JPH1140940A - Structure and method for soldering ball grid array semiconductor package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the bonding strength of a solder ball, etc., to a pad part, improve the reliability of a bump, improve the yield and reduce the sizes, with respect to a BGA semiconductor package. SOLUTION: On a base material 1a for a BGA semiconductor package or on the surface of a pad part 5 formed on the base material of a printed board as a motherboard, a small recess 6 to which a molten solder ball, etc., can enter is formed by etching with a circuit 4 and the pad part 5. A solder ball 8, etc., is applied and molten on the base material and into the recess 6 to be hardened and bonded. Thus, external output bump 9a to a printed board 10 as a motherboard or a bump to a BGA semiconductor package side is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball grid array (BGA).
) -Type semiconductor package (including micro BGA) and a soldering method.

More specifically, external output bumps (ball grid arrays) in which solder balls or the like (including solder paste, hereinafter the same) are bonded to pad portions (also referred to as lands, hereinafter the same) on a base material of a BGA type semiconductor package, Alternatively, for a bump (ball grid array) in which a solder ball or the like is bonded to a pad portion on a printed circuit board as a motherboard, a soldering structure in a BGA type semiconductor package for the purpose of improving the bonding strength (half-strength). And a soldering method.

[0003]

2. Description of the Related Art Recently, BGA has rapidly spread as one of the techniques for connecting a semiconductor package to a printed circuit board. In this method, a pad portion continuous with a circuit (including a lead pin, the same applies hereinafter) is provided in a grid pattern on an insulating base material, and a solder ball or the like is mounted on the pad portion and an external output bump ( (A ball grid array), and this semiconductor package is connected to another printed circuit board called a motherboard (for example, Jo).
hn H.H. Lau, "Ball Grid Array
Technology "McGraw-Hill, I
nc. Published, 1995, "Nikkei Micro Device"
Magazine, March 1994, P.M. 58-64 etc.).

In the above BGA type semiconductor package,
For example, as shown in FIG. 17, in order to bond a solder ball 8 serving as an external output bump to the pad portion 5, a copper film layer 2 formed on an insulating base material 1a such as a polyimide resin is etched to form a circuit 4 And a pad portion 5 subsequent thereto are formed, a solder resist 7 is applied so that the pad portion 5 is exposed, and a solder ball or the like 8 is applied to the pad portion 5 exposed therefrom.
(Including the application of solder paste, the same applies hereinafter), reflowed and melted, and joined to the pad portion 5 to form the bump 9
a.

[0005]

In a process of mounting an electronic component, when a solder ball or the like is bonded to a pad portion to form a bump, the bonding strength between the pad portion and the solder ball or the like is determined by the semiconductor package. Has a significant effect on the reliability of electrical components using

However, in the conventional BGA type semiconductor package, as shown in FIG. 17 and, for example, as shown in each of the figures of Japanese Patent Application Laid-Open No. HEI 8-111578, the pad portion 5 is formed from the solder resist 7. In the exposed portions, the surface area to which the solder balls 8 and the like 8 are bonded is limited, and the surface of the pad portion 5 is flat (see also, for example, FIGS. 2 and 8 in JP-A-7-313399). ).
Therefore, even when the molten solder ball 8 or the like 8 is bonded to the pad portion 5, the bonding area is small, the solder ball 8 is easily peeled, and the bonding strength is insufficient.

As a result, the bumps of the conventional BGA type semiconductor package cannot be said to have very high reliability of bonding strength with the pad portion, and for example, the yield is low as a semiconductor package used for a vehicle-mounted or portable device. It was bad.
Therefore, if the joining strength is to be increased, it is necessary to increase the size of the pad portion, the solder ball, and the like, which leads to an increase in the size of the device.

This applies not only to external output bumps on a printed circuit board as a motherboard in a BGA type semiconductor package, but also to bumps in a BGA type semiconductor package on a printed circuit board as a motherboard.

In addition, the diameter of a solder ball or the like has recently been set at 0.3 mm.
Although the diameter of the solder ball is 3 to 0.6 mm, since the diameter of the solder ball and the like tends to be further reduced in the future, and the plating of the pad portion tends to be performed by electroless plating, the solder ball and the like are also considered from this surface. The reliability of the bonding strength becomes a problem.

