JPS63187652A - Heat-resistant resin seal semiconductor device - Google Patents

Abstract

PURPOSE:To reduce moisture intrusion into a sealing resin while largely minimizing the quantity of infrared absorption of the resin through infrared heating by bonding foil or a board preventing the permeation of moisture with the external surface of the resin. CONSTITUTION:A semiconductor element 1 is fixed to a tab frame 2, and lead pins 3 are connected electrically to the semiconductor element 1 by wires 4. The whole is sealed with a resin 5 with the exception of the external connecting sections of the lead pins 3. Aluminum foil 6 is bonded with the upper surface and lower surface of the resin 5 by adhesives 7. The quantity of moisture in an atmosphere intruding into the resin 5 is reduced largely by the aluminum foil 6 in the structure shown in the figure.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a semiconductor device sealed with resin.

In particular, soldering relates to a structure suitable for preventing resin cracks from occurring due to heating during mounting.

[Conventional technology]

Packages with a structure in which semiconductor elements are sealed with resin have an organic resin as their main component, so they absorb more or less water vapor contained in the atmosphere, but if the amount of moisture absorption increases, it may cause damage to the soldering board, etc. It is known that cranks occur in the resin during connection mounting. This mechanism is described in Oki Electric Research and Development No. 128, Vo 1.52.
As mentioned in No. 4゜P 73-78 (1985) and JP-A-60-208847, the moisture contained in the resin becomes water vapor due to heating during mounting, and the inside of the resin package is heated. It is believed that the water vapor pressure increases, eventually leading to resin cracks. In particular, solder reflow in high-temperature steam of fluorine-based inert liquid (V P S
: Vaper Phase Soldering
) or soldering using infrared heating, etc., the entire resin package is in a high temperature state, so cracks are likely to occur.

As a countermeasure against this problem, it is necessary to control humidity during storage of the resin-sealed semiconductor, and the example shown in the cited document is well known in terms of structure. That is, in FIG. 6, after the semiconductor element 1 is fixed to the tab frame 2 and the lead pins 3 and the semiconductor element 1 are electrically connected by the wires 4, sealing is performed with the resin 5. 5 is provided with a water vapor discharge hole 9 to prevent the water vapor pressure inside the package from increasing during high temperature heating. However, with this structure, atmospheric moisture and contaminants are likely to enter the package through the steam exhaust hole 8, and if gaps exist at the interface between the tab frame 2, semiconductor element 1, and resin 5, corrosion of the metal parts may occur. There is a risk of deterioration of the electrical characteristics of the semiconductor element.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology has a problem in that it is insufficient to ensure O properties against internal metal corrosion and electrical characteristic deterioration due to atmospheric moisture and external contaminants.

An object of the present invention is to provide a thermal package that reduces the amount of moisture absorbed by the resin package without making any structural changes that would cause the above-mentioned problems, and that does not cause resin cracks when heated at high temperatures.

[Means for solving problems]

The above object is achieved by forming a structure in which a foil or plate made of a material capable of preventing moisture from permeating is adhered to one of the upper or lower surfaces of the resin package, or to both the upper and lower surfaces.

[Effect]

The foil or plate bonded to the resin package significantly reduces the surface area of the resin that is in direct contact with the atmosphere, that is, the area for moisture in the atmosphere to penetrate, and since the foil or plate does not allow moisture to pass through, the resin package Inhalation gB1 can be significantly reduced.

Furthermore, if a foil or plate with metallic luster is adhered to the upper surface of the resin package, infrared rays can be reflected during solder reflow by infrared irradiation, thereby suppressing an increase in the temperature of the resin package.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 is a sectional view of a resin-sealed package showing one embodiment of the present invention. FIG. 2 shows the effect of this embodiment. 3 to 5 are sectional views showing other embodiments.

In FIG. 1, a semiconductor element 1 is fixed to a tab frame 2, and lead pins 3 are electrically connected to a semiconductor cable 1 by wires 4. Overall beam 1 ~ pin 3
It is sealed with resin 5 except for the external connection part. resin 5
Aluminum foil 6 is bonded to the upper and lower surfaces of the housing with an adhesive 7. In the structure shown in FIG. 1, the amount of moisture in the atmosphere that enters the resin 5 is significantly reduced by the aluminum foil 6.

