JP3024149B2 - Electronic component sealant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a sealant for an electronic component comprising an aromatic polyester. More specifically, low melt viscosity,
The present invention relates to an electronic component sealant having high toughness, high heat resistance, and excellent moisture resistance.

<Prior art> For electronic components such as ICs, transistors, diodes, and capacitors, ceramics, synthetic resins, etc. are used for the purpose of preventing their characteristics from changing due to an external atmosphere, preventing deformation due to external force, and maintaining electrical insulation. Sealing is performed.

Conventionally, thermosetting resins represented by silicone resins and ortho-cresol novolak type epoxy resins have been used as synthetic resin encapsulants, but these thermosetting resins require a long time for thermosetting and require The time is long, post cure is required, the number of molding shots increases, mold contamination occurs, and the content of hydrolyzable chlorine caused by epichlorohydrin, which is a resin raw material, is large. There are problems such as adverse effects such as corrosion on Al wiring, which constitute electronic components.

As a method for solving such a problem, typical diols such as p-hydroxybenzoic acid and phenylhydroquinone and chlorohydroquinone and terephthalic acid;
Japanese Patent Application Laid-Open No. 60-44521 discloses the use of a liquid crystal polyester composed of a dicarboxylic acid represented by 1,4-cyclohexylenedicarboxylic acid as a sealant for an integrated circuit module.

JP-A-60-40163 discloses that a polyester obtained by copolymerizing 6-hydroxy-2-naphthoic acid, 4-hydroxybenzoic acid and the like and a particulate inorganic material are used for sealing electronic components. I have.

<Problems to be Solved by the Invention> However, the polyester disclosed in Japanese Patent Application Laid-Open No. 60-44521 has a low degree of toughness. There is a problem that the melt viscosity increases, which causes deformation and damage of the wiring material. The glass transition temperature (Tg) is 150 ° C or less, and the heat resistance is low. Was not enough.

Further, the polyester disclosed in JP-A-60-40163 has a problem in adhesiveness to electronic parts and has insufficient moisture resistance. It was not enough because there was a problem.

Therefore, an object of the present invention is to obtain an electronic component sealant having a low melt viscosity, a high toughness, and excellent heat resistance and moisture resistance.

<Means for Solving the Problems> The present inventors have made intensive studies to solve the above problems, and as a result, have reached the present invention.

That is, the present invention provides the following structural units (I) to (III)
And the structural unit (I) is composed of the structural units (I) and (I
40 to 80 mol% based on the total of the structural units (II), and 60 to 20 mol% based on the total of the structural units (I) and (II)
The present invention provides an electronic component sealing agent containing an aromatic polyester in which the structural unit (III) is substantially equimolar to the structural unit (II).

O-Ar in _{1 -O ... (II) OC-} Ar 2 -CO ... (III) ( the above formula, Ar ₁ is Ar ₂ represents two or more groups selected from It represents one or more groups selected from, Ar ₁ is And Ar ₂ is Except when.

(2) The electronic component sealing agent according to the above (1), further comprising an inorganic filler in an amount of 20 to 80% by weight based on the whole, and (3) the electronic component according to the above (1) or (2). It is a sealed electronic component sealed with a sealing agent.

The structural unit (I) is a structural unit generated from p-hydroxybenzoic acid. Further, the structural unit (II) includes hydroquinone, 4,4'-dihydroxybiphenyl and
Structural units formed from two or more aromatic dihydroxy compounds selected from 2,6-dihydroxynaphthalene, and the structural unit (III) is at least one aromatic compound selected from terephthalic acid and 2,6-naphthalenedicarboxylic acid. The structural units formed from the dicarboxylic acid of the aromatic group are shown.

Among them, those having a structural unit formed from 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene as the structural unit (II) and a structural unit formed from terephthalic acid as the structural unit (III) are particularly preferable.

The structural unit (I) is 40 to 80 mol%, preferably 60 to 80 mol%, based on the total of the structural units (I) and (II). Further, the structural unit (II) is 60 to 20 mol%, preferably 40 to 20 mol%, based on the total of the structural units (I) and (II). When the structural unit (I) exceeds 80 mol% or less than 40 mol% with respect to the total of the structural units (I) and (II), the obtained polymer has a high melt viscosity and is a sealing agent for electronic parts. Not suitable for use as

The structural unit (II) is a structural unit formed from two or more aromatic dihydroxy compounds selected from hydroquinone, 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene. In the case where the structural unit (II) is a structural unit formed from a single compound, the melt viscosity is high, which is not suitable for the purpose of the present invention. Further, among the above three kinds of aromatic dihydroxy compounds, a structural unit generated from one kind of the compound is 80 mol% of the whole structural unit (II).
Preferably it does not account for more, more preferably not more than 75 mol%.

