JP2703209B2 - Electronic component sealing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode (LE).
D) and a method of sealing electronic components such as integrated circuits (ICs). More specifically, when sealing a sealing component of an electronic component such as a light emitting diode or an integrated circuit with a sealing resin, After applying a specific surface treatment agent in advance, sealing with a sealing resin protects and reinforces the sealing portion, and improves the adhesion between the sealing portion and the sealing resin. The present invention relates to a method for sealing electronic components such as diodes and integrated circuits. BACKGROUND OF THE INVENTION A light emitting diode has a semiconductor chip mounted on a metal lead frame to which a wire such as a gold wire is connected, and then sealed with a sealing resin such as an epoxy resin. It is manufactured by molding into a lens shape or other shapes. Also, a chip-shaped electronic component such as an IC has a gold wire or a lead frame sealed with a sealing resin such as an epoxy resin. In order 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, in order to seal such electronic components with an epoxy resin, there is a problem that the epoxy resin is a thermosetting resin, so that an injection molding method cannot be employed, resulting in poor productivity. For this reason, studies are being made to seal such electronic components by injection molding a thermoplastic resin such as polyphenylene sulfide, liquid crystal polymer, or polyimide. However, when an electronic component such as a light emitting diode or an IC is sealed by injection molding of a thermoplastic resin, it is more difficult to seal the electronic component with a conventional epoxy resin due to pressure during injection molding. However, there have been serious problems that wires such as gold wires of electronic components are liable to be cut or deformed several times, and the lead frame or the semiconductor element may be damaged. Therefore, when an electronic component is to be sealed 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, in Japanese Patent Application Laid-Open No. 54-48186, an electronic component such as a semiconductor element portion is coated with a resin in advance. Then, a sealing method has been proposed. 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. SUMMARY OF THE INVENTION An object of the present invention is to solve the problems associated with the prior art as described above, and a sealing portion of an electronic component such as a light emitting diode or an IC is sealed with a sealing resin. When sealing, protect and reinforce those parts that are easily cut or deformed, such as wires, lead frames, and semiconductor elements, so that cracks do not occur in the sealed parts and injection An object of the present invention is to provide a method for sealing an electronic component that can be formed. SUMMARY OF THE INVENTION According to the method for sealing an electronic component of the present invention, when the sealing portion of the electronic component is sealed with a sealing resin, the propylene content is 55 to 75 mol%, and the X-ray diffraction is performed. An unsaturated carboxylic acid or a derivative thereof is graft-polymerized in an amount of 0.5 to 15% by weight to an unmodified propylene-α-olefin copolymer having a crystallinity of 0 to 20% by the following method. _[0 ] is 0.3 dl / g or more, and a surface-treating agent (B) containing a graft-modified propylene-α-olefin copolymer is applied to a sealing portion in advance, and then sealed with a sealing resin. It is characterized by doing. 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. Since sealing is performed with the sealing resin, the adhesion between the sealing portion such as a wire and the surface treatment agent is remarkably excellent, so that no crack is generated between the sealing portion and the sealing resin. Moreover, there is no breakage or deformation of the wire and the like. 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. Electronic components sealed by the present invention include light emitting diodes, ICs, etc.
Includes all that are sealed with resin. 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 the sealing portion of the electronic component as described above is sealed with a sealing resin, the following surface treatment agent (B) is applied to the sealing portion in advance. After letting
It is sealed with a sealing resin. This surface treating agent (B) is used for preparing a propylene-α-olefin copolymer having a propylene content of 55 to 75% by mole and a crystallinity of 0 to 20% by X-ray diffraction. When the acid or its derivative is 0.5 to 1
It is composed of 5% by weight of a graft copolymerized modified propylene-α-olefin copolymer. And this modified propylene-
The intrinsic viscosity [η ₀ ] of the α-olefin copolymer is 0.3 dl /
It must be at least g. The modified propylene-α-olefin copolymer comprises propylene and ethylene, 1-butene, 4-methyl-1-
Α- such as pentene, 1-hexene, 1-octene, 1-decene
First, unmodified propylene-α-
It is obtained by preparing an olefin copolymer and then graft-modifying this unmodified propylene-α-olefin copolymer. Further, among the unmodified propylene-α-olefin copolymers, a random copolymer of propylene and ethylene is preferred. The propylene content in the unmodified propylene-α-olefin copolymer is in the range of 55 to 75 mol%, preferably 60 to 70 mol%. Also,
Its intrinsic viscosity [η ₁ ] (at 135 ° C in decalin) is from 0.3 to
20 dl / g, preferably in the range of about 0.3 to 10 dl / g. The unmodified propylene-α-olefin copolymer has a crystallinity of about 2 as measured by X-ray diffraction.
