JPH02237139A - Electronic-component sealed and molded body - Google Patents

Abstract

PURPOSE:To enhance a moistureproof property and a solder heat-resistant property by a method wherein an interface between a sealing PAS resin composition and a lead frame of an electronic component is sealed with a dealcoholized one-liquid type RTV silicone rubber. CONSTITUTION:An interface between a lead frame and/or a lead wire of an electronic component sealed with a polyallylene sulfide (PAS) resin composition and a sealing resin composition is sealed with a dealcoholized one-liquid type room-temperature hardening type silicone rubber whose viscosity before hardening is 0.1 to 800 poise (at 25 deg.C). A resin composition whose molten viscosity (measured at 310 deg.C and at a shearing speed of 10<4>/sec) containing 50 to 95wt.% of PAS and 5 to 50wt.% of a fiberlike filling material is suitable as the PAS resin composition. Thereby, a gap at the interface part is blocked; it is possible to obtain an electronic component sealed and molded body whose moistureproof property and solder heat-resistant property are excellent.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an electronic component encapsulation molded product having excellent moisture resistance and soldering heat resistance, and more specifically, polyarylene sulfide (hereinafter abbreviated as rPAsJ) resin. An electronic component encapsulation molded product formed by encapsulation molding with a composition, in which the interface between the PAS resin composition and a metal part such as a lead frame is sealed (filled) with a specific room temperature curing silicone rubber after encapsulation molding. This relates to an electronic component encapsulation molded product that can withstand the high temperature environment during mounting using the chip method and has high moisture resistance. [Prior art] Electronic components, such as capacitor diodes, transistors rc, LSI, etc., are sealed with synthetic resin for the purpose of maintaining electrical insulation and preventing changes in characteristics due to external atmosphere, as well as for productivity and cost advantages. It is widely practiced to prevent

Conventionally, thermosetting resins such as epoxy resins and silicone resins have been used as synthetic resins for sealing, but they require time to thermoset and have long molding cycles, and there are Deficiencies have been pointed out, including the difficulty in preserving the resin and the inability to reuse the blue runner.

Therefore, in recent years, PAS resin, a thermoplastic resin with excellent heat resistance, flame retardance, and electrical properties, has been developed, and in particular, its representative resin, polyphenylene sulfide (rPPSJ), has been developed.
It has been proposed to use a resin composition mainly consisting of
No. 6-9014, JP-A-57-21844, JP-A-5
7-40557, JP-A-59-20910, JP-A-59-209-11, JP-A-60-40188,
JP-A-62-66351, JP-A-62-197451
No., JP-A-63-146963, JP-A-63-219
No. 145).

However, when sealing is performed with a PAS resin composition, PAS has poor adhesion to the lead frame or lead wire (bonding wire) of electronic components, so if it is placed in a high humidity atmosphere, the sealing resin will not adhere properly. It has the disadvantage that moisture easily enters from the interface with the lead frame, etc., causing a decrease in electrical insulation, corrosion of the lead frame and wires, and deteriorating the electrical characteristics of electronic components.

Further, electronic components sealed with resin are required to be able to deform following the deformation due to thermal expansion of the element to be sealed, and to not cause exterior cracks when immersed in a solder bath.

Furthermore, the encapsulating resin composition is required to have a low viscosity, since high viscosity during molding tends to cause elements to "slip" and bonding wires to come off.

Recently, a method has been proposed to improve moisture resistance by sealing electronic parts with PPS resin and then filling the interface between the lead frame, etc. of the electronic parts and the PPS resin with a low-viscosity adhesive. (Unexamined Japanese Patent Publication No. 62-120036)
Since the adhesives specifically proposed are all acidic substances, there is a risk of corroding metals such as copper, and the adhesive film is hard, so there is a risk of cracking due to thermal expansion.

As described above, electronic component encapsulation molded products are required to have excellent moisture resistance, solder heat resistance, and moldability, but conventional electronic component encapsulation molded products made from PAS resin compositions do not meet these requirements. The improvement effect is still insufficient,
This is an issue that must be resolved before it can be put into practical use.

[Problem to be solved by the invention]

An object of the present invention is to use a PAS resin composition as a sealing resin to obtain an electronic component sealing molded product having excellent moisture resistance and soldering heat resistance.

Another object of the present invention is to use a PAS resin composition with low viscosity and high fluidity to obtain an electronic component encapsulation molded product having excellent moldability, moisture resistance, and soldering heat resistance.

