JPH0936514A - Printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin printed board and a miniaturized IC chip by a method wherein the bonding of the IC chip, which is buried in a board, is conducted in the internal part of the printed board using a conductive wiring provided in the printed board. SOLUTION: A PWB 1 is composed of the glass epoxy resin such as BT resin etc., for example, or ceramic material, and a hole part 1A is formed. A conductive wiring 2 is provided in the internal part of the PWB 1 and it is extended in parallel with the surface of a board. An IC chip 3 is inserted into the hole part 1A of the PWB 1 which is formed in such a manner that it is coincided with the external dimensions of the IC chip 3. The outer surface of a die pad 4 is exposed to the board surface of the PWB 1, the die pad 4 functions as a heat spreader, and it performs a heat discharging action which discharges the heat of the IC chip 3 to outside the PWB 1. By protruding the end part of the conductive part 2, it can be bonded to the IC chip 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board (hereinafter referred to as PW) in which a semiconductor element including an IC chip is mounted on a printed circuit board (hereinafter referred to as PWB).
(Abbreviated as CB).

[0002]

2. Description of the Related Art FIGS. 5 and 6 show conventional examples. In FIG. 5, the conventional PCB mounted with an IC chip has mounted the IC chip 3 on the land on the PWB 1 and soldering the external lead L of the IC 3.

Further, as shown in FIG. 6, a recent MCM
In the (multi-chip module), the IC chip main body 3 is placed on the PWB 1, the wiring W is performed, and the mold coating is performed to produce the IC mounted product.

FIG. 7 shows a ball grid array (referred to as BGA). In FIG. 7, 1 is PWB,
2 is a conductive wiring provided inside the PWB 1 and 3 is P
IC chip inserted in hole 1A made in WB1, 9
Is a through hole and 10 is a solder ball. The conductive wiring 2 and the IC chip 3 are wired W.

The problems of these conventional examples are as follows. (1) Substrate thickness + IC chip thickness + Wire bond height +
Since the thickness corresponding to the mold thickness is required, the total product thickness becomes large, creating the limit of compact products. (2) A space within the range around the IC chip is required for wire bonding. Otherwise, the edge of the IC chip and the wire will be short-circuited. (3) There is a limit to the bond diameter for the convenience of wire bonding work, and there is a limit to the fine pitch of the conductive wiring of the PWB and the fine pitch of the IC chip. (4) A high power IC chip cannot be mounted. Poor heat dissipation. It should be noted that the conventional technology, PPGA / CPG
A / BGA also has the same problem because it has a wiring structure.

[0006]

A first aspect of the present invention is intended to reduce the thickness of a printed circuit board in a state in which the IC chip is mounted by bonding the IC chip to the inside of the printed circuit board by means of the conductive wiring, thereby achieving a fine pitch of the conductive wiring. The miniaturization of the IC chip is aimed at by this.

A second aspect of the invention is to further reduce the thickness of the printed circuit board and to reduce the size of the IC chip.

A third aspect of the invention is to further reduce the thickness of the printed circuit board and reduce the size of the IC chip.

A fourth aspect of the invention is to further reduce the thickness of the printed circuit board and to reduce the size of the IC chip.

A fifth aspect of the invention is to further reduce the thickness of the printed circuit board and reduce the size of the IC chip.

A sixth aspect of the present invention is intended to improve heat dissipation of a thin printed circuit board.

A seventh aspect of the invention is to realize a structure of a ball grid array in a thin printed board.

[0013]

Means for Solving the Problems In the first invention,
Bonding with an IC chip embedded in the board is performed inside the printed board by conductive wiring provided inside the printed board.

According to a second aspect of the present invention, there is provided an IC chip embedded inside the substrate, and a conductive wiring provided inside the printed circuit board and extending parallel to the surface of the printed circuit board. It is the one that binds internally.

According to a third aspect of the present invention, there is provided an IC chip fitted in a hole provided in the printed board, and a conductive wiring provided inside the printed board and having an end extending into the hole. In the section, the IC chip and the conductive wiring are coupled.

