JPH04314360A - Method for preventing solder bridge between terminals - Google Patents

Abstract

PURPOSE:To provide an extremely simple method for preventing a solder bridge between terminals which is generated between terminals when the terminal of an electronic part is immersed and pulled up in and from molten solder. CONSTITUTION:A method for preventing a solder bridge between terminals is constituted so that a bridge preventing plate 12 which is formed by providing an opening 12b whose size is approximately the same as a terminal 11c to a sheet 12a which is resistant to a temperature of molten solder 13 and does not allow the molten solder to attach thereto corresponding to arrangement of the terminal 11c is adhered to a rear of a package 11a with the terminal 11c through the opening 12b before the terminal 11c is immersed in the molten solder 13, and the terminal 11c is immersed in the molten solder 13.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides a solder bridge between terminals that prevents solder bridges from occurring between adjacent terminals when terminals hanging vertically on an electronic component package are dipped in molten solder and pulled up. The present invention relates to a method for preventing solder bridging between terminals, and particularly to a method for preventing solder bridging between terminals, which can prevent solder bridging between terminals using an extremely simple method.

0002

[Prior Art] Electronic components in which terminals are soldered to wiring patterns on printed circuit boards, such as PGA (PGA), which has a plurality of rod-shaped terminals hanging from the back of a ceramic package.
In a pin grid array type semiconductor device (hereinafter referred to as a semiconductor device), the bondability of solder to the surface of a terminal, that is, the solder wettability of the terminal is usually specified.

[0003] The solder wettability of this terminal is measured by dipping the terminal in so-called molten solder, which is melted within a certain temperature range, for a predetermined period of time, then pulling it out, and then determining how much of the surface of the terminal is covered with new solder. This is to check whether there are any.

By the way, in order to check the solder wettability of terminals of electronic components, such as semiconductor devices, the method shown in FIG.
As shown in , the semiconductor device 11 is placed in a state where the axis is vertical.
25. The terminal 11c of
After immersing the terminal 11c in molten solder 13 held at about 0 degrees for several seconds, the terminal 11c was pulled up vertically to coat the surface of the terminal 11c with solder.

[0005]

By the way, as shown in FIGS. 2(b) and 2(c), the terminals 11c hanging from the back surface of the ceramic package 11a of the semiconductor device 11 are connected to the back surface of the package 11a as shown in FIGS. The soldering pattern 11b is soldered to the soldering pattern 11b, which is conductive and has good solder wettability (good solder adhesion), and its tip is in contact with the center of the soldering pattern 11b.

However, in a semiconductor device having many terminals, the distance between the brazing patterns 11b is 1 m.
There are many that are composed of less than m. For this reason,
When the terminal 11c of such a semiconductor device 11 is immersed up to its base in the molten solder 13 as described above, a solder bridge 14 is formed between the adjacent brazing patterns 11b as shown in FIG. 2(c). From time to time, solder bridges 14 also occur between the terminals 11c that are brazed to these brazing patterns 11b in such a way that they adhere to the solder bridges 14 between the brazing patterns 11b. Note that the solder bridge generated between the brazing pattern 11b causes the terminal 11c to
It goes without saying that the solder bridges incidentally occurring between the two occur simultaneously.

When the solder bridge 14 occurs between the terminals 11c in this way, there is a problem that it becomes impossible to check the solder wettability of the entire surface of the terminals 11c. The present invention has been made to solve these problems, and its purpose is to provide a method for preventing solder bridges between terminals that can prevent solder bridges between terminals in an extremely simple manner. be.

[0008]

[Means for Solving the Problem] As shown in Fig. 1, the above object is to provide a method in which, when a plurality of rod-shaped terminals hanging vertically on the back surface of an electronic component package are simultaneously dipped into molten solder and pulled up, they are adjacent to each other. In the solder bridge prevention method for preventing solder bridges occurring between terminals 11c
Before immersing the terminals 11c in the molten solder 13, openings 12b having approximately the same size as the thickness of the terminals 11c are formed in a sheet 12a that can withstand the temperature of the molten solder 13 and does not allow the molten solder 13 to adhere to the sheet 12a, corresponding to the arrangement of the terminals 11c. The bridge prevention plate 12 provided is connected to the terminal 1 in this opening 12b.
This is achieved by a method for preventing solder bridges between terminals, which is characterized in that the terminals 11c are inserted through the terminals 1c and brought into close contact with the back surface of the package 11a, and the terminals 11c are immersed in the molten solder 13.