In order to solve the problems of the prior art, the present inventors have conducted extensive research and found that the interface between the lead frame and/or lead wire of an electronic component encapsulated with a PAS resin composition and the encapsulation resin composition has been determined. By sealing with dealcoholized, one-component, room-temperature-curing silicone rubber with a viscosity of 0.1 to 800 poise (25°C) before curing, the gap at the interface is sealed, making it an electronic material with excellent moisture resistance and soldering heat resistance. It has been found that a component fief molded product can be obtained.

In addition, when a PAS resin composition containing a fibrous filler and being flexible at high temperatures is used, it is possible to create electronic component encapsulation moldings with excellent processability, moisture resistance, and soldering heat resistance. I found out what I can get.

The present invention has been completed based on these findings.

[Means for Solving the Problems] That is, the gist of the present invention is an electronic component encapsulation molded product encapsulated with a polyarylene sulfide resin composition,
The interface between the lead frame and/or lead wire of the electronic component and the sealing resin composition has a viscosity before curing of 0.1 to
This electronic component encapsulation molded article is characterized in that it is sealed with an 800 poise (25° C.) dealcoholization type one-component room temperature curing silicone rubber.

Further, according to the present invention, as the PAS resin composition, PA
Melt viscosity (measured at 310°C and shear rate of 104/sec) containing 350-95% by weight and 5-50% by weight of fibrous filler.
A resin composition of 40 to 300 poise can be suitably used. Each component of the present invention will be explained in detail below.

(PAS resin composition) The PAS resin composition used in the present invention uses PAS as a synthetic resin, and includes various fibrous fillers and inorganic fillers to improve physical properties! It is a resin composition containing synthetic resins, elastomers, etc. Among these, those containing fibrous fillers are preferred in order to improve soldering heat resistance. Moreover, in order to improve moldability, it is preferable to use a PAS resin composition having a melt viscosity as described below.

PAS The PAS used in the present invention is a polyarylene sulfide containing 70% by weight or more, more preferably 90% by weight or more of repeating p-phenylene sulfide as the main structural unit of the polymer, and is substantially linear. It is preferable to have a structure like that.

A substantially linear structure is not a polymer having a crosslinked or branched structure such as that obtained by curing to increase the melt viscosity by oxidative crosslinking, but a polymer made essentially from monomers mainly consisting of difunctional monomers. This is the obtained polymer.

Corresponding to the 50% by weight or more of p-phenylene sulfide units, the PAS may also contain 50% by weight of other copolymerized units. Examples of such structural units include m-phenylene sulfide units, diphenylsulfone sulfide units, diphenyl sulfide units, diphenyl ether sulfide units, and 2,6-naphthalene sulfide units. Also preferably used is a block copolymer consisting of 70 to 95% by weight of p-phenylene sulfide repeating units and 5 to 30% by weight of m-phenylene sulfide repeating units.

The PAS used in the present invention is preferably a polymer having a melt viscosity (measured at 310°C and a shear rate of 104/sec) of preferably 10 to 150 poise, more preferably 20 to 130 poise. If the melt viscosity is too low, the resulting molded product will have low mechanical strength, while if it is too high, the fluidity will deteriorate and molding will become difficult, so both are not preferred.

Such PAS can be manufactured by a known method. For example, as described in JP-A-61-7332, an alkali metal sulfide and a dihaloaromatic compound are heated in a specific two-step heating process in the presence of water in an organic amide solvent such as N-methylpyrrolidone. It can be suitably obtained by a polymerization method. It is preferable that the PAS used in the present invention has a substantially linear structure from the viewpoint of processability and physical properties. PA with structure introduced
S can also be used.

In order to improve the solder heat resistance, a fibrous filler is added,
It is preferable to impart flexibility to the resin composition.

As the fibrous filler, for example, fibers or whiskers of glass, potassium titanate, alumina, zirconia, silica, potassium silicate, calcium sulfate, aramid, etc. can be used. Among these, glass fiber in particular has physical properties,
Preferable from an economic point of view.

The fiber diameter is usually 1.1 to 12 μm, preferably 1.1 μm to 12 μm.
A suitable thickness is 1 to 10 μm. If the fiber diameter is too large, there is a risk of element displacement or wire deformation;
If it is too small, it is not preferable because it may stick to the screw or cylinder of the molding machine during sealing molding, making molding difficult.