According to a fourth aspect of the invention, a resin coat is provided at the connecting portion between the IC chip and the conductive wiring to cover this portion.

According to the fifth aspect of the invention, a lid is provided at the connecting portion between the IC chip and the conductive wiring to cover this portion.

In the sixth invention, a heat spreader is provided, one surface of which is in contact with the IC chip and the other surface of which is exposed on the surface of the printed circuit board.

According to a seventh aspect of the invention, a ball grid array is constructed by including solder balls connected to through holes provided on the printed board.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. FIG. 1 is a sectional view showing an embodiment of an IC chip surface resin coat type. In FIG. 1, 1
Is PWB, 2 is a conductive wiring provided inside the PWB 1, and 3 is an IC inserted in a hole 1A formed in the PWB 1.
Chips, 4 are heat spreaders consisting of die pads, 5
Is a resin-attached portion of the die pad 4, and 6 is a resin coat.
The PWB 1 is made of, for example, a glass epoxy resin such as BT resin or a ceramic material, and forms the hole 1A. Conductive wiring 2 is provided inside PWB 1 and extends parallel to the substrate surface. The IC chip 3 is fitted into the hole portion 1A of the PWB 1 formed so as to match its outer dimensions. The die pad 4 has a PW outer surface.
It is exposed to the substrate surface of B1 and has a function as a heat spreader, and performs a heat radiation function of releasing the heat generated in the IC chip 3 to the outside of the PWB1. The end of the conductive wiring 2 is
By protruding like a lead into the hole 1A, the P
It becomes possible to bond with the IC chip 3 fitted in the hole 1A made in WB1, and an electrical connection is obtained. As a result, the IC chip 3 is built in the substrate thickness of the PWB 1 in the PCB, which enables thinning and high mounting.

An example of the manufacturing flow in the first embodiment will be described below with reference to FIG. (A) A hole 1A having the same size as the IC chip 3 is formed in the substrate core of the PWB 1. (B) A rolled conductive material is placed. (C) A wiring circuit mask for forming the conductive wiring 2 is placed, photolithography is performed, and etching is performed. (D) Two or more conductive wires 2 are alternately stacked on the substrate layer of the PWB 1 according to the wiring density. (E) These are pressed and bonded. (F) With the IC chip 3 die-bonded onto the heat spreader 4, the heat spreader 4 and the PWB 1 substrate are resin-bonded by inserting the heat spreader 4 and the PWB 1 substrate from the bottom of the PWB 1 into the hole 1A formed in the substrate. (G) Conductive wiring (lead shape) 2 protruding from the upper part of the substrate
And the bumps on the IC chip 3 are applied with heat or mechanically bonded. (H) Finally, resin sealing is performed to form the resin coat 6.

Embodiment 2 FIG. FIG. 2 shows the first embodiment.
FIG. 6 is a cross-sectional view showing an embodiment of a lid attachment type which is an airtight type of FIG. In FIG. 2, 1 is a PWB, 2 is a conductive wire provided inside the PWB 1, 3 is an IC chip inserted in a hole 1A made in the PWB 1, 4 is a heat spreader made of a die pad, and 5 is a resin of the die pad 4. The above structure is the same as that of the first embodiment. Reference numeral 7 is a lid, and 8 is a resin-attached portion of the lid 7. The configuration of this portion is different from that of the first embodiment. The lid 7 is fitted into the PWB 1 at the upper part of the IC chip 3 and is sealed by the resin attachment part 8.

An example of the manufacturing flow in the second embodiment will be described below with reference to FIG. (A) A hole 1A having the same size as the IC chip 3 is formed in the substrate core of the PWB 1. (B) A rolled conductive material is placed. (C) A wiring circuit mask for forming the conductive wiring 2 is placed, photolithography is performed, and etching is performed. (D) Two or more conductive wires 2 are alternately stacked on the substrate layer of the PWB 1 according to the wiring density. (E) These are pressed and bonded. (F) With the IC chip 3 die-bonded onto the heat spreader 4, the heat spreader 4 and the PWB 1 substrate are resin-bonded by inserting the heat spreader 4 and the PWB 1 substrate from the bottom of the PWB 1 into the hole 1A formed in the substrate. (G) Conductive wiring (lead shape) 2 protruding from the upper part of the substrate
And the bumps on the IC chip 3 are applied with heat or mechanically bonded. (H) The lid 7 is fitted into the PWB 1 and is resin-attached by the resin attachment portion 8 to perform lid attachment and sealing.

