, it is preferable that a gap between side portions of the adjacent concave conductors is 200 μm or less, and the relay board body is made of a resin-based composite material containing no glass fiber. It is good to use the relay board as a feature.

When a resin-based composite material is used as the material of the relay substrate body, the toughness is higher than when a ceramic such as alumina is used, so that the thickness of the relay substrate body can be reduced. Therefore, the resistance and inductance of the concave conductor and the filled solder body can be further reduced. When the thickness is reduced, the filling of the solder paste into the concave conductor becomes easier, and the volume and the protruding height of the filled solder body can be made more uniform. Further, among the cases where a resin-based composite material is used, those containing glass fibers (for example, a glass-epoxy resin composite material) tend to form a gap between the resin and the glass fibers when forming a through hole, and the like.
Moisture such as a plating solution that has penetrated into the gap causes migration of metal such as copper forming a concave conductor along the surface of the glass fiber, thereby easily causing a short circuit. However, in the present invention, a resin-based composite containing no glass fiber is used. Since the material is used, even if the gap between the side portions of the concave conductor is a short distance of 200 μm or less, no migration occurs and a highly reliable relay substrate can be obtained.

As the resin-based composite material containing no glass fiber, for example, epoxy resin, polyimide resin,
Examples thereof include a composite material of a resin such as a BT resin or a PPE resin and an organic fiber such as a polyamide fiber, and a composite material in which a three-dimensional network-like fluororesin such as continuous porous PTFE is impregnated with an epoxy resin or the like.

Further, the relay board is characterized in that a high-temperature solder bump made of solder having a higher melting point than that of the solder forming the filling solder body is provided on the second main surface side of the bottom of the concave conductor. It is good to use it as a relay board.

In general, even if the solders have different compositions, they are compatible with each other. Therefore, when the solder having a high melting point and the solder having a low melting point come into contact with each other in a molten state, the solder gradually mixes and the composition gradually changes. According to the present invention, since the filled solder body is provided in the concave portion of the concave conductor and the high-temperature solder bump having a higher melting point is provided on the second main surface side at the bottom of the concave conductor, the bump of the IC chip and the like are provided on the first main surface side. Can be connected to a pad of a printed wiring board on which no bump is formed on the second main surface side. Moreover, at this time, the filled solder body and the high-temperature solder bumps are separated at the bottom of the concave conductor.
When forming a high-temperature solder bump or forming a filled solder body, there is no change in composition because they do not mix with each other. That is, the melting point of the filled solder body does not increase or the melting point of the high-temperature solder bump does not decrease. Therefore, even if the solder is heated many times for connection and disconnection for repairing the connected IC chip and the like, the change in the composition and melting point due to the compatibility of both the filled solder body and the high-temperature solder bump on the second principal surface side. Therefore, connection and repair can be repeatedly performed under the same conditions.

When an electronic component such as an IC chip is connected on the first main surface side, the IC chip or the like and the relay substrate of the present invention are integrated into a single substrate having a high-temperature solder bump on the second main surface side. Since it can be handled like an (electronic component), it can be easily connected to a printed wiring board such as a motherboard by using the high-temperature solder bumps.

Still another solution is to provide a relay board body having a first main surface and a second main surface with a through hole penetrating between the two main surfaces and an opening of the through hole on the second main surface side. A through-hole concave conductor forming step of forming a substantially concave concave conductor having a bottom portion to be closed and a side portion covering the inner peripheral surface of the through hole;
A filling solder body forming step of filling a solder paste into the concave portion of the concave conductor from the main surface side and heating to form a filling solder body filled in the concave conductor and protruding toward the first main surface side; A method for manufacturing a relay board, comprising:

According to the present invention, since the through-hole and the concave conductor are formed in the through-hole concave conductor forming step, the solder paste can be reliably filled in the concave portion of the concave conductor in the filling solder body forming step. In addition, since a problem such as a part or all of the solder paste falling off does not occur, the relay substrate can be manufactured with a high yield. Also, the amount of solder in the filling solder body can be made substantially constant,
Since the protruding height can be made uniform, when the first main surface side is connected to an electronic component such as an IC chip, the connectivity can be improved. Further, since the filling solder body protrudes toward the first main surface side, when connecting with a pad or a bump of an electronic component or the like,
Connection can be made securely.

Still another solution is to provide a first main surface and a second main surface.
A main surface of the relay board main body having at least the second main surface side metal layer on the second main surface of the two main surfaces, the second main surface having no metal layer on the first main surface. Second only on surface
At a predetermined position having the main surface side metal layer, the second main surface side metal layer can be pierced and the second main surface side metal layer cannot be pierced by laser processing from the first main surface side using a laser. A through-hole forming step of forming a through-hole in which the second main-surface-side opening is closed by the main-surface-side metal layer, and the through-hole in at least the second main-surface-side opening of the second main-surface-side metal layer; A concave conductor forming step of forming a substantially concave concave conductor by plating an exposed surface exposed inward and an inner peripheral surface in the through hole; and a concave portion of the concave conductor from the first main surface side A filling solder body forming step of forming a filling solder body filled in the concave conductor and protruding toward the first main surface side by heating and filling a solder paste therein. It is a manufacturing method.