These fibrous fillers can be used alone or in combination of two or more.

As the PAS resin composition for sealing used in the present invention, PAS
The melt viscosity of the resin composition (310°C, shear rate 1
04/sec) 40 to 300 poise, preferably 60
~250 poise resin compositions are preferred.

If the content of the fibrous filler exceeds 50% by weight, the melt viscosity of the resin composition increases, and if the melt viscosity exceeds 300 poise, element displacement, wire dislocation, deformation, etc. are likely to occur, which is not preferred.

On the other hand, if it is less than 5%, the flexibility will be insufficient, the effect of improving soldering heat resistance will be small, and the exterior will be easily cracked (and the bending strength at room temperature will decrease, leading to the risk of breakage during the terminal bending process). I don't like it because there is. Furthermore, if the melt viscosity is less than 40 voices, it is not preferable because there is a risk of poor appearance due to the occurrence of flakes during molding.

In addition to PAS and fibrous fillers, the PAS resin composition for sealing used in the present invention may optionally contain the following inorganic fillers, other synthetic resins, elastomers, heat-resistant oils such as silicone oil, and pigments. , and other various additives may be added within a range that does not impair the purpose of the present invention.

Inorganic fillers that can be used in the present invention include, for example, curk, mairiki, kaolin, clay, magnesium phosphate,
Magnesium carbonate, calcium carbonate, calcium silicate, calcium sulfate, silicon oxide, aluminum oxide, magnesium oxide, titanium oxide, chromium oxide, iron oxide,
Particulate, scaly, or powdery fillers such as copper oxide, zinc oxide, boron fluoride, and molybdenum disulfide may be used.

These inorganic fillers can also be used alone or in combination of two or more.

A and elastomer - The sealing resin composition of the present invention includes other synthetic resins and elastomers such as polyolefin, polyester, polyamide, polyimide, polyetherimide,
Polycarbonate, polyphenylene ether, boris sulfone, polyether sulfone, polyether ether ketone, polyketone sulfide, polyarylene, polyacetal, polytetrafluoroethylene, borifluoroethylene, polystyrene, ABS resin, epoxy resin, silicone resin, phenol resin , synthetic resins such as urethane resin, or elastomers such as polyolefin rubber, fluororubber, silicone rubber, etc. can be used. These synthetic resins and elastomers can be used alone or in combination of two or more.

The method of mixing each component here is not particularly limited. A commonly used method may be employed, such as a method in which each component is mixed in a mixer such as a tumbler or blender, and then melt-kneaded using an extruder or the like. Also, P.A.
The method for sealing and molding electronic components using the S resin composition is not limited to any particular method. For example, a normal molding method such as an injection molding method can be employed.

(Sealing material) In the present invention, the resin component of the exterior portion and The most distinctive feature is the use of a specific room temperature curable silicone rubber (hereinafter abbreviated as rRTV silicone rubber) that exhibits excellent adhesion to the metal.

Many types of RTV silicone rubber are known, including deacetic acid condensation reaction type, oxime decondensation reaction type, alcohol dealcoding condensation reaction type, and deamine condensation reaction type, but in general, they are characterized by poor workability, moisture resistance, and non-condensation. In terms of performance such as corrosion resistance, for example, Toray Silicone SE9 1 55 to SE9158RTV manufactured by Toray Silicone Company.
and SE9166 to SE9168RTV, and many of the so-called dealcoholization (condensation reaction) type silicone rubbers produced by a dealcoholization condensation reaction between silanol and alkoxysiloxane are used.

In addition to the above, examples of this dealcoholization type one-component RTV silicone rubber include 1.
SE9 100 series manufactured by Shin-Etsu Chemical, K manufactured by Shin-Etsu Chemical
E48, etc., and TSE380 manufactured by Toshiba Silicone
Many types are commercially available, including a fluid type that is a liquid before the curing reaction and a non-flow type that is a solid.

The RTV silicone rubber used in the present invention is one-component type of dealcoholization type, and has a viscosity (at 25° C.) of 0.000. 1~800 poise,
Preferably, the viscosity is from 1 to 600 poise, and in particular, those having a viscosity within this range have an excellent sealing effect on molded electronic parts sealed with the PAS resin composition.

