JPS6155148A - Composition for sealing electronic part and use thereof - Google Patents

Abstract

PURPOSE:To provide a resin compsn. for sealing electronic parts, which has excellent moisture resistance, by using a specified phenylene sulfide block copolymer as a resin component. CONSTITUTION:A phenylene sulfide block copolymer [melt viscosity (at 310 deg.C, shear rate of 200/sec): 10-1,500P] composed of repeating units of formulas I and IIwherein its molecular chain contains the repeating unit of formula I as a block having an average MW of 200-2,000 in a molar fraction of 0.5-0.95 is used. 20-300pts.wt. inorg. filler (e.g. glass fiber having a length of 0.5mm. or below or alumina powder having a particle size of 0.5mm.) is mixed with 100pts.wt. phenylene sulfide block copolymer.

Description

BACKGROUND OF THE INVENTION TECHNICAL FIELD The present invention relates to a composition for encapsulating electronic components and its use. More specifically, the present invention relates to a composition for encapsulating electronic components whose main feature is a resin component and its use.

11c,) Electronic components such as transistors, diodes, and capacitors are sealed with synthetic resins, ceramics, etc. for the purpose of preventing changes in characteristics due to external atmosphere, preventing deformation, and maintaining electrical insulation.

Conventionally, thermosetting resins, especially epoxy resins, silicone resins, etc., have been used for resin sealing. This method has disadvantages such as requiring a large amount of blow-down air, dirt from the mold accumulates as the number of molded shots increases, the resin tends to deteriorate during storage, and unnecessary molded parts cannot be reused.

Prior art As a method to solve these drawbacks, thermoplastic mR&
(1) Ho! A method using 7-p-phenylene sulfitora has been published (Japanese Patent Publication No. 56-2790, JP-A No. 53-22363, JP-A-56-81957, JP-A-59-20910, 59-20911, etc.).

However, in the case of poly-p-phenylene sulfide, sealing is usually performed by melt molding, but in that case, crystallization progresses rapidly while producing coarse spherulites when changing from a molten state to a solidified state. , the resin layer, especially around the spherulite part,
Large molding shrinkage occurs, causing cracks in the resin layer, cutting and deforming the bonding wire, and +7
- A gap is likely to be formed at the bonding surface between the bonding frame or the bonding wire and the resin layer. Therefore, the obtained electronic component has a problem in that moisture enters from the interface of the lead frame or the bonding wire, particularly in a high-temperature, high-humidity atmosphere, and the quality of the electronic component is likely to deteriorate. In order to solve this problem, attempts have been made to add inorganic fillers and various auxiliary agents, but no essential solution has been achieved unless the properties of the basic resin are changed.

Summary of the Invention The present invention solves these problems by using a phenylene sulfide block copolymer as the main resin component, and provides a composition for encapsulating electronic components with excellent moisture resistance.

Therefore, the composition for encapsulating electronic components according to the present invention is composed of a synthetic resin component 1001 and 20 to 300 parts by weight of an inorganic filler, and the synthetic resin component is mainly composed of the following phenylene sulfide block copolymer. It is characterized by:

A phenylene sulfide block copolymer whose molar content is in the range of 0.50 to 0.95 and whose melt viscosity is 10 to 1500 poise (310° C., Separation A, R speed 200 (e)-'). .

Furthermore, the method for encapsulating electronic components according to the present invention comprises 100 parts by weight of a synthetic resin component and 20 to 300 parts by weight of an inorganic filler, and the synthetic resin component mainly consists of the following 7-enylene sulfide block copolymer. The present invention is characterized in that an electronic component is sealed by an injection molding method using the composition as a sealing composition.

The repeating unit ÷ S ÷ is the repeating unit e8j, the molar fraction thereof is in the range of 0.50 to 0.95, and the melt viscosity is 10 to 1500 voids [310 ° C., shear p degree 200
($)-” ) phenylene sulfide block copolymer.

Effects The phenylene sulfide block copolymer used as the base resin in the present invention substantially enjoys the attributes of a phenylene sulfide homopolymer as a crystalline polymer, while solving the aforementioned problems observed in the polymer. , electronic components can be sealed well.

The synthetic resin component, which is one component of the composition of the present invention, is mainly composed of a phenylene sulfide block polymer.

For the phenylene sulfide block cohomer, repeating units D-B→ and repeating units - are used. The presence of the Puff-s+ block ensures the crystallinity of the copolymer and the resulting heat resistance.

In addition, the presence of the repeating unit fQ-8-5- significantly improves the injection moldability by lowering the melt viscosity of the copolymer, and also prevents the formation of cracks by preventing the formation of coarse spherulites. By preventing cutting or deformation of the lead frame or bonding wire, and improving the adhesion to the lead frame or bonding wire, the high temperature and humidity resistance of the sealed electronic component can be greatly improved.

