JP3008887U - IC pitch conversion board - Google Patents

Abstract

(57) [Abstract] [Purpose] An IC pitch conversion board having a conductor pattern for connecting the lead terminals of the IC on the front surface and a plurality of connection pins for connecting to the main circuit board on the back surface is made as small as possible and the IC pitch is It is an object of the present invention to provide an IC pitch conversion board that minimizes the ineffective area of the main circuit board occupied by the conversion board. A conductor pattern for connecting a lead terminal 5 of an IC is formed on a surface of a multilayer substrate 1, and the conductor pattern is connected to a through hole for pin insertion through a common through hole and an inner layer pattern of the multilayer substrate, and the pin It is characterized in that connection pins are set up in the insertion through holes and the tips of the pins are projected to the back surface of the multilayer substrate.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention is an IC pin that is interposed between the IC and the main circuit board to expand the IC pin interval to the pin interval of the main circuit board for connection in response to high integration and high pin count of the IC. H conversion substrate.

[0002]

[Prior art]

 Recently, in highly integrated ICs, a lead terminal is horizontally projected from the outer periphery of the package, and is further formed by bending it into a GALL-WING shape, and a QFP type IC that inputs and outputs a power supply and a signal through the lead terminal, or A PLCC type IC in which the lead terminal is bent downward and then folded back inward to reduce the area occupied by the IC is often used. As the degree of integration increases, the IC chip size decreases, the number of input / output signal lead terminals increases, the spacing between conductor patterns formed on the main circuit board also decreases, and the lead patterns extracted from the conductor patterns are reduced. Is also narrowing. Therefore, when the IC is directly soldered to the main circuit board, problems such as short circuit due to solder, circuit pattern disconnection and pattern peeling occur, and routing of other circuit patterns is also restricted. Further, since the number of lead patterns passing between the pins of the IC is limited, the main circuit board must be multi-layered to mount such an IC. Furthermore, in order to support the dimensional accuracy of the conductor pattern and the thermal stability of the conductor pattern, the main circuit board must be formed of an expensive glass epoxy laminated plate, which is one of the reasons for the high cost.

Conventionally, as a countermeasure against this, an IC pitch conversion substrate composed of a two-layer printed circuit board is interposed between the IC and the main circuit board. As an example, the front surface of the IC pitch conversion substrate 1 is shown in FIG. 8 and the back surface is shown in FIG. On the surface of the IC pitch conversion substrate 1, a plurality of conductor patterns 2 are arranged along the four sides of the quadrangle so as to match the plurality of lead terminals 11 a of the IC 11 (FIG. 10). Then, a plurality of through holes 4 for inserting pins are formed in a grid pattern (in this example, 4 rows and 13 columns) outside the conductor pattern 2 at a predetermined interval. Next, lead patterns 3 are formed on the front surface of the board from the conductor pattern 2 toward the through holes 4 for inserting pins, or a signal path is formed on the back surface of the board through the through holes 13 to form leads on the back surface of the board. The pattern 3 is extended to a predetermined pin insertion through hole 4 for connection, and the connection pin 5 is set in the pin insertion through hole 4, and the connection pin 5 is inserted into a main circuit board (not shown). The pin insertion through-holes 4 are formed adjacent to each other so that at least two lead patterns 3 can pass therethrough. Then, the lead pattern 3 is pulled out from the first conductor pattern 2 from the left end of the upper side of the quadrangle to the inside of the conductor pattern 2 arranged in a quadrangle, and the through hole 13a and the land are formed at the tip of this lead pattern 3, and the through hole is formed. A lead pattern 3a is formed from 13a to the back surface of the substrate and connected to the pin insertion through hole 4a in the outermost peripheral row.

Next, the second conductor pattern 2b is attached to the pin insertion through hole 4b by the lead pattern 3, the third conductor pattern 2c is attached to the pin insertion through hole 4c by the lead pattern 3, and the fourth conductor pattern 2d is attached. The lead patterns 3 are connected to the innermost pin insertion through holes 4d, respectively. Similarly, every four sets of the conductor patterns 2 are connected to the corresponding through holes 4 for pin insertion, and the lead terminals 11a of the IC are inserted through the conductor patterns 2, the through holes 13 and the lead patterns 3 for pin insertion. Connect to the through hole 4. This widens the space between the lead patterns 3 and the width of the lead patterns 3 to prevent problems such as short circuit between the lead patterns 3 due to soldering, disconnection of the lead patterns 3 and peeling of the pattern.

However, in this conventional example, since many pin insertion through holes 4 are formed outside the package of the IC 11, the size of the IC pitch conversion substrate 1 becomes large as shown in FIG. The same area is required for the main circuit board on which the pitch conversion board 1 is mounted, which is an obstacle to the cost reduction of the IC pitch conversion board 1 and the downsizing of the main circuit board.

