JPH0645376U - Printed circuit board for mounting integrated circuits - Google Patents

Abstract

(57) [Abstract] [Purpose] In the conventional printed circuit board, the bridge between terminals at the time of soldering increases with the increase in the density and the number of terminals of the integrated circuit, which makes inspection and correction complicated. However, there is a problem in that it deteriorates productivity. According to the present invention, the integrated circuit 10 of the land 2a corresponds to the terminal 11 which does not require connection, but the surface of the integrated circuit 10 is covered with the solder resist 3 to form the printed circuit board 1 for mounting the integrated circuit. Even when mounting a recent integrated circuit that is supposed to approach, it is possible to reduce the absolute number of solder bridges generated, specify the location where the solder bridges occur, and simplify the inspection and correction processes, thereby solving the problem.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a printed circuit board on which electronic parts are mounted and wiring is performed. Specifically, the present invention relates to a printed circuit board provided with a large number of lands aligned at a constant pitch for the purpose of mounting an integrated circuit. Is.

[0002]

[Prior art]

 FIG. 3 shows an example of the structure of a conventional printed circuit board 90 of this type. The printed circuit board 90 is provided in the integrated circuit 80 in order to mount the integrated circuit 80 and fix it at a predetermined position and to make electrical connection. The lands 91a corresponding to the terminals 81 are aligned at a predetermined pitch such as a 1/20 inch to form an IC pattern 91, and each land 91a of the IC pattern 91 is coated with cream solder. As described above, soldering is said to be performed by passing the integrated circuit 80 through a reflow furnace with the integrated circuit 80 mounted. Although not shown, a solder resist is applied to a portion of the printed circuit board 90 which does not require soldering.

[0003]

[Problems to be solved by the device]

 In recent years, the degree of integration of the integrated circuit 80 has been improved more and more, and the number of terminals 81 has been increasing, and along with this, the pitch between the terminals 81 tends to be narrowed. However, in the above-described conventional printed circuit board 90, as the pitch is narrowed, the occurrence of the blitches B between the terminals 81 due to the surface tension of the solder increases. For example, the terminals 81 pass through the reflow furnace. Since visual inspection and manual correction work were required during this period, there was a problem that hindered productivity, and the solution of this problem became an issue.

[0004]

[Means for Solving the Problems]

 As a concrete means for solving the above-mentioned conventional problems, the present invention provides a printed circuit board for mounting an integrated circuit in which a plurality of lands are arranged at a constant pitch for mounting an integrated circuit. By providing a printed circuit board for mounting an integrated circuit characterized in that the surface of the integrated circuit corresponding to the terminals that do not require connection is covered with a solder resist, the possibility of solder bridges is reduced. To solve the problem.

[0005]

【Example】

 Next, the present invention will be described in detail based on an embodiment shown in the drawings. Reference numeral 1 in FIGS. 1 and 2 denotes a printed circuit board. On the board surface of the printed circuit board 1, lands 2a corresponding to the pitch and the number of terminals 11 of the integrated circuit 10 are arranged and the IC pattern 2 is formed. However, according to the present invention, the terminal 11 of the integrated circuit 10 is not connected to the internal circuit labeled NC, for example, or No connection is required for the purpose of using the printed circuit board 1, that is, the surface of the land 2a corresponding to the unused terminal 11 is covered with the solder resist 3 so that the solder does not adhere. ing.

Here, the background of the present invention will be described. Of course, the same result can be obtained by erasing unnecessary land 2a in order to obtain the same operation and effect as the purpose of the present invention. Will be obtained. However, when actually forming the IC pattern 2 on the printed circuit board 1, a master negative (or a master positive) is prepared as a standard for each type of package of the integrated circuit 10 to be used, and the master substrate (or master positive) is used to form the printed circuit board 1. The required IC pattern 2 is formed at a predetermined position on the photographic document by being transferred from the master negative.

Therefore, specifying and erasing the unnecessary lands 2a for each individual case is extremely complicated in actual practice, and therefore, in the present invention, each individual printed board 1 is originally designed. By using the solder resist plate for plate making and covering the land 2a of the unnecessary portion with the solder resist 3, it is possible to obtain the same operation and effect as that of erasing, assuming that the land 2a does not substantially exist. I'm supposed to get it.

Next, the operation and effect of the present invention configured as described above will be described. By covering the land 2a of the unnecessary portion with the solder resist 3, the terminal 11 which is not soldered is formed. 11 exists, and during this time, the same action as that when the distance between the terminals 11 is widened occurs, and the solder bridge does not occur.

This means that as the absolute number of solder bridges is reduced and the places where they do not occur are specified, the inspection of that portion can be omitted. For example, inspection and correction after passing through the reflow furnace. The process can be simplified.

As a result of a research conducted by the inventor of the present invention, specifically, in a circuit in which the accumulation circuit 10 of this type is used, about 1/4 to 1/3 of the terminals 11 are not included. In some cases, it was confirmed that the above configuration worked extremely effectively.

[0011]

[Effect of device]

 As described above, according to the present invention, the integrated circuit of the land corresponds to the terminals that do not require connection, but the surface of the integrated circuit is covered with the solder resist. Even when mounting a recent integrated circuit that is supposed to approach, it is possible to reduce the absolute number of solder bridges generated and to specify the location where they occur, thereby simplifying the inspection and repair processes. As a result, it is extremely effective in improving the production efficiency of this type of printed circuit board assembly process.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a printed circuit board for mounting an integrated circuit according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a perspective view showing a conventional example.

[Explanation of symbols]

 1 ... Printed circuit board 2 ... IC pattern 2a ... Land 3 ... Solder resist 10 ... Integrated circuit 11 ... Terminal

Claims (1)

[Scope of utility model registration request] 1. A printed circuit board for mounting an integrated circuit, comprising a plurality of lands arranged at a constant pitch for mounting an integrated circuit, wherein the land of the integrated circuit corresponding to a terminal that does not require connection is soldered. A printed circuit board for mounting an integrated circuit, which is covered with a resist.