Cooperating with Xintec to develop 8” wafer level Si-based package technology

In 2007, VisEra formally tapped into the LED market. Combining its profound technology know-how and extensive experience from the development of optical modules together with Xintec Inc’s new type of specialized LED silicon substrates, the two companies co-developed the 8” wafer level high power LED package technology and started mass production in 2009.

Xintec Inc is another one of TSMC’s strategic sub-investment in LED industry, it specializes in Wafer Level Chip Size Packaging (WLCSP) service including its development and foundry work; Xintec is also engaged in the development of front-end LED silicon substrate. The novel substrate for LED packaging is featured with good thermal conductivity, electric migration resistance by Cu metallization as well as higher light extraction efficiency.

Wafer level LED package technology features good thermal dissipation, consistent CTE and compact size

VisEra’s 8” wafer level silicon based package technology adopts patented miniaturization semiconductor MEMS process together with proprietary technologies such as TSV (Through-Silicon Via), lens modeling, conformal phosphor coating, where cutting is only conducted after full wafer has been packaged; with this procedure, it provides high productivity and lower the cost. The thermal resistance of the single chip LED package product is expected to be reduced to 2 Co/W and greatly lower the junction temperature (< 50 Co at Ta=25 Co).

J.C. Hsieh Ph.D further explained, compared to traditional plastic molding or ceramic packaging, VisEra’s silicon based LED package technology boosts thermal dissipation by 50%, extending the lifetime of components and enhancing durability and reliability. Moreover, the adoption of specially developed wafer level process is able to control CCT consistency for effective improvement in yield rate; while the miniaturization as well as multi-chip layout design, in response to market and customer needs, can further downsize the product and reduce costs.

Exclusive optical lens and phosphor coating technology to provide customers a total solution

Besides wafer level silicon package technology, VisEra’s process patents also include phosphor coating: its proprietary conformal coating technology is better than the conventional dispensing method for phosphor depsition, and will enhance LED light extraction efficiency. Additionally, VisEra offers optical lens specially designed for LED packaging, and complete lighting solutions for customized lens.

A new milestone of LED package technology to monthly output 3 million high power LEDs

Although wafer level Si-based LED packaging has established a new milestone of LED package technology, Mr. Lin indicated that this technology is reproducible. Currently, VisEra’s greatest advantage lies in its leadership in the market thus it is hard for makers falling behind to catch up. In terms of economic scale, having existing semiconductor equipment, VisEra and Xintec are able to save substantial costs at earlier stage and effiectively bring out the result with additional investment, reaching high cost-efficiency. As for technologies, VisEra has accumulated years of optical design ability and experience, capable of providing comprehensive solutions and creating more applications and business opportunities.

In terms of output, average monthly capacity of 1W LED exceeds 3,000,000 with acceptable yield rate. The production is expected to expand by 5 to 10 times next year depending on the demand of the end market.

According to a new market research study from Yole Developpement on HB-LED Packaging - 2009 Report, the market for WLP of HB-LED silicon modules is set to expand rapidly from about US$40M in 2008 to above US$200M by 2013. The availability of low cost 3D TSV "Through Silicon Via" Copper interconnect technology in the future will be key: indeed, silicon substrates will need WLP / TSV to reduce further silicon substrate area, cost and increase thermal dissipation in order to challenge competing HB-LED substrate technologies such as metal, ceramics and others.

Oriented at lighting market while taking wait-and-see attitude toward backlighting

On the outlook, Mr. Lin said that VisEra will focus on foundry services, especially the high power LED foundry services with 8” wafer level Si-based LED package technology. Optimistic about the upcoming high replacement rate in lighting market, VisEra will be dedicated to customers who require high performance, miniaturization and cost competitive solid state lighting, covering applications in streetlights, spotlights, recessed lights, indoor lighting and wide-angle lighting.

As for LED backlighting, VisEra continue to develop backlight LED package in hope of providing an exceptionally reliable solution at a best price performance ratio. As a new member in the LED industry, VisEra is unlikely to profit against the firmly established backlight players, and is risk-averse, Mr. Tseng remarked. He added that it is better to first focus on high power LEDs while waiting for the best chance to shift to backlight applications. Furthermore, in view of market demand, LED TV market will reach a plateau in 3 to 5 years, and its penetration rate will reach 70%; however, lighting market is only going to take off then, so the number of LEDs used in lighting is estimated to be higher than that in backlighting.

Insights from LEDinside

LEDinside observed that when the vertical integration between upstream and downstream makers has become a trend of the LED industru, some newcomers also start to provide professional specialized services with their own unique technologies and processes. Take VisEra for example, the company has tapped into LED market by offering foundry services based on its existing production lines and technical capability. On one hand, the technical breakthrough innovation is noteworthy; on the other hand, VisEra makes use of surplus production capability for LED packaging to save the vast capex required by wafer level packaging equipment, creating a high entry barrier for its followers.

The solid state lighting industry not only runs on large scale but also belongs to the new energy industry which receives substantial subsidies from governments around the globe. LEDinside predicts that there will be more M&A in LED industry in the future, and leading companies from various fields will take part in the competition. Stay tuned for further development.