JP2571235B2 - Electronic component sealing method - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to light emitting diodes (LEDs), integrated circuits (ICs)
More specifically, when a sealing component of an electronic component such as a light emitting diode or an integrated circuit is sealed with a sealing resin, a specific surface treatment agent is applied to the sealing portion in advance. After being attached, sealing with a sealing resin protects and reinforces the sealed part,
The present invention relates to a method for sealing an electronic component such as a light emitting diode and an integrated circuit, in which the sealing portion and the sealing resin have good adhesion.

Technical background of the invention and its problems Light-emitting diodes are manufactured by mounting a semiconductor chip on a metal lead frame to which a wire such as a gold wire is connected, and then sealing with a sealing resin such as epoxy resin to form a lens or other It is manufactured by molding into a shape. In addition, a chip-shaped electronic component such as an IC is also sealed with a gold wire or a lead frame by a sealing resin such as an epoxy resin.

By the way, to seal electronic components such as light emitting diodes or ICs with a sealing resin, an epoxy resin which is a thermosetting resin has been mainly used. However, to seal such electronic components with epoxy resin,
Since the epoxy resin is a thermosetting resin, the injection molding method cannot be adopted, and there is a problem that productivity is poor. For this reason, for example, polyphenylene sulfide,
Research for sealing the above electronic components by injection molding a thermoplastic resin such as a liquid crystal polymer or a polyimide has been advanced.

However, when trying to seal electronic components such as light emitting diodes or ICs by injection molding of thermoplastic resin,
Due to the pressure during injection molding, the wires such as the gold wires of the electronic components are more likely to be cut or deformed than in the case where the electronic components are sealed with the conventional epoxy resin. However, there was a serious problem that the device could be damaged. Therefore, when trying to seal electronic components by injection molding,
It is necessary to protect a wire such as a gold wire, a lead frame, and a semiconductor element more than when an electronic component is sealed with an epoxy resin.

In order to protect such a wire such as a gold wire, a lead frame and a semiconductor element, for example, Japanese Patent Application Laid-Open No.
Japanese Patent Publication No. 186 proposes a method in which an electronic component such as a semiconductor element portion is previously covered with a resin and then sealed. However, according to the method disclosed in this publication, since the joint between the sealing resin and the metal such as a wire is not firmly bonded, cracks may occur at the interface, or moisture may enter from the cracks and cause corrosion of the metal. And the reliability of the electronic member is greatly reduced.

Object of the Invention The present invention is to solve the problems associated with the prior art as described above, and when sealing a sealing portion of an electronic component such as a light emitting diode or an IC with a sealing resin. Protects and reinforces the easily cut or deformed portions of the sealing portions of wires, lead frames, semiconductor elements, etc., so that cracks do not occur in the sealing portions, and injection molding is possible. An object of the present invention is to provide a method for sealing such electronic components.

SUMMARY OF THE INVENTION The method for encapsulating an electronic component according to the present invention includes the steps of, when sealing a sealing portion of the electronic component with a sealing resin, obtaining an unsaturated carboxylic acid or a derivative thereof in an unmodified propylene polymer. Saponification value of the modified propylene polymer is 5
Modified propylene polymer having a limiting viscosity [η] of 0.1 to 5 dl / g, which is chlorinated so that the chlorine content is 10 to 50% by weight, which has been graft-polymerized to fall within the range of 150 mg. A surface treatment agent (A) containing a chlorinated polymer is applied to a sealing portion in advance and then sealed with a sealing resin.

According to the method for sealing an electronic component such as a light emitting diode or an IC according to the present invention, a sealing resin is applied after a specific surface treatment agent is applied to easily breakable portions such as wires, lead frames, and semiconductor elements. , The adhesion between the sealing portion such as a wire and the surface treatment agent is remarkably excellent, so that no cracks or the like occur between the sealing portion and the sealing resin, and the wire No damage or deformation occurs. For this reason, an electronic component can be extremely efficiently manufactured by injection molding.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a method for sealing an electronic component according to the present invention will be specifically described.

The electronic components sealed by the present invention include all components sealed with resin, including light-emitting diodes and ICs. Such an electronic component generally has a structure in which a wire such as a metal is connected to a lead frame, and a semiconductor element (IC chip) is mounted on the lead frame.

