Category Archives: LED Packaging and Testing

By Debra Vogler, senior technical editor

February 23, 2011 — As gold becomes more expensive, copper wire bonding becomes more appealing for chip packaging. Reverse bonding, fine-pitch bonding, looping, second bonds, and other technologies are ramping on roadmaps, according to Kulicke & Soffa (K&S).

Bob Chylak, VP engineering, packaging & process integration at Kulicke & Soffa, was the featured speaker at a recent iMAPS NorCal chapter lunch meeting (Santa Clara, CA; 2/2/11). He covered the topic of converting from gold to copper for wire bonding — a move gaining ever greater interest by the surging price of gold. With heightened activities to close the knowledge gap with respect to using copper, many of the challenges have been addressed, observed Chylak.

Listen to Chylak’s interview:  Download (iPhone/iPod users) or Play Now

Laying out his company’s copper R&D roadmap (figure), Chylak noted that high-volume production of fine-pitch copper replacing gold already started in 2010. Advanced QFNs and stacked die still need to be developed, and LED packaging needs to be transitioned to copper, though Chylak noted that the challenge there will be with copper’s reflectivity not being as good as gold.

Click to Enlarge

Figure. Copper transition and roadmap planning. SOURCE: Kulicke & Soffa

Chylak said that nearly the entire K&S process engineering staff is working on the copper transition. In particular, work is being done on reverse bonding and getting yields to 50ppm or less. "It’s mainly around the looping [for stacked dies] and second bonds [including for LEDs] we’re focusing on," said Chylak.

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(September 3, 2010 – Marketwire) — Palomar Technologies introduced the fully automated 3800 Ultra Flexible Click to EnlargeDie Bonder, created for flexibility, high accuracy and precision.

The 3800 is based on Palomar’s three-generation Model 3500 Die Bonder. The 3.5 um repeatability 3 sigma and 2600 UPH over a 907.1 x 508mm work area enables its user to achieve high accuracy, precision and speed with flexibility in a wide variety of applications. Mutiple options include pulse heat and steady state stages for eutectic die attach applications.

Common applications include eutectic die attach, laser diode packaging and high-power LED packaging. Complex packages, often found in military, optoelectronic and medical devices industries, are well suited for the 3800. The 3800 is designed to eliminate additional bonders in the packaging facility.

Palomar Technologies provides high-precision wire bonders, gold wire bonders, die bonders and automated component placement systems. Find Palomar on the web at www.palomartechnologies.com. Visit Palomar’s blog at www.solutions.palomartechnologies.com.

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The Riley Report


May 19, 2009

Flip Chips and Flashlights
by George A. Riley, Contributing Editor

With the industry’s attention riveted on the next-generation of TSV&#151enhanced stacked&#151everything 3D marvels, we sometimes forget how microelectronics are changing everyday products in our world.

When a New England ice storm left my neighborhood without electricity for a cold week last December, flashlights went from household conveniences to survival necessities. I was pleased to find that research I was aware of several years ago for applying microelectronic assembly techniques to LED packaging has led to a new world of electronic flashlights with capabilities that your grandfather’s two D-Cell electric torch can’t match.

At the 2005 SMTA Emerging Products session which I chaired, Lumileds, the high-intensity LED pioneer, presented the conference’s award-winning paper on flip chip packaging of high-power LEDs. The thermal conductivity advantage of gold stud bump assembly over solder allows higher LED operating temperatures, and therefore higher light output.

Even the lower power of small LED pocket flashlights requires careful attention to heat removal. The usual cooling problem is not just how do we remove the heat, but where do we put it? In a ring array, LEDs are distributed around the periphery of the flashlight cylinder, moving the heat sources away from the center and apart from each other, while placing them at the heatsink&#151 the aluminum case.

One might expect a beam-forming problem in this scattered arrangement, but LEDs have several beam-forming advantages over the old-fashioned bulb. The plastic lens integral with each LED can be shaped to provide a radiation pattern ranging from Lambertian (center-weighted), to a broader beam, to side-illuminating.

Beyond that, the palm-sized personal flashlights we survived with turned the potential drawback of a six-LED ring into an advantage, producing a radiation pattern perfect for our needs, but not obtainable with ordinary bulb flashlights.

While a strongly focused spotlight beam is splendid for locating distant objects, it can be awkward for stumbling around in a pitch-black cellar. Think of the difficulty of using the ultimate focused beam, a laser pointer, to navigate that cluttered space. The ideal light for that purpose would combine a focused straight-ahead main beam with a wide-angle, dimmer but diffuse light for general awareness &#151as our LED flashlights did.

The light reflector positions a flat, patterned aluminum disk behind the ring of LEDs, with the highly-reflective vertical wall of the aluminum cylinder surrounding the ring. This simultaneously provides the best of both worlds: a beam about 6 feet in diameter, and a diffuse, uniform light emitted over about160 degrees horizontally and vertically.

Finally, the overall design meets our smaller-cheaper semiconductor obsession. The one-inch diameter aluminum case with a tail- cap push switch and a removable AAA battery pack is 3.5 inches long. The flashlight fits comfortably in the palm, and conveniently in a pocket, weighting about half as much as a D-size battery.

The filament-free LED adds robustness; LED efficiency promises longer battery life. Most surprising, a package with 6 of these flashlights and 18 batteries costs less than 20 dollars, even for panicked crowds of in-the-dark buyers. Three cheers for electronic flashlights, and the microelectronic packaging that makes them possible!

