JP2003046030A - Wiring board with pin, and electronic device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board with pins, where loaded electronic components can normally be connected to an outer electric circuit the load pins of which will not come off easily, and to provide an electronic device. SOLUTION: In the wiring board with pins, pads having pins 2b, which are electrically connected to wiring conductors 2 are arranged at the lower face of the insulation board 1 of an organic material system, having the wiring conductors 2. The lead pins 3, in which almost disk-like large diameter parts 3b are formed at the upper ends of the cylindrical shaft parts 3a and are constituted of copper alloy, are erected on the pads with pins 2b, by making solder 9 interpose in between the large diameter parts 3b and the pads with pins 2b. In the lead pins 3, elastic modulus is 90 to 120 GPa, and in addition Vickers hardness is 110 to 160 Hv.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board with pins used for mounting electronic parts such as semiconductor elements, and an electronic device having the electronic parts such as semiconductor elements mounted on the wiring board with pins. It is a thing.

[0002]

2. Description of the Related Art Recently, as a wiring board with a pin used for mounting electronic parts such as semiconductor elements, for example, a plurality of insulating layers made of glass-epoxy board or insulating layers made of epoxy resin are laminated. A plurality of wiring conductors made of copper foil or the like are provided from the upper surface to the lower surface of the insulating substrate made of, and a plurality of pin-bonding pads are formed at the portions of these wiring conductors led to the lower surface of the insulating substrate, and these pin-bonding pads are The lead pin is formed by arranging the disk-shaped large-diameter portion having a diameter of about 1.5 times the diameter of this shaft-shaped portion on the upper end of the cylindrical shaft portion by abutting the large-diameter portion and soldering. Wiring boards with pins made of organic materials have been adopted. Such an organic-material-based wiring board with pins has the advantages that it is lighter in weight than the ceramic-material-based wiring board and that the electrical resistance of the wiring conductor is small. In such an organic material-based wiring board with pins, electronic components are mounted on the upper surface of the insulating substrate, and electrodes of the electronic components and wiring conductors are electrically connected via solder bumps or bonding wires. By sealing the electronic component with a lid member made of metal or ceramic or a sealing member made of potting resin, an electronic device as a product is obtained. In this electronic device, the lead pins on the lower surface of the insulating substrate are connected to the external electric circuit board. By connecting to the wiring conductor via a socket, solder, or the like, the electronic component mounted and mounted on the external electric circuit board is electrically connected to the external electric circuit.

As lead pins in such a wiring board, lead pins made of a copper alloy having a thermal expansion coefficient close to that of an insulating base made of resin have come to be used, and a lead pin and a pin pad are used. As the solder to be soldered, the stress from the external lead pins is soldered through the solder when external force is applied to the external lead pins in order to prevent the resin insulating base from being damaged by heat during soldering. In order to prevent the soldering pad from being peeled off due to a large voltage applied to the pad, for example, a lead-tin-antimony alloy or the like has a melting point of 270 ° C. or less and an elastic modulus of 50 GPa.
The following solders are being used.

[0004]

However, according to the conventional wiring board with a pin made of an organic material and the electronic device using the same, the lead pin made of a copper alloy is usually workable when it is manufactured. Heat treatment at a temperature of about 700 ° C to improve the heat resistance, resulting in an elastic modulus of about 80 GPa and a Vickers hardness of about 80H.
The lead-tin-which joins the lead pin and the pin-bonding pad with the lead-tin-
Since the yield stress of solder made of antimony alloy or the like is small, if the lead pin is pulled vertically or obliquely with a force of about 30 N, the large diameter portion of the lead pin is excessively elastically and plastically deformed by the force, As a result, a large amount of stress concentrates and acts on the surface and a part of the inside of the solder made of lead-tin-antimony alloy or the like that joins the lead pin and the pin-attaching pad through the large diameter portion of the lead pin, and as a result, yielding occurs. Breakage occurs in solder with low stress and lead pins are removed from the insulating substrate.If the lead pins are removed from the insulating substrate in this way, the mounted electronic components cannot be normally connected to the external electric circuit. Had the problem.

