Thixotropic epoxy resin, preparation method and application in LED chip packaging

Abstract

The invention discloses thixotropic epoxy resin, a preparation method and application thereof in LED chip packaging. The preparation method consists of: (1) weighing bisphenol A epoxy resin, aliphatic epoxy resin, a thixotropic agent fumed silica, an adhesive force promoter, an antioxidant, an ultraviolet absorbent and a defoaming agent, and mixing them evenly to obtain a mixture 1; (2) weighing anhydride, diol, hydroxyl-terminated polybutadiene, and 2, 6-di-tert-butyl-4-methylphenol to carry out reaction to obtain a mixture 2; and (3) mixing the mixture 1 with the mixture 2, adding a phosphine-containing catalyst, and stirring the substances evenly at room temperature, thus obtaining the thixotropic epoxy resin. The method provided by the invention is simple, the technological parameters are easily controllable, and the preparation process does not involve solvent, and is green and environment-friendly. The obtained thixotropic epoxy resin has long storage life and good packaging effect. The thixotropic epoxy resin can be applied in chip packaging, and is especially suitable for chip packaging on a planar substrate, the glue mixing and dispensing process in original technology can be avoided, the production efficiency is high, the rate of finished products is high, and the cost is low.

Description

Technical field [0001] The invention relates to a thixotropic epoxy resin, a preparation method and its application in LED chip packaging. Background technique [0002] Semiconductor lighting technology is one of the most promising high-tech fields in the 21st century, and Light Emitting Diode (hereinafter referred to as LED) is its core technology. LED is a kind of light-emitting element that can directly convert electrical energy into light energy. Because it has low working voltage, low power consumption, high luminous efficiency, extremely short luminous response time, pure light color, strong structure, impact resistance and vibration resistance , Stable and reliable performance, light weight, small size and low cost, etc., which have been widely used and developed by leaps and bounds. [0003] The development of LED display devices has evolved from the dot matrix module in the late 1980s, to the later in-line tube and in-line series, and to the recent surface mount packaging...

AI Technical Summary

Problems solved by technology

Epoxy resin has high cross-linking density and high hardness as LED packaging material, but because of its brittleness, poor impact resistance, poor toughness, etc., there are many shortcomings, such as poor cold and heat shock resistance and high residual stress.

In addition, during long-term use, the ultraviolet light emitted by the chip or the outdoor use is irradiated by the sun's ultraviolet rays, which can easily lead to yellowing and aging of the packaging resin, reducing the luminous efficiency and life of the LED device.

[0005] The LED packaging step is a crucial step in the manufacturing process of LED chips, but there are many problems such as cumbersome process, complicated process, and not easy to control.

At present, epoxy potting glue is a liquid packaging material without thixotropic properties, so its packaging process route can only be applied to the manufacturing of single chip packaging, which has long production lines, high costs, low efficiency and batch Serious problem with poor stability

Moreover, the dispensing process packaging chip technology is only suitable for the packaging of chips with reflective cups, not for the packaging of chips and LED displays on planar substrates.

[0006] Moreover, the size of the chips used for color screens is getting smaller and smaller, and the pitch of the chips is also very small, which requires that the packaging resin must be able to quickly and large-scale package the chips on the planar substrate, and the current epoxy resin LED package Glue and encapsulation processes cannot be used for this purpose

[0007] In short, the epoxy resin glue packaging process of the existing LED chips can only be applied to the packaging of a single chip with a reflective cup and a chip on board (COB) with a dam, and it is easy to produce defective products and the process route is long. , long dispensing time, low yield, and low production efficiency, resulting in high production costs

The existing epoxy resin LED packaging glue is not suitable for the packaging of chips and LED displays on planar substrates

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