According to the present invention, the through-hole is formed in the relay substrate body by laser processing using a laser capable of drilling the relay substrate body and not drilling the second main surface side metal layer. Can be perforated. In addition, since a laser that cannot be perforated is applied to the second main surface side metal layer, the laser is reflected by the second main surface side metal layer, so that a through hole can be formed reliably. Further, since there is no hole in the second main surface side metal layer, it can be used as it is as a base material for forming the bottom in the concave conductor forming step, so that the through hole can easily be formed in the second main surface side opening. , The bottom of the concave conductor can be formed. That is, in the through hole forming step, the second surface side metal layer serves as a laser stopper (and a reflection plate) to contribute to the opening of the through hole, and is formed by plating in the concave conductor forming step. An exposed surface exposed to the through hole can be formed as a base material at the bottom of the concave conductor to be formed.

Further, since a bottomed concave conductor is formed,
In the filling solder body forming step, the solder paste can be reliably filled in the concave portion of the concave conductor, and a problem such as a part or all of the solder paste falling off does not occur. Can be.
In addition, since the amount of solder in the filled solder body can be made substantially constant and the protrusion height can be made uniform, when the first main surface side is connected to an electronic component such as an IC chip, the connectivity can be improved. Further, since the filling solder body protrudes toward the first main surface side, it can be reliably connected to pads, bumps and the like of electronic components and the like.

Further, in the through hole forming step in the method of manufacturing the relay board, the diameter of the second main surface side metal layer that closes the second main surface side opening of the through hole is made larger than the diameter of the second main surface side opening of the through hole. And a method of manufacturing a relay board. In the through hole forming step, if the diameter of the second main surface side metal layer is larger than the diameter of the second main surface side opening of the through hole to be formed, even if there is some displacement in laser processing, The opening can reliably close the second main surface side metal layer.

Further, in the above-described method for manufacturing a relay board, the step of forming the through-hole includes at least one of a first main surface side metal layer having a through hole of a predetermined pattern on the first main surface and the second main surface. A second arrangement located at a position corresponding to the through hole
The relay board main body having a main surface side metal layer,
The relay substrate is characterized by being a conformal mask through-hole forming step of irradiating a laser to the through-hole of the main surface side metal layer wider than the through-hole and forming the through-hole having substantially the same cross section as the through-hole. It is good to use a manufacturing method. According to the present invention, the through-hole is used as a conformal mask, and the laser is irradiated more widely than the through-hole, and the through-hole having substantially the same diameter as the through-hole is formed. it can. Further, it can be formed even if the positioning accuracy of the laser is low.
In addition, when a portion other than the portion where the through hole is formed is covered with the first main surface side metal layer, a plurality of through holes can be formed simultaneously at a time.

[0028]

(Embodiment 1) A first embodiment according to the present invention will be described with reference to the drawings.
FIG. 1A is a plan view of a relay board 10 according to the first embodiment, and FIG. 1B is a partially enlarged cross-sectional view thereof. The relay board main body 11 having a substantially square plate shape in a plan view does not contain glass fibers, and is a resin-resin composite material (thickness: 50 μm) obtained by impregnating and curing continuous porous PTFE with an epoxy resin.
A first main surface 11A and a second main surface 11B, and a diameter of 50 μm penetrating between the two main surfaces.
Are provided. The gap (clearance) between the through holes 11H is 150 μm, which is the smallest.
It has been. In this through hole 11H, a concave conductor 12 made of copper and having a substantially concave shape is formed.
T is arranged so as to close the opening of the through hole 11H on the second main surface 11B side, and the side portion 12S covers the inner peripheral surface of the through hole 11H. Also, in the concave conductor 12 of the present embodiment, the side portion 12S is formed by the first through hole 11H of the first main surface 11A.
The first main surface side opening peripheral portion 12P extends to the main surface side opening peripheral edge 11AP, and the bottom portion 12T extends to the second main surface side opening peripheral edge 11BP of the through hole 11H. An opening peripheral portion 12Q of the second main surface side is formed.

Each of the concave conductors 12 has a concave portion 12 formed by a concave conductor side portion 12S and a bottom portion 12T.
R, that is, the inner peripheral surface 12SH of the concave conductor side portion 12S and the concave portion 12R surrounded by the first main surface side surface (recess bottom surface) 12TA of the bottom portion 12T, and further, the first main surface side opening peripheral portion 12P. The first main surface 11A side (FIG. 1B)
A filling solder body 13 protruding in a substantially spherical shape toward the middle upper side. The filling solder body 13 is made of Pb-Sn eutectic solder (37Pb-63Sn). As will be described later, when connecting bumps or the like of an electronic component such as an IC chip on the first main surface 11A, the filling solder body 13 is used. The solder body 13 is melted and connected to a bump or the like. The through holes 11H, the concave conductors 12, and the filling solder bodies 13 are arranged at positions corresponding to the arrangement of the bumps or the like of the electronic components to be connected. In the present embodiment, they can be easily understood from FIG. The filling solder bodies 13 are separately arranged in four groups, are arranged in a lattice shape in plan view, and connect four electronic components (hereinafter, represented by electronic components D10 and D20). ing.