[0006]

[Problems to be solved by the device]

 In order to solve the above problems, it is an object of the present invention to make the width and interval of the lead pattern of the IC pitch conversion board wide and to make the size of the IC pitch conversion board as small as possible.

[0007]

[Means for solving the problem]

 In order to achieve the above object, the present invention forms a conductor pattern for connecting a lead terminal of an IC on a surface of a multi-layer board, and the conductor pattern is a through hole for inserting a pin through a common through hole of the multi-layer board and an inner layer pattern. Connection pins were set up in the through holes for pin insertion, and the tips of the pins were projected to the back surface of the multilayer substrate.

[0008]

[Action]

 With the above configuration, the signal paths from the plurality of conductor patterns corresponding to the plurality of leads of the IC to the plurality of connection pins are separately arranged in each layer through the through holes and the inner layer patterns of the multilayer board. , The pattern pitch of each signal path is expanded through the insulating layer to secure a sufficient insulation interval, and the multiple IC pins are placed on the back side of the IC mounting surface and on the outer side of the IC mounting surface to divide the IC pitch. The size of the conversion board can be reduced, and at the same time, the ineffective area of the main circuit board by the IC pitch conversion board can be reduced, so that the main circuit board can be effectively used.

[0009]

【Example】

 Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view of an IC pitch conversion substrate according to an embodiment of the present invention, showing its front side, and FIG. 2 shows its back side. The IC pitch conversion board 1 is composed of a 4-layer laminated circuit board, and the conductor pattern 2 is formed on the surface of the board on which the ICs are mounted along the 34 quadrangles corresponding to the 136P PLCC. Further, on the outer side of the conductor pattern 2, a total of 52 through holes 4 for pin insertion are formed along the outer edge of the substrate, 13 on each side. G is a through hole for ground. Eighty-four common through holes 6 and ground through holes G are formed inside the conductor pattern 2 (that is, a portion that contacts the bottom surface of the IC package). The pin insertion through hole 4, the common through hole 6 and the G ground through hole pass through the layers of the laminated circuit board.

On the back surface of the IC pitch conversion substrate 1, the above-described 84 common through holes 6 and 52 pin insertion through holes 4 penetrate through. Inside the 52 through holes 4 for pin insertion, a total of 84 through holes 44 (blinds) for 21 pins are formed in two rows on each side, for a total of 136 pin insertion holes. Insert the connection pins 5 into the through holes 4 and 44 and plant them. Here, the inner ends of the connection pins 5 do not reach the surface of the substrate 1 as shown in FIG. The through hole 44 for pin insertion is formed by forming a through hole at a predetermined position on the second substrate before laminating and adhering, and in this state, the through hole 4 for pin insertion is formed by through hole plating. A blind through hole is formed by laminating and adhering to the substrate.

FIG. 3 is a side view showing a state in which the IC (PLCC) 11 is mounted on the IC pitch conversion board 1, and the connection pin 5 fits in an area almost the same as the size of the IC 11 (PLCC). 1, the area occupied by the board when mounted on the main circuit board (not shown) can be reduced.

FIG. 4 is an enlarged cross-sectional view showing a laminated state of the IC pitch conversion substrate of the present invention. This substrate is the first conductor layer L1, the glass epoxy resin layer 7 and the second conductor in this order from the component side of the surface. The first laminated plate composed of the layer L2, the third conductive layer L3, the glass epoxy resin base material 10, and the second laminated plate composed of the fourth conductive layer L4 are used as the insulating plate 9 and the bonding sheet 12 by the prepreg layer 8. It is constructed by laminating and bonding via.

FIG. 5 is an enlarged cross-sectional view of an essential part of the IC pitch conversion substrate 1. In the first laminated plate and the second laminated plate, a predetermined circuit pattern is formed for each conductor layer by etching, and then the prepreg layer is formed. 8 is laminated and adhered. After bonding, an insulating coating (resist) is applied on the entire surface except the conductor pattern 2 of the first layer L1. In the state where they are laminated and adhered, a plurality of holes for common through holes are formed in the central part of the board and a plurality of holes for through holes for pin insertion are formed in the peripheral part, and the common through holes 6 and the pins are formed by through hole plating. The through hole 4 for insertion is formed. The common through-hole 6 is formed by forming a conductor land at a predetermined position on each conductor layer in advance before the through-hole plating. Then, through-hole plating is performed through the conductor land to form a surely connected conductor layer in the through hole. On the surface of the first conductor layer L1, the conductor pattern 2, the lead pattern 3 connected to the conductor pattern 2, and the land of the common through hole 6 are formed.

