JPH02163950A - Mounting of semiconductor device - Google Patents

Abstract

PURPOSE:To electrically connect a semiconductor device to a circuit board with good reliability by a method wherein a convex bump electrode composed of a two-step shape of a pedestal part and a top part is installed on an electrode pad part of the semiconductor device and the bump electrode is connected electrically to a terminal electrode part on the circuit board via a conductive adhesive having flexibility. CONSTITUTION:When a semiconductor device 1 is mounted on a terminal electrode part 5 on a circuit board 6, a convex bump electrode 3 composed of a two-step shape of a pedestal part and a top part is formed on an electrode pad part 2 of the semiconductor device 1; the bump electrode 3 is connected electrically to the terminal electrode part 5 on the circuit board 6 via a conductive adhesive 4 having flexibility. For example, a two-step-shaped and projected bump electrode 3 is formed in advance on an electrode pad part 2 of a semiconductor device 1 ; a conductive adhesive 4 having flexibility is formed on the bump electrode 3 by a transcription operation or a printing operation. After that, the semiconductor device 1 is aligned with a terminal electrode part 5 of a circuit board 6 in a face-down manner, the semiconductor device 1 is mounted on the circuit board 6; after that, the conductive adhesive 4 is hardened by heating.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrical connection between a semiconductor device and a terminal electrode portion on a circuit board, and in particular to a face-down bonding method using a conductive adhesive. The present invention relates to a method for mounting such a semiconductor device.

Conventional technology In the past, soldering was often used to connect the connection terminals of electronic components and the circuit pattern terminals on the circuit board, but in recent years, soldering has become more popular due to the miniaturization of IC flat packages and the increase in the number of connection terminals. As the so-called pitch distance between connecting terminals becomes narrower and narrower, conventional soldering technology becomes increasingly difficult to overcome.

Therefore, recently, a method has been developed in which a bare semiconductor device is directly attached to a terminal electrode portion on a circuit board in order to efficiently use the mounting area.

Among these, when connecting semiconductor devices to circuit boards,
With the semiconductor device facing downward, a three-layer metal vapor deposition film of Cr, Cu, and AU is formed on the electrode pad of the semiconductor device in advance, and then a resist is applied and solder is formed on the metal vapor deposition film by plating or vapor deposition. However, the method of heating and fusing solder bump electrodes formed by removing excess resist and metal vapor deposition film at high temperatures is an effective method because the mechanical strength after connection is strong and connections can be made all at once. It is said that there is. (Industrial Research Group, January 15, 1980, published by Japan Microelectronics Association, RLC Mounting Technology) An example of the above-mentioned conventional method for mounting a semiconductor device using solder bumps will be described below with reference to the drawings.

FIG. 3 is a schematic explanatory diagram of a conventional method for mounting a semiconductor device using solder bumps. In FIG. 3, 7 is a semiconductor device, and 8 is a solder bump electrode. 9 is a terminal electrode portion, and 10 is a circuit board.

A method for mounting a semiconductor device using solder bumps configured as described above will be briefly described below.

First, solder bump electrodes 8 are formed in advance on the electrode pads made of AI of the semiconductor device 7 by plating or the like, and the semiconductor device 7 is aligned face-down with the terminal electrodes 9 of the circuit board 10. , 200~300°
The semiconductor device is mounted by heating to a high temperature of C to melt the solder bump electrodes 8 and fusing them to the terminal electrode portions 9 of the circuit board 10.

Problems to be Solved by the Invention However, in the method of mounting a semiconductor device using solder bump electrodes as described above, (1) it is necessary to heat the solder to a high temperature when melting it, and it is easily affected by thermal stress.

(2) Since the connection is made by soldering, the terminal electrode portion on the circuit board side must be able to be connected by soldering, which lacks versatility.

(3) When the solder forming the solder bump electrode is heated and melted, it spreads and there is a risk of short-circuiting with the adjacent electrode.

(4) Since Si having different coefficients of thermal expansion and the circuit board are connected only by hard solder, it is extremely brittle against thermal stress.

There were issues such as:

The present invention has been made in view of the above problems, and its purpose is to provide a method for mounting a semiconductor device that can electrically connect a semiconductor device and a circuit board with high reliability. It is.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a method for mounting a semiconductor device onto a terminal electrode portion on a circuit board. A highly reliable semiconductor, characterized in that it has a convex bump electrode, and the bump electrode is electrically connected to a terminal electrode portion on a circuit board via a flexible conductive adhesive. The purpose is to realize electrical connection of devices.

Operation The present invention connects a two-step convex bump electrode formed in advance on an electrode pad portion of a semiconductor device to a terminal electrode on a circuit board via a flexible conductive adhesive by the method described above. As a result, it is possible to realize highly reliable electrical connections of semiconductor devices that are stable against stress and free from short-circuits to adjacent devices even in connection with a minute pitch.

EXAMPLE Hereinafter, a method for mounting a semiconductor device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged view of a connection portion according to a method for mounting a semiconductor device according to an embodiment of the present invention, and FIG. 2 is a schematic explanatory diagram of a method for mounting a semiconductor device according to an embodiment of the present invention.

