What did these 5 packaging companies do to CSP LED?

Talked about for a long time of CSP, in the industry constantly controversial gradually grow up, today, online Jun no longer want to platitude, CSP how will the future, who will replace in the future, what is the general trend of what?. Because recently, when I was thinking about CSP, I found a very interesting thing, that is, "CSP" has changed and become chinese.

As everyone knows, CSP came out, then replace the original LED package remarks shocked four, which also became a major industry forum topic of debate, although still did not discuss what results, but there are still people some impressive speech.

Now, many people guessed right, but they didn't get the right answer. Know that CSP will have a part of the market, but also know from the beginning of the backlight, but we certainly did not expect the original CSP to the hands of Chinese enterprises, it happened so much change.

Packaging from CSP process

After such a long period of development, I think people are no longer in a strange position with CSP. At present, there are many ways to implement CSP white light process, among which the most ideal method is Wafer layer, but many enterprises are not the process at present. This is because the process of CSP, fluorescent glue can only cover the surface of its LED chip, blue light will leak through the sapphire from all sides, affecting the uniformity of color space distribution.

Because of this, so there are enterprises to consider removing sapphire, using thin-film chip technology, so that although the reduction of blue light leakage, but the process cost is too high, still can not become mainstream. This will lead to the mainstream technology roadmap is still cutting chip technology.

Because of the mainstream cutting technology, traditional packaging enterprises have the opportunity because they have similar fluorescent coating, testing, taping and other processes.

Now that packaging, then the current market CSP mainly has the following three major mainstream packaging structure:

A. is pressed by silica gel fluorescent powder. The five sides have light output and high light efficiency, but the consistency of color temperature at the top and the periphery is poor.

B. uses the protection of the surrounding titanium dioxide, and then the fluorescent film, only the top of a light-emitting surface, the light consistency and directivity is very good, but the loss of light output around the light effect will be low.

C. is made of full coverage of fluorescent film and fixed with transparent silica gel. It also has five sides with light emission, high light efficiency and poor light quality.

In addition to the packaging process itself, CSP has these packaging issues

First of all, over reliance on flip chip technology, such as chip cost, light efficiency, reliability, and chip resistance to ESD breakdown;

Secondly, the process of phosphor coating and its uniformity require high precision, which directly affects the color temperature, the rate of falling Bin and the color space distribution;

Third, CSP free packaging device, due to its small size, higher requirements on the accuracy of SMT patch;

Fourth, reflow soldering process will affect the void ratio of solder joints, thereby affecting the product's heat dissipation and reliability;

Fifth, LED chip and substrate thermal expansion coefficient difference, easy to stress, will directly affect the chip reliability;

Therefore, it is a key factor to ensure the reliability of the device in the development of CSP applications while ensuring the excellent optical efficiency and the reliability of the device.

Difficulties, packaging enterprises do what?

Although there are many problems in CSP, but as the leading enterprises in LED packaging, they are accelerating the development of products, they spent a lot of ideas on the CSP, the following is online, Wang asked some enterprises.

Ruifeng

In the past, single out CSP only considered the side light block, and did not guide and extract the light from the structure design. Ruifeng aims at improving the product structure of one side light emitting CSP and treating the white wall adhesive into a structure with an open inclined angle.

This structure can be the original in the white walls, phosphor particles, chip and colloid repeated reflection and refraction, is eventually absorbed into the horizontal direction of the heat excitation fluorescent glue part of photons through the white wall side guide wall inclined smooth, thus significantly enhance the light efficiency.

In addition to this, but also to mention the Ruifeng FEMC products, because the core of CSP or FC, and Ruifeng own EMC strengths and FC together, opened a new model of packaging enterprises. This development Elec-Tech as Dr. Mo Qingwei said, CSP is not a great scourges, it does not lock, instead it is a LED industry innovation, but also a challenge, but also new opportunities!

FEMC structure diagram

Lehman

The CSP device used by Lehman's process for preparation of fluorescent glue laminated is prepared, with no external device sealing structure, and by improving the configuration of the fluorescent glue, the thickness of phosphor layer and the top side of the regulation of CSP, can improve the consistency of optical devices, improve the CSP device in the spot terminal application problems the.

The preparation methods of CSP devices

Mega energy saving lighting

The traditional five aspect CSP (figure a) and single out CSP (as shown in Figure b) have been successfully produced and stabilized in 2017, and will continue to upgrade the established CSP structure transfer technology roadmap.

Compared to the SMD light source, five light CSP light source brightness and reliability has obvious advantages, but because of its unique structure, insufficient color uniformity shortcomings; in order to solve this problem, Siu Chi developed figure (g) shown in polyhedral light CSP; compared with the traditional five CSP, multi-faceted CSP light color uniformity significantly improved.

Traditional single