The relay board 10 is used, for example, as follows. First, as shown in FIG.
Are connected to electronic components D10, D20,... Such as chips. That is, the connection surface of the electronic component bodies D11 and D21 (the lower surface in the figure)
Pads D12, D22 formed on D11B, D21B
High temperature solder bump D13, which is fixed to
D23 is connected by soldering with the filling solder body 13 of the relay board 10. The high-temperature solder bumps D13 and D23 are
For example, since it is made of 95Pb-5Sn, it is heated to a temperature (for example, 230 ° C.) at which only the filled solder body 13 made of Pb-Sn eutectic solder is melted to melt the filled solder body 13, and the high-temperature solder bumps D13 and D23 are formed. The soldering is performed by contacting. At this time, since the filling solder body 13 protrudes toward the first main surface 11A, even if the heights of the high-temperature solder bumps D13 and D23 vary, or if the relay substrate main body 11 is warped or undulated, the filling solder body 13 is not filled. The body 13 and the high-temperature solder bump D13 can be reliably connected.

An electronic component D1 connected to the first main surface side
0, D20, which has a lower melting point than the high-temperature solder bumps D13, D23, specifically, the filled solder body 13 made of Pb-Sn eutectic solder, so that the electronic component D10 and the like and the relay board 10 are connected. In this case, there is no need to apply a solder paste in advance. Since the bottomed concave conductor 12 is disposed in the through hole 11H, as described later, when forming the filling solder body 13,
Since the solder paste filled and applied to the concave portion 12R does not fall off later and the amount of the solder paste can be kept constant, the protruding heights of the filled solder bodies 13 are uniform. Therefore, from this point, the high-temperature solder bump D
Connection with 13 etc. can be reliably performed. Filling solder body 1
(3) Since the molten solder does not spread on the second main surface side (the second main surface side surface 12TB of the bottom portion 12T) even if it is melted, the solder volume of the filling solder body 13 is constant from this point, and the connection is reliably performed. Become.

Thereafter, the connected electronic components D10, D20
Check the operation, etc., remove the defective one, and connect another electronic component again. When all the electronic components operate normally, they are further connected to the printed wiring board P10 as shown in FIG. A substantially hemispherical high-temperature solder bump P13 fixed to a pad P12 formed on a connection surface (upper surface in the drawing) P11A of the printed wiring board main body P11 is provided on a bottom portion 12T of the concave conductor 12 of the relay substrate 10 by Pb-Sn eutectic solder. Solder connection by SL. Specifically, a Pb-Sn eutectic solder paste (not shown) was previously applied to the bottom 12T of the concave conductor 12 or to the high-temperature solder bump P13, and the electronic components D10 and D20 were mounted on the printed wiring board P10. The relay substrate 10 is stacked and heated in a reflow furnace to melt the Pb-Sn eutectic solder paste, and the concave conductor 12 and the high-temperature solder bump P13 are connected by soldering. This means that each of the electronic components D10, D20,... Has been connected to the printed wiring board P10 via the relay board 10.

In this manner, the electronic components D10, D20
The relay board 10 that connects the printed wiring board P10 to the
For example, since a resin-resin composite material obtained by impregnating and curing an epoxy resin in continuous porous PTFE as described above is not a composite material containing glass fibers as in a glass-epoxy resin composite material, it has high moisture resistance and migration. Is unlikely to occur. Therefore, as in the present embodiment, the through holes 11
Even when the gap between H is 150 μm at the minimum, no short circuit or the like due to migration occurs.

Comparative Examples 1 and 2 On the other hand, in Comparative Examples 1 and 2, a material containing glass fiber was used as the material of the relay substrate body, specifically, BT (bismaleimide-triazine) resin was used in a glass fiber woven fabric. Using a glass-BT resin composite material with a thickness of 200 μm impregnated, each via diameter (diameter of through hole)
300 μm, minimum gap between vias 200 μm and 40 μm
A conventional relay board having a thickness of 0 μm (see FIG. 12) was manufactured.

(Embodiment 1B) Further, as Embodiment 1B, the relay board 10 is made of the same material as that of Embodiment 1 described above, but the thickness of the relay board body is set to 200 μm, which is four times thicker, and the concave conductor diameter (through hole diameter) ) 50 μm is similar,
The minimum gap between the concave conductor sides is 50μm larger, 200μ
A relay board having a length of m was also manufactured.

(Test Example) A wet / medium load test was performed using the relay boards 10 and the like according to Embodiments 1 and 1B and Comparative Embodiments 1 and 2 to determine whether insulation resistance was reduced due to migration. Specifically, a temperature of 85 ° C. and a humidity of 8
In a thermo-hygrostat set at 5% RH and atmospheric pressure, a voltage of 50 V DC was applied between the vias of each relay substrate and held, and the insulation resistance between the vias (5 V × 60 seconds) was measured at appropriate times. ,
The period during which the insulation resistance of 100 MΩ or more could be maintained was measured. Table 1 shows the results.