-20%, particularly preferably in the range of about 5-18%.
When the propylene content or the intrinsic viscosity [η ₁ ] of the unmodified propylene-α-olefin copolymer deviates from the above range, the adhesion between the sealing portion such as a wire and the surface treatment agent (B) becomes poor. May decrease. The surface treating agent (B) used in the present invention comprises:
It contains a graft-modified unmodified propylene-α-olefin copolymer as described above. The modifier for graft copolymerization with the unmodified propylene-α-olefin copolymer is an unsaturated carboxylic acid or a derivative thereof. The unsaturated carboxylic acids or derivatives thereof used herein include acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid _TM (endocis-bicyclo Unsaturated carboxylic acids such as [2,2,1] hept-5-ene-2,3-dicarboxylic acid) or derivatives thereof,
Examples include acid halides, amides, imides, anhydrides, esters and the like. Examples of the unsaturated carboxylic acid ester used for the graft modification include mono-lower alkyl esters and di-lower alkyl esters of the unsaturated carboxylic acids. 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,
Examples include dimethyl maleate and glycidyl maleate. Of these, unsaturated dicarboxylic acids or their anhydrides are preferred, and maleic acid, nadic acid _TM or their anhydrides are particularly preferred. A known method for grafting the above graft component to an unmodified propylene-α-olefin copolymer, for example,
-185655 can be adopted. That is, for example, the modified propylene-α-olefin copolymer is obtained by
The α-olefin copolymer is obtained by dissolving the copolymer in an organic solvent, adding an unsaturated carboxylic acid or a derivative thereof and a radical generator and heating with stirring. At this time, it is preferable to sequentially add the unsaturated carboxylic acid or its derivative and a radical generator to the solution, so that precipitation or gelation of the modified propylene-α-olefin copolymer can be prevented, and unmodified Unsaturated carboxylic acid or its derivative can be graft-copolymerized homogeneously with the propylene-α-olefin copolymer of (1). The above grafting reaction is carried out, for example, by employing the following conditions. An unmodified propylene-α-olefin copolymer is dissolved in 1 m ^{3 of} an organic solvent by dissolving 10 to 500 kg, particularly preferably 100 to 400 kg, of an unmodified propylene-α-olefin copolymer such as a propylene-ethylene copolymer. Prepare the combined solution. To this solution, an unsaturated carboxylic acid or a derivative thereof is successively added at a rate of 1 to 100 mmol / min / kg-polymer, preferably 2 to 20 mmol / min / kg-polymer. Similarly, the radical dispersing agent is also preferably added sequentially,
The rate of addition is about 5 × 10 ^-5 to 50 mmol / min / kg-polymer, preferably about 10 ^{-2 to} 5 mmol / min / kg-polymer. In this reaction, the molar ratio of radical initiator to unsaturated carboxylic acid or derivative thereof is about 1/100
３ to ／, particularly preferably about 1/20 to １ ／. This grafting reaction is preferably carried out by heating the propylene-α-olefin copolymer solution and under strong stirring. The reaction temperature is preferably from the melting point of the unmodified propylene-α-olefin copolymer to 100 ° C., particularly preferably in the range of 120 to 160 ° C., and the reaction time is usually about 2 to 10 hours. The reaction may be carried out in either a batch system or a continuous system, but a batch system is preferred in order to perform the grafting uniformly. When the above method is employed, the formation of a homopolymer of a graft modifier such as an unsaturated carboxylic acid is extremely suppressed, and the unreacted monomer or radical initiator remaining at the end of the reaction and the decomposition product thereof are reduced. The ratio can also be reduced slightly. Graft-modified propylene thus obtained
The grafting amount of the unsaturated carboxylic acid or its derivative in the -α-olefin copolymer is in the range of 0.5 to 15% by weight, preferably 3 to 10% by weight. The thus obtained graft-modified propylene-α-olefin copolymer is, for example, toluene,
Usually dissolved in a solvent such as methylcyclohexane
Used as 0% by weight of the surface treatment agent (B). In order to apply the surface treatment agent (B) to the sealing portion of the electronic component by using the surface treatment agent as described above, the sealing portion of the electronic component is applied to the surface treatment agent (B), for example. Just dipping. According to the present invention, when an electronic component is sealed, an epoxy or acrylic adhesive is applied to a sealing portion of the electronic component, and then a surface treatment agent (B) is applied. The adhesion between the sealing portion and the surface treatment agent can be further improved. According to the method of sealing an electronic component of the present invention, a specific surface treatment agent is applied to easily breakable portions of wires, lead frames, semiconductor elements, etc. of electronic components such as light emitting diodes and ICs. Since the resin is sealed with the sealing resin after being attached, the adhesiveness between the sealing portion such as a wire and the surface treatment agent is remarkably excellent, so that a crack is formed between the sealing portion and the sealing resin. There is no occurrence of breakage or deformation of the wire or the like. For this reason, an electronic component can be extremely efficiently manufactured by injection molding. The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the scope of the invention. Example 1 An unmodified propylene-ethylene copolymer having a propylene content of 60 mol% (intrinsic viscosity [η ₁ ] = 1.1 dl /
g) was graft-polymerized with 7% by weight of maleic anhydride to obtain a graft-modified propylene-ethylene copolymer having an intrinsic viscosity [η ₀ ] of 1.1 dl / g (crystallinity by X-ray diffraction = 7.
