JPS6237534B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to resin pellets for encapsulating semiconductor devices.

Conventionally, materials for encapsulating semiconductor devices include resin tablets obtained by cold-forming thermosetting resin composition powder; , the cured product is the first
As shown in the figure, the center part bulges thickly due to the effect of surface tension when the resin melts, making it unsuitable for sealing semiconductor elements that require thin sealing thickness, and printing terminal numbers etc. on the surface of the cured product. It had some disadvantages that made it difficult to understand.

In FIG. 1, 1 is a substrate, 2 is a semiconductor element, and 3 is a cured product.

In addition, since the resin tablets are only mechanically bonded together, the strength of the resin tablets is very low, and they are easily damaged during transportation and handling. The ratio was high and it was uneconomical.

Further, in order to seal the case 10 and the upper cap 11 of a cavity package type semiconductor device as shown in FIGS. 3A and 3B, a cold molded resin is used in which holes are formed in the dense areas of the external leads 12a and 12b. Using a cold-molded resin tablet with an elongated shape that fits the gap between the tablet and 12b,
After setting this on top of the upper cap 11, it was heated and melted and hardened, but with this method,
It has the disadvantage that the work is complicated.

In order to improve this drawback, the applicant previously proposed a single-sided sheet-covered resin tablet made by pasting a sheet of paper, polyester film, polyimide film, etc. on one side of a cold-molded resin tablet. Essentially, since cold-molded resin tablets are used, the content of continuous pores is extremely high, and as a result, the tablets tend to absorb heat, and voids tend to remain in the cured product after heating and melt-sealing, and they are difficult to handle. However, the tablet part sometimes gets damaged when it is hit by a shot, etc.

As a result of various studies in order to improve these drawbacks, the present inventors have found that a molten solid layer of a thermosetting resin composition is provided on a sheet-like fiber base material by being fused and integrated with the base material. This problem was solved by using resin pellets for encapsulating semiconductor devices.

In the present invention, the sheet-like fiber base material includes nonwoven fabrics made of various materials, such as polyester nonwoven fabrics,
Organic fiber nonwoven fabrics such as glass paper, inorganic fiber nonwoven fabrics such as glass fiber nonwoven fabrics, cellulose-mixed glass paper, paper, etc. are used.

The sheet-like fiber base material preferably has a softening temperature higher than the melting temperature of the thermosetting resin composition.

The thickness of the sheet-like fiber base material is usually 0.05 mm or more, preferably 0.08 mm to 0.3 mm, and the apparent density is usually 0.10 to 0.05.
g/cm ³ , preferably 0.15 to 0.25 g/cm ³ are advantageously used.

The melting temperature of the molten solid layer is usually 40 to 180℃,
Preferably, a temperature of about 60 to 120°C is generally used.

As the thermosetting resin composition, epoxy resin,
Thermosetting resins such as polyester resins, phenol resins, and isocyanate resins, curing agents, and in some cases curing accelerators; pigments such as carbon black, dyes, flame retardant additives, flame retardant aids, fillers, etc. Examples include those made by homogeneously mixing additives.

The resin pellets of the present invention can be obtained, for example, as follows.

That is, as shown in FIG. 4, a thermosetting resin composition that is solid at room temperature is applied onto glass paper 4 while being melted and extruded from a freely moving heating nozzle 5.
A semi-cured molten solid layer 6 may be formed, and while the layer is flexible, it may be punched into a predetermined resin pellet shape.

The glass paper can be preheated during melt extrusion.

The resin pellet thus obtained has a shape as shown in FIG. 5, for example. Of course, the semi-cured molten solid layer is solid at room temperature.

When manufacturing resin pellets, the thermosetting resin composition is impregnated with resin over the entire thickness of the glass paper, only around the surface layer of the glass paper, or impregnated with resin up to about half the thickness of the glass paper. or In this way, the thickness of the semi-hardened molten solid layer in the glass paper and the present invention is set to 0.3 mm to 5 mm.

If the amount is less than 0.3 mm, the resin amount will be too small and the sealing function will be inferior, while if it is more than 5 mm, the resin amount will be too large and the resin will protrude beyond the proper sealing area.

The melt extrusion temperature is adjusted so that the resulting molten solid layer of resin pellets does not become a completely cured product. A semi-hardened state means that when heated, it temporarily becomes fluidized and then hardens.

In the production of the above-mentioned resin pellets, it is possible to use a thermosetting resin composition that is already in a semi-cured state, or it is also possible to use a semi-cured thermosetting resin composition that is liquid at room temperature. When it becomes a solid layer, it is also possible to use a material that becomes solid at room temperature. This is done by adjusting the conditions of heat application of the heating nozzle.

Further, the resin pellets of the present invention can also be obtained by a thermal spraying method using a thermosetting resin composition powder.

