JP2001358290A - Surface mounting lsi package, surface mounting package board surface mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface mounting LSI package, a surface mounting package board and a surface mounting method, in which the length of electric wiring is shortened and the number of layers is decreased. SOLUTION: In surface mounting package board for mounting LSI packages having an identical function and line symmetric pin arrangement, the LSI packages are mounted mirror symmetrically on the surface of the package board and at positions on the backside immediately thereunder. Pads of the LSI package on the surface side are connected with pads of the LSI package on the backside through through holes such that the length L of electric wiring is shortened closely to the thickness of the package board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an LS for surface mounting.
The present invention relates to a surface mounting technology for an I package or a surface mounting package substrate, and particularly relates to a surface mounting LSI package for mounting an LSI package on a surface of a package substrate of a computer or other electronic device, a surface mounting package substrate, and It relates to a surface mounting method.

[0002]

2. Description of the Related Art In a conventional LSI package, an LSI package having substantially the same pin arrangement for one logic is prepared. Although there are differences in the type of LSI package, almost one mounting method is adopted. I have.

FIG. 6 shows an LS having outer leads 14.
FIG. 5 is a connection diagram for explaining a method of mounting an I package. In FIG. 6, 7 is a package substrate, 13 is a solder portion on the package substrate 7, 14 is an outer lead, 1
Reference numeral 5 denotes an LSI package.

[0004] A solder portion 13 is formed on the package substrate 7, and an LSI package 15 whose lead portion is bent like an outer lead 14 is attached to the package substrate 7.
A method of mounting on the upper solder portion 13 and connecting by reflow processing is adopted.

[0005]

However, in the conventional LSI package 15, the L
The problem with the structure of the SI package 15 is that the same LS
When a plurality of I packages 15 are mounted on the package substrate 7, only the same pattern can be mounted.

FIG. 7 shows a conventional LSI package 15.
It is a board | substrate side view which shows the state which mounted (1, 2) on both surfaces of the package board. In FIG. 7, 1 and 2 are LSI packages, 3 and 4 are outer leads, 5 and 6 are electric wiring,
Reference numeral 7 denotes a package substrate.

As shown in FIG. 7, in a conventional LSI package 15 (1, 2), an LSI package 1 (15) and an
When (15) is used and mounted at the position directly below the front surface and the back surface of the package substrate 7, the electrical wires 5 and 6 electrically connect the outer leads 3 and the outer leads 4 which are logically the same. Even if the wiring length is the shortest, the wiring length is diagonal as shown in FIG. 7 and the electric wiring 5 and the electric wiring 6 intersect. Therefore, in order to avoid the crossing of the electric wiring, there is a problem that the electric wiring must be performed in a different layer of the package substrate 7 or the electric wiring length must be increased.

FIG. 8 shows a conventional LSI package 15.
It is a board | substrate top view which shows the state which mounted (1, 2) on one surface of the package substrate. In FIG. 8, L indicates an electric wiring length.

Further, in the conventional LSI package 15, as shown in FIG. 8 (a), the same LSI package 15 (LSI package 1 (15) and LSI package 2) is used.
When (15) is used to mount the package on one side of the package substrate 7, the electrical wires 5 and 6 that logically connect the outer leads 3 and the outer leads 4 cross each other, and the package substrate 7 It is necessary to perform electrical wiring in different layers, and the number of layers must be increased.

[0010] As shown in FIG. 8B, the LSI package 1 is arranged so that the electric wiring 5 and the electric wiring 6 do not cross each other.
Even if 5 (1, 2) is mounted, there is a problem that the electric wiring length L becomes long.

As described above, the conventional LSI package 1
In No. 5, the number of layers of the package substrate 7 is increased in order to avoid the intersection of the electric wiring, an extra electric wiring length L is taken, which causes noise on the package substrate 7 or causes There was a problem that manufacturing became complicated.

The present invention has been made in view of such a problem, and an object of the present invention is to reduce the length of an electric wiring and reduce the number of layers by using an L for surface mounting.
An object of the present invention is to provide an SI package, a package substrate for surface mounting, and a surface mounting method.