Contact George Riley

The SST Editorial Staff recaps SEMI’s recent Industry Strategy Symposium (ISS), and the Strategic Materials Conference (SMC) that followed, with this special report series available only on our website.

Analyst warns of “stealth inflation,” debt growth
One analyst presented a somber view of the world financial system and cautioned assembled executives about a shake-out he believes is inevitable. By Bob Haavind

A recession may be coming, but not to worry, ISS hears
The “R” word is spiking in the media, and even in blogs, speakers told concerned execs. But 2008 is far from 2001, they were reassured by Nariman Behravesh, chief economist and EVP for Global Insights, a forecasting firm with some 350 economists. By Bob Haavind

ISS panelists: Growth for 2008, “collision course” leads to stronger industry
Analysts in a midday panel discussion generally agreed that chip sales will stay in positive territory in 2008, after scraping out of 2007 with slim single-digit growth. One analyst cautioned we’re on a “collision course” that could make things temporarily rocky for equipment suppliers, but will help strengthen the chip industry long term. By James Montgomery

Wall Street wary of equipment stocks, but there are some bright spots
An insightful analysis of what chipmakers need to do to thrive in a period of “profitless prosperity” by Steve Newberry, president and CEO of Lam Research, set the stage for a spirited Wall Street panel. By Bob Haavind

Solid growth, clean financials, and alternate markets key to stock evaluations
What makes a process tool or material stock attractive to investors? Will private funds take over some equipment companies? How will the chip industry deal with exponentially rising design costs? By Bob Haavind

SMC highlights PV, LED, packaging materials
SMC showed amazing perspective on new electronic materials markets of gigantic scales like photovoltaics, high-efficiency lighting, and 3D and WLP packages. By Ed Korczynski

by Ed Korczynski, Senior Technical Editor, Solid State Technology

Last week hundreds of microelectronics industry executives gathered at ISS and SMC, absorbing the conventional forecasts for semiconductor manufacturing equipment and materials. But on the technology side, SMC showed truly amazing perspective on new electronic materials markets of gigantic scales like photovoltaics, high-efficiency lighting, and advanced 3D and WLP packages.

…Click here to read the full text…

These new orders consist of one new customer and a follow-on order from an existing customer, both based in the Asia-Pacific market. Amtech expects the $8.9 million in orders to ship in fiscal 2008, which began October 1, 2007. Since October 1, 2007, Amtech has received solar orders totaling approximately $27.8 million.

(December 17, 2007) TAIPEI, Taiwan — In line with the increasing use of LED backlight modules in display applications, Chunghwa Picture Tubes Ltd. (CPT) reportedly plans to step into upstream LED manufacturing, according to industry sources, reported CENS. CPT reportedly plans to have its affiliated Sintronic Technology Inc. take charge of LED packaging, and San Chih Semiconductor Co., Ltd. will be responsible for LED epitaxy.

Manufacturers of the MEMS (microelectromechanical systems) accelerometers at the heart of these radical interfaces, firms such as Analog Devices (Wii), STMicroelectronics (iPhone), and Freescale Semiconductor, are reaping the rewards as well.

(November 15, 2007) SAN JOSE, CA and SANTA CLARA, CA — Two companies have recently launched new LED packaging products. Philips Lumileds has launched its new cool-white LUXEON K2 with TFFC LED that is designed, binned and tested for standard operation at 1000 mA and can be driven at 1500 mA. In addition, LedEngin Inc. has announced its 10W, multiwavelength RGBA emitter, the LZ4-00MA10, which contains individually addressable dies in an 7mm square power LED package.

The Latest in LED Packaging


November 15, 2007

Philips Lumileds’ LUXEON K2 has thin film flip chip (TFFC) technology that contributes to overall light output improvement, excellent optical performance and improved thermal capability. New packaging advancements deliver a low thermal resistance 5.5° C/W. Light output performance from a LUXEON K2 with TFFC part binned and tested for 160 lumens minimum and 1A drive current can easily exceed 220 lumens at higher drive currents.

(November 16, 2007) SAN JOSE, CA — North American-based manufacturers of semiconductor equipment posted US$1.23B in orders in October 2007 (three-month average basis) and a book-to-bill ratio of 0.83, according to the October 2007 Book-to-Bill Report published by SEMI. A book-to-bill of 0.83 means that $83 worth of orders were received for every $100 of product billed for the month.

Single LED packages through complex power LED assemblies are evaluated at the lab, with customers encouraged to observe the in-house tests. A large one-meter integrating sphere determines color temperature (CCT) and brightness (TLF). A thermal imaging camera provides data for optimizing thermal management designs, used to extend the lifespan and light output of power LED assemblies. Other equipment includes a scanning electron microscope (SEM) with a Princeton gamma tech X-ray analyzer for failure analysis, and luminous flux and wavelength tester, a spectroradiometer system, and a goniometer. OPTEK provides comparison data for redesigns or LEDs designed to replace conventional lighting sources.

Phoenix Micro, a fables IC design house, provides next-generation, high-capacity intelligent ICs for mobile terminal devices. Intel Capital led series B funding in the company, which will use the investments toward developing storage ICs and facilitating end customers’ value-add and subscriber-management services.

(May 10, 2007) NEW YORK &#151 TT electronics OPTEK Technology opened an in-house visible LED laboratory with resources to assess LED packages on junction temperature variation, optical performance, and other parameters. The lab aids in design, manufacturing, and test.