JPH04359584A - Flat cable - Google Patents

Abstract

PURPOSE:To provide a flat cable which can absorb lateral deviation of a pad row and absorb a positional deviation between a pad and a conductor pattern and which has high reliability of connection in the cable for connecting a plurality of module components placed on a mother printed board to each other. CONSTITUTION:In a cable in which a plurality of conductor patterns 55 having predetermined characteristic impedances are formed in parallel with each other on a dielectric sheet 51, and a plurality of module components placed on a mother printed board are connected to each other by thermally press-bonding ends of the patterns 55 to pads arranged on a module board, both end closed slits 61 having nonslit lines 61A at both right and left ends of the cable, are formed between the patterns 55.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat cable that connects a plurality of module components mounted on a motherboard printed board.

[0002] With the demand for higher density and higher speed, printed board units in which a large number of module parts are mounted on a large motherboard printed board are being used in recent electronic devices.

FIG. 7 is a diagram of the above-mentioned printed board unit, in which (A) is a sectional view and (B) is a plan view of important parts. In FIG. 7, 2 is a module component in which a plurality of semiconductor chips 22 are sealed and mounted on a module substrate 21 such as a ceramic multilayer substrate, and 3 is also a module component in which a plurality of semiconductor chips 32 are mounted on a module substrate 31 such as a ceramic multilayer substrate. It is a module component that is sealed and mounted.

Reference numeral 1 denotes a motherboard printed board made of a large multilayer printed wiring board. Motherboard printed board 1
A plurality of the above-mentioned module components are mounted in close proximity and facing each other by inserting and soldering lead terminals into through holes.

[0005] In addition to the module parts 2 and 3, a circuit part 4 is also mounted on the motherboard printed board 1. In the printed board unit described above, when module parts are connected via lead terminals and patterns on the motherboard printed board, many patterns are provided on the motherboard printed board, and as a result, the printed board becomes large. In other words, there are problems that the number of layers is increased more than necessary, and that speeding up is hindered.

Therefore, as shown in FIG. 7B, the pads 25 are arranged on the side edge of the module substrate 21 of one module component 2, and the pads 25 are arranged on the side edge of the module substrate 31 of the other module component 3. This is solved by arranging opposing pads 35 on the edge and connecting these pads via a flat cable 5.

[0007]

2. Description of the Related Art FIG. 8 is a diagram of a conventional flat cable, in which (A) is a plan view and (B) is a sectional view.

The conventional flat cable 5 has a ground conductor layer 52 formed on the entire surface of one side of a heat-resistant strip-shaped dielectric sheet (for example, a polyimide resin sheet) having a predetermined thickness and a predetermined dielectric constant. A large number of parallel conductor patterns 55 are provided on the other side, and each conductor pattern 5
5 is a predetermined characteristic impedance.

The flat cable 5 has a protective resin layer 53 covering the surface of the ground conductor layer 52, and a conductor pattern 5.
The surface of 5 is covered with a protective resin layer 56 except for the left and right ends. The module components 2 and 3 are connected by attaching bumps 6 to both ends of the conductor pattern 55 of such a flat cable 5 and thermocompression bonding to the pads of the module board shown in FIG.

Since the module components are connected using such a flat cable 5, impedance mismatch is eliminated and there is almost no transmission loss. Furthermore, since the flat cable 5 is flexible, the connection can be made without any problem even if there is a height difference between both module boards.

[0011]

[Problems to be Solved by the Invention] By the way, conventional connection means using flat cables provide good results in absorbing deviations in pad rows due to differences in height of module boards, but problems arise due to lateral deviations between module components. There is a problem in that it is difficult to absorb the lateral displacement of the pad rows that occurs due to the pad rows.

On the other hand, as the number of pins of module components increases, manufacturing errors in the pad pitch of the module board and manufacturing errors in the conductor pattern pitch of the flat cable cause misalignment between the pads and the conductor pattern. There is a problem with that.

[0013] Furthermore, with conventional flat cables, if part of the conductor pattern becomes defective, or if it becomes necessary to shield part of the conductor pattern due to its characteristics, the entire flat cable must be replaced. There was a problem that it was not possible.

