LED flip chip knowledge 360 ​​degree analysis

What is an LED flip chip? In recent years, in the field of chips, flip chip technology is emerging, especially in the market for high-power, outdoor lighting applications. However, due to the late development, many people do not know what is called LED flip chip. What are the advantages of LED flip chip? Today, HC LED screen editor will give you a simple explanation. First of all, from the LED dressing chip to explain the LED flip chip, and the advantages and popularization of LED flip chip.

To understand the LED flip chip, first understand what is the LED dressing chip

LED positive-loading chips are the earliest chip structures and are commonly used in low-power chips. In this structure, the electrodes are on top, and the materials from top to bottom are: P-GaN, light-emitting layer, N-GaN, substrate. Therefore, it is a formal dress compared to flip-chip.

　

LED flip chip and symptom chip diagram

In order to avoid the LEDs occupying the light-emitting area in the chip, which affects the luminous efficiency, the chip developer designed the flip-chip structure, that is, inverting the chip, so that the light excited by the light-emitting layer is directly emitted from the other side of the electrode (the substrate is finally stripped). The chip material is transparent. At the same time, the structure of the LED package factory wire bond is designed for the flip chip. Therefore, the whole chip is called a flip chip, and the structure is widely used in high power chips.

Three major genres of formal, flip-chip, vertical LED chip structure

Flip-chip technology is not a new technology, but it existed long ago. Flip-chip technology is not only used in the LED industry, but also in other semiconductor industries. At present, LED chip packaging technology has formed several genres, and different technologies have different unique applications.

At present, there are three main types of LED chip structures, the most common ones are formal structures, vertical structures and flip-chip structures. The positive-fit structure is prone to current crowding due to the p and n electrodes on the same side of the LED, and the thermal resistance is high, while the vertical structure can solve these two problems well, and can achieve high current density and uniformity. In addition to the material cost, the reduction of the cost of the future lamps is particularly important in reducing the number of LEDs. The vertical structure can well meet such requirements. This also results in vertical structures typically used in high power LED applications, while formal technology is typically used in small and medium power LEDs. Flip-chip technology can also be subdivided into two categories, one is flip-chip based on sapphire chip, the sapphire substrate is reserved for heat dissipation, but the current density is not obvious; the other is flip-chip structure and stripped lining. The bottom material can greatly increase the current density.

LED flip chip advantages

First, there is no heat dissipation through sapphire, which can be used with large current; second, the size can be made smaller, the optical is easier to match; third, the heat dissipation function is improved, the life of the chip is improved; and the fourth is the improvement of antistatic capability; The fifth is to lay the foundation for the subsequent development of packaging technology.