The present invention has been made as a result of a study aimed at solving the above-mentioned problems of the conventional soldering structure and soldering method for a BGA type semiconductor package. That is, an object of the present invention is to increase the bonding strength of a solder ball or the like bonded thereto even if the area of the pad portion is small, to increase the reliability as a bump, to improve the yield, and to improve the BGA type semiconductor package. It is an object of the present invention to provide a soldering structure and a soldering method in a BGA type semiconductor package that can reduce the size of a semiconductor device.

[0011]

[Means for Solving the Problems]

A) The first of the soldering structures in the BGA type semiconductor package according to the present invention is that the solder balls or the like at the time of melting enter the surface of the pad portion 5 formed on the base material 1a for the ball grid array type semiconductor package. A possible small recess 6 is formed, a molten solder ball 8 or the like 8 is inserted into the recess 6 and joined to form an external output bump 9a to a printed board 10 as a motherboard (for example, FIG. 1).

(B) The second aspect of the soldering structure in the BGA type semiconductor package according to the present invention is that a solder ball or the like at the time of melting enters the surface of the pad portion 5 formed on the substrate 1b for a printed circuit board as a motherboard. A possible small recess 6 is formed, and a molten solder ball 8 or the like 8 is also inserted into the recess 6 and joined to form a bump 9b with the ball grid array type semiconductor package side (for example, (See FIG. 2).

(C) The third of the soldering structures in the BGA type semiconductor package according to the present invention is the above (a) or (b).
In the soldering structure described in 1 above, the small recess 6 formed in the pad portion 5 and into which a solder ball or the like at the time of melting can enter.
Is formed at the same depth as the thickness of the copper film layer 2.

(2) Fourth of the soldering structure in the BGA type semiconductor package according to the present invention is the above (a) or (b).
In the soldering structure described in 1 above, the small recess 6 formed in the pad portion 5 and into which a solder ball or the like at the time of melting can enter.
Is formed shallower than the thickness of the copper film layer 2.

E) A first method of soldering a BGA type semiconductor package according to the present invention is a ball grid circuit.
A photosensitive resist film 3 is formed on the surface of the copper film layer 2 formed on the substrate 1a for the array type semiconductor package, and is exposed and developed and then etched to form a circuit 4 and a pad portion 5 and at the same time, the pad portion 5 is formed. After forming a small recess 6 on the surface into which a solder ball 8 at the time of melting can enter, and applying a solder resist 7 on the substrate 1a so that the pad portion 5 is exposed, the solder ball is applied to the pad portion 5. And the like are filled and melted, hardened in a state of entering the recess 6 and joined to the pad portion 5 to form an external output bump 9a on a printed circuit board 10 as a motherboard. is there.

F) A second method of soldering a BGA type semiconductor package according to the present invention is to form a photosensitive resist film 3 on the surface of a copper film layer 2 formed on a substrate 1b for a printed circuit board as a motherboard. The circuit 4 and the pad portion 5 are formed by etching after exposure and development, and at the same time, a small recess 6 is formed on the surface of the pad portion 5 into which a solder ball 8 at the time of melting can enter, so that the pad portion 5 is exposed. After applying the solder resist 7 on the substrate 1b as described above,
The pad portion 5 is filled with a solder ball 8 or the like, melted, hardened while entering the recess 6 and joined to the pad portion 5 to form a bump with the ball grid array type semiconductor package side. 9b.

G) The third method of soldering the BGA type semiconductor package according to the present invention is the above-mentioned e) or f).
In the soldering method described in 1 above, the copper film layer 2 is fully etched to form the circuit 4 and the pad portion 5 and, at the same time, to form a recess 6 having the same depth as the thickness of the copper film layer 2 from the surface of the pad portion 5.
Is formed.

H) The fourth of the soldering methods for the BGA type semiconductor package according to the present invention is the above e) or f).
In the soldering method described in 1 above, the copper film layer 2 is half-etched to form a recess 6 smaller than the thickness of the copper film layer 2 from the surface of the pad portion 5 simultaneously with the formation of the circuit 4 and the pad portion 5. It was made.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is formed on a pad portion of a BGA type semiconductor package. The present invention relates to a case of an external output bump to a printed circuit board as a motherboard, and a case formed on a pad portion of a printed circuit board as a motherboard. This includes the case of the bump with the BGA type semiconductor package side.

The substrates 1a and 1b are made of an insulating resin, preferably made of a polyimide resin. However, the material is not limited to this, and may be made of, for example, a polyester resin. Is also good. Here, the solder ball or the like 8 includes a solder paste in addition to the solder ball, and the filling of the solder ball or the like 8 includes a case where the solder paste is applied and printed.