[0037]

[Table 1]

As can be seen from Table 1, in Comparative Example 2 in which the minimum gap between vias is 400 μm, an insulation resistance of 100 MΩ or more is maintained for 1000 hours or more, whereas in Comparative Example 1, 500 hours is required. Insulation resistance is 100M
Ω or less. Specifically, copper migration occurred along the glass fibers of the relay substrate body, and an electrical path was formed between the vias. For this reason, when a resin-based composite material containing glass fibers, more specifically, a glass-BT resin composite material is used, the gap between the vias may be maintained at about 400 μm.
Under the following conditions, it is found that migration occurs, so that the reliability of the relay board is significantly reduced.

On the other hand, in each of Embodiments 1 and 1B, an insulation resistance of 100 MΩ or more is maintained for 1000 hours or more. In these embodiments, the material of the relay board main body 11 and the like is a resin-based composite material containing no glass fiber, specifically, a composite material in which a three-dimensional mesh-like fluororesin is impregnated with an epoxy resin or the like, and more specifically. Typically, continuous porous P
A resin-resin composite material in which TFE was impregnated with an epoxy resin and cured was used. Therefore, the gap between the concave conductors is 2
00 μm or less, specifically 200 μm (Embodiment 1)
B), it is considered that no migration occurred even with 150 μm (Embodiment 1). Accordingly, a resin-based composite material containing no glass fiber, specifically, a resin obtained by impregnating a continuous porous PTFE with an epoxy resin-
When the resin composite material is used for the relay substrate body, the gap between the side portions of the concave conductor is set to 200 μm or less, and
It can be seen that even if it is less than μm, migration does not occur, and a relay substrate having high reliability can be obtained.

Next, a method of manufacturing the relay board 10 will be described with reference to FIGS. First, FIG.
(A) As shown in FIG.
A relay board main body 11, which is made of a composite material in which E is impregnated with an epoxy resin and cured, has a first main surface 11A and a second main surface 11B and has a substantially plate shape, is prepared. This relay board body 1
A 12 μm thick copper foil 14 having a through hole 14H having a diameter of 50 μm at a predetermined position on the first main surface 11A, and a 12 μm thick copper foil 15 on almost the entire surface of the second main surface 11B. Is attached.

Next, the third harmonic (355 nm) of the YAG laser is irradiated from the first main surface 11A side over a wider range than the through hole 14H, and the through hole 14H is used as a mask pattern. As shown, the relay board body 1
A plurality of through holes 11H having substantially the same cross section as the through holes 14H are formed at one time. Since this laser light is reflected by the copper foil 14, the laser processing is performed only in the through hole 14H where the copper foil 14 is not provided. That is, the copper foil 14 becomes a conformal mask in the conformal mask method. Further, since the copper foil 15 also reflects this laser beam, no through-hole (through-hole) is formed in the copper foil 15, so that the through-hole 11 </ b> H is closed by the copper foil 15. Further, since the laser light is reflected by the copper foil 15, the incident light and the reflected light cause
H is reliably formed. Thereby, in this embodiment,
A large number of through holes 11H having a diameter of 50 μm and a minimum gap of 150 μm were formed.

Thereafter, the surface of the copper foil 14 (upper surface in the drawing), the surface of the copper foil 15 (lower surface in the drawing), the exposed surface of the copper foil 15 in the through hole 14H (the upper surface in the drawing), and the inner peripheral surface of the through hole 11H. Is subjected to electroless copper plating to form an electroless copper plating layer 1 having a thickness of 1 μm.
6 and 17 are formed (see FIG. 3C). Further, a photosensitive plating resist film is applied to the electroless plating layer 1.
6, 17 and then exposed and developed to form a through hole 11H.
The inside and the electroless plating layer 16 on the first main surface side opening edge (diameter 120 μm) and the electroless plating layer 17 on the second main surface side of the through hole 11H and the opening edge (diameter 120 μm) are exposed. Plating resist layers MR1 and MR2 having through holes MR1H and MR2H are formed. Next, electrolytic copper plating is performed using the electroless copper plating layers 16 and 17 as a common electrode, and a substantially concave-shaped 6 μm-thick film is formed on the electroless plating layer 16 in the through hole 11H and the periphery of the opening on the first main surface side. An electrolytic copper plating layer 18 is formed, and an electrolytic copper plating layer 19 having the same thickness is formed on the second principal surface side of the through hole 11H and the electroless plating layer 17 on the periphery of the opening (see FIG. 3D). .

