JP2862662B2 - Semiconductor sealing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a semiconductor sealing method used for sealing a conductive element to be mounted on a circuit board on the circuit board.

[Prior art]

In a hybrid integrated circuit, after a conductor pattern is formed on a circuit board, a bare chip is mounted as a semiconductor element together with a passive element such as a resistor. A conductor pattern to be connected to the terminals of the bare chip is formed on the periphery of the bare chip on the circuit board, and the terminals of the bare chip and the conductor pattern are electrically connected to each other by wire bonding like conductor wires. After such an electrical connection is made, a guard ring as a damping frame for damping the sealing resin is formed of the sealing resin in a range surrounding the conductor wire and the bare chip, and the hardening of the guard ring is awaited. Then, the inside is filled with a sealing resin, and the bare resin, the conductor wire and the conductor pattern in the peripheral portion thereof are sealed with the sealing resin.

The guard ring used for resin sealing of such a semiconductor element is for blocking the sealing resin, and ideally has lower fluidity than the sealing resin. Resin is used. From the viewpoint of workability, it is desirable that the guard ring be cured immediately, and a sealing resin capable of setting a sufficient height in a narrow range is desired. Conventionally, a thixotropic resin different from the sealing resin is used for the guard ring, and its adjustment is very troublesome. Even if the resin for guard ring is used, the fluidity is slightly different, and there is no optimal resin for guard ring,
In order to obtain a sufficient height, the amount of dripping per unit area increases, and it spreads due to its fluidity during curing, which causes a reduction in mounting efficiency of components on a circuit board. Therefore, the present invention is to heat the sealing resin forming the guard ring to accelerate the curing, to form an optimal guard ring to realize efficient resin sealing, and to perform a heat treatment for forming the guard ring. It is an object of the present invention to provide a semiconductor encapsulation method that avoids the adverse effects of the above.

[Means for Solving the Problems]

That is, according to the semiconductor sealing method of the present invention, a guard ring (18) is formed around the semiconductor on a circuit board (2) on which a semiconductor element (bare chip 4) is installed, and a sealing resin (16) is formed inside the guard ring (18). In the semiconductor sealing method of sealing the semiconductor by filling the sealing resin, the sealing resin supplied to the circuit board while supplying the sealing resin to a portion of the circuit board where the guard ring is to be formed. Is blown with hot air (28) to be thermally cured, and the hot air blown to the sealing resin is sucked.

[Action]

Since the sealing resin forming the guard ring can be rapidly cured by heating on the circuit board, the curing allows the guard ring having a sufficient height to be formed with a small amount of resin. Further, since the hardening of the guard ring is accelerated and sufficient strength can be obtained in a short time, the sealing resin can be filled immediately after the formation of the guard ring. Then, the hot air blown to the sealing resin for forming the guard ring is sucked from above the guard ring, and the heating of the parts other than the gart ring, particularly, the sealing resin on the sealing resin supply means side is prevented. Thus, deterioration of the sealing resin is prevented.