In the present invention, when a sealing portion of an electronic component as described above is sealed with a sealing resin, a surface treatment agent (A) as described below is applied to the sealing portion in advance. , And is sealed with a sealing resin.

The surface treating agent (A) used in the present invention comprises a chlorinated modified propylene polymer.

In preparing the modified propylene polymer chloride, first, a modified propylene polymer is prepared by graft copolymerizing an unsaturated carboxylic acid or a derivative thereof with an unmodified propylene polymer. The saponification value of this modified propylene polymer is in the range of 5 to 150 mg / g. Then, the decalin solvent for the modified propylene polymer
The intrinsic viscosity [η] measured at 135 ° C. is in the range of 0.1 to 5 dl / g.

The chlorinated modified propylene polymer used as the surface treatment agent (A) in the method of the present invention is a chlorinated modified propylene polymer having the above-mentioned properties when the chlorine content is within the range of 10 to 50% by weight. It is obtained by chlorination as follows. When the chlorine content is more than 50% by weight, the chlorinated modified propylene polymer becomes hard and brittle, and the peel strength of the sealing resin does not become sufficiently high. Also, the solvent resistance is reduced.
Further, the coloring of the obtained chlorinated modified propylene polymer becomes remarkable, and the amount of free chlorine also increases, and the element tends to deteriorate due to the free chlorine. On the other hand, in the present invention, the surface treatment agent (A) is used by dissolving the chlorinated modified propylene polymer in an organic solvent such as toluene, methyl isobutyl ketone, and methylcyclohexane. Chlorine content of 10% by weight
If it is less than the above, the solubility of the chlorinated modified propylene polymer is low, and the surface treatment of the sealed portion of the adhered portion cannot be performed efficiently.

In the present invention, the composition of the unmodified propylene polymer used for the preparation of the surface treatment agent containing the chlorinated modified propylene polymer as described above has a propylene component unit of usually 70 to 100 mol%, Preferably 85 to 100 mol%
Is an α-olefin component unit other than propylene,
Usually, it is 0 to 30 mol%, preferably 0 to 15 mol%.

Here, as the α-olefin other than propylene, for example, ethylene, 1-butene 1-pentene, 1-hexene, 2-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, -Heptene, 1-octene and the like are used. Among these α-olefins, those using ethylene and 1-butene are preferred. These α-olefins other than propylene may independently constitute a propylene polymer together with propylene, or two or more thereof may be constituent components of the propylene polymer together with propylene. Further, the propylene-based polymer may be a random copolymer of each constituent unit or various block copolymers. Preferred examples of the propylene-based polymer include isotactic polypropylene, propylene-ethylene copolymer, propylene-1-butene copolymer and the like.

The unmodified propylene-based polymer may further contain a component unit derived from a copolymerizable monomer such as acrylic acid, an acrylate, vinyl acetate, vinyl alcohol, and vinyl chloride, in addition to the above component units.

The modified propylene-based polymer is obtained by graft copolymerization of the above-mentioned unmodified propylene-based polymer with an unsaturated carboxylic acid or a derivative thereof, and the saponification value needs to be in the range of 5 to 150 mg / g. And particularly preferably in the range of 30 to 100 mg / g. The intrinsic viscosity [η] of the modified propylene polymer needs to be in the range of 0.1 to 5 dl / g, and preferably in the range of 0.2 to 3 dl / g.

If the saponification value or intrinsic viscosity [η] of the modified propylene polymer is out of the above range, the adhesiveness between the sealing portion such as a wire and the surface treatment agent (A) decreases, which is not preferable. .

As the unsaturated carboxylic acid or its derivative used when graft-modified an unmodified propylene polymer, acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid,
Unsaturated carboxylic acids such as isocrotonic acid and nadic acid _TM (endosis-bicyclo [2,2,1] hept-5-ene-2,3-dicarboxylic acid) or derivatives thereof, for example, acid halides, amides, imides, anhydrides Products, esters and the like.