The copper film layer 2 may be formed by laminating a copper foil on the substrates 1a and 1b or by copper plating. Alternatively, copper plating may be performed after lamination.

In order to form a small recess 6 in the pad portion 5 at the joint surface with the solder ball 8 or the like, a photosensitive resist film (dry film) is formed on the surface of the copper film layer 2 formed on the substrates 1a and 1b. And electrodepositable photosensitive resist) 3 to form
Masking with a mask (not shown) having a pattern for forming circuits (including lead pins), pads and small recesses, etching after exposure and development, and formation at the same time as formation of circuits 4 and pads 5 Good to do.

The shape of the recess 6 has such a depth that the bonding area with the solder ball 8 or the like becomes large, and the solder ball 8 at the time of melting enters the recess 6 and hardly comes out after hardening. It is desirable.

The planar shape of the recess 6 may be a large number of holes (see FIGS. 7 and 10), a lattice (see FIG. 12), or a multi-circle (see FIG. 13). ) Or a spiral shape (not shown). The depth of the recess 6 may be made equal to the thickness of the copper film layer 2 by full etching when the circuit 4 and the pad portion 5 are formed, but the depth of the recess is determined by a mask (dry plate or film) at the time of exposure. If the portion where 6 is formed is made smaller or thinner and etched, half-etching is performed and the copper film layer 2 is partially etched (see FIGS. 14 and 15).

After the above etching, the photosensitive resist film 3
After peeling, the solder resist 7 is applied so that the surface of the pad portion 5 is exposed, and the exposed pad portion 5 is plated. It is desirable to use a liquid resist having photosensitivity for the solder resist 7, but the present invention is not limited to this. In addition, the plating is performed by performing nickel plating as so-called base plating, followed by gold plating, silver, or palladium plating. .

In the above plating method, the pad portion 5 is
(For example, those shown in FIGS. 12 and 13) are electroless-plated, and the pad portions 5 are not divided (for example, those shown in FIGS. 7 and 10 or spirals). Then, electrolytic plating or electroless plating may be used. Even if the recesses 6 have a lattice shape or multiple circles (concentric circles), if the pad portions 5 are partially connected and are not completely divided (for example, see FIG. 16), electrolytic plating may be used.

The soldering structure and the soldering method in the BGA type semiconductor package according to the present invention have the following effects.

A small recess 6 into which the solder ball 8 at the time of melting can enter is formed on the joint surface of the pad portion 5 on the base material 2 with the solder ball 8. Therefore, the pad portion 5
Is smaller than the conventional flat pad portion.
As a result, the bonding area with the molten solder ball 8 or the like is increased, and the solder ball 8 or the like 8 that has entered the recess 6 hardens therein, so that it hardly comes off like an anchor bolt, and it is strongly bonded ( 11 and 15).

Therefore, the bonding strength (soldering strength) of the solder balls 8 and the like is greatly increased as compared with the conventional bonding with a flat pad portion, and the reliability as a semiconductor device using this BGA type semiconductor package is increased. The reliability is improved even when used in, for example, a vehicle-mounted or portable device. In addition, since the bonding strength is high even if the diameter of the pad portion 5 or the solder hole 8 is reduced, the size of the device can be easily reduced.

On the other hand, a small recess 6 of the pad portion 5 is formed by applying a photosensitive resist 3 to the surface of the copper film layer 2 on the base materials 1a and 1b, masking the film, exposing it to light, developing it, and etching it. What is necessary is just to form simultaneously with the formation of the circuit 4 and the pad part 5. Therefore, it is easy to add the steps of the present invention to a series of manufacturing steps and mounting steps of a BGA type semiconductor package, and the present invention can be implemented by partially improving existing equipment.

The recess 6 is formed by etching as described above.
Is formed, the planar shape of the recess 6 can be arbitrarily designed by using a mask at the time of exposure. Depending on whether the etching is half-etching or full-etching, the recess 6
Can be designed arbitrarily, and it is easy to adapt to the use and type of the BGA type semiconductor package, thereby improving the productivity and the yield.

As described above, the increase in the bonding strength of the solder ball or the like 8 is due to the fact that the diameter of the solder ball or the like 8 will become smaller in the future and the electroless plating which tends to weaken the bonding strength with the solder ball or the like will increase. This is a more effective means.

In the figure, reference numeral 11 denotes a concave hole formed in the photosensitive resist film 3, 12 denotes a semiconductor chip, 13 denotes a filling resin, and 14 denotes a through hole.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment is shown in FIGS. 1 and 3 to 15 and shows a case where the present invention is applied to a tape BGA type semiconductor package.