The present invention has been completed in view of the above conventional problems, and an object thereof is to prevent the lead pin from being removed even if the lead pin is pulled with a force of about 50 N, and to mount an electronic component mounted on an external electric circuit. An object of the present invention is to provide a highly reliable wiring board with a pin and an electronic device that can be normally connected to the wiring board.

[0006]

A wiring board with pins according to the present invention is provided with pinning pads electrically connected to wiring conductors on the lower surface of an insulating substrate made of an organic material having wiring conductors, and the pinning is performed. Wiring with pins in which a lead pin formed by forming a substantially disk-shaped large-diameter portion on the upper end of a substantially cylindrical shaft portion on a pad is erected with solder interposed between the large-diameter portion and the pin-attaching pad The substrate is characterized in that the lead pin has an elastic modulus of 90 to 120 GPa and a Vickers hardness of 110 to 160 Hv.

In the electronic device of the present invention, a pin pad electrically connected to the wiring conductor is provided on the lower surface of the insulating substrate made of an organic material having a wiring conductor, and the pin pad has a substantially cylindrical shape. An electronic component is mounted on a wiring board with a pin, in which a lead pin formed by providing a substantially disk-shaped large-diameter portion at the upper end of a shaft portion is erected with a solder interposed between the large-diameter portion and a pin attachment pad. At the same time, an electronic device electrically connecting an electrode of an electronic component and a wiring conductor, wherein the lead pin has an elastic modulus of 90 to 120 GPa and a Vickers hardness of 110 to 160 Hv. It is a feature.

According to the wiring board with a pin of the present invention and the electronic device using the same, the lead pin made of a copper alloy is
Since its elastic modulus is 90-120 GPa and its Vickers hardness is 110-160 Hv, the large diameter portion will not be excessively elastically or plastically deformed when a force for pulling it is applied to the lead pin. Since it is elastically and plastically deformed moderately, the stress caused by the pulling force of the lead pin is well dispersed due to the elastic and plastic deformation of the large diameter part of the lead pin, and the stress is largely concentrated on the solder surface and a part of the inside. Can effectively be prevented.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment in which the present invention is applied to a wiring board with pins for mounting a semiconductor element and an electronic device mounting a semiconductor element on the wiring board. 2 is a wiring conductor, 3
Is a lead pin. The insulating substrate 1, the wiring conductor 2, and the lead pin 3 constitute the wiring substrate with pins of the present invention.
The electronic device of the present invention is formed by mounting the semiconductor element 4 as an electronic component on this.

The insulating substrate 1 is formed by impregnating a glass woven fabric in which glass fibers are woven vertically and horizontally with a thermosetting resin such as epoxy resin or bismaleimide triazine resin. It is an organic material-based multi-layered plate formed by laminating a plurality of insulating layers 1b each made of a thermosetting resin such as a bismaleimide triazine resin. The wiring conductor 2 is formed.

The core 1a constituting the insulating substrate 1 has a thickness
It has a diameter of about 0.3 to 1.5 mm and has a plurality of through holes 5 having a diameter of about 0.1 to 1.0 mm from its upper surface to its lower surface.
A part of the wiring conductor 2 is attached to the upper and lower surfaces and the inner wall of each through hole 5, and the upper and lower wiring conductors 2 are electrically connected through the through hole 5.

Such a core 1a is manufactured by heat-curing a sheet obtained by impregnating a glass fabric with an uncured thermosetting resin, and then drilling the sheet from the upper surface to the lower surface. The wiring conductors 2 on the upper and lower surfaces of the core body 1a
Has a thickness of 3 to 50 μm on the entire upper and lower surfaces of the core 1a sheet.
A certain amount of copper foil is attached and the copper foil is etched to form a predetermined pattern after curing. The wiring conductor 2 on the inner wall of the through hole 5 has a thickness of 3 to 50 μm formed by electroless plating and electrolytic plating on the inner wall of the through hole 5 after the through hole 5 is provided in the core body 1a.
It is formed by depositing a copper plating film of about m.