8%). This modified propylene-ethylene copolymer was dissolved in n-hexane at a concentration of 12.3% by weight to prepare a surface treating agent. Hereinafter, this surface treatment agent (I) will be referred to as “surface treatment agent (I)”. The surface treating agent (I) is applied to the semiconductor chip portion, the fine 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 0.2 g.
After being applied in an amount of 3 g, it was naturally dried for 10 minutes or more in an environment of a temperature of 23 ° C. and a humidity of 50%. Next, the lead frame to which the surface treatment agent was applied as described above was set in an injection mold. Separately, the MFR is 70 g / min and the 1-decene content is 3.0.
4% by weight of a 4-methyl-1-pentene / 1-decene copolymer was prepared, and the 4-methyl-1-pentene / 1-decene copolymer was injected into an injection molding machine (type: M-100, ( Co., Ltd.), molding temperature 310 ° C, injection pressure 20Kg / cm ² G,
Injection molding was performed under the conditions of 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 exhibited a good appearance without any damage to the semiconductor chip and no break in the gold wire. The following methods were used to evaluate the adhesion between the surface treatment agent (I) and the lead frame, heat cycle resistance, and the like. Adhesion test : The light emitting diode was immersed in the red ink solution, boiled for 1 hour, then removed from the red ink and washed.
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 portion ×: internal penetrating into the vicinity of the semiconductor chip inside the sealing portion Heat cycle test :- After leaving in an atmosphere of each temperature of 30 ° C., 20 ° C., and 100 ° C. for 30 minutes, and repeating this for 30 cycles, a current of 30 mA was passed through to cut and break the gold fine wire and visually check the interface of the sealed portion. The occurrence of cracks was evaluated. (Evaluation method) ○: no encapsulation cracks at the interface and energization possible Δ: encapsulation is possible only at the interface section racks of the encapsulation ×; . Comparative Example 1 MFR was used without using the surface treatment agent (I).
Was carried out in the same manner as in Example 1 except that a 4-methyl-1-pentene / 1-decene copolymer having a content of 70 g / 10 min was used. The obtained encapsulated light emitting diode (II) was evaluated by the method described in Example 1. Table 1 shows the results. Comparative Example 2 As in Comparative Example 1, the MFR was 26 g / 10 min.
Example 1 was repeated except that the 4-methyl-1-pentene / 1-decene copolymer was used, but the gold wire inside the sealing was cut off and did not function as a light emitting diode. [Table 1]

Claims (1)

(57) [Claims] When sealing the sealing portion of the electronic component with the sealing resin, the propylene content is 55 to 75 mol%,
An unsaturated carboxylic acid or a derivative thereof is graft-polymerized in an amount of 0.5 to 15% by weight to an unmodified propylene-α-olefin copolymer having a crystallinity of 0 to 20% by X-ray diffraction. After applying a surface-treating agent (B) containing a graft-modified propylene-α-olefin copolymer having a viscosity [η ₀ ] of 0.3 dl / g or more to a sealing portion in advance,
A method for sealing an electronic component, which comprises sealing with a sealing resin. 2. The unmodified propylene-α-olefin copolymer has a crystallinity of 5-18 as measured by X-ray diffraction.
%. 3. The intrinsic viscosity of the unmodified propylene -α- olefin copolymer [eta _1] is, 0.3~20dl / g sealing method as in claim 1 wherein in the range of.