Introduction to the mechanism and characteristics of epoxy resin for LED packaging (detailed)

This article will introduce the mechanism, characteristics and application materials of epoxy resin encapsulated plastic powder. I hope that IC packaging engineers will help in selecting materials and elucidating the packaging mechanism.

The semiconductor ( LED ) packaging industry has occupied the main position of the IC property in the country. The question of how to choose the electronic packaging material needs to be answered more seriously. According to the data, more than 90% of the junction transistors and 70% to 80% of the integrated circuits have been applied to the plastic compound packaging materials, and the epoxy resin encapsulated plastic powder is the most common plastic compound packaging material. This article will introduce the identity, characteristics, and application materials of epoxy resin encapsulated plastic powder. I hope that IC packaging engineers will help in selecting materials and elucidating the packaging mechanism.

1. The purpose of LED packaging

The semiconductor package allows diodes, junction transistors, ICs, etc. to maintain their own airtightness, and to protect against the effects of humidity and temperature in the surrounding conditions, as well as to prevent the electronic components from being mechanically oscillated and impacted to cause damage to the components. Variety. Therefore, the purpose of the package is as follows:

(1) Preventing eczema and the like from invading from the outside;

(2) Supporting the wire in a mechanical form;

(3) usefully discharging the heat generated by the internal breeding;

(4) Supply a shape that can be accommodated or held.

The semiconductor component packaged in porcelain ceramics and metal materials has better airtightness and higher cost, and is used in combination with high requirements for high reliability. Semiconductor components packaged in a component compound plastic are inferior in airtightness, but are low in cost, and thus become mainstream in televisions, telephones, computers, radios, and the like.

2. Packaging the applied compound plastic material

Epoxy gum is used in most of the packaging of semiconductor products. Its general characteristics include: formability, heat resistance, outstanding mechanical strength and electrical insulation. At the same time, in order to prevent deterioration of the properties of the packaged product, the thermal expansion coefficient of the gum is small, the water vapor permeability is small, and the impurities which have an influence on the components are not contained, and the lead of the lead pin (LEAD) is excellent. It is very difficult for a pure gum to be able to purely meet the above-mentioned characteristics. Therefore, most of the gums are filled with a filler, a synergist, a hardener, etc. to be applied as a composite material. In general, epoxy gum has superior electrical properties, adhesion and outstanding low-pressure forming fluidity than other gums, and it is the most commonly used semiconductor molding material.

3. Composition of epoxy gum powder

In general, in addition to epoxy gum, the encapsulated rubber powder generally contains a hardener, a promoter, a flame retardant, a clever agent, a mold release agent, a filler, a pigment, a lubricating agent, etc., and is described as follows:

3.1 Epoxy gum (EPOXYRESIN)

The epoxy gums to be applied in the encapsulated plastic powder are bisphenol A (BISPHENOL-A), NOVOLACEPOXY, cyclic aliphatic epoxy gum (CYCLICALIPHATICEPOXY), epoxidized butadiene, and the like. The epoxy resin selected for packaging plastic powder must contain a low ion content to reduce the corrosion of the aluminum strip on the surface of the semiconductor chip, while having a high thermal deformation temperature, excellent heat and chemical resistance, and a hardener. Excellent reflection. Pure gum can be used, and it is also possible to confuse two or more gums.