The introduction of this repeating unit f()-sf solves the drawbacks of the arphenylene sulfide homopolymer.

This repeating unit fo-87 contains a small amount of other ÷Ar-8
There is no problem even if thousands are included randomly. Here, mul means a residue of an aromatic compound. For such ÷mu r-8+, one or more of the following groups are preferably used.

PeyO (Σ day ÷ Ben Q-B ÷, the average degree of polymerization of the block copolymer of the present invention ÷ o-6 ÷ blocks is in the range of 20 to 2000, preferably 40 to 1000) .The average degree of polymerization is 2
If it is less than 0, the crystallinity of the polymer will be insufficient and there is a risk of giving a molded product with insufficient heat resistance.
If the molecular weight is too large, the properties may become close to those of p-phenylene sulfide homopolymer, which may result in molded products with broken bonding wires containing cracks or molded products with poor high temperature and humidity resistance, so either is preferable. do not have.

÷O-s÷÷5s÷ belonging to the block The basic mole fraction of the repeating unit is in the range of 0.50 to 0.95, particularly preferably in the range of 0.60 to 0.90. If the basic molar fraction is less than 0.5, the crystallinity of the resin may be insufficient and a molded product with insufficient heat resistance may be obtained;
If the number exceeds 5, the properties become close to those of p-phenylene sulfide homopolymer, which may result in a molded product having poor high temperature and humidity resistance, so any of these is not preferred. In addition, the mole fraction can be easily confirmed by IFT/1-unit analysis.

In addition, the average sea fence length of the -s+ block can be measured by fluorescent X-ray method.

A phenylene sulfide block copolymer with such a chemical structure usually has a To (glass transition point) −
20~80℃, Tm (crystal melting point) -250~285℃
, Crystallization index of heat treated product (not stretched orientated) 01-
It has properties of s5-45. By the way, p-phenylene sulfide homopolymer &t TO-85~95℃
, Tm is in the range of -280 to 295°C, C11 = 35 to 50, and TQ is particularly high. On the other hand, ÷ SS year unit? S-te unit? The random copolymers are amorphous (i.e. Ol; O)
and has no Tm. In addition, here, the crystallization index 01 is obtained by separating the crystalline scattering intensity Ac and the amorphous scattering intensity Mua at 20-17-23° from the X'a diffraction pattern, and is 0.
1=(Muc/(Ac+Aa):) x This is the value calculated from the 1000 formula (J, MuI)1) 1. POly,
(See Sai, Takeshi, 2545 (1976)). In addition, the value of 01 of the present invention is determined by hot pressing the polymer at a temperature approximately 30°C higher than Tm and quenching it with water to a value of 0.1 to 0.2 mm.
Prepare a film with a thickness of 1 to 20°C.
This value is for a heat-treated product that was heat-treated at a low temperature for 20 minutes and crystallized.

The molecular weight of the phenylene sulfide block copolymer of the present invention is suitably in the range of 10 to 1500 voids (310°C/shear rate -200 (Company)), particularly preferably in the range of 30 to 800 voids, as an indicator of melt viscosity. . If it is less than 10 voids, the molecular weight is too small and there is a risk of giving a molded product with insufficient strength, and if it exceeds 1,500 voids, the melt viscosity is too high and may cause the bonding wire to break during injection molding or poor filling. Both are undesirable as they may cause

A phenylene sulfide block copolymer having the above-mentioned properties can be produced, for example, by polycondensation of an alkali sulfide and a dihaloaromatic compound in an aprotic organic solvent through a dehalogenation/sulfurization reaction (Japanese Patent Application No. 1983).
9-134833).

In addition to the main component nophenylene sulfide block copolymer, the resin component of the sealing composition of the present invention includes a small amount of other thermoplastic resins (poly-m-phenylene sulfide, poly-m-phenylene sulfide, Poly-two phenylene sulfide, m-phenylene sulfide-p-7 ene nylene sulfide random copolymer, polybutylene terephthalate, polyethylene terephthalate, polyether fulfone, polyamide, etc.) or thermosetting resin (
It is also possible to use a mixture of epoxy resin, silicone resin, urethane resin, etc.).

Among the resin components, the main component is phenylene sulfide block.
m-phenylene sulfide (haboIJ-p-phenylene sulfide is preferred).

Filler In the sealing composition of the present invention, the inorganic filler includes:
Fibrous fillers or non-fibrous fillers or both can be used.

Non-fibrous fillers include quartz powder, glass powder, glass beads, alumina powder, Tie powder, iron oxide powder,
Talc, clay, mica, etc. can be used. Particle size is 0.
It is preferably 5 mm or less. If it exceeds 0.5 mm, the bonding wire may be cut, which is not preferable.

