JP2000212238A - Phenol novolac resin and curing agent for semiconductor sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a phenol novolac resin improved in fluidity, moldability, water absorption resistance, and heat resistance by reacting a phenolic compound with a bridging base which forms xylene-skeleton-based bridging groups and o-hydroxyphenylmethylene group bridging groups. SOLUTION: A bridging base which forms 5-95 mol%, desirably, 10-90 mol% xylene skeleton bridging groups and ohydroxyphenylmethylene-base bridging groups is reacted with at least 1 mol, desirably, 2-10 mol, per mol of the bridging base, of a phenolic compound at 50-200 deg.C, desirably, 70-180 deg.C in the presence of 0.01-1 wt.%, based on the phenolic compound, synthesis catalyst to obtain a curing agent comprising a phenolic novolac resin of the formula. An epoxy resin composition obtained by mixing the curing agent with an epoxy resin in such amounts that the ratio of the hydroxyl groups of the curing agent and the epoxy groups of the epoxy resin is nearly unity is heated to 100-250 deg.C to obtain a cured epoxy resin product. In the formula, R1 to R5 are each H, a 1-4C alkyl or an aryl; and (m) and (n) are each an integer of 1 or greater.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenol novolak resin comprising a phenol compound as a skeleton component and a cross-link comprising a xylene skeleton group and an o-hydroxyphenylmethylene group. The resin can be used as a binder for organic and inorganic materials and as a curing agent for epoxy resins. In particular, phenol novolak resin is used as a curing agent for epoxy resins for the electrical and electronic industries, for sealing electronic components, and for laminate materials, and has excellent fluidity, low water absorption, and heat resistance. Useful as

[0002]

2. Description of the Related Art Epoxy resins are widely used as resin materials for electronic materials, and various phenol novolak resins, amines and acid anhydrides are used as curing agents for the epoxy resins. In particular, a phenolic novolak resin is mainly used as a curing agent for an epoxy resin for encapsulating a semiconductor (IC) in view of heat resistance and reliability. In recent years, the integration of ICs, the miniaturization and thinning of packages, and the application of surface mounting methods have been progressing, and the sealing materials for them have been further improved in thermal shock resistance and soldering heat resistance during surface mounting work. Is required. A major factor influencing the soldering heat resistance is the water absorption of the sealing resin material. In other words, the sealing material that has absorbed water generates internal pressure due to moisture vaporization at high temperatures during surface mounting work, causing internal peeling and package cracking, resulting in poor soldering heat resistance. Therefore, phenolic novolak resins used as epoxy resin curing agents are particularly required to have low water absorption.

As a method of reducing the water absorption of the sealing material, there is a method of increasing the amount of a non-water-absorbing filler such as silica in the sealing resin material. However, in this method, a new problem arises in terms of moldability due to an increase in the amount of silica, and it is desired that the resin itself has low water absorption.

[0004]

An object of the present invention is to solve the above-mentioned conventional problems and to provide a phenol novolak resin having a good balance of fluidity, moldability, low water absorption and heat resistance. It is what it was.

[0005]

That is, the present invention relates to a phenol novolak resin in which a resin skeleton component is composed of a phenol compound, and a crosslinking group in the resin is a xylene skeleton group and an o-hydroxyphenylmethylene group. This is the sealing curing agent used.

[Detailed Description of the Invention] Hereinafter, the present invention will be described in detail. The phenol compounds used in the present invention include phenol and phenols. As phenols, o-cresol, m
-Cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol. Further, xylenols, p-tert-butylphenol, p-tert-octylphenol,
o-allylphenol and the like. Preferably, phenol, o-cresol, o-ethylphenol, o
-Allylphenol, more preferably phenol.

Next, as a crosslinking base used in the present invention, a compound which forms a para-xylene skeleton crosslinking group and an o-hydroxyphenylmethylene group crosslinking group is used.