Thereafter, the plating resists MR1 and MR2 are dissolved and removed (see FIG. 3E), and the exposed electroless copper plating layers 16 and 17 and the copper foils 14 and 15 located thereunder are exposed.
Is removed by etching to obtain FIG.
As shown in (1), a substantially concave concave conductor 12 is formed in the through hole 11H and on the periphery thereof. The concave conductor 12 has a bottom portion 12T covering the through hole 11H, and a side portion 12S covering the inner peripheral surface of the through hole 11H to form a concave portion 12R. Further, as shown in FIG. 4B, the concave portion 12 is formed by using a mask M having a through hole MH corresponding to the position of the through hole 11H.
Rb and Pb- on the first main surface 11A side (upper side in the figure).
Fill and apply Sn eutectic solder paste SP. At this time, since the through-hole 11H is closed by the bottom 12T of the concave conductor 12 and becomes a bottomed (blind hole) state, the Pb-Sn eutectic solder paste SP filled in the concave 12R is replaced with a conventional one. (See FIG. 13 (a)).
Filling can be performed with good yield. Thereafter, by heating through a reflow furnace, the Pb-Sn eutectic solder paste is melted to form a filled solder body 13, and the relay board 10 is completed (see FIG. 1). In this relay board 10, since the solder volume of the filling solder body 13 is substantially constant, the protruding height of the filling solder body 13 is also substantially constant. In this embodiment, since the copper foil 14 is used as a conformal mask, it is advantageous in that it is not necessary to increase the irradiation position accuracy of the laser beam. In addition, since the first main surface 11A is covered with the copper foil 14 except for the through holes 14H, it is advantageous in that a plurality of through holes 11H can be formed at once.

(Embodiment 2) Next, a second embodiment will be described with reference to FIG. The relay board 20 according to the first embodiment can be easily understood from the partial enlarged cross-sectional view shown in FIG.
, But the second main surface side surface 12TB of the bottom portion 12T.
And a high-temperature solder bump 23 which is substantially hemispherically raised. Therefore, in the following, description of similar parts will be omitted or simplified, and different parts will be described. The high-temperature solder bumps 23 of the relay board 20 of the present embodiment are made of 90Pb-10Sn,
Is welded to the second main surface side surface 12TB and has a substantially hemispherical shape. As described above, such high-temperature solder bumps 23 are not melted by heating (about 230 ° C.) enough to melt Pb—Sn eutectic solder, for example. Electronic component D1 on the same side
0, D20, etc.

On the other hand, when connecting to the printed wiring board P10, unlike the first embodiment,
It is not necessary to previously form the high-temperature solder bump P13 on the pad P12. That is, the high-temperature solder bump 23 can be used to connect to the pad P12 without the high-temperature solder bump P13 (not shown), similarly to the case where the electronic component D10 or the like is directly connected to the pad P12 without the intervention of the relay board 20. Specifically, the high-temperature solder bumps 23,
Alternatively, a Pb-Sn eutectic solder paste is applied on the pads 12, and the printed wiring board P10 (without the high-temperature solder bumps P13) and the relay board 20 are stacked and heated.
The Pb-Sn eutectic solder paste is melted and connected.
Therefore, if the relay board 20 is used, it is not necessary to previously form the high-temperature solder bumps P13 on the printed board P10.

Next, a method of manufacturing the relay board 20 will be described. Among them, the concave conductor 1 shown in FIG.
2 is the same as that of the first embodiment. Thereafter, as shown in FIG. 5B, a mask M2 having a through-hole M2H at a position corresponding to the second main surface side surface 12TB is prepared, and this is overlaid on the second main surface 11B side of the relay substrate main body 11. After the alignment, the high-temperature solder paste SP of 90Pb-10Sn is formed on the second main surface side surface 12TB (upper in FIG. 5B).
2 is applied. Thereafter, the solder paste is heated to about 330 ° C. to melt the high-temperature solder paste SP2, thereby forming a substantially hemispherical high-temperature solder bump 23 on the second main surface side surface 12TB. Thereafter, as in the first embodiment, Pb-S is formed in the recess 12R.
The n-eutectic solder paste SP is filled (see FIG. 4 (b)), and this is heated and melted to form the filled solder body 13 and complete the relay board 20.

(Embodiment 3) A third embodiment, which is substantially the same as the relay board 10 of the first embodiment but formed by a different manufacturing method, will be described. The relay board main body 31 used in this manufacturing method (FIG. 6)
(See (a)) is a composite material in which continuous porous PTFE is impregnated with an epoxy resin and cured by a thickness of 50 μm, similarly to the first embodiment, and has a first main surface 31A and a second main surface 31B.
And has a substantially plate shape. However, this relay board body 31
Has no copper foil on the first main surface 31A side and has a second main surface 31A.
On the B side, a circular copper foil 35 having a diameter of 120 μm is provided at a predetermined position.
Is attached. The first main surface 3 of the relay board main body 31
The third harmonic of the YAG laser is irradiated from the 1A side. However, the spot diameter of the laser beam is reduced, and the laser beam is radiated to a predetermined position, specifically, substantially at the center of the circular copper foil 35, as shown in FIG.
As shown in (b), a through hole 31H having a diameter of 50 μm smaller than the diameter (120 μm) of the copper foil 35 is formed. At this time, the through hole 31H is formed so as to be included in the inside of the copper foil 35 in plan view. In the laser processing, the copper foil 3
No. 5 is not perforated as in the case of the first embodiment.