Further, regarding the structural unit (III), the structural unit (II)
And are substantially equimolar.

In the polycondensation of the aromatic polyester used for the electronic component sealing agent of the present invention, the above structural units (I) to (II)
In addition to the components constituting I), aromatic compounds such as isophthalic acid, 4,4'-diphenyldicarboxylic acid, 3,3'-diphenyldicarboxylic acid, 3,4'-diphenyldicarboxylic acid, and 2,2'-diphenyldicarboxylic acid Aliphatic dicarboxylic acids such as aliphatic dicarboxylic acids, alicyclic dicarboxylic acids such as hexahydrophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecandioic acid, 2,2-bis (4-hydroxyphenyl) propane, bis ( Aromatic dihydroxy compounds such as 4-hydroxyphenyl) sulfone, and aliphatics such as 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, ethylene glycol, diethylene glycol, polyethylene glycol, and 1,4-cyclohexanedimethanol , Alicyclic diol, m-hydroxybenzoic acid, 6-hydroxy-2-naphthoe Aromatic hydroxycarboxylic acids such as acids, p-aminobenzoic acid, p-aminophenol, and the like can be further copolymerized in a small proportion that does not impair the object of the present invention.

The aromatic polyester used in the encapsulant for electronic parts of the present invention can be produced according to a conventional polyester polycondensation method, and the production method is not particularly limited. A typical production method is, for example, p-hydroxybenzoic acid. A method of acetylating a phenolic hydroxyl group from an aromatic dihydroxy compound such as 4,4′-dihydroxyphenyl and an aromatic dicarboxylic acid such as terephthalic acid and acetic anhydride, followed by a method of producing the compound by a deacetic acid polycondensation reaction, Structural unit (II)
When a structural unit formed from 2,6-dihydroxynaphthalene is used, it is preferable to use 2,6-diacetoxynaphthalene instead of using 2,6-dihydroxynaphthalene.

Polymerization catalysts can be used for these polycondensation reactions.However, as a sealant for electronic components, ionic substances such as Na ⁺ and K ⁺ that may promote corrosion of Al wiring etc. are used. Since it is preferable not to be added to the system, Na,
It is preferable not to use a catalyst containing K or the like.

The aromatic polyester used for the electronic component sealing agent of the present invention has a thermotropic liquid crystal property that exhibits optical anisotropy in a molten state.

Further, the melt viscosity of the aromatic polyester used in the sealant for electronic parts of the present invention is preferably 10 to 5,000 poise, particularly 1
0-3,000 poise is preferred.

The melt viscosity is a value measured by a Koka flow tester at a temperature of (liquid crystal onset temperature + 40 ° C.) at a shear rate of 200 (1 / second).

The thus obtained electronic component sealing agent of the present invention has a low melt viscosity, can be injection-molded at a low pressure, and can be used for sealing ICs, transistors, diodes, capacitors, and the like.

In addition, it is possible to mix | blend an inorganic filler with the electronic component sealing agent of this invention, and it is more preferable to mix | blend. Specific examples of the filler include glass fiber, glass beads, silicon oxide, metal oxides such as aluminum oxide, silicon nitride, metal nitrides such as boron nitride, among which fused silica and crystalline silica are preferable. Particularly, fused silica is preferable. As particularly preferred fused silica, those having shapes such as crushed silica and spherical silica can be used, and spherical silica can be more preferably used from the viewpoint of fluidity. For granular or spherical inorganic fillers,
Those having an average particle diameter of 70 μm or less are preferred.

The addition amount of these inorganic fillers is based on the entire composition.
20-80% by weight is preferred.

Further, the surface of these inorganic fillers can be treated with a known surface treatment agent before use. Examples of the surface treatment agent include a silane compound, a titanate compound, and an epoxy compound.

Further, for the electronic component sealing agent of the present invention, a nucleating agent, a pigment,
Additives such as antioxidants, stabilizers, plasticizers, lubricants, release agents and flame retardants and other thermoplastic resins can be added to impart desired properties to the molded article.

A practical sealed electronic component can be obtained by sealing an electronic component such as a semiconductor chip using the electronic component sealing agent of the present invention.

<Example> Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 884 g (6.4 mol) of p-hydroxybenzoic acid, 179 g (0.96 mol) of 4,4'-dihydroxybiphenyl, 156 g (0.64 mol) of 2,6-diacetoxynaphthalene, 266 g of terephthalic acid
(1.6 mol) and 934 g (9.15 mol) of acetic anhydride were charged into a reaction vessel equipped with a stirrer and a distillation tube, and subjected to deacetic acid polymerization under the following conditions.