Different examples of the connecting method from the conductor pattern 2 to the connecting pin 5 are shown in section a and section b in FIG. 5, and these will be described below. In the section a, the conductor pattern 2a is connected to the common through hole 6a via the lead pattern 3a. Then, the second conductor layer L2 of the common through hole 6a is connected to the common through hole 6aa via the lead pattern 3aa, and further, the third conductor layer L3 of the common through hole 6aa is connected to the pin insertion through hole 4a via the lead pattern 3aa. To do. The connection pin 5a is in close contact with the conductor coating on the inner periphery of the through hole 4a for pin insertion and is connected thereto. In the section b, the conductor pattern 2b is connected to the common through hole 6b through the lead pattern 3b, the third conductor layer L3 of the common through hole 6b is connected to the lead pattern 3bb, and the conductor on the side surface of the pin insertion through hole 4b is further connected. Connect to the connecting pin 5b through the coating. The pin insertion through hole 4 on the outer edge is directly connected to the pin insertion through hole 4 by the lead pattern 3 of the first layer from the conductor pattern 2 instead of the above connection method.

As described above, a multi-layer printed wiring board having four or more layers is used for the IC pitch conversion board 1, and the connection pattern 5 is connected to the connection pin 5, so that the connection pin 5 is connected to the IC mounting surface of the board 1. It can also be arranged on the back surface, and the size of the IC pitch conversion substrate 1 can be reduced, and the mounting area of the main circuit substrate can also be reduced.

FIGS. 6 and 7 show an embodiment in which the connection pins 5 are arranged on the back surface of the IC mounting surface of the substrate 1 as described above. FIG. 6 shows a 96-pin QFP-IC on the IC pitch conversion substrate 1. FIG. 7 shows a side view of the mounted state, and FIG. A four-layer laminated substrate is used for the IC pitch conversion substrate 1, and the conductor pattern 2 and the connecting pin 5 are connected to each layer of the laminated substrate by a common through hole, thereby providing the connection pins 5 in close proximity to each other. As shown in FIG. 7, the pins are concentrated on the back surface of the IC mounting surface, whereby the IC pitch conversion substrate 1 can be made small, and the size can be made almost close to the external dimensions of the IC.

[0017]

[Effect of device]

 As described above, in the present invention, the multi-layer substrate is used as the IC pitch conversion substrate, and the conductor pattern for soldering the lead terminal of the IC is formed on the common through hole of the multi-layer substrate and the through hole for pin insertion through the inner layer pattern. By connecting and connecting to the main circuit board by connecting pins set up in the through holes for insertion, the mutual space between the connecting pins is narrowed, the size of the IC pitch conversion board is reduced, and the IC mounting area of the main circuit board is reduced. Can be reduced to reduce the total cost. In addition, when repairing the main circuit board with the IC entangled, you can easily replace the IC on the spot by unsoldering the connection pins of the IC pitch conversion board and replacing the IC pitch conversion board. Workability can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of an IC pitch conversion substrate according to an embodiment of the present invention.

FIG. 2 is a bottom view of an IC pitch conversion board according to an embodiment of the present invention.

FIG. 3 is a side view showing a state in which an IC is mounted on the IC pitch conversion substrate of the embodiment of the present invention.

FIG. 4 is an enlarged sectional view showing a laminated structure of an IC pitch conversion substrate according to an embodiment of the present invention.

FIG. 5 is an enlarged sectional view of an essential part of an IC pitch conversion board according to an embodiment of the present invention.

FIG. 6 shows an IC pitch conversion board according to another embodiment of the present invention.
It is a side view of a state where C is mounted.

7 is a bottom view of the IC pitch conversion substrate of FIG.

FIG. 8 is a plan view of a conventional IC pitch conversion substrate.

FIG. 9 is a bottom view of a conventional IC pitch conversion substrate.

FIG. 10 is a side view showing a state in which an IC is mounted on a conventional IC pitch conversion substrate.

[Explanation of symbols]

 1 IC Pitch Conversion Board 2 Conductor Pattern 3 Lead Pattern 4 Through Hole for Inserting Pin 5 Connection Pin 6 Common Through Hole 7 Glass Epoxy Resin Layer 8 Prepreg Layer 9 Insulating Plate 10 Glass Epoxy Resin Base Material 11 IC 12 Bonding Sheet 13 Through Hole L1 1st conductor layer L2 2nd conductor layer L3 3rd conductor layer L4 4th conductor layer

Claims (1)

[Scope of utility model registration request] 1. A conductor pattern for connecting a lead terminal of an IC is formed on a surface of a multi-layer substrate, and the conductor pattern is connected to a through hole for pin insertion through a common through hole and an inner layer pattern of the multi-layer substrate to form the pin. An IC pitch conversion board in which connection pins are set up in the through holes for insertion and the tips of the pins are projected on the back surface of the multilayer board.