[0009]

[Operation] As shown in FIG. 1, in the method for preventing solder bridges between terminals of the present invention, before immersing the terminals 11c in the molten solder 13, a thin sheet 12a is arranged to correspond to the arrangement of the terminals 11c and the thickness of the terminals 11c is The bridging prevention plate 12 is provided with openings 12b of approximately the same size, and the terminals 11c are inserted into and removed from the openings 12b and are attached in close contact with the back surface of the package 11a.

In such a state, the brazing pattern 11b provided on the back surface of the package 11a of the electronic component 11 explained with reference to FIG. 2 and the terminal 11c are separated by the bridge prevention plate 12.

Therefore, the terminal 11c of the electronic component 11
Even if the brazing pattern 11b is immersed in the molten solder 13 up to its base, the solder bridge 14 will not be generated between the terminals 11c because the brazing pattern 11b does not come into contact with the molten solder 13.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for preventing solder bridges between terminals according to an embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a diagram for explaining a method for preventing solder bridges between terminals according to an embodiment of the present invention, and FIG. FIG. 2B is a plan view of the bridge prevention plate, and FIG. 2C is a sectional side view of the main part of a semiconductor device in which the bridge prevention plate is attached to the back surface of the package.

In this specification, the same parts, the same materials, etc. are given the same reference numerals throughout all the drawings. A method for preventing solder bridges between terminals according to an embodiment of the present invention is as shown in FIGS. 11b and terminal 11c
The terminal 11c is immersed in the molten solder 13 after the bridging prevention plate 12 shown in FIG.

This bridging prevention plate 12 is made of molten solder 1.
3, for example, a thin sheet that can withstand the temperature of around 250 degrees Celsius and does not allow this molten solder 13 to adhere, for example, polytetrafluoroethylene (with a thickness of about several tens of micrometers).
The terminals 11c are arranged on a sheet 12a made of Teflon (commonly known as Teflon) in accordance with the arrangement of the terminals 11c of the semiconductor device 11.
The opening 12b is approximately the same size as the thickness of the opening 12b.

[0015] Therefore, this bridging prevention plate 12 is
When the terminal 11c of the semiconductor device 11 is removably inserted into the opening 12b provided in the sheet 12a and brought into close contact with the back surface of the package 11a, the semiconductor device 1
Brazing pattern 11 on the back side of package 11a of No. 1
b and the terminal 11c are separated by this bridge prevention plate 12.

The terminal 11c of the semiconductor device 11 in such a state
Even if the brazing pattern 11b is immersed in the molten solder 13 up to its base, the solder bridge 14 will not be generated between the terminals 11c because the brazing pattern 11b does not come into contact with the molten solder 13.

[0017]

As described above, the present invention can provide a method for preventing solder bridges between terminals, which can prevent solder bridges between terminals using an extremely simple method.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a method for preventing solder bridges between terminals according to an embodiment of the present invention;

FIG. 2 is a diagram for explaining the method of immersing a terminal in molten solder; FIG. 1 is a rear view of a package of a semiconductor device, and FIG. 10(c) is an enlarged side view of a main part of a semiconductor device in which a solder bridge has occurred.

[Explanation of symbols]

11 is a semiconductor device (electronic component), 11a is a package, 11b is a brazing pattern, 11c is a terminal, 12 is a bridge prevention plate, 12a is a Teflon sheet, 12b is an opening, 13 is a melting plate 14 represents a solder bridge, and 15 represents a solder melting tank.

Claims (1)

[Claims] Claim 1: Solder bridging prevention that prevents solder bridging that occurs between adjacent terminals when a plurality of rod-shaped terminals hanging vertically on the back surface of an electronic component package are simultaneously dipped into molten solder and pulled up. In the method,
Before immersing the terminals (11c) in the molten solder (13), the terminals (11c) are arranged on a sheet (12a) that can withstand the temperature of the molten solder (13) and does not allow the molten solder (13) to adhere. and connect the corresponding terminal (11c
) The bridge prevention plate (12) is provided with an opening (12b) approximately the same size as the thickness of the opening (12b).
The terminal (11c) is inserted into the package (
11a) A method for preventing solder bridging between terminals, characterized in that the terminal (11c) is immersed in the molten solder (13) in close contact with the back surface of the terminal.