LED circle 4 big coffee from the interpretation of the 7 aspects of CSP

About CSP market positioning

Q: the current CSP market positioning and technical differences at home and abroad?

Ashineon chief technology officer Liu Guoxu:

Due to the small size, CSP is closer to the source point, high current density and other characteristics, mainly popularized in the backlight and mobile phone flash applications in lighting applications CSP has just started, with the light effect, improve the performance and embodiment of flip chip mount equipment with the popularity of the trust in some lighting products will also show the advantage.

At present, several foreign LED manufacturers in the development and promotion of CSP great strength, walking in front of the domestic chip and packaging factory. However, this gap as before high power LED appeared so large, such as ashineon, Elec-Tech and other enterprises have been close to or surpass the technical level of international manufacturers, their products have achieved CSP volume shipments, with a certain degree of market competitiveness.

The relationship between CSP and on chip, package

Q: does the presence of CSP blur the boundaries between packaging and chip factories?

Tiandian photoelectric founder Xihong million:

Chip factory and packaging factory, manufacturers in foreign countries are complex, including South Korea, only the Greater China region of the chip and package are separated, which is the fundamental reason for us in a price war, whether it is the chip and package of discrete products are objective existence, only fit double "to produce one plus one is greater than two integration advantages.

Q: tell the truth, CSP in the end what will affect the packaging and chip factory?

Ashineon chief technology officer Liu Guoxu:

CSP versus chip factory is the layout of the flip chip in flip-chip, as well as the downward extension of the value chain. At present, the vast majority of CSP using flip chip structure; CSP in the application of the rapid development of the requirements of the chip factory to increase the size of Flip-chip, improve the efficiency and reliability of light. At the same time, some of the chips are also trying to Wafer-level on the phosphor coating in order to achieve the production process of CSP.

However, due to the cutting of the sapphire will leak white light from around, the first cut on the wafer and then cut the technical route has been limited. At present, the manufacture of CSP is still in the cut after the beginning of the square, with the traditional LED packaging process has more similarities, so many from the packaging line for process development and production testing. Allow all doubt, the appearance of the CSP line LED chip factory and packaging factory is more fuzzy, including the design of the bottom of the CSP solder joints during the application and failure mode will also be chip factory and packaging factory, work together to solve common optimization.

On CSP quality identification

Q: what are the key indicators to identify the quality of CSP?

Ashineon chief technology officer Liu Guoxu:

Screening CSP quality should focus on the following three aspects:

First look at the process level from the appearance structure: for the 5 surface light CSP, determine the cutting precision around the fluorescent glue thickness uniformity, combined with the distribution of fluorescent powder in the colloid uniformity on the surface, these two indicators can affect the uniformity of the appearance of the CSP color space distribution; in addition the viscous colloid surface very important, impact test, tape and patch.

Second, look at the performance parameters from the photoelectric test: this and other LED there is no difference, because the CSP size is smaller, the bottom point contact probe should pay special attention to the process not easy to produce residual glue or adhesive residue, impact test data. Other properties such as ESD resistance, thermal resistance, etc. are also worthy of attention;

Third, from the reliability test of trust: it can be said that this is the most noteworthy performance CSP. After being installed on the PCB board, the hot and cold impact can be used to screen out the solder joint problem caused by stress or the leakage problem of the flip chip under stress. Long term high temperature aging test can detect the anti-aging ability of fluorescent glue, inappropriate technology and materials will cause plastic cracking or peeling. It is worth mentioning that the silver plating layer and curing plastic material yellowing problem long plagued the framework of the LED no longer exists in CSP, therefore, there are many differences with the traditional failure mechanism of CSP package, in the evaluation of CSP quality in the focus will be different.

On the flip chip and CSP

Q: how to look at the relationship between flip chip and CSP development?

Innolux consultant Ye Guoguang:

Flip chip technology future will be the mainstream of LED, this trend should be obvious, the evolution of LED technology should be like the original IC package, which is no doubt, the question now is the flip price can not be more than the dress?

In the current state, or not, the cause of the problem in addition to the flip chip technology is more complex and high cost to pull a lower yield, although the performance of the device package does not make up or dress well, but the cost ratio increased, CSP may be a can reduce the cost of the line, because the CSP is simplified remove the package cost of the support, seems to have hope, but CSP has its problems, the first problem is that the yield of CSP, it is said that CSP yield is not high, especially with good rate of SMT chip CSP, the production equipment in production of CSP devices are also said to be more expensive, the high cost of depreciation. The two problem is that CSP can become one of the most important factors of the mainstream flip.

Whether it is CSP or flip, finally, the core issue is the chip, if the yield and cost of flip chip with no improvement, or flip CSP package process back to make up for the flip chip technology suits the competition cost, estimated there