JPS58176237A - Epoxy resin molding material - Google Patents

Abstract

PURPOSE:To provide the titled molding material having high reliability and suitable for use in the sealing of electronic parts, by adding an ion exchanger to a compsn. consisting mainly of an epoxy resin, a hardener and an inorg. filler. CONSTITUTION:0.01-20pts.wt. (per 100pts.wt. of the combined amount of components A and B mentioned below) one or more org. or inorg. ion exchangers such as a strongly acidic cation exchanger is added to a compsn. obtd. by blending a hardener (B) such as a phenol novolak, 150-450pts.wt. inorg. filler (C) such as silica and, if necessary, parting agent, flame retarder, flexibilizer, etc. with 100pts.wt. epoxy resin (A). EFFECT:Since ionic impurities such as Na ion and Cl ion contained in the moldings, which cause corrosion, are captured by the ion exchanger, there can be obtd. electronic parts, which have high reliability and do not corrode semiconductor elements sealed by resins.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an epoxy resin molding material, and particularly to an epoxy resin molding material suitable for encapsulating electronic components such as semiconductor elements.

BACKGROUND ART In recent years, thermosetting resin molding materials such as epoxy resins have been widely used for sealing electronic components such as transistor elements and integrated circuit elements. This is because the sealing operation is simpler and more economical than the conventional hermetic seal method using metal or ceramic materials. However, on the other hand, the resin sealing method has a drawback of being inferior in reliability against moisture compared to the hermetic sealing method.

That is, the reason why the resin sealing method has poor reliability against moisture is considered to be as follows. Molded products made of epoxy resin molding materials have hygroscopic properties, and moisture in the surrounding air permeates through the resin-sealed molded product and reaches the surface of the sealed electronic component. The problem is that ionic impurities such as sodium ions and chloride ions contained in the molded body are dissolved and transported to the surface of electronic components, causing corrosion of metal wiring such as aluminum. Most of these ionic impurities originate from epoxy resins, etc., which are raw materials for molding materials. It is common for epoxy resins for sealing to undergo purification treatment after synthesis. However, it is virtually impossible to completely remove ionic impurities. In addition, in epoxy resins, hydrolyzable chlorine, which is not an ionic impurity and can be ionized by the action of heat or catalyst, exists about 10 to 1000 times as much as chlorine, which is an ionic impurity, and this is also removed during manufacturing. It is difficult to do so.

As described above, epoxy resin sealing has problems with moisture resistance and corrosion resistance, and as a result of various studies, we found that if one or more ion exchangers are added to the epoxy resin molding material, metal wiring We have discovered a scale that significantly reduces or suppresses corrosion.

Based on the above findings, the present invention aims to provide an epoxy resin molding material suitable for manufacturing highly reliable resin-sealed electronic components.

That is, the present invention is characterized in that one or more ion exchangers are added to a composition whose main components are an epoxy resin, a curing agent, and an inorganic photonic agent.

The epoxy resin used in the present invention is not particularly limited in molecular structure, molecular weight, etc., as long as it has at least two or more epoxy groups in the molecule.

For example, any resin commonly used as a molding material may be used, such as a bisphenol epoxy resin, a phenol novolak epoxy resin, a cresol novolak epoxy resin, or an alicyclic epoxy resin. In this case, it is desirable to use a material that contains less ionic impurities such as sodium and chlorine, and less hydrolyzable chlorine.

Examples of the curing agent include phenolic curing agents such as phenol novolak resin and cresol novolac resin, amine curing agents, and acid anhydride curing agents. There is no particular restriction on the amount of these to be used, but it is necessary to consider the balance between the epoxy groups and the functional groups of the curing agent.

Next, as the inorganic photonic agent, for example, crystalline silica,
Examples include powders of fused silica, calcium silicate, alumina, calcium carbonate, talc, barium sulfate, and their fibers and glass fibers. These may be used in combination as necessary. Usually crystalline silica or fused silica is used. The blending ratio of this inorganic photonic agent varies depending on the resin content selected, but generally the resin content is 1
The amount may be about 150 to 450 parts by weight per 00 parts by weight. 1
If the appetizer is less than 0 parts by weight, the coefficient of thermal expansion and molding shrinkage will be large;
In addition, the thermal conductivity is low, and if the amount exceeds 450 parts by weight, there are disadvantages such as decreased fluidity and increased mold wear.