[0013]

According to a first aspect of the present invention, there is provided an LSI package for surface mounting having outer leads, wherein all of the outer leads are arranged in one of an upper side and a lower side. An LSI package for surface mounting, characterized in that it is bent in the same direction and has a structure in which only the pin arrangement is line-symmetrical to each other with the same function. Further, the gist of the invention described in claim 2 of the present invention is a surface mounting package board for mounting an LSI package having the same function and only the pin arrangement is line-symmetric with each other, wherein the LSI package is The LSI is mounted on the surface of the package substrate and at a position directly below the back surface thereof so as to be mirror-symmetrical to each other.
A surface mounting structure characterized by having a structure in which a pad of the package and a pad of the LSI package on the back side are connected by through holes so as to shorten an electric wiring length to a thickness close to the thickness of the package substrate. Exists on the package substrate. The gist of the invention described in claim 3 of the present invention resides in a surface having a structure in which all the outer leads are bent in one of the upper and lower directions, and only the pin arrangement is line-symmetrical to each other with the same function. The mounting type LSI package is mounted at a position directly below the front surface and the back surface of the package substrate so as to be mirror-symmetrical with respect to the package substrate, respectively.
3. The structure according to claim 2, wherein a pad of the SI package and a pad of the LSI package on the back side are connected by through holes so as to reduce an electric wiring length to near the thickness of the package substrate. In the package substrate for surface mounting described in (1). The gist of the invention described in claim 4 of the present invention resides in that an LSI package having a pin arrangement for surface mounting on a package substrate and an LSI package having a pin arrangement for mounting on a back surface of the package substrate are arranged on one surface of the package substrate. When mounting, the LSI package has a structure in which electrical wirings for connecting logically the same pins of each of the LSI packages are arranged in the same layer of the package substrate without intersecting with each other. In the package substrate. The gist of the invention described in claim 5 of the present invention resides in that the surface mounting pin arrangement of the package substrate is provided, and all the outer leads are bent in one of the upper and lower directions and have the same function. It has an LSI package and a pin arrangement for mounting on the back side of the package substrate, which are only symmetrical to each other. All the outer leads are bent upward or downward in one direction, and only the pin arrangement is symmetrical to each other with the same function. When the LSI package is mounted on one side of the package substrate side by side, electrical wiring connecting logically the same pins of the LSI package is arranged in the same layer of the package substrate without crossing. The package substrate for surface mounting according to claim 4, wherein the package substrate has a provided structure. The gist of the invention described in claim 6 of the present invention is that all of the outer leads of a surface mounting LSI package having outer leads are bent upward or downward in one direction, and only the pin arrangement is performed with the same function. Has a step of forming an LSI package for surface mounting using a structure which is line-symmetric with respect to each other. The gist of the invention described in claim 7 of the present invention is a surface mounting method for producing a package substrate for surface mounting for mounting an LSI package having the same function and only the pin arrangement being line-symmetric with each other. The LSI package is mounted on the surface of the package substrate and directly below the back surface thereof so as to be mirror-symmetrical to each other.
Create a surface mount package board with a structure in which through-holes are connected between the package pads and the LSI package pads on the back side to reduce the electrical wiring length to near the thickness of the package board. A surface mounting method characterized by having a step of performing Also,
The gist of the invention described in claim 8 of the present invention is that a surface mount type having a structure in which all the outer leads are bent in one of the upper and lower directions, and only the pin arrangement is line-symmetric with each other with the same function. The above-mentioned LSI package is mounted at a position directly below the front surface and the back surface of the package substrate so as to be mirror symmetric with respect to the package substrate, respectively, and the LSI package pad on the front surface and the back surface A step of producing a surface mounting package substrate having a structure in which through-holes are connected between the pads of the LSI package and the electric wiring length to be close to the thickness of the package substrate. A surface mounting method according to claim 7. According to a ninth aspect of the present invention, there is provided an LSI package having a pin arrangement for surface mounting of a package substrate and an LSI package having a pin arrangement for rear surface mounting of a package substrate.
When the I package is mounted on one side of the package substrate and mounted, electric wiring for connecting logically the same pins of each of the LSI packages is arranged in the same layer of the package substrate without crossing. And a step of producing a surface mounting package substrate. The gist of the invention described in claim 10 of the present invention resides in that the surface mounting pin arrangement of the package substrate is provided, and all the outer leads are bent in any one of the upper and lower directions and have the same function. It has an LSI package and a pin arrangement for mounting on the back side of the package substrate, where only the arrangement is line-symmetric with each other. When the LSI package is mounted on one side of the package substrate side by side, electrical wiring connecting logically the same pins of the LSI package is arranged in the same layer of the package substrate without crossing. 9. The method according to claim 8, further comprising the step of forming a surface mounting package substrate having the provided structure. It resides in the way.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows an LSI package 2 for surface mounting according to a first embodiment of the present invention.
FIG. 4 is a bottom view of the package showing pin arrangements of the package substrate 7 for surface mounting and surface mounting. In FIG. 1, 11, 1
Reference numerals 2 and 20 denote LSI packages.