Further, the core 1a is filled with a resin column 6 made of a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin inside the through hole 5. The resin column 6 is for closing the through hole 5 so that the insulating layer 1b can be formed immediately above and immediately below the through hole 5.
It is formed by filling an uncured paste-like thermosetting resin into the through holes 5 by a screen printing method, thermally curing the resin, and polishing the upper and lower surfaces thereof to be substantially flat. Then, the insulating layer 1 is formed on the upper and lower surfaces of the core 1a including the resin columns 6.
b are stacked.

Insulating layer 1b laminated on the upper and lower surfaces of the core 1a
Has a thickness of about 20 to 60 μm, and has a plurality of through holes 7 having a diameter of about 30 to 100 μm from the upper surface to the lower surface of each layer. These insulating layers 1b serve to provide an insulating space for wiring the wiring conductors 2 at high density. Then, by electrically connecting the upper layer wiring conductor 2 and the lower layer wiring conductor 2 through the through holes 7, it is possible to three-dimensionally form high-density wiring. For such an insulating layer 1b, an uncured thermosetting resin film having a thickness of about 20 to 60 μm is adhered to the upper and lower surfaces of the core body 1a, which is heat-cured and the through holes 7 are punched by laser processing. Further, it is formed by successively stacking the next insulating layer 1b thereon in the same manner. In addition, each insulating layer 1b
The wiring conductor 2 deposited on the surface and in the through holes 7 has a known copper plating film having a thickness of about 5 to 50 μm on the surface of each insulating layer 1b and in the through holes 7 each time each insulating layer 1b is formed. It is formed by applying a predetermined pattern by a pattern forming method such as a semi-additive method or a subtractive method.

The wiring conductor 2 formed from the upper surface to the lower surface of the insulating substrate 1 functions as a conductive path for connecting each electrode of the semiconductor element 4 to an external electric circuit board, and is provided on the upper surface of the insulating substrate 1. Part of the portion exposed on the lower surface of the insulating substrate 1 is an electronic component connection pad 2a joined to each electrode of the semiconductor element 4 via a solder bump 8 made of, for example, a lead-tin eutectic alloy. A pin attachment pad 2b for joining the lead pin 3 as an external connection terminal is formed, and the lead pin 3 is erected on the pin attachment pad 2b via a solder 9 such as a lead-tin-antimony alloy.
Such an electronic component connection pad 2a and a pin attachment pad 2b have an outer peripheral portion of a substantially circular pattern connected to the wiring conductor 2 as an outermost layer called a solder resist, as shown in FIG. 15 to 150 depending on insulating layer 1b
If the diameter φ of the electronic component connection pad 2a is approximately 70 by covering with a width of about μm and defining the outer peripheral edge thereof,
Approximately 200 μm, approximately 0.5 for pinned pad 2b
It is formed to be about 2.5 mm. It should be noted that the solder resist 1b as described above is used to solder the electronic component connecting pads 2a or the solder 8 or 9 between the pinning pads 2b.
This effectively prevents an electrical short circuit due to the above, and the bonding strength of the electronic component connection pad 2a and the pin attachment pad 2b to the insulating substrate 1 is high.

Further, the lead pin 3 joined to the pin attachment pad 2b functions as an external connection terminal for connecting the mounted semiconductor element 4 to an external electric circuit.

In this wiring board, the electrodes of the semiconductor element 4 are bonded to the electronic component connection pads 2a through the solder bumps 8 to mount the semiconductor element 4, and the semiconductor element 4 is covered with a lid or a cover (not shown). An electronic device is formed by sealing with potting resin, and the electronic device of the present invention is mounted on the external electric circuit board by connecting the lead pin 3 in the electronic device to the wiring conductor of the external electric circuit board via a socket or solder. The Rukoto.