As the fibrous filler, glass fiber, silica fiber, wollastonite, potassium titanate fiber, processed mineral fiber, ceramic fiber, etc. can be used, and it is preferable that the fiber length is Q, 5 mm or less and the aspect ratio is 10 or more. . 0, 5
If the aspect ratio exceeds mm, the bonding wire may be cut, and if the aspect ratio is less than 10, the reinforcing effect may be insufficient, and both are unfavorable.

When an inorganic filler is mixed into the sealing composition of the present invention, the amount of the inorganic filler mixed is preferably 20 to 300% by weight, particularly 500% by weight.
0-200 weight class is good weight. If the amount exceeds 300% by weight, the melt viscosity of the composition becomes high, which may cause the bonding wire to break, which is not preferable. Also, 2
If it is less than 0 qb, the coefficient of thermal expansion becomes too large and there is a risk of cutting the bonding wire, which is not preferable.

When an inorganic filler is mixed into the encapsulating composition of the present invention, the inorganic filler is added in order to improve the adhesion between the inorganic filler and the resin or to reduce the hygroscopicity of the inorganic filler. , using a surface treatment agent such as a silane coupling agent or a titanate coupling agent to make it hydrophobic.
Alternatively, these reagents can also be used by adding them to the sealing composition. Furthermore, in order to further improve the moisture resistance of the sealing composition, a water repellent such as modified silicone oil, fluorine oil, paraffin, or the like can be added to the composition. In addition, auxiliary agents such as lubricants, colorants, mold release agents, heat stabilizers, and curing agents may be added to the sealing composition of the present invention without departing from the purpose of the present invention.

After the synthetic resin component for sealing electronic parts, the inorganic filler, and other auxiliary agents as needed are mixed, the composition is used to seal the electronic parts.

The sealing method can be performed by a generally known method, for example, a molding method using injection molding or transfer molding. That is, using a normal injection molding machine or transfer molding machine, the molding pressure is 10 to 200.
J/Qm", cylinder temperature 280~370'C
, and the mold temperature is preferably in the range of 80 to 220°C.

The sealing method that best takes advantage of the feature of the present invention, in which the resin component is a block copolymer with improved crystallization properties, is a method in which sealing is performed by injection molding of the resin composition.

Experimental Example Synthesis Example (1) 11.0 kg of NMP (N-methylpyrrolidone) and Na2S were placed in a 20 liter pressure-resistant polymerization can.
5H2020-0% L was charged and the temperature was raised to about 200°C, during which water and some NMP were accumulated (the amount of water remaining in the polymerization reactor was 26 moles). Then, NMP3-OkgK'p-dichlorobenzene2
A solution containing 0.1 mol dissolved therein was charged and heated at 215° C. for 3 hours. Then, add 54 mol of water and heat to 255°C.
The mixture was heated for 0.5 hour to obtain a reaction mixture a. This was taken out of the can and stored. A small amount of this liquid a was sampled, and the average degree of polymerization of the produced p-phenylene sulfide prepolymer was measured by fluorescent X-ray method. Degree of polymerization -190
Met.

Charge 2.2 kg of NMP and Na, S, 5H204-0 mo) 1- into a 201 J liter pressure-resistant polymerization can, and
Heat to 0"C, and remove moisture and some N during that time.
MP was stored (residual water content in the polymerization reactor was 5.5 moles). Sokohe, NMP O* 6 kg m-
A solution containing 4.0 moles of dichlorobenzene was charged and mixed. To this mixed solution, 80% of the total amount of the reaction mixture a that had already been stored and 21.0 mol of water were added and mixed, and the mixture was heated at 255° C. for 2 hours to react. After the reaction,
The reaction solution was diluted approximately twice with NMP and filtered to remove the solid content.
It was separated, washed four times with hot water, dried under reduced pressure at 80°C, and the composition was analyzed using p-phenylene sulfide FT-IR to obtain a composition with a melt viscosity of η'' [31
0°C, shear rate -200 "1" was 690 voids. Also, TO -73°C, Tm -278°C, 260
The C1 value of the product heat-treated for 1 min was 33.

Note that TO and Tm were measured using a differential scanning calorimeter.

(2) A reaction mixture 111 was prepared and stored in the same manner as in (1). The average degree of polymerization of the p-phenylene sulfide prepolymer produced in this 111 liquid was 170.

A 10 liter pressure-resistant polymerization can was charged with 2.2 kg of NMP and 4.0 mol of Na2S, 5H20, and the temperature was raised to approximately 200°C, during which water and Wakasen ONMP were accumulated (residual water content in the polymerization can). was 5.2 mol). A solution containing 0.7 kg of NMI' and 4.1 mol of m-dichlorobenzene was charged and mixed. Then, a reaction was carried out by heating at 215°C for 3 hours to prepare a reaction mixture "o2". A small amount of the b2 solution was sampled.
The degree of polymerization of the produced m-phenylene sulfide prepolymer was measured using fluorescent X-rays. The degree of polymerization was 20.