Next, the surface (lower surface in the drawing) of the copper foil 35, the exposed surface (upper surface in the drawing) and the inner peripheral surface of the through hole 31H of the copper foil 35, and the first and second main surfaces 31A and 31B Then, electroless copper plating is performed to form electroless copper plating layers 36 and 37 having a thickness of 1 μm (see FIG. 6C). Further, a photosensitive plating resist film is applied to the electroless plating layers 36 and 3.
7 and exposed and developed to expose the electroless plating layer 36 in the through hole 31H and the periphery of the first main surface side opening (diameter 120 μm) and the electroless plating layer 37 on the copper foil 35. Thus, plating resist layers MR3 and MR4 are formed. Next, electrolytic copper plating is performed using the electroless copper plating layers 36 and 37 as a common electrode, and a substantially concave-shaped 6 μm thick film is formed in the through-hole 31H and on the electroless plating layer 36 around the opening on the first principal surface side. The electrolytic copper plating layer 38 is also
An electrolytic copper plating layer 39 of the same thickness is formed on the second main surface side of 1H and the periphery of the opening, that is, on the electroless plating layer 37 on the copper foil 35 (downward in the figure) (see FIG. 6D). ).

Thereafter, the plating resists MR3 and MR4 are dissolved and removed, and the exposed electroless copper plating layers 36 and 37 are removed by etching, so that the inside of the through-hole 31H and its periphery are removed as shown in FIG. A concave conductor 32 having a substantially concave shape is formed. The recessed conductor 32 closes the through hole 31H at the bottom 32T and covers the inner peripheral surface of the through hole 31H at the side 32S, similarly to the relay board 10 described above.
2R. Also, the side portion 32S of the concave conductor 32
Extends to the first main surface side opening periphery of the through hole 31H in the first main surface 31A to form the first main surface side opening peripheral portion 32P, and the bottom portion 32T is formed of the through hole 31H. The second main surface side opening peripheral portion 32Q is extended to the second main surface side opening peripheral portion.
After that, the Pb-Sn eutectic solder paste SP is filled in the recess 32R using the mask M as in the first embodiment (see FIG. 4B), and is melted by heating.
The filling solder body 33 is formed. As a result, FIG.
As shown in (1), a relay board 30 substantially similar to the relay board 10 of the first embodiment is completed.

In this relay board 30, Pb-Sn
When filling and applying the eutectic solder paste SP, the through-hole 31H is closed by the bottom 32T of the concave conductor 32 and becomes a bottomed (blind hole) state. The Sn eutectic solder paste SP does not fall off as in the conventional case (see FIG. 13A). Therefore, also in the relay substrate 30, the solder volume of the filling solder body 33 is substantially constant, and the protruding height of the filling solder body 33 can be substantially constant. In the relay substrate 30, in etching after the removal of the plating resists MR3 and MR4, only the thin electroless plating layers 36 and 37 need to be removed by etching, so that the etching is performed by soft etching without using a strong chemical. This is excellent because etching and subsequent processing are easy. Further, since there is no need to form a copper foil corresponding to the copper foil 14 in the first embodiment on the first main surface 31A, the cost is reduced accordingly.

(Embodiment 4) Further, as a fourth embodiment, a manufacturing method which is substantially the same as the relay boards 10 and 30 of the above-described first and third embodiments, but is different therefrom will be described. The relay board main body 41 used in this manufacturing method (FIG. 8)
(See (a)) is the same as in the first and third embodiments.
m and a composite material in which continuous porous PTFE is impregnated with an epoxy resin and cured, and has a first main surface 41A and a second main surface 4A.
1B and a substantially plate shape. However, this relay board body 4
1 has an outer diameter of 120 μm at a predetermined position on the first main surface 41A side.
m, a ring-shaped copper foil 44 having an inner diameter of 50 μm
On the main surface 41B side, a position corresponding to the ring-shaped copper foil 44,
That is, a circular copper foil 45 having a diameter of 120 μm is attached at a position that is concentric in plan view. The first of the relay board main body 41
The third harmonic of the YAG laser is irradiated from the main surface 41A side. However, the spot diameter of the laser beam is reduced to approximately 80 μm,
As shown in FIG.
As shown in (b), a through-hole 41H having a cross-sectional shape (diameter: 50 μm) according to the inner diameter of the ring-shaped copper foil 44 is formed.
In the laser processing according to the present embodiment, the copper foils 44 and 45 are not perforated as in the case of the first embodiment. Further, as can be easily understood, the ring-shaped copper foil 34 functions as a conformal mask using the inner diameter as a mask pattern.