The lead pin 3 is, for example, 97.57% by weight of copper / 2.3% by weight of iron, as shown in the enlarged cross-sectional view of the main part in FIG.
/ Copper alloy containing 0.1% by weight of zinc / 0.03% by weight of phosphorus, diameter A is about 0.25-0.5 mm and length is 1-3.5 m
The diameter B is 0.45 to 1. at the upper end of the substantially cylindrical shaft portion 3a of about m.
It is formed by forming a substantially disk-shaped large-diameter portion 3b called a nail head having a thickness of 25 mm and a thickness C of about 0.05 to 0.3 mm. Then, 82% by weight of lead is attached to the pad 2b with the large diameter portion 3b.
/ Elastic content containing 10% by weight of tin / 8% by weight of antimony
The lead pins 3 are erected on the pin attachment pads 2b by joining them via solder of 50 GPa or less. As described above, according to the wiring board with a pin and the electronic device using the same of the present invention, since the lead pins 3 are made of a copper alloy, the thermal expansion coefficient of the insulating substrate 1 and the lead pins 3 is 15 ppm.
It becomes close to about / ° C, and it is possible to effectively prevent generation of a large stress due to a difference in thermal expansion coefficient between them. Also, the elastic modulus of the solder 9 is 50 GP.
Since it is a or less and is easily elastically deformed, the lead pin 3
The stress generated between the lead pin 3 and the pin attachment pad 2b due to the external force applied to the solder 9 can be favorably absorbed by the solder 9.

Incidentally, such a lead pin 3 has a shaft portion 3
It is manufactured by preparing a wire made of a copper alloy having a diameter substantially the same as that of a, subjecting the wire to heat treatment, and then crushing one end of the wire by a press to form a large-diameter portion 3b.

Further, the lead pin 3 is attached to the pin pad 2b.
In order to bond to the pin via the solder 9, a predetermined amount of a solder paste for the solder 9 is applied to the pin attachment pad 2b by screen printing using a metal mask, and on the large diameter portion 3b of the lead pin 3 is applied thereon. A method of abutting the end faces against each other, heating them to melt the solder 9 and then cooling to room temperature is adopted.

Further, in the present invention, the lead pin 3
Has an elastic modulus of 90 to 120 GPa and a Vickers hardness of 110 to 160 Hv. And that is important. In this way, the elastic modulus of the lead pin 3 is 90 to 120.
Since it is GPa and the Vickers hardness is 110 to 160 Hv, when the pulling force is applied to the lead pin 3, the stress due to the pulling force is applied to the large diameter portion 3b.
Is appropriately elastically and plastically deformed so that the solder 9
Can be dispersed substantially evenly on the surface and inside, and even if the lead pin 3 is pulled with a force of about 50 N, the solder 9 will not be broken from the surface or inside and the lead pin 3 will be removed. The mounted electronic component 4 can be normally connected to an external electric circuit.

When the elastic modulus of the lead pin 3 is less than 90 GPa or the Vickers hardness is less than 110 Hv, the large diameter portion 3b is largely elastic due to the stress caused by pulling the lead pin 3 when the pulling force is applied to the lead pin 3. Deformation and plastic deformation cause a large stress to act on the solder 9 existing between the top surface of the large-diameter portion 3b and the pinning pad 2b, and even if the lead pin 3 is pulled with a force of, for example, about 30N, The solder 9 easily breaks from the inside of the solder 9 existing between the top surface of the large portion 3b and the pinning pad 2b. On the other hand, when the elastic modulus exceeds 120 GPa or the Vickers hardness exceeds 160 Hv, when the lead pin 3 is pulled vertically or diagonally, the pulling force of the lead pin 3 is largely applied to the outer peripheral portion of the large diameter portion 3b. , The force acts largely on the surface of the solder 9 existing between the side surface of the large diameter portion 3b and the pin attachment pad 2b, and even if the lead pin 3 is pulled by a force of about 30N, the large diameter Part 3b side surface and pin attachment pad 2b
The solder 9 is likely to break from the surface of the solder 9 existing between and. Therefore, the elastic modulus of the lead pin 3 is
Vickers hardness of 110-160H in the range of 90-120GPa
It is specified in the range of v.