Here, as the ester of the unsaturated carboxylic acid used for the graft modification, a mono-lower alkyl ester or a di-lower alkyl ester of the unsaturated carboxylic acid can be exemplified. Here, specific examples of the lower alkyl group include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Among these esters of unsaturated carboxylic acids, maleic acid mono-lower alkyl esters are preferred.

Further, specific examples of the compound used for graft modification include maleenyl chloride, maleimide, maleic anhydride,
Citraconic anhydride, monomethyl maleate, dimethyl maleate, glycidyl maleate and the like.

Among these, unsaturated dicarboxylic acids or acid anhydrides thereof are preferable, and maleic acid, nadic acid _TM or acid anhydrides thereof are particularly preferable.

The graft component is graft-polymerized to an unmodified propylene-based polymer by a known method, for example, a method described in
The method disclosed in Japanese Patent No. 185655 can be employed.

The chlorinated modified propylene polymer is obtained by chlorinating a graft-modified propylene polymer obtained by modifying an unmodified propylene polymer with the above-described graft modifier.

In the chlorination, chlorine gas is introduced into a homogeneous solvent in which the modified propylene polymer prepared as described above is completely dissolved in a solvent. Examples of the solvent used in this case include aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane, tetradecane, and kerosene; and alicyclic hydrocarbons such as methylcyclopentane, cyclohexane, methylchlorohexane, cyclooctane, and cyclodecane. Aromatic hydrocarbons such as hydrogen, benzene, toluene, xylene, ethylbenzene, cumene, ethyltoluene, trimethylbenzene, cymene, diisopropylbenzene,
Examples thereof include halogenated hydrocarbons such as chlorobenzene, bromobenzene, o-dichlorobenzene, carbon tetrachloride, chloroform, bromoform, trichloroethane, trichloroethylene, tetrachloroethane, and tetrachloroethylene. Of these, halogenated hydrocarbons are particularly preferred.

At the time of the chlorination reaction of the modified propylene-based polymer, while thoroughly stirring a homogeneous solution obtained by uniformly dissolving the graft-modified propylene-based polymer in a solvent as described above, adding chlorine gas until a predetermined chlorine content is reached. This chlorine gas is reacted with the graft-modified propylene-based copolymer. When performing the chlorination reaction, a radical generator may be used, or ultraviolet or visible light may be irradiated for the purpose of efficiently proceeding the reaction. As the radical generator, a radical generator used when graft-modifying a propylene-based polymer can be used. However, a method of obtaining a chloride without adding a radical generator or irradiating with ultraviolet rays or visible rays can also be adopted.

The temperature of the chlorination reaction is usually about 50 to 120 ° C, and the reaction time is about 0.5 to 5 hours.

The modified propylene-based copolymer thus obtained is dissolved in a solvent such as toluene, methyl isobutyl ketone, or methylcyclohexane, and is usually used as a surface treatment agent (A) having a concentration of 5 to 30% by weight.

In order to apply the surface treatment agent (A) to the sealing portion of the electronic component using the surface treatment agent as described above, the sealing portion of the electronic component is dipped, for example, to the surface treatment agent (A). Good.

Further, in the present invention, when an electronic component is sealed, an epoxy-based or acrylic adhesive is applied to a sealing portion of the electronic component, and then a surface treatment agent (A) is applied. The adhesion between the part and the surface treatment agent can be further improved.

Effect of the Invention According to the method for sealing an electronic component such as a light emitting diode or an IC according to the present invention, a specific surface treatment agent is applied to a fragile portion such as a wire, a lead frame, or a semiconductor element, and then sealed. It is sealed with a sealing resin, but since the adhesion between the sealing part such as a wire and the surface treatment agent is remarkably excellent, there is no crack between the sealing part and the sealing resin. In addition, the wires and the like are not damaged or deformed. For this reason, an electronic component can be extremely efficiently manufactured by injection molding.

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist thereof.

Example 1 A propylene homopolymer was prepared using maleic anhydride.
The modified propylene-based polymer was prepared by modifying so that the grafted amount of maleic anhydride became 7% by weight. The saponification value of the modified propylene polymer thus modified to a graft amount of 7% by weight is 79 mg / g, and the intrinsic viscosity [η] is 0.6 dl / g.

