JP2000357758A - Semiconductor package and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor package which can suppress generation of defects when they are mounted on a printed board, etc., and which can be easily checked for defects, if any, and also provide a method for manufacturing it. SOLUTION: On the mounting face of a main body 1 of a BGA package, inverted cone-shaped solder electrodes 2 are disposed. The diameter of each solder electrode 2 becomes narrower as it goes away from the main body 1 of a BGA package. The solder electrodes 2 are connected to prescribed electrodes formed on a semiconductor chip. The maximum diameter of the solder electrodes 2 is larger than their heights. A printed board 4 is formed with mounting pads 3, which are soldered with the solder electrodes 2. The main body 1 of a BGA package is provided with a substrate mounted with the semiconductor chip. The substrate is formed with through-holes, which are filled with a conductor layer. The solder electrodes 2 are connected to the conductor layer on the mounting face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor package mounted on a printed circuit board or the like and used, and more particularly to a semiconductor package with improved reliability and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a ball grid array (BGA) package among semiconductor packages, electrodes are arranged in a grid pattern. As a result, the number of electrodes can be significantly increased as compared with the conventional semiconductor package.

FIG. 5 is a schematic view showing a conventional BGA package. On a mounting surface (lower surface) of the BGA package body 51 in which the semiconductor chip is built, an electrode 52 made of a spherical solder ball is arranged. The electrode 52 is connected to a predetermined electrode provided on the semiconductor chip. Also,
A mounting pad 53 is formed on the printed board 54, and the electrode 52 and the mounting pad 53 are soldered.

[0004] Soldering is performed as follows. Paste solder is printed on the mounting pad 53 in advance. Then, the BGA package body 51 is mounted on the printed circuit board 54 so that the position of the electrode 52 is aligned with the mounting pad 53.
Mount on top. Next, the electrode 52 and the printed solder are once melted by heating from the surroundings, and then solidified by cooling. Thus, soldering is performed. Such a soldering method is called a reflow soldering method.

[0005]

However, in the above-described conventional semiconductor package, since the surface area per volume of the electrode 52 is large, heat is easily absorbed, and defects such as unmelting of the solder are likely to occur. . Even if such a defect occurs, the electrode 52 disposed in the center of the BGA package body 51 is hidden, and it is extremely difficult to visually check the soldering quality from outside. There is a problem that there is. Further, there is another problem that it is difficult to remove when repair or the like becomes necessary after soldering.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and can suppress the occurrence of a defect at the time of mounting on a printed circuit board or the like. And a method for manufacturing the same.

[0007]

A semiconductor package according to the present invention comprises a semiconductor chip, a substrate on which the semiconductor chip is mounted, a through hole formed in the substrate, and a conductor buried in the through hole. In a semiconductor package having a layer and an electrode connected to the semiconductor chip via the conductor layer, a height of the electrode from the substrate is larger than a maximum diameter thereof.

In the present invention, since the height of the electrode from the substrate is larger than its maximum diameter, the gap between the electrodes is widened. For this reason, at the time of reflow soldering performed at the time of mounting on a printed circuit board or the like, warm air is blown to the respective electrodes almost uniformly. Further, since the surface area per volume of the electrode is smaller than that of the conventional electrode, heat is hardly absorbed. As a result, the occurrence of defects is reduced. Furthermore, if any failure occurs during mounting on a printed board or the like, the board or the like is in an inclined state, so that it is easy to visually check the quality of soldering.

The electrode is desirably a solder electrode, and the shape may be a spindle shape.

[0010] A method of manufacturing a semiconductor package according to the present invention comprises the steps of: moving at least one of the plates in one direction while holding the solder ball between the two plates to make the shape of the solder ball a spindle shape; Thermocompression bonding the solder ball to a conductor layer provided on a substrate on which a semiconductor chip is mounted such that the longitudinal direction of the solder ball is perpendicular to the mounting surface.