In FIG. 3, reference numeral 1a denotes a substrate having a copper film layer 2 laminated on the surface thereof. Here, a tape-shaped substrate made of a polyimide resin is used as the substrate 1a, and a transfer sprocket is provided on both sides thereof. Holes and positioning holes (both not shown) are formed by punching. The copper film layer 2 may be formed by copper plating.

In FIG. 4, reference numeral 3 designates a photosensitive resist film formed on the surface of the copper film layer 2, in which a liquid photosensitive resist is applied, but a opaque portion remains after the next exposure and development. It may be a mold or a negative mold in which a transparent portion remains. Here, a positive type which is considered to have high accuracy is used.
From above, exposure is performed by masking with a mask (not shown) for forming a small recess 6 on the surface of the pad portion 5 together with the circuit 4 and the pad portion 5.

FIG. 5 shows a state after exposure and development. In this case, the resist film 3 remains on a portion to be a circuit and a portion to be a pad in the copper film layer 2 but becomes a pad. In a portion of the resist film 3, a concave hole 11 forming a small concave portion is formed.
Are formed.

FIG. 6 shows a state after the copper film layer 2 is etched. Only the copper film layer 2 on the portion to be the circuit 4 and the portion to be the pad portion 5 covered with the resist film 3 is left. Portions of the copper film layer have been removed. Further, the copper film layer 2 is also removed in the above-mentioned concave hole 11 in a portion to become the pad portion 5, and a small concave portion 6 is formed. FIG. 7 shows a plan view at that time.

FIG. 8 shows a state after the resist film 3 is peeled off. At the same time when the circuit 4 and the pad portion 5 are formed, a small recess 6 is formed in a part of the pad portion 5. A plurality of small holes are formed as the recesses 6. Further, here, the depth of the recess 6 is set to a depth corresponding to the thickness of the copper film layer 2 by full etching. It is to be noted that the half etching may be performed up to the middle of the thickness of the copper film layer 2, and the shape of the recess 6 is not limited to a small hole as described above.

In FIG. 9, reference numeral 7 denotes a solder resist applied so as to expose the surface of the pad portion 5, and FIG. 10 is a plan view thereof. A liquid resist having photosensitivity was used for the solder resist 7 here. The exposed pad portion 5 is plated with gold after nickel plating as a so-called base plating. However, since the concave portion 6 is not divided by the hole portion, the pad portion 5 is subjected to electrolytic plating. .

When the recess 6 is formed into a lattice or multiple circles and the pad portion 5 is divided into a plurality of portions by full etching, electroless plating may be performed. As described above, if the pad portion 5 is not completely divided by being partially connected even in a lattice shape or a multi-circle shape (see FIG. 16), electrolytic plating may be performed as described above.

FIG. 11 shows a state in which a solder ball 8 or the like 8 is soldered to the pad portion 5. Here, a solder ball or the like 8 is filled after the flux is applied to the pad portion 5 as necessary, and the solder ball 8 is reflowed and melted, and a part of the solder ball 8 enters the small recess 6 of the pad portion 5. In this state, both are cured and the two 5 and 8 are joined to form an external output bump 9a (ball grid array).

FIG. 17 shows a conventional type in which the bonding state is compared with that of the conventional type, and the solder balls 8 and the pad portions 5 are merely planar connections. However, in the case of the present invention, as shown in FIGS. 11 and 15, the solder balls 8 and the like join the surface of the pad portion 5 and also enter the small recesses 6 and join, so that the joining area increases. It can be seen that it has become difficult to come off because of the anchor bolt shape.

Next, the embodiment shown in FIG.
The present invention relates to a bump on a printed circuit board side as a mother board on which a BGA type semiconductor package is mounted, not a bump on an A type semiconductor package.

Here, a photosensitive resist film is formed on the surface of the copper film layer 2 formed on the substrate 1b for a printed circuit board as a motherboard in the same manner as described above, and is exposed and developed, and then etched to form a circuit 4. Simultaneously with the formation of the pad portion 5, a small recess 6 into which a solder ball or the like at the time of melting can enter is formed on the surface of the pad portion 5. The resist film here was used by pressing a dry film (dry film-shaped photosensitive resist).

After applying a solder resist 7 on the substrate 1b so that the pad portions 5 are exposed, silver plating is performed by electroless plating on nickel plating as a base on the exposed pad portions 5 and thereafter, The pad portion 5 was filled with a solder ball 8 or the like, and was reflowed and melted. As a result, the solder balls 8 and the like 8 enter the recess 6, and are cured and joined to the pad portion 5.