If the viscosity is less than 0.1 poise, the one-component RTV silicone rubber used as a sealant will diffuse too widely from the interface with the lead frame, etc., resulting in poor sealing efficiency. : It becomes difficult to obtain a coating film of the thickness necessary for sufficient performance.

On the other hand, when the viscosity exceeds 800 voices, the fluidity of the one-component RTV silicone rubber decreases, and it becomes insufficient to penetrate into the fine parts at the interface with the lead frame, etc., and the coating film thickness becomes uneven. Moisture resistance is reduced and coating workability is also impaired.

As an RTV silicone rubber sealing material that satisfies these properties, SE9 156 manufactured by Toray Silicone Co., Ltd.
RTV, SE9 1 57LRTV and SE9 1
66RTV etc. can be particularly preferably used. These dealcoholized one-component RTV silicone rubbers have no risk of corroding metals, have excellent stability of electrical properties over time (sealing effect), and are easy to handle because the condensation product is alcohol. is also excellent.

Next, the sealing method using these dealcoholized one-component RTV silicone rubbers is not limited to a specific method. It can be applied by dropping, brushing, or dipping into a one-component RTV silicone rubber solution.

Dealcoholization type one-component RTV silicone rubber is usually cured at room temperature or at a temperature of several tens of degrees Celsius for several hours to one hour.
You can leave it for about a day.

(Electronic component encapsulation molded product) The electronic component encapsulation molded product of the present invention is a one-component RT type in which the interface between the PAS resin composition that is the encapsulation resin composition and the lead frame of the electronic component is dealcoholization type. Filled and sealed with silicone rubber, the sealed electronic components are mechanically protected and have excellent electrical insulation as well as moisture resistance and soldering heat resistance. (The following is a blank space) [Example J The present invention will be specifically described below with reference to Examples, Comparative Examples, and Synthesis Experiment Examples, but the present invention is not limited to these Examples.

[Kukyuu Danshi] (Synthesis of poly p-phenylene sulfide) 373 kg of hydrated sodium sulfide (water content 51.97% by weight) and 1070 kg of N-methylpyrrolidone (hereinafter abbreviated as "NMPJ")
kg into a titanium-lined autoclave and heated to approximately 203℃.
A small amount of NMP and H. Water containing S was distilled out.

Next, 347 kg of p-dichlorobenzene was charged.

After reacting at 220° C. for 5 hours, 77 kg of water was added. Then, polymerization was carried out at 258°C for 3 hours. The reaction mixture was sieved through a screen with an opening of 0.1 mm to separate the polymer, which was then washed with acetone and water to obtain a washed polymer.

This washed polymer was immersed in a 2% N84C1 aqueous solution,
After processing at 40°C for 30 minutes, it was washed with water, and vacuumed at 80°C to prepare poly p-phenylene sulfide (hereinafter referred to as rP P
PSJ) was obtained. The melt viscosity of this PPPS (3
The shear rate (1047 seconds) at 10° C. was 100 poise.

[Example 1] 90% by weight of PPPS obtained in the synthesis experiment example and glass fiber (ECSO3T-7 1 7DE/P manufactured by Nippon Electric Glass Co., Ltd.)
10% by weight was uniformly dry-blended using a blender and pelletized using a twin-screw kneading extruder at a cylinder temperature of 310°C. Melt viscosity was measured using this pellet.

In addition, test beads (shape 130xl2.7
X3.2mm) was created.

Furthermore, using this pellet, a capacitor (capacitance 1
0 0 n F) is sealed, and a dealcoholized one-component RTV silicone rubber (manufactured by Toray Silicone SE9 1) is placed between the resin composition of the sealed molded product and the lead.
57LRTV).

After dropping, the RTV silicone rubber was cured by being left at 20° C. and 50% humidity for 20 hours.

Evaluation tests were conducted on the obtained sealed electronic components using the following method.

11L Next Work'' Element displacement, etc.> In order to determine whether the capacitor element is properly sealed, that is, whether there is any element displacement or peeling of the lead wire, a soft X-ray transmission method is used. Observations were made by The presence or absence of element displacement etc. was evaluated in the following two stages.

○: None, ×: Yes (Moisture resistance) Moisture resistance was determined by conducting a bias test (85°C 95% DC-25V), and it was measured whether all capacitance changes after 500 hours were within 5%. Evaluation was performed in the following two stages.