Referring to FIG. 1, an LSI of the present embodiment
The package 20 is the LSI package 11 (2
0) and two LSI packages 20 which are logically the same as the LSI package 12 (20) are characterized in that they have pin arrangements (1),. First feature point).

FIG. 2 shows an LSI package 20 of the same logic.
From two types of LSI packages 8 (20) and 9
It is the figure which showed the process of making (20). In FIG.
Reference numerals 3 and 4 denote outer leads, and reference numerals 8 and 9 denote LSI packages.

As shown in FIG. 2, the LSI package 20 according to the present embodiment has an LSI package having outer leads.
For the I package 20, by bending the outer leads 3 and 4 upward and downward, the LSI package 8 (20) and the LSI package 9 (20) are pin-symmetrical to each other (1),. ) Also has a feature (second feature point). For example, as shown in FIG.
By bending the outer leads 3 and 4 of the LSI package 8 (20) downward and bending the outer leads 3 and 4 of the LSI package 9 (20) upward, the LSI package 8 (20) and the LSI package 9 (20) are bent. ) Can have pin arrangements that are axisymmetric to each other.

As described above, the LSI package 20 is obtained by bending the pins (outer leads 3 and outer leads 4) downward as in the aforementioned LSI package 8 (20), or as in the LSI package 9 (20). The pins (outer leads 3 and outer leads 4) can be reshaped to be bent upward.

FIG. 3 is a side view showing a state where the LSI package 20 for surface mounting and the package substrate 7 for surface mounting according to the first embodiment of the present invention are mounted on both sides of the package substrate. is there. In FIG. 3, reference numeral 7 denotes a package substrate, 16 denotes a through hole, and L denotes an electric wiring length.

In this embodiment, as shown in FIG.
I package 8 (20) and LSI package 9 (20)
Are mounted at the same position on the front side (upper side) and the back side (lower side) of the package substrate 7. That is, the LS is placed immediately below the pins (outer leads 3 and outer leads 4) of the LSI package 8 (20) mounted on the front side (upper side).
The same pins (outer leads 3 and outer leads 4) of the I-package 9 (20) are arranged, and through-holes 16 are formed on the front side (upper side) and the back side (lower side) of the pad at the pin position of the package substrate 7. Can be connected. Thereby, the intersection of the electric wiring 5 and the electric wiring 6 (not shown) is eliminated, and the line length of the pins (outer leads 3 and outer leads 4) between the LSI package 8 (20) and the LSI package 9 (20) is reduced. There is an effect that the thickness can be reduced to near the thickness of the package substrate 7.

FIG. 4 is a top view of a substrate showing a state where the LSI package 20 for surface mounting and the package substrate 7 for surface mounting according to the first embodiment of the present invention are mounted on one surface of a package substrate. is there. In FIG. 4, 5, 6
Indicates electric wiring.

In the present embodiment, as shown in FIG. 4, the LSI package 8 (20) and the LSI package 8 (20) are mounted on one surface (the mounting surface of either the front surface or the rear surface) of the package substrate 7.
When the SI package 9 (20) is mounted, the intersection of the electric wiring (the electric wiring 5 and the electric wiring 6) is eliminated by facing the place where the electric wiring is to be shortened, and the wiring can be wired in the same layer of the package substrate 7. As a result, there is an effect that the wire length between the pins (outer leads 3 and outer leads 4) can be shortened.

As described above, according to the first embodiment, the following effects can be obtained. First, the first effect is
By making two types of the LSI package 20 for the front side (upper side) and the back side (lower side), the pin arrangements (1),... The wires (electric wires 5 and 6) can be connected by through holes 16 on the front side (upper side) and the back side (lower side), and can be shortened to the same length as the thickness of the package substrate 7. .