As a result, bumps 9b for connecting to the BGA type semiconductor package side are formed.
In this case, similarly to the case of the above-described embodiment, the solder balls 8 and the like 8
Are bonded to the surface of the pad portion 5 and each of the small recesses 6
It also penetrates into the inside and joins, and the joining area increases, and it is difficult to be detached in the form of an anchor bolt.

Also in this embodiment, the copper film layer 2 is fully etched to form a recess 6 having the same depth as the thickness of the copper film layer 2 in the pad portion 5 simultaneously with the formation of the circuit 4 and the pad portion 5. It may be formed, or the concave portion 6 shallower than the thickness of the copper film layer 2 may be formed by half-etching the copper film layer 2.

In any of the above embodiments, the solder balls 8
As described above, the filling may be performed by applying and printing a solder paste.

[0050]

As is clear from the above, the BG according to the present invention is
According to the soldering structure and the soldering method in the A-type semiconductor package, the bonding strength (soldering strength) when bonding the solder ball or the like to the pad portion can be increased, and the reliability of the bonding of the bump can be improved. It is possible to improve the yield and improve the reliability of the BGA type semiconductor package for use in, for example, a vehicle-mounted device or a portable device, and reduce the size of the device.

That is, in the pad portion of the conventional BGA type semiconductor package, the surface area of the pad portion to which the solder ball or the like is bonded is limited, and the surface is flat, so that the solder ball bonded to the pad portion is used. And the like, the bonding strength was not sufficient, and there was a problem in the reliability as a bump. Further, in order to increase the bonding strength, the pad portion and the solder ball become large, which has contributed to the increase in the size of the device.

On the other hand, in the present invention, by forming a small recess on the surface of the pad portion into which a solder ball or the like at the time of melting can enter as described above, the pad portion and the molten solder ball or the like are formed. The bonding area between them can be increased, and the melted solder ball bites into the recess and hardens, so that it hardly comes off like an anchor bolt, and a strongly bonded bump can be formed.

As a result, the bonding strength can be greatly increased as compared with the conventional bonding with a flat pad, and the reliability as a bump in a BGA type semiconductor package can be improved. The joint strength can be maintained even if the size is reduced, which is useful for miniaturization of equipment.

The small recess on the surface of the pad portion is formed by applying a photosensitive resist on the surface of the copper film layer, exposing and developing, and then etching. Therefore, since the circuit and the pad portion can be formed at the same time as the formation, the process of the present invention can be easily added to a series of manufacturing and mounting processes of the BGA type semiconductor package.

Further, the planar shape of the recess can be arbitrarily designed by the masking pattern at the time of exposure, and the depth of the recess can be arbitrarily designed by performing half etching or full etching. . Therefore, the recess can be formed in accordance with the use and the type of the BGA type semiconductor package. From this point, the yield and the productivity of the BGA type semiconductor package can be improved.

Further, it is conceivable that the diameter of the solder ball or the like will be further reduced in the future, and the case of electroless plating will increase, so that the above-mentioned increase in the bonding strength of the solder ball or the like becomes more effective. .

[Brief description of the drawings]

FIG. 1 is an enlarged vertical sectional side view showing an embodiment of a soldering structure in a BGA type semiconductor package according to the present invention.

FIG. 2 is an enlarged vertical sectional side view showing another embodiment of the soldering structure in the BGA type semiconductor package according to the present invention.

FIG. 3 is an enlarged vertical sectional side view showing a state where a copper film layer is formed on a base material during the manufacturing process of the embodiment shown in FIG. 1;

FIG. 4 is an enlarged vertical sectional side view showing a state where a photosensitive resist film is formed on a copper film layer in a manufacturing process of the embodiment shown in FIG. 1;

FIG. 5 is an enlarged vertical sectional side view of a state after exposure and development in the manufacturing process of the embodiment shown in FIG. 1;

FIG. 6 is an enlarged vertical sectional side view showing a state after full etching in a manufacturing process of the embodiment shown in FIG. 1;

FIG. 7 is a plan view of what is shown in FIG.