Furthermore, a thermosetting resin composition powder is sprinkled onto the nonwoven fabric (for example, by electrostatic coating), heated and melted to form a semi-cured molten solid layer on the nonwoven fabric, and the layer and the nonwoven fabric are fused and integrated. It can also be manufactured by providing it in a solid state.

Of course, in the present invention, the semi-cured molten solid layer is provided on only one side of the sheet-like fiber base material by being fused and integrated, as shown in FIG. It's okay.

As the sheet-like fiber base material, in addition to nonwoven fabrics, woven fabrics made of various materials can also be used.

Examples of sealing semiconductor devices using resin pellets obtained according to the present invention will be described below.

When the semiconductor element on the substrate is sealed, as shown in FIG. 6, the area where the sheet-like fiber base material is present becomes flat.

Furthermore, in order to seal a semiconductor device as shown in FIGS. 3A and 3B, a resin pellet having a shape as shown in FIG. When used as a resin pellet, sealing can be performed with a single resin pellet (the external lead and the hollow part 7 are aligned and set, and then heated and cured), and the surface of the cured product becomes flat. Furthermore, the seventh
In the figure, 7 is the hollow part of the resin pellet.

As described above, according to the resin pellet of the present invention, since the molten solid layer is a thermosetting resin composition that is melted and then solidified, it has numerous continuous pores like a cold-formed tablet. I haven't done it,
Therefore, it has excellent moisture absorption resistance and mechanical strength during storage. Furthermore, since it is not a cold-formed product and has a molten solid layer, it is difficult for air bubbles to occur during sealing, and as mentioned above, it has excellent moisture absorption resistance during storage, so it has a good sealing function after sealing. It is.

In addition, since the molten solid layer is fused and integrated with the fiber structure of the sheet-like fiber base material, it has excellent adhesion to the base material.In this respect, the strength of the resin pellet itself is extremely high, and the resin Even if the shape of the pellet is complicated as shown in FIGS. 2, 5, and 7, the resin pellet will not be damaged during transportation.

Furthermore, as mentioned above, the resin pellets of the present invention have extremely high mechanical strength, so when performing sealing work,
There is no damage and the sealing workability is good.

Furthermore, in the present invention, since a fiber base material is used as the sheet-like base material instead of something like a plastic film, even if air bubbles are generated in the heated melt of the molten solid during the sealing process, even if bubbles are generated during heating, It has the effect of escaping through the porous layer of the fibrous base material, but when a plastic film is used instead of the sheet-like fibrous base material, the film becomes an obstacle and prevents the generated bubbles from escaping.

Further, as mentioned above, the sheet-like fiber base material is fused and integrated with the molten solid layer, and the molten solid layer has high mechanical strength as described above. Since it acts as a reinforcing base material, the mechanical strength of the entire resin pellet is extremely good.
Therefore, even when encapsulating a semiconductor device as shown in FIGS. 3A and 3B, there is no need to use multiple cold-formed resin tablets as in the prior art, and it is possible to encapsulate the semiconductor device with only one resin pellet. It becomes possible to seal it.

Moreover, since there is a sheet-like fiber base material, if the molten solid layer is fused and integrated on one side of the sheet-like fiber base material and the sealing operation is performed with the base material facing upward, it will harden. The surface of the cured product becomes flat, making it suitable for sealing semiconductor elements that require a thin sealing thickness, and making it easy to print terminal numbers, etc. on the surface of the cured product. Further, if desired, printing can be performed on the sheet-like fiber base material in advance before the molten solid layer is fused and integrated.

Although the present invention has so far been described as a resin pellet for sealing semiconductor elements, the resin pellets of the present invention can be used to seal other objects.
It also includes electrical components other than semiconductor devices, such as small electrical components such as relays and switches, which have a base cap and an upper cap as shown in FIG. 3, and have protruding external leads (terminals).

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram for explaining a conventional method for encapsulating semiconductor devices, Fig. 2 is a perspective view of a cold-molded resin tablet conventionally used for encapsulation, and Fig. 3A is an illustration of a semiconductor device. Explanatory drawings used to explain the sealing method. FIG. 3B is a cross-sectional view of FIG. 3A taken along the line -' and viewed from the direction of the arrow. FIG. 4 illustrates an example of manufacturing the resin pellets of the present invention. 5 and 7 are perspective views showing examples of the resin pellets of the present invention, and FIG. 6 is a sectional view of a semiconductor device after encapsulation using the resin pellets of the present invention. It is. 4...Nonwoven fabric, 6...Semi-cured molten solid layer.

Claims (1)

[Claims] 1. Electrical devices, such as semiconductor devices, in which a semi-cured molten solid layer of a thermosetting resin composition with a thickness of 0.3 mm to 5 mm is fused and integrated on a sheet-like fiber base material. Resin pellets for parts sealing.