The second effect is that, by bending the outer leads upward or downward with respect to the LSI package 20 having the outer leads 3 and the outer leads 4, the LSI package 20 having the same logic has two types of LSIs. That is, the package 20 (8, 9) can be manufactured.

The third effect is that the length of the electric wiring L and the number of layers can be reduced by the structure of the LSI package 20 having the pin arrangements (1),.

(Second Embodiment) FIG. 5 shows an LSI package 2 for surface mounting according to a second embodiment of the present invention.
FIG. 2 is a perspective view of a substrate for explaining a package substrate 7 for surface mounting. In FIG. 5, 10 is a socket, 2
Reference numeral 1 denotes a QFP (Quad Flat Package).

In this embodiment, as shown in FIG.
The outer leads 3 and the outer leads 4 of the FP 21 are not bent and have no front side (upper side) and no back side (lower side).

As described above, by mounting the outer lead 3 and the outer lead 4 on the socket 10 without bending, the mounting can be performed on either the front side (upper side) or the back side (lower side).

In each of the above embodiments, two LSI packages 8 (20) and an LSI package 9 (2
If the pin arrangements (1),..., (20) of (0) are line-symmetric with respect to each other, the type of the LSI package 20 is not particularly relevant. Further, in the case of the LSI package 20 having the outer leads 3 and the outer leads 4, the outer package 3 and the outer leads 4 are bent so that the pin arrangement (1),. Is possible, but
As shown in FIG. 5, the outer lead 3 and the outer lead 4 may be mounted on the socket 10 without bending, so that the outer lead 3 and the outer lead 4 may be mounted on either the front side (upper side) or the back side (lower side). Further, the timing of bending the outer leads 3 and the outer leads 4 may be at the time of processing in the manufacturing process or immediately before mounting on the package substrate 7.

It should be noted that the present invention is not limited to the above embodiments, and it is clear that the embodiments can be appropriately modified within the scope of the technical idea of the present invention. Further, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to suitable numbers, positions, shapes, and the like for implementing the present invention. In each drawing, the same components are denoted by the same reference numerals.

[0032]

Since the present invention is configured as described above, the following effects can be obtained. First, the first effect is L
By making two types of SI packages, one for the front side and the other for the back side, the pin arrangement overlaps when both sides are mounted, and the electric wiring of the same signal can be connected by the through holes on the front side and the back side, and the package substrate That can be shortened to the same length as the thickness of

A second effect is that, by bending the outer leads upward or downward with respect to the LSI package having the outer leads, two types of LSI packages can be formed from the same logic LSI package. is there.

A third effect is that the length of the wiring and the number of layers can be reduced by the structure of the LSI package having the pin arrangement which is line-symmetric to each other.

[Brief description of the drawings]

FIG. 1 is a package bottom view showing a pin arrangement of an LSI package for surface mounting and a package substrate for surface mounting according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a process of producing two types of LSI packages from an LSI package of the same logic.

FIG. 3 is a substrate side view showing a state where the package is mounted on both sides of the package substrate using the surface mounting LSI package and the surface mounting package substrate according to the first embodiment of the present invention;

FIG. 4 is a substrate top view showing a state in which the LSI package for surface mounting and the package substrate for surface mounting according to the first embodiment of the present invention are mounted on one surface of a package substrate.

FIG. 5 is a perspective view of a substrate for explaining an LSI package for surface mounting and a package substrate for surface mounting according to a second embodiment of the present invention.

FIG. 6 is a connection diagram of a lead portion of a conventional LSI package and a package substrate.

FIG. 7 is a substrate side view showing a state in which a conventional LSI package is mounted on both sides of a package substrate.

FIG. 8 is a top view of a substrate showing a state in which a conventional LSI package is mounted on one surface of a package substrate.