First, under nitrogen atmosphere, 100 ~ 250 ℃ for 5 hours, 250 ~ 3
After reacting at 40 ° C. for 2 hours, the pressure was reduced to 1 mmHg at 340 ° C. for 1.5 hours, and the reaction was further performed for 1 hour to complete the polycondensation. I got

k // m / n = 80/12/8/20 The polyester was placed on the sample stage of a polarizing microscope, and the temperature was raised to confirm the optical anisotropy. It showed anisotropy. The melt viscosity measured at 327 ° C. was 520 poise (shear rate 200 (1 / second)).

60% by weight of this resin and 40% by weight of fused silica (spherical having an average particle diameter of 20 μm) were extruded at 320 ° C. by an extruder.

This composition was supplied to an injection molding machine exclusively for inserts, and sealing molding of a semiconductor element was performed. As the semiconductor element, a semiconductor chip was used in which a semiconductor chip was mounted on a support frame of ten stations and electrodes of the semiconductor chip were connected to terminals of the support frame by aluminum wiring. As the molding pressure, the lowest pressure at which the resin was completely filled in the mold was selected.

The obtained sealed sample was subjected to a moisture resistance test at 121 ° C. under a pressure of 2 atmospheres of water vapor for 100 hours.
It was 10 ^-3 μA on average when measured for 0 sealed parts.

In addition, the heat cycle test of the sealed sample was -55.
℃, +155 ℃, 30 minutes each, 1,000 cycles,
The crack occurrence rate was 2%, and the defect (disconnection) occurrence rate was 3%.

Example 2 In the same reaction vessel as in Example 1, p-hydroxybenzoic acid 829 g (6.0 mol), 4,4'-dihydroxybiphenyl 24
9 g (1.34 mol), hydroquinone 72.7 g (0.66 mol),
432 g (2.0 mol) of naphthalenedicarboxylic acid and 1123 g (11.0 mol) of acetic anhydride were charged, and deacetic acid polymerization was carried out under the same conditions as in Example 1. As a result, a resin having the following theoretical structural formula was obtained.

k // m / n = 75 / 16.7 / 8.3 / 25 The liquid crystal onset temperature of the obtained polymer was 300 ° C., and the melt viscosity measured at 340 ° C. was 310 poise (shear rate 20
0 (1 / second)).

This polymer was blended with fused silica at the same composition ratio as in Example 1 to obtain a composition.

This polymer was used as a sealing agent in the same manner as in Example 1, and a moisture resistance test was performed under the same conditions.
It was found to be as low as ^-3 μA.

As a result of the heat cycle, good results were obtained with a crack occurrence rate of 2% and a defective rate of 4%.

Comparative Example 1 p-hydroxybenzoic acid 829 g (6 mol), 2,6-diacetoxynaphthalene 488 g (2 mol), terephthalic acid 332 g
Example 2 (2 mol) and 674 g (6.6 mol) of acetic anhydride
And a resin having the following theoretical structural formula was obtained.

k // m = 75/25/25 The liquid crystal onset temperature of the obtained polymer was 285 ° C, the melt viscosity was 325 ° C, and the shear rate was 200 (1 / sec).
It had a high viscosity of 400 poise.

This polymer was blended with fused silica at the same composition ratio as in Example 1 to obtain a composition.

This composition was applied to a molding machine exclusively for inserts in the same manner as in Example 1 to perform encapsulation molding of a semiconductor element. The resulting leakage current value was subjected to moisture resistance test samples under the conditions of Example 1 had a mean 10 ² .mu.A. As a result of the heat cycle test, the crack occurrence rate was 9%, and the defect (disconnection) occurrence rate was 24.
%Met.

<Effects of the Invention> According to the present invention, an electronic component encapsulant having low melt viscosity, high toughness, excellent moisture resistance and durability, and high heat resistance can be obtained.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI H01L 23/31 (58) Investigated field (Int.Cl. ⁷ , DB name) C08G 63/00-63/91 C08L 67/00 -67/08 H01L 23/28-23/30 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. It comprises the following structural units (I) to (III):
Structural unit (I) is 40 to 80 mol% based on the total of structural units (I) and (II), and structural unit (II) is structural unit (I)
And (II) in an amount of 60 to 20 mol%, wherein the structural unit (III) is substantially equimolar to the structural unit (II). O—Ar ₁ —O (II) CO—Ar ₂ —CO (III) (where Ar ₁ is Ar ₂ represents two or more groups selected from It represents one or more groups selected from, Ar ₁ is And Ar ₂ is Except when. ) 2. An inorganic filler in an amount of 20 to 80% by weight based on the whole.
The electronic component sealant according to claim 1, further comprising: 3. A sealed electronic component which is sealed with the electronic component sealing agent according to claim 1 or 2.