Next, the surface of the copper foil 44 (upper surface in the drawing), the surface of the copper foil 45 (lower surface in the drawing), the exposed surface (upper surface in the drawing) of the copper foil 45 and the inner peripheral surface of the through hole 41H, Electroless copper plating is performed on the first and second main surfaces 41A and 41B,
Electroless copper plating layers 46 and 47 having a thickness of 1 μm are formed (see FIG. 9A). Further, a photosensitive plating resist film is stuck on the electroless plating layers 46 and 47, and exposed and developed, so that the inside of the through-hole 41H and the copper foil 44, that is, the inside of the through-hole 41H and the periphery of the opening on the first main surface side. (120μ diameter
m) through holes MR5H and MR6H so that the electroless plating layer 46 and the electroless plating layer 47 on the copper foil 45 are exposed.
The plating resist layers MR5 and MR6 having the following are formed.
Next, electrolytic copper plating is performed using the electroless copper plating layers 46 and 47 as a common electrode, and a substantially concave-shaped 6 μm thick film is formed on the electroless plating layer 46 in the through hole 41H and the periphery of the opening on the first main surface side. The electrolytic copper plating layer 48 is provided with the through hole 41H.
An electrolytic copper plating layer 49 having the same thickness is formed on the second principal surface side and the periphery of the opening, that is, on the electroless plating layer 47 on the copper foil 45 (the lower part in the figure) (see FIG. 9B).

After that, the plating resists MR5 and MR6 are dissolved and removed (see FIG. 9C). Thereafter, the exposed electroless copper plating layers 46 and 47 are removed by etching, so that the through holes 41 are formed as shown in FIG.
A substantially concave concave conductor 42 is formed in H. The concave conductor 42 has a bottom 42T similar to the relay substrate 10.
Closes the through hole 41H, and the side portion 42S covers the inner peripheral surface of the through hole 41H to form a concave portion 42R. Further, the side portion 42S of the concave conductor 42 is connected to the through hole 41 of the first main surface 41A.
H extends to the first main surface side opening peripheral edge to form a first main surface side opening peripheral portion 42P, and the bottom portion 42T extends to the second main surface side opening peripheral edge of the through hole 41H. After forming the second main surface side opening peripheral portion 42Q, the first embodiment
Similarly, using the mask M, the Pb-Sn
Fill eutectic solder paste SP (see FIG. 4 (b)),
By heating and melting, a filled solder body 43 is formed. Thereby, as shown in FIG. 10B, a relay board 40 substantially similar to the relay board 10 of the first embodiment is completed.

Also in this relay board 40, the relay board 1
0,30, Pb-Sn eutectic solder paste SP
When filling and applying, the through-hole 41H is
Of the Pb-Sn eutectic solder paste SP filled in the concave portions 42R as in the conventional case (see FIG. 13A). Never do. Therefore, also in the relay board 40, since the solder volume of the filling solder body 43 is substantially constant, the protrusion height of the filling solder body 33 can be substantially constant. In the relay board 40, as in the relay board 30,
In the etching after the removal of the plating resists MR5 and MR6, only the thin electroless plating layers 46 and 47 need to be etched and removed. Therefore, the etching may be performed by soft etching without using a strong chemical. This is excellent in that the treatment is easy. Further, since the through-hole 41H is formed by the conformal mask method using the ring-shaped copper foil 44, it is excellent in that it is not necessary to make the irradiation position accuracy of the laser beam very high.

In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. Nor. For example, in the above-described embodiment, each of the periphery 11AP such as the through-hole 11H,
Although the conductor layer 12 and the like are also spread on 11BP to form the first and second principal surface side opening peripheral portions 12P and 12Q, FIG.
These may not be formed. Further, the conductor layer 12 and the like are all made of copper foil and copper plating, but other metals such as nickel or the like, or
It may be made of two or more kinds of metals, for example, nickel plating on a copper foil or a copper plating layer. In the above-described embodiment, the filling solder body 13 has a spherical projection on the first main surface 1A side. However, the projection height of each filling solder body is a flat plate that does not wet with solder such as ceramic or stainless steel when molten. It is preferable to regulate the height and cool as it is so that the top of the first main surface side of each filling solder body 13 becomes flat. By flattening according to the plane of the flat plate, the coplanarity of each filled solder body can be reduced, and when the filled solder body is melted again for connection with solder bumps, the height of the top is reduced. This is because the connection with the solder bump can be reliably performed because the height is high.
In order to flatten the tops of the filled solder bodies, each of the filled solder bodies 13 and the like that have been melted and solidified may be pressed by a flat mold to flatten the tops. Further, in each of the above embodiments, the concave conductor 12 and the like are formed using electroless plating and electrolytic plating, but the concave conductor may be formed only by electroless plating.

[Brief description of the drawings]

FIG. 1 is a plan view (a) and a partially enlarged cross-sectional view (b) of a relay board according to a first embodiment.

2A is an explanatory view showing a state in which an IC chip is connected to the relay board of FIG. 1, and FIG. 2B is an explanatory view showing a state in which a printed wiring board is further connected.

FIG. 3 is an explanatory view showing a process until a plating resist is removed in the method of manufacturing the relay board according to the first embodiment.

FIG. 4 is an explanatory diagram showing a process of filling a recess conductor with a solder paste in the method of manufacturing the relay board according to the first embodiment.

FIG. 5A is a partially enlarged cross-sectional view of a relay board according to a second embodiment, and FIG. 5B is an explanatory view showing a step of applying a high-temperature solder paste to the bottom side of the concave conductor in the method of manufacturing the relay board; It is.

FIG. 6 is an explanatory view showing steps up to electrolytic plating in the method of manufacturing the relay board according to the third embodiment.