○: Capacitance change value is within 5%, ×: Soldering heat resistance exceeds 5% Soldering heat resistance is determined by measuring 5 of the sealed electronic components judged to be normal by observation using soft X-ray transmission method. High temperature and humidity chamber (85℃, 8
5%) for 4 hours, immersed in a solder bath at 260° C. for 10 seconds, and cracks on the exterior were determined visually and using a microscope. Evaluation was performed in the following two stages.

○: No cracks, X: With cracks The measurement results are shown in Table 1.

[Example 2] Test beads and sealed electronic components were molded and evaluated in the same manner as in Example 1, except that 70% by weight of PPPS and 30% by weight of glass fiber were uniformly dry blended using a blender. .

[Example 3] 360% by weight of PPP, 30% by weight of glass fiber, and potassium titanate fiber (HT-200 manufactured by Nippon Titanium Industry Co., Ltd.)
Test beads and sealed electronic components were molded and evaluated in the same manner as in Example 1, except that 10% by weight was uniformly dry blended using a blender.

[Example 4] RTV silicone rubber (manufactured by Toray Silicone ■ SE9 1) was placed between the resin composition of the encapsulation molded product and the lead wire.
Test beads and electronic components were encapsulated and molded in the same manner as in Example 1, except that 56RTV) was applied, and evaluated in the same manner.

[Example 5] RTV silicone rubber (SE9 1 6 manufactured by Toray Silicone Co., Ltd.) was placed between the resin composition of the encapsulation molded product and the lead wire.
Test beads and electronic components were molded and evaluated in the same manner as in Example 1, except that 6RTV) was applied.

[Example 6] 10% by weight of pppsso, 10% by weight of glass fiber (ECSO3T-717DE, manufactured by Nippon Electric Glass Co., Ltd.), and 10% by weight of fused silica (FS-44, silane-treated product, manufactured by Denki Kagaku ■ Co., Ltd.) were uniformly mixed using a blender. [Comparative Example 1] Test beads and electronic components were encapsulated and evaluated in the same manner as in Example 1, except that they were dry blended. [Comparative Example 1] RTV
A test bead and an electronic component were sealed and molded in the same manner as in Example 1, except that the dripping of silicone rubber was stopped, and evaluated in the same manner. [Comparative Example 2] Toray Silicone rubber, which has a high viscosity (25° C.) of 900 voices, was used as an RTV silicone rubber. Cone SE9
Test beads and electronic components were sealed and molded in the same manner as in Example 1, except that 158RTV was used, and evaluated in the same manner.

[Comparative Example 3] 40% by weight of PPPS and 60% by weight of glass fiber were uniformly dry blended using a blender. Test beads and electronic components were encapsulated and molded in the same manner as in Example 1 except for L:J. They were evaluated in the same way.

[Comparative Example 4] Test beads and electronic components were encapsulated and evaluated in the same manner as in Example 1, except that 97% by weight of PPPS and 3% by weight of glass fiber were uniformly dry blended using a blender. .

[Comparative Example 5] R T V silicone rubber used in Example 1 SE-9
Dilute 157LRTV with carbon tetrachloride to reduce the viscosity to 0.0.
Electronic components were sealed and molded in the same manner as in Example 1 except that the temperature was adjusted to 5 voices (25° C.) and evaluated in the same manner.

The results of Examples 1 to 6 and Comparative Examples 1 to 4 were combined into the first
Shown in the table.

(The following is a blank space) [Effects of the Invention] In the electronic component encapsulation molded product of the present invention, the interface between the encapsulation PAS resin composition and the lead frame of the electronic component is sealed with a dealcoholized one-component RTV silicone rubber. As a result, moisture resistance, soldering heat resistance, etc. are improved compared to conventional products.

Claims (2)

[Claims] (1) An electronic component encapsulation molded product encapsulated with a polyarylene sulfide resin composition, wherein the interface between the lead frame and/or lead wire of the electronic component and the encapsulation resin composition has a viscosity of 0 before curing. .1~800 poise (25℃
1.) An electronic component encapsulation molded article, characterized in that it is sealed with a dealcoholization type one-component room temperature curing silicone rubber. (2) The polyarylene sulfide resin composition contains 50 to 95% by weight of polyarylene sulfide and 5% by weight of fibrous filler.
Melt viscosity containing ~50% by weight (310°C, shear rate 10
The electronic component encapsulation molded article according to claim 1, which is a resin composition having a poise of 40 to 300 poise (measured at ^4/sec).