Embodiment 3. FIG. 3 shows the present invention as a BGA.
It is sectional drawing which shows embodiment applied to. In FIG. 3, 1 is a PWB, 2 is conductive wiring provided inside the PWB 1, 3 is an IC chip inserted in a hole 1A made in the PWB 1, 4 is a heat spreader made of a die pad, and 5 is a die pad 4. The resin-attached portion 6 is a resin coat, and the above configuration is the same as that of the first embodiment. Reference numeral 9 is a through hole, and 10 is a solder ball, which constitutes a central portion that exerts the function of the BGA, and this portion is characteristic of the third embodiment. The portion of the solder ball 10 connected to the through hole 9 serves as a lead for external connection.

[0025]

According to the first aspect of the present invention, by bonding the IC chip to the inside of the printed circuit board by the conductive wiring, the printed circuit board can be thinned in the IC chip mounted state, and the conductive wiring can have a fine pitch. It is possible to reduce the size of the IC chip.

According to the second invention, it is possible to further reduce the thickness of the printed circuit board and to reduce the size of the IC chip.

According to the third invention, it is possible to further reduce the thickness of the printed circuit board and reduce the size of the IC chip.

According to the fourth aspect of the present invention, the printed circuit board can be made even thinner and the IC chip can be made smaller.

According to the fifth aspect of the invention, the printed circuit board can be made even thinner and the IC chip can be made smaller.

According to the sixth aspect of the invention, it is possible to improve the heat dissipation of the thin printed circuit board.

According to the seventh invention, the structure of the ball grid array can be realized in the thin printed board.

[Brief description of drawings]

FIG. 1 is a sectional view of a resin coat type PCB according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a lid-type PCB according to Embodiment 2 of the present invention.

FIG. 3 is a sectional view of a PCB according to a third embodiment of the present invention.

FIG. 4 is a first embodiment and a second embodiment of the present invention.
It is a figure which shows the example of a manufacturing flow.

FIG. 5 is a sectional view of a PCB product on which a conventional plastic mold IC is mounted.

FIG. 6 is a cross-sectional view of a product in which an IC chip is placed on a conventional PCB, wire-bonded, and potting-coated with a resin.

FIG. 7 is a sectional view of a conventional BGA.

[Explanation of symbols]

1 PWB, 2 conductive wiring, 3 IC chip, 4 die pad having a function as a heat spreader, 5 resin pad of die pad 4, 6 resin coat, 7 lid, 8
Resin part of lid 7, 9 through holes, 10 solder balls.

Claims (7)

[Claims] 1. A printed circuit board, wherein bonding with an IC chip embedded in the printed circuit board is performed in the printed circuit board by conductive wiring provided in the printed circuit board. 2. An IC chip embedded inside a substrate, and a conductive wiring provided inside the printed circuit board and extending parallel to the surface of the substrate, wherein the IC chip and the conductive wiring are coupled inside the printed circuit board. A printed circuit board featuring. 3. An IC chip fitted into a hole provided in a printed circuit board, and a conductive wiring provided inside the printed circuit board and having an end extending into the hole, wherein the IC chip is provided in the hole. A printed circuit board, characterized in that the printed circuit board and the conductive wiring are connected. 4. The connecting portion between the IC chip and the conductive wiring,
The printed circuit board according to claim 1, further comprising a resin coat that covers this portion. 5. The connecting portion between the IC chip and the conductive wiring,
4. The printed circuit board according to claim 1, further comprising a lid that covers this portion. 6. The printed circuit board according to claim 1, further comprising a heat spreader having one surface in contact with the IC chip and the other surface exposed to the printed circuit board surface. 7. The ball grid array according to claim 1, further comprising a solder ball connected to a through hole provided on the printed board.
Printed circuit board according to any one of.