Examples of the compound forming a para-xylene skeleton cross-linking group include para-xylene dialkyl ether and para-xylene dichloride. The alkyl group of the para-xylene dialkyl ether is an aliphatic hydrocarbon having 1 to 10 carbon atoms and having a linear or side chain. Specifically, para-xylene dimethyl ether, para-xylene di-ethyl ether, para-xylene di-n-propyl ether,
Para-xylene di-iso-propyl ether and the like. Preferred are para-xylene dimethyl ether, para-xylene diethyl ether and para-xylene dichloride.

The compound forming an o-hydroxyphenylmethylene group crosslinking group is o-hydroxybenzaldehyde. Here, the o-hydroxyphenylmethylene group refers to a methylene group in which one hydrogen is substituted with an o-hydroxyphenyl group.

P-tolualdehyde, p-ethylbenzaldehyde, p-isopropenylbenzaldehyde, 3,
When a benzaldehyde having no hydroxyl group such as 4-dimethylbenzaldehyde is used, the curability and heat resistance are not sufficient.

The composition ratio of the xylene skeleton crosslinking group and the o-hydroxyphenylmethylene group crosslinking group in the phenol novolak resin obtained in the present invention is such that the xylene skeleton crosslinking group is 5 to 95 mol%, preferably 10 to 90 mol% of the whole crosslinking group.
Mol%, more preferably 20 to 80 mol%. If the xylene skeleton group is less than 5 mol%, the viscosity tends to increase, and the moldability deteriorates. In addition, when used as a curing agent, the water absorption increases, making it difficult to achieve the object of the present invention. If it exceeds 95 mol%, the heat resistance becomes poor.

In order to obtain the composition ratio of these crosslinking groups,
In the production of the phenol novolak resin, the proportions of the charged components may be substantially the same.

The mixing ratio of the phenol compound and the compound serving as a crosslinking group to be used in the present invention depends on the synthesis conditions, but it is usually required to be at least 1 mol of the compound serving as a crosslinking group. Preferably it is 2 to 10 moles. If the amount is less than 1 mol, the polymerization proceeds excessively, and the fluidity of the obtained phenol novolak resin may be lost, which is not preferable. Also, if too much, the recovery of raw materials will increase,
Not economic.

The phenolic novolak resin of the present invention comprises:
For example, they are synthesized as follows. That is, the phenol compound, the crosslinking base, and the synthesis catalyst are charged into a reactor at a predetermined mixing ratio, at a predetermined temperature, at a predetermined reaction rate, and after reacting to a predetermined reaction rate, an unreacted component is removed. obtain.

At this time, an acid is used as the synthesis catalyst, and organic acids such as oxalic acid, paratoluenesulfonic acid, and dimethyl sulfuric acid, and inorganic acids such as hydrochloric acid and sulfuric acid can be used. The amount of the catalyst used is 0.01% by weight based on the phenol compound.
It is selected and used in the range of １1% by weight. If the amount is too small, the reaction speed is slow. If the amount is too large, there is a problem that the reaction proceeds rapidly and the reaction cannot be controlled.

The reaction temperature depends on the mixing ratio of the reaction gas, but is usually 50 ° C to 200 ° C, preferably 70 ° C to 180 ° C.
° C, more preferably 80 ° C to 180 ° C. If it is too low, the polymerization will not proceed, and if it is too high, the control of the reaction will be difficult, and it will be difficult to obtain the desired phenol novolak resin.

The reaction time depends on the reaction temperature, but is usually within 10 hours.

The reaction is usually carried out under normal pressure, but may be carried out under a slight pressure or a reduced pressure.

After the reaction, unreacted phenol compounds and the like are removed under normal pressure or reduced pressure to obtain the desired phenol novolak resin. The general formula (1) of the phenol novolak resin obtained by the present invention has been described above.