Next, the modified propylene polymer graft-modified with maleic anhydride was chlorinated so that the chlorine content was 30% by weight, to obtain a chlorinated modified propylene polymer. The intrinsic viscosity [η] of this modified propylene polymer is
0.6 dl / g.

The chlorinated modified propylene polymer was dissolved in n-hexane so as to have a concentration of 12.3% by weight to prepare a surface treating agent. Hereinafter, this surface treatment agent is abbreviated as “treatment agent (I)”.

After applying the treating agent (I) to the semiconductor chip portion, the gold wire portion and the lead frame portion mounted on the lead frame of the light emitting diode in an amount of 0.2 g to 0.3 g,
It was air-dried in an environment at a temperature of 23 ° C and a humidity of 50% for 10 minutes or more.

Next, the lead frame to which the surface treatment agent was applied as described above was placed in an injection mold.

Separately, MFR is 70 g / min and 1-decene content is 3.0
4% by weight of a 4-methyl-1-pentene / 1-decene copolymer was prepared.
The decene copolymer is injected into an injection molding machine (model: M-100, Inc.)
Molding temperature 310 ° C, injection pressure 20Kg / cm
Injection molding was performed under the conditions of ² G, an injection speed of 3 g / sec, and a mold temperature of 40 ° C. to obtain a sealed light emitting diode (I).

The obtained encapsulated light emitting diode (I) showed a good appearance without damage to the semiconductor chip and no break in the gold wire.

The following methods were used to evaluate the adhesion between the treatment agent (I) and the lead frame, the heat cycle resistance, and the like.

Adhesion test: Immerse the light emitting diode in red ink liquid,
After boiling for 1 hour, the ink was taken out of the red ink and washed, and the penetration of the red ink was visually evaluated.

(Evaluation method) ○: no red ink penetrated △: red ink penetrated up to 1 mm from the root of the sealing part ×: penetrated into the vicinity of the semiconductor chip inside the sealing part Heat cycle test: -30 ° C, After leaving for 30 minutes each in an atmosphere of each temperature of 20 ° C and 100 ° C, repeating this for 30 cycles, applying a current of 30 mA rating to cut or break gold wire, and visually check for the occurrence of interface cracks in the sealed part. Was evaluated.

(Evaluation method) ；: no energetic cracks in the sealed portion and energized.

Example 2 The treating agent (I) prepared in Example 1 was previously applied to the semiconductor chip portion and other lead frame portions counted on the lead frame of the light emitting diode in the same manner as in Example 1. After drying under the same conditions as described above, the lead frame to which the treating agent was applied was placed in an injection mold. Next, the lead frame on which the treating agent was applied was sealed with a 4-methyl-1-pentene-1-decene copolymer having an MFR of 26 g / 10 min and a decene content of 3.0% by weight.

The same injection molding machine as that used in Example 1 was used. The molding temperature was 310 ° C., the injection pressure was 25 kg / cm ² G, and the injection speed was 3 g / s.
ec, metal temperature 40 ° C.

The obtained sealed diode (II) was evaluated by the method described in Example 1.

 Table 1 shows the results.

Comparative example 1 It carried out similarly to Example 1 except not using the surface treatment agent (I) but using 4-methyl-1-pentene 1-decene copolymer whose MFR was 70 g / 10min.

The obtained encapsulated light emitting diode (III) was evaluated by the method described in Example 1.

 Table 1 shows the results.

Comparative Example 2 Similar to Comparative Example 1, except that a 4-methyl-1-pentene / 1-decene copolymer having an MFR of 26 g / 10 min was used. The line is cut,
It did not function as a light emitting diode.

Claims (1)

(57) [Claims] 1. An unsaturated carboxylic acid or a derivative thereof is added to an unmodified propylene polymer and a saponification value of the modified propylene polymer obtained when an electronic component is sealed with a sealing resin. Of a modified propylene polymer having an intrinsic viscosity [η] of 0.1 to 5 dl / g, which has been graft-polymerized so as to be in the range of 5 to 150 mg, is chlorinated so that the chlorine content is 10 to 50% by weight. A method for sealing an electronic component, comprising applying a surface treatment agent (A) containing a chlorinated modified propylene polymer to a sealing portion in advance, and then sealing with a sealing resin.