The elastic modulus of the lead pin 3 is 90 to 120G.
To set the Pa and Vickers hardness to the range of 110 to 160 Hv, for example, the lead pin 3 has 97.57% by weight of copper / 2.3% by weight of iron.
If it is made of a copper alloy containing 0.1% by weight of zinc / 0.1% by weight of phosphorus / 0.03% by weight of phosphorus, 350
The heat treatment may be performed at a temperature of ~ 450 ° C for about 5 minutes. In this case, if the heat treatment temperature is lower than 350 ° C, it becomes difficult to set the elastic modulus of the lead pin 3 to 120 GPa or less or the Vickers hardness to 160 Hv or less.
It becomes difficult to set 0 GPa or more or the Vickers hardness to 110 Hv or more.

If the ratio B / A of the diameter A of the shaft portion 3a of the lead pin 3 to the diameter B of the large diameter portion 3b is less than 1.8, the lead pin 3 is pulled when the lead pin 3 is pulled vertically or diagonally. A large pulling force is applied to the outer peripheral portion of the large-diameter portion 3b, and as a result, the force is largely concentrated and acts on the surface of the solder 9 existing between the side surface of the large-diameter portion 3b and the pinning pad 2b. Even when the lead pin 3 is pulled with a force of less than 50 N, the solder 9 exists from the surface of the solder 9 existing between the side surface of the large diameter portion 3b and the pin attachment pad 2b.
On the other hand, when B / A exceeds 2.5, when the lead pin 3 is pulled vertically or diagonally, the pulling force of the lead pin 3 is largely applied to the central portion of the large diameter portion 3b, As a result, the force largely acts on the inside of the solder 9 existing between the top surface of the large-diameter portion 3b and the pinning pad 2b via the top surface of the large-diameter portion 3b.
Even if the lead pin 3 is pulled with a force of less than 50 N, there is a risk that the solder 9 will break from the inside of the solder 9 existing between the top surface of the large diameter portion 3b and the pinning pad 2b. Therefore, the ratio B / A between the diameter A of the shaft portion 3a of the lead pin 3 and the diameter B of the large diameter portion 3b is preferably in the range of 1.8 ≦ B / A ≦ 2.5.

If the ratio B / C of the diameter B of the large diameter portion 3b and the thickness C of the large diameter portion 3b is less than 3.4, the force for pulling the lead pin 3 when pulling the lead pin 3 vertically or obliquely. Is largely applied to the outer peripheral portion of the large diameter portion 3b, and as a result, the force is largely concentrated and acts on the surface of the solder 9 existing between the side surface of the large diameter portion 3b and the pinning pad 2b. Even if the lead pin 3 is pulled by the force of the
There is a risk that the solder 9 will break from the surface of the solder 9 existing between the lead pin 3 and the lead pin 3. If B / C exceeds 4.4, the force for pulling the lead pin 3 when pulling the lead pin 3 vertically or diagonally Is largely applied to the central portion of the large-diameter portion 3b, and as a result, the force is large inside the solder 9 existing between the top surface of the large-diameter portion 3b and the pinning pad 2b via the top surface of the large-diameter portion 3b. The large diameter portion 3b acts in a concentrated manner, for example, even when the lead pin 3 is pulled with a force of less than 50N.
There is a risk that the solder 9 will break from the inside of the solder 9 existing between the top surface and the pinning pad 2b. Therefore, the ratio B / C between the diameter B of the large diameter portion 3b and the thickness C of the large diameter portion 3b is preferably in the range of 3.4 ≦ B / C ≦ 4.4. .