In FIG. 1 and FIG. 2, 1 is a semiconductor device,
2 is an electrode pad section. 3 is a two-stage convex bump electrode, and 4 is a flexible conductive adhesive.

5 is a terminal electrode portion, and 6 is a circuit board.

A method for mounting a semiconductor device configured as described above will be described below with reference to the drawings.

First, place two pads on the electrode pad portion 2 of the semiconductor device 1 in advance.
A stepped and convex bump electrode 3 is formed in advance, and a flexible conductive adhesive 4 is formed on the bump bridge 3 by transfer or printing.

After that, this semiconductor device 1 is aligned face-down with the terminal electrode part 5 of the circuit board 6, and after mounting the semiconductor device 1 on the circuit board 6, the conductive adhesive 4 is cured by heating. As shown in FIGS. 1 and 2, a semiconductor device 1 has a two-stage convex bump electrode 3.
And it is electrically connected to the terminal electrode 5 of the circuit board 6 via the flexible conductive adhesive 4 .

At this time, since the conductive adhesive 4 is flexible, there is a difference in thermal expansion coefficient between the Si substrate that constitutes the semiconductor device 1 and the alumina substrate or glass substrate that constitutes the circuit board 6. Thermal stress caused by this can be alleviated, improving the stability of the connection.

In addition, since the heating for curing the conductive adhesive 4 can be performed at a lower temperature than the conventional connection using solder bumps, the influence of thermal stress during thermosetting can be reduced, and the adhesive can be easily and stably bonded. You get a connection.

Furthermore, since the bump electrodes 3 are convex and have a two-stage shape with a pedestal and a top, it is possible to restrict the spread of the conductive adhesive 4 when the semiconductor device 1 is connected to the circuit board 6, and it is possible to control the spread of the conductive adhesive 4 at a fine pitch. Highly reliable connections with no short circuits can be achieved in connection as well.

Moreover, since the electrical connection between the bump electrode 3 and the terminal electrode section 5 of the circuit board 6 is made by adhesion using the conductive adhesive 4, the material of the terminal electrode section 5 of the circuit board 6 may be any wiring material. , versatile.

As described above, it becomes possible to mount the semiconductor device 1 on the circuit board 6 extremely stably, with good reliability, and with high density.

In this embodiment, the two-stage convex bump electrode 3 is made of Au, but its material is not limited to Au. For example, it may be made of other metals such as Cu. good.

Further, the formation of the bump electrode 3 is not limited to the conventional method of forming by plating, but may be formed by any method. Anything is fine.

Further, the conductive adhesive 4 may be made of any material as long as it has flexibility. For example, it may be a flexible conductive adhesive such as silicone, or may be made of epoxy, polyimide, etc. It is also possible to use a conductive adhesive such as acrylic or phenolic adhesive with flexibility.

In addition, in this embodiment, the conductive adhesive 4 is applied to the bump electrode 3.
Although the conductive adhesive 4 is formed on the terminal electrode portion 5 side of the substrate 6, the conductive adhesive 4 may be formed on the terminal electrode portion 5 side of the substrate 6 using a printing or transfer method.

Furthermore, the conductive filler dispersed in the conductive adhesive 4 includes
Powders of metals or alloys such as Ag, Au5PdSN i, and C can be used alone or in combination, and the particle size and shape are not particularly limited.

Effects of the Invention As explained above, according to the method for mounting a semiconductor device of the present invention, two stages of a pedestal part and a top part are formed on an electrode band part of a semiconductor device using a flexible conductive adhesive. Since the electrical connection is made by adhesion between the convex bump electrode and the terminal electrode on the circuit board, it is possible to realize an extremely stable electrical connection against stress, and it is possible to connect at a fine pitch. It is also of extremely high practical value because it can realize highly reliable connections without short circuits with adjacent connections.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of a connection part according to a method for mounting a semiconductor device in an embodiment of the present invention, and FIG. 2 is a front view for explaining the outline of a method for mounting a semiconductor device in an embodiment of the present invention. FIG. 3 is a front view for explaining the outline of a conventional method for mounting a semiconductor device using solder bumps. 1.7... Semiconductor device, 2... Electrode pad portion, 3... Two-stage convex bump electrode,
4... Flexible conductive adhesive, 5.9.
...Terminal 1 is the bridge part, 6.10...Circuit board, 8...Solder bump electrode.

Claims (3)

[Claims] (1) In a method for mounting a semiconductor device on a terminal electrode portion on a circuit board, a convex bump electrode having a two-stage shape of a pedestal portion and a top portion is provided on an electrode pad portion of the semiconductor device, and the bump electrode is mounted on a terminal electrode portion of a circuit board. 1. A method for mounting a semiconductor device, comprising electrically connecting to a terminal electrode portion on a circuit board via a flexible conductive adhesive. (2) The method for mounting a semiconductor device according to claim 1, wherein the bump electrode is made of Au. (3) Claim 1, characterized in that the conductive adhesive is made of an epoxy-based, polyimide-based, acrylic-based, phenol-based, or silicone-based conductive adhesive with flexibility added. A method for mounting the semiconductor device described.