JPH10135386A - Manufacturing methd of semiconductor bare chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain semiconductor bare chips having radiation plates integrated therewith, by such a simple procedure that after sticking one radiation plate on a wafer, the resultant product is merely divided into the bare chips. SOLUTION: On a wafer 1, electronic circuits are formed in a predetermined array. Then, to the rear surface of the wafer 1, a bonding material 2 is applied with a uniform thickness. As the bonding material 2, there is used a silicon bonding material having both an elasticity capable of absorbing a stressed strain caused by the difference between thermal expansion coefficients and an excellent thermal conductivity. Then, on the coated surface of the wafer 1 with the bonding material 2, a radiation plate 3 having the same outer diameter as the wafer 1 and made of a thermally conductive metal is so stuck that no bubble is included between them. Then, pressing relatively the radiation plate 3 against the wafer 1, the excess bonding material 2 is extruded from between the wafer 1 and the radiation plate 3 to make the thickness of the bonding material 2 as small as possible. Then, dividing the wafer 1 with the stuck radiation plate 3 thereon into individual chips by lines L laid along the boundaries among the formed circuits, semiconductor bare chips 4 are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor bare chip connected to a circuit board or the like by a flip chip bonding method.

[0002]

2. Description of the Related Art A semiconductor bare chip of this kind is subjected to processes such as diffusion, opening, wiring, electrode formation, formation of a protective film, and inspection of electrical characteristics in a wafer state, and then the wafer is subjected to a dicing method or a scriber method. It is manufactured by separating into individual chips.

As a measure for radiating the heat of the semiconductor bare chip, a method of mounting the semiconductor bare chip on a circuit board and then attaching a heat radiating plate thereto through a heat radiating grease or the like is generally adopted.

[0004]

Since the above-mentioned conventional heat dissipation measures are of a type in which a heat radiating plate is separately attached to a semiconductor bare chip, it is necessary to prepare heat radiating plates having different sizes and thicknesses for each type of semiconductor bare chip. At the same time, in addition to the work of applying the adhesive and the heat radiation grease, the work of mounting the heat radiating plate is troublesome, and there is a problem that the increase in the cost of retrofitting cannot be denied.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing a semiconductor bare chip which does not require a retrofit of a heat sink.

[0006]

In order to achieve the above-mentioned object, a method of manufacturing a semiconductor bare chip according to the present invention comprises bonding a heat sink through a bonding material to the back surface of a wafer having electronic circuits formed in a predetermined arrangement. Thereafter, the main feature is that the wafer to which the heat sink is attached is separated into individual chips.

According to the method of manufacturing a semiconductor bare chip according to the present invention, a semiconductor bare chip integrally provided with a heat radiating portion can be obtained by a simple procedure in which a heat radiating plate is attached to a wafer and then separated. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, in which 1 is a wafer, 2 is an adhesive, 3 is a heat sink, L is a separation line, and 4 is a semiconductor bare chip.

In manufacturing a semiconductor bare chip, first, as shown in FIG. 1A, a wafer 1 made of silicon, GaAs or the like is diffused, opened, formed with wiring, formed electrodes, formed with a protective film, inspected for electrical characteristics, and the like. IC, LS
Electronic circuits such as I are formed in a predetermined arrangement. The procedure for forming a circuit on the wafer 1 is the same as a well-known procedure, and a description thereof will be omitted.

Next, as shown in FIG. 1B, an adhesive 2 is applied to the back surface (surface opposite to the circuit forming surface) of the wafer 1 with a uniform thickness. Various known adhesives can be used for the adhesive 2, but if solder or brazing material is used, the wafer 1 and the radiator plate 3 are firmly joined, and the stress due to the difference in the coefficient of thermal expansion between the two. Since cracks may be generated due to distortion, it is preferable to use a silicon-based adhesive having elasticity capable of absorbing the stress distortion and having excellent thermal conductivity.

Next, as shown in FIG. 1C, a heat radiating plate having the same outer diameter as the wafer 1, for example, a metal such as gold, silver, or aluminum having good heat conductivity is provided on the surface of the wafer 1 on which the adhesive is applied. Is attached so that air bubbles do not enter. Of course, the adhesive 2 may be applied to one surface of the heat sink 3 and then bonded to the surface of the wafer 1 on the side opposite to the circuit forming surface. The thickness of the heat radiating plate 3 is appropriately selected according to the heat value of the electronic circuit formed on the wafer 1.

Then, before the adhesive is hardened, the heat radiating plate 3 is pressed relatively to the wafer 1, and the excess adhesive 2 is pushed out from between the wafer 1 and the heat radiating plate 3 to reduce its thickness as much as possible. The extruded adhesive is removed after curing.

Next, as shown in FIG.
Is bonded to a wafer 1 along a boundary of a formed circuit by a known dicing method or a scriber method.
To separate the individual chips to obtain a semiconductor bare chip 4 as shown in FIG.

The semiconductor bare chip 4 has a structure in which a rectangular chip portion 4a and a heat radiating portion 4b are vertically coupled via an adhesive layer 4c, and the flip is performed such that the heat radiating portion 4b faces outward. It is connected to a circuit board or the like by a chip bonding method.

According to the above-described embodiment, the semiconductor bare chip 4 integrally provided with the heat radiating portion 4b can be formed by a simple procedure in which the heat radiating plate 3 is attached to the wafer 1 and then separated.
Therefore, there is no need to separately attach a heat sink to the semiconductor bare chip as in the related art, and there is an advantage that an increase in cost associated with the attachment can be avoided.

If a silicon-based adhesive having elasticity and excellent thermal conductivity is used as the adhesive 2, stress distortion due to a difference in thermal expansion coefficient between the wafer 1 and the heat radiating plate 3 is absorbed and cracks are generated. There is an advantage that occurrence can be prevented beforehand.

[0017]

As described in detail above, according to the present invention,
With a simple procedure of simply attaching a heat sink to a wafer and then separating the heat sink, a semiconductor bare chip having an integrated heat sink can be obtained. There is an advantage that there is no trouble and an increase in cost associated with retrofitting can be avoided.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... Adhesive material, 3 ... Heat sink, L ... Separation line, 4 ... Semiconductor bare chip, 4a ... Chip part, 4b ... Heat radiating part, 4c ... Adhesive material layer.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ichitaka Suzuki 6-16-20 Ueno, Taito-ku, Tokyo Taiyo Denki Co., Ltd.

Claims (3)

[Claims] An electronic circuit, comprising: bonding a heat radiating plate to the back surface of a wafer formed in a predetermined arrangement via an adhesive; and separating the wafer bonded with the heat radiating plate into individual chips. A method for manufacturing a semiconductor bare chip. 2. The method for manufacturing a semiconductor bare chip according to claim 1, wherein a heat radiating plate is pressed relatively to the wafer before the adhesive is hardened to push out an excess adhesive. 3. The method for manufacturing a semiconductor bare chip according to claim 1, wherein a silicon-based adhesive is used as the adhesive.