Figure 2 shows a sample with the structure shown in Figure 1, and for comparison,
After absorbing moisture in three types of samples: a sample without aluminum foil and a sample with aluminum foil attached only to the bottom surface of the resin,
The experimental results obtained by heating by Phase Sol and dering are shown. Humidification conditions are 65℃, 95%R
H, 1687 (Although left unattended, the amount of moisture absorption is reduced by attaching aluminum foil to the bottom surface or both top and bottom surfaces of the resin package. Vaper Pha5e 5o1
The conditions for derin(H) are 215°C and 1150 seconds, but cracks occur in most samples without aluminum foil attached, whereas cracks occur in samples with aluminum foil attached to at least one side of the resin package. It has not occurred.

As mentioned above, by pasting aluminum foil on the front (back) of the resin package, the amount of moisture absorbed by the resin can be kept low, and therefore the Vaper Phase Solde
Since it is possible to suppress the rise in water vapor pressure inside the resin package during high temperature heating such as rir+g, it is possible to prevent the occurrence of resin cracks. Therefore, as a method of pasting the aluminum foil, in addition to the method shown in FIG. Furthermore, although aluminum M is used in this embodiment, since the purpose of Y is to prevent the resin from absorbing moisture, other materials that prevent moisture permeation may also be used. Therefore, it is not necessary to specify the thickness of the plate. In addition, if you attach something with a metallic luster, such as aluminum foil, to the top surface of the resin package, it will reflect the infrared rays and suppress the temperature rise of the resin package. Therefore, a double effect on resin cracks can be obtained.

Next, FIG. 3 shows another embodiment. The aluminum foil 6 attached to the lower surface of the resin 5 has a layer of adhesive 7 on both upper and lower surfaces, and further has an anti-adhesion layer 8 made of paper, for example, attached to the lowermost surface. When connecting this package to a printed circuit board or the like, only the anti-adhesion layer 8 can be removed and the package can be temporarily fixed in a predetermined position with adhesive 7.

Next, FIG. 4 shows another embodiment. An insulator layer 10 having high electrical insulation properties, such as an organic film, is applied to the surface of the aluminum foil 6 to be attached to the surface of the resin 5. The insulating layer 10 has the effect of preventing electrical contact between the aluminum foil 6 and wiring on the printed circuit board or other components.

Next, FIG. 5 shows an example using a material other than metal that prevents moisture permeation. An alumite foil 11 is placed on the surface of the resin 5.
is pasted with adhesive 7. The alumite foil 11 has high electrical insulation, and this embodiment has the same effect as the embodiment shown in FIG. 4 described above.

In the embodiments shown in FIGS. 1 to 5 above, only the so-called surface mount type, in which lead pins are not inserted into holes in the board, is shown as a form of connection to a printed circuit board, etc., but it is of course limited to this. Instead, the present invention can also be applied to so-called insertion-type packages, which connect by inserting lead pins into holes in the board.

〔Effect of the invention〕

According to the present invention, it is possible to reduce moisture intrusion into the resin of a resin-sealed semiconductor device. Furthermore, the amount of infrared absorption of the resin during infrared heating can be significantly reduced. Therefore, soldering has the effect of preventing cracks that occur in the resin during connection and mounting.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a resin-sealed semiconductor device according to an embodiment of the present invention, FIG. 2 is experimental data showing the effect of the embodiment of FIG. 1, and FIGS. 3 and 5 are other embodiments. FIG. 2 is a longitudinal cross-sectional view of a resin-sealed semiconductor device of FIG. FIG. 6 is a longitudinal cross-sectional view showing the prior art. 1... Semiconductor element, 2... Tab frame, 3...
Lead pin, 4... wire, 5... resin, 6...
aluminum foil. 7. Adhesive, 8.. Adhesion prevention layer, 9.. Water vapor discharge hole. 10... Insulator layer, 11... Alumite foil. Figure 1 Figure 2 Figure % VPS: Vaper'phtbse 5olAe
rrn>! Handwriting 1 is accepted) 2 Tough-up to 3 Reading 4 Waguya
Da ta I3 fraud 2 Anomumi foil 7 + '4
f'l 6'+47Lt-row
'? ) RQIAqBL + Figure 70 - Insulator layer Figure 5 / - 11 Almabut negative

Claims (1)

[Claims] 1. A heat-resistant resin-sealed semiconductor device in which a semiconductor element is sealed with resin, characterized in that a foil or plate for preventing moisture permeation is adhered to the outer surface of the sealing resin. .