(Equation 1)

Next, as a use of the phenol novolak resin as an epoxy resin, a curing agent will be described. Since this phenol novolak resin has a phenolic hydroxyl group, it can be used as a curing agent for an epoxy resin in the same manner as a normal phenol novolak resin. A cured product of an epoxy resin using the phenol novolak resin as a curing agent has low water absorption and heat resistance in a well-balanced manner.

The epoxy resin used in this case includes:
For example, bisphenol diglycidyl ether type epoxy resin in which an epoxy group is added to bisphenols such as bisphenol A and bisphenol F; Novolak type epoxy resin having an epoxy group; glycidylamine type epoxy resin such as diphenylmethanediaminetetraglycidyl ether and cyclohexanediaminetetraglycidylether; aliphatic epoxy resin such as epoxidized SBR and epoxidized soybean oil; 4,4′-dihydroxy Biphenyl and 3,3 ', 5
Dihydroxybiphenyl diglycidyl ether type epoxy resin having an epoxy group added to dihydroxybiphenyls such as 5′-tetramethyl-4,4′-dihydroxybiphenyl; polycyclic aromatic epoxy such as 1,6-dihydroxynaphthalenediglycidyl ether Novolak type epoxy resin, dihydroxybiphenyl diglycidyl ether type epoxy resin and polycyclic aromatic type epoxy resin are preferable, and novolak type epoxy resin is more preferable.

In order to obtain a cured epoxy resin using the phenol novolak resin of the present invention as a curing agent, for example, the hydroxyl group of the phenol novolak resin of the present invention can be obtained by the method described in JP-A-8-143648. So that the ratio with the epoxy group of the resin is approximately equal,
The phenol novolak resin of the present invention was mixed with the above-mentioned epoxy resin to form an epoxy resin composition,
Heat at about 250 ° C. At this time, it is preferable that a curing accelerator generally used for accelerating the curing, for example, N-methylimidazole, triethylamine, triphenylphosphine, or the like is added to the epoxy resin composition. If necessary, various additives such as a filler, a coupling agent, a flame retardant, a lubricant, a release agent, a plasticizer, a colorant, and a thickener may be added.

Next, the use of the phenol novolak resin of the present invention as a raw material for an epoxy resin will be described.
The phenol novolak resin of the present invention can be epoxidized into an epoxidized novolak resin. This epoxidized novolak resin is disclosed in, for example, JP-A-8-14364.
The phenol novolak resin of the present invention is obtained by reacting the phenol novolak resin of the present invention with an epihalohydrin such as epichlorohydrin in the presence of an alkali according to the method described in JP-A-8-108. The epoxidized novolak resin of the present invention can be cured using various epoxy resin curing agents. The obtained cured epoxy resin is excellent in low water absorption and heat resistance similarly to the above epoxy resin.

Examples of the curing agent for the epoxy resin in this case include various amines, polycarboxylic acids and their anhydrides, phenol novolak resins (including the phenol novolak resins of the present invention), urea resins, melamine resins and the like. Can be ordinary phenolic novolak resin,
Phenol novolak resins (including the phenol novolak resin of the present invention) such as orthocresol novolak resins and brominated phenol novolak resins are preferred.

In order to obtain a cured product of the epoxidized novolak resin of the present invention, an epoxy resin composition can be obtained in the same manner as in the above-mentioned curing method, and thereafter, the composition can be heated. The same applies to the point that a curing accelerator and other additives can be added. As described above, a resin obtained by using the phenol novolak resin of the present invention as a curing agent for an epoxy resin exhibits excellent properties in heat resistance, adhesion, water absorption, and mechanical properties.

Further, the epoxidized novolak resin obtained in the present invention is excellent even when a pigment such as carbon black, a filler such as asbestos, silica, talc, and a reinforcing material such as glass fiber, rock wool and cotton cloth are added. A resin having the above properties is obtained.

As described above, the resin obtained in the present invention can be used as a binder for organic and inorganic materials and as a curing agent for epoxy resins. It is suitable for use as an epoxy resin curing agent for the electrical and electronic industries, for sealing electronic components, and for laminate materials, and is mainly used as a sealant for semiconductors, especially for chip size packages. Suitable for semiconductor encapsulants.