FIG. 8 is an enlarged vertical sectional side view showing a state after a resist film is peeled off in a manufacturing process of the embodiment shown in FIG. 1;

FIG. 9 is an enlarged vertical sectional side view showing a state after a solder resist is applied in a manufacturing process of the embodiment shown in FIG. 1;

FIG. 10 is a plan view of what is shown in FIG. 9;

FIG. 11 is an enlarged vertical sectional side view showing a state where solder balls and the like are joined in the manufacturing process of the embodiment shown in FIG. 1;

FIG. 12 is an enlarged plan view of a pad portion when the recesses are formed in a lattice shape.

FIG. 13 is an enlarged plan view of a pad portion when a concave portion is formed in a multiple circular shape.

FIG. 14 is an enlarged vertical sectional side view showing a case where a recess is formed shallowly by half etching.

FIG. 15 is an enlarged vertical sectional side view showing a state where solder balls and the like are joined to the one shown in FIG. 14;

FIG. 16 is an enlarged plan view of an example in which a pad portion is formed so as not to be divided even if a concave portion has a lattice shape.

FIG. 17 is an enlarged vertical sectional side view showing a conventional example in a state where solder balls and the like are joined to a pad portion.

[Explanation of symbols]

1a-substrate 6-recess 1
1-Concave hole 1b-Base material 7-Solder resist 1
2-semiconductor chip 2-copper film layer 8-solder ball etc. 1
3-filled resin 3-photosensitive resist film 9a-bump 1
4-through hole 4-circuit 9b-bump 5-pad portion 10-printed circuit board

Claims (8)

[Claims] 1. A small recess 6 in which a solder ball or the like at the time of melting can be formed on a surface of a pad portion 5 formed on a base material 1a for a ball grid array type semiconductor package. A soldering structure in a ball grid array type semiconductor package, wherein a ball or the like 8 is inserted into the recess 6 and joined to form an external output bump 9a to a printed circuit board 10 as a motherboard. 2. A small recess 6 into which a solder ball or the like at the time of melting can enter is formed on the surface of a pad portion 5 formed on a substrate 1b for a printed circuit board as a motherboard. A soldering structure in a ball grid array type semiconductor package, wherein the soldering structure is inserted into the recess 6 and joined to form a bump 9b with the ball grid array type semiconductor package side. 3. The ball according to claim 1, wherein the small recess formed in the pad portion and into which a solder ball or the like at the time of melting can enter is formed at the same depth as the thickness of the foil foil layer.・ Soldering structure in grid array type semiconductor package. 4. The ball grid grid according to claim 1, wherein the small recess formed in the pad portion and into which a solder ball or the like at the time of melting can enter is formed shallower than the thickness of the copper film layer. Soldering structure in array type semiconductor package. 5. A circuit 4 and a pad portion 5 are formed by forming a photosensitive resist film 3 on the surface of a copper film layer 2 formed on a substrate 1a for a ball grid array type semiconductor package, exposing and developing, and then etching. At the same time as forming a small recess 6 on the surface of the pad portion 5 into which a solder ball 8 at the time of melting can enter, and applying a solder resist 7 on the base material 1a so that the pad portion 5 is exposed. The pad portion 5 is filled with a solder ball 8 or the like, melted, hardened in a state where the pad portion 5 also enters the recess 6, and bonded to the pad portion 5, and an external output bump to a printed board 10 as a motherboard is formed. 9a. A soldering method for a ball grid array type semiconductor package, wherein the soldering method is formed in 9a. 6. A photosensitive resist film 3 is formed on a surface of a copper film layer 2 formed on a substrate 1b for a printed circuit board as a motherboard.
Then, after exposure and development, etching is performed to form the circuit 4 and the pad portion 5, and at the same time, a small recess 6 into which a solder ball 8 at the time of melting can enter is formed on the surface of the pad portion 5. After the solder resist 7 is applied on the substrate 1b so that the solder paste 5 is exposed, the pad portion 5 is filled with a solder ball 8 or the like, melted, and cured while entering the recess 6 so that the pad portion 5 is hardened. 5. A soldering method for a ball grid array type semiconductor package, wherein the bumps 9b are formed so as to form bumps 9b with the ball grid array type semiconductor package side. 7. The circuit 4.
7. The ball grid array type semiconductor according to claim 5, wherein a recess 6 having a depth equal to the thickness of the copper film layer 2 is formed from the surface of the pad portion 5 simultaneously with the formation of the pad portion 5. Soldering method for package. 8. The circuit 4 is formed by half-etching the copper film layer 2.
7. The ball grid array type semiconductor package according to claim 5, wherein a concave portion 6 shallower than the thickness of the copper film layer 2 is formed from the surface of the pad portion 5 simultaneously with the formation of the pad portion 5. Soldering method.