FIG. 7A is an explanatory view showing an etching step in the method for manufacturing a relay board according to the third embodiment, and FIG. 7B is a partially enlarged cross-sectional view of the relay board according to the third embodiment.

FIG. 8 is an explanatory view showing steps up to the formation of a through-hole in the method of manufacturing the relay board according to the fourth embodiment.

FIG. 9 is an explanatory view showing steps up to removal of a resist in the method of manufacturing the relay board according to the fourth embodiment.

FIG. 10A is an explanatory view showing an etching step in the method for manufacturing a relay board according to the fourth embodiment, and FIG.
FIG. 4 is a partially enlarged cross-sectional view of the relay board according to FIG.

FIG. 11A is a partially enlarged cross-sectional view of a conventional relay board,
(B) is an explanatory view showing a state in which an IC chip and a printed wiring board are connected above and below the conventional relay board.

FIG. 12 is a partial cross-sectional view of a conventional relay board different from FIG. 11 (a).

FIG. 13A is an explanatory view illustrating a state in which a paste filled in a through-hole falls off, and FIG. 13B is a view showing a paste (resin) obtained by curing the paste filled in the through-hole.
FIG. 4 is an explanatory view showing a state in which irregularities are formed in FIG.

[Explanation of symbols]

 10, 20, 30, 40 Relay board 11, 31, 41 Relay board body 11A, 31A, 41A First main surface 11B, 31B, 41B Second main surface 11H, 31H, 41H Through hole 12, 32, 42 Concave conductor 12T , 32T, 42T Bottom 12S, 32S, 42S (of concave conductor) Side 12R, 32R, 42R (of concave conductor) Recess 13, 33, 43 Filled solder body 23 Solder bump

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Naru Hirano 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi Inside Japan Specialty Ceramics Co., Ltd. (72) Inventor Yasuhiro Sugimoto 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi Japan Special Ceramics F term in the company (reference) 5E319 AA10 BB05 CC22 CD26 5E336 BC25 DD04 EE01 5E344 BB02 CC05 DD02 EE06

Claims (8)

[Claims] 1. A relay board main body having a first main surface and a second main surface and having a through hole penetrating between the two main surfaces, a bottom portion closing an opening of the through hole on the second main surface side. A concave conductor having a substantially concave shape having a side portion covering the inner peripheral surface of the through hole, and a filling solder body filled in a concave portion of the concave conductor and protruding toward the first main surface side. Relay board. 2. The relay board according to claim 1, wherein the thickness of the relay board body is 200 μm or less. 3. The relay board according to claim 1, wherein the gap between the side portions of the adjacent concave conductors is 200 μm.
The relay substrate according to claim 1, wherein the relay substrate body is made of a resin-based composite material that does not include glass fibers. 4. The relay board according to claim 1, wherein a solder having a higher melting point than the solder forming the filling solder body is provided on the second main surface side of the bottom of the concave conductor. A relay board comprising high-temperature solder bumps. 5. A relay board body having a first main surface and a second main surface, a through-hole penetrating between the two main surfaces, a bottom for closing an opening of the through-hole on the second main surface, and the through-hole. A through-hole concave conductor forming step of forming a substantially concave concave conductor having a side portion covering an inner peripheral surface of the hole; and filling and heating a solder paste into the concave portion of the concave conductor from the first main surface side. A filling solder body forming step of forming a filling solder body that fills the concave conductor and protrudes toward the first main surface side. 6. A relay board main body having a first main surface and a second main surface, wherein at least the second main surface of the two main surfaces has a second main surface side metal layer. At a predetermined position where the main surface has no metal layer and only the second main surface has the second main surface side metal layer, a laser capable of piercing the relay board main body and not piercing the second main surface side metal layer is used. A step of forming a through-hole in which the second main-surface-side metal layer closes the second main-surface-side opening by laser processing from the first main-surface side used; A concave portion that forms a substantially concave concave conductor by plating the exposed surface of the surface-side metal layer that is exposed toward the inside of the through hole and the inner peripheral surface of the through hole in the second main surface side opening. A step of forming a conductor, filling a solder paste into the concave portion of the concave conductor from the first main surface side and heating the solder paste; Method for producing a relay board to the filling solder forming step, characterized in that it comprises a to be filled in the Jo conductor to form a filled solder body projecting to the first main surface side. 7. The method of manufacturing a relay board according to claim 6, wherein a diameter of the second main surface side metal layer closing the through hole is larger than a diameter of the second main surface side opening of the through hole. A method for manufacturing a relay board, comprising: 8. The method for manufacturing a relay board according to claim 6, wherein the through hole forming step includes: forming a first main surface side metal layer having a predetermined pattern of through holes on the first main surface; The relay board main body having at least a second main surface side metal layer disposed at a position corresponding to the through hole in the second main surface is provided with the through hole in the first main surface side metal layer. A method of manufacturing a relay board, comprising a step of forming a conformal mask through-hole in which a laser is irradiated wider than the hole to form the through-hole having substantially the same cross section as the through-hole.