[0028]

The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 A three-necked flask was charged with 2068 g (22 mol) of phenol, 122 g (1 mol) of o-hydroxybenzaldehyde, 1494 g (9 mol) of paraxylene dimethyl ether and 20 g of paratoluenesulfonic acid.
After reacting for an hour, unreacted components were removed by steaming. The obtained resin had a softening point of 68 ° C. and a free phenol component of 0.01 wt%. Table 1 shows the physical properties of the obtained resin. Next, the obtained resin 8
3.5 parts by weight, 100 parts by weight of epoxidized orthocresol resin (ECON-1020 manufactured by Nippon Kayaku Co., Ltd.) and 0.2 part by weight of triphenylphosphine were mixed, and mixed at 150 ° C.
After melting for 9 minutes, mold at 150 ° C (150 × 70 × 40m
m) was cast and cured to prepare a test piece. The curing conditions were as follows: curing at 150 ° C. for 8 hours;
Time went on. Table 3 shows the cured product properties of the obtained test pieces.

The methods for evaluating the properties of the obtained phenol novolak resin and the curing properties of the test piece are as follows. (1) Softening point According to JIS K2421 (ring and ball method), heating rate is 4 ° C.
/ Min. (2) ICI Viscosity Measurement The viscosity was measured at a plate temperature of 150 ° C. using an ICI cone plate viscometer (manufactured by Cordex Corporation). (3) Quantification of Free Phenol It was measured by gas chromatography. (4) Measurement of OH Equivalent A 2 to 3 g sample was acetylated with 1.25 g of acetic anhydride, and the acetic acid after acetylation was titrated with potassium hydroxide to determine the OH equivalent. (Acetylation method) (5) Water absorption According to JIS K6911, a test piece (50 ± 1 m in diameter)
m, thickness 3 ± 0.2 mm), immersed in hot water at 100 ° C. for 24 hours, and calculated from the weight increase before and after. (6) Measurement of Tg (glass transition temperature). It was measured by the TMA method. (7) Flexural strength and Young's modulus Measured according to JIS K6911.

Examples 2 to 7 and Comparative Examples 1 to 2 Phenol novolak resins were synthesized in the same manner as in Example 1 except that the reaction components and the amounts used were as shown in Table 1.
Test pieces were prepared according to the composition shown in Table 2 using the obtained resin. The physical properties of the obtained resin and the cured product properties of the test piece are shown in Tables 2 and 3, respectively.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

As described in detail above, the phenol novolak resin of the present invention provides a cured resin having a good balance of fluidity, moldability, low water absorption and heat resistance as a curing agent such as an epoxy resin. The obtained resin can be applied to a sealing material and can be used as a sealing agent, particularly as a sealing agent for semiconductors, due to the above characteristics.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J033 FA02 FA08 HB06 4J036 AA01 AC01 AD07 AD08 AE05 AF06 AF08 AF10 AH06 AH07 AK02 AK19 DB15 DC02 DC05 DC06 DC40 DD07 FB07 FB08 FB09 JA07 4M109 AA01 BA04 CA21 EB03 EB02 EB03 EB02 EB09 EB19 EC01 EC05 EC20

Claims (4)

[Claims] 1. A phenol novolak resin wherein the resin skeleton component comprises a phenol compound and the cross-linking group in the resin comprises a xylene skeleton group and an o-hydroxyphenylmethylene group. 2. The phenol novolak resin according to claim 1, wherein the composition ratio of the o-hydroxyphenylmethylene group in the crosslinking group is 5 to 95 mol% of the whole crosslinking group. 3. A hardening agent for sealing comprising the phenol novolak resin according to claim 1 or 2. 4. The sealing curing agent according to claim 3, wherein the sealing curing agent is a semiconductor sealing curing agent.