[0014] The present invention was created in view of these points, and can absorb lateral displacement of pad rows, and also absorbs positional displacement between pads and conductor patterns, resulting in high connection reliability. The purpose is to provide flat cables.

Another object is to provide a flat cable in which selected conductor patterns can be easily separated.

[0016]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method in which a plurality of conductor patterns 55 having a predetermined characteristic impedance are formed in parallel on a dielectric sheet 51, and pads arranged on a module substrate. By thermocompression bonding the ends of each of the conductor patterns 55 to A slit 61 with closed ends 61 having non-slit lines 61A at both ends thereof is formed between each conductor pattern 55.

Further, as illustrated in FIG. 3, a pair of one-end closed slits 62 having a non-slit line 62A are formed in the center of the cable between selected conductor patterns 55.

Furthermore, as illustrated in FIG. 4, a pair of one-end closed slits 62 having a non-slit line 62A are formed in the central portion of the cable through the selected conductor pattern 55.
At least two alignment holes 7 are formed between the
0 shall be provided on each of the left and right side edge portions of the flat cable 50.

As illustrated in FIG. 5, a pair of one-end closed slits 62 have a non-slit line 62A in the center.
are provided between the selected conductor patterns 55, and both-end closed slits 61 having non-slit lines 61A at both ends are provided between all the other conductor patterns 55.

On the other hand, as illustrated in FIG. 6, perforations 71 are provided in the non-slit lines 61A on the left and right of the slits 61 closed at both ends, and perforations 72 are provided in the non-slit lines 62A between the slits 62 closed at one end. do.

[0021]

[Operation] According to the present invention illustrated in FIG. 1, a slit 61 closed at both ends is provided between the conductor patterns of the flat cable.
The central part of the flat cable is separated into thin strips.

[0022] Therefore, lateral displacement between module parts can be absorbed without applying undue stress to the flat cable. According to the present invention illustrated in FIG. 3, a pair of one-end closed slits 62 having a non-slit line 62A in the central portion of the cable are provided between the selected conductor patterns 55.
The end of the flat cable 50 can be divided into two parts (in the case of one end closed slit) or three parts (in the case of one end closed slit).

Therefore, even if there is an error between the arrangement pitch of the conductor patterns and the arrangement pitch of the pads, the amount of positional deviation between each pad and each conductor pattern can be reduced.

Further, as shown in FIG. 4, a flat cable 50
By providing an alignment hole 70 on the module board side and providing a pin into which the alignment hole 70 is inserted on the module board side, positioning during the bonding work between the module component and the flat cable becomes easy.

As illustrated in FIG. 5, by using the slits closed at both ends and the slits closed at one end, it is possible to absorb lateral displacement between module components and to reduce the difference between the conductor pattern arrangement pitch and the pad arrangement pitch. can absorb errors.

On the other hand, as illustrated in FIG. 6, by providing perforations 71 on the left and right non-slit lines 61A of the both-end closed slits 61, and providing perforations 72 on the non-slit lines 62A between the one-end closed slits 62, By cutting out this perforation, an arbitrary conductor pattern 55 can be formed.
Easy to separate from flat cable.

[0027] Therefore, it is not necessary to replace the entire flat cable when a part of the conductor pattern becomes defective or when it becomes necessary to particularly shield a part of the conductor pattern due to its characteristics.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings. Note that the same reference numerals indicate the same objects throughout the figures.

FIG. 1 is a diagram of an embodiment of the first invention, (A)
is a plan view of the front side, (B) a plan view of the back side, (C)
is a sectional view, and FIG. 2 is a diagram showing the mounting state of the present invention.
) is a cross-sectional view of the printed board unit, and (B) is a cross-sectional view of key points.

FIG. 3 is a plan view of an embodiment of the second invention, and FIG.
is a plan view of an embodiment of the third invention, FIG. 5 is a plan view of an embodiment of the fourth invention, and FIG. 6 is a plan view of an embodiment of the fifth invention.

In FIG. 1, the flat cable 50 is
A ground conductor layer 52 is formed on the entire surface of one side of a heat-resistant belt-shaped dielectric sheet (for example, a polyimide resin sheet) with a predetermined thickness and a predetermined dielectric constant, and a large number of parallel conductor patterns are formed on the other side. 55, and each conductor pattern 55 has a predetermined characteristic impedance (for example, 50Ω).

