Is it CSP spring season?

- May 16, 2018-

Is it CSP spring season?

Since 2013, CSP LED packaging has been a “no package” concept, which has caused a strong cold wind in the LED packaging industry.


The chip factory directly coated the fluorescent layer on the wafer, and directly obtained the LED lamp bead after cutting, eliminating the need for the solid crystal, bonding wire, and dispensing of the packaging plant. Indeed, many crisis-conscious packaging plants felt it. The relentless consequences of industry change.


If CSP really becomes the mainstream form of packaging, the more powerful the LED packaging factory, the harder it is to turn around. The huge investment in solid wire bonders has become a waste copper scrap, and the scale advantages of painstaking operation and management, like the Maginot Line, have collapsed instantly.

Second, the advantages of CSP


The CSP concept (chip scale package), derived from the IC package, refers to a package whose chip area is larger than 80% of the package area. The chip area exceeds 80% of the package area, resulting in minimal material waste; and the wafer level CSP package (wafer level package) can eliminate the bracket and simplify the material cost structure.


In addition to the enormous simplification of the packaging process, CSP has unique advantages in application.


First, a high-power, 1212-size CSP can achieve the same 1.5W power as the EMC3030. With this high-power advantage, CSP quickly spreads out in mobile flash applications. Second, the extremely small light emitting area of the CSP facilitates optical design. This has great advantages in applications requiring strict optical design, such as TV backlighting. Samsung, South Korea's most aggressive company for CSP applications, gave up the mature EMC 3030 direct-lit backlight about three years ago, sold the EMC stent line and turned to embrace the CSP.



Figure 1. CSP minimal light emitting surface (picture from network)


Third, the CSP dilemma


However, in the past three to four years, CSPs that once let packaging companies talk about color change have not replaced traditional bracket-type packages. Japan's veteran LED material company Nitto Denko, will produce CSP's fluorescent silica film technology, transferred to a Chinese company, it is a strategic retreat of the CSP LED package.


We can't help asking why CSPs that have subverted the packaging industry have stopped growing.


The CSP itself has a lot of structural problems. First of all, it is difficult to board. The volume of the CSP is too small, the pads are very delicate, and high-precision SMD machines are required. General end customers do not have such equipment and need new high-precision SMD equipment to invest.


Second, reliability risks. There is no dam structure around the CSP. The bonding force between silicone and chips and brackets is poor, and it is easily damaged by external forces and internal stresses, causing the risk of delamination or even shedding of the fluorescent layer.

Again, the cost is high. CSP adopts flip chip, and the price of flip chip was twice as much as that of the same size LED chip installed in 2013. Although the price has been declining, by mid-2017, the price is still higher than that of a regular-installed chip.


Although CSP theoretically greatly simplifies the package structure, it is limited by the cost of the flip chip and cannot be divided into 2835 and 3030 in general lighting. 2835,3030 as the mainstream of the general lighting market package, has a large scale cost advantage, but also CSP can not match.


Fourth, CSP breakout


Heavy mountain water re-doubt, the rise of LED car headlamp lighting, opened a silver lining of CSP packaging.


Philips creatively applies CSPs to headlights in automobiles to replace traditional halogen lamps. Auto parts companies in Guangzhou, Jiangsu, and Zhejiang are keenly aware of business opportunities and quickly follow up on imitations.


Figure 2. Philips LED car headlights (images from the network)


CSP's high-power, minimalist package is exactly what automotive headlamps require. The creation of a new application market opens the door for CSP. In addition to Lumileds, South Korean company Seoul Semiconductor also has a share in this emerging market. However, the cost, ease of use, and reliability of the CSP have not been resolved.


V. CSP promotion


The domestic packaging companies quickly followed up and tried to solve problems such as CSP, cost, ease of use, and reliability. At the just-concluded 2017 Guangya Exhibition, we saw some forward-looking LED packaging companies that have worked hard in various aspects to promote the application of CSP in automotive headlight lighting.


The Philips 2016 product developed by Hongli Zhihui has achieved the ultimate in cost. Hongli 2016 removed the Surge Protection Zener included with Philips 2016, simplifying the cost structure. According to end-customer news, one-third of the price of Philips can be achieved, which is almost the same as the ground cost of BOM. Hongli boldly applied the logic of the lighting market to automotive lighting as if it were Mulinsen. Hongli is likely to repel Lumileds and take the lead in the low-end automotive headlamp lighting market.


In terms of ease of use, the CSP-like substrate with a base plate facilitates placement. Guangzhou Tianxin introduced the 1860 dusting process class CSP. Three flip chips are fixed on the ceramic substrate, which greatly increases the area of the bottom land pad. SMD can be carried out very conveniently, considering the customer's use scenario.


In terms of reliability, the company's inorganic phosphor package 6018 uses a high-precision packaging process in the front-loading market. The inorganic phosphor package has the advantage that the phosphor layer does not fall off and is resistant to high temperature and high humidity. The Ostar series front package Ostar series uses this packaging process.


The inorganic phosphor package overcomes the disadvantage of the Philips 2016 silicone package. The disadvantages of the silicone chip falling off and falling in the high temperature and high humidity environment of the Tianxin 1860 dusting package are just a few headaches for the rear mounted lamp factory. The 6018 of LightCreation Company is said to be more price-competitive than Philips 2016, and it will use high-reliability cutting-edge technology to benefit the aftermarket.


Rayton new series CSP chips~A41

Sixth, summary

Waiting for four years, CSP has finally waited for flowers in the automotive lighting market. The new market will inevitably put forward new requirements for LED. The CSP still has a long way to go.