JP2501177B2 - Mounting method of surface mount type semiconductor package - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting a surface-mounting type semiconductor package on a mounting board such as a printed circuit board, which prevents peeling and cracking at the package interface.

[0002]

2. Description of the Related Art In a surface mount type semiconductor package such as a small outline package (SOP), a quad flat package (QFP) or a plastic read chip carrier (PLCC), the size of the semiconductor chip accommodated in the package is large. Along with this, the package strength tends to be smaller and thinner, and the package strength tends to decrease.

When the package is mounted on a mounting substrate such as a printed circuit board, when heat is applied to the package during, for example, solder reflow, moisture entering the package undergoes rapid volume expansion, resulting in peeling of the package interface. It also causes cracks. Conventionally, as one of the countermeasures, before solder reflow, for example, baking is performed at 125 ° C. for a long time, generally for 16 to 24 hours.

An example of a document describing the surface mount type package is "IC mounting technology" P135-156 issued by the Industrial Research Group of January 15, 1980.

[0005]

In the conventional method as described above, a baking oven must be prepared,
Above all, the work efficiency was poor because a long baking time was required.

An object of the present invention is to provide a mounting method for a surface-mounting type semiconductor package which prevents cracking at the interface of the package of the surface-mounting type semiconductor package and has good working efficiency.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0008]

The outline of the representative ones of the inventions disclosed in the present application will be briefly described as follows.

That is, in the method of mounting a surface-mounting type semiconductor package, a step of preparing a surface-mounting type semiconductor package and a package in which a moisture absorbent is sealed in a moisture-proof laminated bag, Consisting of a step of taking out from the laminate bag for mounting, and a step of surface-mounting the surface-mounted semiconductor package taken out of the bag to a mounting board by a solder reflow method,
A method for mounting a surface-mounting type semiconductor package is characterized in that after the package is taken out of the bag, it is quickly surface-mounted on a mounting board.

[0010]

According to the above means, the surface-mounting type semiconductor package and the moisture absorbent are sealed in the moisture-proof laminate bag, and the surface-mounting type semiconductor package is taken out from the laminate bag and quickly surface-mounted by the solder reflow method. Therefore, a troublesome baking work is not required, and the package interface peeling and cracking do not occur even if the solder reflow is performed.
Particularly, in the present invention, the water vapor permeability is 2.0 g / m ² · 24 hrs.
Since the following resin-based bag is made of polyester as a base, it has excellent moisture resistance, heat sealing is possible, and the effect of preventing invasion of outside air is high. The surface resistivity of the bag is 10 ¹¹ Ω or less on the inner surface and 1 on the outer surface in consideration of antistatic.
0 ohm ⁶ Ω or less. Furthermore, in the present invention, since silica gel is placed between the magazine and the wall surface of the interior box, the silica gel absorbs moisture,
Surface mount packages are much less susceptible to external moisture.

[0011]

Next, the present invention will be described based on the embodiments shown in the drawings.

A magazine 2 is housed in an inner box 1 made of paper as shown in FIG. An example of the magazine 2 is shown in FIG. As shown in FIG. 4, the surface mount semiconductor package 3 is packed in the magazine 2, and a stopper 4 is attached to an end of the magazine 2 in order to prevent the package 3 from protruding outside the magazine.

A plurality of the packages 3 are packed in the magazine 2.

As shown in FIG. 2, silica gel 5 is put between the wall surface of the inner box 1 and the side surface of the magazine 2. When the silica gel 5 is inserted into the end portion of the magazine 2, it is good for absorbing moisture, and the flange portion 7 of the lid 6 is connected to the interior box 1.
When the lid 6 is folded inside and the lid 6 is lifted and the package 3 is taken out, the end opening side of the lid 6 is first affected by moisture in the outside air. It is good to provide. The inner box 1 is put in a bag body 8 as shown in FIG. 5, and after deaeration, the opening 9 of the bag body 8 is heat-sealed.

The bag 8 has a moisture permeability of 2.0 g / m ² for example.
-It is composed of a transparent conductive bag based on polyester of 24 hours or less.

The bag 8 is made transparent because it is advantageous in management when the type, quantity, manufacturing lot number, etc. are written on the surface of the inner box 1.

As an example of the resin film forming the conductive bag 8, an antistatic agent-blended polyethylene, a polyester film, a carbon conductive layer, and an acrylic resin protective layer are laminated from the inside, and chloride is further formed on the film. An example is a coating of vinylidene film. The conductive bag 8 has a surface resistivity of 10 ⁶ Ω or less on the outer surface and 10 ¹¹ Ω or less on the inner surface in order to prevent the IC in the package 3 from being charged.

As shown in FIG. 1, a print or label 10 is attached to the surface of the conductive bag 8 with notes such as that it should be used immediately after opening and put again in a low humidity environment. It

According to the present invention, the surface-mounting type semiconductor package 3 is housed in the moisture-proof bag body 8 and further completely sealed by degassing and heat sealing 9, and by the silica gel 5 on the opening side. Since the amount is absorbed and is not affected by external moisture, it is possible to prevent the peeling and cracking of the package interface even if the solder reflow is performed without a troublesome baking work.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, a hygroscopic agent other than silica gel may be used.

[0022]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

According to the present invention, since it is not affected by external moisture, problems such as package interface peeling cracks do not occur even if solder reflow is performed without baking.

Further, since the troublesome baking work is not required, it is possible to mount the surface mounting type semiconductor package with good working efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view of a package showing an embodiment of the present invention,

FIG. 2 is a perspective view of an inner box showing an embodiment of the present invention,

FIG. 3 is a perspective view of an example of a magazine,

FIG. 4 is an explanatory cross-sectional view of a magazine end portion,

FIG. 5 is an explanatory diagram of an example of a bag body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Interior box 2 ... Magazine 3 ... Surface mount type semiconductor package 4 ... Stopper 5 ... Silica gel (hygroscopic agent) 6 ... Lid 7 ... Flange 8 ... Bag 9 ... Bag opening (heat seal) 10 ... Printing or label

Claims (1)

(57) [Claims] 1. A method of mounting a surface-mounted semiconductor package, the method comprising: preparing a package in which a surface-mounted semiconductor package and a moisture absorbent are sealed in a moisture-proof laminated bag;
The surface mounting type semiconductor package is taken out of the laminated bag for surface mounting, and the surface mounting type semiconductor package taken out of the bag is surface mounted on a mounting board by a solder reflow method. A method for mounting a surface-mount type semiconductor package, which comprises quickly mounting the surface on a mounting board after taking it out from a bag.