The surface of the ground conductor layer 52 is covered with a protective resin layer 53, and the surface of the conductor pattern 55 is covered with a protective resin layer 56 except for the left and right ends. Further, each conductor pattern 55 is provided with a slit 61 with closed ends 61 having non-slit lines 61A at both left and right end portions of the flat cable 50.

Incidentally, bumps 6 such as solder bumps, for example, are attached to both ends of each conductor pattern 55, and thermocompression bonded via the bumps 6 to a pad of a module component to be described later.

On the other hand, as shown in FIG. 2, the printed board unit is a module constructed by mounting a plurality of semiconductor chips 22 on a module board 21 in a sealed manner on a motherboard printed board 1 made of a large multilayer printed wiring board. Part 2
and a module component 3 configured by sealingly mounting a plurality of semiconductor chips 32 on a module substrate 31 such as a ceramic multilayer substrate are mounted facing each other.

Module board 2 of this module component 2
1, a large number of pads 25 are arranged close to each other in a horizontal row at an equal pitch on the upper part near the side edge of the module board 21. Also, the module board 31 of the other module component 3
Pads (not shown) are arranged in a horizontal row close to each other at equal pitches on the upper surface of the opposing side edges of the module component 2, facing the pads 25 of the module component 2.

The above-described flat cable 50 is constructed by aligning the left and right ends of the conductor pattern 55 with the corresponding pads, bridging between the module parts 2 and 3, and bonding the bumps 6 by thermocompression. It is connected to the pad through.

Since each conductor pattern 55 has a predetermined characteristic impedance, there is no impedance mismatch between the module components and the flat cable. Furthermore, since the flat cable 50 is flexible, the connection can be made without any problem even if there is a height difference between both module boards.

Furthermore, by providing the slits 61 closed at both ends, lateral displacement of the pad rows caused by lateral displacement between module components can be easily absorbed. In FIG. 3, a flat cable 50 has a large number of parallel conductor patterns 55 each having a predetermined characteristic impedance.

A pair of one-end closed slits 62 are provided between the two conductor patterns 55 provided near the center line by cutting from both ends of the flat cable in the longitudinal direction.

That is, the pair of one-end closed slits 62 are formed in a straight line on both sides of the central non-slit line 62A. flat cable 5 as mentioned above
0, the center portion is connected by a non-slit line 62A portion, and both end portions are separated by an end-closed slit 62.

Therefore, by aligning the end of the conductor pattern 55 close to the side edge of the flat cable 50 with the end pad disposed on the corresponding module board, the arrangement pitch of the conductor pattern 55 and the pads can be adjusted. Manufacturing errors with respect to the arrangement pitch can be absorbed, and the amount of positional deviation between individual pads and individual conductor patterns is reduced.

In FIG. 4, a pair of one-end closed slits 62 having non-slit lines 62A are formed in the central portion of the cable between selected conductor patterns 55, and dielectric sheet 51 portions at four corners of the flat cable 50 are formed. A positioning hole 70 is drilled in each.

On the other hand, although not shown, a pin into which the alignment hole 70 is inserted is provided on the module board side. Therefore, it becomes extremely easy to position the module component and the flat cable during the joining operation.

The flat cable 50 shown in FIG.
A pair of one-end closed slits 62 having a non-slit line 62A in the central portion are provided between the two conductor patterns 55 provided near the center line, and both-end closed slits 61 each have a non-slit line 61A in both end portions.
are provided between all the other conductor patterns 55.

Therefore, not only can the lateral displacement of the pad rows caused by the lateral displacement between the module components be easily absorbed, but also the amount of positional displacement between the individual pads and the individual conductor patterns can be reduced. can.

The flat cable 50 shown in FIG.
A pair of one-end closed slits 62 having a non-slit line 62A in the central portion are provided between the two conductor patterns 55 provided near the center line, and both-end closed slits 61 each have a non-slit line 61A in both end portions.
are provided between all the other conductor patterns 55.

[0047] Perforations 71 are provided on the left and right non-slit lines 61A of the both-end closed slits 61, and
A perforation 72 is provided in the non-slit line 62A between the slits 62 that are closed at one end.