Further, the diameter B of the large diameter portion 3b and the distance D from the exposed outer peripheral edge of the pin attachment pad 2b to the large diameter portion 3b.
If the ratio D / B with is less than 0.01, the pin pad 2
Since the joint area between b and the solder 9 becomes small, it becomes difficult to firmly join the pin attachment pad 2b and the solder 9, and when a pulling force is applied to the lead pin 3, this force is generated. The stress that causes pin 2
When the D / B exceeds 0.5, the pin attachment pad 2b is likely to be peeled off from the insulation substrate 1 due to a large effect on the joint between the outer peripheral edge of b and the insulation substrate 1. Since a large amount of solder flows, a large amount of solder 9 is required to form a pool of a suitable size of solder 9 between the large diameter portion 3b and the pin attachment pad 2b. If the lead pin 3 and the pin attachment pad 2b are soldered together, a part of the solder 9 will flow over the large diameter portion 3b to the lower end portion of the lead pin 3, and the lead pin 3 will be connected to the external electrical circuit via a socket or solder. When electrically connecting to the wiring conductor of the substrate, the connection becomes difficult.
Therefore, the diameter B of the large diameter portion 3b and the pin attachment pad 2b
The ratio D / B with the distance D from the outer peripheral edge to the large diameter portion 3b is
The range of 0.01 ≦ D / B ≦ 0.5 is preferable.

Thus, according to the wiring board with a pin and the electronic device using the same of the present invention, even if the lead pin 3 is pulled vertically or diagonally with a force of about 50 N, the lead pin 3 is not removed from the insulating substrate 1. It is possible to provide a wiring board with a pin and an electronic device capable of normally operating the mounted electronic components.

It is needless to say that the present invention is not limited to the above-mentioned example of the embodiment, and various modifications can be made without departing from the scope of the present invention.

[0029]

According to the wiring board with a pin and the electronic device using the same of the present invention, the elastic modulus of the lead pin is 90 to 12;
Since it is 0 GPa and the Vickers hardness is 110 to 160 Hv, when the pulling force is applied to the lead pin, the stress due to the pulling force causes the large-diameter portion to be appropriately elastically and plastically deformed, and It can be dispersed almost uniformly on the surface and inside. As a result, even if the lead pin is pulled with a force of about 50 N, the solder will not be broken from the surface or inside and the lead pin will not be removed, and mounting It is possible to normally connect the electronic components to the external electric circuit.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of an embodiment of a wiring board with pins and an electronic device according to the present invention.

FIG. 2 is an enlarged plan view of an essential part of an example of an embodiment of a wiring board with pins and an electronic device according to the present invention.

FIG. 3 is an enlarged sectional view of an essential part of an example of an embodiment of a wiring board with pins and an electronic device according to the present invention.

[Explanation of symbols]

1 ... Insulating substrate 2 ... Wiring conductor 2b ... Pinning pad 3 ... Lead pin 3a ... Shaft 3b ... Large diameter part 4 ... Semiconductor element as an electronic component 9: Solder

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 23/50 H01L 23/12 P

Claims (2)

[Claims] 1. A pin attachment pad electrically connected to the wiring conductor is provided on a lower surface of an insulating substrate made of an organic material having a wiring conductor, and the pin attachment pad has a substantially cylindrical upper end at an upper end thereof. A wiring board with a pin, wherein a lead pin made of a copper alloy forming a disk-shaped large-diameter portion is erected upright with solder interposed between the large-diameter portion and the pin attachment pad, The elastic modulus of the lead pin is 90 to 12
0 GPa and Vickers hardness of 110-1
A wiring board with a pin, which is 60 Hv. 2. A pin attachment pad electrically connected to the wiring conductor is provided on a lower surface of an insulating substrate made of an organic material having a wiring conductor, and the pin attachment pad has a substantially cylindrical upper end at an upper end thereof. An electronic component is mounted on a wiring board with a pin in which a lead pin formed by providing a disk-shaped large-diameter portion is erected with solder interposed between the large-diameter portion and the pin-attaching pad, and the electronic component is mounted on the wiring board. It is an electronic device which electrically connects an electrode of a component and the wiring conductor, wherein the lead pin has an elastic modulus of 90 to 120 GPa and a Vickers hardness of 110 to 160 Hv. Electronic device to do.