【Example】

Hereinafter, the present invention will be described in detail with reference to the embodiments illustrated in the drawings. 1 and 2 show an embodiment of the semiconductor sealing method of the present invention. As shown in FIGS. 1 and 2A, a circuit board 2 is formed of an insulating material such as alumina or ceramic, and a bare chip 4 as a semiconductor element should be mounted on the surface of the circuit board 2. A conductor 6 is formed on the portion by printing, and a conductor pattern 8 is formed with a certain interval between the conductors 6. The conductor pattern 8 forms a circuit pattern with circuit components (not shown) and other functional circuits. As shown in FIG. 2B, the bare chip 4 is fixed to the upper surface of the conductor 6 with a conductive adhesive 10 and the semiconductor substrate of the bare chip 4 is electrically connected to the conductor 6. Electrodes formed on the edge of bare chip 4
A conductor wire 14 is connected between the conductor pattern 12 and the corresponding conductor pattern 8 by wire bonding, and is electrically connected. Then, a guard ring 18 is formed with a sealing resin 16 in an area surrounding the bare chip 4 and the conductor pattern 8 to which the conductor wires 14 are connected. That is, as shown in FIG. 1, a syringe 20 is provided as a sealing resin supply means, and the sealing resin 16 is continuously sealed at a tip end thereof by a predetermined amount by pressing the syringe 20 side. A needle 22 for dropping the resin 16 is attached. Therefore, the sealing resin 16 is continuously supplied from the needles 22 to the upper surface of the circuit board 2 in a one-stroke form. It is formed by the stopper resin 16. In the vicinity of the syringe 20, a hot air supply pipe 26 connected to a hot air source 24 is exposed, and the distal end is directed to the vicinity of the needle 22, that is, the sealing resin 16 immediately after dripping from the needle 22. I have. Therefore, the sealing resin 16 dropped on the circuit board 2 is heated by the hot air 28 jetted from the hot air supply pipe 26 and thermally cured. Further, the hot air supply pipe 26 is covered with an intake pipe 32 connected to an intake source 30 that sucks the hot air 28. Intake pipe 32
The hot air supply pipe 26 is expanded toward the distal end thereof in order to expand the suction range of the hot air 28, and in order to increase the suction capacity of the hot air 28.
A tube having a larger inner diameter is used and connected to the intake source 30. That is, the hot air 28 generated by the hot air source 24 is
After being supplied onto the sealing resin 16 through 26, it is sucked into the suction pipe 32 by the suction pressure from the suction source 30, and thus returned from the suction source 30 to the hot air source 24 via the sealing resin 16 to be heated. A loop is formed, and hot air 28 convects between the hot air source 24 and the intake source 30. Then, the sealing resin 16 which has received the hot air 28 is heated by the heat energy from the hot air 28, and is thermally cured by the heating to prevent the flow of the sealing resin 16 as shown in FIG. 2 (C). Guard ring with sufficient height and strength in a narrow range
Formed on 18. Next, the inside of the guard ring 18 is filled with the sealing resin 16 from the needle 22 of the syringe 20 as shown in FIG. 2D, and as shown in FIG. A resin film having a sufficient thickness is formed on the bare chip 4 to complete the resin sealing. In such resin sealing, a guard ring 18 having sufficient strength and height is formed with a small amount of the sealing resin 16 by utilizing the thermosetting of the sealing resin 16, and a sealing ring similar to the guard ring 18 is formed therein. Sealing is performed with the sealing resin 16. In particular, since the sealing resin 16 on which the guard ring 18 is to be formed can be prevented from flowing out by thermosetting, the operation of the syringe 20 is easy and the guard ring 18 with high accuracy is formed. Since the hot air 28 used for this thermosetting is returned from the suction pipe 32 to the hot air source 24 through the suction source 30, the sealing resin 16 before the supply of the syringe 20 and the needle 22 on the sealing resin supply means side is used.
Therefore, the deterioration of the sealing resin 16 before the supply is prevented. Therefore, the reliability of the guard ring 18 is improved. According to the experiment, when epoxy resin is used as the sealing resin 16, the surface temperature of the sealing resin 16 can be raised to 150 ° C. to 200 ° C. by the hot air 28 from the hot air source 24. 16 was thermally cured, and the strength and height sufficient to fill the sealing resin 16 covering the bare chip 4 could be set.

【The invention's effect】

As described above, according to the present invention, the following effects can be obtained. (A) Hot air is blown onto the sealing resin, and the sealing resin is thermally cured by the hot air to form the guard ring. Therefore, the time for forming the guard ring is short, and the guard ring can be filled with the sealing resin immediately. The hardening can be performed to a sufficient degree, the formation of the guard ring and the filling of the inside thereof with the sealing resin can be performed in the same step, so that the manufacturing time can be reduced and the manufacturing cost can be reduced. (B) Since the curing speed of the sealing resin for forming the guard ring can be increased by thermosetting and an ideal guard ring can be formed, the sealing resin for forming the guard ring and the inside of the guard ring are filled. The same sealing resin to be used can be used, and there is no need to use a special sealing resin. Therefore, the manufacturing cost can be reduced from the viewpoint of materials. (C) Unnecessary spreading to the circuit board surface due to the fluidity of the sealing resin for forming the guard ring can be prevented, which can contribute to high-density mounting of the circuit board. (D) Since the hot air applied to the sealing resin for forming the guard ring is sucked and discarded, the heating of the sealing resin to the sealing resin supply means side by the hot air rebounding from the sealing resin can be prevented, and Also, the sealing resin before being supplied to the circuit board can be protected from thermal deterioration due to hot air, and the quality and reliability of the guard ring can be improved.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of the semiconductor sealing method of the present invention, and FIG. 2 is a sectional view showing one embodiment of the semiconductor sealing method of the present invention. 2 Circuit board 4 Bare chip (semiconductor element) 16 Sealing resin 18 Guard ring 28 Hot air

Claims (1)

(57) [Claims] 1. A semiconductor sealing method for sealing a semiconductor by forming a guard ring around the semiconductor on a circuit board on which the semiconductor is mounted, and filling the inside with a sealing resin. While supplying the sealing resin to the portion where the guard ring is to be formed, the sealing resin supplied to the circuit board was blown with hot air to be thermally cured, and was blown to the sealing resin. A semiconductor sealing method, wherein the hot air is sucked.