The types of ion exchangers to be blended in the present invention include:
There are organic ion exchangers and inorganic ion exchangers. Examples of organic ion exchangers include strongly acidic cation exchange resins having sulfonic acid groups, weakly acidic cation exchange resins having carboxylic acid groups, phosphonic acid groups, or phosphinic acid groups, and quaternary ammonium groups. There are strongly basic anion exchange resins having 1, weakly basic anion exchange resins having primary, secondary, tertiary amine groups, etc. Also included are heterocyclic compounds having a vinyl group, such as vinylpyridine and vinylmemidazole, alone or copolymers with divinylbenzene, and their quaternary ammonium compounds. Examples of inorganic ion exchangers include natural or synthetic zeolites, zirconium phosphate, zirconium oxide, and the like.

Furthermore, it is also possible to use one type or a mixed system of two or more of these ion exchangers. In addition, for cation exchangers, in addition to the hydrogen ion type, there are salt types such as ammonium salts, and for anion exchangers, in addition to the hydroxide ion type or free base type, borates and phosphates are available. Salt forms such as may also be used.

The amount of these ion exchangers added is 0 to 100 parts by weight of the total amount of resin and inorganic photonic agent.
．． The amount is preferably from 0.01 to 20 parts by weight, and if it is less than 0.01 part by weight, the moisture resistance and corrosion resistance will not be sufficient, and if it exceeds 20 parts by weight, the effect will not increase, so there is no need to add more than this amount. An inorganic ion exchanger as an ion exchanger can also function as an inorganic photonic agent. When used for such purposes, the added amount can be up to 450 parts by weight. If the amount added exceeds 45,050 parts by weight, the moisture resistance and corrosion resistance effects will not change, but fluidity during molding will decrease and mold wear will increase, which is not preferable. In addition,
These ion exchangers are preferably dried and made into as fine a powder as possible so that they can be easily dispersed uniformly in the composition.

The molding material according to the present invention may optionally contain a curing accelerator such as imidazole or tertiary amine, carnauba wax,
AM agents such as montan wax and stearic acid, flame retardants such as halogenated epoxy resins and antimony trioxide,
A coloring agent such as carbon black, a surface treatment agent such as a silane cassilling agent, an agent for imparting assembly flexibility such as a silicone compound, and the like may be appropriately added and blended.

The molding material according to the present invention can be easily produced by thoroughly mixing raw materials having a predetermined composition ratio using a mixer or the like, and then further melting and mixing the mixture using a heated roll, kneader, or the like.

As described above, the epoxy resin molding material according to the present invention provides high reliability when applied to, for example, encapsulation of semiconductor elements. In other words, resin-sealed semiconductor elements are subject to significant defects such as disconnection due to corrosion of aluminum wiring, even in moisture resistance tests under high temperature and high pressure steam.
Reduced or suppressed, maintaining the required performance over a long period of time,
It can be demonstrated. The reason for this is thought to be that ionic impurities that cause corrosion, such as sodium ions and chloride ions, contained in the molded body are captured by the ion exchanger, which is especially added, and cannot reach the aluminum distribution surface.

Next, the present invention will be explained in more detail with reference to Examples. In addition, in the following, parts indicate parts by weight.

Examples 1 to 8 170 parts of cresol novolac A boxy resin with an epoxy equivalent weight of 220, 60 parts of a brominated novolac epoxy resin with an epoxy equivalent weight of 280, 100 parts of a phenol novolak resin,
4 parts of 2-undecyl imidazole, 5 parts of carnauba wax
parts, 6 parts of silane coupling agent (γ-glycidoxyzolobyltrimethoxylane), 2 parts of carbon black,
A composition consisting of 8 parts of antimony trioxide and 700 parts of crystalline silica was mixed with the ion exchanger in the amount shown in the table, mixed with a mixer, kneaded with heated rolls, cooled, and then pulverized. A molding material was prepared.

Using each of the molding materials prepared in this way, a silicon element for evaluation having opposing aluminum wiring was sealed by transfer molding. And this sealing element has a temperature of 12
By applying a bias voltage of 20 V direct current between the electrodes under steam pressure at 5°C and performing a moisture resistance test B-POT (bias pressure wallaker test), we compared the time it takes for 50-chi elements to become open. The evaluation results are shown in the table.

As is clear from the table, it can be seen that the molding material of the present invention can provide excellent moisture resistance and corrosion resistance when a semiconductor element is encapsulated.

Comparative Example 1 - No ion exchanger added to the epoxy resin composition,
In addition, the ion exchanger was added in the amount shown in the table, and the other operations were the same as in the examples, and an evaluation test was conducted. The results are shown in the table.

Claims (1)

[Claims] An epoxy resin molding material characterized in that it is made by adding 11 g or two or more types of ion exchangers to a composition whose main components are an epoxy resin, a curing agent, and an inorganic photonic agent.