Another method of manufacturing a semiconductor package according to the present invention includes a step of forming a rod-shaped solder material into a spindle shape by using a mold, and a step of forming the solder ball so that a longitudinal direction of the solder ball is perpendicular to a mounting surface. Thermocompression bonding the ball to a conductor layer provided on a substrate on which a semiconductor chip is mounted.

The step of thermocompression bonding the solder ball to the conductor layer includes a step of vertically inserting the solder ball into a hole provided in the case such that one end of the solder ball protrudes from the surface of the case. be able to.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor package according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a configuration of a semiconductor package according to an embodiment of the present invention.

In this embodiment, an inverted conical solder electrode 2 is arranged on a mounting surface (lower surface) of a BGA package body 1 in which a semiconductor chip is built. That is, the diameter of the solder electrode 2 becomes smaller as the distance from the BGA package body 1 increases. The solder electrode 2 is connected to a predetermined electrode provided on the semiconductor chip. The maximum diameter of the solder electrode 2 is larger than its height. Furthermore,
The mounting pads 3 are formed on the printed circuit board 4, and the solder electrodes 2 and the mounting pads 3 are soldered.

Although not shown, the BGA package body is provided with a substrate on which the semiconductor chip is mounted. The substrate is, for example, an epoxy substrate. A through hole is formed in the substrate, and a conductor layer is buried in the through hole. The solder electrode 2 is connected to the conductor layer on the mounting surface.

The soldering is performed as follows. Paste solder is printed on the mounting pad 3 in advance.
Then, the BGA package body 1 is mounted on the printed circuit board 4 so that the position of the solder electrode 2 matches the mounting pad 3. Then, a hot air is blown from below to the solder electrode 2 and the printed solder from below, and the solder electrode 2 and the mounting pad 3 are mechanically melted by heating them, and then cooled and solidified to form a mechanical connection. And electrically connected. In this way, reflow soldering is performed.

In this embodiment, as described above, since the height of the solder electrode 2 is larger than its diameter, when the BGA package body 1 is mounted on the printed board 4,
The gap created between them becomes wider. Therefore, at the time of reflow soldering, since warm air is blown to the respective solder electrodes 2 almost uniformly, the occurrence of defects such as unmelting of the solder is reduced.

Further, since the surface area per volume of the solder electrode 2 is smaller than that of the conventional electrode, excessive heat absorption is improved, and defects such as unmelted solder are reduced.

Furthermore, since the solder electrodes 2 are melted during reflow soldering, the distance between the BGA package body 1 and the printed circuit board 4 is short, and the BGA package body 1 is in a sunk state. When the solder electrode 2 does not melt, only that portion is in a state where it does not sink. As a result, the BGA package body 1
However, the soldering is completed in an inclined state.
Therefore, the occurrence of defects such as unmelted solder can be easily found visually. That is, it is easy to visually confirm the quality of soldering.

Further, before the BGA package body 1 is mounted on the printed circuit board 3 and the soldering is heated, the contact surface between the solder electrode 2 and the mounting pad 3 is small.
Therefore, when the solder is melted by heating,
The occurrence of a soldering failure, in which the solder flows out to the adjacent mounting pad 3 to cause a short circuit, is also suppressed.

The shape of the electrodes provided on the lower surface of the package body is not limited to the inverted conical shape.
Any shape having a height larger than the maximum diameter, such as a pyramid, a cylinder, a prism, and a spindle, can be used.

Next, a method for producing a spindle-shaped solder electrode will be described. FIG. 2 is a schematic diagram showing a first method for producing a spindle-shaped solder electrode, and FIG. 3 is a schematic diagram showing a second method for producing a spindle-shaped solder electrode.

In a first method of manufacturing a spindle-shaped solder electrode, as shown in FIG. 2, a plurality of solder balls 11 are sandwiched between two plates 12 and 13. Then, the upper plate 12 is reciprocated in one direction parallel to its surface. Since the solder ball 11 is made of a relatively soft metal, the solder ball 11 is gradually deformed by the reciprocation of the plate 12 to have a spindle shape.