[Explanation of symbols]

1, 2, 8, 9, 11, 12, 15, 20 ... LSI package 3, 4, 14 ... Outer lead 5, 6 ... Electric wiring 7 ... Package board 10 ... Socket 13 ... Solder part 16 ... Through hole 21 ... QFP L: Electrical wiring length

Claims (10)

[Claims] 1. An L for surface mounting having outer leads.
An LSI for surface mounting, comprising: an SI package, wherein all the outer leads are bent in one of an upper direction and a lower direction, and have the same function and only the pin arrangement is line-symmetric with each other. package. 2. A package board for surface mounting, which mounts an LSI package having the same function and only the pin arrangement is line-symmetrical to each other, wherein the LSI package is mounted on the front surface of the package substrate and directly below the rear surface thereof. Are mounted so as to be mirror-symmetrical to each other, and the length of the electrical wiring between the pads of the LSI package on the front surface side and the pads of the LSI package on the back side is reduced to near the thickness of the package substrate. A package substrate for surface mounting, having a structure connected by through holes as described above. 3. The surface mount type LSI package having a structure in which all outer leads are bent in one of an upper direction and a lower direction so that only the pin arrangement is line-symmetrical to each other with the same function. The package is mounted at a position directly below the front surface and the back surface thereof so as to be mirror-symmetrical with respect to the package substrate. The pads of the LSI package on the front surface and the LSI on the back surface are respectively mounted.
3. The package board for surface mounting according to claim 2, wherein the package board has a structure in which the electrical wiring length is connected to a pad of the package by a through hole so as to reduce an electric wiring length to a thickness close to the thickness of the package board. 4. When an LSI package having a pin arrangement for surface mounting on a package substrate and an LSI package having a pin arrangement for mounting on a back surface of the package substrate are mounted side by side on one surface of the package substrate, each of the LSI packages is Electrical wiring that connects logically the same pins,
A package substrate for surface mounting, having a structure arranged without crossing in the same layer of the package substrate. 5. An LSI having a pin arrangement for surface mounting of a package substrate, wherein all outer leads are bent in one of upper and lower directions and have the same function, and only the arrangement of the surface mounting pins is line-symmetric with each other. LS with pin arrangements for mounting the package and the backside of the package substrate, all outer leads are bent in either one of the upper and lower directions and have the same function and only the pin arrangements are line-symmetrical to each other
When the I package and the package are mounted side by side on one side of the package substrate, electrical wiring connecting logically the same pins of the LSI package is arranged in the same layer of the package substrate without crossing. The package substrate for surface mounting according to claim 4, comprising: 6. An L for surface mounting having outer leads.
All the outer leads of the SI package are bent upward or downward in one direction, and the same function is used.
A surface mounting method comprising a step of forming an SI package. 7. A surface mounting method for producing a surface mounting package substrate for mounting an LSI package having the same function and only the pin arrangement being line-symmetric with respect to each other, comprising: Mounted so as to be mirror-symmetrical to each other at a position immediately below the front surface and the back surface thereof, and set the electric wiring length between the pads of the LSI package on the front surface and the pads of the LSI package on the back surface in accordance with the package. A surface mounting method characterized by comprising a step of forming a surface mounting package substrate having a structure connected by through holes so as to be shortened to near the thickness of the substrate. 8. The surface mount type LSI package having a structure in which all outer leads are bent in one of upward and downward directions and only the pin arrangement is symmetrical to each other with the same function, The package is mounted at a position directly below the front surface and the back surface thereof so as to be mirror-symmetrical with respect to the package substrate, and the pads of the LSI package on the front surface and the LSI on the back surface are respectively mounted.
A step of forming a package board for surface mounting having a structure in which through-holes are connected between the pads of the package and the electric wiring length to be close to the thickness of the package board. The surface mounting method according to claim 7. 9. When mounting an LSI package having a pin arrangement for surface mounting on a package substrate and an LSI package having a pin arrangement for mounting on a back surface of the package substrate side by side on one surface of the package substrate, the respective packages of the LSI package are provided. Electrical wiring that connects logically the same pins,
A surface mounting method characterized by comprising a step of forming a surface mounting package substrate having a structure arranged without crossing in the same layer of the package substrate. 10. An LSI having a surface mounting pin arrangement on a package substrate, wherein all outer leads are bent in either one of the upper and lower directions and have the same function and only the surface mounting pin arrangement is line-symmetric with each other. The package has a pin arrangement for mounting on the back surface of the package and the package substrate, and all the outer leads are bent in one of the upper and lower directions, and only the pin arrangement is line-symmetric with each other with the same function.
When the SI package and the package are mounted side by side on one side of the package substrate, electrical wiring for connecting logically the same pins of the LSI package is arranged in the same layer of the package substrate without crossing. 9. The surface mounting method according to claim 8, further comprising a step of forming a surface mounting package substrate provided with: