JPH09306942A - Mounting structure of bare chip having electrodes at both sides and mounting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure of bare chip having electrodes at both sides and mounting the same which enables the bare chip to be cooled at the lower and upper sides and to be mounted by the simple SMT or FC method only. SOLUTION: The mounting structure comprises a bare chip 3 having electrodes at both sides to be fixed to a substrate 1, a metal frame 7 integrated with an insulation member having a thermal conductivity, and a radiating member mounted on the insulation member. The lower electrode 4a of the chip 3 is connected to a first electrode 2a of the substrate 1, one end of the frame is connected to the upper electrode of the chip 3, and the other end of the frame 7 is connected to a second electrode 2b of the substrate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bare chip mounting structure having double-sided electrodes and a mounting method thereof.

[0002]

2. Description of the Related Art Bare chips having conventional double-sided electrodes are
SMT (Surface Mount Technology)
gy) method or flip chip (FC) method, after mounting the electrodes under the bare chip on the substrate, wire bonding (WB) method or TAB (Tap) method.
By using the e Automated Bonding method, the electrodes on the upper part of the bare chip are connected to the substrate, and finally, the area around the bare chip is hardened with resin to protect the upper electrode itself from disturbance (for example, rust) or to prevent the electrical connection between the upper electrode and the substrate. Connection is ensured (JP-A-5-10239).
No. 0, JP-A-5-144985, etc.).

[0003]

However, the above-mentioned conventional bare chip mounting method having a double-sided electrode requires protection of the electrode itself on the bare chip and secures electrical connection between the electrode on the bare chip and the substrate. Since the area around the bare chip is covered with resin for the purpose, if the resin has a certain amount of thickness, for example, if the bare chip is one with a large amount of heat generation such as a power transistor, the heat should be released only from the bottom of the bare chip. However, the heat dissipation effect was not sufficiently obtained.

Further, the connection between the electrode on the bare chip and the substrate is made by W. Since the B method or the TAB method is used,
This requires specialized equipment and technology, which not only increases man-hours but also increases costs. The present invention solves the above problems, and not only in the bare chip lower part,
It is an object of the present invention to provide a bare chip mounting structure having double-sided electrodes and a mounting method thereof, which is aimed at a cooling effect from the upper part and can be mounted only by a simple SMT method or FC method.

[0005]

In order to achieve the above object, the present invention provides a bare chip having a double-sided electrode fixed to the substrate in a mounting structure of a bare chip having a double-sided electrode on a substrate, A conductive frame integrally molded with an insulating member having thermal conductivity; and a heat dissipation member mounted on the insulating member, the lower electrode of the bare chip and the first of the substrate.
Of the conductive frame, one end of the conductive frame is connected to the upper electrode of the bare chip, and the other end of the conductive frame is connected to the second electrode of the substrate.

[2] In the bare chip mounting structure having the double-sided electrode according to the above [1], the heat dissipating member has a recess corresponding to the conductive frame. [3] In the bare chip mounting structure having the double-sided electrode according to the above [1], the heat dissipation member is made of solder-plated copper. [4] In the bare chip mounting structure having the double-sided electrode according to the above [1], the conductive frame is made of aluminum.

[5] In a method of mounting a bare chip having a double-sided electrode on a substrate, a step of connecting a lower electrode of the bare chip having a double-sided electrode to a first electrode of the substrate, and radiating heat to the upper electrode of the bare chip. A step of connecting one end of a conductive frame integrally molded with a heat-conducting insulating member for mounting the member and connecting the other end of the conductive frame to the second electrode of the substrate. is there.

[6] In the bare chip mounting method having the double-sided electrode according to the above [5], the heat dissipation member has a recess corresponding to the conductive frame to increase a heat dissipation area.

[0009]

According to the present invention, the following operational effects can be obtained. (A) Since the lower electrode of the bare chip having double-sided electrodes is mounted on the first electrode of the substrate, heat can be radiated from the lower portion of the bare chip. In addition, one end of a conductive frame integrally formed with an insulating member having thermal conductivity is connected to the upper electrode of the bare chip, the other end is connected to the second electrode of the substrate, and a heat dissipation member is provided on the insulating member. Since it was mounted, unlike the conventional technology in which the periphery of the bare chip was covered with resin, heat does not fully transfer through the thick resin, and it is possible to avoid contact between conductive frames. Since heat is transferred to the heat dissipation member through the thick insulating member, it is possible to dissipate heat from the upper part of the bare chip, and the performance and function of the chip itself are surely guaranteed.

Further, the upper electrode of the bare chip is connected to one end of a conductive frame integrally molded with an insulating member having thermal conductivity, and the other end is connected to the second electrode of the substrate. W. requiring specialized equipment and technology It is not necessary to use B method or TAB method, and SMT
Mounting can be performed only by the construction method or the FC construction method, and bare chip mounting having double-sided electrodes can be performed by a simple method.

Further, since the upper electrode of the bare chip is connected to one end of a conductive frame integrally formed with an insulating member having thermal conductivity and the other end is connected to the second electrode of the substrate, the conductive frame is formed. It is possible to prevent mutual contact, and ensure electrical connection. (B) Since the insulating member and the heat dissipating member have the recesses corresponding to the conductive frame, the insulating member and the heat dissipating member serve as a heat dissipating fin, and a further cooling effect can be achieved.

Further, since the insulating member and the heat dissipating member have the recesses corresponding to the conductive frame, it becomes possible to visually confirm the connection portion between the upper electrode of the bare chip and the conductive frame after mounting the respective members, and the bare chip can be visually confirmed. The electrical connection between the board and the board is secured.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings. 1 is a perspective view showing a state in which a bare chip having double-sided electrodes is mounted on a substrate showing an embodiment of the present invention, FIG. 2 is a side view of the bare chip having the double-sided electrodes, and FIG. 3A is a vertical cross-sectional view of the conductive frame with the radiation fins, FIG. 3B is a top view of the first layer of the conductive frame with the radiation fins, and FIG. 3C. Is a top view of the second layer of the conductive frame with the radiation fins, FIG.
FIG. 3D is a top view of the third layer of the conductive frame with the radiation fins, and FIG. 3E is a top view of the fourth layer of the conductive frame with the radiation fins.

In these figures, 1 is a substrate, 2a is a first electrode to which the lower surface of a bare chip is connected, 2b is a second electrode formed on the substrate, and 3 is a double-sided electrode mounted on the substrate. A bare chip having 4a, a lower electrode formed on the lower surface of the bare chip, 4b an upper electrode formed on the bare chip 3, 5 a conductive frame with a radiation fin mounted on the bare chip 3, and 6 an insulating Highly heat conductive resin (for example, Toray SE4400), 7 is a metal frame, and 8 is a radiation fin.

The conductive frame 5 with the radiation fins is shown in FIG.
It has a vertical sectional structure as shown in FIG. That is, the metal frame 7 is provided integrally with the insulating high thermal conductive resin 6, and the heat radiation fins 8 are mounted on the insulating high thermal conductive resin 6. When viewed from the side, the metal frame 7 is connected to the upper electrode 4b of the bare chip 3 having a double-sided electrode at the tip, and a connection pad portion 7a that is connected to the connection pad portion 7a and is offset upward to form an insulating high thermal conductive resin. 6 and the conductor portion 7b integrated in the
It has a lead-out electrode portion 7c that is connected to b and is led out to the outside, and is connected to the second electrode 2b of the substrate at the tip. Note that 6
Reference symbol a is a recess formed in the insulating high thermal conductive resin 6, and reference symbol 8a is a recess formed in the radiation fin 8.

The method for mounting a bare chip having double-sided electrodes according to the present invention will be described below with reference to FIG.
FIG. 4 is a sectional view of a bare chip having a double-sided electrode according to the present invention in a mounting step, and FIG. (1) First, as shown in FIG. 4A, the bare chip 3 having double-sided electrodes is positioned on the first electrode 2a to which the lower surface of the bare chip 3 on the substrate 1 is connected. In addition, 1
Reference numeral 1 denotes a vacuum nozzle, and the vacuum nozzle 11 sucks the upper surface of the bare chip 3 to convey and position it.

(2) Next, as shown in FIG. 4B, the vacuum nozzle 11 is lowered to mount the lower electrode 4a of the bare chip 3 on the first electrode 2a on the substrate 1. (3) Next, as shown in FIG. 4C, the conductive frame 5 with the radiation fins is transported by the vacuum nozzle 11 so as to be positioned on the bare chip 3 on the mounted substrate 1. This step is shown as a perspective view in FIG. That is, the connection pad portion 7a of the metal frame 7 of the conductive frame 5 with the heat radiation fin is attached to the upper electrode 4b on the bare chip 3 mounted on the substrate 1, and the second electrode 2b formed on the substrate 1 is provided with the heat radiation fin. The lead-out electrode portions 7c of the metal frame 7 of the conductive frame 5 are positioned so as to coincide with each other.

(4) Next, as shown in FIG.
The vacuum nozzle 11 descends, and the connection pad portion 7a of the metal frame 7 becomes the upper electrode 4b formed on the bare chip 3.
In addition, the lead-out electrode portion 7c of the metal frame 7 of the conductive frame 5 with the radiation fins is formed on the substrate 1 by the second electrode 2
It is mounted by abutting on each of b. With the above configuration, according to the present invention, (A) the lower electrode 4a of the bare chip 3 having double-sided electrodes is connected to the first electrode 2a of the substrate 1. Dissipates heat.

Further, the upper electrode 4b of the bare chip 3 is connected to the connection pad portion 7a at one end of the metal frame 7 integrally molded with the insulating high thermal conductive resin 6, and the lead electrode portion 7c at the other end of the metal frame 7 is connected. It is connected to the second electrode 2b of the substrate 1, and the heat radiation fin 8 is provided on the insulating high thermal conductive resin 6.
Since it was mounted, unlike the conventional technology in which the surroundings of the bare chip were covered with resin, heat does not fully transfer through the thick resin, and it is possible to avoid contact between metal frames. Since the heat is transmitted to the heat radiation fins 8 through the insulating high thermal conductive resin 6 having the thickness of, the heat radiation from the upper portion of the bare chip 3 is also possible, and the performance and function of the chip itself are surely guaranteed.

The upper electrode 4b of the bare chip 3 is connected to the connection pad portion 7a at one end of the metal frame 7 integrally molded with the insulating high thermal conductive resin 6, and the lead electrode 7c at the other end of the metal frame 7 is connected to the substrate. Since it is connected to the second electrode 2b of No. 1, the W. It is not necessary to use the B method or the TAB method, the mounting can be performed only by the SMT method or the FC method, and bare chip mounting having double-sided electrodes can be performed by a simple method.

Further, on the upper electrode 4b of the bare chip 3,
The connection pad portion 7a at one end of the metal frame 7 integrally molded with the insulating high thermal conductive resin 6 having heat conductivity is connected, and the lead electrode portion 7c at the other end of the metal frame 7 is connected to the second electrode 2b of the substrate 1. Since the metal frames are connected to each other, it is possible to prevent the metal frames from contacting each other and ensure the electrical connection.

(B) Since the insulating high thermal conductive resin 6 and the heat radiating fin 8 have the recesses 6a, 8a corresponding to the metal frame 7, the insulating high thermal conductive resin 6 and the radiating fin 8 can enhance the heat radiating effect. . In addition, the insulating high thermal conductive resin 6 and the heat radiation fins 8 are formed in the concave portion 6 corresponding to the metal frame 7.
Since it has a and 8a, it becomes possible to visually confirm the connection portion between the upper electrode 4b of the bare chip 3 and the metal frame 7 after mounting the respective members, and ensure the electrical connection between the bare chip 3 and the substrate 1. Become.

The conductive frame described above is made of solder-plated copper, and can be easily mounted and fixed by solder reflow. Further, the above-mentioned heat dissipation member can be made of aluminum which is inexpensive and lightweight. It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a bare chip having double-sided electrodes is mounted on a substrate showing an embodiment of the present invention.

FIG. 2 is an enlarged side view of a bare chip having double-sided electrodes according to an embodiment of the present invention.

FIG. 3 is a diagram showing a structure of a conductive frame with a radiation fin showing an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a bare chip mounting process having double-sided electrodes according to the present invention.

FIG. 5 is a perspective view showing a part of a mounting process of a bare chip having a double-sided electrode of the present invention.

[Explanation of symbols]

 1 Substrate 2a First Electrode 2b Second Electrode 3 Bare Chip 4a Lower Electrode 4b Upper Electrode 5 Conductive Frame with Radiating Fin 6 Insulating High Thermal Conductive Resin 6a, 8a Recess 7 Metal Frame 7a Connection Pad 7b Conductor 7c Derived Electrode 8 Radiating fin 11 Vacuum nozzle

Claims (6)

[Claims] 1. In a mounting structure of a bare chip having a double-sided electrode on a substrate, (a) a bare chip having a double-sided electrode fixed to the substrate and (b) a conductive member integrally molded with an insulating member having thermal conductivity. A frame; and (c) a heat dissipation member mounted on the insulating member, (d) the lower electrode of the bare chip and the first electrode of the substrate are connected, and one end of the conductive frame is A mounting structure of a bare chip having a double-sided electrode, which is connected to an upper electrode of the bare chip and the other end of the conductive frame is connected to a second electrode of the substrate. 2. The bare chip mounting structure having a double-sided electrode according to claim 1, wherein the heat dissipation member has a recess corresponding to the conductive frame. 3. The bare chip mounting structure having a double-sided electrode according to claim 1, wherein the conductive frame is made of solder-plated copper. 4. The bare chip mounting structure having a double-sided electrode according to claim 1, wherein the heat dissipation member is made of aluminum. 5. A method of mounting a bare chip having a double-sided electrode on a substrate, comprising: (a) connecting a lower electrode of the bare chip having a double-sided electrode to a first electrode of the substrate;
(B) One end of a conductive frame integrally formed with an insulating member having a heat conductivity for mounting a heat dissipation member thereon is connected to the upper electrode of the bare chip, and the other end of the conductive frame is connected to the second electrode of the substrate. A method of mounting a bare chip having a double-sided electrode, which comprises performing a step of connecting to an electrode. 6. The bare chip having a double-sided electrode according to claim 5, wherein the heat-dissipating member has a recess corresponding to the conductive frame to increase a heat-dissipating area. How to implement.