80% of the total amount of the BL solution, the entire amount of the B2 solution, and 20 moles of water were added to a 20 liter pressure-resistant polymerization can, and the mixture was heated and reacted at 255° C. for 4 hours. After the reaction, Tefolimer B (p-) unilene sulfide block copolymer-@)-8+block average degree of polymerization 180) was obtained in the same manner as in (1).

The composition of this polymer B was ruti. Also, Δη”
-580 Boise, 70177℃, Tm -280℃, 0
It was l-35.

(3) JP in a 20 liter pressure-resistant polymerization can 11.
0 kg and Na213-5H! 010.0% of polymer was charged and the temperature was raised to approximately 200°C, during which water and a small amount of NMP were distilled out (the amount of remaining water in the polymerization reactor was 13 moles). kJMP 3.01c
g, m-dichlorobenzene 10.0 mole 1 +
3s 0.10 mol of 5-trichlorobenzene was added and reacted at 210°C for 10 hours, then 47 mol of water was added and reacted by heating at 260°C for 12 hours. After the reaction was completed, Polymer 0 (m-phenylene sulfide homopolymer) was obtained in the same manner as in (1). η" was about 20 poise.

(4) 20 liter pressure can K NMP 11.0
kg and 2020.0 mol of Na 2 B .5H were charged, and the temperature was raised to about 200° C., during which time water and some NMP were accumulated (the amount of remaining water in the polymerization reactor was 26 mol).

NMP there 3. 20.2 moles of Okg, Il-dichlorobenzene and 54 moles of water were added, and the mixture was heated at 260°C for 3 hours to react.゛After the reaction was completed, Polymer D (p-phenylene sulfide homopolymer) was obtained in the same manner as in (1).

It was 1"-610 boise.

Molding Example Various types of phenylene sulfide poly-i-, a predetermined amount of inorganic filler, and a predetermined amount of additive auxiliary agent are mixed uniformly using a Henschel Φcer, and the cylinder is heated to one temperature using a 30Φ co-directional twin-screw extruder. It was extruded and pelletized at 290°C to 330°C. The obtained pellets are molded using an injection molding machine at a cylinder temperature of 300 to 340°C and a metal temperature of 120 to 180°C.
Injection molding was performed using a mold into which a transistor-9 frame was inserted at an injection pressure of 20 to 60 kg/am2.

After boiling each of the obtained sealed products in red ink for 24 hours, cracks in the sealing resin and the state of infiltration of the red ink from the interface between the sealing resin and the frame were observed. The results were as shown in Table 1.

Claims (1)

[Claims] 1. 100 parts by weight of synthetic resin component and 20 to 3 parts by weight of inorganic filler
00 parts by weight, and the synthetic resin component is mainly composed of the following phenylene sulfide block copolymer. Repeating unit ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and Repeating unit ▲ There are mathematical formulas, chemical formulas, tables, etc. It is bonded in the molecular chain with blocks with a degree of polymerization of 0.50 to 0.9.
5, and the melt viscosity is in the range of 10 to 1500 poise [3
A phenylene sulfide block copolymer with a shear rate of 10° C. and a shear rate of 200 (seconds). 2. The composition for encapsulating electronic components according to claim 1, wherein the synthetic resin component consists only of a phenylene sulfide block copolymer. 3. The composition for encapsulating electronic components according to claim 1, wherein the synthetic resin component is a phenylene sulfide block copolymer mixture containing 40% by weight or less of m-phenylene sulfide polymer. 4. The composition for encapsulating electronic components according to claim 1, wherein the synthetic resin component is a phenylene sulfide block copolymer mixture containing 40% by weight or less of p-phenylene sulfide polymer. 5. The inorganic filler is a fibrous filler with a length of 0.5 mm or less or a non-fibrous filler with a particle size of 0.5 mm or less,
A composition for encapsulating electronic components according to any one of claims 1 to 4. 6. 100 parts by weight of synthetic resin component and 20 to 3 parts by weight of inorganic filler
00 parts by weight, and the synthetic resin component is mainly composed of the following phenylene sulfide block copolymer. Method of sealing electronic components. Repeating unit ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and Repeating unit ▲ There are mathematical formulas, chemical formulas, tables, etc. It is bonded in the molecular chain with blocks with a degree of polymerization of 0.50 to 0.9.
5, and the melt viscosity is in the range of 10 to 1500 poise [3
A phenylene sulfide block copolymer with a shear rate of 10° C. and a shear rate of 200 (seconds).