Therefore, the flat cable 50 shown in FIG. 6 can easily absorb the lateral displacement of the pad rows caused by the lateral displacement between the module components, and can easily absorb the lateral displacement of the pad rows caused by the lateral displacement between the module components. In addition to reducing the amount of positional deviation between the perforations 71 and 71, it is possible to
Alternatively, by cutting the perforations 72, any conductor pattern 55 can be separated from the flat cable.

That is, it is not necessary to replace the entire flat cable when a part of the conductor pattern becomes defective or when it becomes necessary to particularly shield a part of the conductor pattern due to its characteristics.

[0050]

[Effects of the Invention] As explained above, the present invention uses a flat cable in which conductor patterns having a predetermined characteristic impedance are arranged and has closed slits at both ends to connect opposing module components without impedance mismatch. be able to.

[0051] Further, it has the effect that it is easy to absorb positional deviations due to differences in height between module parts and to absorb lateral deviations between module parts. In addition, by providing a closed slit at one end, even if there is an error between the arrangement pitch of the conductor pattern of the flat cable and the arrangement pitch of the pads on the module component side, the amount of positional deviation between each pad and each conductor pattern can be reduced. can be made smaller.

Furthermore, by providing the alignment holes, positioning of the module components and the flat cable during the bonding work is facilitated. On the other hand, by providing perforations on the non-slit lines on the left and right of the slits closed at both ends, and other perforations on the non-slit lines between the slits closed at one end, in addition to the above-mentioned effects, part of the conductor pattern may become defective. This has an excellent effect in that it is not necessary to replace the entire flat cable in cases where a part of the conductor pattern needs to be particularly shielded due to its characteristics.

[Brief explanation of the drawing]

[Fig. 1] Diagrams of the embodiment of the first invention, (A) is a plan view of the front side (B) is a plan view of the back side (C) is a sectional view

[Fig. 2] A diagram showing the mounting state of the present invention, in which (A) is a cross-sectional view of the printed board unit and (B) is a cross-sectional view of key points.

[Figure 3] Plan view of the embodiment of the second invention

[Figure 4]
A plan view of an embodiment of the third invention

[Fig. 5] Plan view of the embodiment of the fourth invention

[Fig. 6] Plan view of the embodiment of the fifth invention

[Figure 7] Diagram of the printed board unit, where (A) is a sectional view and (B) is a plan view of key points.

[Figure 8] A diagram of a conventional flat cable, (A)
is a plan view (B) is a cross-sectional view

[Explanation of symbols]

1 motherboard printed board,
2,3 Module parts 5,50 Flat cable,
21, 31 module board, 22, 32 semiconductor chip,
25, 35 pad, 51 dielectric sheet,
52 earth conductor layer, 55 conductor pattern,
53, 56 Protective resin layer, 61 Closed slits at both ends,
62 one end closed slit, 70 alignment hole,
71, 72 perforation,

Claims (5)

[Claims] 1. A plurality of conductor patterns (55) having a predetermined characteristic impedance are formed in parallel on a dielectric sheet (51), and the ends of each conductor pattern (55) are connected to pads arranged on a module substrate. A cable that connects multiple module components mounted on a motherboard printed board by thermocompression bonding, and has non-slit lines (61A) at both left and right ends of the cable.
A slit (61) with closed ends (61) has a conductor pattern (
55) A flat cable characterized by being formed between. [Claim 2] A pair of one-end closed slits (62) with a non-slit line (62A) in the central portion of the cable.
is formed between selected conductor patterns (55). 3. At least two alignment holes (70)
3. The flat cable according to claim 2, wherein: is formed on each of the left and right side edge portions of the cable. [Claim 4] A non-slit line (62A
) is formed between the selected conductor patterns (55), and a pair of closed-end slits (61) having non-slit lines (61A) at both ends are formed between the other conductor patterns ( 55) A flat cable characterized by being formed between. [Claim 5] A perforation (71) is provided on the left and right non-slit lines (61A) of the slit (61) closed at both ends, and a non-slit line (62A) between the slit (62) closed at one end.
5. The flat cable according to claim 1, wherein a perforation (72) is formed in the flat cable.