In the second manufacturing method, as shown in FIG. 3, a pair of molds 22 whose opposite end faces are processed into concave surfaces are used. Then, the bar-shaped solder 21 is arranged between the concave surfaces of the mold 22 and cut by the mold 22, whereby a spindle-shaped solder electrode can be manufactured.

The spindle-shaped solder electrode thus manufactured is a BGA having a built-in semiconductor chip as follows.
Joined to the package body. FIG. 4 is a schematic view showing an example of a method of joining a spindle-shaped solder electrode to a BGA package body.

When joining the spindle-shaped solder electrode 31 to the BGA package body 32, for example, a hole 33 having a diameter substantially equal to the diameter of the solder electrode 31 and a depth slightly smaller than the length of the solder electrode 31 is formed. Case 34 is used. The hole 33 is formed at a position matching the land 35 provided on the BGA package body 32 and connected to the electrode of the semiconductor chip. Then, the spindle-shaped solder electrode 31 is set up in the hole 33 and loosely inserted, thereby performing positioning. After that, the land 35 is brought into contact with the solder electrode 31, a pressure is further applied, and the solder is heated to a temperature slightly lower than a temperature at which the solder melts, thereby performing thermocompression bonding. For example, the solder electrode 31 can be joined to the BGA package body 32 by such a method.

The method of manufacturing the spindle-shaped solder electrode is not limited to the above two examples.

[0028]

As described in detail above, according to the present invention,
Since the height of the electrode from the substrate is larger than its maximum diameter, the gap between the electrodes widens, and hot air is applied to each electrode during reflow soldering performed when mounting on a printed circuit board etc. Can be sprayed almost evenly. Further, since the surface area per volume of the electrode is smaller than that of the conventional electrode, heat is hardly absorbed. As a result, the occurrence of defects can be suppressed. Furthermore, even if any defect occurs during mounting on a printed board or the like, the board or the like is in an inclined state, so that the quality of soldering can be easily visually checked. As a result, high reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a semiconductor package according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a first method for producing a spindle-shaped solder electrode.

FIG. 3 is a schematic view showing a second method for producing a spindle-shaped solder electrode.

FIG. 4 is a schematic view showing an example of a method of joining a spindle-shaped solder electrode to a BGA package body.

FIG. 5 is a schematic view showing a conventional BGA package.

[Explanation of symbols]

 1, 51; BGA package body 2, 52; solder electrodes 3, 53; mounting pads 4, 54; printed circuit board 11, solder balls 12, 13; plate 21, rod-shaped solder 22, metal mold 31, solder electrode 32, BGA package Body 33; Hole 34; Case 35; Land

Claims (6)

[Claims] 1. A semiconductor chip, a substrate on which the semiconductor chip is mounted, a through hole formed in the substrate, a conductor layer buried in the through hole, and the semiconductor chip via the conductor layer. A height of the electrode from the substrate is larger than a maximum diameter of the electrode. 2. The semiconductor package according to claim 1, wherein said electrodes are solder electrodes. 3. The semiconductor package according to claim 1, wherein the shape of the electrode is a spindle shape. 4. A process in which at least one of the plates is moved in one direction while holding the solder ball between two plates to make the shape of the solder ball a spindle shape, and the longitudinal direction of the solder ball is mounted. A method of thermocompression bonding the solder balls to a conductor layer provided on a substrate on which a semiconductor chip is mounted so as to be perpendicular to a surface. 5. A step of forming a rod-shaped solder material into a spindle shape by using a mold, and providing the solder ball on a substrate on which a semiconductor chip is mounted so that a longitudinal direction of the solder ball is perpendicular to a mounting surface. And a step of thermocompression bonding to the provided conductor layer. 6. The step of thermocompression bonding the solder ball to the conductor layer includes the step of inserting the solder ball upright into a hole provided in the case such that one end of the solder ball protrudes from the surface of the case. 6. The method of manufacturing a semiconductor package according to claim 4, wherein